[Federal Register Volume 61, Number 208 (Friday, October 25, 1996)]
[Rules and Regulations]
[Pages 55412-55534]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 96-26838]
[[Page 55411]]
_______________________________________________________________________
Part III
Department of Labor
_______________________________________________________________________
Mine Safety and Health Administration
_______________________________________________________________________
30 CFR Parts 7, et al.
Approval, Exhaust Gas Monitoring, and Safety Requirements for the Use
of Diesel-Powered Equipment in Underground Coal Mines; Final Rule
Federal Register / Vol. 61, No. 208 / Friday, October 25, 1996 /
Rules and Regulations
[[Page 55412]]
DEPARTMENT OF LABOR
Mine Safety and Health Administration
30 CFR Parts 7, 31, 32, 36, 70, and 75
RIN 1219-AA27
Approval, Exhaust Gas Monitoring, and Safety Requirements for the
Use of Diesel-Powered Equipment in Underground Coal Mines
AGENCY: Mine Safety and Health Administration, Labor.
ACTION: Final rule.
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SUMMARY: This final rule establishes new requirements for the approval
of diesel engines and other components used in underground coal mines;
requirements for monitoring of gaseous diesel exhaust emissions by coal
mine operators; and safety standards for the use of diesel-powered
equipment in underground coal mines. The final rule is derived in part
from existing MSHA regulations, and provides protection against
explosion, fire, and other safety and health hazards related to the use
of diesel-powered equipment in underground coal mines. The final rule
also amends certain equipment safety standards in part 75 previously
applicable only to electric-powered equipment to apply to diesel-
powered equipment. The new standards are consistent with advances in
mining technology, address hazards not covered by existing standards,
and impose minimal additional paperwork requirements.
EFFECTIVE DATES: This regulation is effective April 25, 1997, except
for subparts E and F of part 7, the removal of part 31, the amendments
to part 36, and Sec. 75.1907 which are effective November 25, 1996.
Incorporations by reference were approved by the Director of the
Federal Register as of April 25, 1997.
FOR FURTHER INFORMATION CONTACT: Patricia W. Silvey, Director, Office
of Standards, Regulations, and Variances, Mine Safety and Health
Administration, 4015 Wilson Boulevard, Arlington, VA 22203-1984. Ms.
Silvey can be reached at [email protected] (Internet E-mail), 703-235-
1910 (voice), or 703-235-5551 (facsimile).
SUPPLEMENTARY INFORMATION:
I. Background
Coal mine operators began to introduce diesel-powered equipment
into underground mines in the early 1970's. The number of diesel units
operating in underground coal mines has increased from approximately
150 in 1974 to over 2,900 units operating in 173 mines in 1995. MSHA
projects that the number of diesel units operating in underground coal
mines could increase to approximately 4,000 in 250 underground coal
mines by the year 2000.
Although diesel-powered equipment does not have the inherent
electrocution hazard of electric-powered equipment, it nonetheless
presents a number of safety and health risks. By introducing an
internal combustion engine into an environment where explosive levels
of methane can be present, diesel-powered equipment brings with it
risks of fire or explosion. Diesel engines also have high temperature
exhaust components which, in the presence of coal and other
combustibles in the underground mine environment, present a fire
hazard. The handling and storage of diesel fuel underground also
present potentially serious fire hazards. Finally, diesel engines
produce exhaust gases containing carbon monoxide, oxides of nitrogen,
and particulate matter, presenting potentially serious health risks to
miners.
Before publication of this final rule, MSHA's regulations contained
limited safety and health and machine approval requirements that
specifically addressed the use of diesel-powered equipment in
underground coal mines. In the 1980's, the increase of the numbers of
this equipment in underground coal mines, coupled with the health and
safety risks associated with its use, highlighted the need for a
regulatory approach specifically tailored to diesel-powered equipment
operated in underground coal mines.
In response to this need, the Secretary of Labor convened a Federal
advisory committee in 1987 to evaluate and make recommendations for the
safe and healthful use of diesel-powered equipment in underground coal
mines. The Diesel Advisory Committee addressed approval issues--
covering equipment design and performance; use issues--addressing the
safe use of diesel equipment in the mine environment; and health
issues--concerning the evaluation and control of health hazards
associated with diesel equipment. In July 1988, the Committee issued a
report of its recommendations entitled ``Report of the Mine Safety and
Health Advisory Committee on Standards and Regulations for Diesel-
Powered Equipment in Underground Coal Mines''. In its report the
Committee concluded that MSHA should develop regulations to govern the
approval and use of diesel-powered equipment in underground coal mines,
and identified a number of specific areas to be addressed.
On October 4, 1989, the Mine Safety and Health Administration
published a Notice of Proposed Rulemaking in the Federal Register [54
FR 40950] that included criteria for the approval of diesel engines and
other related equipment; addressed exposure limits, monitoring, and
recordkeeping requirements for certain diesel emissions; and provided
corresponding safety standards for the use of diesel-powered equipment
in underground coal mines, including the safe storage and transport of
diesel fuel, and the training of persons performing work on diesel
equipment. On the same day, MSHA also published an Advance Notice of
Proposed Rulemaking [54 FR 40996] soliciting comment on the approach
and scope of an MSHA approval program for diesel machines. MSHA held
four public hearings on the proposed rule: in Salt Lake City, Utah;
Pittsburgh, Pennsylvania; Chicago, Illinois; and Birmingham, Alabama.
This final rule, which includes specifications for the approval of
diesel engines as well as provisions for the safe and healthful use of
such equipment in underground coal mines, is derived from the data,
information, and public comments compiled during the rulemaking
process. The final rule, like the proposal, takes an integrated
approach to the control of diesel safety and health hazards, requiring
clean-burning engines on diesel-powered machines, maintained by persons
who have been adequately trained for the task. Sufficient ventilating
air is required where diesel-powered equipment is operated to control
the potential health hazards of diesel exhaust. Sampling every shift
confirms the effectiveness of the mine ventilation system in addressing
these hazards.
Part 7 Equipment Approval
MSHA regulations require the Agency's approval of the design of
electrical equipment to be used in the production areas of underground
coal mines. This equipment must be designed to eliminate fire and
explosion hazards. MSHA's approval program has been very successful in
reducing the number of fires, explosions and other hazards associated
with electric-powered equipment. The final rule establishes a similar
approach for diesel-powered equipment used in areas of underground coal
mines where permissible (explosion-proof) electric equipment is
required, ensuring the same level of safety in mines where diesel-
powered equipment is used.
[[Page 55413]]
The permissibility requirements for diesel-powered equipment used
in gassy non-coal mines in MSHA's part 36 regulations have been in
place for a number of years. Although specific regulations did not
exist for diesel-powered equipment operated in underground coal mines,
MSHA has used the ventilation plan approval process to require the use
of permissible diesel-powered equipment, approved under part 36, in
those areas of underground coal mines where permissible electric
equipment is required. However, mine ventilation plans have generally
only addressed fire and explosion protection for equipment operating
near the point of coal extraction (inby), and other locations where
methane may be present, and have not addressed other possible safety
hazards associated with the use of diesel-powered equipment in other
(outby) areas. Additionally, mine ventilation plans have not dealt with
such important concerns as the storage and handling of diesel fuel and
regular maintenance of diesel equipment.
The final rule requires that only approved engines be used in
diesel-powered equipment in underground coal mines, and establishes
approval requirements for diesel engines to be used in both permissible
areas (inby) and nonpermissible areas (outby) under part 7, subpart E.
The subpart E approval requirements are modeled after existing approval
requirements in part 36 for engines used in gassy non-coal mines.
Certain other safety features, such as flame arresters, spark
arresters, and water scrubbers, must be added to the engines used in
permissible areas to ensure that they can be operated safely in the
coal mine environment. An engine in combination with these safety
features is termed a diesel power package. A separate approval was
established in the final rule for the power package because the power
package manufacturer is normally a company other than the engine
manufacturer and controls the assembly of the power package. In
addition, approval requirements for power packages under part 7,
subpart F, are incorporated into machines approved under existing part
36. This is similar to the approach taken for electrical equipment
where explosion-proof components are incorporated into machines
approved under part 18.
In order to protect miners from harmful contaminants emitted from
diesel engines, the approval requirements in the final rule contain
test procedures and limits on the concentrations of carbon monoxide and
oxides of nitrogen. Based on commenters' recommendations, the final
rule requires that the same test cycle be used for testing both the
gaseous and particulate emissions. In response to commenters'
recommendations, the final rule is based on ISO 8178, an international
consensus standard, which establishes a common test cycle for the
measurement of gaseous and particulate emissions. All equipment testing
under part 7 is intended to be conducted at test sites other than MSHA
facilities, such as manufacturers' laboratories, independent testing
laboratories, or other government or university laboratories.
Part 70 Exhaust Gas Monitoring.
The final rule addresses the monitoring and control of gaseous
diesel exhaust emissions. The final rule requires area sampling as part
of the onshift examination during every work shift. These monitoring
provisions will ensure, in a reliable and systematic manner, that
miners will be protected from exposure to harmful levels of gaseous
contaminants.
The final rule requires that mine operators take representative
samples of carbon monoxide and nitrogen dioxide in strategic locations
to determine concentrations of these contaminants in miners'
workplaces. The sampling locations are based on knowledge of the
specific operation of diesel equipment underground and the behavior of
gaseous emissions generated by these machines. Samples exceeding an
action level of 50 percent of the threshold limit values
(TLV) for carbon monoxide and nitrogen dioxide trigger
corrective action by the mine operator.
Part 75 Safety Requirements
The final rule specifies minimum ventilating air quantities in
areas where diesel equipment is operated, and requires that the
quantities be incorporated into the mine operator's approved mine
ventilation plan. As part of the equipment approval process in part 7
of the final rule, diesel engines used underground are tested for
gaseous and particulate emissions. The required minimum ventilating air
quantity is determined based on the results of these emission tests and
is included on the approval plate for each unit of diesel-powered
equipment. The approval plate quantity of ventilating air is the air
quantity needed to dilute the exhaust gases to their permissible
exposure limits. This air quantity should be used in ventilation system
design by the mine operator and in the evaluation and approval of
minimum air quantities in ventilation plans by MSHA.
Under the final rule individual units of diesel equipment must be
ventilated, as a general rule, with the air quantity specified on the
equipment's approval name plate. The quantity of air required in areas
where multiple units of equipment are operated is based on a simple
addition of approval plate air quantities. The final rule also allows
for adjustments in air quantities for multiple units of equipment, if
sampling of contaminants indicates that lesser air quantities will
result in dilution to the necessary levels. In addition, the final rule
establishes specific locations where air quantities must be measured.
Under the final rule, low sulfur fuel must be used to operate
diesel-powered equipment underground. Low sulfur fuel, which is readily
available and widely used throughout the United States, will lower
gaseous and particulate emissions, helping to protect miners from
exposure to harmful diesel exhaust contaminants. In addition, the final
rule prohibits the use of flammable liquids as additives in diesel fuel
used underground and requires that only additives registered with the
Environmental Protection Agency in accordance with 40 CFR Part 79 be
used in diesel-powered equipment.
The use of diesel fuel underground can present risks to miners'
safety, because the spilling of fuel on hot surfaces or electric
components, or the inadvertent ignition of stored diesel fuel, can
result in fire. Additionally, a fire started with a combustible
material other than diesel fuel that then spreads to diesel fuel stored
underground could be catastrophic. Diesel fuel handling and storage are
addressed in the final rule by specific requirements for diesel fuel
storage and the transportation of fuel from one location to another.
New design, installation, and maintenance requirements are
established under the final rule for fire suppression systems installed
on diesel-powered equipment and fuel transportation units. The
requirements in the final rule address the risk of fire on diesel-
powered equipment caused by, for example, hot exhaust components,
dragging brakes, and shorted electrical components igniting diesel
fuel, hydraulic fluid, brake fluid, lube oil, and other combustible
materials. The final rule also requires that automatic fire-suppression
systems be listed or approved by a nationally recognized independent
testing laboratory.
The final rule recognizes that regular maintenance of diesel-
powered equipment is essential. Inadequate equipment maintenance can
result in the creation of a fire or explosion
[[Page 55414]]
hazard, and the levels of harmful gaseous and particulate components in
diesel exhaust can rise when equipment is not adequately maintained. In
response, the final rule requires diesel-powered equipment to be
examined on the same weekly basis as electric equipment. The rule
specifically requires that air filters be changed and scrubbers be
flushed regularly, and that weekly gaseous emission tests be conducted
on certain diesel equipment while the engine is operating. The final
rule also requires that persons performing certain work on diesel-
powered equipment be qualified. Commenters agreed that requiring
diesel-powered equipment to be maintained in approved condition is
necessary to ensure that features installed to reduce the risk of fire,
explosion, and harmful emissions are operating properly. The final rule
does not adopt the proposal that MSHA approve the training plans used
for qualification. Under the final rule, training to establish
qualification for persons performing maintenance may be obtained
through the equipment manufacturer, community colleges, training
schools, or other training providers.
Amendments to Existing Part 75 Requirements
The final rule amends certain existing MSHA regulations in part 75
by extending their applicability to diesel-powered equipment. The final
rule requires that certain types of diesel-powered equipment be
equipped with methane monitors to detect dangerous levels of methane,
and also with cabs or canopies to protect miners from roof falls.
Additionally, the final rule clarifies that accumulation of coal dust
and other combustible materials is prohibited on diesel-powered
equipment. These safety features have been proven to save miners'
lives.
II. Discussion of the Final Rule
A. General Discussion
Recordkeeping Requirements in the Final Rule
Recordkeeping requirements in the final rule are found in
Secs. 7.83 and 7.97, Application requirements; Secs. 7.90 and 7.105,
Approval marking; Secs. 7.108, Power package checklist; Sec. 75.363,
Hazardous condition; posting, correcting and recording; Sec. 75.371
(r), (kk), (ll), (mm), (nn), (oo), and (pp), Mine ventilation plan,
contents; Sec. 75.1901(a), Diesel fuel requirements;
Sec. 75.1904(b)(4)(i), Underground diesel fuel tanks and safety cans;
Sec. 75.1911(i) and (j), Fire suppression systems for diesel-powered
equipment and fuel transportation units; Sec. 75.1912(h) and (i), Fire
suppression systems for permanent underground diesel fuel storage
facilities; Sec. 75.1914 (f)(1), (f)(2), (g)(5), (h)(1) and (h)(2),
Maintenance of diesel-powered equipment; Sec. 75.1915(a), (b)(5),
(c)(1), and (c)(2), Training and qualification of persons working on
diesel-powered equipment.
The paperwork burden imposed on manufacturers by the final rule
totals 558, which is an increase of 790 burden hours for the transfer
of hours from part 36 approval requirements, and a decrease of 232
hours for the removal of parts 31 and 32. In the first year the final
rule is in effect, the burden hours on mine operators will be 56,258,
of which large and small mine operators will incur 54,774 and 1,484
hours, respectively. After the first year, the burden hours to mine
operators will be 52,228, of which large and small mine operators will
incur 50,949 and 1,279 hours, respectively.
In the first year that the final rule is in effect, the total new
paperwork burden hours to mine operators and manufacturers will be
56,816 [56,258 + (790-232)]. After the first year, the total new
paperwork burden hours to mine operators and manufacturers will be
52,786 [52,228 + (790-232)].
MSHA solicited comments regarding the burden estimates or any other
aspect of the collection of information in the proposed rule. Proposed
paperwork requirements were submitted to the Office of Management and
Budget (OMB) for review in accordance with section 3504(h) of the
Paperwork Reduction Act of 1980 (PRA 80). Comments by OMB were filed
under comment numbers 1219-0111, 1219-0112, and 1219-0114. Control
number 1219-0100 was approved for proposed paperwork burden hours
required by part 7.
When proposed in 1989, the information collection requirements in
the diesel equipment regulations were calculated under PRA 80. The
final rule calculations are done in compliance with the Paperwork
Reduction Act of 1995 (PRA 95). Generally, changes in the final rule
burden hour and cost estimates from the proposed requirements result
from the revision necessitated by PRA 95. When the change represents a
regulatory change, it is so noted in the discussion of the appropriate
section within the preamble. For details on the calculation of
paperwork hours and costs see ``VII, Paperwork Reduction Act of 1995''
in the Regulatory Impact Analysis, which may be accessed electronically
or may be requested from MSHA's Office of Standards, Regulations, and
Variances.
Information is to be recorded, maintained for the period specified,
and made accessible, upon request, to authorized representatives of the
Secretary and to miners' representatives. Records are to be stored in a
manner that is secure and not susceptible to alteration, to preserve
the integrity of records for review by interested parties. This may be
done traditionally, by recording in a book, or electronically by
computer.
Examples of books that MSHA considers to be secure and not
susceptible to alteration include, but are not limited to, record books
that are currently approved by state mine safety agencies, and
permanently bound books. Examples of books that would not be considered
secure include loose-leaf binders and spiral notebooks.
Recognizing the trend of electronic storage and retrieval of
information through computers to be an increasingly common business
practice, MSHA permits the use of electronically stored records,
provided that they are secure and not susceptible to alteration, that
they are able to capture the information and signatures required, and
that information is accessible to authorized representatives of the
Secretary and miners' representatives. ``Secure'' is intended to mean
unalterable or unable to be modified. An example of acceptable storage
would be a ``write once, read many'' drive. Electronic records meeting
these criteria are practical and as reliable as traditional records.
Although the final rule does not require backing up the data, some
means is necessary to ensure that the condition and existence of
electronically stored information is not compromised or lost.
The 1995 Paperwork Reduction Act mandates agencies to encourage the
use of electronic submission of responses to minimize the burden of the
collection of information on respondents. Likewise, one of the major
objectives of Executive Order No. 12866 is to make the regulatory
process more accessible and open to the public as a means to reduce the
duplication of information between agencies. Elsewhere in this
preamble, MSHA announces the electronic availability of its rulemaking
documents with access instructions. The mining community and other
interested parties are encouraged to access on-line material as needed.
B. Section-by-Section Discussion
The following section-by-section portion of the preamble discusses
each provision affected. The text of the final
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rule is included at the end of the document.
General Discussion of Diesel Equipment Approvals and Safety
Requirements
One of the three major areas addressed by the Diesel Advisory
Committee was the approval of diesel-powered equipment. Historically,
MSHA and its predecessor agencies have approved equipment intended for
use in areas of mines where methane and other substances pose the
danger of a fire or explosion. Through the approval process, equipment
is evaluated against technical requirements which, when met, will
render the equipment safe for its intended use in the mine environment.
In part as a result of this process, the approved equipment used in
mines in the United States is recognized as among the safest in the
world.
The Advisory Committee recommended that diesel-powered equipment
for use in underground mines be subject to MSHA approval in much the
same way that electrical equipment has been regulated. Under existing
standards, electrical equipment operated in the area of extraction and
in return airways of underground coal mines and gassy metal and
nonmetal mines, where methane may accumulate, must be approved as
permissible (explosion-proof). Electrical equipment operated elsewhere
in these mines is not required to be permissible, but is subject to
certain safety requirements to protect against fire, shock, and other
hazards of operation. The Advisory Committee further recommended:
Only diesel-powered equipment currently considered
permissible should be permitted to continue to operate in areas of coal
mines where permissible electrical equipment is required.
Separate specifications should be developed for diesel-
powered equipment used in areas where permissible equipment is required
and elsewhere.
An approval program for diesel-powered equipment and
portable, attended equipment should be established. This program should
identify those equipment design features most readily addressed by the
equipment manufacturers.
A time schedule should be developed to allow for
conversion of outby equipment presently in use through retrofits,
replacement, or additional interim safety features to meet the
applicable new requirements.
Equipment newly introduced underground after a fixed date
should meet the new standards.
Current safety requirements including those that are
applicable to electric equipment should apply to diesel equipment as
appropriate.
Only approved diesel engines should be used in underground
equipment and the approval requirements should include measurements of
exhaust gas pollutants and determination of a nameplate airflow
quantity. Measurement of particulate generation should also be included
in the engine approval process.
In the proposed rule, MSHA outlined three new subparts for existing
part 7, which set approval requirements for diesel engines and power
packages to be used in underground coal mines. The Agency also gave
notice of its intention to develop approval requirements for fully
assembled diesel-powered machines under a proposed subpart H for
permissible equipment and subpart I for large outby equipment.
Requirements for a limited class of light-duty equipment and stationary
unattended equipment were proposed in part 75. A special class of
equipment consisting of ambulances and fire fighting equipment was
proposed that could be used in emergency situations as part of the
mine's evacuation plan. The proposal also included provisions to permit
fire prevention features in lieu of surface temperature controls for
diesel locomotives.
Currently, MSHA approves diesel equipment under 30 CFR Part 36 for
use in ``gassy noncoal mines''. In underground coal mines, ventilation
plans specify the use of diesel-powered equipment approved as
permissible under part 36 in areas where permissible electric equipment
is required. In addition to the equipment approval under part 36, MSHA
regulations address the approval of diesel mine locomotives in 30 CFR
Part 31, and of mobile diesel-powered equipment for noncoal mines in 30
CFR Part 32. The proposal suggested that parts 31, 32, and 36 could be
revised or revoked, and solicited comment. Some commenters favored
retaining all of the existing diesel approval regulations since they
still could have some application for equipment used in metal and
nonmetal mines. Commenters generally agreed that the proposed rules for
part 7 should supersede any applicability these existing approval
regulations have for diesel engines used in underground coal mines.
The final rule for part 7 governs the approval of diesel engines
intended for use in underground coal mines. As recommended by the
Advisory Committee and as set forth in the proposed rule, the final
rule requires that all diesel engines used in underground coal mines be
approved.
Part 7 was originally promulgated in 1988 to establish application
procedures and requirements for MSHA approval of certain products for
use in underground mines, with testing conducted by the applicant or a
third party. Traditionally, MSHA's role in approving products for
safety emphasized testing by the Agency. Under part 7, testing is
performed by the applicant or by a third party selected by the
applicant, with MSHA maintaining the right to observe product testing.
This approach has permitted MSHA to focus on its product audit function
and keep pace with technological improvements in mining products.
As originally promulgated, part 7 applied to only two types of
products: brattice cloth and ventilation tubing under subpart B, and
battery assemblies under subpart C. Subsequently, three additional
subparts were developed covering multiple-shot blasting units; electric
motor assemblies; and electric cables, signaling cables, and cable
splice kits. As designed, part 7 expedites the approval process, while
providing greater assurance that the products are manufactured in
accordance with safety specifications.
The final rule for part 7 is organized into two subparts--E and F.
Subpart E sets diesel engine performance and exhaust emission
requirements. As more fully discussed elsewhere in the preamble,
subpart E creates two classes of engine approvals--one for Category A
engines and one for Category B engines. Engines intended for use where
permissible electric equipment is required in underground coal mines
must have a Category A approval; engines for use elsewhere in
underground coal mines must meet the requirements for Category B
engines.
Subpart F of the final rule sets standards for safe design of
diesel engines with respect to both fire and explosion hazards. The
final rule establishes requirements for approval of diesel ``power
packages'' on engines intended to be used where electric equipment is
required to be permissible under existing standards. The term ``power
packages'' refers to an approved engine and those components added to
the engine, such as flame arresters, which prevent the ignition of
methane, and surface temperature controls, which prevent the ignition
of accumulations of combustible materials and combustible liquids.
Permissible equipment is designed to be explosion-proof.
Subpart G of the proposed rule would have established requirements
for diesel
[[Page 55416]]
power packages intended for use in areas of underground coal mines
where permissible electrical equipment is not required. As this
equipment is not designed to be operated in a potentially explosive
methane environment, the proposed rule would not have required these
power packages to have explosion-proof features. However, these diesel
engines do present fire hazards which must be controlled. Under the
proposal, subpart G would have set standards for surface temperatures,
exhaust cooling, and safety system controls. As discussed more fully
below, the final rule does not retain subpart G, but addresses these
hazards through new requirements in part 75.
The proposed rule, responding to a recommendation of the Advisory
Committee, also established a category of ``limited class of light-duty
diesel-powered equipment.'' This category included machines with light-
duty cycles, such as pickup trucks and personnel carriers. This
equipment, while light-duty as compared to production equipment, can,
nevertheless, present a fire hazard. For this ``limited class'' of
diesel-powered equipment, instead of requiring surface temperature
controls, the proposal set standards for fire prevention features that
would prevent fuel, hydraulic fluid, and lubricants from coming into
contact with hot engine surfaces. Features such as special fuel system
protection, fire suppression systems, safe electrical systems, and
engine compartment sensors that shut down the engine in the event of
overheating were specified in the proposal for additional fire
protection. Other necessary safety features, such as braking systems,
were also addressed by the proposal. As recommended by the Advisory
Committee, these requirements were not made part of the approval
process described above, but were set forth in the proposal as safety
standards for underground coal mines, appearing in 30 CFR Part 75.
The final rule retains many of the provisions of the ``limited
class'' concept in the proposal, but broadens the scope of the
equipment subject to these requirements to include all equipment not
required to be permissible (outby equipment). This change eliminates
the need for formal approval of outby equipment, and simplifies the
final rule. This aspect of the final rule, and the diesel-powered
equipment approval requirements, are discussed in detail under the
section-by-section analysis which follows.
In the proposed rule MSHA notified the public of its intentions to
develop two new approval regulations. Subpart H would have established
requirements for the approval of fully assembled permissible diesel-
powered equipment, and subpart I would have established approval
requirements for fully assembled nonpermissible diesel-powered
equipment. These sections would have included machine features
currently required by part 36 for permissible equipment and similar
features, described above, for ``limited class'' equipment. These
subparts would have required the incorporation of appropriate power
packages as described in proposed subparts F and G.
In the advance notice of proposed rulemaking, which accompanied the
proposed rule, MSHA requested comments on this regulatory approach.
Commenters objected to a formal approval program for nonpermissible
equipment, but supported the incorporation of machine safety features
in the use requirements specified in part 75. Commenters also supported
the need for continuing the approval program for permissible equipment.
In response to these comments, the final rule retains part 36 as
the basis for the approval program for permissible diesel-powered
equipment and adopts the machine safety features specified for the
limited class of light-duty equipment in the proposal for all
nonpermissible equipment. Subparts H and I are not further developed.
Instead, the final rule adopts the fire prevention features specified
for limited class equipment for all nonpermissible equipment.
Additionally, the final rule enhances the fire prevention features that
now apply to all nonpermissible equipment. This approach eliminates the
need for subpart G of the proposal dealing with power packages for
outby equipment.
The final rule makes certain revisions to part 36 to update and
make these existing requirements more flexible. The final rule revises
part 36 to remove references to ``gassy noncoal mines and tunnels'',
thus making these existing regulations applicable to equipment intended
for use in coal as well as in metal and nonmetal mines. In addition,
part 36 is amended to afford equipment manufacturers the option of
incorporating in equipment submitted for approval either a part 7,
subpart F power package, or engine and safety component systems that
meet the existing requirements of part 36. Under the final rule, part
36-approved equipment with a part 7, subpart F power package will be
suitable for use in underground coal mines where permissible electrical
equipment is required. Part 36 equipment with engine and safety
component systems certified under part 36 will continue to be
recognized for use in metal and nonmetal mines where permissible
equipment is required.
These changes are responsive to commenters who recommended that
part 36 continue to be utilized for approving diesel-powered equipment.
The final rule revisions to part 36 also retain, as recommended by
commenters, a distinction between approval requirements for equipment
used in coal mines and approval requirements for metal and nonmetal
mining equipment.
The final rule revokes parts 31 and 32. MSHA previously identified
these regulations for elimination in its response to the President's
March 4, 1995, Regulatory Reform Initiative. Parts 31 and 32 are
outdated and, with the final rule changes to parts 7 and 36, are
obsolete. Only nine approvals have been issued under part 31 since its
inception, and none have been issued since 1977. No other MSHA
standards require part 31-approved equipment, and diesel mine
locomotive manufacturers have submitted approval applications under
part 36 for locomotives intended to be used where permissible equipment
is required. With the revocation of part 31, diesel mine locomotive
manufacturers may continue to acquire equipment approvals under part
36.
The part 32 approval requirements for mobile diesel-powered
equipment used in noncoal mines are likewise unnecessary. No MSHA
regulation requires the use of part 32 equipment, and no part 32
machine approval has been issued since 1981. Part 32 engine
certifications have continued to be issued by MSHA, however, and some
state and federal agencies' regulations make reference to part 32.
State and federal agencies that reference part 32 are directed to look
to part 7, subpart E, which contains engine requirements, and to
Secs. 75.1909 and 75.1910, which contain the requirements for other
machine features. Together, these final standards cover the
requirements previously found under part 32. These new sections of the
final rule will continue to accommodate those government agencies that
reference MSHA approval or certification regulations.
Likewise, manufacturers seeking part 32 engine approvals will be
able to acquire the requisite engine approval through the new part 7,
subpart E. Existing part 32 engine approvals continue to be valid.
A significant issue for the Advisory Committee and in the proposal
was the schedule set for compliance with the new standards for diesel-
powered equipment. The Advisory Committee
[[Page 55417]]
recommended that MSHA require diesel equipment newly introduced
underground to meet the new standards after a certain date. The
Committee further recommended that MSHA set a schedule for existing
diesel equipment to meet any new requirements.
The proposal called for the part 7 approval requirements to be
effective 60 days after publication of the final rule. The schedule for
requiring in-mine use of diesel equipment meeting the new requirements
was set by proposed Sec. 75.1907. Under these provisions, the new
requirements would have been met over a schedule ranging from six
months to five years after the effective date of the final rule.
The final rule follows the approach of the proposal, setting
effective dates for the new approval requirements, as well as the
schedule for requiring in-mine use of diesel-powered equipment which
meets the new requirements. In response to the comments and as a result
of not adopting proposed subparts G, H, and I, the final rule sets a
compliance schedule ranging from 60 days to three years after
publication of the final rule. In order to facilitate implementation of
the final rule, MSHA will begin accepting approval applications under
revised parts 7 and 36 immediately. In addition, MSHA will continue
power package testing until the Agency determines that a competitive
capacity exists in the private sector. At that time, MSHA will
discontinue power package testing and rely solely on the part 7 testing
provisions.
Subpart E Overview
Subpart E of the final rule is new and amends existing part 7. As
an amendment to these existing regulations, the general administrative
provisions of subpart A of part 7 apply to the new subpart E
application requirements.
Subpart E establishes engine performance and exhaust emission
requirements for MSHA approval of diesel engines for use in underground
coal mines. As discussed elsewhere in this preamble, diesel engines for
use in metal and nonmetal mines are approved under part 36.
The final rule, like the proposal, creates two classes of engine
approvals--Category A and B--for diesel engines to be used in
underground coal mines. Several commenters objected to the proposed
approval of diesel engines for use in outby areas, noting that outby
electrical equipment is not subject to approval under existing
standards. However, other commenters stated, and the Diesel Advisory
Committee acknowledged, that all diesel engines in underground coal
mines should meet certain safety and performance specifications. In its
report the Advisory Committee suggested that, depending on equipment
location and use, different requirements would be appropriate for
diesel engines. One commenter to the proposal recommended that all
diesel engines be approved as permissible.
For underground coal mines, MSHA believes that clean-burning
engines are critically important. Unlike electrical equipment, diesel
engines emit exhaust which contains toxic gases that can be harmful to
miners. Inappropriately designed engines can pollute the mine
atmosphere excessively, elevating toxic gases to levels that cannot be
controlled with normal ventilation practices.
To achieve the objective of clean-burning, appropriately designed
engines in mines, the final rule sets performance standards for all
diesel engines, whether they are operated in the face area or outby.
The emission test requirements for Category A and B engines are the
same, except that Category A engines are tested with methane injected
into the intake system. Equipment operating at or near the point of
coal extraction and in return air courses may encounter concentrations
of methane gas, which is liberated during mining. Testing an engine
with methane injected in its intake simulates operation of the engine
in these areas of coal mines. Operation in methane atmospheres causes
an increase in exhaust emissions, which requires higher ventilation
rates.
Under the final rule, diesel equipment used in areas where
permissible electrical equipment is required by existing standards
incorporate fire and explosion prevention features provided by a power
package. Such a power package must include a Category A engine and
components added to the engine to prevent the ignition of methane and
accumulations of combustibles. Power packages intended for use with
Category A diesel engines must be approved under part 7, subpart F of
the final rule.
Current safety standards require that intake air courses in areas
away from or outby the mining face be maintained free of explosive
concentrations of methane. Engines used on equipment operated in these
outby areas must have a Category B approval under the final rule.
Engines approved under Category B are emission tested without the
injection of methane into the engine's intake system.
The proposed technical requirements for diesel engines addressed
the control of gaseous exhaust emissions and quantification of the
engines' particulate matter generation. The proposed rule also set
specifications for the equipment used and the standard laboratory test
conditions for determining gaseous and particulate output for diesel
engines. The proposed requirements for measuring gaseous emissions were
derived from now-removed part 32 and existing part 36, and the proposed
requirements for measuring diesel particulate were based on the
Environmental Protection Agency's requirements published in 40 CFR Part
86. In addition, the proposal specified the engine operating parameters
as well as a method to calculate the ventilation rate and particulate
index for the engine.
Engine manufacturers do not manufacture engines specifically for
mining. Typically, ``off-road'', heavy-duty diesel engines are utilized
in mining equipment. Over-the-road utility vehicles and smaller general
industry equipment are also used in mines. At the time of the proposed
rule, the only certification test specifications designed for engines
used in mining were the MSHA engine certification standards in now-
removed part 32 and in existing part 36.
In the proposal, MSHA used its rules in now-removed part 32 and
existing part 36 for the steady-state test for gaseous diesel exhaust
emission. The test equipment specified in the proposal for diesel
exhaust particulate measurement was modeled after the transient test
equipment required in 40 CFR Part 86, subpart N.
Commenters to the proposal stated that a correlation should not be
made between MSHA's proposed rule and then-current EPA testing, because
the proposal used a test with specific points in a ``steady state'',
while EPA used a ``transient test.'' Commenters also recommended using
the same test cycle for both gaseous and particulate matter. In
addition, commenters generally recommended comparability of testing for
similar types of tests and indicated a desire to use international
standards whenever possible.
The International Organization for Standardization (ISO) has
prepared ``ISO 8178 Reciprocating Internal Combustion Engines--Exhaust
Emission Measurement'', which includes test specifications for off-road
diesel engines. The ISO is a recognized international standard-setting
body. Equipment manufacturers, as well as other standard-setting
bodies, make reference to and adopt the standards developed by the ISO.
[[Page 55418]]
ISO 8178 is an international test standard for measuring off-road
diesel engine emissions. It contains a detailed description of the test
equipment requirements and standard procedures for conducting a steady-
state test to determine both gaseous and particulate emissions. The ISO
8178 procedures also specify an 8-point test cycle for measuring both
gaseous and particulate emissions. ISO 8178 does not set emission
limits.
The final rule is based on the ISO 8178 ``Reciprocating Combustion
Engines--Exhaust Emission Measurement'', part 1 test procedures that
apply to gaseous and particulate emission testing for diesel engines.
This change from the proposal is responsive to commenters' concerns
about correlating the proposed rule and EPA diesel engine tests, and
simplifies the test procedures. For example, under the final rule the
gaseous emission tests are reduced to 8 test points from 39 test points
under the proposal. The particulate emission tests are also reduced
from 10 to 8 test points. In addition, the final rule permits the tests
for exhaust gaseous and particulate emission tests to be performed
concurrently following the same test cycle, rather than independently
following different cycles. A number of minor changes are made in
Secs. 7.86, 7.87, 7.88, and 7.89 of the final rule, so that the tests
performed under these sections conform to the ISO 8178 requirements.
Substantive changes to these sections are discussed in this overview
and in the section-by-section discussion that follows.
The final rule adds one requirement to the ISO 8178 test
procedures. Section 7.89(a)(5)(iii) requires that 1.0 percent of
methane be added to the intake air for testing Category A engines. This
addition to the ISO 8178 procedure should present no technical
difficulties for manufacturers or third-party laboratories. MSHA,
however, will provide technical assistance for setting up this aspect
of the test procedure upon request. The final rule also requires a test
to determine the maximum fuel-to-air ratio, and specifies requirements
for determining the gaseous ventilation rate and particulate index for
diesel engines.
Basing the final rule on an international consensus standard
enables diesel engine manufacturers to test with a single set of
procedures common to both the United States and foreign markets. Also,
existing test facilities established to perform tests to these
international standards can be used to perform the tests prescribed by
this final rule. In addition, use of the ISO 8178 test procedures leads
to better comparability with international testing practices, and
provides a more competitive posture for American products in foreign
markets. Many off-road engine manufacturers are already complying with
EPA and California Air Resources Board (CARB) requirements, which
include testing in accordance with ISO 8178 procedures.
One commenter to the proposal objected to permitting engine
manufacturers or third-party laboratories to test diesel engines for
conformance to approval standards, questioning the objectivity of such
an approach. MSHA experience over eight years with manufacturers and
third- party laboratory testing under existing part 7 and the Agency's
program for off-site testing (POST) of diesel engines confirms that
non-MSHA testing is performed competently and produces reliable
results. In addition, MSHA will initially witness all tests conducted
by manufacturers and third parties to ensure continued reliability of
test results. In all cases, MSHA will accept only results of tests
performed by manufacturers or third-party laboratories which have the
capability to competently perform the required tests with properly
calibrated instrumentation.
Section 7.81 Purpose and effective date. The part 7, subpart E
approval requirements are effective November 25, 1996. MSHA will begin
accepting applications under subpart E immediately, but will complete
any in-house part 32 applications, or evaluate such applications under
the new part 7, subpart E, at the applicant's choice. As discussed
elsewhere in this preamble, the requirements for the use of approved
diesel engines in underground coal mines are effective in 3 years.
Commenters to the proposal generally supported the approval
requirements of subpart E for diesel-powered equipment to be used in
underground coal mines. Several commenters suggested, however, that a
phase-in period, up to three years, be established. According to these
commenters, manufacturers would use the phase-in period to gain
experience with the new test procedures, become familiar with new
engine approval application procedures, and re-evaluate their existing
approvals.
The final rule does not incorporate a phase-in period for diesel
engine approvals. Diesel engine manufacturers and third-party testing
facilities are familiar with the ISO 8178 test procedures on which the
final rule is based, and have the capability to perform these tests in
their laboratories with minor changes. In fact, two engine
manufacturers and a testing laboratory have tested diesel engines for
MSHA approval using the ISO 8178 procedure.
With this diesel engine testing experience and capability already
present in the marketplace, MSHA finds no reason to provide an extended
phase-in period for the approval standards for diesel-powered
equipment, and anticipates that manufacturers and third-party testing
laboratories can immediately begin testing engines under subpart E.
Section 7.82 Definitions. In addition to the existing definitions
in Sec. 7.2, Sec. 7.82 of the final rule sets out and clarifies the key
terms which apply in subpart E. Commenters generally agreed with the
proposed definitions, which were derived from definitions developed for
ISO 8178 and the Society of Automotive Engineers (SAE) Recommended
Practice J177.
No comments were received on the proposed definitions for
``Category A engines'', ``Category B engines'', ``corrosion-resistant
material'', ``diesel engine'', ``exhaust emission'', ``percent load'',
and ``steady-state condition''. These terms and their proposed
definitions are adopted in the final rule.
The definitions of the terms ``rated speed'' and ``intermediate
speed'' in the proposed rule have been modified in the final rule in
response to a commenter who recommended that MSHA's definitions of
these terms conform to definitions contained in internationally
accepted standards. The definitions of these terms in the final rule
are conformed to the definitions in ISO 8178.
The term ``peak torque speed'' in the proposed rule has been
changed to ``maximum torque speed'' in the final rule to conform with
ISO 8178. Both terms convey the same meaning.
One commenter objected to the definition of ``diesel particulate
matter'' as ``any material, with the exception of water, which is
collected on a filter passed by an air diluted exhaust stream.''
According to this commenter the proposed definition was vague and too
dependent on the filter used and method of sampling. The final rule
does not include the proposed definition, adopting instead the
definition for diesel particulates contained in ISO 8178. The ISO
definition is more specific, providing that diesel particulates are
``any material collected on a specified filter media after diluting
diesel exhaust gases with clean filtered air at a temperature less than
or equal to 325 K (52 deg. C) as measured at a point immediately
upstream of the primary filter. This is primarily carbon, condensed
hydrocarbons, and sulphates
[[Page 55419]]
and associated water.'' In addition, the filter and sampling methods,
which are well detailed in ISO 8178, are included in the final rule.
The objective of this definition is to facilitate accurate, repeatable
tests for the diesel particulate matter in an engine's exhaust. Other
definitions may be more appropriate for addressing health effects.
The same commenter also objected to the proposed definition of
``total oxides of nitrogen'' as focusing only on nitric oxide and
nitrogen dioxide. The commenter suggested revisions to these
definitions and offered definitions for several other terms used in the
proposed rule, including ``gaseous ventilation'', ``particulate
index'', ``threshold limit value'', ``permissible exposure limit'' and
``recommended exposure limit.'' According to the commenter, these terms
were not used consistently in the proposal. The final rule does not
adopt these suggested changes. Many of these terms have accepted
meanings that are well known. However, changes throughout the final
rule have been made to be sure the terms are used consistently and
appropriately.
The proposed definition of rated horsepower is revised in the final
rule to conform with current procedures for evaluating engines under
existing part 36. This change will help define an engine's power output
as it is related to performance testing. A definition for the term
``operational range'' is added to also conform with current procedures
for evaluating engines under existing part 36.
Section 7.83 Application requirements. The proposed application
requirements were derived from now-removed part 32 and existing part 36
and are largely unchanged in the final rule. The application procedures
are designed to provide sufficient information to demonstrate
compliance with the technical requirements of subpart E, and form the
basis for approval of diesel engines.
The final rule adopts the proposal to permit applicants to submit
composite drawings in lieu of individual drawings. This approach
reduces paperwork and affords applicants flexibility in the preparation
of their drawings.
The final rule also provides for certain information to be
submitted after approval testing. This information includes the
ventilation rate and particulate index for the engine, and the fuel
deration chart, which provides guidance for how to adjust approved
engines to compensate for altitude.
Like existing part 7 and other MSHA approval standards, the
documentation formulated in the application process forms the basis for
MSHA's approval. Approved diesel engines must be manufactured in
accordance with the specifications contained in the approval and, once
put into service, approved engines must be maintained and operated
within the parameters set in the MSHA approval.
In general, commenters concurred with the proposed application
requirements. One commenter suggested that a description of the design
features which promote efficiency and control over production of toxic
emissions specifically include fuel injection timing. MSHA agrees that
specifications for the fuel injection system of diesel engines and the
fuel injection timing are key in controlling exhaust emissions. The
proposal included a requirement that the fuel injection system be
detailed in approval applications. However, a requirement specifying
the fuel injection timing was not included in the proposed rule.
The final rule adopts the proposed requirement for a description of
the fuel injection system, and adopts in paragraph (b)(6) the
suggestion that fuel injection timing also be specified. This
information had been required in now-removed part 32 and is required
for part 36 engine approvals and to help ensure accurate measurement of
the engine's emissions during the tests and proper maintenance of the
engine's fuel injection timing.
Although the Agency allows electronic record storage in other areas
of this regulation, electronic computer submission of part 7 approval
applications is not yet available. MSHA's Approval and Certification
Center is developing a means for computer submission, and at present
has pilot programs to facilitate the use of electronic reporting.
However, the system is in the formative stage and is not yet available
for public use.
The paperwork hours in the approval application, including test
requirements, are assigned OMB control number 1219-0100.
Section 7.84 Technical requirements. This section of the final rule
sets the specific technical requirements for Category A and Category B
diesel engines. The objective of this aspect of the final rule is to
set standards which, when met, will produce clean-burning diesel
engines that are safe and appropriate for use in the confined
environment of underground coal mines.
Like the proposal, the final rule's requirements for the gaseous
emissions of diesel engines are based on appropriate sections of
existing part 36 approval regulations for diesel engines. Experience
confirms that compliance with these regulations, which address fuel
injection adjustments and fuel-to-air ratios, produces engines that
operate without excessive gaseous emissions that can be harmful to
miners.
One commenter to the proposal suggested that the fuel injection
system on approved diesel engines be required to be fixed and sealed so
that it could not be changed. According to the commenter, sealing the
system would prevent unauthorized changes.
The final rule does not adopt this suggested change, as adjustments
to diesel engine fuel injection systems are necessary for maintenance
and to compensate for altitude. Adjustments such as these permit the
fuel-to-air ratio for diesel engines to be maintained at a level which
minimizes exhaust emissions.
The final rule does, however, adopt the proposed security
requirements to prevent unauthorized fuel injection system adjustments.
Fuel injection system adjustments are required to be changeable only
after breaking a seal, or by altering the injection system's design.
For example, a shim may be added or removed to change the fuel pump's
performance. These parts are supplied by engine manufacturers and must
be used in accordance with the engine's approval. For engines with
electronic fuel injectors, specialized computer interface equipment is
used to adjust the computer programming sequence. The programming
sequence must be installed by the engine manufacturer and is listed
with the engine approval documentation. After adjustments are made in a
fuel injection system, any seal removed must be replaced. Failure to
follow these procedures for adjusting a fuel injection system would
result in the engine no longer being in approved condition. Under
Sec. 75.1914(a) of the final rule, diesel engines used in underground
coal mines are required to be maintained in approved condition.
Consistent with a recommendation of the Diesel Advisory Committee,
the technical requirements for diesel engines also include undiluted
exhaust limits for carbon monoxide and oxides of nitrogen, both of
which have toxic properties which can be harmful to miners. The limits
set for these gases, which are determined when the engine is operated
at its maximum fuel-to-air ratio, are derived from existing
Sec. 36.26(b) and now-removed Sec. 32.4(f). As noted in the proposal,
applying these exhaust gas limits to diesel engines for use in outby
areas is new.
One commenter questioned why the proposal set the same undiluted
exhaust gas limits for Category A and B engines, except that the carbon
monoxide limit
[[Page 55420]]
was 0.30 percent for Category A engines, while the carbon monoxide
limit for Category B engines was set at 0.25 percent. This aspect of
the proposal, which is adopted without change in the final rule,
recognizes a difference in the test procedure between Category A and B
engines. As noted above, Category A engines must be designed to operate
safely in face areas and return air courses where methane may be
present. Thus, Category A engine testing is performed with 1.0 percent
methane injected into the intake air. The methane acts as additional
fuel in the engine, which affects the fuel-to-air ratio. This change in
fuel-to-air ratio increases emission levels, especially carbon monoxide
and oxides of nitrogen. Thus, the final rule technical requirements
permit a slightly elevated carbon monoxide level for Category A engines
during testing so as to avoid imposing an unnecessarily strict test
requirement for this class of diesel engines. The ventilating air
requirement, however, is based on the actual emissions measured during
testing.
The final rule also defines procedures to establish the ventilating
air quantities necessary to maintain the gaseous emissions of diesel
engines within existing required ambient limits. Emissions from both
Category A and Category B engines are diluted to the same ambient
levels when their ventilating air requirements are calculated. Like the
proposal and consistent with the recommendations of the Diesel Advisory
Committee, the final rule addresses this issue by requiring that a
ventilation rate be set for each engine model. Under the final rule,
this ventilation rate must appear on the engine's approval plate. The
ventilation rate, calculated under Sec. 7.88 of the final rule,
indicates the amount of air necessary to dilute carbon dioxide, carbon
monoxide, nitric oxide, and nitrogen dioxide to within allowable
levels. For consistency, the levels specified in the final rule are
those set by existing Sec. 75.322. These exposure standards are based
on the 1972 threshold limit values set by the American Conference of
Governmental Industrial Hygienists (ACGIH) and have applied to
underground coal mines for nearly 25 years. This aspect of the final
rule comports with the recommendation of the Diesel Advisory Committee
that gaseous diesel exhaust components not be treated differently from
contaminants generated by other mining sources. The final rule does not
adopt updated exposure standards at this time because this issue
remains in the rulemaking process for Air Quality standards.
The exposure levels adopted by the final rule for purposes of
calculating the ventilation rate for an engine will lead to lower
required air quantities for ventilating subpart E-approved engines, as
compared to engines approved under now-superseded part 36. This is
because engines previously approved under part 36 were required to
dilute oxides of nitrogen and carbon dioxide to levels lower than
currently specified by the threshold limit values (TLV's) in
Sec. 75.322. The ventilation rates set for engines under the final rule
will be more precisely related to current exposure standards. In
addition, Sec. 75.325(g) of the final rule revises the percentage of
the approval plate air quantity that is required when multiple units of
diesel equipment operate in the same air current. Finally, as discussed
elsewhere, the final rule is designed to produce an integrated system
of controls to protect miners from overexposure to harmful diesel
emissions.
Commenters generally accepted the value and purpose of setting a
ventilation rate for each diesel engine model. Knowledge of the
ventilation rate needed to control gaseous emissions to safe levels
will allow comparison of the efficiency and ventilation demands of
different engine models, and facilitate evaluation of their general
ventilation needs during use. One commenter, however, urged that the
gaseous ventilation rate for control of diesel engine exhaust gases not
be part of the approval process. According to this commenter, existing
ventilation and air quality standards are adequate.
The final rule adopts the requirements for determining the
ventilation rate necessary to dilute diesel engine exhaust
contaminants. Ventilation systems provide different quantities of air
at different locations in the mine. Knowing the ventilating air
quantities needed for diesel-powered equipment will allow the mine
operator to make informed decisions about equipment selection and
utilization and mine ventilation.
Other commenters, who acknowledged the purpose of establishing
ventilation rates for approved diesel engines, recommended for the sake
of clarity that the levels set for the gases be specified in the final
rule. In the proposal, MSHA had set these levels by reference to the
time weighted average (TWA) concentrations for the gases. The final
rule adopts this suggestion and the levels for carbon dioxide, carbon
monoxide, nitric oxide and nitrogen dioxide are specified in the final
rule. The levels in the final rule are identical to the levels in
existing Sec. 75.322, and MSHA intends that the levels in the final
rule conform with any levels that may ultimately be updated.
Specifically, if any of the levels for any of these contaminants are
revised as part of MSHA's Air Quality rulemaking, MSHA intends to
conform the levels in this section to any revised levels.
The proposed requirement for fuel deration received no comments.
The purpose of this requirement, which is adopted without change from
the proposal, is to ensure that the fuel-to-air ratio does not increase
due to the lower density of air at higher altitudes. Not correcting the
maximum fuel delivery on the engine for higher altitude operation
results in increased emission levels. The fuel injection rate
established during the approval may be required to be reduced when the
engine is used at a higher altitude.
Implementing a recommendation of the Diesel Advisory Committee, the
proposed rule also called for a particulate index to be set for
approved diesel engines. The particulate index specifies the quantity
of air needed to dilute the particulate generated by the engine to 1
milligram of diesel particulate matter per cubic meter of air. The
control of particulate matter in diesel engine exhaust was a
significant issue for the Advisory Committee. The Committee concluded
that whole diesel exhaust represents a probable risk for causing human
lung cancer, and recommended that MSHA develop a regulatory scheme to
monitor and control diesel particulate underground. The Committee did
not recommend an exposure level, but did urge that consideration be
given to what level of exposure to diesel particulate presents a health
risk to miners. MSHA is currently developing regulations, separate from
this rule, to address this issue.
The Diesel Advisory Committee also recommended that a particulate
index be set for engines so that the mining industry and MSHA could
compare the particulate levels generated by different engines in terms
of a ventilating air quantity. For example, if the particulate indices
for diesel engines of the same horsepower were established as 7,500
cubic feet of air per minute (cfm) and 12,000 cfm respectively, an
equipment manufacturer, mine operator, and MSHA personnel could use
this information, along with consideration of the type of machine the
engines would power and the area of the mine in which it would be used,
to make certain decisions. For example, a mine operator could use this
information when choosing an engine to roughly estimate an engine's
contribution of diesel particulate to the mine's total respirable
[[Page 55421]]
dust. MSHA would use this information when evaluating mine dust control
plans. Equipment manufacturers can use the particulate index to design
and install exhaust after-treatments.
The final rule retains the proposed requirement for a particulate
index to be set for approved diesel engines. Unlike the ventilation
rate set for each engine, the particulate index value will not appear
on the engine's approval plate. The particulate index, calculated under
Sec. 7.89 of the final rule, indicates what air quantity is necessary
to dilute the diesel particulate in the engine exhaust to 1 milligram
of diesel particulate matter per cubic meter of air. This information
will be available to the mining industry from the engine manufacturer
and MSHA.
Some commenters to the proposal objected to the use of a
particulate index to establish required ventilation air quantities for
diesel engines. These commenters noted that a diesel particulate
permissible exposure level has not yet been set and maintained that
suitable monitoring technology is not available for widespread field
use. These commenters also urged that control of diesel particulate in
underground mines be accomplished through a combination of measures,
including fuel requirements, equipment design, and controls such as
ventilation and equipment maintenance. The commenters recommended that
the particulate index not be part of the engine ventilation rate, and
concluded that such an index should be viewed as a guideline providing
useful information about diesel engines. The commenters further
suggested that additional evaluation be undertaken to determine
appropriate procedures for setting a particulate index.
The overall approach of the final rule is to control diesel
emissions in the underground mine environment through various
established methods, including those suggested by commenters. The
information provided by the particulate index is part of the multi-
level approach recommended by the Diesel Advisory Committee.
As explained above, the particulate index value determined for a
diesel engine is intended to provide useful information about diesel
engines, as the commenters suggested. In addition, the particulate
index value does not appear on the equipment's approval plate and
therefore is not considered in setting the engine's required
ventilation rate.
Section 7.85 Critical characteristics. Critical characteristics,
which are specified for all part 7-approved products, are those
features or specifications which, because of their importance to proper
operation of the equipment, must be inspected or tested on each unit
manufactured. The proposal called for inspecting or testing each diesel
engine to verify that the fuel rate is set to altitude, and the fuel
injection pump adjustment is sealed, if applicable. No comments were
received on this aspect of the proposal, and the final rule adopts the
proposal without substantive change. Instead of requiring the fuel rate
to be set to altitude, the final rule specifies that the fuel rate be
properly set.
As discussed elsewhere in this preamble, the rate of fuel delivery
to a diesel engine significantly affects its gaseous and particulate
emission. As noted earlier, correct adjustment of the fuel injection
pump is essential to the efficient operation of diesel engines.
Inspecting or testing the proposed critical characteristics for
diesel engines approved under part 7, subpart E reasonably ensures that
the performance and emission characteristics of production engines will
be equivalent to those of the engine tested for approval. As a result,
miners are protected against harmful exposure to diesel emissions.
No comments were received on this aspect of the proposal, which is
adopted by the final rule, with the change noted above.
Section 7.86 Test equipment and specifications. This section
adopts the measurement and evaluation methods for emissions from diesel
engines as described in ISO 8178-1. The final rule describes the
apparatus, or test cell, required for testing diesel engine
performance, and sets the specifications for operating this testing
equipment to perform steady-state tests for both gaseous and
particulate emissions.
The major components of a test cell are a dynamometer with engine
operating controls, and gaseous and particulate emission measurement
systems. This test cell is used to perform the test required by
Secs. 7.87, 7.88, and 7.89 of the final rule. Most engine testing
laboratories today have the equipment and meet the specifications
called for by ISO 8178-1 and the final rule.
The final rule's test cell requirements are substantially the same
as the proposed requirements, except that the specifications for the
testing apparatus and test conditions are revised to conform with ISO
8178-1. Commenters to the proposal did not direct attention to these
requirements, but did express concern about correlating the proposed
rule test requirements and Environmental Protection Agency diesel
engine tests, and recommended that the MSHA procedures conform to
internationally accepted test procedures. The adoption of the ISO 8178-
1 provisions eliminates this issue and is responsive to commenters'
concerns.
Like the proposal, the final rule also sets specifications for the
fuel to be used during testing of diesel engines. The proposed rule
would have required No. 2D diesel fuel with certain properties. A
uniform test fuel is important to obtaining repeatable test results and
test data that can be compared. Commenters did not direct their
attention to this aspect of the proposal, except that they generally
encouraged adoption of international standards to the extent possible.
The final rule revises the proposed requirements for diesel engine
test fuel to conform with the fuel requirements in Sec. 75.1901.
Section 75.1901 of the final rule specifies the use of diesel fuel
containing no more than 0.05 percent sulfur. Under this section, diesel
fuel used for engine testing must also be low in sulfur content. In
addition, the properties specified for test fuel conform with the test
fuel EPA requires for testing diesel engines that use low sulfur fuel.
Thus, the final rule will not require testing laboratories to acquire
special fuel to comply with the final rule.
The final rule also adopts the proposal that Category A engines,
which are intended for operation in areas of mines where concentrations
of methane gas could be encountered, be tested with 1.0 percent of
methane added to the engine's intake air. As noted above, this addition
to the ISO 8178 test procedure adopted by the final rule should present
no technical difficulties for manufacturers or third-party
laboratories. MSHA, however, will provide technical assistance for
setting up this aspect of the test procedure upon request.
Metering in 1.0 percent of methane to the intake air of Category A
engines replicates a foreseeable operating condition in underground
mines. In addition, methane gas acts as a fuel when it is aspirated
into a diesel engine, increasing its output of carbon monoxide and
oxides of nitrogen. These emission effects need to be accounted for in
determining the gaseous ventilation rate for Category A engines.
Section 7.87 Test to determine the maximum fuel-to-air ratio. As
noted earlier, the tests prescribed by this section are performed using
the test cell meeting the requirements of Sec. 7.86. Determining the
maximum fuel-to-air ratio for diesel engines is essential to
controlling harmful diesel engine emissions. Too rich a fuel and air
[[Page 55422]]
mixture produces engine exhaust with elevated levels of carbon monoxide
and oxides of nitrogen.
Under this section, engines are required to be operated at several
speed/torque conditions to determine the concentrations of carbon
monoxide and the oxides of nitrogen. Acceptable performance is achieved
when the levels of these exhaust gases do not exceed the limits set by
Sec. 7.84(b) of the final rule throughout the operational range of the
engine.
Commenters did not address the proposed test to determine the
maximum fuel-to-air ratio for diesel engines. The final rule adopts the
proposal without change.
Section 7.88 Test to determine the gaseous ventilation rate. The
test to determine the gaseous ventilation rate for a diesel engine is
required by the final rule to be performed using the test cell required
by Sec. 7.86. This test may be performed together with the test to
determine the particulate index required by Sec. 7.89.
The test required by this section measures the undiluted exhaust
gas concentrations of carbon monoxide, carbon dioxide, nitric oxide,
and nitrogen dioxide in the exhaust. These constituent gases of diesel
engine exhaust are potentially harmful to miners in the confined
environment of underground mines.
In accordance with Sec. 7.86, exhaust gas measurements must be made
at 8 specified points while the engine is operated at each rated speed
and horsepower requested by the approval applicant. For Category A
engines, 1.0 percent methane is added to the engine's intake, as
discussed above.
Like the proposal, the final rule specifies the calculations to be
performed using the results obtained from the test procedure. These
calculations produce a gaseous ventilation rate for the diesel engine.
As discussed above, the ventilation rate indicates the amount of
ventilating air necessary to dilute carbon monoxide, carbon dioxide,
nitric oxide and nitrogen dioxide to within permitted levels. The
ventilation rate for each approved Category A or B diesel engine will
appear on the engine's approval plate. Knowledge of the ventilation
rate needed to control gaseous emissions to safe levels will allow
comparison of the efficiency and ventilation demands of different
engine models, and their general ventilation needs during use can be
evaluated.
As discussed above, commenters generally accepted the value and
purpose of setting a ventilation rate for each diesel engine model. One
commenter urged that the ventilation rate not be part of the approval
process, while others supported the approach taken in the proposed and
final rules. These commenters, however, suggested that the levels for
the exhaust gases be stated in the final rule. The final rule adopts
this suggestion in Sec. 7.84(c).
Section 7.89 Test to determine the particulate index. Like the
other engine tests prescribed by the final rule, the test to determine
the particulate index for an engine is required by the final rule to be
performed using the test cell required by Sec. 7.86. As noted above,
this test may be performed concurrently with the test to determine an
engine's gaseous ventilation rate required by Sec. 7.88.
The test required by this section measures the amount of
particulate in the engine's exhaust when it is operated at eight
specified operating conditions. For Category A engines, 1.0 percent
methane is added to the engine's intake, as discussed above.
The proposed rule would have required that the particulate index be
determined using a different set of test points than those used to
determine the gaseous ventilation rate. The particulate index tests
were based on a cycle of 10 test points. In response to commenters'
suggestions that the particulate and gaseous emissions tests be
conducted using the same test cycle and internationally accepted test
procedures, the final rule adopts the same ISO 8178-4, 8-point test
cycle for both the particulate and gaseous emissions tests.
The Diesel Advisory Committee observed that whole diesel exhaust
represents a probable risk for causing human lung cancer. While
proposing no specific exposure level, the Diesel Advisory Committee
recommended control of diesel particulate in engines used underground
through a combination of measures, including equipment design.
Like the proposal, the final rule does not set a particulate limit
for engines. Instead, the final rule specifies the calculations to be
performed using the results obtained from the test procedures in this
section. From the calculations, a particulate index is derived. As
discussed above, the particulate index for an engine does not appear on
its MSHA approval plate. This information will be available, however,
from MSHA and the engine manufacturer.
Section 7.90 Approval markings. This section requires that each
approved diesel engine be identified with a permanent approval plate
containing certain information. Approval markings to identify equipment
appropriate for use in mining have been used for more than 85 years,
and are routinely relied upon by users of mining equipment as well as
state and federal inspection authorities.
The information required to be displayed on diesel engine approval
plates includes the MSHA-assigned approval number, together with the
engine's model number, ventilation rate, rated power, high idle
setting, and the altitude above which the engine must be derated.
Including these specifications on diesel engine approval plates gives
engine users convenient, immediate access to information important to
proper maintenance and operation of diesel engines.
Commenters directed little attention to this aspect of the
proposal, which is adopted without change in the final rule. Commenters
who objected to setting a ventilation rate for diesel engines as part
of the approval process repeated this concern with respect to the
requirement for the ventilation rate to appear on engine approval
plates. As discussed above, setting a gaseous ventilation rate for
diesel engines comports with the recommendations of the Diesel Advisory
Committee and provides diesel equipment users with information
important to protecting miners. Knowledge of the rate of ventilation
needed to control the gaseous exhaust emissions of a diesel engine
facilitates comparison of the efficiency and ventilation demands of
different engine models.
The other information required by the final rule to appear on an
engine's approval plate likewise provides engine users needed data. The
high idle setting informs maintenance personnel of the engine speed
appropriate for conducting several of the tests to be performed as part
of the engine's permissibility checklist. Together, an engine's
approval number, model number, and its rated power and speed facilitate
use of the manufacturer's maintenance procedures. The maintenance
procedures, along with the altitude above which the engine must be
derated, specify the adjustments which must be made to ensure that an
engine continues to operate in approved condition.
Burden hours required to make and mount MSHA approval plates are
assigned OMB control number 1219-0100.
Section 7.91 Post-approval product audit. This section
incorporates the standard audit requirement for part 7-approved
equipment, specifying that approval holders must make a diesel engine
available for audit by MSHA, at no cost to the Agency. The obligation
to
[[Page 55423]]
supply an engine for audit under this section arises only upon request
by MSHA, and is limited to no more frequently than once a year, except
for cause. Under existing Sec. 7.8(b), the approval holder may observe
any tests conducted under the audit.
Post-approval audits are a critical part of MSHA's quality control
program for approved equipment. By inspecting and testing an engine for
continuing compliance with its approval specifications, potential
problems can be detected and confidence in the approval process is
maintained. Since the inception of post-approval product audits under
part 7, MSHA has detected numerous discrepancies, which have been
effectively corrected.
Commenters directed no attention to this aspect of the proposal,
which is adopted without change from the proposal.
Section 7.92 New technology. This section is designed to
facilitate the introduction of new technology or new applications of
existing technology. It allows MSHA to approve a diesel engine that
incorporates technology for which the requirements of subpart E are not
applicable, provided that MSHA determines the engine is as safe as one
which meets the requirements of subpart E. To make this determination,
MSHA develops appropriate technical requirements and test procedures
when novel designs are submitted for approval. Experience with this
provision under existing regulations has shown that new innovations can
be effectively evaluated and made available for use in a prompt
fashion, thus serving the best interests of miners' safety and health.
Commenters supported this aspect of the proposal, stressing that
research and technological improvements in diesel engines can be
expected. The final rule adopts the proposal without change.
Subpart F Overview
Subpart F of the final rule amends existing part 7, which specifies
testing by the approval applicant or a third party. As an amendment to
the existing regulations, the general administrative provisions of
subpart A of part 7 apply to these new subpart F application
requirements.
Subpart F establishes design and performance requirements for MSHA
approval of ``diesel power packages'' for use in areas of underground
coal mines where permissible electrical equipment is required by
existing safety standards. A ``diesel power package'' is a diesel
engine, together with the attached safety components, such as flame
arresters, spark arresters, surface temperature controls, shut down
systems, and the exhaust cooling system that make a diesel engine
explosion-proof and reduce the engine's surface temperature to a safe
level. Like the proposal, the final rule requirements for diesel power
packages are largely derived from existing MSHA approval regulations in
part 36, which apply to diesel engines for use in gassy underground
mines. The final rule is also consistent with current MSHA practices
for coal mines using diesel-powered equipment and with the
recommendations of the Diesel Advisory Committee. The Advisory
Committee specifically recommended an approval program for diesel power
packages.
Commenters generally accepted the proposal for MSHA approval of
diesel power packages, recognizing the need for diesel-powered
equipment used in underground coal mines to meet critical
specifications and to be properly tested for safe operation in a
potentially explosive atmosphere. Some commenters directed their
attention to the effective date of subpart F, expressing concern about
the availability of commercial testing facilities. For the reasons
discussed below, the final rule does not adopt an extended phase-in
period. However, accommodations are made in the final rule to simplify
the implementation of testing in the private sector, and MSHA will
continue to perform diesel power package testing to subpart F
specifications for up to 3 years, pending the development of private
sector resources.
Other commenters recommended that diesel engine exhaust after-
treatment devices, such as particulate filters or catalytic converters,
be required as part of diesel power packages. These commenters also
suggested that the ventilation rate and particulate index set under
Secs. 7.88 and 7.89 of the final rule credit the use of such devices.
The final rule responds to these comments in part. Under the MSHA
approval program in subpart E, MSHA will evaluate exhaust gas and
particulate controls, provided these devices are integral to the engine
design and are part of normal production engines. The effectiveness of
such controls will also be considered in setting the engine's
ventilation rate and particulate index. This approach will ensure that
the controls are compatible with the engine and are effective. MSHA has
already approved, under existing regulations, engines which incorporate
techniques such as electronic fuel injection systems. Exhaust after-
treatment devices that are not part of an engine's design and
production have been developed which can reduce the particulate matter
in diesel engine exhaust. Also, catalytic converters are available
which can be added to engines to reduce the levels of some harmful
gaseous emissions. MSHA encourages the use of these devices, and under
existing regulations has approved, as safe, several power packages that
utilize catalytic converters and particulate filters. However, under
the final rule MSHA will not evaluate the effectiveness of these
exhaust after-treatment devices. Exhaust after-treatment devices
encompass a wide range of concepts that have demonstrated varying
degrees of effectiveness and reliability. The evaluation of these types
of after-treatment devices is beyond the scope of a part 7 approval
program.
For the same reasons, the final rule does not adopt a commenter's
suggestion that the particulate index for an engine be adjusted to
reflect the use of a diesel particulate filter. Also, the particulate
index for an engine is intended to be used by manufacturers and mine
operators as an aid for, among other things, selecting appropriate
after-treatment devices such as particulate filters. Therefore, under
the final rule the particulate index for an engine will indicate the
particulate contained in the raw engine exhaust.
Other aspects of the final rule will, however, recognize exhaust
after-treatment controls. The positive effects of catalytic converters
in lowering levels of harmful exhaust gases may be considered under
Sec. 75.325(i) for reducing the quantity of ventilating air required
where multiple pieces of diesel-powered equipment are in use. Also,
particulate filters can be effective in maintaining compliance with the
respirable dust standard set by existing Sec. 70.100.
During the course of this rulemaking, the question has been raised
as to whether the final rule should require that some or all diesel
engines be equipped with particulate filters. As noted above, MSHA
encourages the use of such filters and other emission controls.
However, the proposed rule did not raise this issue and MSHA received
only limited comment regarding the appropriate role of diesel
particulate filters. The final rule, therefore, does not require the
use of these filters. However, MSHA is currently developing a proposed
rule to address control of miners' exposure to diesel particulate. This
rulemaking will afford an opportunity to fully develop this issue.
Other commenters suggested that diesel engine cooling system
[[Page 55424]]
components, such as radiators, not be included as part of the approval
of diesel power packages so as to permit changes in cooling system
components to be made in the field without affecting the engine's
approval. The final rule does not adopt this suggestion. The inter-
relationship of the components in the cooling system of a diesel engine
is critically important to controlling power package surface
temperatures, which, when elevated, can lead to a fire. Consequently,
the engine cooling system components must be considered an integral
part of a diesel power package. This aspect of the final rule does not
prohibit field radiator changes, provided that the inter-relationship
of the engine's cooling system components is maintained in approved
condition.
A number of minor changes are made in Secs. 7.97, 7.98, 7.100,
7.101, 7.102, and 7.103 of the final rule to clarify the requirements
of these sections. Substantive changes to these sections are discussed
in the section-by-section discussion which follows.
Section 7.95 Purpose and effective date. The final rule's part 7,
subpart F approval requirements apply to diesel power packages intended
for equipment used in areas of underground coal mines where this
equipment is required to be permissible. The design, performance and
testing requirements of this section are effective November 25, 1996.
MSHA will begin accepting applications under new subpart F immediately.
To accommodate all interests, the Agency also will complete any in-
house part 36 safety component certification applications, or evaluate
such applications under new subpart F, at the applicant's choice. As
noted elsewhere in this preamble, the requirements for approved diesel
power packages in equipment used in underground coal mines become
effective in 3 years.
As noted above, several commenters urged that an extended phase-in
period of several years be included in the final rule. According to the
commenters, a phase-in period is needed to allow for the development of
competent third- party testing facilities, particularly with respect to
explosion-proof testing. Other commenters suggested that subpart F be
made effective immediately, so as to accelerate conformance to the new
requirements for the benefit of miners' safety.
A number of the final rule's test requirements can be performed
effectively with inexpensive, simple test equipment or facilities, or
with the power package installed in the mining equipment. For example,
the static pressure test required by Sec. 7.104 to evaluate the
structural integrity of power package components can be performed using
currently available hand pump devices. Likewise, explosion-proof
testing can be performed in inexpensive test chambers of relatively
simple design.
Nonetheless, MSHA recognizes that some testing capabilities are not
immediately available in the private sector, such as surface
temperature testing and exhaust gas cooling efficiency testing with
methane gas injection in the intake air. To facilitate the approval of
power packages and accommodate the needs of applicants, MSHA may be
consulted for simple alternative procedures which can be used to
provide the same results. In addition, MSHA will perform the tests
required by subpart F for diesel power package approval at its Approval
and Certification Center upon request by applicants. MSHA anticipates
providing these test services, for the fees set in accordance with 30
CFR Part 5, for up to 3 years, or until private sector testing
capability is available. MSHA reserves the right to determine when
competent private sector testing capability is available and to
discontinue MSHA testing.
Section 7.96 Definitions. In addition to the existing definitions
in Secs. 7.2 and 7.82, this section of the final rule sets out and
clarifies the key terms used in subpart F.
Commenters did not direct specific attention to this aspect of the
proposal. The final rule adopts the proposed definitions, with five
exceptions, adds two terms and definitions, and deletes three
definitions from the proposal which now appear in subpart E. These
changes are intended to add flexibility to the final rule and respond
to confusion among some commenters with respect to the substantive
requirements of subpart F.
The definition for ``exhaust conditioner'' has been revised to
remove the words ``corrosion-resistant.'' The requirement for the
exhaust conditioner to be made of corrosion-resistant material is
adopted from the proposal in Sec. 7.98(s)(4)(i). The definitions for
``exhaust system'' and ``intake system'' are revised to include the
phrase ``but is not limited to'', to recognize the use of components
not otherwise mentioned in the definitions for these terms. The term
``explosive mixture'' has been changed to ``flammable mixture'' to
conform with part 36, and the definition for this term has been
modified with the non-substantive change of removing the word
``violently.'' The definition for ``fastening'' has been modified for
the sake of clarity to remove the words ``device such as'' when
referring to bolts, screws, or studs. The term ``high idle speed/no
load'' has been revised to ``high idle speed.'' This is another non-
substantive change, since ``no load'' is specified in the definition of
the term. New definitions for ``dry exhaust conditioner'' and ``wet
exhaust conditioner'' are added to the final rule to more clearly
differentiate between the requirements for these systems. Under the
final rule, a dry exhaust conditioner is defined as a device which
cools exhaust gases without direct contact with water, such as a heat
exchanger. A wet exhaust conditioner is defined as a system which cools
exhaust gases through direct contact with water. Minor changes to the
definitions for ``step (rabbet) joint'' and ``threaded joint'' have
been made for the sake of clarity. The terms ``corrosion-resistant
material,'' ``idle speed/no load,'' and ``rated speed'' and their
definitions are deleted from subpart F. These terms are common to both
subparts E and F, and have already been defined in subpart E. Section
7.96 has been modified to incorporate the definitions of subpart E,
Sec. 7.82.
Section 7.97 Application requirements. This section is derived
from existing part 36 and requires that an application for approval of
a diesel power package contain sufficient information to document
compliance with the technical requirements of the final rule. The list
of information specified for inclusion in the approval application,
which is revised from the proposal in response to commenters and to
fully identify the engine and the fan blade material, is intended to
help applicants supply the data necessary for a prompt evaluation. The
final rule permits applicants to submit composite drawings. This
approach reduces paperwork, affords applicants flexibility in the
preparations of their drawings, and has proven to be effective in other
MSHA approval programs.
Like existing part 7 and other MSHA approval standards, the
documentation formulated in the application process under Sec. 7.97
forms the basis for MSHA's approval of a diesel power package. Approved
diesel power packages must be manufactured in accordance with the
specifications contained in the approval and, once put into service,
approved power packages must be maintained and operated within the
parameters set in the MSHA approval.
The paperwork hours in the approval application, including test
requirements, are assigned OMB control number 1219-0100.
Section 7.98 Technical requirements. This section of the final
rule sets specific technical requirements
[[Page 55425]]
for diesel power packages. Diesel power packages are intended for use
with Category A engines so that they can be operated safely and not
create a fire or explosion hazard. Consistent with the Advisory
Committee's recommendation that permissible diesel equipment be
required in areas of underground coal mines where permissible electric
equipment is required, the final rule's technical specifications
introduce many of the safety features currently required for
permissible electric-powered equipment.
Like the proposal, the final rule is derived largely from existing
technical requirements in part 36 for diesel-powered equipment intended
for use in gassy non-coal mines. The final rule also addresses the
hazard of combustible coal dust by specifying a maximum surface
temperature of 302 deg.F (150 deg.C). This is the same technical
requirement applied to permissible electric-powered equipment. Other
aspects of the final rule set specifications necessary to control
engine surface temperatures, sparking, and the passage of flame from
the exhaust system or components to the external atmosphere. Any of
these conditions could ignite an explosion or fire in the underground
coal mine environment.
Commenters generally accepted the proposed technical requirements,
which, as noted above, are based on long-standing regulations which
have been proven effective and workable. Commenters did, however, raise
several issues.
Some commenters sought wider tolerances for explosion-proof
enclosures in diesel power packages, citing experience in the United
States and Europe. These commenters directed their attention to the
proposed specifications for joints in engine exhaust systems, and
suggested that MSHA review the proposed specification of 0.004 inches
for maximum clearance for joints all in one plane.
The final rule retains this specification, which has proven to be
effective for decades. Commenters offered no basis for the
recommendation for a wider tolerance.
Other commenters suggested that electric starting devices for
diesel engines be prohibited. The proposed rule recognized the
conventional use of hydraulic, pneumatic or other mechanically actuated
starting mechanisms, but also retained the flexibility to evaluate
other means of starting under Sec. 7.107 of the rule concerning new
technology. This aspect of the proposal differs from the existing part
36 regulations from which this proposal was derived.
The final rule is intended to serve as a flexible set of
regulations that will continue to be workable over a period of years.
Throughout the final rule MSHA has adopted the more current practices
and, where appropriate, provides that alternatives may be developed
which are safe and effective. With this in mind, the final rule does
not expressly prohibit the use of electric starting devices for diesel
engines, adopting the proposal to permit MSHA to evaluate other
starting mechanisms. Such alternatives are subject to evaluation under
Sec. 7.107 and must be found by MSHA to be as safe as the pneumatic and
hydraulic starting mechanisms presently in use.
Some commenters asked for clarification of proposed paragraph (i)
with respect to the safety shutdown system required for diesel power
packages. The safety shutdown system is required to automatically shut
off the fuel supply and stop the engine in response to certain
dangerous engine conditions. MSHA intended in the proposal, and the
final rule clarifies, that the shutdown system must respond to both
high exhaust temperature and low water level in the engine's exhaust
conditioner. Either of these conditions can rapidly lead to a fire or
explosion hazard.
In addition, the final rule has been revised from the proposal to
cover other safety system shutdowns that may be installed by the
applicant. Section 75.342 requires methane monitors on some permissible
equipment, and the final rule requires permissible equipment to be
provided with a fire suppression system meeting the requirements of
Sec. 75.1911. Both of these standards specify that the diesel engine
must shut down when either an elevated level of methane is encountered
or when the fire suppression system is actuated. This requirement will
most likely be satisfied by a connection to the safety shutdown system.
The technical requirements of this rule now cover these additional
sensors.
Another commenter suggested that the safety shutdown system include
automatic brake lock-up to prevent diesel-powered equipment from
rolling. This aspect of a machine's safety is evaluated under the
existing requirements of part 36 and is not part of a diesel power-
package approval. Thus, the final rule does not adopt this suggestion.
The final rule adopts clarifying revisions in addition to changes
made in response to commenters. In several instances more precise
language is adopted to differentiate between requirements for wet and
dry exhaust conditioner systems. Proposed Sec. 7.98(d) has been revised
in the final rule to refer to ``nonmetallic rotating parts'' instead of
``fans'', to conform with other MSHA regulations. Paragraph (p)(2)(ix)
has been revised to require that the minimum thread engagement of
fastenings must meet the requirements of the explosion tests in
Sec. 7.104. This is a correction. This change conforms to paragraph
(p)(2)(viii), which requires both tests for acceptance of a minimum
thread engagement of fastenings less than \3/8\ inch. In addition,
paragraph (q)(7) of the final rule does not retain the proposed
requirement that a ``minimum of four fastenings'' be used for
explosion-proof joints. MSHA's experience shows that flange designs
with fewer than four fastenings have proven to be effective. Paragraph
(r)(5) has been revised to note that the opening for connection of a
gage to measure the intake vacuum must be closed by a plug or other
suitable device that is sealed or locked in place except when in use.
This language conforms to the language of part 36, and closing of this
opening is necessary to perform certain tests in this subpart.
Paragraph (s)(1) has been revised to require that the flame arrester
prevent the discharge of glowing particles, conforming it to the
requirement in part 36. Finally, paragraph (s)(5) has been revised to
note that the opening for connection of a gage to measure the
backpressure must be closed by a plug or other suitable device that is
sealed or locked in place except when in use. This language also
conforms to part 36, and is needed to perform some of the tests under
this subpart.
Section 7.99 Critical characteristics. Critical characteristics,
which are specified for all part 7-approved products, are those
features or specifications which, because of their importance to proper
operation of the equipment, must be inspected or tested on each unit
manufactured. The proposal focused on power package features essential
to preventing fires and explosions in the underground coal mine
environment, such as flame-arresting path clearances and the explosion-
proof integrity of the power package. Commenters did not direct their
attention to this aspect of the proposal, which is adopted without
change in the final rule.
Section 7.100 Explosion tests. This section describes the tests to
be performed on diesel power packages to ascertain whether they are
explosion-proof, as specified by the technical
[[Page 55426]]
requirements in Sec. 7.98. Like the proposal, the final rule is derived
from existing Sec. 36.46. Using an explosive mixture of natural gas and
air, or methane and air, the tests prescribed by the final rule
determine the power package's integrity in the event of an explosion
inside the intake or exhaust system. This could be caused by an engine
backfire during starting or ingestion of methane into the engine while
it is running. The prescribed tests determine whether flame arresters
and joints are capable of preventing propagation of the internal
explosion to the surrounding atmosphere. These tests also determine the
lowest water level in the exhaust conditioner that will act effectively
as a flame arrester, and the peak explosion pressures generated in each
segment of the intake and exhaust system. Excessive pressures may be an
indication of a design flaw.
Commenters did not raise issues regarding the proposed explosion
tests. However, the final rule includes one change from the proposal to
better ensure the ability of a diesel power package to withstand an
internal explosion, and another change to revise the speeds at which
dynamic tests are to be conducted. The final rule also includes non-
substantive changes for clarification and to conform the final rule
with existing MSHA regulations.
Paragraphs (a)(2) (v) and (vi) of the final rule specify an
internal peak pressure of 110 psig instead of the proposed 125 psig,
during power package explosion-proof testing. Excessive internal
pressures during explosion-proof testing indicate the potential for
failure of the diesel power package in use, with potentially
catastrophic results in the underground coal mine environment. Lowering
the peak pressure expected during explosion-proof testing recognizes
that diesel power package designs differ and that it is difficult to
select the optimum location for pressure measurements. When pressures
greater than 110 psig are measured during testing, the final rule
specifies redesign of the system to reduce the pressure or more
rigorous testing to verify the integrity of the system. Due to the
critical nature of this test, MSHA has adopted the same approach in its
explosion-proof test requirements for electric motors. The final rule
conforms these like requirements.
Paragraph (a)(2)(vii) of the final rule requires that dynamic tests
be conducted at two speeds--1800200 RPM and
1000200 RPM--instead of at rated speed and 50 percent of
rated speed specified in the proposal. The speeds set by the final rule
correspond to the speeds at which dynamic tests are performed
successfully at MSHA facilities. Also some test facilities may not be
capable of performing tests at the rated speed called for by the
proposal. This change is also reflected in paragraphs (a)(3)(iii) (A)
and (B).
For clarification, the final rule also adopts more precise language
to identify requirements which apply to wet exhaust conditioners,
distinguishing them from dry systems. The final rule also defines
natural gas that may be used in explosion-proof testing in a manner
that better recognizes the variables in the make-up of the hydrocarbons
found in natural gas. As a result, the final rule affords greater
flexibility for manufacturers and testing laboratories.
Section 7.101 Surface temperature tests. This section describes
the tests necessary to ascertain that diesel power packages will not
create a fire hazard in underground coal mines due to coal dust or
other combustible materials contacting hot surfaces. Like the proposal,
the final rule is derived from Sec. 36.48, and sets a maximum external
surface temperature of 302 deg.F (150 deg.C). The test protocol
simulates the operation of a diesel power package under heavy use
conditions. A note has been added to this section to alert the
applicant that this test may be done simultaneously with the exhaust
gas cooling efficiency test described in Sec. 7.102 of the final rule.
Commenters did not direct their attention to this aspect of the
proposal. The final rule is unchanged from the proposal, except for a
non-substantive clarifying change regarding wet exhaust conditioners
and the elimination of the reference to the use of natural gas. A
reference to natural gas, which consists primarily of methane, is
redundant. Instead, the final rule specifies the percentage of methane
to be added to the intake. Elimination of the reference to natural gas
also conforms this section to similar tests, which also determine
engine performance and which only specify methane, in subpart E of part
7.
Section 7.102 Exhaust gas cooling efficiency test. This section
describes the test procedures for measuring the temperature of the
exhaust gas at the discharge point from the exhaust conditioner.
Acceptable performance under this test is exhaust gases that do not
exceed 170 deg.F (76 deg.C) for power packages with a wet exhaust
conditioner, and 302 deg.F (150 deg.C) for a dry system. The proposed
and final rules are derived from existing Sec. 36.47 and address the
hazard of hot exhaust gases creating a fire or explosion hazard.
Commenters raised only one issue concerning this aspect of the
proposal, suggesting clarification of the different performance
requirements for wet and dry exhaust conditioners. The final rule
adopts this suggestion.
Section 7.103 Safety system controls test. This section is derived
from Sec. 36.47 and describes tests to evaluate the performance of the
safety shutdown systems required for diesel power packages. As
discussed above, these systems automatically shut down a diesel engine
in response to potentially dangerous conditions, such as overheating.
The tests prescribed introduce failure modes, such as loss of engine
coolant, and initiate the safety system. Acceptable performance is
achieved when the safety system automatically shuts down the engine
before the technical requirements for approval are exceeded.
Commenters recommended that the final rule more clearly delineate
the different requirements for wet and dry exhaust conditioners. The
final rule adopts this suggestion in paragraphs (a)(3), (a)(4), (b)(2),
and (b)(3).
Commenters also suggested that paragraph (a)(7)(ii) be amended to
include a caveat about the surface temperature of a turbocharger not
exceeding 302 deg. F (150 deg. C). This comment is not adopted because
the final rule addresses surface temperature control under Sec. 7.101
and requires that all external surfaces of power packages, including
turbochargers, not exceed 302 deg.F (150 deg. C). Paragraph (b)(7) has
been revised to accept starting mechanisms constructed of nonsparking
materials in addition to starting mechanisms that prevent the
engagement of the starter while the engine is running. This revision
conforms to Sec. 7.98(j)(1), which permits both options under the final
rule, as it would have under the proposal.
Section 7.104 Internal static pressure test. This section
describes tests to determine if the design of the intake and exhaust
system components of diesel power packages is structurally sound. The
prescribed tests specify internally pressurizing each segment of the
intake and exhaust system. The pressure required to be applied is four
times the maximum pressure observed in the tests performed under
Sec. 7.100, or 150 psig (5 psig), whichever is less.
Acceptable performance is based on an assessment of key points in the
intake and exhaust system, such as joints and welds, for evidence of
leakage or damage.
Commenters raised no issues with respect to the proposal. Paragraph
(b)(2)(vi) has been added to limit
[[Page 55427]]
permanent distortion of any planar surface of the diesel power package
to 0.04-inches/linear foot or less. This change conforms this
requirement to the same requirement applied to the explosion tests in
Sec. 7.100(b)(7).
Section 7.105 Approval markings. This section requires that each
approved diesel power package be identified with a permanent approval
plate inscribed with the MSHA approval number. If the power package
includes a wet exhaust conditioner that functions as an exhaust flame
arrester, the final rule requires that the approval plate also indicate
the grade limitation for the power package. This information is
important so that users are aware of the maximum grade on which the
exhaust conditioner will be effective as a flame arrester.
As noted elsewhere in this preamble, approval markings have been
used for more than 85 years, and are routinely relied upon by users of
mining equipment as well as state and federal authorities to identify
equipment appropriate for use in mining.
Another commenter suggested clarification of the proposal with
respect to the grade limitation for certain diesel power packages. The
final rule has been revised in response to this commenter to clarify
that the grade limitation applies to systems which use a wet exhaust
conditioner as a flame arrester. No grade limitation is appropriate for
power packages with a dry exhaust conditioner.
Burden hours required to make and mount MSHA approval plates are
assigned OMB control number 1219-0100.
Section 7.106 Post-approval product audit. This section
incorporates the standard audit requirement for part 7-approved
equipment, specifying that approval holders must make a diesel power
package available for audit by MSHA, at no cost to the Agency. The
obligation to supply a power package under this section arises only
upon request by MSHA, and is limited to no more frequently than one a
year, except for cause. Under existing Sec. 7.8(b), the approval holder
may observe any tests conducted under the audit.
Post-approval audits are a critical part of MSHA's quality control
program for approved equipment. By inspecting and testing a diesel
power package for continuing compliance with the specifications for its
approval potential problems can be detected and confidence in the
approval process is maintained. Since the inception of post-approval
product audits under part 7, MSHA has detected numerous discrepancies
which have been effectively corrected.
Commenters directed no attention to this aspect of the proposal,
which is adopted without change from the proposal.
Section 7.107 New technology. This section is designed to
facilitate the introduction of new technology or new applications of
existing technology. It allows MSHA to approve a diesel power package
that incorporates technology for which the requirements of subpart F
are not applicable, provided that MSHA determines the power package is
as safe as one which meets the requirements of subpart F. To make this
determination, MSHA develops appropriate technical requirements and
test procedures when applications for the approval of novel designs are
submitted. To provide confidence in the adequacy of the design, such
tests may be required to be performed by MSHA. Experience with this
provision under existing regulations has shown that technological
innovations can be effectively evaluated and made available for use in
a prompt fashion, thus serving the best interests of miners' safety and
health. Commenters generally supported this aspect of the proposal, and
the final rule adopts the proposal without change.
Section 7.108 Power package checklist. This section requires that
approved diesel power packages be accompanied by a description of the
features which must be checked and tests that must be performed to
ascertain that the power package is in approved condition. These
instructions, which are developed as part of the approval process, are
intended to aid power package users in keeping this equipment in safe
operating condition.
Commenters did not direct specific attention to this aspect of the
proposal, which is adopted without change in the final rule.
Part 7, Subparts G, H and I
The final rule does not adopt proposed subpart G to part 7, nor
further develops the advance notice of rulemaking published
concurrently with the proposal concerning subparts H and I to part 7.
Subpart G-approved power packages would have been required for
nonpermissible, heavy-duty diesel-powered equipment used in underground
coal mines. Subpart H would have established regulations for the
approval of fully assembled permissible diesel-powered machines, and
subpart I would have set requirements for the approval of fully
assembled nonpermissible, heavy-duty diesel-powered equipment. In lieu
of this approach, the final rule responds to the commenters who urged
that safety and fire protection features for nonpermissible diesel-
powered equipment be addressed in the Agency's part 75 safety standards
for underground coal mines. Existing part 36 is retained by the final
rule and revised to specifically apply to permissible diesel-powered
equipment for use in underground coal mines. Subpart H is not further
developed by the final rule.
In the proposal, subparts G and I were developed as an approach to
several of the Advisory Committee's concerns. In its deliberations, the
Advisory Committee considered the risk of fire on nonpermissible
diesel-powered equipment caused by hot surfaces igniting combustibles
such as hydraulic and lubricating oils, diesel fuel, and coal dust. To
address this hazard, the Committee recommended limiting engine surface
temperatures. Under the proposal, surface temperature controls and
other machine safety features for heavy-duty nonpermissible diesel
equipment would have been addressed in subparts G and I.
The Committee, however, also recognized the difficulty of applying
such controls to all nonpermissible diesel-powered equipment,
especially light-duty, utility equipment. The Advisory Committee,
therefore, recommended that a ``limited class'' of light-duty equipment
be identified for which less complex fire prevention measures would be
required, such as fire suppression systems which shut down the engine,
guarded drive shafts to prevent damage of fuel and hydraulic lines in
the event of a shaft failure, protection of the fuel tank and lines,
and proper design of the electrical system to prevent electrical arcs.
The proposal included these requirements for a ``limited class'' of
light-duty equipment in the part 75 safety standards for underground
coal mines.
The Advisory Committee also examined what additional features
should be included in the approval requirements for completely
assembled units of diesel-powered equipment. The Committee recommended
that MSHA develop an approval program that would emphasize other
equipment safety features which could be readily addressed by equipment
manufacturers. These features included safeguarding of the fuel system,
an exhaust gas dilution system, a fire suppression system, and
appropriate electrical and braking systems. As a completely assembled
machine, the interrelationship of these systems would be evaluated as
part of the approval process contemplated in the proposal under subpart
H.
A number of commenters objected to the approval of nonpermissible
diesel-
[[Page 55428]]
powered equipment. These commenters maintained that such an expansion
of MSHA's approval process would result in regulating diesel-powered
equipment differently than electric-powered equipment without
justification, and would present severe technical and economic
difficulties in meeting certain proposed requirements. The commenters
recommended that the final rule adhere to the long-standing regulatory
approach for electric-powered equipment, which sets performance-
oriented safety requirements for nonpermissible equipment in the
Agency's part 75 safety standards for underground coal mines. According
to the commenters, this approach would be responsive to the hazards
posed by diesel-powered equipment, and provide sufficient flexibility
to facilitate the introduction of new and safer technology.
In contrast, one commenter urged that all diesel-powered equipment
be approved as permissible, without regard to the equipment's use in
the mine. This commenter pointed out that diesel-powered equipment
presents different hazards than electric equipment, inasmuch as it
contains both a fuel source and an ignition source. The commenter
further maintained that permissible diesel-powered equipment receives
better maintenance than nonpermissible equipment, and explosive
accumulations of methane can be encountered anywhere in an underground
coal mine. This commenter noted that since 1969, 10 explosions occurred
in areas where nonpermissible equipment is permitted, and seven of
these explosions were caused by equipment that was not maintained in
permissible condition.
Another commenter agreed that heavy-duty nonpermissible equipment
should have approved engines and power packages to limit harmful
emissions from the engine and protect against the fire hazard presented
by hot engine surfaces. This commenter, however, objected to MSHA
approval of fully assembled nonpermissible machines as contemplated by
subpart I.
MSHA acknowledges that fire prevention and other machine safety
features can be successfully introduced for nonpermissible equipment,
without a formal approval program. This regulatory approach has been
effectively implemented through MSHA's part 75 safety standards for
underground coal mines as they apply to nonpermissible electric-powered
equipment. For example Sec. 75.518 provides fire protection by
requiring electrical system overload protection for nonpermissible
electric-powered machines. Section 75.523-3 provides a machine safety
feature by requiring automatic emergency parking brakes. Setting such
performance-based requirements for nonpermissible equipment maximizes
the flexibility afforded mine operators and manufacturers to minimize
the hazards of this equipment, and facilitates the introduction of new
technology for dealing with these hazards. For example, new heat
insulating materials have been developed since the publication of the
proposed rule, which can be used to control surface temperatures on
diesel-powered equipment.
To adapt this regulatory approach to nonpermissible diesel-powered
equipment, the final rule extends the proposal's safety requirements
for limited class equipment. Under the final rule, nonpermissible
diesel-powered equipment is not required to be approved by MSHA.
Instead, this equipment must comply with the final rule's safety
requirements in Secs. 75.1909 and 75.1910. These standards include
requirements for fire prevention and machine safety features such as
protection of hydraulic, fuel and electrical systems and adequate
brakes and operator controls.
Part 36
Existing part 36, previously known as schedule 31, has been in
effect since 1961. It sets approval requirements and specifications for
diesel-powered equipment used in ``gassy noncoal mines and tunnels''.
The final rule retains these existing regulations as the basis for
approval of diesel-powered equipment and, in lieu of further developing
subpart H, includes amendments which expand part 36 to apply to
equipment used in underground coal mines. Specifically, part 36 is
amended to afford manufacturers the option of incorporating into their
equipment part 7-approved power packages. Diesel-powered equipment with
approved power packages will be suitable for use in areas of
underground coal mines where permissible equipment is required. The
existing part 36 approval requirements for diesel-powered equipment
used in metal and nonmetal mines are unchanged by the final rule. Part
36-approved equipment with certified engines and safety component
systems will continue to be recognized for use in metal and nonmetal
mines where permissible equipment is required. MSHA will issue approval
numbers that differentiate between equipment for use in coal mines and
equipment for use in metal and nonmetal mines. Machines approved under
revised part 36 specifically for use in underground coal mines will be
identified with an MSHA approval number in a new sequence ``36c-''.
This will indicate that the equipment has been approved for use in
underground coal mines. A part 36 MSHA approval number in the sequence
``31-'' will indicate that the equipment has been approved for use in
metal and nonmetal mines.
These changes are responsive to a number of commenters who urged
that the existing part 36 regulations for the approval of diesel-
powered equipment be retained and continue to apply to equipment for
use in metal and nonmetal mines. In addition, the final rule expands
the scope of part 36, eliminating the need for separate approval
regulations for diesel-powered equipment for use in underground coal
mines as contemplated by subpart H in the proposal.
To retain part 36 and include the approval of diesel-powered
equipment for use in underground coal mines, the final rule re-titles
part 36 and eliminates references to ``gassy noncoal mines and
tunnels'' and related definitions. In addition, the application
requirements of Sec. 36.6 and design requirements of Sec. 36.20 are
revised to recognize the use of part 7-approved power packages, which
substitute for Secs. 36.21 through 36.26 (except Secs. 36.25(f) and
36.43 through 36.48).
The final rule also updates part 36 in several respects. Section
36.20, concerning the quality of material, workmanship and design, is
revised to eliminate an outdated reference to Sec. 18.24 of part 18,
schedule 2F. In its place, the final rule requires compliance with
Sec. 7.98 of the final rule, which provides structural and flame path
requirements for explosion-proof enclosures. This aspect of the final
rule reflects long-standing requirements for explosion-proof
components.
The definition of ``low-volatile hydrocarbon (diesel) fuel'' in
Sec. 36.2(i) is deleted by the final rule. This definition is outdated
and potentially confusing in context with Sec. 75.1901 of the final
rule, which specifies requirements for diesel fuel.
C. 30 CFR Part 70 Discussion
Section 70.1900 Exhaust Gas Monitoring
As outlined in the proposal, the Advisory Committee regarded the
health effects of diesel exhaust as a key area of concern. In its final
report, the Advisory Committee focused on two areas--exposure limits
and a sampling strategy to monitor the concentration of diesel exhaust
in miners' work environment.
[[Page 55429]]
The Committee recommended further research to develop information
about diesel particulate exposure levels at which health effects
accrue. The Committee also addressed gaseous diesel exhaust components,
concluding that suitable protection for miners would be achieved by
relying on coal mine air quality standards, either as they currently
exist or may be revised in the future. The Advisory Committee further
concluded that exposure limits for gaseous contaminants of diesel
exhaust should not be unique from the exposure limits set by the same
contaminants generated by other mining sources, such as blasting. The
Committee specifically recommended a periodic sampling strategy for
carbon monoxide, nitric oxide and nitrogen dioxide and sampling for
sulfur dioxide if diesel fuel containing more than 0.25 percent sulfur
is used. In addition, the Advisory Committee recommended a sampling
strategy which utilized return air course samples to trigger personal
exposure sampling. The Advisory Committee's recommendations served as
the basis for the proposed rule.
The proposed rule did not contain a diesel particulate exposure
standard. At the conclusion of their deliberations the Advisory
Committee recommended that the Secretary of Labor set in motion a
mechanism whereby a diesel particulate standard could be set, and that
the Secretary work in concert with the Bureau of Mines (BOM) and the
National Institute for Occupational Safety and Health (NIOSH) to
develop a sampling strategy and a program for its implementation.
Subsequent to those deliberations, MSHA has been working closely with
the BOM and NIOSH to develop methods for measuring diesel particulate
and for the development of criteria for reducing miners' exposure to
diesel particulate. In 1991, MSHA issued an advance notice of proposed
rulemaking seeking additional information for the development of a
rule. MSHA also held three workshops in 1995 that provided a forum for
mine operators, labor unions, trade organizations, engine
manufacturers, fuel producers, exhaust after-treatment manufacturers,
and academia, to present and discuss information about technologies and
approaches that can be utilized to limit the exposure of miners to
diesel particulate. MSHA is currently using the information obtained
from the advance notice of proposed rulemaking and the workshops to
develop a proposed rule for reducing miners' exposure to diesel
particulate.
The proposal generally followed the Advisory Committee
recommendations for sampling and permissible exposure limits. Under the
proposal, samples of carbon monoxide, nitric oxide and nitrogen dioxide
would be taken weekly in the immediate return airways of each split of
air where diesel equipment is used. When sampling results exceeded 50
percent of any permissible exposure limit set by the proposal, personal
exposure monitoring would have been required. If personal exposure
samples showed concentrations which exceeded 75 percent of the
permissible exposure standard, sampling would continue each operational
shift until, with 95 percent confidence, it was established that
exposure was at or below the permissible level.
Commenters to the proposed rule generally accepted the need for
regular sampling to evaluate miners' working conditions for the
presence of potentially harmful gaseous diesel exhaust components. A
number of commenters, however, noted that the proposed rule was too
focused on sampling, and gave inadequate attention to requiring
corrective action.
Some commenters recommended an alternative to sampling in return
air courses. These commenters suggested a personal sampling approach
keyed to the person in each mechanized mining unit likely to experience
the highest diesel exhaust exposure. This ``designated occupation''
would be identified in the mine's ventilation plan. According to the
commenters, this approach would recognize differences in mine
configuration and mining methods.
Some commenters considered the proposed action level for area
samples, set by the proposal at 50 percent of the permissible exposure
limit values for the gaseous emission components being measured, to be
reasonable. One commenter, in support of the action level concept,
noted that sampling in the immediate return air course would measure
the contribution of all diesel equipment on the mining section, thereby
yielding readings that would give reasonable assurance that miners
working on the section were protected.
Other commenters considered the 50 percent action level possibly
too low for mines with naturally occurring ambient levels of carbon
monoxide near the action level. Some of these commenters also foresaw
possible problems at mines operating near the 50 percent action level.
These commenters were concerned that an unnecessarily burdensome cycle
of area sampling followed by personal sampling could result. Commenters
also noted that the 50 percent action level could be raised because the
permissible exposure limits themselves include a safety factor. No
commenters offered data or specific support for a particular action
level.
Commenters also expressed concern about how effectively the
proposed sampling procedures would address variations in the
concentration of diesel exhaust in miners' workplaces. A number of
commenters suggested different strategies with more frequent samples to
better monitor the presence of the gaseous components of diesel
exhaust. Some commenters suggested special sampling to evaluate peak
exposure when, for example, equipment was operated under load. Other
commenters opposed such an approach, citing difficulties in determining
when peak conditions might occur. Another commenter recommended, in
addition to weekly samples in return air courses, weekly personal
samples of each diesel equipment operator, and at the same time samples
for at least two miners working inby all pieces of diesel equipment on
the same split of air. According to this commenter, the suggested
sampling strategy would yield better information about what diesel
exhaust control measure modifications may be needed. Other commenters
noted the dynamic nature of the underground mining environment, which
varies the concentrations of diesel exhaust in miners' workplaces.
These commenters recommended sampling be performed every shift in
miners' work areas to timely detect the onset of elevated levels of
diesel exhaust contaminants.
A number of commenters also noted that, in addition to sampling in
the immediate return air course, attention should be given to the area
of the section loading point. According to these commenters, diesel
exhaust contaminants are often elevated at this location due to high
engine loads at a single stationary point. Commenters also noted the
need to address situations when diesels are used in locations outby the
working faces. According to these commenters, construction projects can
involve significant diesel usage at some mines.
The proposed rule did not specify sampling methods for evaluating
the gaseous components of diesel exhaust. In the preamble discussion to
the proposal, however, MSHA made reference to electrochemical analyzers
and detector tubes as technology that could be used to determine
concentrations of the gases to be measured. Commenters did not suggest
specific sampling methods or object to those mentioned in the preamble
discussion. Some commenters, however, emphasized that the methods
chosen should not be highly technical in
[[Page 55430]]
nature. Several commenters urged that the task of sampling be something
miners generally could perform with proper training.
As discussed elsewhere in this preamble, the final rule as a whole
is designed to lay a foundation for the safe and healthful operation of
diesel equipment in the confined, potentially explosive underground
coal mine environment. To accomplish this objective, the final rule
sets standards for diesel engines, suitable for mining. For the
operation of this equipment, the final rule sets practicable standards
for the use of low sulfur fuel and for adequate ventilation and proper
maintenance of diesel equipment. These standards are intended to work
together as an operating system to create a more healthful and safe
working environment for miners.
Paragraph (a) of the final rule adopts a streamlined sampling
strategy that is keyed to this operating system approach. The
requirements of proposed Sec. 70.1900 have been revised in the final
rule to integrate sampling for gaseous components of diesel exhaust
with existing on-shift workplace examination requirements and to take
advantage of modern sampling instrumentation. The final rule also
incorporates by reference the threshold limit values (TLV's)
adopted by the American Conference of Governmental Industrial
Hygienists (ACGIH). These TLV's are also incorporated by
reference in MSHA's existing standards for exposure limits in
Sec. 75.322. The final rule retains the proposed action level concept
with some modifications responsive to commenters. However, the final
rule does not adopt the proposed requirement that area samples over the
action level trigger personal sampling. Instead, paragraph (c) of the
final rule requires corrective action to be taken immediately to reduce
gaseous diesel exhaust concentrations to or below the action level. The
final rule's sampling requirements are intended to provide a regular
and timely check on how the total operating system of diesel exhaust
control is working, with an emphasis on prompt corrective action.
Although the final rule does not require personal sampling,
existing standards regulate miners' exposure to harmful airborne
contaminants. These standards do not permit miner exposures over the
established TLV's incorporated in this section of the final
rule and in Sec. 75.322. MSHA enforces these standards during mine
inspections through personal and other sampling methods.
Like the proposal, paragraph (a) of the final rule specifies area
samples in the ventilation return airways of each working section where
diesel equipment is used, at a location which represents the
contribution of all diesel equipment on the section. This approach was
recommended by the Advisory Committee, and generally was supported by
the commenters. In response to commenters, the final rule also requires
samples in the area of the section loading point if diesel haulage
equipment is operated on the working section, and at the point inby the
last unit of diesel equipment on the longwall or shortwall face where
mining equipment is being installed or removed. Depending on the mining
system used, these are strategic locations in which to take area
samples to evaluate the overall effectiveness of the control measures
for diesel exhaust.
In addition, the final rule authorizes the MSHA district manager to
specify area samples at other strategic locations on a mine-by-mine
basis in order to accommodate circumstances which can result in
significant concentrations of diesel exhaust. This aspect of the final
rule responds to commenters' concerns about situations which can
involve significant diesel usage in areas outby the working face, such
as construction projects. The paperwork aspect of this provision
results in a minimally increased burden since existing Sec. 75.370 of
this chapter requires that all underground coal mines have ventilation
plans. Although this provision of the final rule is new, proposed
Sec. 75.390(b) would have required that the mine operator include
certain minimum ventilation quantities in the mine's ventilation plan.
Under the proposal, these minimum air quantities would have been
related to the number of diesel-powered units operating and the air
quantity necessary to control gaseous diesel emissions. Thus, this
final rule provision is consistent with proposed Sec. 75.390(b).
Monitoring of gaseous diesel exhaust components during the on-shift
examination required by existing Sec. 75.362 of this chapter makes
checks for diesel exhaust concentrations part of the workplace
examinations which have been historically conducted in the coal mining
industry. On-shift examinations are designed to detect hazards which
can develop during a working shift when normal mining operations are
underway. Such examinations include tests for methane gas accumulations
and oxygen deficiency, and determinations of air direction and
velocity. Tests for diesel exhaust gases can be readily made during the
on-shift examination by the same mine personnel. Currently, multi-gas
detectors are available and in use in a significant number of mines in
the industry which can sample simultaneously and directly read out
results for methane, oxygen, carbon monoxide and nitrogen dioxide.
Making checks of the mine's diesel exhaust control system part of the
existing practice of on-shift examinations minimizes the burden of
compliance with the final rule's sampling requirements. Under the final
rule, special staff and a separate diesel exhaust sampling schedule
should be unnecessary.
Sampling as part of the on-shift examination also increases the
frequency of diesel exhaust concentration monitoring from the proposed
weekly schedule, and responds to commenters who questioned the adequacy
of the proposal in this regard. The final rule's increased frequency of
sampling affords more timely and meaningful information about the
performance of the mine's overall diesel exhaust control system. Diesel
equipment is highly mobile and the mining environment changes rapidly
as mine development progresses. Monitoring each shift alerts the mine
operator to emerging problems with the control of diesel exhaust,
before miners are overexposed to harmful contaminants.
Consistent with existing Sec. 75.362 of this chapter, the final
rule also requires sampling to be performed by a certified person
designated by the operator. This aspect of the final rule is generally
consistent with the proposal as it requires that competent persons
perform the sampling, the results of which form the basis for important
decisions about miners' work environments.
Under the final rule, sampling would be required for two gaseous
components of diesel exhaust: carbon monoxide and nitrogen dioxide. The
final rule does not retain the proposal for sampling sulfur dioxide
when diesel fuel containing more than 0.25 percent sulfur is used.
Section 75.1901 of the final rule requires the use of low-sulfur fuel
at all times, rendering this aspect of the proposed rule unnecessary.
The final rule also deletes the proposed requirement for sampling
nitric oxide.
Both carbon monoxide and nitric oxide are produced in significant
quantities when diesel engines operate under load. Elevated carbon
monoxide is also indicative of engine faults such as misadjusted fuel
systems, failure to derate engines for altitude, or dirty air cleaners.
Conditions of use such as prolonged diesel engine idling can also
produce elevated levels of carbon monoxide. Catalytic converters,
designed to remove carbon monoxide
[[Page 55431]]
from the exhaust, work poorly under these conditions due to lower
equipment operating temperatures.
Nitric oxide concentrations generally do not reflect engine faults.
In addition, nitric oxide is readily converted to nitrogen dioxide in
the mine atmosphere, making representative measurement difficult under
the final rule's area sampling strategy. Also, in MSHA's experience the
TLV for carbon monoxide will be exceeded before the
TLV for nitric oxide. Sampling for nitric oxide, therefore,
is not retained in the final rule.
The final rule also requires sampling for nitrogen dioxide.
Nitrogen dioxide is readily detectable and potentially harmful to
miners. The TLV for nitrogen dioxide is 5 parts-per-million
(ceiling), which cannot be exceeded at any time. Therefore, the final
rule adopts the proposed requirement to sample for nitrogen dioxide.
The final rule addresses the collection of carbon monoxide and
nitrogen dioxide samples with performance-based requirements. In
response to commenters, the task of sampling is significantly
simplified. The sampling requirements also emphasize prompt
availability of sample results, consistent with the final rule's
emphasis on corrective action to protect miners from the risk of
overexposure.
Paragraph (b)(1) provides that monitoring of carbon monoxide and
nitrogen dioxide is to be performed in a manner which makes the results
available immediately to the person collecting the samples. This aspect
of the final rule recognizes that direct-readout sampling instruments
are now available that can measure carbon monoxide and nitrogen
dioxide. Use of these hand-held instruments requires no specialized
technical background so that persons may be easily trained to perform
this task. Mine-wide monitoring systems, with properly located sensors,
could also be employed to collect the required carbon monoxide and
nitrogen dioxide samples.
Paragraph (b)(2) of the final rule generally adopts the proposal,
and specifies that samples are to be collected by appropriate
instrumentation that has been maintained and calibrated in accordance
with the manufacturer's recommendations. These provisions establish
sound practices necessary for accurate sample results, while retaining
the flexibility for new instrumentation that may be developed in the
future.
Paragraph (b)(3) requires that samples be collected during periods
that are representative of conditions during normal operations. This
aspect of the final rule is consistent with the proposal and serves the
underlying purpose of the sampling requirements, which is to gauge the
performance of the diesel exhaust control system under normal operating
conditions. Like the proposal, the final rule does not prescribe
special requirements to measure the performance of the diesel exhaust
control system under peak load conditions. As some commenters noted,
determining when peak load conditions occur would be difficult to
predict. In addition, such an approach would increase the complexity of
the final rule unnecessarily.
Regular sampling during on-shift examinations will afford a
realistic picture of the performance of the diesel operating system. To
meet the requirement that samples be taken during periods that are
``representative of conditions during normal operations,'' MSHA intends
that tests for carbon monoxide and nitrogen dioxide be made when
diesel-powered equipment is being used as it typically is in the mining
process. Thus, for example, sampling is appropriate when diesel haulage
equipment is moving coal or diesel-powered roof bolters are installing
bolts.
Some commenters noted the need to monitor exhaust concentrations
during longwall moves with diesel-powered equipment, expressing concern
that moving the component parts of a longwall to a new block of coal
for mining can involve heavy usage of diesel equipment over the course
of multiple shifts. As a result, miners could be exposed to elevated
levels of diesel exhaust gases. The final rule addresses these comments
through the increased frequency of samples to monitor diesel exhaust
gases. On-shift examinations are required under Sec. 75.362 of this
chapter when longwall moves are being performed and, under the final
rule, tests of the concentrations of carbon monoxide and nitrogen
dioxide are required at the point immediately inby the last piece of
diesel equipment on the longwall or shortwall face. If these samples
indicate carbon monoxide and/or nitrogen dioxide concentrations greater
than the action level, immediate corrective action is required. This
approach protects miners through early detection of elevated
concentrations of diesel exhaust gases, and prompt adjustments to the
mine's diesel exhaust controls.
Paragraph (c) of the final rule is modeled after other MSHA
standards for potentially hazardous gases, such as methane, and
requires immediate corrective action when sample results indicate gas
concentrations exceeding the action level. This change in the proposal
is responsive to commenters who pointed out that the proposal gave
inadequate attention to corrective action. The final rule retains the
proposed action level concept tied to the TLV's for carbon
monoxide and nitrogen dioxide. The exposure limits incorporated are
those already incorporated in existing Sec. 75.322 of this chapter.
These exposure standards are based on the 1972 threshold limit values
set by the American Conference of Governmental Industrial Hygienists
(ACGIH) and have applied to underground coal mines for nearly 25 years.
This aspect of the final rule comports with the recommendation of the
Advisory Committee that gaseous diesel exhaust components not be
treated differently from contaminants generated by other mining
sources. The final rule does not adopt updated permissible exposure
standards at this time, as referenced in the proposal, because this
issue remains in the rulemaking process for Air Quality standards.
Under paragraph (c) of the final rule, the action level is set at
50 percent of the TLV's for carbon monoxide and/or nitrogen
dioxide for samples collected in the areas identified in paragraph (a).
As noted in the proposed rule, an action level is used to minimize the
risk that workers will be overexposed. An action level is not a
compliance limit for miners' exposure. Instead, an action level is
intended to provide a timely trigger for reviewing the mine's diesel
exhaust control system. Exceeding an action level under the final rule
is not, by itself, a violation.
The 50 percent action level concept is well-recognized in
industrial hygiene practice as an effective, practical screening tool
for minimizing the risk of workers' overexposure. This approach, based
largely on statistical considerations, was developed by the National
Institute for Occupational Safety and Health (NIOSH) for regulations
promulgated by the Occupational Safety and Health Administration
(OSHA), ``Leidel et al., NIOSH Publication No. 77-173.''. It is
designed to afford a single value trigger for simplicity of application
and to reduce exposure monitoring burdens. ``Patty's Industrial Hygiene
and Toxicology, 1994, p. 528.'' Based on the work of Nelson A. Leidel
and others, the 50 percent action level is considered a reliable
indicator that there is a low probability of worker exposures which
exceed the TLV linked to the action level.
The action level of 50 percent of the TLV's for carbon
monoxide and nitrogen dioxide is well-suited to the
[[Page 55432]]
purposes of this final rule, and will afford miners protection from
overexposure to potentially harmful diesel exhaust emissions. Samples
collected in accordance with paragraph (a) of this section will yield
results showing the concentration of diesel exhaust emissions in key
places under representative conditions on a regular basis. Applying the
50 percent action level to these routine sample results will account
for sources of variability affecting miners' exposure, such as the
diesel activity level, ventilation rates, and duty cycles. The action
level also provides a simple means of evaluating the status of the
mine's overall diesel exhaust control system. As discussed elsewhere,
this operating system approach to the control of diesel exhaust
emissions is a key underpinning of the final rule.
The final rule also permits adjustments to the 50 percent action
level on a mine-by-mine basis. Under Sec. 75.325(j) of the final rule
the MSHA district manager may approve an alternative action level in
the mine's ventilation plan. Ventilation plans are required for all
underground coal mines by existing standards under Sec. 75.370 of this
chapter. Under the final rule, any change in the 50 percent action
level must be based on the results of sampling which demonstrate that
miners' personal exposure will not exceed the applicable TLV.
Thus, a mine operator may show that a 60 percent action level, for
example, is appropriate for the miners working on a section. To do
this, the operator must demonstrate through sampling that miners
working on the section are not overexposed to diesel exhaust gases when
samples in the immediate return air course show that concentrations of
carbon monoxide and/or nitrogen dioxide are maintained at 60 percent of
the TLV. Based on this data, the 50 percent action level
could be revised, with the approval of the district manager. The higher
action level would be made part of the mine's approved ventilation plan
and, thereby, become a compliance requirement at the mine. If, with
experience, the revised action level was shown to be inappropriate,
changes would be made through the mine ventilation plan approval
process. Mine ventilation plans are required by existing standards to
be reviewed at least every six months.
The sampling necessary to demonstrate that the personal exposure of
miners would not exceed the TLV is not specified by the final
rule, recognizing that many approaches can be taken. For approval to
revise an action level, however, MSHA will require clear evidence that
a proposed change in an action level is appropriate. As discussed
above, the purpose of an action level is to trigger a review of the
mine's diesel exhaust control system before miners are overexposed to
harmful gases. As the action level is raised closer to the
TLV, the reliability of the action level as a timely warning
diminishes. Thus, MSHA does not anticipate approval of action levels
that provide a nominal margin of protection.
The final rule does not specify what corrective action is required
when an action level for carbon monoxide and/or nitrogen dioxide is
exceeded. Instead, this determination is to be made by the mine
operator, who is in the best position to implement changes appropriate
to the situation and sufficient to promptly return carbon monoxide and/
or nitrogen dioxide concentrations to or below the applicable action
level. Corrective action may involve addressing ventilation
deficiencies, controlling the number of diesel machines operating in an
area, or correcting engine faults. Elevated levels of carbon monoxide
and/or nitrogen dioxide may indicate that appropriate corrective action
is revision of the mine's ventilation plan. Modifying the mine's
ventilation plan integrates needed controls into the operating system
for the mine.
The final rule does not retain the proposed requirement to conduct
personal sampling when the action level for gaseous diesel exhaust
components is exceeded. Proposed Sec. 70.1901 therefore is not included
in the final rule. While the Advisory Committee recommended a two-
tiered approach of area sampling which could trigger personal sampling,
MSHA believes that the final rule's sampling strategy will better
protect miners. As discussed above, the sampling strategy adopted
focuses on the performance of the mine's control system for diesel
exhaust, rather than measurements of individuals' exposure levels. This
approach safeguards miners from overexposure by frequent testing for
gaseous diesel exhaust components in key areas, and establishing action
levels for initiating corrective action that responds to emerging
problems. In addition, MSHA mine inspections will include regular
checks on miners' exposure to harmful airborne contaminants, including
carbon monoxide and nitrogen dioxide, as part of determining compliance
with the TLV's in Sec. 75.322 of this chapter. MSHA's current
practice is to sample, at least annually, all diesel equipment
occupations on each mechanized mining unit. It is MSHA policy to also
sample half of the diesel equipment occupations in areas outby the
face. As a result, MSHA is confident that miners will be adequately
protected.
The final rule changes also respond to commenters who objected to
the proposed personal monitoring requirements as fostering excessive
sampling. In its guidance comments, the Office of Management and Budget
counseled that the criteria for personal monitoring had the potential
for an unnecessarily burdensome paperwork loop in which a mine would be
required to conduct area sampling one week and personal sampling the
next week. Other commenters also foresaw the potential for a cycle of
area sampling followed by personal sampling, particularly at mines with
naturally occurring high levels of carbon monoxide. These commenters
also objected to the proposal that when personal exposure monitoring
results indicate levels greater than 75 percent of the permissible
exposure limit, such sampling would be required to continue on each
operational shift until compliance was established with 95 percent
confidence. By focusing the final rule's sampling requirements on
monitoring the performance of the mine's diesel exhaust control system
and taking timely corrective action, this potential problem is
eliminated.
The proposed rule recordkeeping requirements were tied to MSHA's
proposed Air Quality standards in Secs. 72.200 (d), (e), (f) and (g) of
this chapter. Commenters objected to the proposal's reference to MSHA's
proposed Air Quality standards concerning exposure monitoring and
referenced the comments they had submitted on those proposed rules.
Under the proposal, the results of miners' personal samples were to be
maintained for 5 years and include personal identification information
as well as data about sampling location, duration, and results. The
proposed requirements also required a record of the corrective action
taken if miners' exposure readings exceeded the permissible limit. In
addition, the proposed rule set requirements for access to miners'
personal exposure records, provided miners or their representatives
with the opportunity to observe monitoring, and called for notification
of miners when samples indicate they have had exposures exceeding the
permissible limit.
In the Air Quality rulemaking, commenters objected to MSHA's
proposal that adjustments to calculations of exposure be made for novel
workshifts when a miner worked longer than eight hours. Commenters also
objected to mine operators having to take corrective action to reduce
[[Page 55433]]
exposures based on one sample showing overexposure. In addition,
commenters objected that it was burdensome to include the mine
operator's corrective action in exposure monitoring records. Other
commenters supported this requirement. These commenters further stated
that the period for record retention should be 30 years for
epidemiological purposes and to be consistent with the Occupational
Safety and Health Administration's general industry requirements.
For the reasons discussed above, the final rule re-focuses sampling
for the gaseous components of diesel exhaust on early detection of
diminishing performance of the mine's diesel exhaust control system. As
a result, personal samples are not required. Certain limited
recordkeeping is, however, necessary to support the final rule's
objective of tracking the performance of the mine's diesel exhaust
control system. To accomplish this objective with the least
recordkeeping burden, paragraph (d) of the final rule revises the
recordkeeping requirements of the proposal, conforming them to the
existing requirements for on-shift examinations. Under the final rule,
a record is required to be made of the results of samples taken under
this section which exceed the applicable action level for carbon
monoxide and/or nitrogen dioxide. Like the proposal, the data to be
recorded under the final rule include the location where the sample was
taken; the concentration of carbon monoxide and/or nitrogen dioxide
measured; and the corrective action taken to reduce the concentration
of carbon monoxide and/or nitrogen dioxide to below the applicable
action level. A record of the instrumentation used, which would have
been required under the proposal, has not been adopted in the final
rule, because this is not essential information under the sampling
scheme of the final rule.
This aspect of the final rule is intended to minimize recordkeeping
by requiring a record only when sample results are over the appropriate
action level. This information is key to an effective monitoring system
and provides essential data for assessing how the mine's diesel exhaust
control system is functioning.
For ease of administration by mine operators, the final rule
specifies that recordkeeping under paragraph (d) follow the same
requirements contained in existing Sec. 75.363 of this chapter. These
standards prescribe the recordkeeping requirements for hazardous
conditions found during a shift, including on-shift examinations.
Section 75.363 of this chapter requires that the record be kept in a
book maintained for the purpose on the surface of the mine, and that
the record be completed by the end of the shift. Section 75.363
requires that the record be made by the certified person who conducted
the examination, or a person designated by the operator. In the latter
case, the certified person must verify the record by the end of the
shift. Records made under Sec. 75.363 also must be countersigned by the
mine foreman or equivalent mine official by the end of the mine
foreman's or equivalent mine official's next regularly scheduled
working shift. These features of Sec. 75.363 emphasize the importance
of mine management using and responding to data about working
conditions in the mine.
Section 75.363 also recognizes the use of electronic recordkeeping
technology, provided it is made secure and not susceptible to
alteration. MSHA encourages the use of such systems to ease
recordkeeping burdens and facilitate analysis of this important
information.
The final rule does not retain certain proposed recordkeeping
requirements which related to personal exposure monitoring. These
include notification of miners if they are exposed over permissible
limits, the opportunity for miners to observe personal monitoring being
conducted, and access to personal exposure records by miners and their
representatives. Since personal sampling is not required by the final
rule, these provisions of the proposal are no longer appropriate.
The final rule does, however, make results from area samples
required by this section available for inspection by miners'
representatives and MSHA inspectors through Sec. 75.363 of this
chapter. This aspect of the final rule is consistent with the statutory
role of miners' representatives and facilitates meaningful mine
inspections. The retention period for the records required by paragraph
(d) is at least one year, through the existing requirements of
Sec. 75.363 of this chapter.
Paragraph (e) of this section of the final rule provides that
exhaust gas monitoring be conducted in accordance with Sec. 70.1900 as
of 12 months after the publication date of the rule. This compliance
deadline should provide mine operators with adequate time to implement
the requirements of this section, and corresponds to the 12-month
compliance deadline for the new ventilation requirements for diesel-
powered equipment in Sec. 75.325 of the final rule. Persons who are
qualified to take the required gas measurements should be available at
the mine, given the fact that air sampling for other gases, such as
methane, is already required.
D. 30 CFR Part 75 Discussion.
Section 75.325 Air Quantity
Diesel engines produce exhaust containing carbon monoxide, the
oxides of nitrogen, and particulate matter, presenting potentially
serious health risks to miners. Ventilation systems at underground coal
mines where diesel-powered equipment is operated must be designed to
dilute and carry away diesel exhaust contaminants, to ensure that
miners' exposure to contaminants is maintained within acceptable
limits. This portion of the final rule establishes minimum air quantity
requirements in areas of underground coal mines where diesel-powered
equipment is operated. These requirements recognize that effective mine
ventilation is a key component in the control of miners' exposure to
diesel exhaust contaminants.
Air quantity requirements for diesel equipment were proposed in
Sec. 75.390. Under the final rule these requirements have been
consolidated with the other air quantity requirements for underground
coal mines located in existing Sec. 75.325.
The final rule provides that the minimum air quantity required to
ventilate an individual unit of diesel-powered equipment is the
quantity listed on the equipment approval plate. The approval plate
quantity, which is calculated under Sec. 7.88 of the final rule for
each engine model, is the amount of air necessary to dilute carbon
monoxide (CO), carbon dioxide (CO2), nitric oxide (NO), and
nitrogen dioxide (NO2) to the levels set by existing Sec. 75.322
for those gaseous contaminants. This ventilation rate must be displayed
on the engine's approval plate. The approval plate air quantity must be
maintained: in any working place where an individual unit of diesel
equipment is being operated; at the section loading point during any
shift the equipment is being operated on the working section; in any
entry where equipment is being operated outby the section loading point
in areas of the mine developed on or after the effective date of the
final rule; and in any air course with single or multiple entries where
equipment is being operated outby the section loading point in areas of
the mine developed prior to the effective date of the final rule. The
district manager may also designate, in the ventilation plan,
additional locations where minimum air quantities must be maintained
for individual units of equipment.
[[Page 55434]]
In areas of the mine where multiple units of diesel-powered
equipment are operated, the final rule provides that the minimum air
quantity will be the sum of the approval plate air quantities of all of
the equipment. The air quantity must be maintained in the last open
crosscut of each set of entries or rooms in each working section; in
the intake, reaching the working face of each longwall; and at the
intake end of any pillar line. The final rule allows certain types of
equipment to be excluded from the multiple unit calculation for air
quantity, based on the fact that the emissions from those types of
equipment would not significantly affect the exposure of miners to
contaminants. The final rule also authorizes the district manager to
allow reduced air quantities in the ventilation plan for multiple units
of diesel-powered equipment, if the mine operator presents evidence
that justifies the reduction. Under this section mine operators are
also permitted to obtain district manager approval for an action level
other than the 50 percent level specified in Sec. 70.1900, if evidence
submitted by the mine operator supports such a change.
The Diesel Advisory Committee recommended that MSHA establish
minimum ventilating air quantities for areas of the mine where diesel-
powered equipment operates, and that these minimum quantities be
specified in the mine operator's ventilation plan. The Advisory
Committee further recommended that required air quantities be based on
the approval plate air quantities, with appropriate provisions made to
address multiple units of equipment in the same air course. The
Committee also concluded that allowances should be made for adjustment
to minimum air quantities, if operating experience and workplace
sampling indicate that such an adjustment is appropriate. Finally, the
Committee recommended that a particulate index be developed for each
piece of diesel-powered equipment and be reported on the engine
approval plate.
Under the proposed rule, the minimum quantity of air in any split
of air where an individual unit of diesel-powered equipment was
operated would have been the approval plate air quantity. The minimum
air quantity on any split of air where multiple diesel units were
operating would have been calculated using the sum of 100 percent of
the highest approval plate air quantity, 75 percent of the second
highest approval plate air quantity, and 50 percent of any additional
approval plate air quantities. This was referred to as the ``100-75-
50'' approach during the public hearings and throughout the rulemaking
process. Minimum air quantity requirements would also have applied when
face equipment was being installed or removed.
The proposed rule would also have established a minimum ventilation
quantity based upon the particulate index determined for each type of
diesel engine. The particulate index would have specified the quantity
of air needed to dilute the diesel particulate matter generated by the
specific engine to 1 milligram per cubic meter of air. In some cases
the minimum air quantity derived from the particulate index would have
been greater than the air quantity specified on the machine approval
plate.
A major concern of many commenters was the use of approval plate
air quantities in establishing ventilation requirements for both
individual and multiple units of diesel-powered equipment. A number of
commenters stated that the air quantities specified on engine approval
plates are not always necessary to dilute contaminants generated by the
equipment to permissible levels. Several commenters expressed concern
that the proposal represented a simplistic approach to complex issues,
given the great variety of ventilation systems in underground coal
mines.
Some commenters stated that determining minimum air quantities on a
mine-by-mine basis was more appropriate than the across-the-board
approach taken in the proposal. Most of these commenters stated that if
a mine's air quality is acceptable, air quantity should not be an
issue, advocating a performance-based approach. These commenters
believed that the final rule should give mine operators much more
flexibility than the proposal would in designing their ventilation
systems.
A number of these commenters recommended that approval plate
quantities be used only as a guideline for determining minimum air
quantities for diesel equipment, and that a number of other variables
be taken into account in determining the quantity of air needed to
dilute exhaust contaminants. Commenters stated that such variables
should include the minimum volume and velocity of air proposed by the
mine operator; the number of diesel-powered units operating on the
section; the equipment approval plate quantities; the duty cycles of
the equipment; and the duty cycles of equipment that is not typically
operating, such as equipment used for longwall moves.
Some commenters recommended the exclusion of certain equipment,
such as limited class equipment and equipment that is vented directly
into return air courses, from minimum air quantity calculations.
Commenters also suggested that administrative and engineering controls
designed to maintain contaminant levels within acceptable limits, as
well as respiratory protection practices implemented at the mine,
should be taken into account in calculating minimum air quantities.
One commenter pointed out that an engine's approval plate air
quantity is based on the worst point of the operational range of the
engine. The commenter further stated that this engine rating fails to
take into account a number of factors that affect the gaseous emissions
levels actually discharged into the mine environment, including the
equipment power package; the engine duty cycle; the mine's elevation;
the fuel used; and equipment maintenance.
Other commenters stated that the proposal would give no credit to
mine operators who used low emission technology, and that consideration
should be given to calculating approval plate quantities after rather
than before exhaust gases are treated. Other commenters stated that
approval plate air quantities were well below average ventilation
quantities currently provided in any given split of air.
The final rule does not incorporate the approach advocated by
several commenters for individual units of diesel-powered equipment.
Instead, paragraph (f) adopts the proposed requirement and provides
that the minimum ventilating air quantity where an individual unit of
diesel- powered equipment is operated is the approval plate air
quantity.
Although commenters are correct in stating that the goal of air
quantity requirements is to ensure that exhaust contaminants produced
by the diesel engine are diluted to within acceptable limits, thereby
preventing overexposure of miners, a pure performance-oriented
approach, based on sampling to determine whether contaminants are
within acceptable limits, is not the best way to achieve this goal.
Elimination of minimum air quantities and adoption of the performance-
based scheme advocated by some commenters would by necessity demand an
extensive and burdensome regimen of personal sampling to ensure that
miners are not being overexposed. In contrast, the mandatory minimum
ventilating air quantities in the final rule will give reasonable
assurance that contaminant levels are being adequately controlled,
while the sampling that an operator must perform has been minimized.
The
[[Page 55435]]
amount of air required by the approval plate quantity to ventilate a
diesel engine is a scientifically-based determination of the minimum
air needed to maintain gaseous contaminants, particularly NO2,
within acceptable limits and avoid overexposures of miners. The
sampling under the final rule confirms that the integrated system of
protections--diesel engines that are well maintained and effectively
ventilated--continues to function as intended.
The approach taken by the final rule is an effective method of
minimizing miners' exposure to unhealthful diesel emissions. As
explained above, the approval plate air quantity is derived from a
mathematical determination of the amount of air that is needed to
dilute CO, CO2, NO, and NO2 to the TLV's
established in existing Sec. 75.322, which have applied in underground
coal mines for the last 25 years. The TLV's for these
contaminants, with the exception of NO2, are time-weighted
averages, which means that the average concentration of the contaminant
over an 8-hour period must be within allowable limits, although the
levels of these contaminants may spike up significantly in excess of
the TLV in short excursions over the measurement period. In
contrast, the NO2 limit of 5 parts per million is a ceiling limit,
which means that concentrations of NO2 must never exceed the
TLV, even for a brief period of time. This is because
elevated concentrations of NO2 can be very toxic, and even short
exposure to high levels of NO2 can cause inflammation of the
lungs, possibly resulting in pulmonary edema and lung hemorrhaging. The
only external sign of NO2 poisoning is shortness of breath.
Sufficient dilution by adequate quantities of air of all contaminants,
and in particular of NO2, during the entire period that diesel-
powered equipment operates is therefore essential in protecting miners'
health.
It is important to note that the approval plate calculation assumes
total mixing of the exhaust gases in the ventilating air, and that
levels of exhaust gases that are higher than the TLV's will
likely occur close to the machine's exhaust, before the gases are fully
dispersed and diluted by the ventilating air. Essentially, this means
that the approval plate air quantity represents the best-case scenario
for contaminant dilution. The approval plate air quantity is therefore
the smallest amount of air that will ensure that contaminants are
within acceptable levels at all points in the engine's duty cycle.
It should also be noted that the oxides of nitrogen (NO and
NO2) have been the controlling gases for engine approval plate
quantities for the vast majority of diesel engines that have been
approved in the past. This means the approval plate quantity is
determined by the air needed to dilute those two gases; a lesser
quantity of air is sufficient to dilute the other gaseous contaminants
produced by the engine. Although NO does not have the same toxic
effects as NO2, it does convert to NO2 over time. As
mentioned above, sufficient dilution of NO2 is essential to
protect miners from its potentially severe effects.
The approval plate air quantity calculation takes into account the
worst operating point of a properly maintained engine tested under
laboratory conditions. Some commenters asserted that approval plate air
quantities were unnecessarily high, because the quantities were
calculated for the worst operating point of the machine, when the
machine generated the highest levels of gaseous contaminants. Although
commenters are correct in stating that the approval plate calculation
represents the air quantity needed to dilute contaminants at the point
where the engine produces the highest level of emissions, diesel engine
emission levels are high over a range of operating points. See, Report
of the Bureau of Mines, U.S. Department of the Interior, ``Relationship
of Underground Diesel Engine Maintenance to Emissions'' (December
1983). Contrary to the assertions of some commenters, the engine
approval plate quantity does not represent an unrealistically high
quantity of air, but is an accurate determination, based on testing, of
the ventilating air quantity needed to protect miners working in the
vicinity of the equipment over their working shift. Finally, as pointed
out by one commenter, the approval plate air quantity is calculated
using new engines, whose performance will likely degrade to some extent
over time, with the potential for increased emission levels, even if
the engines are well maintained.
The performance-based approach advocated by several commenters
could provide another method for determining minimum air quantities,
but, for the reasons stated earlier, would substitute a rather
intricate sampling process that would result in a determination that
essentially the same minimum air quantities are needed to ventilate the
equipment. Mandating approval plate quantities as the minimum air
quantities is not the only approach to ventilation of diesel-powered
equipment, but it is the most workable and practical.
The final rule does not adopt the suggestion of commenters who
advocated factoring in exhaust after-treatment in determining minimum
air quantities. The after-treatment technology currently available is
ineffective in reducing the oxides of nitrogen. Consequently, the gases
used to determine the approval plate air quantities for the vast
majority of diesel engines that have been approved cannot be controlled
by existing exhaust after-treatment technology. This recommendation has
therefore not been adopted in the final rule.
The locations where minimum air quantities must be maintained for
individual units of diesel equipment have been modified in the final
rule from what would have been required under the proposal. The
proposal would have required minimum air quantities for individual
units of equipment to be maintained in any split of air where the
equipment was being operated. A number of commenters disagreed with
this provision, stating that the term ``split'' was vague and
ambiguous, and did not adequately specify areas of the mine where
individual units of equipment were likely to operate and generate high
levels of diesel exhaust contaminants. Commenters also identified outby
areas and section loading points as locations where diesel exhaust
levels tended to be a particular problem and where additional
ventilating air was needed. Several commenters stated that it was
essential to have adequate ventilation across the mine's dumping points
to ensure that diesel emissions are swept out of the area. These
commenters stated that the rule should also address outby operation of
diesel-powered equipment, because excessive diesel emissions occur in
idled areas of the mine and during non-production times, when less air
is typically required for ventilation because dangerous levels of
methane tend to be less of a problem during those periods. Other
commenters were of the opinion that the rule should not designate
locations where minimum air quantities must be maintained, and
supported determining these locations on a mine-by-mine basis.
In response to commenters, the final rule does not adopt the
proposed requirement that the air quantity for individual units of
equipment be maintained in any ``split'' where the equipment was being
operated. Instead, paragraphs (f)(1) through (f)(5) list the specific
locations where the minimum air quantity must be maintained, and
include those locations identified by commenters where diesel equipment
is typically inadequately ventilated and
[[Page 55436]]
where levels of exhaust contaminants are likely to be high. These
locations include any working place where the equipment is being
operated; at the section loading point during any shift the equipment
is being operated on the working section; in any entry where equipment
is being operated outby the section loading point in areas of the mine
developed on or after the effective date of the final rule; in any air
course with single or multiple entries where the equipment is being
operated outby the section loading point in areas of the mine developed
prior to the effective date of the final rule; and at any other
location required by the district manager and specified in the approved
ventilation plan.
Paragraph (f)(1) provides that the minimum ventilating air quantity
for an individual unit of diesel-powered equipment must be maintained
in any working place where the equipment is being operated. This
responds to commenters' concerns and clarifies the intent of the
proposal, which would have required that the minimum air quantity be
maintained in the ``split'' where the equipment operates. As discussed
above, a number of commenters did not consider the term ``split'' to be
sufficiently descriptive, and the final rule has been revised in
response. Under the final rule required air quantities must be
maintained in the ``working place,'' which is defined in existing
Sec. 75.2 as ``The area of a coal mine inby the last open crosscut.''
This location is designed to address ventilation of an individual unit
of diesel-powered equipment that is working at an inby location, near
the face.
Paragraph (f)(2) adds the specific requirement that the minimum air
quantity for an individual unit of equipment be maintained at the
section loading point during any shift that the equipment is being
operated on the working section. This provision responds to commenters
who singled out loading points as one of the locations where excessive
levels of diesel contaminants were a particular problem. Commenters
pointed out that the ventilating air quantities at these locations were
frequently insufficient to dilute exhaust contaminants and protect
miners from unhealthful levels of exhaust gases. Because different
types of equipment move in and out of a section loading point on a
regular basis, the minimum required air quantity will be the greatest
approval plate quantity among all of the diesel-powered equipment that
is operated at the loading point during the shift. This will ensure
that miners are protected from overexposure to contaminants at all
times during the shift, regardless of which unit of diesel equipment is
at the loading point.
Paragraphs (f)(3) and (f)(4) have been added to the final rule to
address the concerns of those commenters who stated that minimum
ventilation requirements should apply to diesel-powered equipment that
is being operated in outby areas. These two provisions, one of which
applies to areas of the mine developed before the effective date of the
final rule and the other which applies to areas developed on or after
the effective date, recognizes that the ventilation system design at
some mines with multiple common haulage entries would make it
difficult, if not impossible, to maintain minimum air quantities in a
single entry. Consequently, the final rule allows the minimum air
quantity to be maintained in the air course rather than in a single
entry, in areas of the mine developed before the effective date of the
final rule. In areas of the mine developed on or after the effective
date, the minimum air quantity must be maintained in a single entry.
This means that mines with multiple common entries that use diesel
equipment must alter their approach to future mine development no later
than the effective date of the final rule.
This two-pronged approach to ventilation of outby diesel equipment
recognizes that the location and direction of required air quantities
have an impact on how effectively the air will dilute diesel engine
emissions. Air that is coursed directly over diesel equipment will
dilute contaminants more effectively than air of the same volume and
velocity that is dispersed over a wider area. Consequently, providing
the air quantity in a single entry rather than over multiple entries is
a more desirable method of ventilation. However, this approach also
takes into account that a number of mines would be unable to comply
with the location requirements of (f)(3) in areas that have already
been developed, without significant capital expenditures and
substantial disruption of mining operations. This aspect of the final
rule therefore strikes a balance between the concerns of commenters
regarding adequate ventilation of diesel equipment operated in outby
areas, and the economic infeasibility of a complete overhaul of areas
of the mine that have already been developed.
It should be noted that Sec. 75.1907 of the final rule does not
require diesel equipment used in outby areas to have an engine approved
under subpart E of part 7 of the final rule until 3 years after the
publication date of this rule. During this transitional period,
equipment with unapproved engines that do not have an approval plate
will not be subject to the minimum air quantity requirements of the
final rule. However, mine operators are under a continuing obligation
to ensure that air contaminants are maintained within the limits
established in Sec. 75.322, and diesel-powered equipment must be
ventilated with sufficient quantities of air to prevent overexposure of
miners.
Paragraph (f)(5) has been added to the final rule to give the
district manager the authority to require other locations where minimum
air quantities for individual units of equipment must be maintained.
These locations must be specified in the ventilation plan. This
provision has been added in response to commenters who were concerned
about inadequate ventilation in areas where diesel-powered equipment
was operating, other than those locations specified in paragraphs (f)
(1) through (4). These locations could include, for example,
underground repair shops, permanent fuel storage facilities or
temporary fuel storage areas, or construction sites where diesel-
powered equipment is regularly operated and where minimum air
quantities are needed to keep contaminant levels within acceptable
limits.
The final rule adopts the proposal's approach of using the engine
approval plate air quantity to determine the minimum air quantity in
areas where multiple units of diesel-powered equipment are being
operated. Paragraph (g) provides that the minimum ventilating air
quantity where multiple units of diesel-powered equipment are operated
on working sections and in areas where mechanized mining equipment is
being installed or removed, must be the sum of 100 percent of the
approval plate quantities for all of the equipment. As mentioned
earlier, this is a change from the 100-75-50 percent approach of the
proposal.
The final rule, like the proposal, also specifies certain equipment
that may be excluded from the calculation of minimum air quantity, and
also permits a mine operator to obtain a reduction in the required
minimum air quantity for multiple units if sampling evidence
establishes that a lesser ventilating air quantity will maintain
continuous compliance with the TLV\'S in Sec. 75.322.
Several commenters advocated that approval plate air quantities be
used only as guidelines for ventilation of multiple units of equipment,
for the same reasons outlined in the discussion of ventilating air
quantities for individual units of equipment. These commenters stated
that there were a
[[Page 55437]]
number of variables that must be considered in establishing ventilation
for diesel equipment, and advocated determining minimum air quantities
on a mine-by-mine basis.
Some commenters were opposed to the 100-75-50 approach, stating
that it would not adequately protect miners. These commenters took
issue with the assumption that multiple units of diesel-powered
equipment could not be operating at their worst point, i.e., generating
the highest levels of emissions--simultaneously. Commenters also
pointed out that the 100-75-50 approach assumed that engines perform at
a consistent level from the day they are purchased until the end of
their useful life, and advocated that the sum of 100 percent of the
approval plate air quantities be used instead as the minimum
ventilation quantity.
The final rule, like the proposal, specifies that engine approval
plate quantities are the minimum ventilating air quantity for diesel-
powered equipment. The approval plate quantity is required for multiple
units for the same reasons that it is required for individual units: it
is an accurate calculation of the amount of air that is needed to
dilute gaseous diesel exhaust contaminants to acceptable levels.
However, the final rule, like the proposal, allows mine operators to
seek reductions in the required air quantities if they are able to
demonstrate that contaminant levels will be kept within required limits
at reduced ventilating air levels. This provision recognizes that, as
stated by commenters, there may be variables of mine design, equipment
operation, or ventilation in areas where multiple units operate that
may result in less air being needed to keep air quality within
healthful limits. For example, if the diesel machines on a section are
not operated so that all machines are producing maximum emissions
simultaneously, reduced minimum air quantities may be appropriate.
The final rule does not adopt the 100-75-50 approach, in response
to commenters' concerns that it would not provide adequate protection
for miners, and for several other reasons. First, the 100-75-50 formula
was designed to account for differences in duty cycles among the
equipment, since the approval plate air quantity is based upon the
worst point of the operating range of the equipment relative to gaseous
emissions. The 100-75-50 approach assumed, as has been pointed out by
commenters, that multiple units of equipment would not have been
operating at their worst points at the same time. As discussed above,
although the approval plate air quantity is calculated for a worst case
engine operating point, research has shown that engines generate high
levels of contaminants over a range of engine operating points. The air
quantity available on the section should be sufficient to control the
engine emissions under all conditions.
The 100-100-100 approach also recognizes that approval plate air
quantities will be calculated differently under part 7 than they have
been under part 36, prior to the promulgation of this final rule. As
discussed in the preamble to subpart E of part 7, an engine's approval
plate air quantity under the final rule will be determined by the
amount of air needed to dilute contaminants to the TLV's in
Sec. 75.322. Up until now, approval plate quantities have been
determined under part 36 based on the amount of air needed to dilute
contaminants to 50 percent of the TLV's that were in effect
when part 36 was first promulgated in 1961. Although the levels to
which CO and NO2 must be diluted remain the same under the final
rule, the dilution levels for NO and CO2 are twice as high.
Consequently, less air will be needed to dilute these two gases to the
higher levels, and the approval plate quantity will be lower for most
if not all engines. However, the approval plate quantity will now
directly correlate to existing TLV's. It follows that 100
percent of the approval plate quantity, rather than some fraction
thereof, must be provided to adequately dilute the gaseous diesel
engine contaminants.
Approval plate quantities determined under the final rule may also
be slightly lower than before under old part 36, as a result of the
revision in part 36 that requires engines to be tested with 1.0 percent
methane injected into the engine air intake, rather than the current
1.5 percent. Because injection of methane into the engine increases
engine emissions, the lower concentration of methane used under the
final rule will result in lower emissions and will require a lower
quantity of air to dilute.
Because of these factors, the 100-100-100 calculation for multiple
units of equipment will not result in minimum air quantities that are
significantly greater than air quantities currently required in
ventilation plans using the 100-75-50 method of calculation. In fact,
in some cases, the air quantity required for multiple units may be less
than what was required before, depending on the diesel equipment that
is being operated.
Under the proposal, air quantities in excess of the 100-75-50
calculation for multiple units of equipment would have been required
when the particulate index established for the equipment indicated that
a greater air quantity was needed to maintain diesel particulate levels
within acceptable limits. The particulate index indicates the quantity
of air required to dilute particulate emissions from that specific
engine to a concentration of 1 milligram per cubic meter of air. The 1
milligram value was chosen to make the use of a diesel particulate
permissible exposure limit with an engine's particulate index a matter
of simple multiplication, and is not meant to be an indicator of the
level of any diesel particulate standard that may be set by MSHA in the
future.
Under the proposal, MSHA intended to apply the particulate index in
two phases, before and after the setting of a diesel particulate
standard. Before the promulgation of a standard, MSHA intended to take
an engine's particulate index into account in approving minimum air
quantities in a mine operator's ventilation plan by estimating the
contribution of diesel particulate to the total respirable coal mine
dust concentration. After the promulgation of a diesel particulate
standard, the minimum air quantity would be determined using the
particulate index to calculate the air quantity needed to dilute the
particulate concentration to whatever level was required.
A number of commenters stated that, because MSHA has not yet
established a permissible exposure limit for diesel particulate, a
requirement for increased air quantities based upon a diesel
particulate index was inappropriate. Other commenters supported the use
of a particulate index as a point of comparison among different diesel-
powered engines, but they were strongly opposed to the use of the index
to require minimum air quantities. Other commenters stated that
accurate measurement of diesel particulate is not possible, because
diesel particulate matter is indistinguishable from other respirable
coal mine dust. One commenter stated that the particulate index fails
to take into account that the diesel engine is itself only one factor
in how cleanly the machine operates as a whole. This commenter
recommended that other factors be considered, including the
effectiveness of water scrubbers, dilutors, catalytic convertors, and
particulate traps or filters, any one of which could significantly
reduce diesel particulate emissions.
Although MSHA is currently developing a proposed rule to control
miners' exposure to diesel particulate, MSHA agrees with commenters who
believe that the use of the particulate
[[Page 55438]]
index for determining minimum ventilation requirements would be
premature in the absence of a standard for diesel particulate. The
final rule therefore does not adopt the proposal's requirement for
increased air quantities based on a diesel engine's particulate index.
However, MSHA will still calculate an engine's particulate index as
part of the approval process. As was true under the proposal, the
particulate index will be determined under part 7 of the final rule.
The particulate index for the engine will be reported in the approval
letter that MSHA sends to the engine manufacturer notifying the
manufacturer that the engine has been approved. A copy of this letter
also accompanies the equipment when it is purchased by the mine
operator. The particulate index for all MSHA-approved diesel engines
will also be included on MSHA's list of approved products, which is
issued on a regular basis to the individuals and companies on MSHA's
mailing list. MSHA anticipates that, until a diesel particulate
standard has been set, mine operators and machine manufacturers will
use the engine particulate index in selecting and purchasing engines.
During this time mine operators may also use an engine's particulate
index to roughly estimate the engine's contribution to the mine's
levels of total respirable coal mine dust.
Under the proposal multiple units of equipment would have been
required to be ventilated by specified minimum air quantities in the
last open crosscut of each working section or in the intake splits of
longwall sections. The proposed rule would also have required minimum
air quantities to be maintained when face equipment was being installed
or removed.
One commenter stated that air on a dieselized section should be
coursed throughout the section and should not be concentrated in the
last open crosscut. This commenter recommended that the total intake
air quantity going into the section intake and the total return air
quantity leaving the section should be measured. Another commenter
stated that air measurements are more accurate in the immediate return
of each split, rather than at the last open crosscut.
Several commenters pointed out that too much air across the face
area was detrimental to the effective operation of respirable dust
scrubbers on continuous miners. Several commenters identified longwall
moves as periods when miners were exposed to high levels of diesel
exhaust, due to the increased use of diesel-powered equipment on the
sections during these periods and the increased diesel engine loads.
These commenters stated that during longwall moves the exhaust from one
diesel machine would be ``rebreathed'' by another diesel machine,
resulting in a doubling of carbon monoxide levels.
Paragraphs (g)(1) through (g)(3) of the final rule set forth the
specific locations where minimum air quantities must be maintained
where multiple units of diesel-powered equipment are operating. Under
the proposal, as described above, minimum air quantities would have
been required in the last open crosscut of each working section or in
the intake splits of longwall sections.
The final rule essentially adopts the approach of the proposal,
although the term ``split'' used in the proposal has not been adopted
in the final rule because, as explained in the discussion under
paragraph (a) of this section, commenters considered the term ``split''
to be vague and ambiguous. The final rule provides more specific
description of the locations where air quantities must be maintained,
although the location requirements themselves are essentially the same
as they would have been under the proposal. Paragraphs (g)(1) through
(g)(3) of this section require the minimum air quantity in working
sections to be maintained: in the last open crosscut of each set of
entries or rooms in each working section; in the intake, reaching the
working face of each longwall; and at the intake end of any pillar
line.
The final rule does not adopt the suggestion of commenters that air
measurements be taken at locations other than those specified in the
proposal. The recommendation that the total intake air quantity
entering a section and the total return air quantity leaving a section
be measured has not been adopted because this method of measurement
will not provide an indication of the air quantity that is actually
reaching the working section. The air could be short-circuited before
it reaches the diesel machine, but still be measured as part of the
return air quantity. Further, the recommendation that air measurements
be taken in the immediate return of each split, rather than at the last
open crosscut, has not been incorporated into the final rule because
measurement at that location will give a less accurate indication of
the air that is actually ventilating the diesel equipment. Finally, the
measurement of air quantities at the last open crosscut under the final
rule is also consistent with air measurement requirements currently in
most underground coal mine ventilation plans.
The final rule does not respond to commenters who stated that too
much air across the face area could have a negative impact on the
effectiveness of respirable dust scrubbers on continuous miners. While
it is true that increased air quantities could in some cases have an
adverse effect on dust scrubber effectiveness, this impact must be
balanced against the need to control harmful diesel exhaust
contaminants. There are other dust control technologies that are
available to supplement dust scrubbers if the need arises.
In response to the many commenters who expressed concern about
exposure of miners to high levels of diesel exhaust contaminants during
installation or removal of longwall equipment, the final rule adopts
the proposed requirement that minimum air quantities be maintained in
areas where mechanized equipment is being installed or removed.
Paragraphs (h)(1) through (h)(4) of this section of the final rule,
like the proposal, allow certain types of equipment to be excluded from
the minimum air quantity calculation of paragraph (g). The rationale
behind these exclusions is that the specified equipment is operated or
ventilated in such a way that it does not significantly affect the
exposure of miners to diesel exhaust contaminants. Commenters were
generally in favor of allowing certain equipment to be excluded, such
as equipment with light-duty cycles or equipment that is only used
intermittently. One commenter stated, however, that MSHA should verify
information submitted by the operator to support exclusion of
equipment, and that the final rule should require mine operators to
notify miners or their representatives to allow them to comment on the
operator's request for exclusion of equipment from the air quantity
calculation.
In response to this comment the final rule, unlike the proposal,
requires district manager approval of all exclusions and requires the
exclusions to be specified in the ventilation plan. This will allow
MSHA review of all equipment that will be excluded from the air
quantity calculation, and responds to commenter concerns about MSHA
verification of excluded equipment. Additionally, requiring excluded
equipment to be specified in the ventilation plan will ensure that
miners and their representatives, who are required under existing
regulations to be provided with proposed revisions to an operator's
ventilation plan, are notified of an operator's intention to exclude
certain equipment. This
[[Page 55439]]
responds to commenters who advocated that miners' representatives be
notified of and be given an opportunity to comment on such matters.
Paragraph (h)(1) allows the exclusion of self-propelled equipment
meeting the requirements of Sec. 75.1908(b) of the final rule. The
proposal would have allowed the exclusion of the limited class of
equipment meeting the requirements of proposed Sec. 75.1908, except
diesel-powered air compressors that are regularly used. The
requirements of proposed Sec. 75.1908 included specific objective
criteria limiting equipment horsepower and weight. In response to
commenters and for reasons explained in detail in the preamble to
Sec. 75.1908, equipment categories are defined in the final rule by the
equipment function rather than by weight or horsepower. Equipment that
meets the requirements of Sec. 75.1908(b) is light-duty equipment that
does not, among other things, cut or move rock or coal or move longwall
components. Because the equipment is not operated under heavy load, it
is not expected to produce high levels of exhaust emissions, and may
therefore be excluded if specified in the mine operator's approved
ventilation plan. Although the proposal did not explicitly limit the
exclusion to self-propelled equipment, as does the final rule, the only
portable equipment included in the proposed limited class was
compressors and welders, and compressors were not eligible for
exclusion under the proposal if they were regularly operated. The final
rule takes a different approach and only includes self-propelled light-
duty equipment in the automatic exclusion under paragraph (h)(1),
because some types of non-self-propelled light-duty equipment, such as
compressors and generators, can produce high levels of exhaust
emissions. However, light-duty equipment that is not self-propelled
whose emissions would not significantly affect the exposure of miners
may be excluded from the air quantity calculation if approved by the
district manager under paragraph (h)(4).
Also eligible for exclusion, under paragraphs (h)(2) and (h)(3), is
equipment that discharges its exhaust into an intake air course that is
vented directly into a return air course, or that discharges its
exhaust directly into a return air course. Paragraph (h)(3), which
exempts equipment vented directly into a return air course, has been
adopted without change from the proposal. Paragraph (h)(2), which
exempts equipment that discharges its exhaust into intake air that is
coursed directly to a return air course, has been added to the final
rule to be consistent with other MSHA regulations, which require
certain equipment, such as electrical equipment, to be vented either
directly into a return air course or into an intake air course that is
coursed directly into a return air course. The rationale for both of
these exceptions in the final rule is the same: that the diesel exhaust
of equipment that discharges into a return air course or into an intake
air course that goes directly into a return air course will not, in
most cases, come into contact with miners because most of them will be
working in intake air in the face area where production occurs.
Commenters did not indicate any opposition to the reasoning behind
these exceptions.
Paragraph (h)(4), like the proposal, allows mine operators to
obtain MSHA approval for the exclusion of other equipment from the air
quantity calculation in paragraph (g). Equipment may be excluded under
this paragraph if its duty cycle is such that the emissions would not
significantly affect the exposure of miners. Mine operators who seek to
exclude equipment must identify the equipment in the ventilation plan
that is submitted to MSHA for approval. Equipment that may be eligible
for exclusion under paragraph (h)(4) includes equipment with a very
small engine (less than 10 horsepower) or heavy-duty equipment that is
operated infrequently, for very short periods of time, or when other
diesel equipment normally operated on the section is shut down or not
operating. An example of equipment that could be considered for
exclusion under this paragraph is a supply vehicle that is driven up to
the section, shut down and unloaded, started up and immediately driven
off of the section. Equipment that is operated in a location so that
its exhaust does not pass over miners could also be eligible for this
exclusion. All other equipment, such as nonpermissible heavy-duty
equipment and face equipment which discharges its exhaust into an
intake air course of the working section, must be included in the
minimum air quantity calculation required by paragraph (g).
Paragraph (i) of the final rule, like the proposal, allows the
district manager to approve a lesser air quantity than what would
otherwise be required under paragraph (g) for multiple units of diesel
equipment. The final rule allows such a modification if sampling
results demonstrate that miners exposure to diesel contaminants will
not exceed applicable TLV's at the modified ventilation
quantity.
The proposed rule would have allowed the district manager to
approve lesser air quantities for multiple units of equipment if the
results of a comprehensive personal monitoring program indicated that
contaminant exposure levels were below 75 percent of the applicable
contaminant standards with 95 percent confidence. The proposed rule
also specified the information that mine operators would have been
required to submit to MSHA for consideration in reducing minimum air
quantities, including the actual sampling plan and an evaluation of the
sampling results.
Some commenters were opposed to requiring a 95 percent confidence
level for the sampling used to support a reduction in air quantity,
stating that this requirement was too technical and unrealistic for
practical application. Some commenters strongly opposed allowing
reduction of air quantities under the procedure set forth in the
proposal, stating that miners and their representatives would not be
given sufficient opportunity to participate in the process. One
commenter advocated use of petition for modification procedures under
section 101(c) of the Federal Mine Safety and Health Act when mine
operators seek to revise their ventilation plans, stating that under
these procedures miners and miners' representatives would have the
right to review and comment on the proposed plan modifications.
The final rule takes a more performance-oriented approach to
reduction in minimum air quantities, and requires that samples of
contaminants demonstrate that a lesser air quantity will maintain
contaminant levels within permissible limits. This is consistent with
the streamlined procedures for contaminant sampling in Sec. 70.1900 of
the final rule, and also responds to commenters' recommendations that
this aspect of the rule should be less technical.
The objective of this aspect of the final rule is the same as that
of the proposal: that reduction of minimum air quantities required by
the final rule is permitted if a mine operator can establish that
miners will not be overexposed to gaseous diesel exhaust contaminants
at the lesser ventilating air quantities.
The final rule does not adopt the suggestion of commenters that
reductions in air quantity be granted only under the modification
procedures of section 101(c) of the Mine Act. Since the time of the
submission of these comments, MSHA has issued a final rule governing
underground coal mine ventilation, which includes revisions to the
existing ventilation plan submission and approval process [61 FR 9764]
and addresses several of these commenters' concerns. The revised
ventilation rules
[[Page 55440]]
provide an increased role for the representative of miners in the
ventilation plan approval process. Mine operators are now required to
notify the representative of miners at least 5 days before a
ventilation plan or plan revision is submitted to MSHA for approval,
and make a copy of the proposed plan or plan revision available for
inspection to the miners' representative. The representative of miners
is given the opportunity to submit written comments to MSHA for
consideration during the plan review process. Under this process,
operators seeking reduction in the minimum air quantities required
under paragraph (g) are required to notify miners' representatives, who
then have the opportunity to comment on the reduction. No provisions
have therefore been made to address these comments in the final rule,
because the comments have already been addressed appropriately in the
revised ventilation rule.
Paragraph (j) allows modification of the 50 percent action level
specified in Sec. 70.1900(c) if sampling results demonstrate that
miners will not be exposed to contaminants that exceed permissible
limits at the modified action level. As described in detail in the
preamble discussion for Sec. 70.1900, any change to the action level
must be based on the results of sampling that demonstrate that miners'
personal exposure will not exceed the applicable TLV.
Paragraph (k) provides that, as of 12 months after the publication
date of the final rule, the ventilating air quantity required where
diesel-powered equipment is operated shall meet the requirements of
paragraphs (f) through (j) of this section. Compliance with the
ventilation requirements of the final rule will in some cases require
modifications to the mine's ventilation system. These revisions, along
with other information required to be specified in the mine ventilation
plan under paragraphs (f) through (j) of this section, should be
included in a revised ventilation plan submitted to MSHA for review and
approval.
Section 75.371 Mine Ventilation Plan; Contents
The requirements for diesel-powered equipment that are included by
the final rule in existing Sec. 75.325 identify information that must
be specified in the mine operator's ventilation plan. Existing
Sec. 75.371, which lists the information that must be provided by mine
operators in their mine ventilation plans, is amended by the final rule
to conform to the new requirements in Sec. 75.325.
As was true under the proposal, minimum air quantities for
individual units of diesel-powered equipment are not required to be
included in the ventilation plan, because individual units are required
to be ventilated with at least the engine approval plate air quantity
while they are operating. The final rule does require that the
ventilation plan specify where air quantity will be maintained at the
section loading point for individual units of equipment, as well as any
additional locations required by the district manager where a minimum
air quantity must be maintained for an individual unit of equipment.
The final rule, like the proposal, requires the ventilation plan to
specify ventilation quantities for multiple units of equipment, as well
as to include a description of equipment that is excluded from the
multiple unit calculation of Sec. 75.325(g).
Existing Sec. 75.371(r) is revised by the final rule to include a
cross-reference to Sec. 75.325 (d), (g), and (i). Paragraph (r)
requires the ventilation plan to identify the minimum quantity and the
location of air that will be provided during the installation and
removal of mechanized mining equipment, as well as the ventilation
controls that will be used. The addition of a cross-reference to
Sec. 75.325 clarifies that minimum air quantity requirements for
diesel-powered equipment must be considered when determining
ventilation quantities during mechanized equipment installation and
removal.
New paragraph (kk) has been added to Sec. 75.371 and provides that
the ventilation plan shall include any additional areas designated by
the district manager under Sec. 70.1900(a)(4) of the final rule for CO
and NO2 sampling. As explained in more detail in the preamble to
Sec. 70.1900, the district manager is authorized under the final rule
to require sampling in strategic locations on a mine-by-mine basis, in
order to address situations involving significant concentrations of
diesel exhaust. Paragraph (kk) conforms the content requirements for
ventilation plans to this new provision.
New paragraph (ll) provides that the ventilation plan must specify
the location where the air quantity will be maintained at the section
loading point.
New paragraph (mm) provides that the ventilation plan include any
additional locations required by the district manager, under
Sec. 75.325(f)(5), where a minimum air quantity must be maintained for
an individual unit of diesel-powered equipment.
New paragraph (nn) provides that the ventilation plan must specify
the minimum air quantities that will be provided where multiple units
of diesel-powered equipment are operated. To comply with this
requirement, mine operators should indicate the equipment that is being
used in the normal mining cycle, and the minimum air quantities that
must be provided to ventilate the specified equipment.
New paragraph (oo) provides that the ventilation plan must specify
the diesel-powered equipment excluded from the calculation under
Sec. 75.325(g). MSHA does not intend that this provision require the
itemization or the serial numbers of specific equipment. Instead, the
mine operator should provide a general description that is sufficient
to identify the types of equipment that are excluded from the
calculation.
New paragraph (pp) conforms ventilation plan content requirements
to Secs. 70.1900(c) and 75.325(j), and provides that the ventilation
plan shall identify any action levels that are higher than the 50
percent level specified by Sec. 70.1900(c). As described in greater
detail in the preamble discussion of Sec. 70.1900, mine operators may
obtain a higher action level if they are able to demonstrate that
miners will not be overexposed to contaminants at the higher level. If
a higher action level is approved by the district manager under
Sec. 75.325(j), it must be specified in the mine ventilation plan.
Section 75.1900 Definitions
This section of the final rule contains definitions of terms used
in subpart T of part 75. These definitions are provided to assist the
mining community in understanding and complying with the requirements
of the final rule. As a general matter, terms which are unique to the
final rule are defined, while those terms that are commonly used and
understood in the mining industry have not been included for
definition.
The proposed rule defined two terms: ``fixed underground diesel
fuel storage facility'' and ``mobile underground diesel fuel storage
facility''. The final rule adopts the proposed definition for ``fixed
underground diesel fuel storage facility'', although the term itself
has been slightly modified, with the substitution of the word
``permanent'' for the word ``fixed'' to more accurately reflect the
nature of the facility. A ``permanent underground diesel fuel storage
facility'' is defined as a facility designed and constructed to remain
at one location for the storage and dispensing of diesel fuel, and
which does not move as mining progresses. Such facilities are designed
to remain at
[[Page 55441]]
one location for an extended period of time. Additionally, the final
rule also adopts, with slight modification, the proposed definition for
``mobile underground diesel fuel storage facility'', although that term
has been changed in the final rule to ``temporary underground diesel
fuel storage area'' to be more accurately descriptive. A ``temporary
underground diesel fuel storage area'' is defined as an area of the
mine provided for the short-term storage of diesel fuel in a fuel
transportation unit, which moves as mining progresses.
The final rule also includes additional definitions for the terms
``diesel fuel tank'', ``diesel fuel transportation unit'',
``noncombustible material'', and ``safety can''.
Several commenters believed that the definitions in the proposal
were too narrow in scope and did not accurately reflect the different
fuel storage facilities currently in use in underground coal mines or
the different applications of mobile diesel-powered equipment. These
commenters recommended the definition of two additional categories of
underground diesel fuel storage facilities: ``temporary'' and ``self-
propelled.'' Commenters offered definitions for these two additional
types of facilities, but they have not been adopted in the final rule,
although, as mentioned above, the word ``temporary'' has been
substituted for the word ``mobile'' in describing areas provided for
short-term fuel storage that move as mining progresses. The suggested
definition for ``self-propelled diesel fuel storage facility'' has not
been included because it is similar in function and definition to a
``diesel fuel transportation unit,'' which has been defined in the
final rule.
The definition offered by commenters for ``temporary diesel fuel
storage facility'' reflected commenters' concerns that the proposed
construction requirements for mobile fuel storage facilities were too
extensive, and would make it difficult for the facility to move with
the section and keep pace as mining progressed. Commenters therefore
recommended the creation of a category of fuel storage facility with
more flexibility than the mobile storage facilities under the proposal.
In response to these comments, requirements for temporary fuel
storage are addressed separately from those for permanent facilities in
the final rule, and reflect a more practical approach to temporary fuel
storage, which is explained in detail in the discussion of
Sec. 75.1903, below. A definition for ``temporary fuel storage
facility'' is consequently unnecessary and has therefore not been
adopted in the final rule.
One commenter recommended that several other terms be defined in
the final rule, including ``container,'' ``safety can,'' ``tank,'' and
``fuel transportation unit.'' This commenter pointed out that these
terms are used throughout subpart T, and definition of these terms
would enhance understanding of the requirements of the final rule.
MSHA agrees that definition of certain terms will facilitate
compliance with the requirements of subpart T, and has therefore
included definitions for ``diesel fuel tank,'' ``diesel fuel
transportation unit,'' ``noncombustible material,'' and ``safety can.''
Because the term ``fuel storage container'' is not used in the final
rule, a definition for this term is not included in the final rule.
The term ``diesel fuel tank'' is defined in the final rule as a
closed metal vessel specifically designed for the storage or transport
of diesel fuel. Metal tanks are required based on metal's demonstrated
ability to contain diesel fuel in the event of a fire, documented by
the Bureau of Mines in a 1985 Report of Investigation entitled ``Fire
Tests of Five-Gallon Containers Used for Storage in Underground Coal
Mines'' (RI 8946). This type of construction is also consistent with
the National Fire Protection Association (NFPA) ``Standards for
Portable Shipping Tanks for Flammable and Combustible Liquids'', (NFPA
386).
The term ``diesel fuel transportation unit'' is defined as a self-
propelled or portable, wheeled vehicle used to transport a diesel fuel
tank. This definition includes diesel-powered vehicles such as lube
units, maintenance trucks, tractors, and scoops. This definition also
includes locomotives that pull rail-mounted, portable diesel fuel
transportation units. Under the final rule fuel transportation units
must be wheel-mounted, since skid-mounted units are more likely to be
damaged during loading and unloading in a scoop bucket or while being
dragged through the mine. Required safety features for these units are
contained in Sec. 75.1902 and Secs. 75.1904 through 75.1906 of the
final rule. Additionally, self-propelled fuel transportation units that
are diesel-powered, and diesel-powered equipment used to tow portable
fuel transportation units are considered heavy-duty equipment under
Sec. 75.1908(a). Heavy-duty equipment must be provided with the safety
features specified in Sec. 75.1909, including an automatic fire
suppression system and additional specifications for the equipment's
braking system.
Under the final rule, permanent underground diesel fuel storage
facilities must be constructed of ``noncombustible materials,'' and
stationary tanks in those facilities must be placed on 12-inch supports
constructed of ``noncombustible material.'' ``Noncombustible material''
is defined in the final rule as a material that will continue to serve
its intended function for 1 hour when subjected to a fire test
incorporating an ASTM E119-88 time/temperature heat input, or
equivalent. This test, contained in the publication ``Standard Test
Methods for Fire Tests of Building Construction and Materials'' of the
American Society for Testing and Materials, is used to establish fire
resistance ratings in minutes or hours for a particular building
assembly such as a roof, wall, or beam. This means that a material
maintains its integrity under a fire exposure test used by the building
industry to classify assemblies for their ability to resist fire. This
definition is consistent with the definition of ``noncombustible
material'' in existing Sec. 75.301, which applies to the construction
of ventilation controls in underground coal mines.
One commenter who recommended that ``noncombustible material'' be
defined in the final rule suggested that the definition specify a 2-
hour fire rating. The definition in the final rule specifies a 1-hour
rating, which will provide protection in the event of a fire in
underground fuel storage areas by confining the fire within the area
for a sufficient period of time to allow miners to safely evacuate the
mine. Additionally, the final rule requires automatic fire suppression
systems and audible and visual alarms for permanent underground fuel
storage facilities. For these reasons, adequate protection of miners
against fire is provided, and a 2-hour fire rating has not been adopted
in the final rule.
The term ``safety can'' is defined in the final rule as a metal
container with a nominal capacity of no more than 5 gallons used for
storage, transport, or dispensing of diesel fuel that is listed or
approved by a nationally recognized independent testing laboratory.
Commenters supported the use of approved safety cans to transport small
amounts of diesel fuel. This definition provides assurance that
adequate construction and performance specifications for fire
protection are met. The limitation on the capacity of safety cans to no
more than 5 gallons will control the amount of diesel fuel being
transported and minimize potential fuel
[[Page 55442]]
spillage. Such specifications and limitations are necessary in light of
accident reports of 10 fires in Canadian mines that resulted from
diesel fuel spillage during refueling.
A safety can that meets this definition could be listed by
Underwriters Laboratories or approved by Factory Mutual, Inc. Some
nationally recognized independent testing laboratories have established
specific construction specifications for the type and thickness of
materials; material strength, stability and resistance to leakage; and
standards for fire exposure that ensure that the can will safely vent
if exposed to a heat source such as a fire.
The final rule defines ``safety can'' as a metal container. Thus, a
plastic safety can listed or approved by a nationally recognized
independent testing laboratory would not be acceptable under the final
rule. A metal container is specified because metal is superior to
plastic in containing diesel fuel in the event of a fire. The safety
advantage provided by metal cans has been documented in the 1985 Bureau
of Mines' Report cited earlier. Specific design requirements for safety
cans are addressed in Sec. 75.1904 of the final rule.
Section 75.1901 Diesel Fuel Requirements
This section of the final rule establishes specifications for the
fuel used in diesel-powered equipment in underground coal mines.
Satisfying the requirements of this section will lower diesel engine
gaseous and particulate emissions, and will reduce equipment
maintenance by limiting the amount of sulfur in the fuel. The risk of
fire in underground coal mines is also reduced by the minimum flash
point for the fuel required by the final rule. The safety benefits that
result from this aspect of the final rule are particularly important in
the confined environment of an underground coal mine.
Paragraph (a) of this section requires that diesel fuel used in
underground coal mines contain no greater than 0.05 percent sulfur and
have a flash point of 100 deg. F (38 deg. C) or greater. The final rule
also requires the mine operator to provide an authorized representative
of the Secretary, upon request, with evidence that the diesel fuel
purchased for use in diesel-powered equipment underground meets these
requirements.
The proposed rule would have required ASTM D975 No. 2D diesel fuel,
with a flash point of 125 deg. F or greater, at standard temperature
and pressure. Many commenters objected to the requirement for ASTM D975
No. 2D diesel fuel, stating that the reference to No. 2D fuel was a
manufacturing classification, did not describe a type of diesel fuel
that was commercially available, and would unnecessarily limit the use
of diesel fuel in underground coal mines.
MSHA agrees with commenters that the proposed fuel specifications
do not describe a fuel that is commercially available, and the fuel
specifications contained in the final rule respond to these comments.
The reference to ASTM D975 No. 2D diesel fuel has been eliminated, and
a minimum flash point and maximum sulfur content for diesel fuel have
been specified. The fuel described by the final rule is in widespread
use throughout the United States, and is easily obtained by mine
operators. The fuel specifications in the final rule are based on
Environmental Protection Agency on-highway fuel requirements for
commercially available diesel fuel.
A number of commenters were concerned that the required flash point
of diesel fuel not be set too low, stating that any diesel fuel
specifications must keep the fuel within the class of combustible
liquids, ensuring that hazards associated with diesel fuel are no
greater than those associated with other combustible liquids used
underground. Some of these commenters recommended that the flash point
for diesel fuel be set at 140 deg. F, stating that lower flash points
would increase the risk of vaporization and increased aromatic content,
especially at warmer mine temperatures. These commenters stated that
increased aromatic content has an effect on particulate emissions.
Other commenters stated that the proposed flash point of 125 deg. F
was too high. Some commenters reported that the flash point of diesel
fuel is intentionally lowered when fuel suppliers mix it for a winter
blend, to depress the cloud point of the diesel fuel and reduce the
temperature at which the fuel begins to jell. These commenters believed
that a flash point of 125 deg. F would virtually eliminate their
ability to use diesel-powered equipment in cold temperatures, unless
the rule specifically allowed the use of winter blends of diesel fuel
with flash points below 125 deg. F. These commenters pointed out that
the ASTM 975 specification for diesel fuel is being changed to lower
the minimum flash point of D1 diesel fuel to 100 deg. F (38 deg. C)
when the cloud point is lower than 10 deg. F, and that a reduction of
the flash point in the final rule was appropriate.
Another commenter believed that the diesel fuel autoignition point
does not change in the lower range of flash point for diesel-powered
equipment, concluding that the safety of diesel fuel exposed to hot
surfaces would not change with changing flash points.
No demonstrated hazard exists to justify raising the flash point of
diesel fuel above the proposed flash point of 125 deg. F. However, MSHA
acknowledges commenters' concerns that the proposed flash point may
unintentionally limit the use of diesel fuel during the winter. To
address this issue, the flash point has been lowered in the final rule
to 100 deg. F (38 deg. C) or greater.
Several commenters suggested that the terms ``flash point'' and
``combustible liquid'' be defined, with some commenters offering
recommended language for the definitions. The final rule does not
include definitions for these terms. The term ``flash point'' is
commonly understood in the mining industry to mean the lowest
temperature at which a liquid will give off sufficient vapor to ignite
on application of a flame, and does not need to be defined in this
rule. The suggested definition offered by commenters for the term
``combustible liquid'' specifies a flash point temperature. Because the
final rule sets a minimum flash point temperature for diesel fuel, such
a definition is unnecessary.
The proposal did not set a limit on sulfur content for diesel fuel,
but would have required sampling for sulfur dioxide when diesel fuel
was used that contained more than 0.25 percent sulfur. This approach
was taken because, although the proposal recognized that use of low
sulfur fuel was desirable, it was not readily available nationwide at
the time the proposal was published in October 1989.
Some commenters stated that the sulfur content of diesel fuel
should be limited in all cases to 0.25 percent. Others stated that a
sulfur content requirement should be phased in, ultimately reaching the
Environmental Protection Agency's maximum sulfur level of 0.05 percent.
One commenter stated that a requirement for low sulfur fuel would
provide a health benefit to miners by reducing particulate emissions.
MSHA agrees that the sulfur content of diesel fuel should be kept
at a low level. Sulfur in diesel fuel contributes to diesel particulate
emissions. Additionally, some types of exhaust after-treatment
technology designed to lower hazardous diesel emissions work better
when the sulfur content in the fuel is low. More effective strategies
for after-treatment technology will result in reduced hydrocarbons and
carbon monoxide levels. Low sulfur fuel also
[[Page 55443]]
greatly reduces the sulfate production from the catalytic converters
currently in use in underground coal mines, thereby decreasing exhaust
pollutants. Today, low sulfur fuel is readily available and widely used
by on-road commercial vehicles. For these reasons, the final rule
requires that diesel fuel contain no greater than 0.05 percent sulfur,
which fuel is readily available nationwide.
Under Sec. 70.1900 of the proposal, mine operators would have been
required to provide MSHA with a certified statement if the sulfur
content of the fuel used in their diesel equipment was 0.25 percent or
less. This provision was included with exposure monitoring requirements
because use of high sulfur fuel under the proposed rule would have
triggered weekly area sampling requirements. Specifications for diesel
fuel are now addressed in paragraph (a) of this section of the final
rule, and the operator's obligation to verify the fuel's sulfur content
has also been included in this section.
The final rule requires the mine operator to provide to an
authorized representative of the Secretary, upon request, evidence that
the diesel fuel purchased for use in diesel-powered equipment
underground meets the requirements of paragraph (a). This will not be a
burdensome requirement. MSHA anticipates that the mine operator's
contract with the mine's fuel supplier will document the type of fuel
that is being purchased. The verification required under this paragraph
may also be provided by a copy of a fuel analysis, which can be
performed by a supplier's quality control laboratory or a private
laboratory at minimal or no cost to the operator. MSHA recognizes that
purchase orders and invoices may be kept at a mine's administrative
office rather than at the mine site. Although the final rule does not
specify a location or manner of recordkeeping for the document
evidencing diesel fuel content, the mine operator may choose to keep an
additional copy of the document to be easily accessible to a
representative of the Secretary. A small recordkeeping burden is
estimated for this requirement under the Paperwork Reduction Act of
1995.
Paragraphs (b) and (c) of this section of the final rule address
additives for diesel fuel used in diesel-powered equipment in
underground coal mines. The requirements of these two paragraphs were
not part of the proposal but have been added to the final rule in
response to commenters' concerns over the types of substances that
could be safely added to diesel fuel.
Paragraph (b) prohibits the addition of flammable liquids to diesel
fuel. One commenter expressed concern that the proposed rule would not
prohibit flammable liquids, such as gasoline, from being mixed with
diesel fuel underground to assist in machine starting and operation
during cold weather. Because gasoline is highly flammable, adding it to
diesel fuel could cause the flash point of the fuel to drop below
100 deg. F (38 deg. C) and transform the fuel into a flammable liquid.
Further, use of gasoline as a diesel fuel additive could ruin an
engine's fuel system by reducing the lubricating properties of the
fuel. In response to these concerns, the final rule prohibits the
addition of flammable liquids, such as gasoline, to diesel fuel. This
restriction will promote the safe use of diesel fuel underground.
Kerosene, on the other hand, is commonly used as a cutter stock for
lowering the cloud point in diesel fuel. Because kerosene has a flash
point above 100 deg. F (38 deg. C) it is classified as a combustible
rather than a flammable liquid and therefore may be added to diesel
fuel under the final rule.
Paragraph (c) permits only diesel fuel additives that have been
registered with the Environmental Protection Agency (EPA) under 40 CFR
Part 79 [59 FR 33042] to be used in diesel-powered equipment
underground. Because the proposed rule was silent on whether the use of
diesel fuel additives would be permitted, a number of commenters raised
additives as an issue and advocated that the final rule permit them to
be used. These commenters stated that additives served to depress the
cloud point of diesel fuel during cold weather to prevent jelling of
the fuel. A cloud point depressant works by breaking down larger size
crystals to smaller crystals, thus allowing the fuel to flow more
freely. Several commenters expressed concern about the effect additives
may have on diesel exhaust particulate emissions when mixed with diesel
fuel. Other commenters wanted to be permitted to use additives, such as
barium additives, with diesel fuel used to power equipment underground.
One commenter stated that MSHA should encourage further research on the
use of additives.
The wide variety of diesel fuel additives currently on the market
makes control of the use of these additives difficult. The final rule
addresses this issue by limiting fuel additives used underground to
those registered under specific EPA regulations.
EPA regulations at 40 CFR Part 79 forbid manufacturers from placing
any fuel additive into commerce unless the additive has been registered
with the EPA Administrator. The EPA registration process requires the
submission of extensive test data for specific health effect endpoints,
as well as a general systemic and organ toxicity literature search on
the health and welfare effects of the fuel additive emissions,
including the characteristics of the emissions. Registered fuel
additives are maintained by the EPA on a list that is available to the
public.
The requirements of this paragraph do not place an undue burden on
mine operators, because operators need only verify with their fuel
supplier or distributer that the additive purchased is included on the
EPA registration list.
Section 75.1902 Underground Diesel Fuel Storage--General Requirements
This section of the final rule provides general requirements for
the safe storage of diesel fuel underground. These requirements are
intended to minimize risks associated with fire hazards in the areas
where diesel fuel is stored. This section limits the receptacles that
may be used for diesel fuel storage underground to diesel fuel tanks
and safety cans; allows only one diesel fuel transportation unit in a
temporary fuel storage area; places a 1000-gallon limit on the capacity
of stationary diesel fuel tanks in permanent fuel storage facilities;
and limits the location of permanent fuel storage facilities and
temporary fuel storage areas underground.
A number of commenters were concerned about the additional hazards
that would be created by the storage of a combustible--diesel fuel--in
underground coal mines. Some commenters opposed any type of fuel
storage underground, while others believed that diesel fuel can be
safely stored. Those commenters who opposed the storage of diesel fuel
underground stated that it would present numerous safety hazards,
including an increase in the probability of the fuel becoming involved
in a mine fire and cutting off the avenue of escape for miners. These
commenters recommended that language in existing MSHA regulations at
Sec. 31.9 (c)(2) and (c)(3) be incorporated in the final rule. These
regulations address refueling of diesel locomotives underground and
provide that, whenever possible, locomotive fuel tanks be filled on the
surface; contain specific requirements when locomotives are refueled
underground; and prohibit underground fuel storage.
Commenters opposed to allowing storage of diesel fuel underground
suggested that mine operators could file a petition for modification
under Section 101(c) of the Mine Act if they
[[Page 55444]]
had a compelling need to store diesel fuel underground. These
commenters felt that a case-by-case approach would more effectively
address hazards associated with diesel fuel storage.
Commenters were also concerned with maintenance and upkeep of
diesel fuel areas. These commenters stated that fuel spills and hose
leakage could possibly contribute to fire hazards. Commenters expressed
reservations about storage, transport, and dispensing of diesel fuel
from 5-gallon cans, particularly during refueling, stating that
temporary storage should not be allowed. These commenters wanted
assurance that if diesel fuel storage were allowed underground,
protections such as fireproof enclosures and pumps and other provisions
that address fuel spillage would be provided.
Some commenters suggested that diesel fuel storage should be
allowed only if it is tightly controlled, and that fuel spills must not
be tolerated in areas of the mine that cannot be cleaned. A number of
commenters recommended setting limits on the maximum quantity of fuel
allowed on a production section, ranging from a 24- to a 48-hour
supply. Other commenters supported permitting diesel fuel storage
underground, but raised a number of issues related to fuel storage,
such as appropriate construction requirements for underground
facilities; fire protection; and the logistics of transporting and
dispensing fuel in an underground environment. One commenter cited
years of positive industry experience with safe underground storage and
transport of diesel fuel. He stated that his own experience in safely
operating an underground coal mine, including diesel fuel delivery,
storage, transport and transfer, countered the proposition that
proliferation of diesel fuel storage facilities would occur in an
uncontrolled manner, resulting in unlimited quantities of diesel fuel
being stored in underground mines.
MSHA has carefully reviewed all of the comments in determining how
to address the storage of diesel fuel underground. Both MSHA and
industry experience demonstrate that diesel fuel can be safely stored
underground in limited quantities under controlled conditions. Allowing
limited storage on the section will minimize other safety concerns
cited by commenters, such as fuel leaks and spills. Underground fuel
storage will also eliminate the need for frequent fuel trips, thus
reducing hazards that are inherent in the transportation of diesel
fuel. MSHA does not believe that it is useful or practical to restrict
diesel fuel quantities based on projected use. The final rule instead
sets specific gallon limits on the capacity of underground fuel storage
tanks.
The final rule establishes safety requirements, including design
and performance specifications for storage tanks, transportation
vehicles, and cans for fuel storage; a limitation on the number of fuel
storage units that may be parked on a section; and a limitation on the
capacity of underground fuel storage facilities. MSHA believes that
these requirements will provide a significant measure of additional
protection from the hazards associated with the storage and handling of
diesel fuel, and permit efficient and safe transportation and refueling
of diesel equipment in underground coal mines. Under the final rule,
miners are afforded protections that are equal to or greater than the
protections of existing standards.
Paragraph (a) of this section provides that diesel fuel shall be
stored in: (1) Diesel fuel tanks in permanent underground diesel fuel
storage facilities; (2) diesel fuel tanks on diesel fuel transportation
units in permanent diesel fuel storage facilities or temporary diesel
fuel storage areas; or (3) safety cans. The proposal did not explicitly
limit fuel storage underground to tanks and safety cans, and would have
required that diesel fuel be transported in containers specifically
designed for the transport of diesel fuel.
MSHA recognizes that large quantities of diesel fuel must be used
in some mines. However, to protect against fires, spills, and other
hazards, large quantities can only be stored in permanent facilities
under this final rule.
The final rule permits fuel storage in tanks on fuel transportation
units, but only under certain conditions and in limited quantities
spelled out in other requirements in this section. A number of
commenters recommended that the rule accommodate the need for fuel
supplies to move as the production section moves. Other commenters
expressed concerns that multiple mobile storage tanks might be located
on the section at the same time, exposing miners to hazards,
particularly from fire. The final rule also allows diesel fuel to be
stored in safety cans.
The restrictions contained in paragraph (a) respond to commenters'
concerns that storage of diesel fuel underground would lead to
prolific, uncontrolled storage practices, and strictly limit the
locations and receptacles for diesel fuel storage.
Paragraph (b) of this section limits the capacity of stationary
diesel fuel tanks in permanent underground fuel storage facilities to
1,000 gallons. It is important to note that, while the total capacity
of the fixed tanks is set, there is no limit on the number of
stationary tanks that may be located in the facility. This means that
the 1,000 gallons may be stored, for example, in two 500-gallon tanks
or four 250-gallon tanks.
Like the final rule, the proposal prohibited storage of more than
1,000 gallons of diesel fuel in a permanent facility. Commenters'
opinions of this provision varied, from those who opposed any kind of
fuel storage underground, those who recommended limited storage, to
those who believed that diesel fuel could be safely stored underground.
The final rule balances the concerns raised by those opposed to storage
against the need to store fuel underground to minimize other fuel
handling hazards. The fire protection and construction requirements for
fixed storage tanks and permanent storage facilities in Secs. 75.1903
and 75.1904 of the final rule appropriately and adequately address fire
and other hazards involving diesel fuel, and, when satisfied, will
afford safe storage of the fuel quantities allowed under this section.
Under the final rule, the storage of safety cans and parking of
fuel transportation units in permanent storage areas would also be
permitted. The 1,000-gallon limit applies to the total capacity of
stationary tanks in the fuel storage facility, and the quantity of fuel
in safety cans stored or fuel transportation units parked in the
facility would not be counted as part of the 1,000-gallon limitation
under this paragraph.
The final rule permits storage of diesel fuel on a working section
or in an area of the mine where equipment is being installed or
removed, but places specific restrictions on such storage in paragraphs
(c)(1) through (c)(4) of this section.
The proposal did not separately address storage of diesel fuel on a
working section. MSHA received many comments both opposing and
supporting section fuel storage. Those opposed stated that storage on
the section would present fuel leakage and spillage hazards, creating
fire and escape hazards for miners. Those supporting fuel storage on
the section stated that, because the production section advances
rapidly, the final rule must permit diesel fuel storage on the section.
These commenters further stated that properly designed fuel
transportation units should be allowed on mining sections, as long as
they are parked within reasonable proximity to
[[Page 55445]]
the work area and comply with specific safety requirements.
MSHA agrees with commenters who supported allowing mobile fuel
storage on the section, which can move as mining progresses, but also
agrees with commenters who believe that such storage must be carefully
controlled. In response to these concerns, paragraph (c)(1) permits
only one temporary diesel fuel storage area for each working section or
in areas of the mine where equipment is being installed or removed.
Paragraph (c)(2)(i)-(iii) requires that the temporary fuel storage area
be located within 500 feet of the loading point; within 500 feet of the
projected location of the future loading point where equipment is being
installed; or within 500 feet of the location of the last loading point
where equipment is being removed. This requirement will ensure that the
fuel storage area will be located close enough to miners to allow any
hazards that may develop to be quickly addressed. This provision is a
logical outgrowth of the rulemaking because it addresses commenters'
concerns that fuel storage be allowed in close proximity to the mining
section, while at the same time recognizing that safety concerns
dictate limitations on where fuel may be stored.
Consistent with the final rule's approach of allowing limited
storage on the section, paragraph (c)(3) prohibits more than one diesel
fuel transportation unit at a time to be parked in a temporary diesel
fuel storage area. This requirement is consistent with sound fire
protection engineering principles for the storage and handling of
diesel fuel, and is supported by experiences in the field and
applicable NFPA standards. It should be noted, however, that a
``parked'' diesel fuel transportation unit under this paragraph would
not include a unit that is in the process of refueling equipment or
that is itself being refueled. This means, for example, that a
temporary fuel storage area could contain more than one diesel fuel
transportation unit at one time, so long as only one unit is parked.
Any other units in the area must be in use and attended.
The proposal would have allowed fuel to be stored in free-standing
tanks in mobile diesel fuel storage facilities. The final rule allows
fuel to be stored in temporary fuel storage areas, but only in tanks on
diesel fuel transportation units. These units are specially designed to
provide both mobility and protection for the fuel tanks. Protection is
provided by requiring the tank to be permanently affixed to the
transportation unit. The construction and design requirements for fuel
tanks are contained in Sec. 75.1904 of the final rule.
Paragraph (d) of this section of the final rule imposes limitations
on the location of permanent fuel storage facilities and temporary fuel
storage areas, and has been revised from the proposal for clarity. This
aspect of the final rule requires diesel fuel to be kept out of areas
where the potential for fire is greatest. The final rule prohibits
permanent storage facilities and temporary storage areas from being
located within 100 feet of shafts, slopes, shops, or explosives
magazines, or within 25 feet of trolley wires or power cables, or
electric equipment not necessary for the operation of the storage
facilities. The fuel storage facilities or areas must also be in a
location protected from damage by other mobile equipment.
Some commenters stated that the proposed requirement that diesel
fuel storage facilities be located at least 100 feet away from shafts,
slopes, or shops was not adequate in light of the amount of diesel fuel
involved and the amount of spillage that could occur. Another commenter
stated that requiring shops to be located at least 100 feet away from
fuel storage facilities was inconsistent with proposed Sec. 75.1903(c),
which would have prohibited welding and cutting within 50 feet of
storage facilities. The commenter also noted that in some cases it may
be best to locate the fuel storage facility within 100 feet of the shop
near a return, because this would provide the best direct ventilation
to the return for both the shop and storage facility, but that the
proposed 100-foot requirement could prevent this. The final rule, like
the proposal, adopts separation distances that are consistent with the
National Fire Protection Association 123 Standard for Fire Prevention
and Control in Bituminous Coal Mines. NFPA 123 requires fixed
combustible liquid storage areas to be located a minimum of 100 feet
from explosive magazines, electrical substations, shaft stations, and
shops. MSHA disagrees with commenters who considered a 100-foot
separation distance insufficient in light of the amount of diesel fuel
that could be stored. The design, construction, and fire suppression
system requirements in the final rule that apply to permanent fuel
storage facilities provide adequate protection to miners with a 100-
foot separation distance.
MSHA also disagrees with the commenter who believed that requiring
shops to be located at least 100 feet away from fuel storage
facilities, where cutting and welding are likely to occur, was
inconsistent with a prohibition against welding and cutting within 50
feet of storage facilities. The high volume of vehicle traffic in and
out of the area of the shop warrants a greater separation distance than
for cutting and welding alone.
Finally, the final rule does not adopt the recommendation of the
commenter who advocated allowing a permanent fuel storage facility
closer to a shop than 100 feet, to allow better ventilation of both the
shop and the storage facility. The fire protection afforded by the 100-
foot separation distance outweighs any advantage in ventilation that
would result from allowing a lesser distance.
Paragraph (d)(3) provides that permanent fuel storage facilities
and temporary fuel storage areas must be in a location that is
protected from damage from other mobile equipment. Under the proposal,
fuel storage facilities would have been required to be at least 25 feet
away from haulageways, which are entries where miners and materials are
normally transported. The rationale for this requirement was that areas
where diesel fuel is stored should be out of the line of mine traffic,
where tanks would be exposed to damage from collision with other mine
vehicles. Instead of adopting the proposed requirement, the final rule
takes a performance-oriented approach by providing that storage
facilities and areas be located where they are protected from damage.
This responds to a commenter who indicated the importance of keeping
fuel storage facilities out of the line of traffic.
Paragraph (e) prohibits permanent fuel storage facilities from
being located in the primary escapeway, which provides miners with a
route of escape from the mine in the event of an emergency. This
restriction was not included in the proposal, but has been added to
this section of the final rule in response to commenters' concerns
relative to diesel fuel storage facilities' impeding miners' ability to
escape in the event of a mine fire, explosion, or other emergency. This
prohibition recognizes that the primary escapeway should be kept clear
of obstructions and potential hazards, to ensure that miners are able
to safely evacuate the mine in the event of an emergency.
Section 75.1903 Diesel Fuel Storage Facilities And Areas; Construction
And Safety Precautions
This section of the final rule establishes construction and design
requirements for permanent diesel fuel storage facilities and temporary
diesel fuel storage areas. These requirements are intended to minimize
fire hazards associated with storage of diesel fuel
[[Page 55446]]
underground, and provide safety protections for miners during the
storage, transportation, and dispensing of diesel fuel.
The proposal did not distinguish between construction and design
requirements for those diesel fuel storage facilities that are fixed
and remain in one location indefinitely, and those that move as the
production section advances. A number of commenters stated that the
proposed requirements were suitable for permanent facilities but were
unnecessary and impractical for facilities that would be temporary.
Some commenters were concerned that some mine operators would not be
able to complete construction of the temporary facility before the
facility would have to be moved to keep pace with the advancing
section. In support of this position, commenters stated that compliance
with the proposed requirements would be impractical and would force
mine operators to transport fuel to the section to refuel equipment on
a shift basis, creating increased hazards due to transportation.
Another commenter voiced similar concerns, noting that the rapid
advance of mining in modern underground coal mines makes it more
practical for fuel stations to be advanced with mining activity, and
that properly designed transportation units should be allowed on mining
sections as long as they are parked in accordance with specific
safeguards in reasonable proximity to the working area. The commenter
stated that a specific parking requirement with proper safeguards would
be much safer than the requirements in MSHA's proposal. Another
commenter stated that the Diesel Advisory Committee made general
recommendations for permanent and temporary storage facilities that
were not intended to eliminate fuel trailers and their use. On the
other hand, several commenters believed that the fact that the proposal
would not have required mobile storage facilities to have a drain
system and sump would provide no incentive for operators to construct
fixed facilities, and that the construction of an unlimited number of
mobile facilities would result.
In response to the comments, the final rule reflects a clear
distinction between construction and design requirements for permanent
underground diesel fuel storage facilities and temporary underground
diesel fuel storage areas. MSHA recognizes that temporary diesel fuel
storage areas move frequently as mining advances, and that construction
specifications must take this fact into account. Requirements for
permanent storage facilities have therefore been addressed separately
from those for temporary facilities in the final rule. The final rule
provides a more practical approach for the construction and design of
areas designated for temporary fuel storage, and eliminates several
proposed construction requirements that are unnecessary from a fire
protection engineering standpoint. Specifically, the final rule does
not adopt the proposed requirements that temporary fuel storage areas
be constructed of noncombustible material, be provided with a self-
closing door, and be provided with a fire suppression system. Because
construction of temporary storage areas with these features would make
it extremely difficult for these facilities to be built as fast as
mining progressed, transportation of fuel between permanent storage
facilities and the section would increase significantly. The risk of an
accident involving a fuel transportation unit would also increase, and
with it the risk of fuel spillage and the risk of fire. The final rule
therefore reduces the construction requirements for temporary fuel
storage areas, to provide better control of the fire hazards inherent
in fuel transportation and storage.
Paragraphs (a)(1) through (a)(7) of this section establish
construction and design requirements for permanent underground diesel
fuel storage facilities. Consistent with basic fire protection
engineering principles, the final rule requires permanent storage
facilities to be constructed of noncombustible materials; provided with
self-closing doors or a means for automatic enclosure, and with a means
for entry and exit after closure; ventilated with intake air; equipped
with an automatic fire suppression system; and provided with a means to
contain diesel fuel and with a concrete floor or equivalent to prevent
spills from saturating the mine floor. These requirements are intended
to reduce the fire hazards inherently present in areas where diesel
fuel is stored and increase protection in the event of a fire.
The proposal contained requirements similar to those in the final
rule, but the final rule has been modified in response to commenters.
Some commenters were generally opposed to the proposed requirements,
stating that diesel fuel systems currently in use do not pose the
degree of hazard that would warrant such extensive requirements. One
commenter stated that the requirements of the proposal suggested that
the hazards of diesel fuel storage exceed the hazards of the storage of
explosives underground by several-fold. Other commenters stated that
the proposed requirements for construction of storage facilities with
noncombustible materials and with a means for automatic enclosure were
too vague and not stringent enough. These commenters recommended that
MSHA require at a minimum that diesel fuel be stored in an enclosure
with at least a 2-hour fire-resistance rating.
Paragraph (a)(1) provides that permanent underground fuel storage
facilities shall be constructed of noncombustible materials, including
floors, roofs, roof supports, doors, and door frames. Exposed coal
within the fuel storage areas is required to be covered with
noncombustible material. If they are used, bulkheads are required to be
built of or covered with noncombustible material.
The proposal would have required that the storage facility be
constructed of noncombustible material, a term that was not
specifically defined. As discussed above, the term ``noncombustible
materials'' is defined in Sec. 75.1900 of the final rule as materials
meeting the equivalent of a one-hour fire resistance rating test.
Paragraph (a)(1) also incorporates NFPA 123 requirements. These
requirements clarify which components of the facility must be
noncombustible, including floors, roofs, roof supports and door frames,
and specify that exposed coal must be covered with noncombustible
material and bulkheads either built of or covered with noncombustible
materials.
MSHA's Approval and Certification Center has established guidelines
to determine the suitability of trowelable or sprayable coatings for
protecting coal surfaces against fire, which meet the requirements of
paragraph (a)(1). In addition, textile-type thermal barriers may also
be used to provide isolation of the combustible surfaces within the
storage facility. Materials meeting the ``Performance Criteria for
Materials used for Welding and Cutting Curtains and/or Thermal Barriers
in Underground Coal Mines'' (Luzik, MSHA Report No. 01-098-92) may also
be used. MSHA has also established guidelines for noncombustible doors.
Additionally, MSHA has tested certain designs of high-temperature
silica fabric curtains and published the results in Coal Magazine, June
1993, pp. 102-104, ``MSHA Develops New Fire Resistant Check Curtains''.
For purposes of the final rule, MSHA will accept as doors the curtain
constructions described in this article. Facilities constructed to meet
these requirements will afford protection to miners working in the
production areas inby in the event of a fire and should provide ample
time for miners to exit.
[[Page 55447]]
Paragraph (a)(2) of the final rule requires that permanent fuel
storage facilities be provided with either self-closing doors or a
means for automatic enclosure. This paragraph provides mine operators
with flexibility in the method used to comply with the final rule. The
proposal would have required that the facility be provided with a means
for automatic enclosure, which suggests that the door must be closed by
powered means, such as electrically or pneumatically. The proposal did
not specifically include non-powered self-closing doors as an
alternative, although they were not intended to be excluded. Self-
closing doors serve the same function in containing a fire as
automatic-closing doors, and the final rule clarifies that they are
permitted.
Paragraph (a)(3) requires that permanent fuel storage facilities be
provided with a means for personnel to enter and exit the facility
after closure. This provision has been added to the final rule to
ensure that miners who are inside the fuel storage facility when the
automatic enclosure activates will be able to exit from the facility.
This requirement is also intended to allow miners to gain access to the
facility to suppress an incipient fire that may develop. This paragraph
also requires a means for exit and entrance when self-closing doors are
used. Self-closing doors that are specifically designed to be manually
opened would be in compliance with this paragraph. This aspect of the
final rule is necessary to prevent miners from being trapped in the
facility, and is a logical outgrowth of the rulemaking.
Paragraph (a)(4) of this section of the final rule requires that
permanent fuel storage facilities be ventilated with intake air that is
coursed into a return air course or to the surface and that is not used
to ventilate working places, using ventilation controls meeting the
requirements of existing Sec. 75.333(e). The proposal would have
required that both fixed and mobile fuel storage facilities be
ventilated directly into a return air course using noncombustible
materials for ventilation controls. Some commenters stated they were
already venting fuel storage areas in their mines directly to the
return.
The final rule adopts the proposed requirement only for permanent
fuel storage facilities, with some modification. The final rule
requires that the facility be ventilated with intake air coursed to a
return air course or to the surface that is not used to ventilate
working places. This language, which is consistent both with existing
requirements at Sec. 75.340 for the ventilation of underground
electrical installations and with the current definition of ``return
air'' in existing Sec. 75.301, is intended to eliminate the confusion
caused by the phrase ``directly to a return air course''. The final
rule clarifies that the intake air ventilating the fuel storage
facility may not be used to also ventilate active working places. Thus,
the air may be coursed into other entries before being coursed into a
return, so long as the air is not used to ventilate a working place.
Temporary underground diesel fuel storage areas are not required to
be vented directly to the return in the final rule, in response to
commenters who advocated more flexibility and less restrictive
requirements for temporary fuel storage that moves as mining
progresses.
If the permanent facility is equipped with self-closing doors that
would normally be closed, an opening will have to be provided in the
doors to allow intake air to flow through the facility. This opening
will prevent the build-up of diesel fuel vapors in the facility and
prevent smoke generated during the incipient stages of a fire from
entering the intake air courses. The opening is not intended to prevent
smoke and other products of combustion from backing up into the intake
airway if the fire is not extinguished in its incipient stages. For
automatic closing doors, which would normally be open, a vent in the
doors may not be needed since enclosure is required to seal the
facility to cut off oxygen to the fire after the doors have closed.
The requirements of paragraph (a)(4) are also intended to ensure
that, if an enclosure has self-closing doors that are normally closed,
precautions are taken to adequately vent diesel exhaust emissions from
the facility. Such precautions could include the use of a regulator in
the door to bring air into the facility that would then be vented to
the return. In the case of a diesel fuel transportation unit that must
have its engine running to dispense fuel, the unit's exhaust could be
vented either directly to the return, if it incorporates a power
package approved under subpart F of part 7, or into intake air which is
coursed directly to a return air course. A fuel transportation unit
that is equipped with a subpart F-approved power package will have fire
and explosion prevention features that would permit the engine to
exhaust directly into the potentially methane-rich atmosphere of the
return. When the unit is exhausted into intake air, the fire and
explosion prevention features of a subpart F power package are not
required. However, the emissions from the engine must be vented
directly to return air to prevent unnecessary exposure of miners to
diesel exhaust.
Paragraph (a)(5) adopts the requirements of the proposal and
provides that permanent fuel storage facilities must be equipped with
an automatic fire suppression system that meets the requirements of
Sec. 75.1912 of the final rule. This paragraph also includes an
additional requirement, not included in the proposal, that actuation of
the automatic fire suppression system shall initiate the means for
automatic enclosure. One commenter stated that the proposed requirement
for automatic enclosure was not sufficiently stringent, that these
storage facilities should be designed with fire containment capability,
and that automatic enclosure should be triggered by actuation of the
automatic fire suppression system. MSHA agrees, and the final rule
enhances the capabilities of the automatic fire suppression system by
requiring that initiation of the system will activate closure of the
doors to the facility if self-closing doors are not used. Operation of
the system in an environment with minimal air movement, which would
exist when the doors are closed, will improve the effectiveness of fire
suppressant agents in extinguishing a fire.
Paragraph (a)(6) requires that permanent fuel storage facilities be
provided with a means of containment capable of holding 150 percent of
the maximum capacity of the fuel storage system. This provision is
intended to address hazards associated with diesel fuel spillage and
leakage--both slip and fall and fire hazards. The proposal would have
required that permanent facilities be equipped with a drain system and
a sump capable of holding 150 percent of the maximum capacity of the
fuel storage system. Instead of requiring a drain system and sump, the
final rule requires a ``means of containment''. This change
acknowledges that a suitable drain system is generally considered
overly difficult to design and install, and will also allow more
flexibility in design of fuel containment systems. Additionally,
spilled diesel fuel is best left confined in the facility where the
fire suppression system is located. One commenter offered a case that
illustrates this principle where the fuel escaped into the mine during
a fuel spill because the drain valve at the bottom of the remote sump
that serviced the storage area was left partially open.
It is important to note that, in cases where fuel is piped from the
surface to an underground fuel storage facility, the containment
capacity must account for
[[Page 55448]]
the total fuel capacity. This means that the capacity of the
containment must equal at least 150 percent of the surface tank's
capacity, plus 150 percent of the underground tank's capacity, plus 150
percent of the volume of the piping system connecting the surface tank
to the underground tank. In cases where there is no underground tank,
the maximum capacity includes the surface storage tank and the piping
system from the surface. Where a stationary tank is located in a
permanent facility and is not connected to a surface tank, the means of
containment must account for 150 percent of the capacity of the largest
stationary tank. If the underground fuel storage facility is not
equipped with a stationary tank but is used for the storage of only
diesel fuel transportation units, the single largest transportation
unit tank would be counted in the maximum capacity for purposes of this
paragraph. However, diesel fuel transportation units that may be parked
in permanent fuel storage facility where a piping system from the
surface terminates or where a larger stationary tank is housed would
not be considered part of the ``fuel storage system'', and the capacity
of the transportation unit tank would not be included. The rationale
behind this is that only one component in a fuel storage facility would
be expected to fail at one time, such as a burst piping system or a
leak in a stationary tank or in a transportation unit tank.
In support of the requirement of this paragraph, one commenter
noted that a fuel spill occurred when valves in the piping system from
the surface storage tank failed, allowing the static head pressure to
be imparted on the dispensing hose which caused it to rupture and fuel
to escape.
Commenters stated that it is important that the storage location be
designed to contain fuel spills and tank ruptures to stop the spread of
fuel. The final rule's containment capacity requirement of 150 percent
of the capacity of the fuel system will provide a prudent safety factor
in view of the potential fire hazard created by the release of large
amounts of diesel fuel into an underground mine.
Paragraph (a)(7) has been added to the final rule and requires that
permanent fuel storage facilities be provided with a competent concrete
floor or equivalent to prevent fuel spills from saturating the mine
floor. This provision is intended to ensure that spilled diesel fuel
can be easily cleaned up and will not accumulate, creating a fire
hazard. This requirement is added in the final rule in response to
commenters who suggested that the floor of the storage facility should
be noncombustible and impermeable to oil and diesel fuel. These
commenters argued persuasively that a requirement for a concrete floor
would preserve the integrity of a noncombustible facility.
Under the requirements of this paragraph a permanent fuel storage
facility must be provided with a competent floor made of concrete or an
equivalent material. The term ``competent'' is used to make clear that
a cracked concrete floor or a porous mine floor would not satisfy this
requirement. A brattice-type lining or rubber membrane would not be
considered equivalent because it could easily be torn during refueling
of vehicles, and diesel fuel could leak through and accumulate
underneath. This provision has been added to the final rule in direct
response to commenters, many of whom testified at the Agency's public
hearings on the proposal. MSHA believes that this provision constitutes
a logical outgrowth of the proposal because of commenters' stated
concerns in ensuring that spilled fuel will not saturate the mine floor
and create a fire hazard.
The requirements of paragraph (b) of this section of the final rule
apply to both permanent underground fuel storage facilities and
temporary underground fuel storage areas. This paragraph requires that
these storage facilities or areas be: equipped with a 240 pounds of
rock dust and at least two fire extinguishers, or, in the alternative,
with at least three fire extinguishers; be conspicuously marked; and be
maintained to prevent the accumulation of water. These basic
requirements address potential fire hazards in these facilities and
ensure that mine personnel are aware of the presence and location of
such facilities.
Paragraph (b)(1) requires that permanent fuel storage facilities
and temporary fuel storage areas be equipped with at least 240 pounds
of rock dust and provided with two portable multipurpose dry chemical
type (ABC) fire extinguishers that are listed or approved by a
nationally recognized independent testing laboratory and have a
10A:60B:C or higher rating. Both extinguishers must be easily
accessible to personnel, and at least one must be located outside of
the facility or area, upwind of the facility in intake air. Paragraph
(b)(2) provides, as an alternative to the requirement of paragraph
(b)(1), that three fire extinguishers may be provided.
The proposal would have required fixed and mobile fuel storage
facilities to be equipped with at least two 20-pound multipurpose dry
chemical type fire extinguishers, and would not have required that rock
dust be provided. One commenter recommended that foam generating
machines or fire extinguishers of 150 pounds or more be required. The
final rule does not adopt the suggestion of this commenter, because
MSHA considers it too hazardous to fight a diesel fire underground that
cannot be extinguished in its incipient stages. The fire extinguishers
and fire suppression equipment required by this section are intended to
be used to extinguish small fires, such as could occur on equipment in
the facility.
The final rule redefines the type of dry chemical extinguishers
that are required, based on specifications recommended by the National
Fire Protection Association for the particular hazard involved. The
rating of the fire extinguishers has been adopted from NFPA 123 and is
in accordance with NFPA 10-Standard for Portable Fire Extinguishers.
Also, extinguishers must be listed or approved by a nationally
recognized independent testing laboratory, which provides assurance
that the extinguishers will perform effectively in the event of a fire
emergency. The final rule requires that the fire extinguishers be
located so that miners will have quick access to them in the event of a
fire. To allow flexibility in complying with the requirements of this
paragraph, the final rule addresses the location of only one fire
extinguisher. The location of the other extinguisher should be
determined based on mine conditions and the particular usage of the
facility. The final rule specifies that the fire extinguisher be
located upwind of the facility, which has been added to ensure that if
a fire occurs miners will be able to reach the fire extinguisher
without being exposed to the heat or smoke of the fire.
The final rule adds a requirement for 240 pounds of rock dust to be
kept in the storage facility in response to comments concerning the
effectiveness of rock dust in fighting diesel fuel fires and the
ability of rock dust to contain spills. The requirement for 240 pounds
of rock dust is consistent with Sec. 75.1100-2(f), which requires 240
pounds of rock dust to be provided at permanent underground oil storage
stations, and is included in the final rule as an added measure of fire
protection in response to the concerns of commenters. However,
paragraph (b)(2) allows an additional fire extinguisher to be
substituted for the rock dust required under paragraph (b)(1), which is
consistent with provisions in existing petitions for
[[Page 55449]]
modification for fire protection at electrical installations. The
requirements of the final rule strike a balance between those
commenters concerned about the need for additional fire protection
provided by rock dust in locations where diesel fuel is stored, and
those who were concerned that the storage of rock dust in those
locations was inadvisable in mines that tended to be wet.
Paragraph (b)(3) adopts the requirement of the proposal that
permanent diesel fuel storage facilities and temporary fuel storage
areas be identified with conspicuous markings designating diesel fuel
storage. The proposal would have required the facilities to be
designated as ``combustible liquid storage,'' but MSHA has concluded
that precise identification as areas of diesel fuel storage is more
appropriate, and will ensure that mine personnel are aware of the
locations where diesel fuel is stored underground.
Paragraph (b)(4) requires that fuel storage facilities or areas be
maintained to prevent the accumulation of water. The proposal would
have required that fixed and mobile underground storage facilities be
located in an area as dry as practicable, a concept which several
commenters considered to be vague and potentially difficult to comply
with. This requirement has therefore been revised to require that
permanent underground diesel fuel storage facilities and temporary fuel
storage areas be maintained to prevent the accumulation of water. This
provision recognizes that tanks or other components of the storage
facility may corrode as a result of exposure to water. Additionally,
accumulated water can increase the fire hazard present by a fuel spill,
because diesel fuel will float on top of water and may be spread more
easily throughout the storage facility. The requirement of this
paragraph addresses these hazards.
Paragraph (c) adopts the proposed prohibition on welding or
cutting, except as provided in paragraph (d) of this section, from
being performed within 50 feet of a diesel fuel storage facility or
area. This requirement is intended to minimize fire hazards and is
consistent with National Fire Protection Association requirements (NFPA
123). No comments were received on this aspect of the proposal.
Paragraphs (d)(1) and (d)(2) adopt the requirements of the proposal
and set forth specific precautions to be followed when welding,
cutting, or soldering pipelines, tanks, or other containers that might
have contained diesel fuel. MSHA received only a few comments on this
aspect of the proposal, which is consistent with NFPA requirements. A
review of MSHA's accident data reveals that a fatal accident occurred
when the victim was welding a diesel fuel storage tank. The victim had
drained the tank, which had been filled with water, and attempted to
repair a small leak which remained in the tank. Vapors from the
residual fuel were ignited by the heat of welding, and the tank
exploded. The requirements of this paragraph are intended to address
such hazards, and recognize that welding can be performed safely
underground as long as appropriate safeguards are followed.
Additionally, the large size of certain vessels used for the storage of
diesel fuel underground would make it impractical to restrict welding
of such containers to the surface. The precautions in paragraph (d)(1)
include thoroughly purging and cleaning or inerting the pipelines,
containers, or tanks before welding or cutting, with a vent or opening
provided in the container or tank to release pressure before heat is
provided. The final rule also prohibits diesel fuel from entering
pipelines, tanks, or other containers that have been welded, soldered,
brazed, or cut until the metal has cooled to ambient temperature. A
slight change has been made in the language of this requirement to
conform the references to the diesel fuel containers that are the
subject of these requirements. The phrase ``pipelines, tanks, or other
containers'' is used throughout. Additionally, the reference in
proposed paragraph (d)(1) to containers or tanks that ``have contained
combustible or flammable materials'' has been changed in the final rule
to pipelines, tanks or other containers ``that have contained diesel
fuel,'' to eliminate the inconsistency that existed between this
provision and other language in this paragraph and to clarify the scope
of these requirements.
One commenter recommended that a cleanup program be required for
underground fuel storage facilities and areas. This recommendation has
not been adopted in the final rule, because existing Sec. 75.400-2
already requires mine operators to establish and maintain programs for
regular cleanup of accumulations of coal and other combustibles. MSHA
will require that underground diesel fuel storage facilities and areas
be covered by the cleanup program under Sec. 75.400-2, which will
ensure that these locations are kept clear of any combustible
materials.
Section 75.1904 Underground Diesel Fuel Tanks And Safety Cans
This section includes requirements for the design of diesel fuel
tanks and safety cans and for emergency venting devices for diesel fuel
tanks for venting vapors to protect against the buildup of pressure in
the tank, which could lead to its rupture if the tank is exposed to
fire. The requirements of this section are responsive to comments and
are consistent with NFPA, Underwriters Laboratories, and American
Petroleum Institute standards for storage tanks for combustible
liquids. A number of commenters suggested restructuring and
reorganizing the proposed design requirements for diesel fuel tanks,
and the final rule is revised in response to these comments.
Paragraph (a) of this section of the final rule contains
construction and location requirements for underground diesel fuel
tanks in permanent underground fuel storage facilities and temporary
underground fuel storage areas. These requirements are intended to
guard against leakage of diesel fuel and to minimize fire hazards.
Paragraph (a)(1) requires that underground diesel fuel tanks have
steel walls of a minimum \3/16\-inch thickness or walls made of other
metal of a thickness that provides equivalent strength. This
specification has been added to the final rule to ensure that diesel
fuel storage tanks are properly designed for their intended purpose,
and in response to commenters who were concerned that diesel fuel tanks
be durably constructed. MSHA explored alternatives for an objective
measurement of durable construction. The requirement of this paragraph
is consistent with prevailing industry standards, and is intended to
serve as a minimum design standard for substantially constructed tanks.
This requirement is derived from Department of Transportation (DOT)
Spec. 51 Section 178-245-2(b), and is consistent with DOT requirements
for over-the-road vehicles that transport diesel fuel. This
specification is also recognized by the National Fire Protection
Association in many of its fire protection standards as a design
guideline for tanks used for storage of combustible liquids.
Manufacturers of fuel transportation units currently produce diesel
fuel storage tanks with \3/16\-inch thick steel walls, and this
specification will allow mine operators to buy diesel fuel tanks off-
the-shelf.
Paragraph (a)(2) requires diesel fuel tanks to be protected from
corrosion. The proposal would have required these tanks to be
constructed of ``noncorrosive
[[Page 55450]]
material.'' The language of the final rule will allow mine operators
the option of either using a tank that has been constructed of
noncorrosive material, such as galvanized or stainless steel, or of
protecting a tank from corrosion that has been constructed of an
oxidizing material, such as common steel. Protection from corrosion can
be achieved by applying a protective coating.
Paragraph (a)(3) requires diesel fuel tanks to be of seamless
construction or fabricated with liquid tight welded seams. MSHA has
added this requirement to the final rule in response to comments
raising concerns about the durability of fuel tanks in use underground,
to provide an objective measurement of substantial construction. Bolted
and crimped joints are not allowed under the final rule because they
are prone to leakage. The requirement of this paragraph is consistent
with DOT Spec. 51 Section 178-245-2(b), and is intended to ensure that
diesel fuel tanks are well constructed and designed not to leak.
Paragraph (a)(4) requires that diesel fuel tanks not leak, and has
been added in the final rule in response to commenters' concerns that
tanks not contribute to a fire. Under the final rule, all attachments
to the tank, such as vents, caps, hoses, pumps, valves, and nozzles,
must also be free from leaks. Many commenters were concerned with
leakage hazards presented by the storage of diesel fuel underground.
These commenters were particularly concerned about leakage in temporary
diesel fuel storage areas. MSHA believes that the requirement of this
paragraph, in conjunction with the other provisions in this final rule,
will greatly minimize hazards associated with storage of diesel fuel
underground.
Paragraph (a)(5) requires stationary tanks in permanent underground
diesel fuel storage facilities to be placed on noncombustible supports
so that tanks are at least 12 inches above the floor. Under the
proposal such tanks would have been required to be supported by
concrete, masonry, protected steel, or equivalent supports. Steel
supports, except for steel saddles less than 12 inches from the floor,
would have been required to be protected by materials having a fire
resistance rating of not less than two hours. The proposal did not
specify the minimum distance the tank must be from the floor.
Commenters stated that positioning tanks at least 12 inches off the
floor would allow for proper cleaning, rock dusting and quick detection
of leaks. MSHA agrees with these comments and has revised the final
rule accordingly. Additionally, the final rule provides that the tank
supports must be made of noncombustible material, which is defined in
Sec. 75.1900 of the final rule, making unnecessary the reference in the
proposal to ``concrete, masonry, protected steel, or equivalent
supports''. The reference has therefore not been adopted in the final
rule.
Paragraph (b)(1) requires diesel fuel tanks to be provided with
devices for emergency venting that are designed to open at a pressure
that does not exceed 2.5 pounds per square inch. Under this
requirement, the venting devices must also meet minimum size
requirements based on the capacity of the tank. The rule provides
minimum vent device specifications for two ranges of tank sizes: tanks
with a capacity of 500 gallons or less and tanks with a capacity of
more than 500 gallons. The requirements of this section are
incorporated in NFPA standards for portable tanks for transporting and
storage of combustible liquids, as well as in American Petroleum
Institute design standards. These vents are designed to activate at a
pressure which is below the expected yield point of the tank and to
provide the necessary volumetric flow rate to maintain safe internal
pressure if the tank shell were to heat up as a fire develops. Opening
of the device will allow the vapors to be safely vented and will
prevent the tank from rupturing under this condition. Some commercially
available emergency vents have been listed or approved by nationally
recognized independent testing laboratories and can be expected to
provide adequate pressure relief in a fire situation. The vent sizes
required in the final rule were determined by design calculations
outlined in National Fire Protection Association, Underwriters
Laboratories, and American Petroleum Institute standards for a range of
tank sizes typical for underground diesel fuel storage. These
calculations take into account the probable maximum rate of heat
transfer per unit area; the size of the tank and the percentage of the
area likely to be exposed; the time required to bring the tank contents
to a boil; the time required to heat unwet portions of the tank shell
or roof to a temperature where the metal will lose strength; and the
effect of drainage, insulation and the application of water in reducing
the fire exposure and heat transfer. MSHA believes that specifying the
minimum size of vent for two ranges of tank sizes is preferable to a
requirement that would require the operator to design vents for a given
size. The types of emergency vents required under this paragraph are
commercially available and relatively inexpensive. The requirement of
this paragraph respond to concerns of commenters regarding the hazards
of fuel storage underground.
Paragraph (b)(2) requires tethered or self-closing caps for
stationary tanks in permanent underground diesel fuel storage
facilities, and self-closing caps for diesel fuel tanks on diesel fuel
transportation units. The proposed rule would have required self-
closing caps for all diesel fuel storage tanks, and did not include the
alternative of a tethered cap for stationary tanks. One commenter
suggested that self-closing caps are not needed on fixed tanks since
they are unlikely to incur fuel spillage. The final rule permits the
optional use of a tethered cap for stationary tanks, which adds
flexibility and provides the same degree of protection as a self-
closing cap.
Paragraphs (b)(3), (b)(4), (b)(5), and (b)(6) are unchanged from
the proposal, with the exception of paragraph (b)(6) which has been
revised to reflect commenters' concerns with respect to the location of
shutoff valves. Paragraph (b)(3) addresses the size of vents, and will
permit the free flow of fuel out of the tank without creating a vacuum
in the tank that could damage its shell. Paragraph (b)(4) addresses
requirements for liquid tight connections, and will minimize the risk
of leaks and the resulting risk of fire. Paragraph (b)(4)(i) requires
that liquid tight connections for all tank openings be identified by
conspicuous markings that specify the function. Because this provision
is performance-oriented and allows the mine operator to choose the
manner in which markings identify connections, MSHA anticipates the
burden time under the Paperwork Reduction Act of 1995 to be minimal.
Paragraph (b)(5) addresses requirements for vent pipes, and will
minimize the possibility of fuel leaking from vent lines.
Paragraph (b)(6) is derived from proposed Sec. 75.1906(c)(5) and
requires that shutoff valves be located as close as practicable to the
tank shell. The proposal would have required shutoff valves to be
located within 1 inch of the tank shell. Because shutoff valves that
extend for any distance from the fuel tank can be inadvertently damaged
or broken off, making it impossible to shut off the flow of liquid from
the fuel tank, the valves must be located close to the tank where they
are protected from damage. However, one commenter was concerned that
the proposal was too restrictive because it may not always be possible
from a practical standpoint to locate the shutoff valve within 1 inch
of
[[Page 55451]]
the tank shell. The final rule responds to this commenter's suggestion
by allowing greater flexibility, and provides that the valve be located
as close as practicable to the tank shell.
Paragraph (b)(7) adopts the requirement of the proposal for an
automatic closing, heat-actuated valve on each withdrawal connection
below the liquid level. The final rule does not adopt the proposed
exception for connections used for emergency disposal, because this
exception is not relevant to underground coal mines. The proposed rule
required the installation of heat-actuated shutoff valves only on tanks
in fixed storage facilities. The final rule extends this requirements
to all diesel fuel tanks used underground, which would include tanks on
diesel fuel transportation units. Automatic closing, heat-actuated
valves shut the flow of fuel off when exposed to high temperatures.
These valves prevent additional fuel from being discharged from the
tank in the event of a fire. This requirement has been extended to
tanks on transportation units, and is warranted in light of the scaling
back of construction requirements for temporary fuel storage areas in
the final rule in response to commenters' concerns that the
requirements were impractical.
Paragraph (c) addresses tanks with openings for manual gauging, and
requires that liquid tight, tethered or self-closing caps or covers be
provided and be kept closed when not open for gauging. The alternative
of tethered caps or covers has been added to the final rule for
flexibility. MSHA believes the use of self-closing or tethered caps
will provide necessary protection against overflow.
Paragraph (d) requires that surfaces of the tank and its associated
components be protected against collision. This provision has been
added to the final rule in response to commenters who were concerned
about protecting the tanks from moving equipment. MSHA agrees that it
is essential that diesel fuel storage tanks be protected from damage by
collision with other equipment. Stationary tanks in permanent fuel
storage facilities may need guards or barricades, depending upon their
location, to prevent moving equipment from colliding with the tank.
Paragraph (e) sets forth requirements for leakage tests for tanks
and their associated components, except that tanks and components
connected directly to piping systems must be properly designed for the
application. The final rule requires a leakage test at a pressure equal
to the working pressure. The proposed rule would have required both a
strength test and a leakage test, at a pressure equal to the static
head, for diesel fuel storage tanks before the tanks were placed in
service. Commenters recommended that tanks and their connections be
tested at a pressure twice the working pressure.
The final rule does not require testing at twice the working
pressure, in light of the detailed construction and design requirements
for diesel fuel storage tanks in the final rule. The term ``static
head'' in the proposed rule has been replaced with the term ``working
pressure'' in the final rule. Although the meanings are the same in
this context, the term ``working pressure'' is more widely used and
more commonly understood in the mining industry. Compliance with the
requirement of this paragraph will provide protection from hazards
associated with leakage of diesel fuel underground. Under the final
rule, mine operators are expected to verify that no leaks exist after
installing the tank underground and connecting all of the tank's
associated components before placing the tank in service. All
components must be rated for the working pressures in the system. Both
the static head and the maximum pump pressure, if applicable, must be
considered when designing and selecting tanks and associated components
connected to a piping system. For tanks connected to a piping system
from the surface, the static head pressure could easily exceed several
hundred pounds per square inch (psi), either during normal operation or
because of a fault in the system. For these systems, MSHA advises mine
operators to plan for a worst-case (highest pressure) scenario and
select a tank and tank components that are designed for use at this
pressure.
MSHA has concluded that the strength test for tanks that was
included as part of the proposal is unnecessary, given the other
specifications for tanks. This proposed requirement has therefore not
been included in the final rule.
The proposal would have imposed additional requirements on tanks in
underground diesel storage facilities that were not located in ``dry
areas.'' Such tanks would have been required under the proposal to be
placed on noncombustible supports so that the tanks were at least 6
inches above water or wet bottom, and such tanks would also have been
required to be constructed of noncorrosive material. Commenters stated
that the concept of ``dry areas'' was ambiguous and should not be
adopted. MSHA agrees with these comments, and this aspect of the
proposal has therefore not been included in the final rule. However,
under the final rule, stationary tanks in permanent underground storage
facilities must be placed on noncombustible supports at least 12 inches
above the floor to allow for proper cleaning, rock dusting and quick
detection of leaks. Tanks will also be protected by this requirement
from wet floors. Further, the final rule requires all diesel fuel
storage tanks to be protected from corrosion. These requirements will
ensure that tanks are sufficiently shielded from water damage.
Paragraph (f) establishes design and size requirements for safety
cans. These requirements have been added to the final rule to ensure
that small amounts of diesel fuel can be transported and stored in a
safe manner. Although the proposed rule contemplated the use of safety
cans to transport small amounts of diesel fuel underground, the
proposal would not have set design requirements for safety cans.
Commenters were concerned that widespread and uncontrolled use of
safety cans underground would result in fuel spills and accumulations
on mine equipment and mine floors. The provisions of this paragraph are
intended to address commenters' concerns about the hazards presented by
safety cans used to store and transport diesel fuel in the underground
mine environment.
The final rule establishes specific design requirements for safety
cans. As indicated in the discussion of Sec. 75.1900, the term ``safety
can'' is defined in the final rule as a metal container intended for
storage, transport or dispensing of diesel fuel with a nominal capacity
of no more than 5 gallons, listed or approved by a nationally
recognized independent testing laboratory. Paragraph (f)(1) of this
section reiterates the 5-gallon capacity limitation, and paragraph
(f)(2) requires that safety cans be equipped with a flexible or rigid
tubular nozzle attached to a valved spout. Paragraph (f)(3) requires
that safety cans be provided with a vent valve designed to open and
close simultaneously and automatically with the opening and closing of
the pouring valve. Finally, paragraph (f)(4) requires that safety cans
be designed so that they will safely relieve internal pressure when
exposed to fire. These requirements will reduce the likelihood of
diesel fuel spills and afford appropriate protection for miners, in
response to commenters who were concerned about the use of safety cans
to store and transport diesel fuel.
[[Page 55452]]
Section 75.1905 Dispensing of Diesel Fuel
This section addresses the dispensing of diesel fuel, and has been
revised from the proposal to clarify the various ways that diesel fuel
may be safely dispensed. Paragraph (a) provides that diesel-powered
equipment may be refueled only from safety cans, from tanks on diesel
fuel transportation units, or from stationary tanks. These requirements
are intended to control the circumstances under which diesel fuel is
dispensed underground, minimizing the opportunities for spills or
leakage, and in response to commenters who expressed concern about fuel
spillage underground.
Paragraph (b) contains requirements for the dispensing of diesel
fuel from tanks, except for the dispensing of fuel from safety cans.
Design specifications for safety cans are included in Sec. 75.1904(f)
of the final rule, which requires nozzles, spouts, and vent valves on
safety cans.
The requirements of paragraph (b)(1) apply when gravity feed is
used as a means of dispensing diesel fuel. Although in developing the
proposed rule MSHA contemplated that gravity feed would be used as a
method for dispensing fuel, the proposal did not specifically refer to
it. Some commenters questioned whether this omission should be
interpreted as a prohibition of gravity feed fuel dispensing. In
response to these comments, MSHA has clarified that gravity feed is a
permissible method of dispensing fuel. However, because gravity feed
presents the same potential as a powered pump for a loss of fuel from
an unattended hose, the final rule prohibits a latch-open device when
gravity feed is the method of dispensing.
Paragraph (b)(2) is identical to the proposal and requires that a
manual pump used to dispense diesel fuel have a hose equipped with a
nozzle containing a self-closing valve. No comments were received on
this aspect of the proposal, and it has been adopted unchanged.
Paragraphs (b)(3) (i) through (iii) require that, when a powered
pump is used to dispense fuel, it be equipped with an accessible
emergency shutoff switch for each nozzle, and that the hose be equipped
with a self-closing valve without a latch-open device, and with an
anti-siphoning device. These requirements have been adopted, with some
minor changes, from the proposal. Specifically, the final rule
clarifies that an accessible emergency shutoff switch be provided for
``each nozzle'', and adds a requirement for an anti-siphoning device.
These modifications recognize that fuel piping systems may be installed
underground that do not transport fuel from the surface, but from one
location to another in the mine itself. These additional requirements
are intended to prevent the leakage or pumping of the contents of a
tank into the mine in the event of a broken or leaking pipe or hose. An
accessible emergency shutoff switch is required for each nozzle under
the final rule to permit quick action by mine personnel in the case of
a leaking pipe or hose or in the event of fire during refueling. An
anti-siphoning device prevents the inadvertent siphoning of fuel from a
tank connected to the piping system, and is responsive to commenters'
concerns regarding the hazards of fuel leaks and spills underground.
Commenters recommended that an inline fuse be required as near as
possible to the pump's power source to deenergize the electrical system
in the event of an electrical short circuit. This comment has not been
adopted in the final rule, because the circuit protection specified in
existing Sec. 75.518 is sufficient to prevent or detect a short
circuit. In addition, other existing electrical safety requirements in
part 75 apply to electrical components associated with diesel fuel
handling and storage, and provide adequate protection from electrical
hazards.
Paragraph (c) prohibits the use of compressed gas in dispensing
diesel fuel. This prohibition is identical to what was proposed and
received no comments. The use of compressed gas to dispense diesel fuel
would require not only a special tank but also an emergency venting
system for pressurized tanks, and would still present a hazard. If a
leak developed in the pressurized tank or its associated piping,
relatively large amount of fuel could be spilled onto the mine floor,
creating a serious fire hazard. This prohibition has therefore been
retained in the final rule.
Paragraph (d), like the proposal, prohibits diesel fuel from being
dispensed to the fuel tank of diesel-powered equipment while the
equipment engine is running. This prohibition is derived from MSHA's
review of Canadian fire accident data, which reveals that 10 fires
occurred during refueling. Failure to shut off the engine may have
contributed to these fires. This prohibition is also consistent with
Sec. 75.1916(d) of the final rule, which forbids unnecessary engine
idling, and reduces exposure of miners to exhaust emissions.
Several commenters recommended that permissible diesel equipment be
excluded from this prohibition because it is designed to be explosion-
proof. These commenters also stated that shutting down the equipment
should be avoided because of the difficulty in restarting it, and that
in some cases a trained mechanic would be needed to restart the engine.
MSHA does not agree that permissible equipment should be excluded
from this requirement. Although permissible diesel equipment is
equipped with engine surface temperature controls that would prevent
the ignition of diesel fuel if it is spilled on the equipment, air
quality considerations support the adoption of this requirement for
permissible as well as nonpermissible equipment. Not shutting down a
machine engine during refueling serves no purpose other than
convenience, and the diesel exhaust produced contributes unnecessarily
to contaminant levels. The fact that engines may be difficult to
restart does not justify exempting permissible equipment from this
requirement. Equipment that is difficult to restart is in need of
service or repair. The final rule therefore does not exempt permissible
equipment from the prohibition against refueling of diesel equipment
while the equipment engine is running.
Paragraph (e), which requires that powered pumps be shut off when
fuel is not being dispensed, has been added to the final rule to
address concerns about loss of fuel as a result of broken or leaking
pipes. This requirement is intended to minimize the likelihood of fuel
spills in the underground mine environment.
Section 75.1905-1 Diesel Fuel Piping Systems
Section 75.1905-1 has been added to the final rule to address
requirements for diesel fuel piping systems. The requirements in the
proposal governing fuel piping systems were included in the same
section as proposed requirements for fuel transfer. MSHA has concluded
that dispensing requirements and design and construction requirements
for piping systems are sufficiently unique that they are more
appropriately addressed in a separate standard.
Underground fuel piping systems can be very complex and may require
specialized expertise for their design and installation. Mine operators
should ensure that an engineering evaluation, including a fault
analysis, is performed in developing a fuel piping system.
One commenter recommended that piping of diesel fuel should be
allowed only in shaft mines, from the surface vertically to permanent
underground
[[Page 55453]]
storage areas, and that the piping should be contained in its own
borehole to isolate it from ignition sources. Safety considerations do
not warrant restricting fuel piping systems to shaft mines. MSHA and
industry experience, including an analysis of accident reports, does
not reveal any increased hazard with the use of piping systems in slope
mines. In the final rule, MSHA has removed the reference to vertical
pipelines to clarify that this section applies to all mines.
Paragraph (a) of this section of the final rule adopts the proposed
requirement that diesel fuel piping systems from the surface to be
designed and operated as dry systems, unless an automatic shutdown is
incorporated that prevents accidental loss or spillage of fuel and that
activates an alarm system. The phrase ``from the surface'' has been
added to the final rule to clarify that only piping systems from the
surface are governed by the requirements of this paragraph. MSHA is
aware that some mines have installed horizontal piping systems that do
not originate at the surface. Because these horizontal systems
typically cannot be operated as dry systems, the rule specifies that
these systems would not be affected by this requirement. No location is
specified for the alarm in the final rule, to allow mine operators
flexibility in determining where the alarm will be most effective in
alerting mine personnel.
Compliance with the requirement of this paragraph mandates a well
designed piping system, and may require a double wall system. Except
for the comment suggesting that piping of diesel fuel underground be
limited to shaft mines, MSHA received no other comments on this
provision, and the proposed requirement has been adopted in the final
rule without change.
Paragraphs (b)(1) through (b)(4) address requirements for piping,
valves, and fittings. These requirements are unchanged from the
proposal, and constitute generally accepted design specifications. This
standard requires that all piping, valves, and fittings be: (1) Capable
of withstanding working pressures and stresses; (2) capable of
withstanding four times the static pressure; (3) compatible with diesel
fuel; and (4) maintained in a manner which prevents leakage.
Paragraph (c) requires pipelines to have manual shutoff valves
installed at the surface filling point, and at the underground
discharge point. This requirement is the same as the proposal, except
that the proposal used the term ``vertical'' to describe pipelines. For
the reasons discussed in the introduction to this section, the term
``vertical'' has been eliminated to clarify that this section applies
to all underground coal mines.
Paragraphs (d) and (e), like the proposal, include requirements for
shutoff valves on fuel lines. Paragraph (d) provides that if fuel lines
are not buried in the ground, shutoff valves must be located every 300
feet. Paragraph (e) requires that shutoff valves be installed at each
branch line where the branch line joins the main line. One commenter
recommended that automatic shutoff valves be required in these two
situations, stating that they provide for minimal loss of fuel and
maximum safety in the case of a pipeline rupture or leak. MSHA does not
believe that automatic shutoff valves are necessary when the additional
benefits are balanced with other provisions in this final rule. The
commenter's suggestion has therefore not been adopted in the final
rule.
Paragraph (f) is a new provision in the final rule and requires
that an automatic means be provided to prevent unintentional transfer
of fuel from the surface into the permanent underground diesel fuel
storage facility. This requirement has been added to address the
concerns of some commenters that were prompted by a specific diesel
fuel spill caused by malfunctioning components in a diesel fuel piping
system. Additionally, many commenters were generally concerned about
possible fire and other hazards that could result from diesel fuel
spills and leaks, particularly when piping systems are used. This
paragraph responds to those comments by requiring a fail-safe piping
system, ensuring that necessary protection is provided to miners.
Paragraph (g) provides that diesel fuel piping systems from the
surface can only be used to transport fuel directly to stationary tanks
or diesel fuel transportation units in a permanent underground diesel
fuel storage facility. This requirement has been renumbered and has
been revised from the proposal to respond to commenters who recommended
strict control of the use of safety cans and stated that dispensing
fuel from a piping system directly into diesel equipment fuel tanks
would create a fire hazard. This paragraph is intended to prohibit
filling safety cans and equipment fuel tanks directly from a piping
system and further minimize hazards associated with fuel spills.
Under this paragraph a fuel piping system from the surface may
terminate underground only in a permanent fuel storage facility, which
must be equipped with features such as a fire suppression system and a
means of containing a fuel spill. Because temporary fuel storage areas
are not required to have these features, they would not provide
adequate fire protection for a situation where a significant amount of
fuel is lost in a spill from a piping system.
Paragraph (h), like the proposal, requires that when boreholes are
used the diesel fuel piping system cannot be located in a borehole with
electric power cables. This will minimize the likelihood of fire by
diesel fuel coming into contact with potential ignition sources.
Paragraph (i) requires that diesel fuel piping systems located in
entries not be located on the same side of the entry as electric cables
or power lines. It also requires that guarding be provided when piping
systems cross electric cables or power lines. The final rule has been
modified from the proposal to acknowledge that, in some cases, a
pipeline must cross over power lines, depending upon the mine's layout.
The standard addresses any hazards presented by the intersection of
pipelines and electric cables or power lines by requiring that guarding
be provided.
Paragraph (j) requires that piping systems be protected to prevent
physical damage. Commenters supported this provision, and it is
unchanged from the proposal.
Section 75.1906 Transport of Diesel Fuel
This section of the final rule has been retitled and reorganized to
reflect MSHA's approach to diesel fuel storage and handling in this
final rule. The word ``containers'' is removed from the title to
reflect that only two types of vessels are allowed to transport and
dispense diesel fuel--safety cans and tanks. This section of the final
rule is responsive to commenters who: expressed concerns about the wide
and uncontrolled use of safety cans in underground coal mines;
recommended limited section storage of diesel fuel; stated that fire
suppression systems were not needed on the tank used to transport fuel;
and noted the need for clarification of the requirement for portable
fire extinguishers on diesel fuel transportation units.
Several commenters stated that the proposed rule was vague and
confusing. Their comments were directed to the use of the terms
``containers,'' ``safety cans,'' ``tanks,'' and ``fuel transportation
units.'' As indicated in the preamble discussion for Sec. 75.1900, MSHA
has included definitions in the final rule for the terms ``safety
cans,'' ``diesel fuel tank,'' and ``diesel fuel transportation unit''
to provide additional clarification
[[Page 55454]]
for the fuel handling and storage requirements in the final rule. The
term ``container'' has not been defined because it has been eliminated
from the final rule.
Several commenters recommended that the use of small containers and
cans be restricted because they are prone to leak when transported or
used to dispense fuel. In support of their recommendation, these
commenters cited instances of mine floors being saturated with fuel.
Other commenters urged that safety cans be allowed for transport of
small quantities of diesel fuel, and stated that prohibiting their use
would be unwarranted. As stated earlier in the discussion for this
section, the final rule has been revised to require that safety cans be
listed or approved by a nationally recognized independent testing
laboratory. This aspect of the final rule will provide miners with
protection against leakage and spillage during dispensing operations,
while recognizing the practical need to transport small quantities of
diesel fuel.
Paragraph (a) of this section of the final rule requires diesel
fuel to be transported only by diesel fuel transportation units or in
safety cans. This requirement is intended to ensure that diesel fuel is
transported only in vessels designed for that purpose. The proposal
would have required diesel fuel to be transported in specially designed
containers. A commenter recommended substituting the term ``combustible
liquid'' in place of the term ``diesel fuel'', stating that there are
Department of Transportation specifications for containers that
transport combustible liquids. The final rule responds to commenters by
limiting the transport of diesel fuel to safety cans, which must be
listed or approved by a nationally recognized independent testing
laboratory, or by diesel fuel transportation units, which must be
equipped with a tank designed for the transport of diesel fuel.
MSHA recognizes that safety can use must be carefully controlled.
Paragraph (b) of this section of the final rule allows only one safety
can to be transported on a vehicle at any time, and the can must be
protected from damage during transport. All other safety cans must be
stored in permanent underground fuel storage facilities. This provision
is revised from the proposal to be responsive to commenters who cited
problems with misuse of small cans and recommended that they be
strictly controlled. Commenters further stated that in some mines there
was no designated area for storage of safety cans. The requirements
that have been added to the final rule are intended to ensure safe
transport of safety cans. The final rule does not require that single
safety cans, which are secured and protected on a vehicle, be removed
for storage in permanent facilities when the vehicle is left
unattended. This aspect of the final rule will allow for emergency
refueling, while at the same time provide a degree of control over the
use of safety cans.
Paragraphs (c) and (d) require that leaking safety cans be promptly
removed from the mine, and that safety cans and tanks on diesel fuel
transportation units be conspicuously marked. These marking
requirements are consistent with marking requirements for permanent
fuel storage facilities and temporary fuel storage areas in
Sec. 75.1903(b)(3) of the final rule. The inclusion of marking
requirements for safety cans and tanks in the final rule is responsive
to several commenters who suggested that signs should be placed on
mobile equipment identifying tanks and cans used for diesel fuel
storage. This is also a prudent fire protection practice.
Paragraphs (e) and (f) establish requirements for the
transportation of tanks on fuel transportation units. As mentioned
earlier, the final rule does not use the term ``container''. Paragraph
(e) provides that diesel fuel transportation units must not transport
more than 500 gallons of diesel fuel at one time. Paragraph (f)
requires tanks on diesel fuel transportation units to be permanently
fixed to the units and have a total capacity of no greater than 500
gallons. Under the proposal, containers used for the transport of
diesel fuel could not exceed a capacity of 500 gallons, and would have
been required to be permanently fixed to the transportation unit. One
commenter recommended that the maximum tank capacity be limited to 250
gallons, reasoning that less fuel would reduce the fire hazard. The
interrelated precautions of the final rule are designed to protect
against a fire involving a diesel fuel transportation unit. Reducing
the unit's fuel capacity to 250 gallons would not add significantly to
the protection against fire, and would increase the frequency with
which the unit would need to be refilled. However, paragraph (e) is
intended to limit the amount of fuel transported by a single trip,
either on rails or rubber tires, to 500 gallons. Paragraph (f) will
ensure that the fuel tank is not removed from the vehicle for transport
separately, thereby exposing the tank to possible damage, and also
offers some protection for the tank from the vehicle frame.
Paragraph (g) requires non-self-propelled diesel fuel
transportation units equipped with electric components for dispensing
fuel that are connected to a source of electrical power be provided
with a fire suppression device that meets the requirements of existing
Secs. 75.1107-3 through 75.1107-6, Secs. 75.1107-8, and Sec. 75.1107-
16. The proposed requirement would have required a fire suppression
system meeting the requirements of proposed Sec. 75.1911 on all diesel
fuel transportation units, not only on those with electrical
components.
Commenters were opposed to a requirement for fire suppression
systems on all diesel fuel transportation units, stating that a
trailer-mounted fuel tank did not need a fire suppression system since
it had no ignition source, and should not be treated any differently
than tanks transporting other combustible materials. These commenters
believed that the fire extinguishers required under the proposal would
provide adequate fire protection in temporary fuel storage areas.
MSHA agrees with commenters that fuel tanks alone, without an
ignition source, do not present a significant fire hazard. However,
fire protection for fuel tanks must be provided when a potential
ignition source exists. An ignition source is present on the diesel
fuel transportation unit when electrical power is provided to the
dispensing pump on the unit from either an electric-powered machine or
the mine electrical system. The final rule therefore requires fire
protection for non-self-propelled diesel fuel transportation units with
electrical components for dispensing fuel that are connected to a
source of electrical power. Diesel fuel transportation units with
electrical devices other than those used for dispensing fuel, such as
lights, do not present a significant fire hazard and do not need to be
protected by a fire suppression system. This fire suppression device
requirement would also apply when the transportation unit's dispensing
pump is powered by its own batteries or an off-board generator.
The final rule requires a fire suppression device meeting the
requirements of existing Sec. 75.1107, instead of Sec. 75.1911 under
the proposal, because the fire protection provided by Sec. 75.1107 is
suitable for electrical installations, and therefore appropriate for
electrical components of fuel transportation units. A fire suppression
system under Sec. 75.1911 is designed to protect diesel-powered
equipment, and,
[[Page 55455]]
unlike existing Sec. 75.1107, does not require that the mine electric
power supply to the fuel transportation unit be shut off when the fire
suppression system is actuated, an important safety feature that
prevents reignition of the fire.
Paragraph (h) requires diesel fuel transportation units and
vehicles transporting safety cans to have at least two multipurpose,
dry chemical type (ABC) fire extinguishers. The fire extinguishers must
be listed or approved by a nationally recognized independent testing
laboratory, and have a 10A:60B:C or higher rating. There must be at
least one fire extinguisher located on each side of the vehicle. The
proposal would have required that fire extinguishers be provided on
each end of a fuel transportation unit when diesel fuel was transported
in containers other than safety cans. Locating fire extinguishers on
the side is consistent with the requirements of Sec. 75.1911(e) of the
final rule for the location of fire suppression system actuators. The
type and size of extinguisher are the same as required by
Sec. 75.1903(b)(1) and (b)(2) for permanent underground diesel fuel
storage facilities and temporary underground diesel fuel storage areas.
Paragraph (i) requires that diesel fuel transportation units be
parked in permanent underground diesel fuel storage facilities or
temporary underground fuel storage areas when not in use. Under the
proposal, ``unattended'' diesel fuel transportation units would have
been required to be parked only in fixed or mobile fuel storage
facilities. Some commenters objected to this requirement, and urged
MSHA to provide a more workable rule that would allow transportation
units to be parked, consistent with the Advisory Committee's
recommendation that MSHA establish requirements for the temporary
parking of diesel transportation vehicles. Some commenters also stated
that ``unattended'' was an ambiguous term.
The term ``unattended'' has been eliminated from the final rule.
Instead, the final rule provides that diesel fuel transportation units
that are ``not in use'' must be parked either in permanent storage
facilities or temporary storage areas. The phrase ``not in use'' means
that the unit is not being trammed or used to dispense fuel or
lubricants or waiting to refuel another piece of equipment. It does not
mean that the unit operator must be within 500 feet or within the line
of sight of the fuel transportation unit, as long as the operator is
performing an activity associated with the operation of the unit. This
may occur, for example, while the operator is locating the next unit of
equipment to be refueled. This requirement is intended to control the
locations of diesel fuel transportation units to minimize fire hazards
associated with their use.
Paragraph (j), like the proposal, applies the requirements of
existing Sec. 75.1003-2 when the distance between a diesel fuel
transportation unit and an energized trolley wire at any location is
less than 12 inches. Section 75.1003-2 sets forth specific precautions
to be followed when off-track equipment is being moved in areas where
energized trolley wires are present. MSHA received no comments on this
aspect of the proposal and it has been adopted into the final rule
unchanged. This requirement is intended to minimize the risk of
ignition and fire when a diesel fuel transportation unit is in close
proximity to a bare energized trolley wire. The sparks and heat from an
electrical short circuit could ignite residual fuel on the
transportation unit and fire may then spread to the larger volume of
fuel stored on the transportation unit.
Paragraph (k) prohibits the transport of diesel fuel on or with
mantrips, or on conveyor belts. This requirement has been revised from
the proposal, which would have prohibited transport of diesel fuel on
conveyor belts, to include within the prohibition the transport of
diesel fuel on mantrips, in response to several commenters who
expressed concern about transportation of diesel fuel on personnel
carriers because of the inherent hazards associated with that practice.
This requirement applies to equipment being used as personnel carriers,
but does not apply to such equipment when it is used for purposes other
than transporting miners in the mine. This requirement also does not
apply to diesel fuel contained in the fuel tank of a diesel-powered
personnel carrier.
Paragraph (l) requires that, as of 12 months after the publication
date of the final rule, diesel fuel must be stored and handled in
accordance with the requirements of Secs. 75.1902 through 75.1906 of
this part. Twelve months will provide sufficient time for mine
operators to make any necessary changes to their fuel handling,
transportation, and storage practices underground, such as fuel tank
retrofits or construction of fuel storage facilities. The requirements
of Sec. 75.1903 (c) and (d) take effect sooner, because they address
safe welding practices in or near diesel fuel storage areas, and mine
operators should not need any additional time to come into compliance
with these provisions.
Section 75.1907 Diesel-Powered Equipment Intended For Use In
Underground Coal Mines.
This section establishes a schedule for compliance with the final
rule's equipment-related requirements, including requirements for
approved engines and power packages, fire suppression systems, and
safety-related requirements for nonpermissible equipment in
Secs. 75.1909 and 75.1910. The concept of a time schedule to allow for
conversion or replacement of diesel-powered equipment currently in use
to comply with the new requirements of the final rule was recommended
by the Diesel Advisory Committee. The Committee also recommended that
equipment newly introduced underground after a fixed date meet the new
requirements.
Under the compliance schedule of this section, 30 days after the
rule's publication date all diesel-powered equipment used where
permissible electric equipment is required must be approved under part
36. This section also establishes a compliance schedule for Part 36-
approved equipment, to comply with certain surface temperature limits
within 6 months, and be provided with a fire suppression system and
brakes that meet certain standards within 36 months of the rule's
publication. Part 36-approved equipment is also required to have a
particulate index and a dilution air quantity determined under subpart
E of part 7 within 12 months of the rule's publication date.
Permissible diesel-powered equipment that is manufactured 3 years after
the date of publication of the final rule or later and used in
underground coal mines must incorporate a power package approved under
subpart F of part 7 of the final rule. This section of the final rule
also requires nonpermissible diesel-powered equipment, with the
exception of the special category of ambulances and firefighting
equipment under Sec. 75.1908(d), to be equipped with the machine safety
features set forth in Secs. 75.1909 and 75.1910 within 36 months of the
publication date of the final rule.
The overall approach taken in the final rule for equipment safety
features is different from that of the proposal, in response to
commenters and for reasons explained in detail in the preamble for
parts 7 and 36. The proposed rule would have required approval of fully
assembled permissible equipment under subpart H of part 7, and approval
of fully assembled nonpermissible
[[Page 55456]]
equipment under subpart I of part 7. A limited class of light-duty
nonpermissible equipment would have been established that did not
require fully assembled machine approval, but which would have been
equipped with specific machine safety features set forth as mandatory
standards in proposed Sec. 75.1909. Under proposed Sec. 75.1907,
specific deadlines, up to 60 months after the rule's effective date,
would have been set for compliance with the equipment-related
requirements of the final rule for both permissible and nonpermissible
equipment, including limited class and stationary unattended equipment.
Additionally, the proposal would have allowed a mine operator to apply
for MSHA approval for continued use of diesel-powered locomotives
without required subpart F or G power packages. MSHA would have been
authorized to grant such approval if approved power packages suitable
for specific mine conditions and locomotive design were not available,
recognizing that the current state of technology might make compliance
difficult or impossible.
The proposed rule took the approach of phasing in the different
equipment-related requirements, depending on how long MSHA determined
mine operators and manufacturers would need to obtain the necessary
equipment or make the necessary retrofits, including time needed to
obtain MSHA approval for the appropriate machine components.
Specifically, the proposed rule would have allowed a longer period of
time for equipment to be provided with approved engines and power
packages than it would have allowed for other equipment-related
requirements, for such features as brakes, fuel systems, and electrical
components. Different time frames would have been allowed under the
proposal to take into account the time needed for the MSHA approval
process as well as the technical difficulties associated with
retrofitting equipment with approved power packages and engines.
As discussed in the preamble to part 7 of the final rule, the final
rule does not adopt the approach of fully assembled machine approval
under subparts H and I of part 7 contemplated by the proposal and
addressed in the concurrent advance notice of proposed rulemaking.
Instead, part 36 has been expanded to specifically provide for approval
of diesel-powered equipment used in areas of underground coal mines
where permissible electric equipment is required. Fully assembled
machine approval is not required under the final rule for any category
of nonpermissible equipment. The compliance time frames of this section
of the final rule reflect this change in approach.
The time frames in this section are based on an estimation of the
useful life of existing diesel-powered equipment, the reasonable time
needed to convert or retrofit existing equipment, and the commercial
availability of suitable replacement equipment. The time frames in this
section are intended to provide mine operators with a reasonable period
of time to make determinations of the expected remaining useful life of
diesel-powered machines in use in their mines and the cost of necessary
machine modifications, and to compare this information with the
replacement cost of equipment that complies with the requirements of
the final rule.
One commenter rebuilt a diesel-powered truck to convert it to a
personnel carrier that met the equipment safety requirements of the
proposed rule for self-propelled limited class nonpermissible
equipment, and submitted a written summary documenting the conversion
into the rulemaking record. This information generally demonstrated
that compliance would be facilitated if equipment-related requirements
were phased in by equipment type, rather than phasing in specific
requirements across all equipment types. In short, once an equipment
rebuild is initiated, it is easier to perform all machine feature
modifications at the same time.
One commenter asserted generally that mine operators and equipment
manufacturers could bring diesel-powered equipment into compliance with
the requirements of the final rule within 12 months. Although MSHA
agrees, and the final rule reflects, that some requirements can be met
within a year, compliance with other requirements, will reasonably
involve more time.
As explained in greater detail elsewhere in the preamble, the final
rule requires specific safety features on both permissible and
nonpermissible diesel-powered equipment. These requirements apply to
nonpermissible diesel-powered equipment in Secs. 75.1909 and 75.1910,
and will be applied to permissible diesel-powered equipment during the
MSHA approval process under part 36.
The final rule does not require nonpermissible equipment to be
provided with power packages, which would have been required under the
proposal. Neither does it require fully assembled machine approval for
nonpermissible equipment. Power packages would have provided this
equipment with, among other things, surface temperature controls for
the equipment. As discussed elsewhere in the preamble, commenters were
divided on this issue. Some commenters believed not only that
temperature controls were necessary to adequately address the fire
hazards presented by diesel-powered equipment underground, but also
recommended that all diesel-powered equipment be approved under part 36
as permissible, and provided with the explosion-proof features required
on such equipment. Other commenters strenuously opposed a requirement
for approved power packages on nonpermissible equipment, stating that
surface temperature controls were not needed on equipment operated
outby the face, and that fire protection features, such as fire
suppression systems, in conjunction with other machine safety features
would provide an appropriate margin of safety. These commenters stated
that a power package requirement for nonpermissible equipment would
have the effect of eliminating many useful pieces of equipment from
mines that could not be retrofitted with power packages or would not be
manufactured with them.
The final rule does not require approved power packages on outby
equipment, except when the equipment discharges its exhaust directly
into a return air course, as provided under Sec. 75.1909. Proposed
subpart G, which would have established an approval program for power
packages for nonpermissible equipment, has not been adopted in the
final rule. Instead, nonpermissible equipment is required under
Sec. 75.1909(a)(10) to be provided with a means to prevent the spray
from ruptured hydraulic or lubricating oil lines from being ignited by
contact with engine exhaust system component surfaces. This requirement
recognizes that the hazards of high surface temperatures on diesel-
powered equipment can be controlled in a number of ways in addition to
the methods contemplated under proposed subpart G. MSHA has concluded
that the requirement of paragraph (a)(10), along with the other safety
features required for control of fuel sources on diesel-powered
equipment, provides effective fire prevention on nonpermissible diesel-
powered equipment. The approach of the final rule allows mine operators
and manufacturers the flexibility to improve existing methods and to
develop new methods of meeting the performance goals of the final rule
requirements.
Paragraph (a) of this section of the final rule adopts the proposed
requirement that within 30 days of the date of publication of the final
rule, all
[[Page 55457]]
diesel-powered equipment used where permissible electrical equipment is
required be approved under part 36. Part 36 approval ensures that the
equipment is explosion-proof, and that equipment used in areas of the
mine where methane is likely to accumulate and where there may be
combustible quantities of coal dust and other materials will not cause
a fire or an explosion. All underground coal mines using diesel
equipment already have the approved equipment necessary to comply with
this requirement, in most cases because the mine's ventilation plan
specifically requires it. This requirement therefore goes into effect
30 days after publication of the final rule, providing necessary
protections for miners working underground.
Paragraph (b) establishes a time schedule under which equipment
approved under part 36 is required to be provided with additional
safety features. Paragraph (b)(1) requires the equipment to be provided
with a safety component system that limits surface temperatures to
those specified in subpart F of part 7. This requirement is essentially
identical to that of the proposal, which would have required that part
36-approved equipment be provided with a power package that limits
surface temperatures to those specified in subpart F. In the final
rule, the equipment is required to have a ``safety component system''
that limits the surface temperatures rather than a ``power package''
specified under the proposal. Existing permissible equipment has been
approved under the current version of part 36, which uses the term
``safety component system'' to refer to those devices added to the
engine to control surface temperatures of the exhaust system. The term
``power package'' used in the final rule includes those devices, which,
with the engine, comprises the ``power package.'' Power packages are
approved under subpart F of part 7 of the final rule. As discussed
elsewhere in this preamble, part 36 has been specifically revised to
provide for approval of diesel-powered machines used in underground
coal mines. Part 36 now references subparts E and F of part 7 of the
final rule, and requires equipment approved under part 36 for use in
coal mines to be equipped with a power package approved under subpart
F. Subpart F limits the maximum surface temperature to less than
302 deg. F (150 deg. C). Until promulgation of this final rule, the
maximum surface temperature of the engine and exhaust system components
under part 36 was 400 deg. F (204 deg. C). To date, only one engine and
safety component system used in part 36-approved equipment has a
surface temperature above 302 deg. F, and the equipment on which the
system is installed is not used in coal mines. Consequently, compliance
with this requirement within six months of the publication of the final
rule should present no compliance difficulties for mine operators or
manufacturers. This requirement will ensure that permissible equipment
in underground coal mines will have surface temperatures below 302 deg.
F, minimizing the chance that combustibles such as diesel fuel, float
coal dust, and hydraulic fluid will be ignited by high surface
temperatures.
Paragraph (b)(2) requires that, as of 36 months after the final
rule is published, equipment approved under part 36 be provided with an
automatic or manual fire suppression system that meets the requirements
of Sec. 75.1911, and be provided with a portable fire extinguisher. A
fire suppression system is required on permissible equipment in
addition to surface temperature controls to address fire hazards
created by other machine system malfunctions. The fire suppression
system on permissible equipment may be either manual or automatic.
Under the proposal, part 36-approved equipment would have been required
to have a fire suppression system that met the requirements of
Sec. 75.1911. The requirements of proposed Sec. 75.1911 provided only
for automatic fire suppressions systems. For reasons explained in
greater detail in the preamble discussion to Sec. 75.1911, automatic
fire suppression is not required on permissible diesel-powered
equipment. This is because all equipment approved under part 36 is
provided with surface temperature controls, which reduce the risk of
fire. The final rule includes the additional requirement that the
equipment be provided with at least one portable multipurpose dry
chemical type ABC fire extinguisher having a 10A:60B:C rating or
higher. The fire extinguisher must be located within easy reach of the
equipment operator and be protected from damage by collision. This
requirement has been added in response to the recommendation of a
commenter. MSHA has concluded that requiring equipment to be provided
with a portable fire extinguisher is a good fire prevention practice,
and this recommendation has therefore been adopted in the final rule,
superseding the requirement in part 36 for a fire extinguisher with a
much lower firefighting rating. This requirement is consistent with the
fire extinguisher requirements for nonpermissible equipment in the
final rule.
MSHA had proposed a 6-month compliance deadline for installation of
fire suppression systems on part 36-approved equipment, but has
concluded that a 36-month time frame is needed for mine operators to
obtain MSHA approval of field modifications on approved equipment, and
for equipment manufacturers to process approval applications to permit
installation of fire suppression systems on permissible equipment. The
Agency intends to promptly process approval applications for
modification of machines to aid compliance with this requirement.
Paragraph (b)(3) has been added to the final rule to require that,
as of 36 months after the publication date of the final rule, equipment
approved under part 36 be provided with brake systems that meet the
requirements of Sec. 75.1909(b)(7), (b)(8), (b)(9), (c), (d), and (e).
These brake requirements have been added to ensure that permissible
equipment meets at least the same braking requirements as
nonpermissible equipment under the final rule. All existing part 36
equipment is already equipped with service brake systems that meet the
requirements of Sec. 75.1909(b)(8), (b)(9), and (d). The requirements
of Sec. 75.1909(c) have been developed from requirements for automatic
emergency parking brakes on electric equipment in Sec. 75.523-3. A
number of commenters supported the application of these requirements to
diesel-powered equipment, and they have been applied to permissible
equipment under the final rule. Some existing part 36-approved
equipment will require minor modifications to comply with the
requirements of Sec. 75.1909(c). Section 75.1909(b)(7) essentially
requires independent service brake systems for the front and rear
wheels of vehicles. This is a well-recognized safety feature that is
warranted for part 36-approved diesel-powered equipment as well as for
nonpermissible equipment covered by Sec. 75.1909. Although the majority
of part 36-approved equipment is already provided with this feature, a
limited number of machines will require modification. Because some mine
operators will need to obtain field modifications and equipment
manufacturers must obtain MSHA approval of design modifications, a 36-
month compliance time is appropriate and is provided for in the final
rule.
Section 75.1909 of the final rule requires that nonpermissible
diesel-powered equipment be equipped with a supplemental brake system,
which provides substantially the same features as would be provided by
the automatic emergency parking brakes specified in
[[Page 55458]]
Sec. 75.523-3. Section 75.1909(e) requires setting of the supplemental
brake system when the operator is not at the controls of the equipment,
except during the movement of disabled equipment. Because part 36-
approved equipment is provided with a supplemental brake system under
the final rule, the requirement for setting of the supplemental brake
has also been applied to this equipment.
Paragraph (b)(4) requires that equipment approved under part 36
have a particulate index and a dilution air quantity determined in
accordance with part 7, subpart E within 12 months of the publication
date of the final rule. The types of engines that are affected by this
requirement are installed in permissible face equipment that is
currently approved under part 36. Because of where and how this
equipment is used, it significantly affects the air quality where
miners work and travel. Diesel-powered face equipment includes haulage
equipment and roof bolters, which are typically used in the confined
environment in the production area of the face and operated almost
continuously over the course of a shift. The contribution of diesel
exhaust from this equipment into the mine atmosphere can be significant
and can adversely affect the health conditions for miners working in
and around the area where the equipment is being operated. Under new
requirements in Sec. 75.325 of the final rule, minimum ventilating air
quantities are established for areas where diesel-powered equipment
operates. These minimum quantities are derived from the approval plate
ventilating air quantity for the equipment that is operating.
Consequently, ventilating air quantities must be calculated for these
engines so that the minimum air quantity requirements can be
implemented. As mentioned elsewhere in this preamble, the particulate
index will not be used to determine the minimum ventilating air
quantity for the engine, but will be available for informational
purposes.
There are only four engines models used in the majority of part 36-
approved equipment used in underground coal mines. These engines are
typically of older design, and it is uncertain whether the engine
manufacturers will seek approval for their engine designs under subpart
E of part 7. As a result, MSHA intends to determine dilution air
quantities and particulate indices for these engines in accordance with
part 7, subpart E, whether or not the manufacturers seek a subpart E
approval for their engines. MSHA will make this information available
to mine operators, which must be applied and implemented within 12
months of the date of the final rule's publication. This time frame is
consistent with the 12-month effective date for compliance with the
ventilation requirements of Sec. 75.325(k) of the final rule that apply
where diesel-powered equipment is operated.
Paragraph (b)(5) requires that permissible diesel-powered equipment
that is manufactured 36 months or more after the publication date of
the final rule and used in an underground coal mine incorporate a power
package approved under part 7, subpart F. Under the proposal, only
``new'' diesel-powered equipment approved under subpart H or I or
meeting the requirements of Secs. 75.1909 and 1910 could be introduced
into underground coal mines 60 months after the effective date of
Sec. 75.1907. This meant that both new permissible and nonpermissible
equipment (that did not fall into the limited class or was not used as
stationary unattended equipment) introduced in an underground coal mine
after the deadline would have had to receive a full machine approval.
One commenter recommended that the proposed 60-month delayed effective
date be changed to 12 months. Another commenter suggested that the
language be clarified to state that existing part 36 approvals remain
valid.
The time frame for compliance has been reduced to 36 months in
recognition of the fact that the final rule does not require full
machine approval of all permissible and nonpermissible equipment, as
contemplated by the proposal. Three years should be sufficient for
equipment manufacturers to obtain approval for and incorporate subpart
F power packages into the permissible diesel-powered equipment they
manufacture. Part 36-approved equipment manufactured before the
relevant date may continue to be used in accordance with its approval
indefinitely.
Paragraph (c) requires nonpermissible diesel-powered equipment to
comply with Secs. 75.1909 and 75.1910 within 36 months of the
publication date of the rule. Under the final rule nonpermissible
equipment, which is used in areas where permissible electric equipment
is not required, does not need full machine approval by MSHA. However,
under Sec. 75.1909(a)(1) nonpermissible equipment must be equipped with
an engine approved under subpart E of part 7. The final rule did not
adopt the proposed establishment of a limited class of nonpermissible
light-duty equipment, for reasons explained in detail in the preamble
to Sec. 75.1908. Instead, the final rule establishes two categories of
nonpermissible equipment, heavy-duty and light-duty. Under paragraph
(c) of this section of the final rule, equipment in both categories
must be provided with the safety features set forth in Secs. 75.1909
and 75.1910. These features include engines approved under subpart E of
part 7, fire suppression systems, brakes, and electrical protections.
Several commenters stated that approved engines, power packages, or
surface temperature controls are unnecessary for nonpermissible
equipment, while other commenters considered surface temperature
controls necessary.
The final rule's equipment safety requirements for nonpermissible
diesel-powered equipment are intended to ensure that the equipment will
not present a fire hazard and that gaseous diesel exhaust emissions and
particulate emissions are addressed.
A compliance time of 24 months was proposed, and one commenter
recommended a 12-month compliance time. The final rule allows 36 months
for nonpermissible equipment to comply with the requirements of
Secs. 75.1909 and 75.1910. Included in these sections is a requirement
that nonpermissible equipment be provided with an engine approved under
subpart E of part 7. It is expected that this requirement will require
the longest time period for compliance, as engine manufacturers must
first obtain MSHA approval of appropriate engines. The 36-month time
frame allows some models of nonpermissible equipment currently in use
in underground coal mines to reach the end of its useful life and to be
replaced with equipment that meets these requirements, rather than
being retrofitted with a new engine and the other features required by
Secs. 75.1909 and 75.1910.
The final rule does not adopt the proposed provision allowing mine
operators to seek MSHA approval for the extended use of diesel-powered
locomotives because of the unavailability of approved power packages
suitable for the mine conditions or for the locomotive's design. This
provision recognized that certain types of diesel locomotives might not
have been able to be retrofitted to meet all of the applicable
equipment-related requirements. Because the final rule does not require
approved power packages for nonpermissible equipment, a process for
MSHA approval of extended use of nonpermissible locomotives without
approved power packages is no longer
[[Page 55459]]
necessary, and has consequently not been adopted in the final rule.
Section 75.1908 Nonpermissible Diesel-Powered Equipment; Categories
This section of the final rule establishes three categories of
nonpermissible diesel-powered equipment: heavy-duty equipment, which is
defined as equipment that is used for such tasks as cutting or moving
rock or coal, drilling or bolting, or moving longwall components;
light-duty equipment, which includes any other nonpermissible equipment
that is not heavy-duty; and a special category for ambulances and fire
fighting equipment. Because nonpermissible equipment is used in areas
of the mine where methane is not likely to accumulate, it is not
required to be explosion-proof. However, all nonpermissible equipment,
with the exception of ambulances and other emergency equipment
described under paragraph (d), is required to have an engine approved
under subpart E of part 7, which sets engine performance and exhaust
emissions requirements.
The requirements that apply to nonpermissible equipment under the
final rule vary according to the equipment's category. Most
importantly, the equipment category determines which equipment safety
features are required under Secs. 75.1909 and 75.1910 of the final
rule. One of the most important distinctions between heavy-and light-
duty equipment under the final rule is that heavy-duty equipment is
required to have an automatic fire suppression system under
Sec. 75.1909, while light-duty equipment may be provided with either a
manual or automatic system. Additionally, heavy-duty nonpermissible
equipment is subject to the weekly undiluted exhaust emissions test
under Sec. 75.1914(g) of the final rule, and must also be included in
the air quantity calculation for multiple units of diesel-powered
equipment under Sec. 75.325(g). These provisions do not apply to light-
duty equipment.
The final rule is a significant departure from the proposal, in
response to a majority of commenters who were opposed to the proposed
criteria for the equipment categories. The proposal would have
established a special category of nonpermissible ``limited class''
equipment. Limited class equipment under the proposal would have been
equipment weighing less than 6,000 pounds and equipped with an engine
of less than 90 horsepower. Equipment with a hydraulic system could not
be included in the limited class, although MSHA stated in the preamble
to the proposal that this restriction was not intended to apply to
hydraulic systems used in brake units or automotive-style power assist
units. Additionally, the equipment engine could not be turbocharged.
Portable equipment that fell into this class was limited to welders and
compressors. The proposal also allowed altitude compensation devices to
be used with limited class equipment.
Although limited class equipment under the proposal would have been
required to have an engine approved under subpart E of part 7, the
machine as a whole would not have been approved by MSHA. Instead,
limited class equipment would have been required to be equipped with
the safety features in proposed Sec. 75.1909. All other nonpermissible
equipment would have been required to have a subpart F or G approved
``power package,'' which would have included an approved engine with
additional components to prevent the ignition of methane or combustible
materials, such as surface temperature controls. Additionally, it was
MSHA's intention, reflected in the advance notice of proposed
rulemaking published with the proposal, to require whole machine
approval of all nonpermissible equipment, except equipment that fell
into the limited class defined under the proposal.
The equipment categories in the proposed rule were based upon the
Diesel Advisory Committee recommendation that fire prevention features,
including surface temperature controls and fire suppression systems, be
required on all outby equipment. However, the Committee recognized that
much of the light-duty equipment in use in mines was not specifically
designed for mining and might not be available with surface temperature
controls. The Committee therefore concluded that a limited class of
light-duty equipment could be safely operated if it was equipped with
fire prevention and protection features in lieu of surface temperature
controls, such as fire suppression devices, reduction of the potential
for fuels to contact hot surfaces, and reduction of potential ignition
sources. Equipment in this limited class would be expected to operate
on a light-duty cycle, and would not reach high temperatures or would
reach high temperatures for a limited period of time, with a
significantly reduced potential for fire.
Commenters expressed widely varying views on this aspect of the
proposal. Most commenters supported the concept of a distinct class of
equipment with less extensive safety requirements, but many stated that
the criteria in the proposal for limited class equipment were
unnecessarily restrictive, and that the class should be significantly
broadened to include many more types of equipment, such as light-duty
manned personnel and material haulage equipment. A number of commenters
indicated that the equipment that they would consider light-duty
equipment in their mines exceeded either the weight or horsepower
restrictions of the proposal.
Other commenters were of the opinion that fire suppression systems
were an acceptable substitute for surface temperature controls, and
strongly supported a significant expansion of the equipment falling
into the limited class and therefore not required to have a power
package that would provide such controls. A number of commenters also
indicated that much of the equipment currently in use in mines that did
not fall into the proposed limited class would have to be replaced,
because it would be impossible to retrofit the equipment to provide the
required surface temperature controls. Other commenters were concerned
that limitations based on existing equipment designs could discourage
the development of new technology.
One commenter was generally opposed to the creation of a limited
class that was not required to have surface temperature controls,
because the commenter believed that this would present an unacceptable
fire hazard. This commenter stated that heat sensors that triggered
engine shutdown or fire suppression were not acceptable substitutes for
surface temperature controls.
A number of commenters were opposed to the limitation on equipment
weight, stating that weight had no relationship to the hazards
presented by the equipment, and that the 6,000-pound restriction was
arbitrary. One commenter stated that although weight in some cases
could be an indicator of duty cycle and the potential for higher
equipment operating temperatures and resulting fires, requirements for
fire suppression and automatic engine shutdown when engine temperature
reaches a specified limit would adequately address these concerns.
Another commenter stated that most diesel equipment that exceeds 6,000
pounds is not used in heavy-duty applications such as coal production
but is considered light-duty equipment.
Some commenters were particularly concerned about the safety impact
of the weight limitation on railmounted equipment, pointing out that
weight is needed to provide traction. These commenters stated that
although some
[[Page 55460]]
rail-mounted equipment would fall below the proposed horsepower
limitation, the weight of most rail-mounted equipment significantly
exceeds 6,000 pounds, and that it would be neither practical nor
feasible to modify existing outby track equipment to meet the proposed
limited class criteria. Because of this concern, one commenter
suggested that outby rail-mounted equipment be addressed in a separate
category, without a weight restriction.
Several commenters also stated that the safety features that would
be required on limited class equipment under proposed Sec. 75.1909
would add to the vehicle weight, making the 6,000-pound restriction
even more unrealistic in those commenters' opinion. One commenter
estimated that equipment retrofits for safety features and for mine-
worthiness would increase equipment weight by at least 50 percent.
Another commenter suggested that the proposed weight limitation would
result in overloading equipment units because of light construction.
Some suggested that the weight limitation for limited class equipment
be increased to 7,500 or 8,500 pounds; others recommended that the
limit be increased to 14,000 to 15,000 pounds, to permit units to be
manufactured with heavy steel to withstand collisions. One commenter
recommended that the weight limitation be reduced to 4,000 pounds for
self-propelled equipment.
A number of commenters were also opposed to the 90-horsepower
limitation, stating that engine horsepower was no more an indication of
whether equipment was heavy-duty or light-duty than was equipment
weight. However, one commenter recommended that the limitation be
reduced to less than 70 horsepower.
Commenters were also concerned about the prohibition against
hydraulic systems on limited class equipment. Several commenters stated
that there was no basis for excluding equipment with hydraulic systems
from the limited class, except for the fact that hydraulic fluid could
present a fire hazard. These commenters suggested that equipment with
hydraulic systems that utilized fire-resistant hydraulic fluid should
be permitted. Some of these commenters also suggested that equipment
with hydraulic systems should be eligible for the limited class
category if the equipment is equipped with a fire-suppression system.
Other commenters stated that equipment with hydraulic systems had not
been shown to be less safe than equipment without such systems. Some
pointed out that hydraulic systems facilitate the handling of supplies
and materials, making the job easier and safer. These commenters also
believed that prohibiting hydraulic systems on limited class equipment
would preclude other equipment features that enhance safety, such as
power take-offs, automatic transmissions, and hydrostatic drive units.
Commenters were also opposed to the prohibition against
turbocharged engines for limited class equipment. This restriction was
included in the proposal because of the concern about the potential
ignition of combustible materials on the hot exhaust system surfaces
that are characteristic of turbocharged engines. Commenters stated that
turbochargers have served as an effective means of yielding greater
horsepower from smaller engines and should be allowed on limited class
equipment, and that the exhaust components could be encased in
protective insulating material to eliminate any fire hazard.
A number of commenters expressed concern that manufacturers of
equipment that was not specifically designed for use in mines would not
seek MSHA approval for their equipment because the share of the market
for mining applications was too small to warrant the expense of
developing power packages.
A number of commenters stated that inclusion of equipment in a
limited class should depend on how the equipment is being used rather
than on factors such as size and weight. Some of these commenters
suggested that light- duty equipment include equipment that does not
move rock, coal, or longwall shields. Other commenters advocated that
all diesel-powered equipment, including limited class equipment, be
designed to be explosion-proof and be approved by MSHA under part 7.
These commenters felt that establishing a limited class of light-duty
equipment would allow mine operators to use equipment with inferior
means of fire prevention.
One commenter recommended that a determination of the equipment
included in the limited class should be based on MSHA's evaluation of
diesel equipment fire experience in other industries and in other
countries as to which types of equipment do and do not pose a
significant fire hazard. In response to this comment, MSHA acquired
accident reports from the Ministry of Labor, Province of Ontario,
Canada, containing detailed information of fires on diesel-powered
equipment in underground mines in Ontario for the years 1984 through
1992. This information was carefully analyzed to determine which
machine safety features and what type of equipment design are needed to
prevent fires on diesel-powered equipment used in underground coal
mines. An analysis of the Ontario fire data reveals that equipment used
in heavy-duty type activities, such as hauling rock or coal or moving
longwall components, presents a significant fire hazard and requires
suitable fire prevention and protection features.
Consistent with these conclusions and also with the recommendations
of a number of commenters, paragraphs (a)(1) through (a)(5) of this
section of the final rule specify what constitutes heavy-duty
equipment. Heavy-duty nonpermissible equipment includes equipment that
cuts or moves rock or coal; equipment that performs drilling or bolting
functions; equipment that moves longwall components; self-propelled
diesel fuel transportation units and lube units; and machines used to
transport portable fuel transportation units or lube units. These
machines are intended to move rock or coal or other heavy loads, such
as longwall components, or move large quantities of combustible diesel
fuel as a normal part of their duty cycle. Locomotives used to
transport rock or coal and portable diesel fuel transportation units or
lube units would also be in the heavy-duty equipment category under the
final rule. Graders would also be considered heavy-duty equipment,
because they are used to move rock or coal.
Equipment falling within the heavy-duty equipment category under
paragraph (a) is typically used for extended periods during a shift on
a continuous, rather than intermittent, basis. This is in contrast to
equipment that is used for limited periods during a shift, such as
mantrips or supply vehicles. Heavy-duty equipment under the final rule
also moves heavy loads or performs considerable work as in the case of
drilling machines. Equipment used to haul longwall components is
typically operated at a consistently accelerated pace under an
extremely heavy load. Fuel transportation units and lube units
generally are larger machines specially designed to transport and
dispense diesel fuel, hydraulic fluid, grease, oil, and other
combustible materials. This equipment also operates under a heavy load
and typically moves constantly around a section during the course of a
shift, refueling equipment as needed. Equipment that performs drilling
and bolting functions generally has an engine that runs at a high rate
of speed and powers large hydraulic systems. Under the final rule
heavy-duty
[[Page 55461]]
equipment must be provided with an automatic fire suppression system,
addressing the additional fire risks resulting from the way this
equipment is used. Heavy-duty equipment also produces greater levels of
gaseous contaminants, and under the final rule is therefore subject to
weekly undiluted exhaust emissions tests under Sec. 75.1914(g), and is
included in the air quantity calculation for ventilation of diesel-
powered equipment under Sec. 75.325(g).
Under paragraph (b) light-duty equipment is defined as any other
diesel-powered equipment that does not meet the criteria of paragraph
(a). This is in contrast to the approach taken in the proposed rule
establishing a limited class of light-duty equipment. Light-duty
equipment under the final rule may include, but is not limited to,
forklifts used to carry supplies, rock dusting machines, tractors not
used to move rock or coal, supply trucks, water trucks, personnel
carriers, jeeps, scooters, golf carts, and pickup trucks. The equipment
may be rubber-tired, crawler-mounted, or rail-mounted.
Under the final rule two machines of the same model could fall into
different equipment categories, depending on how they are used. For
example, a load-haul-dump unit used to move rock or coal would be
considered heavy-duty equipment, while an identical machine used
exclusively to move supplies would be a light-duty machine, subject to
different requirements. Although these machines are of the same design,
they do not present the same risk of fire because of the way they are
used. They also do not produce the same quantities of exhaust
contaminants: machines that are operated for extended periods of time
under heavy load generate more contaminants than machines that are not.
Equipment that is classified as light-duty may not be used, even
intermittently, to perform the functions listed in paragraphs (a)(1)
through (a)(5). This is because equipment that performs heavy-duty
functions poses an increased fire risk, resulting in the need for an
automatic fire suppression system, as required under Sec. 75.1909 for
heavy-duty equipment. On the other hand, heavy-duty equipment may be
used to perform light-duty work.
The proposed restriction of portable limited class equipment to
compressors and welders has not been adopted in the final rule.
Although one commenter did support this restriction, most commenters
were opposed to it, stating that it was arbitrary and unjustified as
well as impractical. One commenter stated that the proposed restriction
would require major replacement of diesel-powered portable equipment,
either by electric-powered machines or by diesel equipment furnished
with power packages. Other commenters suggested that attended diesel
generators be added to the limited class because they presented safety
concerns that were no greater than for welders and compressors.
In response to these comments, any type of attended portable
diesel-powered equipment may be light-duty under the final rule, so
long as it does not perform any of the functions listed in paragraph
(a). As discussed more fully above, the distinction between light-duty
and heavy-duty equipment has less significance under the final rule
than it would have had under the proposal, since neither light-duty nor
heavy-duty nonpermissible equipment will be required to have a surface
temperature-controlled power package or be subject to fully assembled
machine approval.
One commenter suggested that the term ``attended'' be defined in
the final rule, and paragraph (c) specifies that attended diesel-
powered equipment for purposes of subpart T includes: any machine or
device that is operated by a miner; and any machine or device that is
mounted in the direct line of sight of a job site located within 500
feet of such machine or device, which job site is occupied by a miner.
This definition of ``attended'' is largely derived from the
definition of ``attended'' in existing Sec. 75.1107-1 applicable to
electric-powered equipment, although it has been tailored to address
safety concerns unique to diesel-powered equipment, such as the fact
that fires on diesel-powered equipment, unlike fires on electrical
equipment, do not smolder for a very long time and therefore are less
likely to be discovered before flaming and spreading. For this reason
and unlike equipment under Sec. 75.1107-1, attended equipment under
paragraph (c) must be continuously attended while it is operating,
regardless of whether it is during a production shift. Also unlike
equipment under Sec. 75.1107-1, attended equipment under paragraph (c)
does not need to be attended by the person assigned to operate it. The
definition of ``attended'' in this section permits prompt operator
action in the event of a fault or fire on a diesel-powered machine. As
discussed elsewhere in this preamble, the category of ``stationary
unattended'' equipment has not been adopted in the final rule, and
under Sec. 75.1916(e) all diesel-powered equipment must be attended
when operated.
Paragraph (d) establishes a special equipment category for diesel-
powered ambulances and fire fighting equipment, which may be used
underground only in accordance with the fire fighting and evacuation
plan required under existing Sec. 75.1101-23. This special category was
included in the proposal under Sec. 75.1907(b), but has been included
in this section of the final rule with the other categories of
nonpermissible equipment. Equipment that falls into this category is
not required to have an approved engine or power package, or to comply
with the requirements of Secs. 75.1909 and 75.1910. Instead, such
equipment must be used in accordance with the fire fighting and
evacuation plan required under existing Sec. 75.1101-23.
This provision was addressed by only a few commenters, who
supported the establishment of a special class of diesel-powered
equipment for emergency use, and has been adopted essentially unchanged
from the proposal. The equipment under this paragraph may be used only
during emergencies and the fire drills specified in the fire-fighting
and evacuation plan. Very little equipment that is currently in use
falls into this category. Mines that do have such equipment must
provide MSHA with revised fire fighting and evacuation plans that
adequately address the use of this equipment.
Sections 75.1909 and 1910 Design and Performance Requirements for
Nonpermissible Diesel-Powered Equipment
Overview. Sections 75.1909 and 75.1910 of the final rule set forth
the design and performance requirements that apply to nonpermissible
diesel-powered equipment, except for the special category of emergency
equipment established under Sec. 75.1908(d) of the final rule. Section
75.1909 requires, among other things, nonpermissible diesel-powered
equipment to be provided with engines approved under subpart F of part
7, fire suppression systems, fuel systems, and brakes. For ease of
reference, electrical system requirements, which were proposed under
Sec. 75.1909, have been adopted in the final rule in Sec. 75.1910.
As explained in greater detail in the preamble discussion for
Sec. 75.1908 of the final rule, the proposal would have established a
``limited class'' of light-duty equipment, which, although required to
have an approved engine, was not otherwise subject to MSHA approval.
Instead, limited class equipment would have been governed by the design
and performance requirements set forth in proposed
[[Page 55462]]
Sec. 75.1909. This scheme was consistent with the recommendations of
the Diesel Advisory Committee. Nonpermissible equipment that did not
meet the criteria of the limited class would have been subject to fully
assembled machine approval under subpart I of part 7, and would also
have been required to be equipped with a power package approved under
subpart G of part 7. Power packages provide the equipment with safety
features such as surface temperature controls, exhaust temperature
controls, and safety shutdown capability.
Although the proposal anticipated fully assembled machine approval
of both permissible and nonpermissible diesel-powered equipment, MSHA
specifically solicited comments on whether nonpermissible diesel-
powered equipment should be approved by MSHA in an advance notice of
proposed rulemaking published on the same day as the proposed rule.
Many commenters to the proposal and to the advance notice were strongly
opposed to fully assembled machine approval for nonpermissible
equipment, stating that it was neither necessary for safety nor
consistent with MSHA's approach to electrical equipment. These
commenters stated that approval of nonpermissible diesel equipment
would create significant technical hurdles and place unnecessary
financial burdens on mine operators, without any justification from a
safety perspective. These commenters recommended that the final rule
set performance-oriented safety requirements for nonpermissible
equipment in mandatory standards in part 75, and that the safety
features that were proposed for the limited class of light-duty
equipment in Sec. 75.1909 be applied to all nonpermissible equipment.
Many commenters were also opposed to the proposed requirement that
most nonpermissible equipment have a power package approved under
subpart F or G of part 7. Commenters stated that the protections
afforded by a power package were unnecessary for equipment operated in
areas of the mine where methane is not likely to accumulate, and that
much of the nonpermissible diesel-powered equipment currently in use
would have to be either scrapped or significantly retrofitted to comply
with the proposed requirements, at tremendous expense. Several
commenters pointed out that it would be impossible to retrofit some
types of equipment because of design limitations.
Other commenters supported full machine approval and power packages
for all nonpermissible equipment, and further recommended that all
diesel-powered equipment in underground mines be permissible and
equipped with the explosion-proof equipment features required in areas
of the mine where coal is extracted and where higher methane levels are
a concern.
The final rule responds to commenters opposed to full machine
approval for nonpermissible equipment, and does not adopt the proposed
requirement for power packages on most nonpermissible equipment. It
should be noted, however, that all nonpermissible equipment, with the
exception of emergency equipment under Sec. 75.1908(d), is required to
have an engine approved under subpart E of part 7.
In evaluating whether an approval program for nonpermissible
diesel-powered equipment was warranted in the final rule, MSHA
considered whether the machine safety features set forth in proposed
Sec. 75.1909 for the limited class of light-duty equipment could be
modified to provide adequate protection for heavy-duty equipment. This
review revealed that many requirements in proposed Sec. 75.1909 could
be applied directly to heavy-duty equipment without revision, while
other proposed requirements could be made suitable with slight
revisions.
The safety features proposed in Sec. 75.1909 for limited class
equipment have been adopted in the final rule in Secs. 75.1909 and
75.1910 to cover equipment that is larger and more powerful than what
would have been covered under the proposed rule. This is in response to
a number of commenters who believed that these proposed requirements
should be applied to both heavy-duty and light-duty equipment, in lieu
of a full machine approval program. In general, the proposed
requirements have not been substantially changed in the final rule,
although the final rule does adopt several additional requirements for
heavy-duty equipment based on requirements in part 36 or developed from
existing part 75 requirements applicable to electric-powered machines.
Other additions or revisions have been made in response to comments
received on proposed Sec. 75.1909 and in response to the advance notice
of proposed rulemaking.
Section 75.1909 Nonpermissible Diesel-Powered Equipment--Design and
Performance Requirements
Section 75.1909 establishes design and performance requirements for
diesel-powered equipment used where nonpermissible electric equipment
is permitted, with the exception of the special category of equipment
under Sec. 75.1908(d). The requirements of this section are consistent
with the recommendation of the Advisory Committee that such equipment
be provided with fire suppression system and fuel and electrical system
protection. All nonpermissible equipment, with the exception of the
special category of emergency equipment under Sec. 75.1908(d), is also
required to be provided with an approved engine within the time frames
established in Sec. 75.1907 of the final rule.
Paragraph (a)(1), like the proposal, requires that nonpermissible
diesel-powered equipment be equipped with an engine approved under
subpart E of part 7. The final rule also requires that the engine be
equipped with an air filter and an air filter service indicator. The
air filter must be sized and the service indicator set in accordance
with the engine manufacturer's recommendations.
Some commenters stated that approved engines were not necessary on
outby equipment. Other commenters recommended that all equipment used
in outby areas be provided not only with an approved engine, but also
with a permissible power package approved under subpart F of part 7.
The final rule adopts the proposed requirement that nonpermissible
equipment be provided with an approved engine. Engines approved under
subpart E of part 7 must meet specific gaseous emission standards and
be provided with an approval plate indicating the quantity of
ventilating air needed to dilute gaseous contaminants to acceptable
levels. These requirements not only place limits on the quantity of
gaseous contaminants that an approved engine may produce, they also
provide a scheme for control of those contaminants through effective
ventilation. Commenters expressed serious concern over unhealthful
exhaust emissions from diesel equipment in outby areas that may
significantly affect the quality of air that miners breathe. In
response to these concerns, the final rule takes a comprehensive
approach in addressing health hazards presented by diesel exhaust, and
requires clean-burning engines, approved by MSHA under subpart E of
part 7, on all diesel-powered machines, including nonpermissible
equipment. Engines installed in this equipment must therefore meet the
emissions standards established in subpart E of part 7.
The final rule does not adopt the suggestion of commenters who
supported requiring all diesel equipment in underground coal mines
[[Page 55463]]
to be permissible. The explosion- proof features provided by a subpart
F power package are not needed for outby equipment, because the
equipment operates in areas of the mine where methane is not expected
to accumulate. Electrical equipment without explosion-proof features
has been operated safely in outby locations for many years.
The requirement that the engine be equipped with an air filter and
an air filter service indicator has been added in response to
commenters'' statements that clogged air filters were the single most
frequent cause of smoky engines, resulting in the production of
disproportionate quantities of carbon monoxide and diesel particulate.
These components are typically supplied as part of the equipment, and
the air filter service indicator will enable the equipment operator and
maintenance personnel to ensure that the air filter is in good
condition. Both the size of the air filter and the setting of the air
filter service indicator are best determined by the engine
manufacturer, and the final rule requires that these be determined in
accordance with the engine manufacturer's recommendations.
Paragraph (a)(2) has been added to the final rule and requires that
nonpermissible equipment be provided with at least one portable
multipurpose dry chemical type (ABC) fire extinguisher, listed or
approved by a nationally recognized independent testing laboratory, and
having a 10A:60B:C or higher rating. The extinguisher must be located
within easy reach of the equipment operator and be protected from
damage. This requirement has been added to the final rule in response
to a commenter who supported requiring two chemical fire extinguishers
accessible to each end of the unit and protected from external damage.
MSHA agrees with this recommendation, which is consistent with good
fire prevention practices and which will provide additional fire
protection on diesel-powered machines. One rather than two fire
extinguishers has been required, however, because one extinguisher,
accessible to the operator and protected from damage, is adequate for
virtually all diesel-powered equipment. As discussed elsewhere in the
preamble, this equipment is also required to be equipped with either an
automatic or manual fire suppression system, depending on the equipment
category.
Paragraph (a)(3) has been adopted from the proposal, and requires
that the equipment's fuel system be specifically designed for diesel
fuel, and that it meet specific additional criteria. One commenter
recommended that this provision be revised to require a fuel system
``specifically designed and constructed to minimize the possibility of
a fire in case of a collision or refueling''. The commenter stated that
fuel tanks on most light-duty equipment, such as pickup trucks, already
meet certain standards, and that it would be unwise from a safety
standpoint to modify these tanks. The final rule has not been revised
in response to this comment. The fuel system requirements in the final
rule are designed to address safety hazards presented by the use of
diesel equipment in the underground mine environment, and nonspecific
concerns about retrofitting equipment do not outweigh the protections
afforded by the fuel system criteria included in the final rule.
However, a fuel system that meets applicable industry standards would
be acceptable so long as it also meets the criteria in paragraphs
(a)(3)(i) through (xi).
Paragraph (a)(3)(i) provides that the fuel system must have a fuel
tank and fuel lines that do not leak. The proposed rule, unlike the
final rule, would have required that the fuel tank be of ``leakproof
construction.'' Several commenters stated that the term ``leakproof
construction'' was ambiguous and needed to be defined in the final
rule, or be revised to provide for construction that was ``designed to
prevent leaks''. Rather than providing a definition for ``leakproof
construction'' and specifying design or construction requirements to
protect against leakage, the final rule sets a performance standard and
simply requires that the fuel tank and fuel lines not leak, allowing
mine operators the flexibility to determine how to best comply with
this requirement. Fuel lines have been included in this requirement
under the final rule, in response to commenters who were concerned
about fire hazards presented by leaking fuel lines on diesel-powered
equipment coming into contact with hot engine surfaces.
Paragraph (a)(3)(ii) adopts the proposed requirement that the fuel
tank be substantially constructed and protected against damage by
collision. Commenters generally supported this requirement. The tank
may be protected from damage by collision by being located within the
frame components of the machine, or be constructed of material that is
sufficiently sturdy so that the tank will not be damaged by collision
with other vehicles or with the mine roof, rib, or floor. It should be
noted that although the term ``tank'' is used in the singular here and
in other paragraphs of this section, the final rule is not intended to
limit the number of tanks on equipment. Several models of pickup trucks
are manufactured with dual fuel tanks, and this configuration is
acceptable under the final rule.
Paragraph (a)(3)(iii) requires that the fuel system be provided
with a vent opening that maintains atmospheric pressure in the tank,
and which is designed to prevent fuel from splashing out. The proposed
rule would have required that the size of the vent prevent fuel from
splashing out of the vent opening. This requirement has been modified
slightly in the final rule to specify that the design rather than the
size of the vent opening must prevent fuel from splashing out, in
response to commenters who advocated requirements that were more
performance-oriented. This minor revision will allow mine operators
increased flexibility in satisfying this requirement. MSHA anticipates
that the vent provided in the fuel filler cap will satisfy this
requirement.
Paragraph (a)(3)(iv) requires a self-closing filler cap on the
fuel tank. The proposed rule would have required either a tethered cap
or a self-closing cap. The final rule requires a self-closing fuel cap
that will serve to minimize fuel spillage, and responds to commenters''
serious concerns about the hazards of fuel spillage.
Paragraph (a)(3)(v) requires that the fuel tank, filler and vent be
located so that any leaks or spillage during refueling will not contact
hot surfaces. This requirement has been revised from the proposed rule,
which would have required that these components be located to prevent
fuel from contacting hot engine surfaces. The final rule has been
revised from the proposal because of the application of the
requirements of this section to all nonpermissible diesel-powered
equipment, not just equipment falling in the proposed limited class.
This modification recognizes that there are additional machine
components, particularly on larger heavy-duty equipment, now falling
under this requirement that reach temperatures that could ignite diesel
fuel. For example, brake components can reach temperatures that are as
high as engine temperatures.
Paragraph (a)(3)(vi) requires that fuel line piping be either:
steel-wire reinforced; synthetic elastomer-covered hose suitable for
use with diesel fuel that has been tested and has been determined to be
fire-resistant by the manufacturer; or metal. The proposal would have
required metal fuel line piping. Several commenters stated that
requiring fuel line piping to be made of metal was too restrictive.
Several of these commenters stated that metal fuel
[[Page 55464]]
lines could deteriorate over time as a result of machine vibration, and
that there were fuel lines made of other materials that were superior
in strength and performance to metal lines. The final rule has been
revised from the proposal to address these concerns. Synthetic
elastomer-covered hose must be of a type that is suitable for use with
diesel fuel, and must have been tested and determined to be fire-
resistant by the manufacturer, using any one of a number of fire-
resistance tests. Such tests have been developed by a number of
organizations, including Underwriters Laboratories, The Society of
Automotive Engineers, and the U.S. Coast Guard. MSHA's tests for flame-
resistance specified in regulations at part 18 would also be
appropriate. This will ensure that material used for diesel fuel lines
will have adequate fire-resistance in the underground coal mine
environment.
Paragraph (a)(3)(vii) adopts the proposed requirement that fuel
line piping be clamped. One commenter stated that this requirement,
along with the requirement that primary fuel lines be located so that
fuel line leaks do not contact hot surfaces, would limit machine design
flexibility. This commenter recommended that these requirements be
revised to provide that the manufacturer's design provide maximum
protection from damage. The final rule does not adopt this suggestion.
The requirements identified by the commenter are intended to address
potential hazards on diesel equipment, particularly fire hazards. The
fact that there may be some resulting limitations on machine design,
alone, does not warrant the elimination of requirements that address
specific hazards.
Paragraph (a)(3)(viii), like the proposal, requires primary fuel
lines to be located such that leaks do not contact hot surfaces. The
fuel lines referred to in this paragraph are the supply and return
lines connecting the fuel tank to the engine, not those lines that are
integral to the engine and installed by the engine manufacturer, such
as the lines connecting the injector pump to the injectors. Several
commenters supported this requirement, pointing to the potential for
fire resulting from leaking fuel dripping on hot exhaust components.
One commenter recommended that the engine be designed to shut down in
the event of a leaking fuel line. This comment has not been adopted in
the final rule, in part because MSHA is unaware of any existing
technology that would provide such a function. Additionally, such a
requirement is not necessary, given the fuel system design criteria
under this section in conjunction with the weekly equipment inspections
required by Sec. 75.1914 of the final rule. These requirements together
adequately address the potential hazard created by leaking fuel lines.
Paragraph (a)(3)(ix) requires fuel lines to be separated from
electrical wiring and protected from damage in ordinary use. This
requirement has been adopted from the proposal, and was supported by
several commenters, who mentioned incidents where fuel lines were
exposed to damage. Separation of fuel and electrical lines can
generally be easily accomplished. On machines where both electrical
lines and fuel lines are routed through a machine articulation joint,
fuel lines must be bundled separately from electrical lines and must be
positioned so that fuel leaks will not contact electrical lines.
Paragraph (a)(3)(x) requires that a manual shutoff valve be
installed in the fuel system as close as practicable to the tank. The
language of the final rule has been modified from the proposal, which
would have required the valve to be located ``near'' the tank. This
change is made in response to a commenter who stated that valves
located ``near'' the tank would not necessarily be easily accessible to
the equipment operator or other mine personnel when the fuel supply
needs to be shut off in an emergency or for maintenance. The commenter
recommended that this aspect of the proposal be revised to require
shutoff valves as close as practicable to the tank, and the final rule
adopts this comment.
Paragraph (a)(3)(xi) adopts the proposed requirement that equipment
be provided with fuel filter(s) and a water separator. The final rule
substitutes the term ``water separator'' for the term ``water
strainer'' used in the proposal. The terms mean the same thing, but
``water separator'' is more commonly used and more widely understood.
Although commenters generally supported this requirement, one commenter
stated this requirement should be eliminated because fuel filters and
water separators were not necessary. MSHA disagrees with this
commenter, and the proposed requirement has been included in the final
rule. Fuel filters filter out particulate matter in fuel, thereby
reducing diesel exhaust emissions as well as slowing engine wear. Water
separators filter out water in the fuel, and minimize fuel system
corrosion. Several commenters recommended that the proposed requirement
be revised to permit the use of a single device that functions as both
a fuel filter and a water separator. Such combination devices will
satisfy the requirements of this section. The final rule has not been
revised, however, because the language as proposed and as adopted in
the final rule does not preclude the use of a combination fuel filter/
water separator.
The proposed requirement for a fuel tank drain plug has not been
adopted in the final rule. Although the drain plug is usually provided
on larger mining equipment, it is typically not provided on light-duty
equipment such as pickup trucks. Although a drain plug is a convenient
feature for persons performing equipment maintenance, it is not
necessary from a strict safety standpoint. For these reasons, a fuel
tank drain plug is not required under the final rule.
Paragraph (a)(4) adopts the requirement of the proposal for a
sensor to monitor the temperature and provide a visual warning of an
overheated cylinder head on air-cooled engines. This feature is
necessary because it reduces potential fire hazards on air-cooled
engines. While such sensors do not completely eliminate the hazards of
hot surface temperatures, they do provide additional protection by
warning the equipment operator of overheating. The proposed rule would
have required a temperature sensor to be located in the engine
compartment that would automatically activate an intake air shutdown
device to stop the engine before the engine compartment temperature
exceeded the actuation temperature of the fire suppression system. This
requirement has not been adopted in the final rule. Although commenters
generally supported the concept behind this requirement, they had
varied concerns about its application and impracticality from a
technological standpoint. One commenter stated that this requirement
could create a safety hazard because the engine could be shut off
unexpectedly. Since loss of steering and braking could result, this
commenter recommended that the engine be shut off only upon actuation
of the fire suppression system. Several commenters stated that use of
manual fire suppression systems on equipment was incompatible with this
requirement.
MSHA agrees that this proposed requirement could have resulted in
the equipment losing control of the machine in the case of unexpected
engine shutdown, and the engine should only be shut down upon actuation
of the fire suppression system. The automatic engine shutdown under the
proposal would have been triggered before the engine temperature
exceeded the actuation temperature of the fire suppression system.
Section 75.1911(d)
[[Page 55465]]
of the final rule already requires fire suppression systems for diesel-
powered equipment to provide for automatic engine shutdown, and a
redundant requirement for automatic engine shutdown at a lower
temperature is not necessary. An increase in the engine compartment
temperature may reflect an engine malfunction, such as loss of engine
coolant, but does not necessarily indicate a safety hazard. Linking
engine shutdown to the engine compartment temperature would have
provided protection against engine damage rather than addressing a
discrete safety hazard. Equipment manufacturers routinely provide
gauges in the equipment operator's compartment that indicate engine
faults. Equipment operators will be alerted by this warning system and
will then be able to shut the engine down, if appropriate. For these
reasons, the proposed requirement for automatic engine shutdown based
on engine compartment temperature has not been adopted in the final
rule.
Paragraph (a)(5) requires that guarding be provided to protect
fuel, hydraulic, and electric lines when such lines pass near rotating
parts and to protect the lines in the event of shaft failure. This
requirement is intended to prevent leaks and short circuits caused by
fuel, hydraulic, and electric lines abrading against rotating parts.
Rotating parts include machine components such as pulleys, belts, fans,
and shafts. This requirement is similar to that of the proposal,
although the proposed rule had specified that ``adequate guarding'' be
provided and did not include protection for hydraulic lines or
protection in case of shaft failure. The word ``adequate'' is redundant
in this context and has not been adopted in the final rule. The
reference to ``hydraulic lines'' was not included in the proposal
because no hydraulic systems were permitted on the limited class of
equipment for which the requirement was proposed. Under the final rule
these requirements apply to larger equipment with hydraulic systems,
and protection for hydraulic lines has therefore been added. Guarding
to protect against shaft failure has also been added to the final rule
to address the design features of the larger equipment now governed by
these requirements. MSHA has received reports of several fires ignited
by broken shafts that damaged hydraulic and electrical lines.
One commenter supported this requirement, while another commenter
believed that it was unnecessary. A third commenter recommended that
the engine compartment be shielded by metal from hydraulic components.
Protection for fuel, hydraulic, and electrical lines is an essential
element in preventing fires. The final rule does not specify what
method must be used to comply with this requirement, because a number
of different methods, including guarding, shielding as recommended by
the commenter, or relocation of fuel, hydraulic or electrical lines,
can provide adequate protection.
Paragraph (a)(6) has been added to the final rule and requires that
hydraulic tanks, fillers, vents, and lines be located so that any
spillage or leaks will not contact hot surfaces. This requirement has
been added to the final rule to supplement the guarding of hydraulic
lines in paragraph (a)(5) and is supported by the Ontario fire accident
data, which show that leaking hydraulic lines contribute to fires. This
requirement was not included in the proposal because, as explained in
the discussion of paragraph (a)(5), hydraulic systems would not have
been permitted on the limited class of light-duty equipment to which
the requirement would have applied under the proposal. This requirement
will ensure that spills and leaks of combustible hydraulic fluid do not
contact hot equipment surfaces. This requirement can be satisfied by
relocation of machine components, or by directing spills and leaks away
from hot surfaces by means of splash guards or other such devices.
Paragraph (a)(7) requires that reflectors or warning lights which
can be readily seen in all directions be mounted on equipment. This
requirement was generally supported by commenters and is adopted
unchanged from the proposal. A determination of whether the reflectors
or warning lights can be ``readily seen'' must be based on the unique
mine conditions, and must take into account such things as equipment
size in relation to the mine entry and undulating mine terrain.
Paragraph (a)(8) has been added to the final rule in response to
comments, and requires that a means be installed on the equipment to
direct exhaust gas away from the equipment operator and persons on
board the machine. This requirement is intended to provide for the
discharge of exhaust gases away from persons on the machine to the
greatest extent practicable, minimizing their exposure to excessive
levels of unhealthful diesel exhaust contaminants. The exhaust pipe
must direct the flow away from any area where a machine operator or a
passenger could be located. Exhaust pipes that extend straight up and
that would allow the exhaust to flow back over the equipment operator
as the machine moves forward, such as on some agricultural and
commercial equipment, are unacceptable under the final rule. This
requirement is added to the final rule in response to the
recommendation of two commenters, one of whom noted that exhaust gases
can build up in the operator's compartment of a machine.
Paragraph (a)(9) has been added to the final rule in response to a
commenter and as a result of the expansion of the class of equipment
subject to the requirements of this section. This paragraph requires
that a means be provided to prevent unintentional free and uncontrolled
descent of personnel-elevating work platforms. Personnel-elevating work
platforms normally are equipped with hydraulic systems and would
consequently not have been eligible for inclusion in the category of
limited class equipment under the proposed rule. This requirement is
currently applied to equipment approved under existing part 36.
Hydraulically operated personnel-elevating platforms meeting the
applicable American National Standards Institute criteria for
personnel-elevating platforms (i.e., ANSI A92.2 and A.92.5) would be
acceptable. This requirement also applies to work platforms which
utilize other methods to raise the platform, such as wire ropes. The
machine must be provided with a specific feature that prevents the free
and uncontrolled descent of the platform in the event of a failure in
the lifting system, such as a ruptured hydraulic hose or broken wire
rope. In such a situation, the platform must descend at a rate which
will not endanger miners located on or below the platform.
Paragraph (a)(10) has been added to the final rule and requires
that all nonpermissible equipment be provided with a means to prevent
the spray from ruptured hydraulic or lubricating oil lines from being
ignited by contact with engine exhaust system component surfaces. This
requirement achieves the goal of the limitation of surface temperatures
in proposed subpart G of part 7, which is not adopted in the final
rule, and recognizes that high surface temperatures on diesel-powered
equipment can be controlled in ways other than the water-jacketing of
hot engine components contemplated under proposed subpart G. The
requirement of this paragraph, in conjunction with other requirements
in the final rule for control of fuel sources on diesel-powered
machines, will provide effective fire prevention on nonpermissible
diesel-powered equipment used underground.
The requirements of this paragraph are performance-oriented, and
are
[[Page 55466]]
intended not only to allow flexibility in compliance but also to
accommodate new technology developed in the future. One method of
achieving compliance with this requirement is through the use of a
water-cooled manifold. A safety component system certified under part
36 or a power package approved under subpart F of part 7 of the final
rule also satisfies the requirement of this paragraph.
Non-absorbent insulating materials are also available for use on
mining equipment to reduce the surface temperature of diesel exhaust
system components. Such materials, which were first developed for
diesel-powered military vehicles, are impervious to hydraulic fluid,
lubricating fluids, and diesel fuel, and have been successfully used on
mining equipment in the United States and Canada. Use of these
materials can reduce surface temperatures of exhaust components to less
than 300 deg.F, and may also be used to prevent contact of hydraulic
fluid and lubricating oil with hot surfaces. The goal of applying the
insulating material is to substantially reduce the surface area of the
exhaust system that is at elevated temperatures, because of the direct
relationship between the area of a hot surface and the likelihood of
ignition of a spray of hydraulic fluid. A large area of exhaust
component, which includes the turbocharger, at a high temperature is
more likely to ignite a spray.
The use of shielding or partitions to isolate hydraulic components
from the engine would also satisfy the requirement of this paragraph,
preventing the fluid from contacting the engine in the event of a leak.
One commenter retrofitted a diesel-powered machine to provide shielding
of the engine.
Paragraph (b) sets forth additional requirements for self-propelled
nonpermissible diesel-powered equipment, which are specifically
designed for equipment that moves under its own power, as opposed to
equipment that is towed. Paragraph (b)(1) has been added to the final
rule and requires a means to ensure that no stored hydraulic energy
that will cause machine articulation is available after the engine is
shut down. As discussed elsewhere in the preamble, requirements
relating to hydraulic systems were not included in the proposal because
the affected equipment could not have hydraulic systems. This
requirement is intended to eliminate accidents where an equipment
operator inadvertently activates the steering controls on articulated
vehicles when entering or exiting the operator's compartment. In many
articulated machine designs, personnel must enter the equipment
operator's compartment through the articulation area. If the
articulation joint were to close as the operator entered the
compartment, the operator could be crushed. This requirement will also
protect miners who encounter a machine that has been shut down and who
may accidentally activate the control levers. Under the final rule, the
stored hydraulic energy does not have to be dissipated instantly. The
time permitted for dissipation of the stored energy will depend on the
machine design and the amount of movement the machine is capable of
after shutdown.
Paragraph (b)(2) has been added to the final rule in response to a
specific comment that equipment should only be able to start in
neutral. This paragraph requires equipment to be provided with a
neutral start feature which ensures that engine cranking torque will
not be transmitted through the powertrain and cause machine movement on
vehicles utilizing fluid power transmissions. MSHA agrees with the
commenter that this requirement is necessary, because some types of
diesel-powered equipment may be started with the transmission in gear.
This could result in power being delivered to the driving wheels of the
machine before the equipment operator is in control of the vehicle,
endangering both the operator and miners working in the vicinity of the
equipment. Equipment must be designed such that its transmission is in
either neutral or park before the starter will crank the engine.
For machines with steering wheels, brake pedals, and accelerator
pedals, paragraph (b)(3) requires that the controls be arranged
consistent with standard automobile orientation. This requirement has
been added in response to a commenter who was concerned that equipment
operators could become confused in the operation of equipment controls.
Under this paragraph the brake pedal must be on the left and the
accelerator must be on the right when the operator is facing the
controls. Clockwise rotation of the steering wheel must turn the
machine to the right, and counter-clockwise rotation of the steering
wheel must turn the machine to the left. For machines with seating
perpendicular to the direction of travel, the forward direction of
travel and the automobile orientation of the controls are to be defined
with respect to the front end of the equipment. For machines where the
operator changes seats depending on the direction of travel, the
machine control movements should also change accordingly, to retain the
automobile orientation.
Paragraph (b)(4), like the proposal, requires self-propelled
equipment to be provided with an audible warning device conveniently
located near the operator. Such a device could be a horn or bell, and
must be capable of being heard over the operation of the machine by
miners in the area. Commenters were generally supportive of this
provision.
Paragraph (b)(5) requires that lights be provided and maintained on
both ends of the equipment. Equipment normally operated in both
directions must be equipped with headlights for both directions. The
proposal would have required self-propelled equipment to be provided
with headlights, tail lights, and back-up lights. The requirement in
the final rule is derived from the proposal but has been revised to
better address typical lighting configurations on all types of
nonpermissible equipment, not only the limited class of equipment that
would have been affected under the proposal. For equipment such as
ramcars, headlights on each end of the machine would be required, but
not tail lights or back-up lights. For pickup trucks, headlights and
back-up lights installed as original equipment would satisfy this
requirement. The lights required by this paragraph are in addition to
the warning lights or reflectors required by paragraph (a)(7) of this
section.
Under the proposal lights would have been required to be
``protected from accidental damage''. The final rule requires instead
that lights be ``maintained'', in response to a commenter who
questioned what was meant by ``protected from accidental damage.''
Under the final rule equipment lights must be kept in working order,
and replaced if they burn out or are damaged.
Although most commenters generally agreed with the proposed
requirement, one commenter supported a requirement for back-up alarms
or other means to alert miners to a change in the direction that
equipment is moving. Although a back-up alarm may be appropriate on
some equipment, an alarm on equipment that normally operates in both
directions is not advisable because the alarm would be set off on a
regular basis, defeating its effectiveness as a warning system. This
suggestion has therefore not been adopted in the final rule.
Paragraph (b)(5) also requires equipment that normally operates in
both directions to be equipped with headlights for both directions. One
commenter recommended that lights be designed for operation in both
[[Page 55467]]
directions at once. This commenter noted that normally the light switch
allows the lights to be on in only one direction and that it would be
beneficial to observe the load while traveling in the other direction.
Although this feature may be appropriate under some circumstances, it
would provide no significant safety benefit and is not warranted for
inclusion as a general machine feature. In many mines, the fact that
lights are illuminated in only one direction at a time allows other
miners in the vicinity to determine the equipment's direction of
movement and provides some safety benefit. Illumination of both sets of
lights at the same time would eliminate this capability, and this
suggestion has therefore not been adopted in the final rule.
Paragraph (b)(6) requires that self-propelled nonpermissible
equipment be provided with service brakes that act on each wheel of the
vehicle and that are designed such that failure of any single
component, except the brake pedal or similar actuation device, does not
result in a complete loss of service braking capability. This paragraph
requires two separate brake systems and ensures that, in the event of
the failure of one braking system, the other system can bring the
machine to a controlled stop. The only common component permitted in
the two systems is the brake pedal or a similar device, such as a lever
or button that is actuated by the equipment operator. This requirement
has been adopted from the proposal with slight revisions to specify
that the service brakes ``act on each wheel'' instead of ``for each
wheel''. This will allow the use of axle brakes, which act on all of
the wheels on that axle. This requirement prohibits drive line brakes
in which failure of a single drive shaft or chain results in the loss
of all braking capability. A split brake system with two completely
independent hydraulic circuits with an automotive-type dual piston
master cylinder complies with this requirement.
The proposal provided that failure of one ``brake line'' must not
result in a complete loss of service braking capability. This language
has been changed to provide that failure of any ``single component''
must not result in a complete loss of service braking capability, to
conform the requirement to the expanded range of equipment that is
governed by this requirement under the final rule.
The brake pedal or other interface between the equipment operator
and the braking system is excluded from this requirement. If the pedal
is connected to more than one link to activate the brake systems, those
links must provide for independent actuation of the brake systems in
the event of the failure of one of the links. Drive line brakes are not
adequate because of the frequent failure of universal joints. The
failure of the universal joint could result in the loss of all braking
ability if a second brake system is not provided. Most agricultural
equipment and some commercial equipment used in mines, such as high
lifts or backhoes, may need a retrofit of their braking systems to
comply with this requirement.
Several commenters supported this requirement and recommended two
braking systems independent of each other in all working aspects. Other
commenters noted that a single brake system would be adequate for
tractor-type vehicles because they travel at speeds of less than 15
mph. MSHA disagrees that the low speeds of this type of equipment
eliminates the need for two brake systems. Failure of an equipment's
brake system in the confined area of an underground coal mine could
result in serious injury or death, even at speeds of 15 mph or less.
The final rule therefore does not incorporate this comment. Other
commenters were of the opinion that the brake systems should not be
separate for each wheel. This recommendation has been incorporated into
the language of the final rule.
Paragraph (b)(7) has been adopted unchanged from the proposal and
requires self-propelled nonpermissible equipment to be provided with
service brakes that can safely bring the fully loaded vehicle to a
complete stop on the maximum grade on which it is operated. No stopping
distance or braking force is specified in the final rule, to allow
flexibility in equipment design and usage. Compliance with this
requirement is highly site-dependent because of the variation in mine
grades. The mine operator is responsible for ensuring that equipment
with adequate grade-holding ability is used at a particular location.
Commenters generally supported this requirement.
Paragraph (b)(8) has been added to the final rule and requires that
no device that traps a column of fluid to hold the brake in the applied
position be installed in any brake system, unless the trapped column of
fluid is released when the operator is no longer in contact with the
brake activation device. This requirement prohibits the installation of
``park'' brakes devices which rely on a trapped column of fluid, and
has been included in response to the suggestion of commenters. The use
of such devices can present serious hazards, and are prohibited.
Because the temperature of hydraulic brake fluid increases due to
usage, a column of fluid trapped at a sufficient pressure will
initially apply the brakes sufficiently to hold the machine stationary.
However, as the fluid cools it contracts, lowering the pressure and
possibly releasing the brakes. These devices are not permitted even as
supplemental devices, because of the risk that equipment operators
would use them as park brakes even if another park brake is provided.
Several fatal accidents have been attributed to use of these devices,
also called ``mico lock braking systems''.
This requirement does not apply to normal automotive-type service
brakes which trap a column of fluid, as long as the operator is
applying pressure to the foot pedal. This requirement also does not
preclude the use of hydrostatic drive wheel motors that are designed
and maintained to function as service brakes. These wheel motors do not
necessarily lose their service braking ability if the fluid cools or if
minimal leakage occurs. The wheel motors can act to maintain continuous
pressure in the braking circuit. Although hydrostatic wheel motors can
function as adequate service brakes, these systems do not provide
adequate parking brake capability. For the wheel motor to maintain
pressure in the braking circuit, the wheel must turn slightly, thereby
permitting the machine to move very slowly down the grade. This
movement is insignificant during the short period of time the service
brakes are applied. However, if wheel motors are used as parking
brakes, the machine can move a significant distance when the equipment
operator is away from the machine. This can endanger miners who may be
working near the machine in the confined area of the mine.
Paragraph (c) has been added to this section of the final rule to
specifically address self-propelled nonpermissible heavy-duty diesel-
powered equipment meeting the requirements of Sec. 75.1908(a), except
rail-mounted equipment. These requirements have been added to the final
rule in response to the additional types of equipment that are now
subject to the requirements of this section. Heavy-duty equipment that
hauls rock, coal, or longwall components or transports large quantities
of diesel fuel are governed by these safety requirements, and must be
provided with a supplemental braking system that meets specified
criteria. The criteria for these braking systems were developed from
the criteria contained in Sec. 75.523-3, applicable to automatic
emergency parking brakes on similar
[[Page 55468]]
types of electrical equipment. There was widespread support for
applying these braking requirements to diesel-powered equipment, in
comments submitted in response to the advance notice of proposed
rulemaking addressing equipment approval and machine safety features.
Although there was a difference of opinion among these commenters as
far as whether these braking requirements should be incorporated as
part of an equipment approval program, commenters did agree that they
be included as machine features either in an approval program or as
mandatory safety standards in part 75. Commenters also recommended that
there should be separate brake requirements for rail-mounted equipment.
The Agency agrees with these comments, and has concluded that existing
brake requirements in Secs. 75.1404 and 75.1404-1, which apply to both
electric and diesel-powered rail-mounted equipment, provide sufficient
protection. Rail-mounted equipment has therefore been specifically
excluded from this requirement under the final rule.
Existing Sec. 75.523-3 specifies different requirements for two
types of electric-powered equipment: haulage equipment and all other
equipment. Electric-powered haulage equipment is very similar in
function to the heavy-duty diesel-powered equipment subject to this
requirement. Paragraphs (c)(1) through (c)(5) of this section of the
final rule closely track the brake system requirements for electric
haulage equipment in existing Sec. 75.523-3, with the exception of the
requirement that the brake be engaged by an emergency deenergization
device or panic bar. A panic bar is appropriate for only some types of
permissible diesel-powered equipment, and will be addressed during the
part 36 approval process. Panic bars are not required for
nonpermissible diesel-powered equipment. Under the final rule, self-
propelled nonpermissible heavy-duty diesel-powered equipment, except
rail-mounted equipment, is required to have a supplemental braking
system that: (1) Engages automatically within 5 seconds of shutdown of
the engine; (2) safely brings the equipment when fully loaded to a
complete stop on the maximum grade where it is operated; (3) holds the
equipment stationary, despite any contraction of brake parts,
exhaustion of any nonmechanical source of energy, or leakage; (4)
releases only by a manual control that does not operate any equipment
function; (5) has a means in the equipment operator's compartment to
apply the brakes manually without the engine operating, and a means to
release and reengage the brakes without the engine operating; and (6)
has a means to ensure that the supplemental braking system is released
before the equipment can be trammed, and is designed to ensure that the
brake is fully released at all times when the equipment is trammed.
Paragraph (c)(6) has been added to the final rule and requires that
the supplemental braking system have a means to ensure that the system
is released before the equipment can be trammed. It further requires
that the system be designed to ensure the brake is fully released at
all times while the equipment is trammed. This requirement is added to
the final rule to address the hazard of dragging brakes, which were the
cause of numerous fires reported in the Ontario fire data analyzed by
MSHA in response to a commenter's recommendation. Some manufacturers
install a lever on the transmission gear selector to ensure that the
supplemental brakes are released. This lever automatically releases the
brake when the operator shifts the transmission into gear.
Paragraph (d) applies to self-propelled nonpermissible light-duty
diesel-powered equipment meeting the requirements of Sec. 75.1908(b),
except rail-mounted equipment. This provision, which has been adopted
from the proposal, requires that the equipment be provided with a
parking brake that holds the fully loaded equipment stationary on the
maximum grade on which it is operated despite any contraction of the
brake parts, exhaustion of any nonmechanical source of energy or
leakage. This requirement was developed from existing Sec. 75.523-3(d),
which addresses parking brakes for electric-powered equipment other
than haulage equipment, which is similar to the equipment in the light-
duty category under Sec. 75.1908(b) of the final rule.
A parking brake meeting the requirements of paragraph (d), rather
than the supplemental brake system required for heavy-duty equipment
under paragraph (c), is adequate for light-duty equipment, which is
typically used for transportation or moving of supplies on an
intermittent basis.
Paragraph (e) has been added to the final rule as a result of the
inclusion of requirements for supplemental and park brake systems under
paragraphs (c) and (d) of this section. This paragraph requires that
the supplemental and park brake systems required by paragraphs (c) and
(d) be applied when the equipment operator is not at the controls of
the equipment, except during movement of disabled equipment. This
requirement was developed from existing Sec. 75.523-3(e), and requires
the machine operator to set the brakes when not at the controls.
However, this provision is not intended to suggest that it would be a
safe practice for the operator to apply the brake and leave the machine
with the engine running.
Paragraph (f) has been added to the final rule as a result of
MSHA's review of the Ontario fire data, and requires self-propelled
personnel-elevating work platforms be provided with a means to ensure
that the parking braking system is released before the equipment can be
trammed, and that the platforms be designed to ensure the brake is
fully released at all times while the equipment is trammed. MSHA's
review of the Ontario fire data revealed a high number of personnel-
elevating vehicle fires caused by dragging brakes. The final rule
applies the same requirement to personnel-elevating vehicles in this
paragraph as applies to self-propelled heavy-duty nonpermissible
equipment under paragraph (c)(6).
Paragraph (g) has been added to the final rule and requires that
any nonpermissible equipment that discharges its exhaust directly into
a return air course be provided with a power package approved under
subpart F of part 7. The basis for this requirement is the possibility
that the return air course may contain high levels of methane, which
could be drawn into the machine's exhaust system as it cools after
engine shutdown. This creates the potential for ignition of the methane
by the hot surfaces of the diesel engine. As a result, the final rule
requires equipment which discharges its exhaust directly into the
return to be furnished with the fire and explosion protection provided
by a subpart F power package. Equipment without a subpart F power
package must discharge its exhaust into intake air.
Under the proposed rule all nonpermissible equipment, with the
exception of a limited class of light-duty equipment, would have been
required to be equipped with a power package approved under either
subpart F or G of part 7. Subpart F power packages are equipped with
spark arresters and flame arresters, which significantly reduce the
likelihood that equipment will ignite explosive levels of methane.
Because the final rule does not require power packages on
nonpermissible equipment, this requirement has been added to the final
rule to ensure that nonpermissible equipment that discharges it exhaust
directly into a return air course, which could contain explosive levels
of
[[Page 55469]]
methane, will not create an explosion hazard.
Paragraph (h) requires that self-propelled nonpermissible heavy-
duty equipment meeting the requirements of Sec. 75.1908(a) be provided
with an automatic fire suppression system meeting the requirements of
Sec. 75.1911. Paragraph (i) requires that self-propelled nonpermissible
light-duty equipment meeting the requirements of Sec. 75.1908(b) be
provided with a manual or automatic fire suppression system meeting the
requirements of Sec. 75.1911. Under the proposed rule, all
nonpermissible equipment would have been required to be provided with
an automatic fire suppression system.
As explained in greater detail in the preamble discussion for
Sec. 75.1911 of the final rule, some commenters supported automatic
fire suppression systems for all types of equipment, while others
expressed support for automatic fire suppression systems on portable or
unattended equipment but were strongly opposed to requiring automatic
fire suppression on all types of nonpermissible diesel-powered
equipment. These commenters stated that automatic fire suppression
systems were much more difficult to maintain, and were unnecessary for
equipment that was attended by an equipment operator. These commenters
suggested that mine operators should have the option of installing
either manual or automatic systems on self-propelled equipment, stating
that the equipment operator is in the best position to detect machine
fires, and would be able to actuate a manual fire suppression system
more easily than an automatic system. Other commenters stated that it
might be difficult for an equipment operator to actuate a manual system
depending on the size and type of the fire, expressing concern that an
equipment operator could be overcome by the effects of a fire or
explosion and not be able to manually extinguish the fire.
As discussed more fully under Sec. 75.1911 of the preamble, the
Ontario fire accident data indicates that heavy-duty diesel-powered
equipment, such as the type specified in Sec. 75.1908(a) of the final
rule, presents a much greater fire hazard than light-duty equipment.
Although light-duty equipment still presents some fire risk, a
manually-actuated fire suppression system provides adequate protection
if the equipment is attended and provided with additional safety
features for protection of fuel, hydraulic, and electrical systems
under this section and Sec. 75.1910 of the final rule. As noted
elsewhere in this preamble, Sec. 75.1916(d) of the final rule requires
all diesel-powered equipment to be attended while it is being operated.
An automatic fire suppression system is needed on equipment that
presents a greater fire risk. Good fire fighting practice demands that
a fire be suppressed as early as possible, and several reports of fire
indicate that the rapid growth of a fire prevented the equipment
operator from actuating the manual fire suppression system. Automatic
systems respond quickly to fire without operator intervention, and are
needed on equipment that operates frequently for long periods of time
under high load, presenting an increased fire risk. Compressors and
other non-self-propelled equipment also operate for long periods of
time under high load. This results not only in high engine temperatures
but also increases the possibility of mechanical failure, presenting
ignition and fuel sources. To address these hazards, automatic fire
suppression systems meeting the requirements of Sec. 75.1911 of the
final rule are required under paragraph (h) for self-propelled heavy-
duty nonpermissible equipment, and under paragraph (j)(3) for both
heavy-duty and light-duty equipment that is not self- propelled.
Paragraph (i) provides that self-propelled light-duty nonpermissible
equipment may be provided with either a manual or an automatic system
that meets the requirements of Sec. 75.1911.
Paragraph (j) requires nonpermissible diesel-powered equipment that
is not self-propelled to be provided with features in addition to those
listed in paragraph (a). These features include a means to prevent
inadvertent movement of the equipment when parked, safety chains or
other suitable secondary connections on equipment that is being towed,
and, as discussed above, an automatic fire suppression system meeting
the requirements of Sec. 75.1911. A requirement for automatic fire
suppression for non-self-propelled equipment has been retained in the
final rule in recognition of the fact that non-self-propelled equipment
is typically operated under load for extended periods of time,
resulting in the need for automatic rather than manual fire suppression
to address the additional fire risks. MSHA intends that automatic fire
suppression systems be provided for those machines, such as
compressors, welders, and generators, that may have some limited
capacity for self- propulsion but which essentially function as
portable equipment, i.e., where the equipment operator performs a
function some distance from the machine while the equipment is running.
The proposal would have required a means to prevent inadvertent
movement as well as safety chains or other connections for equipment
being towed, but would have required a fire extinguisher instead of an
automatic fire suppression system. The proposal would also have
required the equipment to be provided with a sensor to monitor
equipment operation that would stop the engine when an equipment
malfunction would result in the creation of a hazard.
The proposed requirement for sensors to monitor the operation of
portable equipment has not been adopted in the final rule. Several
commenters expressed confusion as to what these devices were intended
to monitor, and suggested that this requirement be eliminated because
it was vague and ambiguous. The proposed requirement was intended to
ensure that general safety devices supplied as original equipment
features, such as low oil sensors or high temperature sensors, were
maintained in proper working condition. However, MSHA has concluded
that it would be extremely difficult to develop a standard that is any
more specific than what was proposed that would be suitable for the
variety of monitors and sensors that may be installed on equipment. In
light of these circumstances, and in light of the fact that all
equipment used in underground coal mines is required to be maintained
in safe operating condition under existing Sec. 75.1725, this
requirement has not been adopted in the final rule.
A number of commenters recommended that additional equipment safety
features be required in the final rule that were not included in the
proposal. Several commenters expressed concern about limited visibility
from the operator's compartment on certain types of large diesel-
powered equipment. The final rule does not adopt these commenters'
recommendations. Although this concern is addressed to some extent by
Sec. 75.1916 of the final rule, which requires that mines using diesel-
powered equipment establish and follow standardized traffic rules, MSHA
has concluded that the issue of operator equipment design and
visibility should be addressed in the context of all types of
equipment, not only diesel-powered equipment. Specific provisions on
operator visibility have therefore not been included in the final rule.
[[Page 55470]]
Section 75.1910 Nonpermissible Diesel-Powered Equipment; Electrical
System Design and Performance Requirements
This section addresses electrical system requirements for
nonpermissible diesel-powered equipment. These requirements were
proposed in Sec. 75.1909 with other equipment safety requirements that
would have applied to a limited class of nonpermissible light-duty
equipment, but in the final rule are included separately in
Sec. 75.1910.
Faulty equipment electrical systems have frequently been the cause
of equipment fires, and the requirements of this section address the
hazards associated with these systems. Although commenters generally
supported the proposed requirements, one commenter suggested that these
requirements not be adopted in the final rule, because some equipment
is designed for highway use and meets safety standards that have been
developed by the industry over many years. The commenter asserted that
changing the design of those machines' electrical systems would have an
adverse impact on machine safety. MSHA is aware that electrical systems
on certain types of diesel-powered equipment, such as utility vehicles,
personnel carriers, and ambulances, are designed to meet safety
standards for highway use. However, this final rule expands the scope
of the limited class of equipment to include types of equipment that
would not meet the requirements for highway use. Additionally, because
of the significant hazards presented by a fire in an underground mine,
additional safeguards for electrical systems on equipment employing
storage batteries and integral charging systems are warranted, given
the fact that a number of electrical accidents have been attributed to
faults in these systems. The analysis of the Ontario fire accident data
revealed that 43 percent of the fires were attributable to electrical
system faults. Almost half of these were related to the engine starting
and charging systems. Changes in machine design to comply with the
requirements in this section are necessary to enhance safety. For these
reasons, the final rule retains these special provisions.
The requirements included under this section of the final rule
apply only to those electrical circuits and components associated with,
or connected to, electrical systems utilizing storage batteries and
integral charging systems. It should be noted, as indicated in the rule
itself, that these requirements do not apply to equipment that falls
within the special category of emergency equipment under
Sec. 75.1908(d) of the final rule. The requirements in this section
would apply, for example, to circuits for instrument panel gages and
machine lights on most equipment utilizing storage batteries and
integral charging systems. Accordingly, electrical systems on
nonpermissible diesel-powered equipment without storage batteries and
charging systems are not governed by the requirements of this section.
Additionally, the requirements of this section do not apply to
electrical circuits and components on equipment that is not directly
connected to or otherwise powered from a separate electrical system
utilizing storage batteries and an integral charging system. Both types
of systems should be designed and maintained in compliance with
existing safety standards in part 75 for underground coal mines.
Several commenters suggested that the proposed electrical system
requirements not be adopted in the final rule, and instead that the
final rule provide that electrical systems on diesel-powered equipment
comply with existing part 75 electrical safety standards for
nonpermissible equipment. Some of these commenters also suggested that
more performance-oriented standards be developed for electrical
circuits and components associated with storage batteries and charging
systems.
Performance-oriented requirements have been adopted where
appropriate in the final rule to allow flexibility in design and to
facilitate future development of new and improved technology. Instead
of simply applying existing requirements to this equipment, as
suggested by some commenters, many of the requirements of this section
have been derived from existing MSHA electrical safety standards in
part 75 but have been tailored to apply to diesel-powered equipment.
It should be noted that MSHA does not consider the continuous on-
board recharging of the battery on this equipment, which typically
power auxiliary features such as headlights, to be the type of battery-
charging contemplated by existing Sec. 75.340.
Paragraph (a) addresses overload and short circuit protection of
electric circuits and components and, like the proposal, requires that
such protection be provided in accordance with existing Secs. 75.518
and 75.518-1. The references to the existing sections have been
retained in the final rule in response to commenters' suggestions that
such references would minimize confusion over what the standard
requires.
Paragraphs (b) and (c) are adopted from the proposal and were
developed from existing approval requirements for electrical systems on
other types of diesel-powered equipment. Paragraph (b) requires that
each electric conductor from the battery to the starting motor be
provided with short circuit protection, and requires that the short
circuit protective device be placed as near as practicable to the
battery terminals. Paragraph (c) requires that each branch circuit
conductor connected to the main circuit between the battery and the
charging generator be provided with circuit protection. When complied
with, these requirements will provide all electric conductors and
circuits with circuit protection and will minimize the hazards of fire
due to circuit failure.
Paragraph (d), like the proposal, requires that a main circuit-
interrupting device be provided in the electrical system so that power
may be disconnected from the equipment, at or near the battery
terminals, in the event of an emergency. The device must be located as
close as practicable to the battery terminals and be designed to
operate within its electrical rating without damage. This paragraph
also requires that the device not automatically reset after being
actuated, and that magnetic devices be mounted in such a manner to
preclude closing by gravity. This requirement reduces the possibility
of a fire in the event of a short circuit protective device
malfunction. The proposal would have provided that a manually operated
controller, such as a rheostat, would not be acceptable as a service
switch. This provision has not been included in the final rule because
it is redundant and adds nothing of substance to the paragraph.
Manually operated controllers are not typically used on diesel-powered
equipment, and would be prohibited in any case by the language in the
final rule.
Under the final rule circuit-interrupting devices must be designed
not to automatically reset after being actuated. If the circuit has
been interrupted it is most likely due to some fault in the system, and
an automatic reset would defeat the purpose behind the device. These
devices must also be operational within their electrical rating without
damage, because otherwise they could self-destruct. Magnetic circuit-
interrupting devices are required to be mounted in a manner that
prevents gravity from closing the contacts to prevent a premature or
undesirable activation of electric circuits. The requirements of this
paragraph ensure proper design and installation of circuit-interrupting
devices.
[[Page 55471]]
The proposed rule would have included the additional requirement
that circuit-interrupting devices and other controls be designed so
that they could be operated without opening any compartment in which
they were enclosed. This proposed provision has not been adopted in the
final rule, in response to commenters who advocated performance-
oriented requirements. The proposal would also have required that
circuit-interrupting devices meet the requirements of existing
Sec. 75.520, which simply requires that all electric equipment be
provided with switches or other controls that are safely designed,
constructed, and installed. This reference adds little or nothing of
substance to the requirements of this paragraph, and has not been
adopted in the final rule.
Paragraph (e) adopts the proposed requirement that each motor and
charging generator be protected from overload by an automatic
overcurrent device. This requirement is necessary to ensure proper
deenergization of circuits and equipment in the event of overcurrent
conditions such as arcing and motor overheating, and, when complied
with, will minimize resulting fire hazards. The final rule also adopts
the proposed provision that one device will be acceptable when two
motors of the same rating operate simultaneously and perform virtually
the same duty.
The requirements of paragraph (f), like the proposal, address
conductor size and capacity. Proper selection of circuit conductors of
adequate size and current carrying capacity and with insulation
compatible with the circuit voltage depends on the environmental
conditions under which the conductors will be used. Conductor size and
capacity are also important in minimizing overload and short circuit
conditions which could cause a fire. The final rule adopts the proposed
requirements that each ungrounded conductor have insulation compatible
with the impressed voltage, and that insulation materials be resistant
to deterioration from engine heat and oil. The final rule, like the
proposal, also requires that electric conductors meet the requirements
of existing Secs. 75.513 and 75.513-1, except for electrical conductors
for starting motors, which must only comply with the performance-
oriented requirements of Sec. 75.513. Existing Sec. 75.513 provides
that all electric conductors shall be sufficient in size and have
adequate current carrying capacity and be of such construction that a
rise in temperature resulting from normal operation will not damage the
insulating material. Existing Sec. 75.513-1 provides that an electric
conductor is not of sufficient size to have adequate current carrying
capacity if it is smaller than provided for in the National Electric
Code of 1968.
Existing Secs. 75.513 and 75.513-1 were developed for electrical
equipment used in outby locations, but they are also suitable for
application to all nonpermissible diesel- powered equipment. Greater
flexibility is provided for electric conductors for starting motors,
which are not required to meet the size and carrying capacity
requirements under Sec. 75.513-1, but must only comply with the
performance requirements of Sec. 75.513. This is because the conductor
size requirements in the 1968 National Electric Code are determined
based on the motor running at maximum load, with no allowance for the
type of duty. The conductor sizes specified in the Code would therefore
not be appropriate for starting motors, which typically run for only a
very short period of time.
Several commenters objected to the requirement in the proposed rule
that conductors for equipment or accessories added to a vehicle's
electrical system after manufacture not be smaller than No. 14 AWG in
size, stating that some components were not readily available with wire
sizes compatible with this requirement. In response to this comment and
in light of the requirements that have been adopted in the final rule,
which will provide adequate protection, the proposed size restriction
on certain conductors is not adopted in the final rule.
Since damaged or defective conductors or components may present
potential fire hazards, paragraphs (g) and (h) address the protection
of electric circuits and components. Paragraph (g), like the proposal,
requires all wiring to have adequate mechanical protection to prevent
damage to the cable that might result in short circuits. Paragraph (h)
adopts the proposed requirement that sharp edges and corners be removed
at all points where there is a possibility for damaging wires, cables,
or conduits by cutting or abrasion. The insulation of the cables within
a battery box is also required to be protected against abrasion. These
paragraphs ensure that circuits are physically protected and secured
from movement or displacement caused by vibration, as well as from
cutting or abrasion. The proposed rule would have included the
additional requirements that wiring have adequate electrical protection
to prevent cable damage, and that wiring be installed in accordance
with existing Sec. 75.515, as applicable. The reference to electrical
protection in the proposal was determined to be redundant, and has not
been adopted in the final rule. The reference to existing Sec. 75.515
in the proposal has also not been adopted in the final rule, because it
simply restates requirements already included in the final rule.
Paragraph (i) requires electrical connections and splices to be
electrically and mechanically efficient, in addition to having adequate
insulating properties. Insulating material would be required in
applications where space is limited and where the possibility exists of
arcs striking metal walls or parts. These precautions minimize fire
hazards from improper or loose connections and splices as well as
insufficient electrical clearances, which could cause a fire due to
conductor overheating or electrical arcing. In response to comments,
specific references to bolted connectors and to existing Sec. 75.514
have been deleted and replaced with more performance-oriented
requirements.
Paragraph (j) of the final rule, like the proposal, requires
storage batteries to be secured in place to prevent undue movement and
protected from external damage. Batteries not protected from damage by
their location on the equipment are required to be housed in a battery
box.
Paragraphs (k) through (o) of the final rule set forth requirements
for battery box construction, and are adopted from the proposal with
slight revision. These requirements provide for a substantially
constructed battery enclosure and address battery insulation,
ventilation, and chemical reaction from electrolyte. A number of
commenters suggested that more performance-oriented requirements be
adopted for battery box construction. However, the proposed design
specifications have been retained in the final rule because they set
forth the minimum construction requirements needed to protect a battery
from external damage. One commenter related an incident where a battery
case had deteriorated, resulting in arcing and sparking between the
battery terminal and the frame of the machine. Other reports of fires
from the Ontario fire accident data indicate that a number of fires had
been caused by batteries that were not secured in place or adequately
protected from external damage. The minimum design and construction
requirements for battery boxes in the final rule are necessary to
reduce these types of hazards.
Paragraph (k) provides that the battery box, including the cover,
must be constructed of steel with a minimum thickness of \1/8\ inch, or
of a material other than steel that provides equivalent strength. One
commenter specifically
[[Page 55472]]
cited the proposed \3/16\-inch thickness requirement as an example of
an unnecessary design requirement. This requirement has been changed to
\1/8\-inch minimum thickness to conform to existing part 7 requirements
for battery boxes containing batteries no greater than 1,000 pounds.
Thinner battery box cross sections would not provide adequate
protection for the battery and could result in a fire or explosion.
Paragraph (l) provides that battery-box covers must be lined with a
flame-resistant insulating material permanently attached to the
underside of the cover, unless equivalent protection is provided.
Battery-box covers must also be provided with a means for securing them
in a closed position. At least \1/2\-inch of air space must be provided
between the underside of the cover and the top of the battery,
including terminals. Paragraph (m) requires battery boxes to be
provided with ventilation openings to prevent the accumulation of
flammable or toxic gases or vapors within the battery box. The size and
locations of openings for ventilation must prevent direct access to
battery terminals. Paragraph (n) requires the battery to be insulated
from the battery-box walls and supported on insulating materials.
Insulating materials that may be subject to chemical reaction with
electrolyte must be treated to resist such action. Finally, paragraph
(o) requires drainage holes in the bottom of each battery box.
Stationary unattended diesel-powered equipment. The Diesel Advisory
Committee recommended that stationary unattended diesel-powered
equipment be prohibited where permissible electric equipment is
required, and that stationary unattended equipment used elsewhere in
the mine be provided with the fire prevention features required for
electrical installations and mobile diesel-powered equipment. The
Committee recommended that stationary unattended equipment be equipped
with specific machine features, such as surface temperature controls,
an automatically and manually actuated fire suppression system, an
engine shutdown device, and a means to shut down the engine from the
surface. The Committee also recommended that stationary unattended
equipment be housed in a fireproof enclosure ventilated to a return air
course.
Section 75.1910 of the proposed rule incorporated the
recommendations of the Advisory Committee for stationary unattended
equipment. Specifically, proposed Sec. 75.1910 would have prohibited
stationary unattended diesel-powered equipment in areas of the mine
where permissible electric equipment was required or in the primary
escapeway. Stationary unattended equipment located in other areas of
the mine would have been required to have a diesel power package
approved under subpart F or G of part 7. Additional safety features
were proposed for this equipment, including fuel system requirements,
limitations on storage of the equipment fuel supply, and a methane
monitor that would shut down the engine in the presence of 1.0 percent
concentration of methane.
A number of commenters were concerned that the proposed rule dealt
with stationary unattended diesel-powered equipment differently than
existing standards addressed unattended electrical equipment, and
imposed unnecessary restrictions. These commenters stated that it was
excessive to require approved power packages on equipment when the
equipment is already housed in a noncombustible enclosure, vented to a
return air course, protected by an automatic fire suppression system,
and equipped with a device that shuts down the equipment and sounds an
alarm at an attended surface location. Several commenters stated that
unattended electric equipment, which they believed presented similar
ignition sources, was not required to have methane monitors, and that
such monitors were not necessary, given the outby locations where
stationary nonpermissible equipment would operate.
Other commenters favored a complete prohibition of unattended
diesel equipment in underground coal mines, stating that diesel
equipment presented too great a fire hazard to allow it to be operated
unattended, even with the imposition of rigid safety requirements. One
commenter referred to the 1984 Wilberg Mine disaster, where a fire
started by an unattended electrical compressor killed 27 miners. In the
alternative, these commenters recommended that extensive additional
requirements be imposed on stationary unattended equipment, including a
requirement that the equipment be permissible, and that the enclosure
housing the equipment meet a 2-hour fire resistance test.
One commenter stated that there should be clarification of what
constitutes ``stationary'' versus ``portable'' equipment. The commenter
pointed out that some types of equipment, such as compressors, are
portable because they are capable of being transported by rail or
otherwise carried, but that the equipment can also be placed in a
remote location and operated there for an indefinite period of time.
In considering these comments, MSHA reviewed data to determine the
types of equipment that would be affected by the proposed requirements
for stationary unattended equipment. This review revealed that there
were approximately 200 pieces of equipment that were currently being
operated either as stationary unattended equipment or as portable
attended equipment. Equipment such as air compressors, generators, mine
sealant machines, hydraulic power units, rock dusters, water spray
units, and welders fell into this category. Water spray units are used
to wash mining equipment; mine sealant machines apply sealants to
stoppings or mine surfaces; hydraulic power units are used to operate
certain special purpose tools; rock dusters are used to apply rock dust
to mine surfaces; and diesel-powered welders are used where electric
power is not readily available. An operator must be present to perform
the main function of all of these types of equipment, i.e., welding,
rock dusting, etc.
MSHA's review also revealed that diesel-powered generators are
typically used to provide electrical power to move equipment with
electric motors from place to place in the mine. An equipment operator
is also in attendance when this type of equipment is being used.
Finally, MSHA's review also indicated that diesel-powered compressors
are used in a manner similar to hydraulic power units, with an operator
in attendance, to provide a source of compressed air to operate tools
such as pneumatic hammers and drills.
From this review, MSHA has concluded that diesel-powered equipment
is not commonly operated unattended in a permanent location, but
instead is operated with a person in close proximity. The final rule
includes a definition of what constitutes attended diesel-powered
equipment in Sec. 75.1908, which provides that the equipment must
either be operated by a miner, or located within 500 feet of a job site
where a miner is located. Essentially all of the diesel-powered
equipment currently operated in underground coal mines is ``attended''
under the final rule's definition. In light of this determination, and
also in light of the serious concerns expressed by some commenters
about the possible fire hazards presented by unattended diesel-powered
equipment operating underground, Sec. 75.1916(d) of the final rule
prohibits the operation of unattended diesel-powered equipment in
underground coal mines.
[[Page 55473]]
Consequently, the proposed requirements addressing the operation of
stationary unattended diesel-powered equipment are not adopted in the
final rule.
As a result of the final rule's prohibition against operation of
unattended diesel-powered equipment in underground coal mines,
conforming amendments are necessary to several existing standards,
primarily to delete unnecessary references to unattended diesel-powered
equipment. Existing Sec. 75.360 lists the locations where preshift
examiners must examine for hazardous conditions, test for methane and
oxygen deficiency, and determine if the air is moving in the proper
direction. The final rule deletes from these locations the reference in
Sec. 75.360(b)(7) to ``where unattended diesel equipment is to
operate.'' Additionally, existing Sec. 75.380(f)(3)(i) included a
prohibition against operation in the primary escapeway of unattended
diesel equipment without an automatic fire suppression system. This
reference is deleted by the final rule.
Finally, existing Sec. 75.344 deals with the use of air compressors
underground, including unattended diesel compressors. The final
ventilation rule that was published in October 1989 made clear that the
application of the requirements of Sec. 75.344 to diesel compressors
would be removed when the final rule for diesel equipment was
promulgated. [54 FR 40950]. The reference to diesel compressors in
paragraph (d) of Sec. 75.344 is therefore removed by the final rule.
Section 75.1911--Fire Suppression Systems For Diesel-Powered Equipment
And Fuel Transportation Units
Section 75.1911 of the final rule establishes requirements for the
design, installation, and maintenance of fire suppression systems used
on diesel-powered equipment and fuel transportation units in
underground coal mines. Under the final rule, both permissible and
nonpermissible diesel-powered equipment is required to be equipped with
fire suppression systems. The requirement for installation of fire
suppression systems on permissible diesel-powered equipment is
contained in the final rule at Sec. 75.1907(b)(2),and for
nonpermissible equipment at Sec. 75.1909 (h), (i), and (j)(3).
Nonpermissible diesel-powered equipment typically includes scoops,
personnel carriers, and pickup trucks.
The Diesel Advisory Committee recommended that fire suppression
systems be required on certain types of diesel-powered equipment, in
addition to surface temperature controls, to address fire hazards
created by other machine system malfunctions such as brake components
overheating, severing of a fuel line or hydraulic line, and electric
component short-circuiting. The Committee made a number of
recommendations regarding the application of fire suppression systems
to specific types of equipment such as nonpermissible equipment,
limited class equipment, and stationary equipment. The proposed rule
included design, installation and maintenance requirements for fire
suppression systems on diesel-powered equipment and fuel transportation
units. These requirements would have been applicable to approved
equipment, limited class equipment, and fuel transportation units, both
self-propelled and towed.
Commenters to the proposed rule generally accepted the need for
fire suppression systems on diesel-powered equipment operated in
underground coal mines. However, comments varied on what the
requirements for fire suppression systems should be. Some commenters
recommended that only manufacturer's requirements for design,
installation and maintenance be used. Other commenters suggested a more
detailed approach and recommended that the final rule outline specific
requirements for fire suppression systems.
Fire suppression systems are necessary on diesel-powered equipment,
including fuel transportation units, because of the numerous fuel
sources, including diesel fuel, hydraulic fluid, and combustible
material, and several potential ignition sources, such as hot exhaust
components, dragging brakes, and electrical wiring on this type of
equipment. Accident reports describe machine fires caused by hot
exhaust components, dragging brakes and shorted electrical components
igniting diesel fuel, hydraulic fluid, brake fluid, lube oil, and other
combustible materials, such as electrical insulating material.
Fire suppression systems are designed to extinguish fires quickly,
in their incipient stage, and to reach all locations where a fire may
occur. This is important for diesel-powered equipment because a fire
must be extinguished quickly before fuel sources can further propagate
a fire. For example, if a fire is not extinguished at an early stage,
leaking diesel fuel or hydraulic fluid can fuel a fire and result in an
increase in the intensity and size of the fire. Also, promptly
extinguishing a fire prevents reignition through the contact of hot
surfaces created by the fire with leaked or spilled diesel fuel or
hydraulic fluid. Fixed fire suppression systems also offer two
advantages over portable fire extinguishers: fast attack and
application of the suppressant to difficult-to-reach areas on and under
diesel machines where fires may occur.
An automatic fire suppression system uses a supplemental detection
device to sense an early warning of a fire. The fire detection system,
which is generally actuated by either smoke or heat, automatically
sends a signal to the system for the discharge of suppressant agent.
Manual fire suppression systems require a person to actuate the fire
suppression system by either pushing a button or throwing a switch to
discharge the fire suppressant agent to the hazard. Both automatic and
manual fire suppression systems utilize a network of piping and nozzles
to allow suppressant agent to be released and distributed directly at a
predetermined fire hazard.
Under the final rule, fire suppression systems are required to
provide fire suppression and, if an automatic system is installed, fire
detection for the engine, transmission, hydraulic pumps and tanks, fuel
tanks, exposed brake units, air compressors, battery areas and other
areas as necessary. The final rule also requires that automatic fire
suppression systems include audible and visual alarms to warn of fires
or system faults and automatic engine shutdown in the event of a fire.
In addition, the final rule requires all fire suppression systems to be
tested and maintained in accordance with manufacturer's
recommendations. Finally, the rule establishes certain recordkeeping
requirements for faulty fire suppression systems that are found during
inspection and testing.
Paragraph (a) of this section of the final rule provides that the
fire suppression system required by Secs. 75.1907 and 75.1909 must be a
multipurpose dry chemical type (ABC) fire suppression system listed or
approved by a nationally recognized independent testing laboratory and
appropriate for installation on diesel-powered equipment and fuel
transportation units.
The proposed rule would have required an automatic multipurpose dry
powder type fire suppression system suitable for its intended
application and listed or approved by a nationally recognized
independent testing laboratory on diesel-powered equipment and portable
diesel-powered equipment and fuel transportation units. The proposal
would have further established fire suppression requirements for
approved equipment, limited class equipment, and fuel transportation
units, both self-propelled and towed.
[[Page 55474]]
Commenters expressed support for automatic fire suppression systems
on portable or unattended diesel-powered equipment. A number of
commenters, however, stated that automatic fire suppression systems are
not needed on self-propelled diesel-powered equipment, because this
type of equipment is attended by an equipment operator. These
commenters suggested that mine operators should have the option of
providing either manual or automatic fire suppression systems on self-
propelled diesel-powered equipment, stating that the equipment operator
is in the best position to detect incipient fires on the machine and is
able to actuate a manual fire suppression system more easily than an
automatic system. Some commenters stated that automatic fire
suppression systems are not necessary on mobile diesel-powered
equipment because this type of equipment will already be required to
have fire protection and shutdown features. Commenters also stated that
automatic systems can require extra maintenance and are susceptible to
vibration, which can cause them to discharge unexpectedly. In addition,
commenters stated that automatic fire suppression systems should not be
required on vehicles with surface temperature controls, such as
permissible vehicles, because compatible permissible systems were not
available at the time of the proposal.
Other commenters supported the proposal for automatic fire
suppression systems on all types of diesel-powered equipment. In
testimony before the Diesel Advisory Committee, equipment manufacturers
and mine operators endorsed the use of automatic fire suppression
systems on several types of diesel-powered equipment and gave examples
of current applications. Other commenters to the proposal observed that
it might be difficult for an equipment operator to actuate a manual
system depending on the type and size of a fire. These commenters
expressed concern that an equipment operator could be overcome by the
effects of a fire or explosion and not be able to manually extinguish
the fire. Some commenters also expressed concern that a manually-
actuated system would be ineffective for a fire that started after the
equipment had been shut off and the equipment operator had left the
area.
Paragraph (a) of this section of the final rule does not adopt the
proposed requirement for installation of an automatic fire suppression
system on all mobile diesel-powered equipment. Instead, the final rule
establishes requirements for both manual and automatic fire suppression
systems. The type of fire suppression system required for installation
on diesel-powered equipment is specified in Sec. 75.1907(b)(2) for
permissible equipment, and Sec. 75.1909 (h), (i), and (j)(3) for
nonpermissible equipment.
The Ontario fire accident data indicated that heavy-duty diesel-
powered equipment of the type defined in the final rule at
Sec. 75.1908(a) presents a much greater fire hazard than light-duty
equipment defined under the final rule at Sec. 75.1908(b). The data
showed that heavy-duty diesel-powered equipment, which includes
equipment that cuts or moves rock or coal, equipment that performs
drilling or bolting functions, and fuel transportation units, had 247
fires (85 percent) of the total number of fires. Heavy-duty equipment
frequently works under load and can develop large areas of hot engine
surfaces. This equipment is prone to mechanical breakdown, especially
hydraulic hose and electrical cable failure, creating a serious risk
that the equipment will develop both an ignition source and provide a
source of fuel for a fire.
By contrast, light-duty diesel-powered equipment, which under the
final rule includes supply vehicles, maintenance vehicles, personnel
carriers, and other equipment not used to move rock or coal, accounted
for 43 (15 percent) of the total number of fires. Light-duty equipment
is not used in the actual mining process and is generally not worked
very hard and typically used only intermittently during a shift. While
over a third of the fires on heavy-duty equipment were started by hot
engine surfaces, fewer than 10 percent of the fires on light-duty
equipment were started by hot engine surfaces. Fires related to the
electrical system accounted for 60 percent of the light-duty equipment
fires. Electrical fires tend to smolder and provide more time for
action to be taken to extinguish the fires than do diesel fires.
Although light-duty equipment still poses a fire risk, this risk
can be adequately addressed by fire suppression systems which take into
account the manner in which light-duty equipment is used and the types
of fires that typically occur on it. The final rule, therefore, does
not adopt the proposal that automatic fire suppression systems be
installed on all diesel machines.
A manually-actuated fire suppression system provides adequate
protection on light-duty self-propelled equipment. This type of
equipment is attended by its operator at all times that it is operating
as required by Sec. 75.1916(d) of the final rule. As discussed by
several commenters to the proposal, it has been their experience that a
well-maintained manually-actuated fire suppression system is
appropriate if the equipment is attended. These commenters stated that
manually-actuated fire suppression systems are adequate in conjunction
with additional protective features for fuel, hydraulic, and electrical
systems, to provide fire protection on outby diesel-powered equipment.
In addition to a manual fire suppression system, protective features
for fuel, hydraulic, and electrical systems are required on both heavy-
duty and light-duty nonpermissible equipment under Secs. 75.1909 and
75.1910 of the final rule.
Automatic fire suppression systems are necessary on equipment that
poses a higher fire risk. This includes heavy-duty equipment, which
presents an increased fire hazard as discussed above. It also includes
equipment for which the operator is not immediately present at the
controls of the machine at all times it is operated, such as
compressors. Good fire fighting practice requires that the fire be
attacked as early as possible. Further, several reports indicate that
the rapid growth of fire prevented the equipment operator from
actuating the manual fire suppression system. Automatic systems provide
a fast response without operator intervention. Compressors and other
non-self-propelled equipment frequently operate for long periods of
time under high load. This results in sustained high engine surface
temperatures, which can provide an ignition source for a fire and
increase the likelihood of a a mechanical failure providing a fuel
source for a fire. Also, the individual operating the compressor may be
some distance from the machine, and would not be able to promptly
actuate the fire suppression system. To address these hazards, the
final rule adopts the proposed requirement for automatic fire
suppression systems for heavy-duty and non-self-propelled equipment.
One commenter to the proposal stated that the requirement in
paragraph (a) that the ``system be suitable for the intended
application'' was ambiguous and could be subject to different
interpretations. This commenter stated that the term ``suitable'' could
refer to a system that is suitable for a particular type of fire (class
B flammable or combustible liquid fire) or it could mean that the
system has a sufficient capacity to extinguish a fire on a particular
piece of equipment. Other commenters recommended that the final rule
specify the capacity of the fire suppression system.
The final rule responds to commenters' concerns by requiring that
[[Page 55475]]
fire suppression systems be multipurpose dry chemical type (ABC) fire
suppression systems listed or approved by a nationally recognized
independent testing laboratory, and appropriate for installation on
diesel-powered equipment. The final rule does not adopt the language
``suitable for the intended application.''
The capacity and suitability of fire suppression systems for
protecting against specific fire hazards are specified as part of the
listing or approval by the nationally recognized independent testing
laboratory. The nationally recognized independent testing laboratory
system listing or approval does not necessarily designate the system
for a specific type of equipment, such as fuel transportation units or
even diesel-powered equipment. Instead, the listing or approval uses a
more general description such as mobile mining equipment or vehicle
protection. Listing or approval by a nationally recognized independent
testing laboratory ensures that a fire suppression system is properly
designed for a particular type of fire protection hazard by putting the
system through a series of specific performance tests. The system must
also meet rigid design requirements in order to gain approval or
listing.
Fire suppression systems should be installed by a qualified
individual following the installation and maintenance instructions in
the system manufacturer's installation manual. The sizing of a fire
suppression system is dependent on the number of nozzles needed to
adequately cover all of the fire hazard areas that have been
identified. The number of dry chemical canisters required will be
proportional to the number of hazard areas that must be covered by the
nozzles. This information can be obtained from the installation manual
that is part of the listing or approval documentation. Other
installation considerations, such as proper location and guarding of
nozzles and other system components to prevent damage, are addressed in
the system's installation manual. In addition to the installation
requirements in the manual, follow-up maintenance and inspection
procedures are provided.
Also modified in this section from the proposal is the term
``chemical'' replacing the term ``powder'' and the addition of the
letter references ``ABC'' for the three classes of fire. These
modifications are made in response to commenters' requests for
clarification and to incorporate more appropriate terminology.
A multipurpose dry chemical type system is capable of suppressing
the three classes (ABC) of fires on diesel-powered equipment. A class A
fire refers to fires of combustible solid materials such as paper,
rubber, textiles, and cloth, and would typically involve such items as
tires, hosing or seats on diesel-powered equipment. A class B fire on
diesel-powered equipment would involve diesel fuel. Class C fires
involve electrical components, and could include such components as
lights, pumps, and components of the control panel on diesel-powered
equipment. A multipurpose dry chemical type agent is specifically
designed to extinguish ABC class fires.
Paragraph (a)(1) of the final rule, like the proposal, requires
that the fire suppression system be installed in accordance with the
manufacturer's specifications and the limitations of the nationally
recognized independent testing laboratory listing or approval.
Commenters generally expressed support for this aspect of the proposal.
This requirement ensures that the system is installed within the limits
defined by the listing or approval organization and as specified by the
fire suppression system manufacturer. Since the system already is
performance-tested to a specific standard and in certain
configurations, it must be installed within these parameters to be
effective.
Paragraph (a)(2) adopts the requirement from the proposal that the
fire suppression system be installed in a protected location or guarded
to minimize physical damage from routine vehicle operations. No
specific comments were received on this aspect of the proposal. In
order for fire suppression systems to work properly, they must not be
subjected to damage from the mining environment. Damage to any part of
the fire suppression system can result in a malfunction of the entire
system and in the system not responding to a fire. For example, a rock
fall can pinch a hose or crush a sensor and create faults that can
disable either the entire system or a portion of the system that covers
a certain area of the machine.
Paragraph (a)(3), like the proposal, requires that the suppressant
agent distribution tubing or piping be secured and protected against
damage, including pinching, crimping, stretching, abrasion, and
corrosion, and that the discharge nozzles be positioned and aimed for
maximum fire suppression effectiveness in the protected areas. No
specific comments were received on this aspect of the proposal. During
the normal operation of diesel-powered equipment in the confined space
of a coal mine, a fire suppression system can become damaged from
collision or nozzles positioned at a specific predetermined location
can be redirected away from a fire hazard.
Paragraph (a)(4), like the proposal, requires that fire suppression
nozzles also be protected against the entrance of foreign materials. No
specific comments were received on this aspect of the proposal. The
openings in the nozzles used on multipurpose dry chemical fire
suppression systems can be as small as \1/8\ of an inch. If material
such as mud, coal dust, or rock dust enters the nozzle, it can prevent
the chemical agent from discharging entirely, or alter the pattern and
coverage of fire suppressant.
Paragraph (b) of the final rule requires fire suppression and, if
the system is automatic, fire detection for certain coverage areas on
diesel-powered equipment. Under the final rule, the coverage areas
include the engine (including the starter), transmission, hydraulic
pumps and tanks, fuel tanks, exposed brake units, air compressors and
battery areas on diesel-powered equipment and electric panels or
controls used on fuel transportation units. This requirement ensures
that fire detection and fire suppression are provided with coverage for
key areas of diesel-powered equipment and fuel transportation units.
Although the listing or approval generally describes areas on
equipment that pose a fire hazard, it does not specifically identify
which hazards must be covered by fire suppression. The final rule's
requirement for specific fire suppression coverage for certain areas on
diesel-powered equipment is supported by the Ontario fire data. The
data showed that engine fires accounted for 99 (34 percent) of the
total number of fires on diesel-powered equipment. Included in engine
fires were 10 compressor fires, 27 hydraulic system fires, 11
transmission fires, and 7 fuel tank fires. The Ontario fire data also
indicate 32 battery fires and 55 brake fires.
The scope of paragraph (b) is expanded to include the starting
mechanism on diesel-powered equipment. This responds to commenters'
recommendations that foreign fire data be evaluated to establish
criteria for fire protection on diesel-powered equipment. The Ontario
fire accident data indicate that starters, starter solenoids, and the
wiring associated with these components present a fire hazard. The data
showed 21 (17 percent) of the electrical fires on self-propelled
diesel-powered equipment were caused by starter circuits. Also, the
proposal included the engine compartment as an area to be
[[Page 55476]]
covered by the fire suppression system. The specific reference to the
starter area in the final rule clarifies that the starter area of the
engine compartment be covered by the fire suppression system.
The proposed rule specified fire suppression system coverage areas
for various types of limited class equipment. Because of the different
fire hazards presented by the various types of equipment listed in the
proposal, separate provisions in proposed paragraph (b)(1) were
included. In the final rule the limited class category of light-duty
equipment is expanded to include a range of equipment types, beyond the
types defined in the proposal, and the requirements for coverage areas
have been combined.
Proposed paragraph (b)(2) has not been adopted in the final rule to
the extent that it would have specified coverage areas around fuel
transportation units in response to commenters' statements that fuel
tanks by themselves do not constitute a fire hazard, and only need
coverage if an associated ignition source is present. Proposed
paragraph (b)(3), which would have required fire suppression coverage
for fuel containers and electric panels or controls used during fuel
transfer operations on fuel transportation units, has not been adopted
because the term ``container'' is no longer used in the final rule. The
phrase ``during fuel transfer operations'' was not adopted from the
proposal to eliminate the inference that only electric panels or
controls used during fuel transfer operations must have coverage. Under
the final rule, electrical components installed on fuel transportation
units must be covered by fire suppression systems. However, a vehicle's
instrument panel located in the operator's compartment of the machine
would not be considered ``electrical panels and controls.'' Expelling
fire suppressant in the operator's compartment would create other
hazards for the equipment operator such as a cloud of fire suppressant
which could limit visibility.
Paragraph (c), like the proposal, requires that automatic fire
suppression systems include audible and visual alarms to warn of fires
or system faults. No specific comments were received on this aspect of
the proposed rule. This requirement provides a means for immediate
notification of the equipment operator, both audibly and visually, when
the system detects a fire on the machine or a problem with the fire
detection device. The audible and visual indication of fire detection
can alert the equipment operator of the imminent discharge of the
chemical agent and the engine shutdown required by paragraph (d).
Paragraph (d) of the final rule adopts the proposed requirement
that the fire suppression system provide for automatic engine shutdown.
The final rule also provides that if the fire suppression system is
automatic, engine shutdown and discharge of suppressant agent may be
delayed for a maximum of 15 seconds after the fire is detected by the
system. Commenters expressed support for this aspect of the proposed
rule.
The engine shutdown requirement is intended to prevent an engine
from continuing to run once the system has been actuated, either
automatically or manually. This will prevent the engine from pumping
diesel fuel or hydraulic fluid through a leaking fuel line or hydraulic
hose, fueling the fire that the fire suppression system is attempting
to extinguish. Since fire suppression systems are designed to suppress
fires in their incipient stages, the contribution of additional fuel to
the fire may render the system ineffective. The Ontario accident data
included a number of machine fires where the engine continued to feed
the fire with diesel fuel or hydraulic fluid, reducing the
effectiveness of the system's ability to suppress the fire. In
addition, the engine shutdown feature prevents the engine cooling fan
from dispersing the fire suppressant agent before it extinguishes the
fire. A maximum of 15 seconds delay between the time of fire detection
and actuation provides a limited period of time for the equipment
operator to stop and exit the machine before the machine engine shuts
down.
Paragraph (e) of the final rule adopts the proposed requirement
that the fire suppression system be operated by at least two manual
actuators. One actuator must be located on each side of the equipment,
and if the equipment is provided with an operator's compartment, one
actuator must be located in the compartment within easy reach of the
equipment operator.
Several commenters expressed the opinion that two manual actuators
were unnecessary on small units of diesel equipment, such as tractors,
when the second actuator would have to be installed in close proximity
to the engine. Another commenter urged that actuators be separated from
each other by a means of a check valve or other device to allow the
system to operate even if there is an open line in the actuation
circuit.
Two actuators for a fire suppression system are important to afford
ample opportunity to initiate the system, even on small units of
diesel-powered equipment. For example, if only one actuator were
located on the side of a piece of equipment, the equipment operator
might be unable to access the actuator due to the confined spaces in an
underground coal mine, or because the fire ignited in the same location
as the actuator. The final rule requirement for two manual actuators is
also consistent with existing Sec. 75.1107 for dry chemical fire
suppression systems for electric equipment.
The final rule does not include a requirement for a check valve
between the actuators for fire suppression systems. This is part of the
system design and is more appropriately addressed by the system
manufacturer and the listing or approving nationally recognized
independent testing laboratory.
Paragraph (f) adopts the proposed requirement that the fire
suppression system must remain operative in the event of engine
shutdown, equipment electrical system failure, or failure of any other
equipment system. No specific comments were received on this aspect of
the proposed rule. This requirement is intended to ensure that the
functioning of the system is not dependent on any external power
source, such as an engine-driven alternator, vehicle battery, or the
proper operation of any other machine system.
Paragraph (g), like the proposal, requires that the electrical
components of each fire suppression system installed on diesel-powered
equipment used where permissible electric equipment is required be
permissible or intrinsically safe, and that such components be
maintained in permissible or intrinsically safe condition. This
provision requires that automatic fire suppression systems be certified
or approved by MSHA under part 18.
A number of commenters to the proposal stated that intrinsically
safe vehicle-type automatic fire suppression systems were not
available. Currently, however, two fire suppression system
manufacturers have obtained approval under part 18 for their automatic
fire suppression systems.
Paragraph (h) adopts the requirement from the proposal that
electrically operated detection and actuation circuits be monitored and
provided with status indicators showing power and circuit continuity.
If the system is not electrically operated, a means must be provided to
indicate the functional readiness status of the detection system. These
features notify the equipment operator or maintenance person of the
functional readiness status of both the detection and actuation circuit
and the power source. No specific comments
[[Page 55477]]
were received on this aspect of the proposed rule.
Currently at least one manufacturer is marketing an automatic fire
suppression system with these electrical features on both permissible
and nonpermissible systems. There is also an automatic system which is
not electrically operated and employs a pressurized cylinder to
disperse the suppressant. A pressure gauge on the cylinder is
considered sufficient to indicate the condition of the system.
Paragraph (i) requires that each fire suppression system be tested
and maintained in accordance with the manufacturer's recommended
inspection and maintenance program and as required by the nationally
recognized independent testing laboratory listing or approval. It also
requires fire suppression systems to be visually inspected at least
once each week by a person trained to make such inspections.
The proposed rule would have required each fire suppression device
to be visually inspected at the same interval by a person qualified to
make such inspections. The proposal also would have required that each
fire suppression device be tested and maintained in accordance with
applicable requirements in Sec. 75.1100.
Commenters to the proposal generally expressed support for required
maintenance of fire suppression systems installed on diesel-powered
equipment. Some commenters, however, recommended that a maintenance
program specifically designed for fire suppression systems be developed
at each mine. One commenter stated that a visual inspection of fire
suppression systems on diesel-powered equipment would not be adequate
and recommended that fire suppression systems be maintained in
accordance with the manufacturer's guidelines by either outside
entities qualified by the equipment manufacturer or through a program
to qualify individuals at the mine. Another commenter to the proposal
recommended that the manufacturer's inspection and maintenance program
be referenced in lieu of the requirements in Sec. 75.1100. One
commenter stated that automatic fire suppression systems are more
difficult to maintain than manual systems, but that both types of
systems should be inspected monthly and maintained semi-annually as a
minimum. Another commenter expressed concern that certain critical
internal components of a fire suppression system could be checked
simply by a visual inspection.
Under the final rule, the weekly visual inspection is not intended
to be an in-depth inspection. The weekly visual inspection is intended
to be a quick check to determine if defects, such as disconnected hose
lines or altered nozzles, are readily apparent. The in-depth inspection
takes place as part of the manufacturer's recommended testing and
inspection procedure also required under the final rule. Fire
suppression system manufacturers are most familiar with the design and
operation of their systems and are best able to identify the components
that need maintenance as well as the type and frequency of maintenance.
Adequate maintenance is essential because of the importance of these
systems in suppressing machine fires. Maintenance and testing
requirements for fire suppression systems are included in the final
rule in addition to the requirement for a weekly visual inspection.
The manufacturer's inspection and maintenance procedures are
typically spelled out in great detail in the manufacturer's manual and,
depending on the operating environment, include the recommended
inspection intervals. In addition, these inspection and maintenance
procedures are evaluated as part of the system's approval or listing by
a nationally recognized independent testing laboratory.
The requirement in this paragraph is identical to the requirement
in existing Sec. 75.1107-16(a). However, the fire suppression system
requirements in Secs. 75.1107-3 through 75.1107-16 cannot be directly
applied to diesel-powered equipment for several reasons. Any
modification of these existing requirements by inserting the term
``diesel-powered'' in the regulatory language would result in an
extremely confusing regulation. Also, the fire hazards presented by
diesel-powered equipment are different from those on electric-powered
equipment, due to the close proximity of large quantities of hydraulic
oils and fuels to the heated diesel engine exhaust. The single
modification made to this paragraph was replacing the term ``device''
with the term ``system''. This was done because MSHA intends that the
whole system be inspected and not just individual components of the
system.
Although automatic systems have additional components that must be
inspected and maintained, properly trained maintenance personnel should
have little difficulty satisfying these requirements. It is anticipated
that the training of the personnel assigned to perform the testing and
maintenance of fire suppression systems will be provided by the system
manufacturer or distributor. Additionally, automatic fire suppression
systems under the final rule are required to have a status monitoring
feature to tell the equipment operator or maintenance personnel that a
problem exists.
Section 75.1915(b)(3)(iv) of the final rule requires that the
training and qualification program for qualified persons working on
diesel equipment address tests and maintenance of fire suppression
systems. The qualified person conducting maintenance on fire
suppression systems on diesel-powered equipment should have sufficient
familiarity with the elements of the fire suppression system. A person
``trained'' to perform inspections and tests required by paragraph (i)
of this section of the final rule is not required to be a person
qualified under Sec. 75.1915. However, the final rule intends that the
person performing tests and inspections of fire suppression systems
have sufficient knowledge to determine whether a fire suppression
system is functioning properly. MSHA anticipates that since fire
suppression systems are common to both electric and diesel equipment,
the mine operator will work with either the fire suppression system
manufacturer or distributor to ensure that personnel responsible for
the maintenance of fire suppression systems are adequately trained.
Paragraphs (j) of the final rule establishes recordkeeping
requirements which address the inspection and maintenance requirements
for fire suppression systems set forth in paragraph (i). Paragraph (j)
of the final rule requires that persons performing inspections and
tests of fire suppression systems record results of tests and
inspections only when a fire suppression system does not meet the
installation or maintenance requirements of this section. Under these
circumstances, the person performing the inspection or test is required
to record the equipment on which the fire suppression system did not
meet the installation or maintenance requirements of this section, the
defect found, and the corrective action taken. The final rule also
requires that these records be kept either manually or electronically
in a secured manner that is not susceptible to alteration. Paragraph
(j)(3) requires that records be maintained at a surface location at the
mine for one year and made available for inspection by an authorized
representative of the Secretary and miners' representatives.
The proposal would have required that a record be kept of all
inspections and tests of fire suppression systems
[[Page 55478]]
and maintained at an appropriate location for each fire suppression
device. One commenter to the proposal recommended that, in order to
provide adequate maintenance of fire suppression systems, interested
parties be allowed to view the results of visual inspections recorded
in approved books. Another commenter recommended that records of
inspections be maintained on the surface by the operator so that they
would be available for MSHA verification. This commenter stated that
maintaining separate records for inspections of fire suppression
systems is an unnecessary burden for the mine operator. This commenter
stated that records kept on computers, as pre-shift examinations and by
normal maintenance inspections, would be adequate for documenting the
inspections conducted on fire suppression systems.
Office of Management and Budget guidance comments directed MSHA to
reexamine the recordkeeping requirements in the proposal and
recommended that the final rule require paperwork that was the least
burdensome necessary. MSHA has done so, and the final rule does not
adopt the proposal that all fire suppression system test and
maintenance results be recorded. In response to commenters and
consistent with other provisions of the final rule, paragraph (j)
requires that records of inspections and tests be made only when a fire
suppression system does not meet the installation or maintenance
requirements of this section. This requirement is important because if
a fire suppression system does not meet the installation or maintenance
requirements of this section, the defect could be sufficiently serious
to cause the system to fail in the event of a fire. This requirement is
intended to ensure that records are maintained and made available to
interested parties when a defect is found, and that the appropriate
level of mine management is made aware of defects requiring corrective
action.
The final rule does not specify a particular way of recording the
test and maintenance data, only that the records be located at the
surface of the mine. The records of the inspections and tests must be
made in a secure media not susceptible to alteration. A detailed
discussion of the subject of acceptable record books and electronic
records can be found under the heading ``Recordkeeping Requirements''
in the General Discussion section of this preamble.
The final rule does not adopt the requirement from the proposed
rule that records of inspections be maintained at an appropriate
location near each fire suppression system. Instead, paragraph (k) of
the final rule establishes the requirement recommended by a commenter
that records of inspections and tests be maintained at a surface
location at the mine. Storing records on the surface at the mine makes
them more accessible to interested parties. Also in response to
commenters, the final rule provides access to not only miners'
representatives but to authorized representatives of the Secretary.
This provision ensures that test and inspections of fire suppression
systems are being made and, when a defect is found, that corrective
action is taken.
Records for inspection of diesel-powered equipment are also
required under Sec. 75.1914(f)(2) of the final rule. However, the
recordkeeping requirement under paragraph (j) is not intended to be
duplicated. While Sec. 75.1914(f)(2) applies to diesel-powered
equipment, some diesel fuel transportation units may be portable
trailers with only electrical components and therefore would need to be
covered under the recordkeeping requirement under paragraph (j) of this
section. The only records required for fire suppression systems under
this section of the final rule are for tests and maintenance required
under paragraph (i).
Paragraph (k) adopts the proposed requirement that all miners
normally assigned in the active workings of the mine be instructed
about the hazards inherent to the operation of fire suppression
systems, and where appropriate, the safeguards available for each
system. This requirement is intended to ensure that all miners working
in areas where fire suppression systems operate are instructed in any
inherent hazards and necessary precautions associated with the
operation of these systems. The final rule modifies the proposal in
that the term ``device'' has been replaced by the term ``system'' to
clarify that this requirement applies to the entire fire suppression
system, not merely a component of it.
One commenter to the proposal agreed with the requirement that
miners be trained in the hazards and safeguards of fire suppression
systems, but recommended that such training be incorporated in the
annual refresher training required under existing Sec. 75.1101-23 for
the program of instruction, location and use of fire fighting
equipment. Under the final rule, it is anticipated that the instruction
on the hazards of fire suppression systems required by this paragraph
will be part of the Sec. 75.1101-23 instruction.
Paragraph (l) of this section of the final rule provides that, for
purposes of existing Sec. 75.380(f), a fire suppression system
installed on diesel-powered equipment and meeting the requirements of
Sec. 75.1911 is equivalent to a fire suppression system meeting the
requirements of Secs. 75.1107-3 through 75.1107-16.
Section 75.380 addresses requirements for escapeways in bituminous
and lignite mines. Section 75.380(f) specifies the equipment that can
be used in the primary escapeway and the type of fire suppression
system required to be installed on this equipment. Section 75.380(f)(4)
requires that each piece of mobile equipment operated in primary
escapeways, except for continuous miners and as provided in paragraphs
(f)(5), (f)(6) and (f)(7) of the section, be equipped with a fire
suppression system installed according to Secs. 75.1107-3 through
75.1107-16 that is: (1) manually operated and attended continuously by
a person trained in the system's function and use; or (2) a
multipurpose dry chemical type capable of both automatic and manual
activation. The requirement in Sec. 75.380(f)(4) for installation of a
fire suppression system that meets the requirements of Secs. 75.1107-3
through 75.1107-16 on equipment operating in the primary escapeway
presents a potential conflict with the requirement for installation of
a fire suppression system on diesel-powered equipment in Sec. 75.1911.
As noted earlier, several commenters to the proposed rule believed
that the requirements for fire suppression systems in Secs. 75.1107-3
through 75.1107-16 should be made applicable to diesel-powered
equipment. However, the requirements in Secs. 75.1107-3 through
75.1107-16 make specific reference to electric equipment and components
and are not practical for diesel-powered equipment. Any modification of
these existing requirements by inserting the term ``diesel-powered'' in
the regulatory language would result in an extremely confusing
regulation.
After a review of the issue, MSHA has determined that fire
suppression systems installed on diesel-powered equipment meeting the
requirements of Sec. 75.1911 afford at least equivalent protection to
fire suppression systems meeting the requirements of Secs. 75.1107-3
through 75.1107-16. Many of the requirements contained in
Secs. 75.1107-3 through 75.1107-16 are similar to those in
Sec. 75.1911. Both sections include requirements for: listed or
approved fire
[[Page 55479]]
suppression systems; the capacity and size of fire suppression system
hardware; a system design that will withstand the normal rigors of
mining; compatibility of the extinguishing agent with the mine
atmosphere; the system's ability to operate independently of an
equipment power supply; sensor operability status indication; and the
inclusion of manual actuators. Consequently, the final rule makes clear
that fire suppression systems meeting the requirements of Sec. 75.1911
will satisfy the requirements of Sec. 75.380(f)(4).
Section 75.1912 Fire Suppression Systems for Permanent Underground
Diesel Fuel Storage Facilities
This section of the final rule establishes requirements for the
design, installation and maintenance of fire suppression systems at
permanent underground diesel fuel storage facilities. Under the final
rule, a permanent underground diesel fuel storage facility is defined
as a facility designed and constructed to remain at one location for
the storage or dispensing of diesel fuel, which does not move as mining
progresses. Section 75.1903(a)(5) of the final rule requires that
permanent underground diesel fuel storage facilities be equipped with
an automatic fire suppression system that meets the requirements of
Sec. 75.1912.
The Diesel Advisory Committee recommended that automatic fire
suppression systems be used to address potential fire hazards from
ignition and fuel sources at permanent underground diesel fuel storage
facilities. The proposed rule included design, installation and
maintenance requirements for automatic fire suppression systems for
diesel fuel storage areas and stationary diesel-powered equipment.
Commenters to the proposed rule generally accepted the need for
fire suppression systems at permanent underground diesel fuel storage
facilities. However, comments varied on what the requirements for fire
suppression systems should be. Some commenters recommended that only
manufacturer's requirements for design, installation and maintenance be
used. Other commenters recommended a more detailed approach and
suggested that the final rule outline specific requirements for fire
suppression systems.
The storage of diesel fuel at permanent underground facilities
presents a limited fire hazard when fuel is contained in diesel fuel
tanks and safety cans constructed of noncombustible material. However,
diesel fuel does present a fire hazard when it is spilled from a tank
or leaked from a hose and comes into contact with an ignition source.
Spills and leaks of diesel fuel at permanent underground storage
facilities can occur when machinery is being refueled, when diesel fuel
is being placed in or taken out of storage tanks, or when tanks are
damaged or not properly maintained. Potential ignition sources at
permanent underground storage facilities include a running diesel
vehicle with hot surfaces or hot brake components, malfunctioning
electric valves, or pumps used to dispense diesel fuel.
Fire suppression systems are designed to extinguish fires quickly,
in their incipient stage, and to reach all locations where a fire may
occur. This is important at permanent underground diesel fuel storage
facilities because a fire must be extinguished quickly before fuel can
further propagate a fire. For example, if a fire is not extinguished at
an early stage, leaking diesel fuel can fuel a fire and result in an
increase of the intensity and size of the fire.
Fixed fire suppression systems also offer two advantages over
portable fire extinguishers: fast attack and application of the
suppressant to difficult-to-reach areas where fires may occur. In
addition, an automatic fire suppression system has the advantage of
detecting and suppressing fires without a person in attendance. Because
permanent underground diesel fuel storage facilities will not always be
attended, it is necessary to require a means of electrically or
mechanically detecting a fire as well as electrically or mechanically
activating the fire suppression system upon fire detection. This is
important since the potential hazard for mine personnel throughout the
mine is significant if a fire in a diesel fuel storage facility could
burn unnoticed.
The proposed rule would have established requirements for fire
suppression devices for permanent underground diesel fuel storage areas
and stationary unattended diesel-powered equipment. Because
Sec. 75.1916(d) of the final rule requires all diesel-powered equipment
to be attended while operating, and because proposed requirements for
stationary unattended equipment have not been adopted in the final
rule, Sec. 75.1912 of the final rule has been modified to apply only to
permanent underground diesel fuel storage facilities.
A number of commenters to the proposal expressed concern with the
requirements for fire suppression systems at permanent underground
diesel fuel storage facilities. One commenter stated that since diesel
fuel is a Class II combustible liquid, a diesel fuel storage station
used and moved with a working section should be treated similar to a
lubricating oil or grease storage station. This commenter expressed the
view that requirements for limiting the quantity of diesel fuel in
temporary storage and requiring portable fire extinguisher protection
would be adequate safeguards. Another commenter expressed concern with
the ability of a dry compound to suppress a fire over a long enough
period of time to prevent re-ignition. This commenter stated that high
volumes of ventilating air in a mine can blow dry compound away from
the area it is attempting to protect before it can cool down a hot
surface created by a fire.
MSHA agrees with the commenter who stated that diesel fuel stored
on and moved with a section should be treated as a Class II combustible
liquid. The final rule addresses this comment by establishing the
allowance for one temporary underground diesel fuel storage area for
the short-term storage and dispensing of diesel fuel on each working
section, which can move as mining progresses. A temporary underground
diesel fuel storage area is defined under Sec. 75.1900 of the final
rule as an area of the mine provided for the short-term storage of
diesel fuel in a fuel transportation unit, which moves as mining
progresses. These temporary underground diesel fuel storage areas are
required to meet the requirements in Secs. 75.1902, 75.1903 and 75.1906
of the final rule. All other diesel fuel storage areas will be treated
as permanent storage facilities and must comply with all of the
requirements for such facilities. Permanent diesel fuel storage
facilities pose a higher risk of fire than oil and grease storage areas
because diesel fuel is generally stored in much greater quantities in
underground coal mines. In addition, diesel fuel has a lower flash
point than either lubricating oil or grease and can be more easily
ignited by a hot surface.
Although permanent diesel fuel storage facilities are provided with
ventilating air during normal operations, these facilities are required
under Sec. 75.1903(a)(2) of the final rule to be equipped with either a
self-closing door or a means for automatic enclosure upon actuation of
the fire suppression system. This feature should prevent any
ventilating air from affecting the suppressant agent.
An automatic fire suppression system uses a supplemental detection
device to provide an early warning of a fire. The fire detection
system, which is generally activated by either smoke or heat,
[[Page 55480]]
automatically sends a signal to the system for the discharge of
suppressant agent. Automatic fire suppression systems activate a
network of piping and nozzles to allow suppressant agent to be released
and distributed directly at a predetermined fire hazard.
Under the final rule, automatic fire detection and fire suppression
systems are required to provide fire suppression for all areas of a
permanent underground diesel fuel storage facility. The final rule also
requires that the system include audible and visual alarms to warn of
fires or system faults and automatic electrical system shutdown in the
event of a fire. In addition, the final rule requires all fire
suppression systems to be tested and maintained in accordance with
manufacturer's recommendations. Finally, the final rule establishes
certain recordkeeping requirements for fire suppression systems that
are found not to meet required specifications during inspection and
testing.
Paragraph (a) of this section of the final rule requires that a
fire suppression system required by Sec. 75.1903(a)(5) be an automatic
multipurpose dry chemical type (ABC) fire suppression system listed or
approved as an engineered dry chemical extinguishing system by a
nationally recognized independent testing laboratory and appropriate
for installation at a permanent underground diesel fuel storage
facility.
The proposed rule would have required an automatic multipurpose dry
powder type fire suppression system suitable for the intended
application and listed or approved by a nationally recognized
independent testing laboratory.
A commenter to the proposal stated that this paragraph should
require that ``an automatic fire suppression system suitable for the
intended application shall be installed to protect the entire area
inside the fire proof enclosure.'' This commenter believed that all of
the necessary requirements for fire suppression systems were already
addressed in existing part 75, and that it was unnecessary to identify
protected coverage components inside the storage facility if the entire
area is required to be protected. Another commenter stated that the
requirement in the proposal that the ``system be suitable for the
intended application'' was ambiguous and could be subject to different
interpretations. This commenter stated that the term ``suitable'' could
refer to a system that is suitable for a particular type of fire (class
B or combustible liquid fire) or it could mean that the system has a
sufficient capacity to extinguish a fire. This commenter also
recommended that the final rule specify the capacity of fire
suppression systems installed at permanent underground diesel fuel
storage facilities.
In response to commenters, MSHA evaluated whether the requirements
for fire suppression systems in existing Sec. 75.1107 should be
extended to apply to permanent underground diesel fuel storage
facilities, but has concluded that such an extension would not be
appropriate. The fire hazards that exist at permanent underground
diesel fuel storage facilities are different from those on electric-
powered equipment, due to the storage of large quantities of diesel
fuel in close proximity to ignition sources at these facilities.
Additionally, because existing Sec. 75.1107 makes specific reference to
electrical controls and components on electric-powered equipment, a
modification of the existing requirements by inserting the term
``permanent underground diesel fuel storage facility'' in the
regulatory language would result in an extremely confusing regulation.
Existing fire suppression requirements in part 75 have therefore not
been applied to permanent underground fuel storage facilities.
In response to commenters' suggestions, the final rule does not
adopt the phrase ``suitable for the intended application'' from the
proposal. Instead, the final rule includes the more specific language
``listed or approved as an engineered dry chemical extinguishing system
approved by a nationally recognized independent testing laboratory.''
This modification is intended to clarify that an automatic fire
suppression system installed at a permanent underground diesel fuel
storage facility must be listed or approved by a nationally recognized
independent testing laboratory specifically for a fixed engineered dry
chemical extinguishing system unit.
The capacity and suitability of fire suppression systems for
protecting against specific fire hazards are specified as part of the
listing or approval by the nationally recognized independent testing
laboratory. The listing or approval ensures that a fire suppression
system is properly designed for a particular type of fire protection
hazard by putting the system through a series of specific performance
tests. The system must also meet rigid design requirements in order to
gain listing or approval.
Fire suppression systems should be installed by a qualified
individual following the installation and maintenance instructions in
the system manufacturer's installation manual. The sizing of a fire
suppression system is dependent upon the number of nozzles needed to
adequately cover the entire area of a permanent underground diesel fuel
storage facility. The number of dry chemical canisters required will be
proportional to the amount of area that must be covered by the nozzles.
This information can be obtained from the installation manual that is
part of the listing or approval documentation. Other installation
considerations, such as proper location and guarding of nozzles and
other system components to prevent damage, are addressed in the
system's installation manual. In addition to the installation
requirements, the manual includes provisions for follow-up maintenance
and inspection procedures.
One commenter to the proposal recommended that the term ``dry
powder'' be deleted from paragraph (a) because this commenter believed
that there were many equally effective systems, such as foam/water
spray systems, available to protect against fire hazards. Another
commenter stated that the terms ``listed'' and ``approved'' were not
strong enough. This commenter stated that there was no way of verifying
whether a system had been ``listed'' or ``approved'' and recommended
that the term ``tested'' replace the term ``listed''.
Although dry chemical is the most commonly used type of suppressant
agent in the mining environment and is specifically referenced in
paragraph (a) of the final rule, paragraph (a)(1) of the final rule
allows for alternate types of fire suppression systems that are no less
effective. In addition, the requirement that a system be listed or
approved by a nationally recognized independent testing laboratory is
more stringent than using the term ``tested''. Under the final rule,
when a system is listed or approved by a nationally recognized
independent testing laboratory, it means that the system has met
performance and design requirements outlined in an industry standard in
a certain configuration and for a specific function. Also, if a system
has been listed or approved by a nationally recognized independent
testing laboratory, it means that the system has met other requirements
for inspection, maintenance, and quality control assurances.
Also modified in this paragraph from the proposal is the term
``chemical'' replacing the term ``powder'' and the addition of the
reference ``ABC'' for the three classes of fire. These modifications
were made in response to commenters' request for clarification and to
incorporate more appropriate terminology.
[[Page 55481]]
A multipurpose dry chemical type agent is the most commonly used
and successfully applied type of suppressant agent in fire suppression
systems in underground coal mines. This type of agent is specifically
designed to extinguish ABC class fires. A class A fire refers to a fire
of combustible solid materials such as paper, rubber, textiles, and
cloth, and would involve such items as hosing at a permanent
underground diesel fuel storage facility. A class B fire would include
diesel fuel. Class C fires involve electrical components and could
include such components as lights, pumps, and valves at permanent
underground diesel fuel storage facilities.
The term ``engineered'' was added to the final rule in response to
commenters' concerns regarding the adequacy of a fire suppression
system to address all of the fire hazards at a permanent underground
diesel fuel storage facility. An engineered fire suppression system
will ensure that all of the fire hazards are addressed since a
representative from a fire suppression system manufacturer will go to
the facility and evaluate all of the fire hazards. The evaluation by
the system manufacturer representative also includes determining the
appropriate coverage areas for the fire suppression system, the number
and size of dry chemical canisters, the length of piping, and the
number of nozzles.
The proposed rule would have allowed the use of inert or halogenate
gas suppressant agents in unoccupied and enclosed areas where the use
of such suppressants would not pose a toxic hazard. One commenter to
the proposal recommended that the use of inert or halogenate gas
suppressant agents be prohibited because they create a toxic hazard.
This requirement has not been included in the final rule because inert
or halogenated gas fire suppression systems are considered an alternate
type of fire suppression system that are addressed in paragraph (a)(1)
of this section of the final rule. The potential toxic hazard presented
by inert or halogenated gas suppressant agent will be evaluated by MSHA
on a case-by-case basis as an alternate type system. In addition,
typical inert gas agents such as halon 1211 and 1301 are no longer
being marketed due to their reported contribution to the ozone
depletion of the environment.
Paragraph (a)(1) of the final rule adopts the provision from the
proposal that alternate types of fire suppression systems be approved
in accordance with Sec. 75.1107-13 of this part. This paragraph of the
final rule is intended to allow the use of fire suppression systems
other than dry chemical systems, so long as they provide substantially
equivalent protection. Under the final rule, MSHA will evaluate
alternate types of fire suppression systems, such as foam/water
sprinkler-based systems, using the criteria set forth in existing
Sec. 75.1107-13.
One commenter to the proposal objected to this provision and stated
that only the manufacturer who designs and constructs these systems
will know the exact capabilities and limitations of the system. This
commenter also stated that this requirement would result in the
installation of inadequate fire suppression systems at permanent
underground diesel fuel storage facilities, because the requirements in
existing Sec. 75.1107-13 are applicable to fire suppression systems
installed on equipment.
Existing Sec. 75.1107-13 establishes criteria for the approval of
alternate fire suppression devices. Under Sec. 75.1107-13, the
appropriate MSHA district manager may approve any fire suppression
system or device which provides substantially equivalent protection to
what would be achieved through compliance with the standard.
The final rule does not intend to allow alternate types of fire
suppression systems that do not adequately address fire hazards at
permanent underground diesel fuel storage facilities. Instead, all
types of alternate fire suppression systems must be installed and
operated in strict accordance with the system manufacturer's
recommendations as specified in paragraph (a)(2) of this section of the
final rule. Any type of fire suppression system that is not designed
and constructed in accordance with industry standards for fire
protection will be unacceptable.
Paragraph (a)(2) of the final rule adopts the requirement from the
proposal that the suppression system be installed in accordance with
the manufacturer's specifications and the limitations of the nationally
recognized independent testing laboratory listing or approval. One
commenter to the proposal expressed the view that the term ``listing''
was not specific enough and recommended that the language ``independent
testing'' be added. As explained earlier, a listing or approval by a
nationally recognized independent testing laboratory is more stringent
than the use of the term ``testing''. This comment has therefore not
been adopted in the final rule.
This requirement ensures that the system is installed within the
limits defined by the listing or approval issued by the nationally
recognized independent testing laboratory and as specified by the fire
suppression system manufacturer. Since the system is performance-tested
to a specific standard and in certain configurations, it must be
installed within these parameters to be effective.
Paragraph (a)(3) adopts the requirement from the proposal that the
fire suppression system be installed in a protected location or guarded
to prevent physical damage from routine operations. Damage to any part
of the fire suppression system can result in a malfunction of the
entire system and in the system not responding to fire hazards. For
example, a rock fall can pinch a hose or crush a sensor and create
faults that can disable the entire system or a portion of the system.
One commenter stated that the proposed rule did not define what
protections were necessary on fire suppression systems and suggested
that the systems be fully protected from physical elements, including
rib and roof falls. This commenter further stated that this protection
is already provided for electrical circuit breakers under existing
Sec. 75.901, and that this type of protection is even more vital for
the protection of fire suppression systems.
This comment has not been adopted in the final rule because the
construction requirements for permanent underground diesel fuel storage
facilities at Secs. 75.1902 and 75.1903 ensure that fire suppression
systems will be protected from the general hazards of the mine
environment. The installation requirements in this paragraph ensure
that additional protection will be provided for specific system
components.
Paragraph (a)(4), like the proposal, requires that the suppressant
agent distribution tubing or piping be secured and protected against
damage, including pinching, crimping, stretching, abrasion, and
corrosion. No specific comments were received on this aspect of the
proposal. During the normal mining activity in and around a permanent
underground diesel fuel storage facility, a fire suppression system can
become damaged from collisions with mining equipment or from daily
mining operations. This requirement ensures that fire suppression
system components are kept in proper working order and that the entire
system remains ready to discharge fire suppressant to the entire area
of a permanent underground diesel fuel storage facility.
Paragraph (a)(5) adopts the requirement from the proposal that fire
suppression nozzles be protected against the entrance of foreign
materials.
[[Page 55482]]
No specific comments were received on this aspect of the proposal. The
nozzles used on multipurpose dry chemical fire suppression systems can
be as small as \1/8\ of an inch. If material such as mud, coal dust, or
rock dust enters the nozzle, it can prevent the chemical agent from
discharging entirely, or alter the pattern and coverage of fire
suppressant.
Paragraph (b) of this section of the final rule requires that the
fire suppression system provide automatic fire detection and automatic
suppression for all areas within a permanent underground diesel fuel
storage facility. The proposal would have required automatic fire
detection and fire suppression for fuel storage tanks, containers,
safety cans, pumps, electrical panels and control equipment in fuel
storage areas. The requirement in the final rule responds to
commenters'' recommendations that automatic fire detection and
suppression be provided for all areas within a permanent underground
diesel fuel storage facility enclosure.
Although the listing or approval generally describes certain areas
that may pose a fire hazard, it does not specifically identify which
hazards must be covered by fire suppression. Fire suppression coverage
for the entire area of a permanent underground diesel fuel storage
facility is necessary because of the potential fire hazard created by
numerous ignition and fuel sources. The proposed coverage of only
certain specific hazards within a diesel fuel storage facility would
have resulted in other potential hazards not being addressed. Under the
proposal, it would have been possible for a fire to begin in one area
of the facility that was not specifically covered by fire suppression.
Under these circumstances, a fire could be difficult to contain if
large quantities of leaked diesel fuel are present throughout the
facility. The final rule requires the entire area of a diesel fuel
storage facility to be covered because of the likely spread of a fire
if a diesel fuel leak develops.
Paragraph (c) of the final rule requires that audible and visual
alarms to warn of fire or system faults be provided at the protected
area and at a surface location which is continually monitored by a
person when personnel are underground. The final rule also requires
that, in the event of a fire, personnel be warned in accordance with
the provisions set forth in Sec. 75.1101-23. This requirement is
intended to provide a means for immediate notification of personnel in
the area of a permanent underground diesel fuel storage facility when
the fire suppression system detects a fire or identifies a problem with
the system. The audible and visual indication of fire detection is
important because it alerts personnel in and around the area of a
permanent underground diesel fuel storage facility that a fire exists
and that a chemical agent is being discharged. The requirement for
audible and visual indication of fault detection is established in
order to alert personnel working in and around diesel fuel storage
facilities that a problem exists with the fire detection system so that
the defect can be addressed.
The proposal would have required that audible and visual alarms to
warn of fire or system faults be provided at the protected area and at
a surface location which is always staffed when personnel are
underground who could be endangered by a fire. In addition, the
proposal would have required that a means also be provided for warning
all endangered personnel in the event of a fire.
Several commenters to the proposal expressed concern over this
requirement, stating that the requirement for visual and audible alarms
at a surface location would be impractical for many small operators
because it would result in operators maintaining a monitoring system to
detect fires. These commenters recommended that fire suppression
systems be examined regularly to determine system faults, and that
audible and visual alerts should only be required at locations where
miners are present. Another commenter stated that mines have become lax
in responding to fire warnings. One commenter recommended that a formal
procedure be established to warn personnel in the event of a fire, and
that this procedure should be submitted to MSHA for approval and be
included in the mine emergency fire fighting and evacuation plan and in
the miners'' annual refresher training. Other commenters stated that
the proposed phrase ``always staffed'' does not ensure that a qualified
or responsible person will be designated to alert mine personnel
underground in the event of a fire. One commenter suggested that the
language ``always staffed'' be changed to ``someone who is qualified.''
The continual monitoring by a person on the surface of fire
detection and fire suppression system faults is not a burdensome
requirement given the chance that a fire or system fault may otherwise
go unnoticed. The early warning of a fire at a permanent underground
diesel fuel storage facility is critical, due to the presence of
numerous ignition sources and large quantities of diesel fuel. If
communication is not available, fire fighting efforts can be hampered
and the fire can spread. Also, if a program is not instituted to warn
of a fire, personnel located in other areas of the mine can be put at
risk of being cut off from escape. In addition, faults in fire
suppression systems need to be identified and communicated to
maintenance personnel so that system defects can be corrected. If an
automatic fire suppression system is not functioning properly and a
fire breaks out, it could result in a serious hazard since the fire
would not be extinguished in its incipient stage. The inspection and
maintenance requirements for fire suppression systems specified under
the final rule should ensure the reliability of the system and minimize
the occurrence of false alarms.
The final rule responds to commenters by providing flexibility in
the method used to alert mine personnel that a fire exists at a
permanent underground diesel fuel storage facility. Under the final
rule, when a fire is detected, personnel are to be warned in accordance
with the provisions set forth in existing Sec. 75.1101-23. Section
75.1101-23 requires that each operator of an underground coal mine
adopt a program for the instruction of all miners in fire fighting and
evacuation. The program of instruction is submitted to the appropriate
MSHA district manager for approval on a mine-by-mine basis. By
including the requirement for early warning of fires at permanent
underground diesel fuel storage facility in Sec. 75.1101-23, the final
rule allows this important communication provision to be developed by
taking into consideration mine-specific conditions.
This section of the final rule also requires that a person be
assigned on the surface whose duties include receiving notification of
fire detection and alerting underground personnel that a fire has been
detected. The final rule does not specify any qualification or training
for the person designated on the surface. However, the instruction of
all mine personnel, including the designated person staffed at a
surface location, is a critical element of an early warning fire
response strategy and is the responsibility of the mine operator under
Sec. 75.1101-23.
Paragraph (d) of this section of the final rule requires that the
fire suppression system deenergize all power to the diesel fuel storage
facility when actuated except that required for automatic enclosure and
alarms. This requirement was added to the final rule in response to
commenters' concerns regarding reignition of fires caused by electrical
failures. As stated earlier, fire
[[Page 55483]]
suppression systems are designed to suppress fires in their incipient
stage. If the ignition source and fuel sources remain present after the
fire suppression system has been actuated, the fire can reignite.
Shutting off any unnecessary electrical power to the facility will
remove a potential ignition source and reduce the likelihood that the
fire will reignite.
The Ontario accident data for fires on diesel equipment supports
the need for shutting off ignition sources to prevent reignition. This
hazard is just as significant for diesel fuel storage facilities, since
potential electrical ignition sources are present with large quantities
of diesel fuel. The final rule is also consistent with existing
Sec. 75.1107-4, which requires that the electric power source to the
protected equipment be disconnected when the fire suppression system is
actuated.
This requirement also applies to any fuel transportation unit
located in a permanent diesel fuel storage facility that is equipped
with an electric panel and controls directly connected to an electrical
power source.
Paragraph (e) of the final rule, like the proposal, requires that
fire suppression systems at permanent underground diesel fuel storage
facilities be equipped with two manual actuators. The final rule
requires that at least one actuator be located within the fuel storage
facility and at least one actuator be located a safe distance away from
the facility in intake air, upwind of the storage facility. The final
rule is intended to ensure that at least two manual actuators be
provided in locations that are accessible to mine personnel working in
or around a permanent diesel fuel storage facility. This requirement is
similar to the fire extinguisher location requirements for underground
fuel storage facilities and areas in Sec. 75.1903(b)(1) and (b)(2) of
the final rule, which provide that at least one portable fire
extinguisher be located outside of the storage facility or area upwind
of the facility, in intake air, to enable miners to reach the actuator
in the event of fire. To allow flexibility in complying with the
requirements of this paragraph, what constitutes a ``safe distance from
the facility'' has not been specified in the final rule. The location
of the actuator outside the facility should be determined based on mine
conditions and the particular usage of the facility.
Commenters generally expressed support for this aspect of the
proposal. One commenter recommended that a requirement be added to
address manual application of water in lieu of manual actuators when
sprinkler systems are used. Another commenter suggested that actuators
be separated from each other, and specifically recommended that a check
valve be used to ensure that one faulty actuator does not circumvent or
defeat the use of the other actuator.
The final rule specifically addresses only requirements for dry
chemical fire suppression systems, and a water sprinkler type fire
suppression system would be considered an alternate type of fire
suppression system under paragraph (a)(1) of this section. As a result,
the final rule does not adopt the suggestion that an additional
requirement be added to address manual application when water sprinkler
systems are used. In addition, the final rule does not include a
requirement for a check valve between the actuators for fire
suppression systems. This is considered part of the system design and
is more appropriately addressed by the system manufacturer and the
listing or approving nationally recognized independent testing
laboratory.
Paragraph (f) of the final rule adopts the requirement from the
proposal that the fire suppression system remain operational in the
event of an electrical system failure. No specific comments were
received on this aspect of the proposal. This requirement is intended
to ensure that the system will be functional if power from external
sources is lost. The phrase ``engine shutdown'' has not been adopted
from the proposal, because the phrase would have applied to fire
suppression system requirements for unattended diesel- powered
equipment. Because the final rule does not permit the operation of
unattended diesel-powered equipment, this phrase is no longer
necessary.
Paragraph (g) adopts the requirement from the proposal that
electrically operated detection and actuation circuits be monitored and
provided with status indicators showing power and circuit continuity.
The final rule also requires that automatic detection systems be
provided with a means to indicate the functional readiness status of
the detection system. This paragraph requires that the fire suppression
system provide a means of notifying miners and maintenance personnel of
the functional readiness status of both the detection and actuation
circuit and the power source. This paragraph also requires that
automatic systems not electrically operated provide a means of
notifying the operator or maintenance person of the functional
readiness of the system.
This requirement is included in the final rule to ensure the
continuity of electrical systems used to detect faults on fire
suppression systems. This requirement will serve to alert miners and
maintenance personnel when a fire suppression system is not in a state
of readiness due to an electrical system fault. The continuity of the
electrical system used to detect fires and actuate the system is
important since an automatic system is based on early detection and
automatic actuation.
One commenter to the proposal stated that the fire suppression
system should also be protected as specified in Sec. 75.1101-17, which
requires that each dry powder chemical system be adequately sealed to
protect all components of the system from moisture, dust, and dirt.
The protection of the fire suppression system components from
moisture and dust is adequately addressed by the requirements of
paragraphs (a)(3), (a)(4) and (a)(5) of this section of the final rule.
In addition, the listing or approval typically includes requirements
for a dust shield and checks of the powder for dryness.
Paragraph (h) of the final rule adopts the requirement from the
proposed rule that each fire suppression system be tested and
maintained in accordance with the manufacturer's recommended inspection
and maintenance program and as required by the nationally recognized
independent testing laboratory listing or approval, and be visually
inspected at least once each week by a person trained to make such
inspections.
The proposed rule would have required each fire suppression device
to be visually inspected at least once each week by a person qualified
to make such inspections. The proposal also would have required that
each fire detection device be tested and maintained in accordance with
applicable requirements in Sec. 75.1100.
Commenters to the proposal generally expressed support for
maintenance of fire suppression systems installed at permanent
underground diesel fuel storage facilities. A number of commenters,
however, recommended that a maintenance program specifically designed
for fire suppression systems be developed at each mine. One commenter
to the proposal expressed concern over the requirement for weekly
visual inspections of fire suppression systems at permanent underground
diesel fuel storage facilities. This commenter recommended that there
be frequent functional testing of the suppression systems to ensure
that lines are not blocked or pinched. Another commenter stated that
the proposal did not specify the types of tests that should be
conducted on fire suppression systems at permanent underground
[[Page 55484]]
diesel fuel storage facilities. Other commenters expressed concern over
the frequency of tests and inspections. These commenters recommended
that detailed inspections and functional tests be conducted
semiannually or quarterly. One commenter recommended that fire
suppression systems be treated in the same manner as portable fire
extinguishers and that inspections be conducted once a week and
physically tested twice a year.
Under the final rule, the weekly visual inspection is not intended
to be an in-depth examination. The weekly visual inspection is intended
to be a quick check to verify that there are no obvious defects, such
as disconnected hose lines or altered nozzles. An in-depth inspection
takes place as part of the manufacturer's recommended testing and
inspection procedure also required under the final rule. Fire
suppression system manufacturers are most familiar with the design and
operation of their systems and are best able to identify the components
that need maintenance, the type of maintenance needed, and the
frequency of maintenance. Adequate maintenance is essential because of
the importance of these systems in fire protection. The maintenance and
testing requirements for fire suppression systems are in addition to
the requirement set forth for a weekly visual inspection.
The manufacturer's inspection and maintenance procedures are
spelled out in great detail in the manufacturer's manual and include
the recommended inspection intervals, which depend on the environment
in which the system operates. In addition, these inspection and
maintenance procedures are evaluated as part of the system's approval
or listing by a nationally recognized independent testing laboratory.
This paragraph is identical to the requirement in Sec. 75.1107-
16(a). As stated earlier, the fire suppression system requirements in
Secs. 75.1107-3 through 75.1107-16 cannot be directly applied to diesel
equipment because the fire hazards presented by diesel fuel are
different from those on electric-powered equipment, due to the close
proximity of large quantities of diesel fuel to potential ignition
sources.
Also modified in this paragraph is the replacement of the term
``device'' with the term ``system''. This was done because MSHA intends
that the whole system be inspected, not just individual components of a
system.
A person ``trained'' to perform the inspections and tests required
by paragraph (h) of this section of the final rule is not required to
be a qualified person under Sec. 75.1915. However, the final rule
intends that the person performing tests and inspections of fire
suppression systems have sufficient knowledge to determine whether a
fire suppression system is functioning properly. MSHA anticipates that
since fire suppression systems are common to both electric and diesel
equipment, the mine operator will work with either the fire suppression
system manufacturer or distributor to ensure that persons responsible
for the maintenance of fire suppression systems are adequately trained.
Paragraph (i) of the final rule establishes recordkeeping
requirements for the inspection and maintenance requirements for fire
suppression systems set forth in paragraph (h), and requires that
persons performing inspections and tests of these systems record
results of tests and inspections only when a system does not meet the
installation or maintenance requirements of this section. Under these
circumstances, the person performing the inspection or test is required
to indicate the fuel storage facility where the fire suppression system
did not meet the installation or maintenance requirements of this
section, the defect found, and the corrective action taken. The final
rule also requires that these records be kept either manually or
electronically in a secured manner that is not susceptible to
alteration. In addition, the final rule requires that records be
maintained at a surface location at the mine for one year and made
available for inspection by an authorized representative of the
Secretary and by miners representatives.
The proposal would have required that a record be kept of all of
the inspections of fire suppression systems and maintained at an
appropriate location for each fire suppression device. One commenter to
the proposal recommended that the records required by this section be
made available to all interested parties and that this information be
centrally located on the surface of the specific mine.
Office of Management and Budget guidance comments directed MSHA to
reexamine the recordkeeping requirements in the proposal and
recommended that the final rule require paperwork that was the least
burdensome necessary. MSHA has done so, and the final rule does not
adopt the proposal that all fire suppression system test and
maintenance results be recorded. In response to commenters and
consistent with other provisions of the final rule, paragraph (i)
requires that records of inspections and tests be made only when a fire
suppression system does not meet the installation or maintenance
requirements of this section. This requirement is important because if
a fire suppression system does not meet its listing or approval, the
defect can be of a nature and seriousness that the system can fail when
a fire begins. This requirement is intended to ensure that records are
maintained and made available to interested parties when a defect is
found, and that the appropriate level of mine management is made aware
of defects requiring attention.
The final rule does not specify a particular way of recording the
test and maintenance data, only that it be located at the surface of
the mine. The records of the inspections and tests must be made in a
secure media not susceptible to alteration. A detailed discussion of
the subject of acceptable record books and electronic records can be
found under the heading ``Recordkeeping Requirements'' in the General
Discussion section of this preamble.
The final rule does not adopt the requirement from the proposed
rule that records of inspections be maintained at an appropriate
location near each fire suppression system. Instead, paragraph (i)(3)
of this section of the final rule establishes the requirement
recommended by a commenter that records of inspections and tests be
maintained at a surface location at the mine. Storing records on the
surface at the mine makes them more accessible to interested parties.
Also in response to commenters, the final rule provides access not only
to miners representatives but to authorized representatives of the
Secretary. This provision ensures that test and inspections of fire
suppression systems are being made and, when a defect is found,
corrective action is taken.
Paragraph (j) adopts the proposed requirement that all miners
normally assigned in the active workings of the mine be instructed
about the hazards inherent to the operation of fire suppression
systems, and where appropriate, the safeguards available for each
system. This requirement is intended to ensure that all miners working
in areas where fire suppression systems operate are instructed in any
inherent hazards and necessary precautions associated with the
operation of these systems. The final rule modifies the proposal in
that the term ``device'' has been replaced by the term ``system'' to
clarify that this requirement applies to the entire system rather than
to system components.
One commenter to the proposal agreed with the requirement that
miners be trained in the hazards and safeguards
[[Page 55485]]
of fire suppression systems, but recommended that such training be
incorporated in the annual refresher training required under existing
Sec. 75.1101-23 for the program of instruction, location and use of
fire fighting equipment. Under the final rule, it is anticipated that
the instruction on the hazards of fire suppression systems required by
this paragraph will be part of the Sec. 75.1101-23 instruction.
Section 75.1913--Starting Aids
This section addresses the storage and use of volatile fuel
starting aids for diesel-powered equipment. The requirements of the
final rule are similar to the requirements contained in the proposal,
with some minor modifications. This section places limitations on the
use and storage of volatile fuel starting aids underground, to minimize
the risks of fire or explosion. Under the final rule, volatile fuel
starting aids must be used in accordance with recommendations of the
starting aid manufacturer, the engine manufacturer, and the machine
manufacturer. The final rule also includes requirements for the storage
of volatile fuel starting aids, and prohibits the use of starting aids
under certain circumstances, such as in areas where permissible
equipment is required or where 1.0 percent or greater concentration of
methane is present. Connection of compressed oxygen or compressed
flammable gases to diesel air-start systems is also prohibited.
The Diesel Advisory Committee recognized that improper storage and
handling of starting aids could present fire and explosion hazards in
underground coal mines. The Committee therefore recommended that MSHA
regulate the storage and use of starting aids. The proposed rule set
forth limitations on the use of starting aids, to minimize the hazards
associated with their use in the underground coal mine environment. The
requirements of the final rule reflect MSHA's determination that
volatile fuel starting aids can be safely used underground if
appropriate precautions are taken.
Volatile fuel starting aids, normally ethyl ether, facilitate the
starting of diesel engines in cold temperatures. In very cold weather
the compression ignition of diesel engines cannot easily reach the high
temperature necessary to ignite diesel fuel. This makes it difficult,
and in some cases impossible, to start the engine without special
measures, such as the use of volatile fuel starting aids. Volatile fuel
starting aids sprayed into a cold diesel engine help to start the
engine because they ignite at a much lower temperature than diesel
fuel. Starting aids that are ignited in a diesel engine will both heat
up the cylinder walls of the engine and start the engine spinning,
resulting in easier ignition of the diesel fuel.
The use and storage of volatile fuel starting aids in underground
coal mines present safety hazards, due to the starting aids' high
volatility. When these substances are stored or used improperly, they
can present a very real danger of fire or explosion, particularly in
the underground coal mine environment.
Commenters were divided on whether the use of starting aids should
be permitted in underground coal mines. Some commenters recommended a
complete prohibition of the use of volatile fuel starting aids
underground, stating that starting aids are extremely flammable, have a
very low flash point, and can be ignited by any source of heat in the
mine. These commenters believed that there were already numerous
potentials for fire in the underground coal mine environment, and that
permitting the use of starting aids would introduce another unnecessary
hazard into that environment. Some commenters believed that starting
aids were used at some mines as a substitute for effective maintenance
of diesel engines, and that a properly maintained engine should be able
to start on its own, without the boost that a starting aid provides.
Other commenters advocated allowing the use of starting aids but
strictly controlling their use. Several commenters stated that starting
aids were currently being used safely and effectively in their mines,
and that any hazards arising from their use could be controlled by
careful handling. These commenters stated that proper maintenance of
diesel engines does not prevent starting difficulties in cold
temperatures. One commenter observed that air temperatures at mines
located at elevations of 9,000 or 10,000 feet can fall well below
0 deg. F. Several commenters observed that a diesel-powered machine
that has been shut down and has been sitting in cold weather, such as
over a weekend, can be virtually impossible to start without the use of
a starting aid.
Some of the commenters who favored prohibiting the use of volatile
fuel starting aids underground stated that starting aids sometimes were
used as a substitute for effective maintenance. Although an engine that
has not been properly maintained could in some cases be started more
easily with starting aids, this fact alone does not compel the
prohibition of volatile fuel starting aids in underground coal mines.
The final rule requires regular maintenance and testing of diesel-
powered equipment, designed to ensure that the equipment is kept in
good operating condition. Compliance with these requirements should
eliminate any need to use starting aids as a replacement for effective
equipment maintenance.
Paragraph (a) of this section requires that volatile fuel starting
aids be used in accordance with the recommendations of the starting aid
manufacturer, the engine manufacturer, and the machine manufacturer.
The proposed rule would have required that volatile fuel starting aids
be used in accordance with the specific recommendations in the engine
manufacturer's maintenance and operations manual.
Several commenters noted that the written documentation from
machine or engine manufacturers does not always address correct use of
volatile fuel starting aids, and expressed their concern that starting
aids could create serious hazards if not used in conformance with
specific recommendations. In response to these comments, the final rule
provides that starting aids must also be used in accordance with the
recommendations of the starting aid manufacturer, ensuring that mine
operators will at a minimum be guided by those instructions. Starting
aid manufacturers are already required by Occupational Safety and
Health Administration regulations to develop Material Safety Data
Sheets (MSDS) for their products. To comply with this provision the
mine operator should obtain an MSDS and any other product safety and
use information prepared by the starting aid manufacturer on the safe
use of that particular starting aid, and use the starting aid in
accordance with those instructions.
Because engine and machine manufacturers are in the best position
to determine whether volatile fuel starting aids can be safely and
effectively used with a particular engine or machine, the final rule
also requires mine operators to use starting aids in accordance with
any available recommendations from the engine and machine manufacturers
on the safe use of starting aids. This requirement recognizes that
volatile fuel starting aids can damage engine or machine components and
result in the failure of machine safety devices or increase exhaust
emissions. For example, a buildup of the starting aid in intake or
exhaust components could result in an explosion. Use of starting aids
in accordance with the recommendations of engine and machine
manufacturers will minimize
[[Page 55486]]
any safety hazards and avoid damage to the engine or machine, such as
damage to intake or exhaust components, especially on permissible
equipment.
Although the final rule is not intended to prohibit the use of
starting aids if such information has not been developed by the machine
or engine manufacturer, MSHA encourages diesel-powered engine and
machine manufacturers who do not already do so to develop
recommendations on the use of volatile fuel starting aids with the
engines and machines they produce.
Paragraph (b) requires that containers of volatile fuel starting
aids be conspicuously marked to indicate their contents. This paragraph
further requires that containers of volatile fuel starting aids that
are not in use be stored in metal enclosures that are used only to
store starting aids. The metal enclosures themselves are required to be
conspicuously marked, secured, and protected from damage.
The requirement that starting aid containers be conspicuously
marked was not included in the proposal, but has been incorporated in
the final rule in response to commenters' concerns over the serious
dangers that could result if starting aids containers were damaged in
any way. The container marking requirement is intended to prevent
inadvertent damage to containers by ensuring that mine personnel are
aware of the containers' contents. Labels that are affixed to the
starting aid can by the starting aid manufacturer will satisfy the
requirement for container marking.
The final rule also requires that enclosures for containers of
starting aids be made of metal, marked, secured, and protected from
damage, and used only for the storage of starting aids. The proposed
rule would have required only that starting aids be stored in a fire
proof enclosure when not in use. The final rule includes additional
requirements to address commenters' concerns that starting aid
containers could be inadvertently damaged, resulting in the
unintentional release of the highly flammable starting aid. These
additional requirements are similar to the requirements in the final
rule that apply to safety cans containing diesel fuel that are
transported on vehicles. Because both volatile fuel starting aids and
diesel fuel present a possible fire hazard, the final rule imposes
similar precautions for the handling and storage of these substances.
The final rule also prohibits any other items, such as tools, from
being stored with volatile fuel starting aids. This prohibition
responds to commenters' concerns that containers of volatile fuel
starting aids could be damaged through contact with other items,
resulting in the release of the starting aid and the creation of a
potentially hazardous situation.
Some commenters noted that the term ``fire proof enclosure'' used
in the proposed rule was not defined anywhere in the regulations, and
recommended the substitution of the term ``noncombustible''. Other
commenters opposed the use of the term ``noncombustible'' because of
their concern that a container that is simply noncombustible may not be
substantial enough to protect starting aid containers. MSHA agrees with
commenters who believe that the term ``fire proof'' is ambiguous, and
also with commenters who oppose the substitution of the term
``noncombustible'' for the term ``fire proof'' because containers that
are ``noncombustible'' may not be sufficiently durable. The final rule
therefore requires that containers of starting aids be stored when not
in use in metal enclosures, which are not only noncombustible but also
sturdy enough to protect the starting aid containers that are stored
there.
Paragraph (c) adopts the requirements of the proposal, and imposes
specific restrictions on where and under what circumstances volatile
fuel starting aids may be used in underground coal mines, to minimize
any hazards presented by their use. Paragraph (c)(1) prohibits volatile
fuel starting aids from being taken into or used in areas where
permissible equipment is required. Volatile fuel starting aids can
create flames that flame arresters, which are designed to provide
protection against methane ignitions, cannot stop. Use of volatile fuel
starting aids in an area where permissible equipment is required could
lead to an ignition of any methane in the area. Use of starting aids in
those areas is therefore forbidden in the final rule.
Paragraph (c)(2) prohibits the use of volatile fuel starting aids
in the presence of open flames or burning flame safety lamps, or when
welding or cutting is taking place. As noted by several commenters,
vapors from volatile fuel starting aids are easily ignited. The final
rule requires that volatile starting aids be kept away from the
potential ignition sources of open flames or welding or cutting.
Starting aids are also prohibited in the presence of burning flame
safety lamps. The gauze in a flame safety lamp, although safe for use
in the presence of methane, will not prevent the propagation of the
flame by the ether vapors given off by the starting aid. The final rule
is intended to prohibit these ignition sources in the immediate
vicinity of any area where volatile fuel starting aids are being used.
Paragraph (c)(3) adopts the proposal to prohibit the use of
volatile fuel starting aids in any area of the mine where 1.0 percent
or greater concentration of methane is present. This requirement
minimizes the possibility that starting aid vapors that have
accidentally been ignited would spread to methane in the surrounding
area. Permissible equipment may not prevent a flashback of fire that
could ignite a methane atmosphere.
The proposed rule would have prohibited the use of starting aids in
areas of the mine where 1.0 percent or greater of methane is detected.
The final rule has been clarified to reflect that volatile fuel
starting aids must not be used where 1.0 percent or greater of methane
is ``present'', thereby placing on the mine operator the responsibility
of ensuring that methane levels are within acceptable limits before
volatile fuel starting aids are used.
Paragraph (d) imposes limitations on the use of compressed gases as
starting aids for diesel-powered engines. The final rule adopts the
proposal's prohibition of the connection of compressed oxygen or
compressed flammable gases to diesel air-start systems. Commenters
generally supported this restriction. The use of compressed oxygen in
the presence of engine lubricants, which are normally in diesel air
start-systems, presents an immediate danger of a fire. The final rule
consequently forbids the use of compressed oxygen for this purpose.
Additionally, the introduction of compressed flammable gases into the
machine's compressed air system presents not only the same fire hazard
as compressed oxygen, but also a danger of explosion from flammable
gases being placed in close proximity to possible sparks from the
diesel engine. The final rule therefore also prohibits the use of
compressed flammable gases in diesel air-start systems. Nonflammable
gases, such as nitrogen, are permitted for this purpose.
Section 75.1914 Maintenance Of Diesel-Powered Equipment
Section 75.1914 sets forth maintenance, repair and testing
requirements for diesel-powered equipment, and also indicates the level
of training or qualification a person must have to perform these
important tasks. The rule generally requires that diesel-powered
equipment be maintained in safe and approved condition, and
specifically requires weekly equipment examination, weekly testing and
evaluation of gaseous
[[Page 55487]]
emissions, flushing and draining of scrubbers, and changing of air
filters. A person must be qualified under Sec. 75.1915 to perform
maintenance and repairs of approved and other specified features on
diesel-powered equipment, and to conduct weekly equipment tests and
examinations. However, the rule allows other functions required under
this section to be performed by a person not qualified under
Sec. 75.1915, so long as the person has been trained in the task.
This section of the final rule recognizes that effective equipment
maintenance is an indispensable element in reducing the health and
safety hazards of diesel-powered equipment, and that adequate training
of maintenance personnel is an important part of ensuring that such
work is performed correctly. The purpose of the requirements of this
section is to ensure that diesel-powered equipment is properly
maintained so that it does not deteriorate through neglect, abuse, or
normal use and result in a safety or health hazard to miners.
Virtually all commenters to the proposed rule supported the need
for maintenance requirements for diesel-powered equipment used in
underground coal mines. Commenters agreed that regular maintenance and
routine examination of equipment is essential, as the performance of
even the best-designed equipment will decline over time without proper
maintenance. Inadequate maintenance of diesel equipment can result in
the creation of fire or explosion hazards, and the levels of harmful
gaseous and particulate components in diesel exhaust can increase when
equipment is poorly maintained.
Several commenters to the proposed rule provided specific examples
of the problems and hazards that result when maintenance personnel are
poorly trained. Some commenters stated that inadequately trained
personnel frequently failed to maintain diesel equipment in approved
condition, causing the engines to deteriorate and resulting in
increased levels of harmful exhaust gases. Commenters also reported
that untrained persons were more likely than properly trained persons
not only to allow safety systems to malfunction in the first place, but
also to bypass the malfunctioning safety system in order to continue
operating the machine, rather than to repair the system.
Paragraph (a) of this section retains the language of the proposed
rule and requires that all diesel-powered equipment used in underground
coal mines be maintained in approved and safe condition or removed from
service. Several commenters recommended that the word ``approved'' be
deleted, in the belief that it would be acceptable to use permissible
equipment in non-approved condition when the machine was being operated
in an outby location.
Paragraph (a) of the final rule prohibits the use of diesel
equipment that is not in approved and safe condition. This prohibition
includes the operation of permissible diesel-powered equipment in outby
areas when an approved feature has been disabled. There are several
reasons that this requirement has been adopted in the final rule. Many
types of approved diesel equipment are extremely mobile, moving easily
from areas of the mine where permissible equipment is required to areas
where it is not, and there is nothing to distinguish a piece of diesel-
powered equipment that has not been maintained in permissible condition
from one that has. Both bear MSHA approval plates. Additionally,
temperature sensors and other safety system components on diesel-
powered equipment can be permanently damaged by exposure to high
temperature exhaust gas when the equipment is not maintained in
approved condition and a safety system is bypassed. The final rule
therefore requires that equipment be maintained not only in safe
condition but also in approved condition.
Paragraph (b) requires that maintenance and repairs of approved
features, and the features required by Secs. 75.1909 and 75.1910, be
made only by a person qualified under Sec. 75.1915. The final rule
retains the concept of the proposal that the maintenance and repair of
certain features of diesel-powered equipment be performed by a
qualified person. The majority of commenters supported mandatory
training and some form of qualification for those individuals
performing these functions because it would help to ensure that diesel
equipment is adequately maintained and kept in good operating
condition. The Diesel Advisory Committee also recommended that
qualified persons be responsible for the more complicated systems on
the machine, such as the approved components.
A more extensive level of training is needed to ensure that persons
working on more complex equipment features are adequately skilled.
Additionally, MSHA machine approval requirements are largely
performance-oriented, and equipment manufacturers consequently have
significant latitude in designing their equipment to satisfy MSHA's
permissibility requirements. Because a variety of equipment designs
could accomplish the safety objectives mandated by an MSHA approval,
approved equipment does not always conform to easily recognizable
standards, and the ability to perform maintenance and repair work on
the more complex features of diesel-powered equipment requires a
comprehensive understanding of the equipment's design. The final rule
therefore adopts the requirement of the proposal that persons
performing work on certain specified features of diesel-powered
equipment be qualified under Sec. 75.1915, which requires completion of
a training program developed by the mine operator.
The proposed rule specified only that ``approved features'' must be
maintained and repaired by a person qualified under Sec. 75.1915, and
did not include within its scope ``features required by Secs. 75.1909
and 75.1910'' as does paragraph (b) of the final rule. However, the
scope of this requirement under the final rule is essentially the same
as it would have been under the proposed rule. Under the proposed rule,
all nonpermissible equipment, with the exception of a limited class of
light-duty equipment and stationary unattended equipment, would have
been subject to a whole machine approval under part 7. Because the
final rule does not require whole machine approval of nonpermissible
equipment, and instead requires that this equipment be provided with
the safety features set forth in Secs. 75.1909 and 75.1910, essentially
the same features must be maintained and repaired by a qualified person
under the final rule as would have been required under the proposal.
Paragraph (c) of the final rule requires that the water scrubber
system on diesel-powered equipment be drained and flushed, by a person
who is trained to perform this task, at least once during each shift
that the equipment is operated. The proposed rule contained the same
requirement for flushing scrubbers, but did not specify what type of
training was required for the person performing the task.
The rationale behind the requirement for flushing and draining is
that routine cleaning of scrubbers, which cool equipment exhaust gases
and act as flame arresters, is essential to prevent a buildup of solid
exhaust particles and sludge in the scrubber. This condition can
eventually block internal passages of the scrubber, impairing the
scrubber's effectiveness and compromising safety in the mine. The
Advisory Committee also recommended that MSHA require mine operators to
change scrubber water on a regular basis.
Commenters generally supported regular draining and flushing of
[[Page 55488]]
scrubber systems, although some commenters questioned whether the rule
should specify the point in the shift when draining and flushing must
be done. Commenters also questioned what level of qualification was
necessary as a prerequisite to performing this task. The consensus of
the Advisory Committee was that routine maintenance, such as changing
scrubber water, could be performed by a person who is not certified,
and that task training would be sufficient in those situations.
MSHA agrees that draining and flushing of the scrubber is a
relatively straightforward task, and that the comprehensive training
required for qualification under Sec. 75.1915 is unnecessary to ensure
that persons perform this task competently. The final rule therefore
clarifies MSHA's intention that scrubber draining and flushing need not
be done by a person qualified under Sec. 75.1915, only that the person
be trained to perform the task. MSHA expects that the draining and
flushing of the water scrubber system will typically be performed by
the machine operator.
In response to the proposed requirements for scrubber maintenance,
some commenters stated that the final rule should specify that scrubber
systems must be drained and flushed at the beginning of the shift.
These commenters were concerned that if the rule did not specifically
require draining and flushing at the beginning of the shift, MSHA could
not issue a citation for violation of this standard until the end of
the shift, making enforcement difficult. Other commenters advocated
that the final rule require the scrubber system to be drained and
flushed at the end of the shift, allowing mine operators to perform the
task as part of the routine maintenance to prepare the machine for the
next shift.
MSHA has carefully considered the comments on this issue, and has
chosen to retain the language of the proposed rule in the final rule,
which simply requires scrubber systems to be flushed and drained once
during each shift that the equipment is operated, without specifying
when during the shift the task must be performed. This is consistent
with MSHA's intention to afford mine operators reasonable flexibility
in performing the maintenance required by the final rule. However, MSHA
recommends that mine operators perform scrubber maintenance at about
the same point during every shift, thereby ensuring that scrubbers are
flushed and drained every 8 to 10 hours (depending on the length of the
shift) during the equipment's operation.
Paragraph (d) requires that the intake air filter be replaced or
serviced either when the intake air pressure drop device indicates that
it is necessary, or when the engine manufacturer's maximum allowable
air pressure drop level is exceeded. The final rule also requires that
this replacement or servicing be done by a person who is trained to
perform the task.
Maintenance of diesel machine air filters is an important element
of overall equipment maintenance. Air filters screen the air taken in
by the machine for combustion. Over time, the filters load up with dust
and dirt, restricting air flow and making the engine work harder to
pull in the same amount of air. As the engine works harder, greater
quantities of engine emissions are produced, adversely affecting the
quality of the air that miners breathe. Research and experience
indicate that air restrictions have a negative effect on emission
generation, specifically carbon monoxide and diesel particulate.
The proposed rule would have required filter replacement or
servicing when the filter was ``dirty'' as well as when the machine's
intake air pressure drop device indicated that it was necessary. The
proposed rule would not have required, as does the final rule, filter
maintenance when the manufacturer's maximum allowable air pressure drop
level is exceeded.
Commenters generally supported the requirements of this paragraph,
and several stated that dirty air filters were frequently to blame when
engines began to produce increased levels of carbon monoxide. However,
several commenters objected to mandatory filter replacement and
servicing when the filter was ``dirty'', pointing out that the term
``when dirty'' was ambiguous. Commenters stated that air filters catch
dirt continually, and are therefore ``dirty'' to some degree at all
times. MSHA agrees with commenters on this issue, and has concluded
that the use of the term ``when dirty'' could create uncertainty for
mine operators in complying with the provision. The requirement that
filters be replaced or serviced ``when dirty'' has therefore not been
adopted in the final rule.
The final rule does adopt the requirement of the proposed rule that
air filters be replaced or serviced when the intake air pressure device
indicates that it is necessary. Intake air pressure devices monitor the
air pressure across the filter. As the air filter loads up with dust
and dirt the pressure drop across the filter will increase, and at a
certain point the intake air pressure device will signal that the
filter is sufficiently blocked by dirt to require servicing or
replacement.
Not all types of diesel-powered equipment are presently equipped
with intake air pressure devices. Under the proposed rule, air filters
without air pressure devices would have been required to be changed or
serviced ``when dirty''. However, as discussed above, that provision
has not been included in the final rule. One commenter to the proposed
rule stated that service indicators specified by the manufacturer are
sufficient for determining when an air filter should be changed. A
service indicator is simply the manufacturer's specification of the
drop in pressure across the air filter, reflected by the air pressure
gauge on the machine, indicating that the air filter must be serviced
or replaced. MSHA agrees that service indicators provide an objective
and measurable method of determining the need for air filter servicing
for machines without intake air pressure devices. The final rule has
therefore been modified to provide that air filters must be replaced or
serviced when the engine manufacturer's maximum allowable air pressure
drop level is exceeded.
The proposal did not specify the level of training or qualification
required for the person performing air filter maintenance under this
paragraph, and commenters questioned whether MSHA intended that this
task be performed by a person qualified under Sec. 75.1915. Commenters
generally stated that air filter maintenance did not need to be
conducted by a qualified person, only by someone who has been trained
to perform the task. This view is consistent with the consensus of the
Advisory Committee that simple maintenance activities, such as changing
air filters, could be performed by miners who are not qualified or
certified. Accordingly, the final rule specifies that air filter
maintenance must be performed by a person who has received training in
the task.
Paragraph (e) requires that mobile diesel-powered equipment that is
to be used during a shift be visually examined by the equipment
operator before being placed in operation, and that equipment defects
that affect safety be reported to the mine operator. This requirement
is identical to that of the proposed rule, and was supported by
commenters.
MSHA intends that the examinations required under this paragraph
consist of the equipment operator conducting a check of the equipment
before operating it to verify that the machine has no obvious safety
defects, such as fuel leaks, loose batteries, or accumulations of
combustible materials on the
[[Page 55489]]
machine. The language of the final rule has been changed slightly to
require that the equipment be ``visually examined'' rather than
``inspected'', to better convey the nature of the examination. Such an
examination will provide a regular check on some of the more
conspicuous equipment problems. This paragraph also requires that
observed defects be reported promptly to the mine operator, which could
be a responsible management official, such as a superintendent or
foreman. The word ``promptly'' has been included in the final rule to
clarify that safety defects observed during this check should be
directed to a responsible management official in a timely manner.
Paragraph (f) provides that all diesel-powered equipment must be
examined and tested weekly by a person qualified under Sec. 75.1915.
Commenters generally agreed with the concept of mandatory equipment
examination at regular intervals, although several commenters stated
that only diesel equipment that was in use should be subject to
required examinations, advocating revision of the rule to reflect that
only equipment ``in service'' is subject to weekly examination.
Although MSHA understands the basis for these commenters' concerns,
MSHA has concluded that inserting the term ``in service'' in the final
rule could be misinterpreted by some mine operators to exclude
equipment from the weekly examination requirement that the Agency does
not intend to exclude. For example, some operators may consider
equipment to be out of service if it has not been operated for an
extended period, even though the equipment remains in the mine and
could be operated at any time. MSHA takes a very broad view of what
equipment is ``in service,'' regarding all equipment not located in
maintenance shops or surface storage areas as being ``in service'' and
subject to weekly examination and testing. MSHA has therefore not
adopted the change advocated by commenters.
Although commenters supported the concept of regular examination
and testing of diesel-powered equipment, there was no clear consensus
on how regularly equipment must be examined. A few commenters who
raised the issue of the frequency of required equipment examinations
referred to maintenance schedules for diesel-powered equipment in place
at their mines, with examination intervals of one week, two weeks, or
every 150 hours of equipment operation. Other commenters stated that
examination requirements for diesel- powered equipment should be
similar to those for electrical equipment. The latter comment is
consistent with the unanimous recommendation of the Advisory Committee
that diesel-powered equipment be maintained on the same basis as
electrical equipment.
MSHA has concluded that testing and examination of diesel-powered
equipment on a weekly basis will ensure that equipment is being
maintained in safe and healthful condition. Weekly examination of
electrical equipment in underground coal mines has been required and
has served as an effective check for adequate equipment maintenance for
more than 20 years. Weekly examinations have consequently become an
accepted element of routine equipment maintenance in the coal mining
industry. Diesel equipment and electrical equipment in the underground
coal mine environment present many of the same hazards. Paragraph (f)
therefore provides for weekly testing and examination of diesel-powered
equipment by a person qualified under Sec. 75.1915.
Several commenters stated that the weekly examinations under
paragraph (f) should be required only for approved components. Neither
the proposed rule nor the final rule contains this limitation. The
proposal would have specified that the weekly examinations be conducted
in accordance with approved checklists, which are lists developed, with
the assistance of MSHA, by an equipment manufacturer who is seeking
MSHA approval. The proposal would have required fully assembled machine
MSHA approval of all diesel-powered equipment, except for a ``limited
class'' of light-duty nonpermissible equipment and stationary
unattended equipment. The final rule requires full machine approval
only for permissible equipment; nonpermissible equipment must only be
provided with an approved engine. MSHA nonetheless believes that
certain machine features, although not subject to MSHA approval, should
be inspected as part of the regular examination.
Paragraph (f)(1) requires that examinations and tests be conducted
in accordance with approved checklists and manufacturers' maintenance
manuals. These checklists are to be used in conjunction with checklists
and instructions included in manufacturers' maintenance manuals.
Commenters supported the use of checklists for examinations and
tests of diesel-powered equipment. One commenter advocated that
maintenance requirements be stated in general terms to accommodate new
equipment design and improved technology in the future. MSHA agrees
with this comment, and the use of equipment-specific permissibility/
approval checklists and equipment manufacturers' maintenance manuals
should achieve this result. MSHA would also consider a mine operator to
be in compliance with this provision if the operator developed its own
checklist format based on and consistent with the manufacturers'
maintenance manuals.
Equipment manufacturers, with the assistance of MSHA, currently
develop such checklists as part of the MSHA approval process. These
checklists are designed to provide specific guidance to mine operators
in verifying that approved equipment is in approved condition.
Permissibility checklists are used to determine whether maintenance or
repair is needed to bring the equipment back into approved condition;
manufacturers' maintenance manuals complement these checklists by
providing mine operators with specific instructions on how to conduct
the necessary maintenance or repair. MSHA intends that the approved
checklists referred to in this paragraph for diesel-powered equipment
under part 7 will be similar to the permissibility checklists used for
part 36-approved machines.
Commenters supported the use of checklists for examinations and
tests of diesel-powered equipment. One commenter advocated that
equipment maintenance requirements be stated in general terms to
accommodate new equipment design and future technological improvements.
MSHA believes that the use of equipment-specific permissibility/
approval checklists should achieve this result, and has included
language in the final rule that provides for the use of equipment-
specific manufacturers' maintenance manuals in conjunction with the
approved checklists in conducting necessary maintenance. MSHA would
also consider a mine operator to be in compliance with this provision
if operators developed their own checklist formats based on and
consistent with the manufacturer's maintenance manuals.
Paragraph (f)(2) requires that persons performing weekly
examinations and tests of diesel-powered equipment under this paragraph
shall make a record when the equipment is not in approved or safe
condition. The record must include the equipment that is not in
approved or safe condition, the defect found, and the corrective action
taken. This requirement has been adopted with modification from the
proposed rule. Under the proposed rule, a record of all weekly
equipment examinations would have been required, and recordkeeping
[[Page 55490]]
would not have been limited to those examinations that disclosed a
defect. Under the final rule the recordkeeping burden has been reduced,
consistent with efforts to reduce the paperwork burdens placed on the
regulated public.
Commenters generally supported the concept of recording of
examinations, and a number of commenters provided information on the
type of records of equipment examination that were maintained at their
mines. The record required by this paragraph may be entered or recorded
by the qualified person who performed the examination, or by a
responsible mine official, such as a foreman or superintendent.
Paragraph (g) requires the mine operator to develop and implement
written standard operating procedures for weekly testing and evaluation
of undiluted exhaust emissions from diesel-powered equipment used where
permissible electrical equipment is required, and from heavy-duty
diesel-powered equipment as defined in Sec. 75.1908(a), in use
underground. The paragraph also requires that specific aspects of the
testing and evaluation process be addressed in the procedures. The
final rule differs from the proposal in that the proposal would have
required emission testing of all diesel-powered equipment underground,
while the final rule narrows the requirement for such testing to
permissible and heavy-duty nonpermissible equipment. The final rule
also differs slightly from the proposal in the type of training
required for the person who tests and evaluates the exhaust emissions.
The proposed emission testing requirements elicited the most
controversy among commenters of all of the requirements in this
section. Some commenters acknowledged that emission testing could be
useful in monitoring the general operating condition of a diesel engine
in identifying diesel equipment that needs maintenance. These
commenters nonetheless expressed serious concern that a standardized
in-mine test for undiluted exhaust emissions had not yet been devised,
and until such a test was developed there would be no consistency in
test results. These commenters recommended that emission test
requirements not be included in the final rule. In response to these
comments, the final rule limits required undiluted exhaust emission
testing to permissible equipment and to heavy-duty nonpermissible
equipment, as defined under Sec. 75.1908(a). In-mine tests for diesel
exhaust emissions have in fact been developed for these types of
equipment. Permissible equipment and heavy-duty nonpermissible
equipment are also typically the types of equipment that operate under
load for extended periods of time, and consequently generate high
levels of emissions relative to other types of equipment. Regular
testing of the exhaust emissions of this equipment will help to ensure
that this equipment is properly maintained.
A number of commenters supplied extensive information on emissions
tests that had been developed and were being conducted at their mine,
stating that such tests provided a valuable indication of engines that
were in need of maintenance. Some commenters who supported the
requirement for emissions testing in the proposed rule nonetheless
recommended different testing intervals, ranging from two times per
shift to once a month. One commenter stated that an emissions test
frequency of one time per month was appropriate for light-duty
equipment, while another commenter recommended that emissions be tested
each week by a person qualified under Sec. 75.1915, and during each
shift by the equipment operator. The final rule adopts the proposed
requirement for weekly exhaust emissions testing, consistent with the
weekly examinations and testing requirement of paragraph (f). A weekly
testing interval is of sufficient frequency to ensure that
deteriorating engines are identified and serviced before they create a
potential health hazard for miners in the area.
A number of commenters questioned where the exhaust gas should be
sampled, some stating that they sampled diluted exhaust gas either in
the equipment operator's compartment or at a significant distance from
the tailpipe, such as 2 or 3 feet, and in one case 10 feet away.
Several commenters stated that emissions test should be taken no more
than 3 inches from the exhaust pipe if a particulate probe is not
provided, because greater distances will not provide meaningful
results. One commenter found that testing 2 feet away from the exhaust
was very unreliable, and that the test results would depend on which
way the machine was facing. Another commenter believed that test
procedures used by some mine operators were intended to circumvent the
goal of testing, which is to gauge engine performance and identify
equipment that needs maintenance. Other commenters stated that while
samples taken in the operator's compartment or away from the tailpipe
can provide valuable information, inconsistent dilution prevents such
samples from giving the most accurate indication of engine condition.
One commenter's experience has shown that samples taken directly from
the exhaust tailpipe provide a more accurate analysis of engine
performance, and that samples drawn further away are influenced too
much by the variables of mine ventilation. MSHA agrees with the
commenters who are concerned about these variables, not least among
them mine ventilation, that can dilute and distort emission samples
that are taken any distance away from the machine tailpipe. A
significantly diluted sample may fail to indicate declining engine
performance and may not trigger the necessary corrective maintenance,
thereby exposing miners to unhealthy levels of gaseous emissions. In
response to these concerns, MSHA has concluded that adopting the
requirement in the proposal for sampling of the undiluted exhaust
emissions is the best way to ensure that the measurements will provide
an accurate indication of deteriorating engine performance. The final
rule specifically requires the testing of undiluted exhaust emissions,
which means that emission samples required must be taken directly from
the tailpipe, not at any distance away.
Paragraph (g) specifies that the person performing the weekly
testing and evaluation of exhaust emissions be trained to perform the
task. The person is not required to be qualified under Sec. 75.1915,
but does have to be adequately trained. This is a slight modification
from the proposed rule, which would have required the person conducting
emissions tests to demonstrate to a person qualified under Sec. 75.1915
the capability to perform the tests. MSHA has concluded that the
requirement in the proposed rule that the training be conducted by a
qualified person is an unnecessary limitation. Mine operators have the
responsibility of ensuring that persons who perform such tasks are
adequately instructed in the activity. An important part of carrying
out that responsibility is making sure that the persons conducting task
training have the requisite knowledge and experience. Accordingly, the
final rule simply requires that persons who test and evaluate emissions
receive the necessary task training.
Paragraph (g)(1) requires that the emissions testing procedures
developed by the mine operator include a method for achieving a
repeatable loaded engine operating condition for each type of
equipment, and is identical to what was proposed. Most commenters
stated that a loaded engine test was not feasible for all types of
equipment, specifically diesel machines equipped with clutches. Several
commenters emphasized the difficulty of analyzing
[[Page 55491]]
the exhaust emissions of a loaded engine without exposing miners to the
danger of sudden equipment movement. Other commenters stated that valid
samples could not be obtained if the engine were not under load. In
response to these commenters, and as discussed above, the final rule
limits the requirement for exhaust testing to permissible equipment and
heavy-duty nonpermissible equipment. These types of equipment are
generally not equipped with clutched transmissions, and therefore do
not present the problems identified by commenters that would exist with
loaded engine tests for diesel equipment with clutches. As mentioned
earlier, MSHA has developed loaded engine test procedures for the
equipment subject to testing under the final rule.
Paragraph (g)(2) requires that the procedures for weekly testing
and evaluation of the undiluted exhaust emissions of diesel engines
specify sampling and analytical methods that include calibration of
instrumentation capable of accurately detecting carbon monoxide in the
expected concentrations. Commenters indicated that instruments are
available and currently being used for accurate emissions testing.
Several commenters stated that testing should not be limited to carbon
monoxide, stating that they were currently testing for other gases,
such as sulfur dioxide and the oxides of nitrogen. Other commenters
were of the opinion that carbon monoxide concentrations were the best
indicator of engine performance.
After consideration of all comments, MSHA has concluded that
sampling for carbon monoxide alone is sufficient for determining a
change in engine performance that may reflect a need for maintenance.
Data indicates that carbon monoxide increases the most among the
exhaust gases when an engine is poorly maintained, and is the best
indicator that an engine needs attention. See, Report of the Bureau of
Mines, U.S. Department of the Interior, ``Relationship of Underground
Diesel Engine Maintenance to Emissions'' (December 1983). Sampling for
nitrogen dioxide is required by Sec. 70.1900 of the final rule. This
will ensure that miners are not exposed to contaminants at levels above
the applicable limits.
Paragraph (g)(3) requires that the procedures for emissions testing
and evaluation include evaluation and interpretation of the emission
test results. Commenters generally supported this requirement, and
several commenters provided information on their evaluation and
interpretation of results. This provision has been adopted unchanged
from the proposed rule.
Paragraph (g)(4), like the proposal, requires that the testing
procedures developed by the operator specify the concentration or
changes in concentration of carbon monoxide that will indicate a change
in engine performance. The paragraph also provides that concentrations
of carbon monoxide shall not exceed 2500 parts per million, which is
the limit for carbon monoxide established in the test procedures for
Category B engines in subpart E of part 7 of the final rule. This
aspect of the proposal received little comment, and has been adopted
without change in the final rule.
Paragraph (g)(5) requires that the testing and evaluation
procedures address the maintenance of records that are necessary to
track engine performance. Commenters supported this requirement and
indicated that some mines are already maintaining emissions records.
The proposed rule would have required that the procedures address
``maintenance and retention of necessary records''. MSHA has added
language to this paragraph to eliminate any ambiguity that might have
been created by the term ``necessary records'', by specifying the
purpose of the records required under this paragraph. MSHA has also
eliminated the reference in the proposed rule to the ``retention'' of
records, and has chosen instead to address retention of records in a
new paragraph (h) in this section, discussed below.
Paragraphs (h)(1) and (h)(2) provide that records required by
paragraphs (f)(2) and (g)(5) of this section must be recorded in a
secure book that is not susceptible to alteration, or recorded
electronically in a computer system that is secure and not susceptible
to alteration. The records must be retained at a surface location for
at least 1 year and made available for inspection by an authorized
representative of the Secretary and by miners' representatives.
The proposed rule did not address the availability of or access to
records under this section. One commenter recommended that records of
weekly examination be accessible to miners' representatives. MSHA
agrees with this comment, and has revised the paragraph to provide
miners' representatives with access to records. The final rule also
requires such access for authorized representatives of the Secretary,
to allow MSHA inspectors to review records to verify that examinations
and tests required under this section have been conducted.
The final rule does not specify a particular way of making records,
only that they are to be recorded in a manner that is not susceptible
to alteration. A detailed discussion on the issue of recordkeeping and
electronic records can be found under ``Recordkeeping Requirements'' in
the General Discussion section of this preamble.
The proposed rule would have required that the emission testing
procedures under paragraph (g) include the designation of training of
the individual who performs the tests. This requirement has not been
adopted in the final rule. Instead, as discussed earlier, the rule
imposes a performance-based requirement that emissions testing and
evaluation under this paragraph be conducted by a person who has been
trained to perform the task. Mine operators are consequently
responsible for ensuring that individuals who test and evaluate
emissions receive the training necessary to ensure their competence.
The ability of these persons to discharge their responsibilities is of
much greater concern to MSHA than the training they receive to achieve
it, and the final rule reflects this emphasis.
Finally, several commenters recommended that this section include a
requirement for regular examination of fire suppression systems.
Examination of fire suppression systems is not addressed here, but
instead is dealt with in Sec. 75.1911 of the final rule, which provides
that equipment fire suppression systems be visually inspected at least
once each week, and be tested and maintained in accordance with the
manufacturer's recommended inspection and maintenance program.
Paragraph (i) provides that diesel-powered equipment must be
maintained in accordance with this part beginning 12 months after the
date of publication of the final rule. This time is allowed for the
development of a training and qualification program under Sec. 75.1915
and for the training of individuals who perform work on diesel-powered
equipment. MSHA recognizes that the resources available for training in
particular geographical areas may be limited in some cases, and that
competent trainers may be in significant demand as mine operators
prepare to comply with the requirements of the final rule. A one-year
delayed effective date for the requirements of this section should
afford the mining community sufficient time to prepare for compliance.
[[Page 55492]]
Section 75.1915 Training And Qualification Of Persons Working On
Diesel-Powered Equipment
This section of the final rule requires a training and
qualification program for persons who perform maintenance, repairs,
examinations and tests on diesel-powered equipment, as required by
Sec. 75.1914. These critical tasks must be performed correctly for
diesel equipment to be maintained in safe condition with acceptable
levels of emissions. The final rule sets minimum, performance-based
requirements for training and qualification programs, and requires
successful completion of such a program for a person to be qualified to
perform diesel maintenance, repairs, examinations, and tests.
The final rule differs from the proposed rule in several respects:
it does not require the training and qualification programs to be
approved by MSHA; it does not specify an interval for retraining; it
clarifies that the rule does not require MSHA approval of instructors
who provide training; and it eliminates the use of the term ``diesel
mechanic''.
Paragraph (a) of this section of the final rule provides that in
order to be qualified to perform maintenance, repairs, examinations,
and tests on diesel-powered equipment, as required by Sec. 75.1914, a
person must complete a training and qualification program which meets
the requirements of the section. A qualified person is required to be
retrained when necessary to maintain the ability to perform all
assigned maintenance, repairs, examinations, and tests. The final rule
does not require, as would have the proposed rule, that MSHA approve
training and qualification programs developed under this section.
Although there was virtually universal agreement among commenters
that some form of training was essential for persons working on diesel
equipment, commenters disagreed about the need for a formal training
and qualification program and the necessity of MSHA review and approval
of such programs. Some commenters were of the opinion that persons
working on diesel equipment should be formally qualified, and that
diesel training programs for qualification should meet strict minimum
standards and be subject to approval by MSHA. One commenter stated that
if strict training requirements were not included in the standard, the
necessary training would not be provided.
Other commenters opposed requiring a formal program with specific
requirements, advocating as an alternative performance-oriented
standards that could be adapted to a mine's specific needs. One
commenter stated that a formal qualification scheme was unnecessary,
and that diesel maintenance training should be provided on an as-needed
basis in the same manner as task training under part 48. Another
commenter maintained that the benefits realized from a formal
qualification program would not justify the additional administrative
burdens of such a program. The Office of Management and Budget guidance
comments directed MSHA to reexamine whether all of the information
proposed to be submitted to MSHA for approval of training and
qualification programs had practical utility and imposed the least
burden on mine operators.
Numerous other commenters, while supporting the establishment of
procedures to qualify persons to perform work on diesel equipment, were
opposed to the proposed requirement that MSHA approve training and
qualification programs. Many commenters indicated that very good diesel
equipment maintenance training is already being provided by mine
operators as well as equipment manufacturers, without MSHA review or
approval. In contrast, other commenters maintained that training
programs should meet the approval of all interested parties, including
MSHA and the representative of miners, to ensure that the training is
adequate. The Diesel Advisory Committee had unanimously recommended
that MSHA require persons performing work on approved diesel equipment
features be trained and tested for competency, and that the training
and testing be approved by MSHA.
After careful consideration of all of these views and comments,
MSHA has concluded that a basic structure for training and
qualification programs for persons performing certain work on diesel
equipment is necessary. Properly trained persons are fundamental to
adequate maintenance of diesel-powered equipment. To meet this
objective, MSHA believes minimum criteria for the training and
qualification of these persons are essential. Paragraph (a) therefore
provides that to be qualified to perform diesel equipment maintenance,
repairs, examinations, and tests, as required by Sec. 75.1914, a person
must successfully complete a training and qualification program meeting
the requirements of the section.
The proposal that MSHA review and approve training and
qualification programs is not adopted in the final rule. MSHA's paper
review of training and qualification programs, as proposed, could
provide an initial check of the quality of the program. Such a review
would not, however, ensure that the program is successful in its
implementation. Rather than expending Agency resources on the review
and approval of diesel training programs, MSHA will direct those
resources toward verification of the effectiveness of training and
qualification programs in their execution. Similarly, mine operators
and training providers can focus on the development and administration
of their training and qualification programs rather than on procedures
to gain MSHA approval. The rulemaking record contains a number of well-
designed diesel training plans already in effect, demonstrating that
the mining community has the expertise needed to develop and implement
effective training programs. MSHA will closely monitor the
effectiveness of the training programs implemented under this section.
Paragraph (a) also requires retraining when needed. The proposed
rule would have required qualified persons to undergo retraining every
12 months. Some commenters to the proposed rule opposed the
establishment of a specific requirement for annual retraining, stating
that the mining industry needed performance-oriented standards that
could be adapted to mine-specific needs for maintenance and training.
Other commenters stated that an annual retraining requirement was
necessary to ensure that persons working on diesel-powered equipment
maintained the necessary knowledge and expertise over time.
MSHA considers retraining to be an important part of any training
program. The final rule, however, does not mandate retraining at
specified intervals. MSHA has concluded that mine operators should
tailor the frequency of retraining to the conditions and practices at
each mine, to ensure that all persons who work on diesel-powered
equipment maintain the requisite level of expertise. Factors that could
affect the timing of retraining include the frequency with which the
qualified person works on specific pieces of diesel equipment; newly
developed techniques for performing the required inspections and tests;
and any modifications that may have been made to the equipment since
the last training. Frequent retraining may be necessary at some mines
to ensure that qualified persons retain sufficient skill and knowledge
to perform their jobs effectively. At other mines where conditions are
less changeable, retraining at greater intervals may be appropriate.
[[Page 55493]]
Paragraph (a) of the final rule also eliminates the term ``diesel
mechanic'', was used in the proposal to identify those persons
qualified to perform maintenance and repairs of approved features of
diesel equipment. Many commenters to the proposed rule objected to the
use of the term, stating that it would result in the creation of a new
job title or classification. MSHA did not intend to establish a new job
classification through the use of the term ``diesel mechanic'', and
concludes from the comments that its use would result in confusion. The
term ``diesel mechanic'' has therefore not been adopted in the final
rule.
Finally, the phrase ``examinations and tests'' has been included in
paragraph (a) of the final rule, reflecting that a person qualified
under this section would be authorized to conduct weekly examinations
and tests of diesel-powered equipment under Sec. 75.1914(f), in
addition to maintenance and repairs of such equipment under
Sec. 75.1914(b).
Paragraph (b) provides a basic structure for training and
qualification programs, but is intended at the same time to provide
mine operators with sufficient latitude in developing their programs.
MSHA believes that training and qualification programs will be most
effective if they are tailored to specific mining conditions and
equipment in use at the mine, as well as to the skill levels and
experience of the persons being trained.
A number of commenters reported that they already have training and
qualification programs in place at their mines, and provided
descriptions and documentation of these programs. Many of these
programs utilize training at off-site facilities, such as community
colleges and technical and trade schools. Commenters also indicated
that mining equipment manufacturers are typically called upon to
provide training. These programs generally include classroom training
modules as well as hands-on in-mine training on specific pieces of
equipment. Commenters stated that the duration of training programs
could be from three days to eight weeks. The length of the program was
generally dependent upon how much diesel-powered equipment was used at
the mine, as well as on the previous experience and skill level of the
persons being trained.
MSHA anticipates that local community colleges and technical
schools will assist mine operators in developing the training and
qualification programs required under this section. Commenters
indicated that this type of assistance is already being provided to
mine operators in a number of areas of the country.
Paragraph (b)(1) requires that training courses be presented by a
competent instructor, in contrast to the proposed rule, which would
have required that courses for training and retraining be conducted by
either a qualified diesel mechanic or ``other instructor determined by
MSHA to be qualified.'' Several commenters objected to this aspect of
the proposal, based on their belief that the proposal required some
type of formal approval by MSHA before anyone other than a qualified
person could conduct diesel training under this section. A number of
other commenters believed that such approval would only add an
unnecessary procedural hurdle to providing training. Contrary to the
understanding of such commenters, MSHA did not intend by the proposal
to approve training instructors. The language of the final rule has
been clarified to provide that courses may be presented by a competent
instructor. A competent instructor under paragraph (b)(1) could be a
person qualified under Sec. 75.1915, an instructor from a trade school
or college, or a person experienced in diesel maintenance, such as a
representative of an equipment or engine manufacturer, or even the
chief of maintenance at the mine, provided that the instructor has the
necessary technical expertise.
Paragraph (b)(2) of the final rule provides that the training and
qualification program must be sufficient to prepare or update a
person's ability to perform all assigned tasks with respect to diesel-
powered equipment maintenance, repairs, examinations, and tests. This
paragraph incorporates the requirements of proposed paragraphs (e)(2)
and (e)(3), except that it substitutes the term ``person'' for the term
``diesel mechanic,'' for the reasons stated in the discussion of
paragraph (a) of this section. Several commenters were opposed to the
requirement in proposed paragraph (e)(3) that courses in the training
program address each piece of diesel-powered equipment in use at the
mine, stating that this could be an unnecessary burden at mines that
operate a variety of types of diesel-powered equipment. These
commenters stated that if an individual never worked on certain pieces
of equipment, requiring that individual to receive training on all
equipment in use at the mine would be unnecessary.
MSHA did not intend proposed paragraph (e)(3) to require that each
qualified person be trained on all types of diesel-powered equipment in
use in the mine, only those pieces of diesel-powered equipment the
qualified person actually works on. However, the language of proposed
paragraph (e)(3) could be interpreted to require that the courses in
the training program cover all pieces of diesel equipment in use at the
mine.
MSHA agrees with the commenters that training should be tailored to
the duties and responsibilities of the individual qualified person. The
language in the final rule has therefore been clarified to reflect this
concept. A qualified person is not required to be trained on a
particular type of equipment, unless he or she performs work on it.
However, a person who is untrained on a particular type of equipment is
not a qualified person with respect to that equipment, and may not
perform maintenance, repairs, and tests required to be conducted by a
qualified person. Finally, MSHA anticipates that training will address
equipment by model and not by individual machine, unless machines at
the mine with the same model number differ because of field changes or
other special features. In such cases training would need to take into
account any significant differences among machines.
While MSHA's intent is to promote flexibility in the implementation
of training and qualification programs, the final rule does specify
minimum topics of instruction for these programs. Paragraphs (b)(3)(i)
through (b)(3)(vii) of the final rule set forth the specific areas of
instruction that must be covered by a training and qualification
program. Commenters were generally in agreement with the areas of
instruction required under the proposed rule, and the language of the
final rule is virtually the same as what was proposed''.
Paragraph (b)(3)(i) requires that training programs address the
``requirements of subpart T of this part''. Several commenters
recommended that the phrase ``as applicable'' be added to this
requirement, to eliminate the need for training to address requirements
that may not be directly applicable at the specific mine. This
recommendation is not adopted in the final rule. MSHA believes that a
person qualified under this section should have, at a minimum, basic
familiarity with the scope of subpart T and the diesel-powered
equipment safety standards. However, MSHA does not intend that this
aspect of the final rule require exhaustive coverage of requirements
that have no application to the mine in question. The well-designed,
mine-specific training program contemplated by this section will focus
on the requirements that are the most relevant. For example, if a mine
does not store diesel fuel underground, qualified persons working
[[Page 55494]]
at that mine would not be expected to have extensive knowledge of the
requirements of the standards governing fuel storage. Qualified persons
should nonetheless be aware that subpart T contains provisions that
address underground fuel storage.
Paragraph (b)(3)(ii) is virtually identical to proposed paragraph
(e)(4)(ii), and requires that the training program address the use of
power package or machine checklists to conduct tests to ensure that
diesel equipment is in approved and safe condition, with acceptable
emission levels. Some commenters reported that maintenance of the
permissibility features of approved equipment was often neglected, and
emphasized the importance of using only trained personnel to evaluate
these features. This requirement is intended to ensure that training
addresses the evaluation of the equipment's permissibility features.
Several commenters also questioned the meaning of the term ``safe
operating condition''. The term has been changed to ``safe condition''
to conform to the terminology in Sec. 75.1914. MSHA intends that ``safe
condition'' used in this paragraph means that the equipment has been
maintained in compliance with subpart T of this part and does not
present a hazard to miners. Finally, the language of this paragraph has
been slightly revised to delete the term ``appropriate'' from the
phrase ``to conduct appropriate tests'', because it is unnecessary and
redundant.
Paragraph (b)(3)(iii) of this section is identical to proposed
paragraph (e)(4)(iii), and requires that the training program cover the
proper maintenance of approved features and the correct use of
appropriate maintenance manuals, including machine adjustments,
service, and assembly. Paragraph (b)(3)(iii) is different from
paragraph (b)(3)(ii) in that it addresses proper maintenance of
equipment, while paragraph (b)(3)(ii) addresses tests to ensure
permissibility.
Paragraph (b)(3)(iv) of the final rule requires that training under
this section address tests and maintenance of fire suppression system
on diesel-powered equipment. The final rule uses the phrase ``fire
suppression system'' rather than ``fire protection system,'' which was
used in the proposed rule, to conform the language of the final rule to
terminology that is more commonly in use. The purpose of this
requirement is to ensure that a qualified person has sufficient
familiarity with the elements of fire suppression systems used on
diesel equipment.
Paragraph (b)(3)(v) of this section requires that fire and ignition
sources and their control and elimination, including cleaning the
equipment, be addressed by the training program. The phrase ``including
cleaning of the equipment'' has been added in response to comments
emphasizing the importance of frequent cleaning of equipment to prevent
the accumulation of combustible materials such as oil, grease and float
coal dust and thereby reduce the risk of fire. This requirement is
consistent with and is intended to reinforce compliance with
Sec. 75.400, which has been revised in this final rule to specifically
prohibit accumulations of combustible material on diesel-powered
equipment.
Paragraph (b)(3)(vi) of this section requires that the training
program address safe fueling procedures and maintenance of the
equipment's fuel system. The importance of proper refueling procedures
is illustrated by the analysis of the Canadian fire accident data in
the discussion of Sec. 75.1908. These data show that the failure to
follow proper refueling procedures resulted in several fires.
Paragraph (b)(3)(vii), like the proposal, requires that the
training program address maintenance and testing of the engine's intake
air system. A number of commenters reported that failure to replace
dirty intake air filters was the most frequent cause of excessive
levels of smoke and carbon monoxide from otherwise properly adjusted
engines.
Proposed paragraph (e)(4)(viii) would have required the training
course to address tests and maintenance of the engine shutdown device.
Because engine shutdown devices are in fact components of permissible
equipment, training covering these devices will already be required by
paragraphs (b)(3) (ii) and (iii) of this section, discussed above. The
language of proposed paragraph (e)(4)(viii) has therefore not been
included in the final rule.
Proposed paragraph (e)(4)(ix) would have given the district manager
the authority to require the training program to cover additional
subjects necessary to address specific health and safety needs. This
provision has not been adopted in the final rule, which is designed to
be more performance-oriented. As discussed above, the requirements of
this section are intended to result in the development of training
programs that are tailored to the specific needs of each mine,
including the equipment being used and the skill levels of the persons
receiving the training. Failure to address mine-specific health and
safety needs in the training program may result in MSHA determining
that a mine operator is not in compliance with Sec. 75.1915.
Additionally, the proposed rule would have required MSHA approval of
training programs and would have provided a framework for the exercise
of district manager authority under proposed paragraph (e)(4)(ix). As
discussed above, the final rule does not require MSHA approval of
training programs. For these reasons, this proposed provision has not
been adopted in the final rule.
Paragraph (b)(4) requires the training and qualification program to
include an examination that requires demonstration of the ability to
perform all assigned tasks with respect to diesel equipment
maintenance, repairs, examinations, and tests. There is no specific
requirement that the examination be in writing, although an examination
that effectively assesses competence will most likely include a written
test as well as a practical portion that allows a hands-on evaluation
of a person's abilities. Under the proposed rule, a minimum score of 80
percent would have been required on any written portion of a
qualification examination. Although some commenters supported the
concept, MSHA has concluded that mandating a minimum score is
unnecessary when a written portion is not a required part of the
examination. Further, such a specific requirement is at odds with the
performance-oriented approach of this paragraph. The requirement for a
minimum score has therefore been omitted from the final rule.
Paragraph (b)(5) requires that the training and qualification
program be in writing, and contain a description of the course content,
materials, and teaching methods to be used for initial training and
retraining. The language of this paragraph is substantially the same as
proposed paragraph (d)(1), except that the word ``approved'' has been
omitted. As discussed above, the program will not be subject to MSHA
approval under the final rule.
The requirements of proposed paragraphs (d)(2) and (d)(3) have not
been adopted in the final rule. Specifically, proposed paragraph (d)(2)
would have required that the training and qualification program include
a copy of the examination, to allow MSHA to review the examination as
part of the approval process. Because the final rule does not require
MSHA approval, and also because a written examination is not required,
a copy of the examination does not need to be included as part of the
program.
Proposed paragraph (d)(3) would have required that the program
include a description of the evaluation program to be used for
retraining to assess the knowledge, skills, and ability of the
[[Page 55495]]
qualified person. This requirement has not been included in the final
rule, consistent with MSHA's intention to measure the effectiveness of
training and qualification programs by how well diesel-powered
equipment is being maintained at the mine, rather than by the adequacy
of a written program. Consequently, the final rule does not require a
retraining evaluation program, but MSHA expects that mine operators
will closely monitor the maintenance of diesel equipment at their
mines, and will ensure that qualified persons receive the necessary
retraining.
Paragraph (c) of this section requires the mine operator to
maintain a copy of the training and qualification program required by
this section and a record of the names of all persons qualified under
the program. Paragraph (c)(1) requires that the record of the names of
qualified persons be made in a manner that is not susceptible to
alteration or recorded electronically in a computer system that is
secure and not susceptible to alteration. Under paragraph (c)(2), the
training and qualification program and the record of qualified persons
must be kept at a surface location of the mine and made available for
inspection by an authorized representative of the Secretary and by
miners' representatives. Paragraph (c) incorporates, with certain
revisions, the requirements originally proposed in Secs. 75.1916 (i)
and (j). Proposed Secs. 75.1916 (i) and (j) would have required a list
of current instructors also to be included in the training and
qualification program and, in addition to the names of all qualified
persons, the dates of qualification and the date of the last
retraining. MSHA has removed these additional recordkeeping
requirements from the final rule, consistent with the Agency's
intention to gauge the adequacy of training and retraining by how
effectively diesel-powered equipment at the mine is maintained. The
final rule does not specify a particular method for maintaining the
record of qualified persons, only that it is not susceptible to
alteration. A detailed discussion of recordkeeping and electronic
records can be found under the heading ``Recordkeeping Requirements''
in the General Discussion section of this preamble.
Finally, the proposed rule specified procedures in Sec. 75.1916 for
MSHA's administration of training and qualification programs. Among
other things, the proposed rule set forth a process for MSHA review and
approval of the training and qualification program required under
Sec. 75.1915, and established procedures for the revocation of
individual qualifications. Because MSHA will not be formally reviewing
and approving training and qualification programs, procedural
requirements for review and approval are unnecessary. Consequently, the
provisions proposed in Sec. 75.1916 have not been retained in the final
rule, with the exception of the requirements of proposed
Secs. 75.1916(i) and (j), as discussed above.
Section 75.1916 Operation Of Diesel-Powered Equipment
Section 75.1916 addresses speed limits and other traffic
restriction on roadways in underground coal mines where diesel-powered
equipment is operated. This section also prohibits unnecessary idling
of diesel-powered equipment, as well as the operation of unattended
diesel-powered equipment.
The Diesel Advisory Committee advocated MSHA regulation of
operating conditions of diesel-powered equipment, recommending proposal
of a rule that addressed speed limits, road conditions, and operator
control of vehicles. This section is intended to ensure that diesel-
powered equipment underground is operated in a safe manner, and
requires that operating speeds of diesel-powered equipment be
consistent with conditions in the mine, and that operators of diesel-
powered equipment maintain full control of the equipment when it is in
motion. Standardized traffic rules, including speed, signals, and
warning signs, are required to be established at each mine and
followed.
The final rule recognizes that the safe operating speed for a
particular piece of diesel-powered equipment depends greatly on the
specific mining conditions and the type of equipment being operated,
and as a result the final rule does not establish a universal speed
limit for diesel-powered equipment operated in underground coal mines.
Finally, idling of mobile diesel-powered equipment is prohibited,
except as required in normal mining operations. Operation of unattended
diesel-powered equipment is also prohibited under this section.
Several commenters recommended elimination of the requirements of
this section, stating that the proposed standards were too vague and
could result in inconsistent enforcement. Some of these commenters
suggested reducing the proposed requirements of this section to a
single requirement that the mine operator establish traffic rules,
appropriate for the specific mine conditions at each mine, that address
speed and operator control of equipment. A number of commenters also
pointed out that existing Sec. 75.1403 gives MSHA the authority to
regulate hazards arising from the transportation of men and materials
at underground coal mines. These commenters believed that
transportation hazards were already adequately covered under
Sec. 75.1403, and that additional regulation was therefore unnecessary.
The existing authority to issue safeguards under Sec. 75.1403 does
not make the requirements of this section unnecessary. Section 75.1403
authorizes an MSHA inspector to issue a ``safeguard notice'' when the
inspector determines that a transportation hazard exists at a mine and
the hazard is not already addressed by a mandatory standard. The
``safeguard notice'', issued by an MSHA inspector to the mine operator,
identifies the nature of the hazard and establishes requirements based
on the actual conditions or practices that constitute a transportation
hazard at the particular mine. After the mine operator is given a
reasonable time to come into compliance with the requirements set forth
in the safeguard notice, the safeguard has the force and effect of a
mandatory standard at the mine and can be enforced as such. Sections
75.1403-1 through 75.1403-11 contain criteria to guide inspectors in
issuing safeguards, covering a wide range of potential transportation
hazards, such as clearance distances on belt conveyors and track
haulage roads, brakes on hoists and elevators, and safety gates for
entrances to shafts and slopes.
Safeguards are not a substitute for the mandatory requirements in
Sec. 75.1916. Although some of the topics covered in this section, such
as speed limits and roadway conditions, are included as safeguard
criteria in Secs. 75.1403-1 through 75.1403-11, the criteria are not
enforceable unless and until they have been incorporated in a safeguard
notice, after an MSHA inspector has determined that a hazard exists. In
contrast, the requirements of this section of the final rule apply at
all underground coal mines where diesel-powered equipment is used. In
addition, safeguard criteria are intended to be tailored to the unique
conditions and practices at an individual mine, while the requirements
in this section are general in nature, although mine operators are
given the flexibility to set traffic rules appropriate for the
conditions at their mines. The final rule therefore does not reflect
the opinion of some commenters that the requirements under this section
are unnecessary.
The requirements of this section specifically govern the manner and
conditions under which diesel-powered
[[Page 55496]]
equipment operates in underground coal mines, and recognize that
diesel-powered equipment tends to be much larger and more powerful, and
to have the ability to travel at much greater speeds than electric-
powered equipment. Some types of diesel-powered equipment used in
underground coal mines, such as pickup trucks, are designed for use on
highways, and can travel at speeds in excess of 60 miles per hour
(mph). In comparison, a typical piece of mobile rubber-tired battery-
powered equipment will have a top speed of less than 10 mph. The
potential traffic hazards are therefore significantly greater in the
operation of diesel-powered equipment, and there is a resulting need
for the minimum requirements set by the final rule at mines where
diesel-powered equipment is operated.
Paragraph (a) of this section adopts the requirements of the
proposal and provides that operating speeds of diesel-powered equipment
must be consistent with the type of equipment being operated, the
conditions of roadways, grades, clearances, visibility, and other
traffic. Under this paragraph diesel-powered equipment must be operated
at all times at safe speeds, which in many cases will be slower than
the maximum speed limit set in the mine-wide traffic rules established
under paragraph (c).
Some commenters recommended that the rule specify a maximum speed
limit, such as 15 mph or 25 mph, that would apply at all underground
coal mines. These commenters stated that a standardized speed limit
would promote compliance because the rules would be the same at all
mines everywhere. A few of these commenters recommended that equipment
be fitted with gear reduction ratios that would make it mechanically
impossible for equipment to be operated at speeds above the limit.
Other commenters opposed the establishment of a universal speed limit
for all mines, stating that safe speeds were highly dependent on
variable mining conditions, and that a speed that is prudent under one
set of circumstances could be quite unsafe, even reckless, under
another.
The requirements of this paragraph recognize that certain mine
conditions and equipment characteristics must be taken into account in
determining the speed at which equipment can be safely operated. Mine
conditions have been a contributing factor in many traffic accidents.
Adverse conditions that can negatively impact equipment safety include
steep grades and slippery mine surfaces, which decrease the
effectiveness of equipment brakes. Particularly large diesel-powered
machines, which can take up nearly an entire mine entry, can present
significant limitations in visibility for the equipment operator, whose
line of vision is below the machine frame. Consequently, the equipment
operator has several large blind spots where other pieces of equipment
and mine personnel cannot be seen. Large haulage units operating in the
same area as small pieces of diesel-powered equipment can create
particularly dangerous traffic patterns. The proposed rule would have
required roadways to be kept as free as practicable from bottom
irregularities or other conditions that could affect control of the
equipment. A number of commenters recommended elimination of this
paragraph, noting that the proposed rule would require standardized
traffic rules and could be used to address concerns about roadway
conditions. Other commenters supported this proposed requirement,
citing the dangers that can result from poorly maintained roads.
Although MSHA agrees that keeping mine roads free from bottom
irregularities, debris, and wet or muddy conditions is important to
safe operation of diesel-powered equipment, the requirements of
paragraphs (a), (b), and (c) of this section of the final rule are
sufficient to address concerns about adverse road conditions. The
requirements of proposed paragraph (a), which would have required
roadway maintenance, have therefore not been adopted in the final rule.
Under the requirements of the final rule, vehicle speed must take
into account roadway conditions and other factors that affect safe
equipment operation. Equipment operators are required to maintain full
control of their equipment, and traffic rules must be established and
followed at each mine where diesel-powered equipment is operated.
Paragraph (b) also adopts the requirements of the proposal and
provides that equipment operators must maintain control of mobile
diesel-powered equipment while it is in motion. Commenters generally
supported this requirement, which recognizes that there may be cases
where the roadway conditions, posted operating speed, and traffic rules
are adequate but other factors interfere with the equipment operator's
ability to exercise full control over the equipment. For example, the
rule would prohibit the operator from carrying tools or supplies in the
operator's compartment that interfere with the operator's ability to
control the equipment. Additionally, equipment controls must be free of
any debris which could obstruct safe operation. Operator inattention
could also constitute a violation of this requirement if the
inattention causes unsafe operation of the equipment.
Paragraph (c) requires that standardized traffic rules, including
speed limits, signals, and warning signs, be established and followed
at each mine. Under this provision, the mine operator must develop
mine-wide traffic rules to address hazards arising from the operation
of diesel-powered equipment, and ensure that mine employees are aware
of the rules and comply with them. This is consistent with the
suggestions of several commenters, who supported simplifying the
proposed rule requirements by a single provision that mine operators
establish safe operating rules appropriate for mine conditions. The
requirements in the final rule are similar to those of the proposal,
except that the final rule provides that traffic rules must be
``followed'', and does not adopt the proposed requirement that the
rules be ``posted.'' Mine operators have the responsibility to take
whatever steps are necessary to ensure that their employees are
familiar with the mine's traffic rules and follow them. Although
posting of traffic rules can serve as a means for mine operators to
facilitate compliance, it is not specifically required under the final
rule.
Commenters who advocated a standardized maximum speed limit at all
underground coal mines, in response to proposed paragraph (b), renewed
this recommendation in their comments to this paragraph. For the
reasons discussed above, the final rule does not impose a universal
speed limit. Some commenters suggested that simply requiring the
establishment of a mine-wide speed limit would eliminate the need for
other traffic rules. MSHA disagrees that restrictions on speed alone
will eliminate potential traffic hazards. The traffic rules required
under this paragraph are intended to address other factors that affect
safe operation of diesel-powered equipment, such as changes in mining
conditions.
Some commenters recommended that MSHA provide criteria for mine
operators to use in establishing mine traffic rules, and that operators
develop traffic plans, consistent with these criteria, that are
reviewed and approved by MSHA. The final rule does not adopt this
recommendation. Although MSHA's review of a mine's traffic rules could
provide a preliminary check on the adequacy of the rules, such a review
will not ensure that they have been effectively implemented. The final
rule reflects MSHA's conclusion that both mine operator and Agency
resources are
[[Page 55497]]
better spent ensuring that traffic rules are being followed. However,
if an MSHA inspector determines that an operator's traffic rules fail
to adequately address the mine's traffic hazards, MSHA will require
revision of the traffic rules.
This paragraph also requires that the traffic rules be followed.
The language in the proposed rule did not specifically require that the
rules be ``followed,'' although MSHA believes that most commenters
understood that the rules must be obeyed. To eliminate any possible
ambiguity or misunderstanding, the rule has been clarified to
specifically require that the rules be complied with.
One commenter recommended that mine operators be required to
investigate and file reports of mine traffic accidents in specific
circumstances, such as where an injury occurs or where a certain amount
of damage is sustained. MSHA regulations at part 50 already require
mine operators to investigate and report certain accidents to MSHA, as
well as to report to MSHA all occupational injuries and illnesses. MSHA
has concluded that there is no compelling reason why traffic accidents
and injuries should be treated differently from other types of mining
accidents and injuries. The final rule therefore does not adopt this
comment.
Paragraph (d) prohibits idling of mobile diesel-powered equipment,
except as required in normal mining operations. This prohibition has
been added to the final rule in response to the concerns of some
commenters, who observed that engines are excessively idled most
frequently in areas where it is impractical to increase air quantities.
This results in high levels of exhaust contaminants in these areas of
the mine, and increases the risks of miner overexposure. The final rule
addresses this problem by prohibiting unnecessary engine idling. The
intent of this provision is that equipment parked at any location,
including the loading point, will be shut down if it is not being used
to do work.
Paragraph (e) has been added to the final rule and prohibits the
operation of unattended diesel-powered equipment. The proposal would
have prohibited portable limited class equipment from being operated
unattended. This prohibition is consistent with the decision not to
adopt the proposed requirements for stationary unattended equipment
into the final rule, and is explained in detail in the preamble
discussion of stationary unattended equipment.
Amendment of Certain Part 75 Standards
MSHA's part 75 sets forth mandatory safety standards for each
underground coal mine. The final rule amends existing Secs. 75.342,
75.400, 75.1710 and 75.1710-1 to extend their application to diesel-
powered equipment, requiring the installation of methane monitors on
certain types of diesel-powered equipment, prohibiting accumulation of
combustible materials on diesel-powered equipment in active workings of
underground coal mines, and requiring diesel-powered face equipment and
shuttle cars to be equipped with substantially constructed cabs or
canopies. Although these existing standards specifically apply to
electric equipment, the hazards that these standards are designed to
address are independent of the power source of the equipment.
The requirements of these four mandatory safety standards have
applied to electric-powered equipment for a number of years, and have
been extremely effective in protecting miners from the hazards of
fires, explosions, and roof falls. The Diesel Advisory Committee
recommended that MSHA review its existing standards to determine
whether any existing safety requirements should be made applicable to
diesel-powered equipment.
In the preamble to the proposed rule, MSHA solicited comments on
extending the applicability of certain listed standards to diesel-
powered equipment. The standards listed in the proposal included
Sec. 75.313 (now Sec. 75.342, methane monitors); Sec. 75.400
(accumulation of combustible materials); Sec. 75.400-2 (cleanup
programs); Secs. 75.523, 75.523-1, and 75.523-2 (emergency
deenergization of self-propelled equipment); Sec. 75.1107-1 (fire
suppression devices); and Secs. 75.1710 and 75.1710-1 (cabs and
canopies on face equipment). MSHA also solicited comments on whether
any other part 75 standards that were not listed should be made
applicable to diesel-powered equipment.
Commenters expressed general support for extending requirements for
methane monitors, brakes, and cabs and canopies to diesel-powered
equipment. Some commenters expressed the view that all equipment safety
features on diesel-powered equipment should be addressed under part 75.
One commenter suggested that all requirements in part 75, particularly
Secs. 75.500 through 75.524 (applicable to battery- and electric-
powered equipment), be applied to diesel-powered equipment. Other
commenters stated that all necessary equipment safety features should
be required as part of the equipment approval process, rather than as
standards under part 75.
The final rule retains MSHA's longstanding approach of including in
part 75 general equipment safety requirements such as methane monitors,
prohibitions against accumulation of combustible materials, and cabs
and canopies. The approach of requiring general safety features in part
75 has been effective in protecting miners in underground coal mines
where electric-powered equipment is in use. As discussed below, the
safety hazards addressed by the standards amended in the final rule are
the same regardless of the equipment's power source.
By including these equipment safety requirements in part 75, mine
operators will have the flexibility to improve safety by making machine
modifications based on specific conditions at each mine. For example,
the selection of an appropriate cab or canopy for a machine is
dependent on mine height and entry width.
Section 75.342 Methane Monitors.
Methane monitors automatically shut down permissible electric
mining equipment used to extract or load coal when methane
concentrations around the equipment reach 2.0 percent. Permissible
diesel equipment can create the same explosion hazard as permissible
electric equipment if operated in the presence of high concentrations
of methane. Also, under certain conditions, a diesel engine can ingest
methane from the mine atmosphere, resulting in uncontrolled
acceleration of the diesel engine during start up or operation, and
produce an ignition of methane in the area.
Methane monitors are recognized as a critical link in the safety
protections designed to prevent mine explosions. These monitors are
normally mounted on equipment that operates in the face area, providing
the first warning that methane gas is accumulating in potentially
dangerous quantities.
The final rule requires methane monitors on all diesel-powered face
cutting machines, continuous miners, longwall face equipment, loading
machines, and other diesel-powered equipment used to extract or load
coal in the working place. By applying the methane monitor requirements
of existing Sec. 75.342 to diesel-powered equipment, miners working
around such equipment will be protected from fire and explosion hazards
to the same degree as miners working in areas where similar electric-
powered equipment is in use.
[[Page 55498]]
Section 75.400 Accumulation of Combustible Materials
The final rule requires that coal dust, loose coal, and other
combustible materials be cleaned up and not permitted to accumulate in
active workings or on electric equipment therein. The hazards of a mine
fire or explosion in an underground coal mine are similar for diesel-
powered and electric-powered equipment. Coal dust can produce a ready
fuel source when combined with the lubricating and hydraulic oils used
in diesel-powered equipment and can start a fire if it comes into
contact with ignition sources on the equipment. As discussed elsewhere,
diesel-powered equipment that is not equipped with surface temperature
controls, such as outby equipment, may have engine and exhaust surfaces
above the ignition temperature of coal dust. Accumulations of coal dust
can also contribute to the propagation and severity of mine fires and
explosions. Because diesel equipment uses large quantities of diesel
fuel and hydraulic fluid, once a fire starts it can quickly spread due
to the close availability of these fuel sources on a diesel machine. A
large fire can then ensue and spread in the mine. By adding the term
``diesel-powered'' to Sec. 75.400, MSHA intends that the longstanding
prohibition against the accumulation of combustible materials will now
be explicitly applied to diesel-powered equipment.
Sections 75.1710 and 75.1710-1--Cabs and Canopies.
The final rule amends Sec. 75.1710 to require diesel-powered face
equipment and shuttle cars to be equipped with substantially
constructed cabs or canopies to protect miners operating such equipment
from roof falls and rib and face rolls. The final rule also applies the
installation requirements for cabs and canopies in Sec. 75.1710-1 to
diesel-powered equipment.
Cabs and canopies provide very effective protection to equipment
operators from the hazards of roof and rib falls and in collisions with
the mine roof and ribs. Since 1972, approximately 250 miner fatalities
have been prevented by cabs and canopies installed on electric
equipment. Some mine operators have recognized the clear safety
benefits of cabs and canopies and have installed these devices on the
diesel-powered self-propelled face equipment in their mines. By
specifically extending the existing requirements in these sections to
diesel-powered self-propelled face equipment, including shuttle cars,
the operators of all such equipment will be afforded the same
protection that is currently provided for operators of electric
equipment.
Several standards identified in the proposal as possible subjects
for revision have not been amended in this final rule. Section 75.400-
2, which requires the establishment of a cleanup program for the
removal of accumulations prohibited under Sec. 75.400, has not been
specifically amended to include the term ``diesel-powered equipment.''
Existing Sec. 75.400-2 does not make reference to a particular type of
equipment, either diesel- or electric-powered. The standard simply
requires that a program be established for the cleanup and removal of
combustible materials. Therefore, Sec. 75.400-2 already applies to
diesel-powered equipment and amending the standard is unnecessary.
MSHA also solicited comments in the proposed rule on whether the
requirements of Secs. 75.523, 75.523-1 and 75.523-2 should be applied
to diesel-powered equipment. These standards protect equipment
operators from pinning and crushing injuries by requiring self-
propelled electric face equipment to be equipped with panic bars, which
quickly deenergize the tramming motors in the event of an emergency.
The existing standards do not require panic bars if the equipment is
provided with a substantially constructed cab or canopy in accordance
with Sec. 75.1710-1, or if other devices approved by MSHA are installed
to quickly deenergize the tramming motor in the event of an emergency.
Because Secs. 75.523, 75.523-1, and 75.523-2 make specific
reference to the interrelationship among electric motors, electrical
control components, cabs, emergency parking brakes, and panic bars,
these standards cannot be readily adapted to diesel-powered equipment.
An MSHA study of diesel-powered face equipment accidents occurring from
1984 to 1995 found that this type of equipment is manufactured with a
substantially constructed operator's compartment which provides the
same protection as a cab. The study also found no pinning or crushing
accidents of the type that would have been prevented by a panic bar on
diesel equipment. Since this type of diesel equipment will be evaluated
under part 36, the approval process can ensure that the protection
features provided on diesel equipment will provide at least the same
protection as that provided by a panic bar on electrical equipment. The
final rule, therefore, does not amend Sec. 75.523 to require panic bars
or the equivalent on diesel-powered equipment.
The proposed rule also solicited comment on the applicability of
existing Sec. 75.1107-1, which requires fire suppression devices on
certain attended and unattended underground electric equipment, to
diesel-powered equipment. The fire hazards presented by diesel-powered
equipment are different from those on electric-powered equipment, due
to the close proximity of large quantities of hydraulic oils and fuels
to the heated diesel engine exhaust. Because effective fire suppression
systems are essential for the safe operation of diesel-powered
equipment, specific requirements for fire suppression systems on
diesel-powered equipment are addressed in the final rule at
Sec. 75.1911.
Derivation Table
The following table lists final standard section numbers and
corresponding section numbers of existing standards from which they are
derived.
------------------------------------------------------------------------
New sections Existing sections
------------------------------------------------------------------------
Part 7--Subpart E......................... New, Parts 7, 32, 36
7.81...................................... New
7.82...................................... New, 36.2, 7.2
7.83...................................... New, 36.6, 7.3
7.84...................................... New, 32.4(f), 36.26(b),
36.44, 75.322
7.85 through 7.87......................... New
7.88...................................... New, 75.322
7.89...................................... New
7.90...................................... New, 36.11
7.91 and 7.92............................. New
Part 7--Subpart F......................... New, Parts 7, 18, 36
7.95...................................... New
7.96...................................... New, 36.2, 7.2
7.97...................................... New, 36.6, 7.3
7.98...................................... New, Part 36--Subpart B
7.99...................................... New
7.100 and 7.101........................... New, 36.46
7.102 and 7.103........................... New, 36.47
7.104..................................... New, 36.46
7.105..................................... New, 7.6, 36.11
7.106..................................... New, 7.8(b)
7.107..................................... New, 7.52
7.108 and 7.109........................... New
Part 36................................... Partly new, Part 31
36.1...................................... Partly new
36.2(e)................................... Partly new
36.2(f)................................... Partly new, 36.2(h)
36.6 (b)(2) through (b)(4)................ Partly new
36.9(a)................................... Partly new
36.20(b).................................. Partly new
36.20(c).................................. New
36.21..................................... Partly new
36.43(a).................................. Partly new
36.48(b).................................. Partly new
70.1900(a)................................ New, 75.100, 75.362
70.1900 (a)(1) through (b)(3)............. New
70.1900(c)................................ New, 75.322, 75.325(j)
[[Page 55499]]
70.1900(d)................................ New, 75.363
70.1900 (d)(1) through (e)................ New
75.325 (f) through (h).................... New, Part 32
75.325 (i) and (j)........................ New, Part 32, 75.322
75.325(k)................................. New, Part 32, 75.371
75.342 (b)(2) and (c)..................... Partly new
75.360(b)(7).............................. Partly new
75.371(r)................................. Partly new
75.371 (kk) through (oo).................. New
75.371(pp)................................ New, 75.322
75.400.................................... Partly new
75.1710 and 75.1710-1..................... Partly new
Part 75--Subpart T........................ New, Part 32
75.1900................................... New, 75.301
75.1901(a)................................ New, 36.2(i)
75.1901(b)................................ New
75.1901(c)................................ New, 40 CFR 79
75.1902................................... New
75.1903(a)(1)............................. New, 75.301, 75.340
75.1903 (a)(2) and (a)(3)................. New
75.1903(a)(4)............................. New, 75.333(e), 75.340
75.1903 (a)(5) through (a)(7)............. New
75.1903(b)(1)............................. New, 75.1100-2(f)
75.1903 (b)(2) through (d)(6)............. New
75.1904................................... New
75.1905................................... New
75.1906 (a) through (f)................... New
75.1906(g)................................ New, 75.1107-3 through
75.1107-6, 75.1107-8
through 75.1107-16
75.1906 (h) and (i)....................... New
75.1906(j)................................ New, 75.1000-3
75.1906 (k) and (l)....................... New
75.1907................................... New
75.1908................................... New
75.1909 (a)(1) through (a)(3)(i).......... New
75.1909 (a)(3)(ii)........................ New, 36.27(a)(1)
75.1909 (a)(3)(iii) through (a)(3)(ix).... New
75.1909 (a)(3)(x)......................... New, 36.27(c)
75.1909 (a)(3)(xi) through (b)(3)......... New
75.1909(b)(4)............................. New, 36.28
75.1909(b)(5)............................. New, 36.33(b)
75.1909 (b)(6) through (b)(8)............. New, 36.29
75.1909(c)................................ New, 75.523-3, 75.1404,
75.1404-1
75.1909(c)(1)............................. New, 75.523-3(b)(2)
75.1909(c)(2)............................. New, 75.523-3(b)(3)
75.1909(c)(3)............................. New, 75.523-3(b)(4)
75.1909(c)(4)............................. New, 75.523-3(b)(5)
75.1909(c)(5)............................. New, 75.523-3(c)
75.1909(c)(6)............................. New
75.1909(d)................................ New, 75.523-3(d)
75.1909(e)................................ New, 75.523-3(e)
75.1909(f)................................ New, 36.29
75.1909 (g) through (j)................... New
75.1910(a)................................ New, 75.518, 75.518-1
75.1910 (b) through (e)................... New
75.1910(f)................................ New, 75.513, 75.513-1
75.1910 (g) and (h)....................... New, 75.515
75.1910(i)................................ New, 75.514
75.1910(j)................................ New
75.1910(k)................................ New, 7.44(a)(1)
75.1910(l)................................ New, 7.44 (d), (e), and (m)
75.1910(m)................................ New, 7.44(f)
75.1910(n)................................ New, 7.44(h)
75.1910(o)................................ New, 7.44(g)
75.1911 (a) through (k)................... New
75.1911(l)................................ New, 75.380(f), 75.1107-3
through 75.1107-16
75.1912(a)(1)............................. New, 75.1107-13
75.1912 (a)(2) through (b)................ New
75.1912(c)................................ New, 75.1101-23
75.1912(d)................................ New, 75.1107-4
75.1912 (e) through (g)................... New
75.1912(h)................................ New, 75.1107-16
75.1912(i)................................ New
75.1912(j)................................ New, 75.1101-23
75.1913................................... New
75.1914................................... New
75.1915................................... New
75.1916(a)................................ New, 75.380(d), 75.1403
75.1916 (b) through (e)................... New
------------------------------------------------------------------------
Distribution Table
The following table lists section numbers of existing standards
which contain provisions that were used in the development of the
listed final standards.
------------------------------------------------------------------------
Existing sections New sections
------------------------------------------------------------------------
7.2....................................... 7.82, 7.96
7.3....................................... 7.83, 7.97
7.6....................................... 7.105
7.8(b).................................... 7.106
7.44(a)(1)................................ 75.1910(k)
7.44 (d) and (e).......................... 75.1910(l)
7.44(f)................................... 75.1910(m)
7.44(g)................................... 75.1910(o)
7.44(h)................................... 75.1910(n)
7.44(m)................................... 75.1910(l)
7.44(a)(1)................................ 75.1910(k)
7.52...................................... 7.107
Part 31................................... Part 36
Part 32................................... Part 7--Subpart E, 75.325
(f) through (k), and Part
75--Subpart T
32.4(f)................................... 7.84
Part 36--Subpart B........................ 7.98
36.2...................................... 7.82, 7.96
36.2(h)................................... 36.2(f)
36.2(i)................................... 75.1901(a)
36.6...................................... 7.83, 7.97
36.11..................................... 7.90, 7.105
36.26(b).................................. 7.84
36.27(a)(1)............................... 75.1909(a)(3)(ii)
36.27(c).................................. 75.1909(a)(3)(x)
36.28..................................... 75.1909(b)(4)
36.29..................................... 75.1909 (b)(6) through
(b)(8) and (f)
36.33(b).................................. 75.1909(b)(5)
36.44..................................... 7.84
36.46..................................... 7.100, 7.101, 7.104
36.47..................................... 7.102, 7.103
75.100.................................... 70.1900(a)
75.301.................................... 75.1900, 75.1903(a)(1)
75.322.................................... 7.84, 7.88, 70.1900(c),
75.325 (i) and (j),
75.371(pp)
75.325 (g) and (i)........................ 75.371(r)
75.325(j)................................. 70.1900(c)
75.333(e)................................. 75.1903(a)(4)
75.340.................................... 75.1903 (a)(1) and (a)(4)
75.362.................................... 70.1900(a)
75.363.................................... 70.1900(d)
75.371.................................... 75.325(k)
75.380(d)................................. 75.1916(a)
75.380(f)................................. 75.1911(l)
75.513 and 75.513-1....................... 75.1910(f)
75.514.................................... 75.1910(i)
75.515.................................... 75.1910 (g) and (h)
75.518 and 75.518-1....................... 75.1910(a)
75.523-3.................................. 75.1909(c)
75.523-3(b)(2)............................ 75.1909(c)(1)
75.523-3(b)(3)............................ 75.1909(c)(2)
75.523-3(b)(4)............................ 75.1909(c)(3)
75.523-3(b)(5)............................ 75.1909(c)(4)
75.523-3(c)............................... 75.1909(c)(5)
75.523-3(d)............................... 75.1909(d)
75.523-3(e)............................... 75.1909(e)
75.1000-3................................. 75.1906(j)
75.1100-2(f).............................. 75.1903(b)(1)
75.1101-23................................ 75.1912 (c) and (j)
75.1107-3 through 75.1107-16.............. 75.1911(l)
75.1107-3 through 75.1107-6 and 75.1107-8 75.1906(g)
through 75.1107-16.
75.1107-4................................. 75.1912(d)
75.1107-13................................ 75.1912(a)(1)
75.1107-16................................ 75.1912(h)
75.1403................................... 75.1916(a)
75.1404 and 75.1404-1..................... 75.1909(c)
40 CFR 79................................. 75.1901(c)
------------------------------------------------------------------------
III. Paperwork Reduction Act
The information collection requirements contained in this rule have
been submitted to the Office of Management and Budget (OMB) for review
under the Paperwork Reduction Act of 1995 (44 U.S.C. 3501-3520), as
implemented by OMB in regulations at 5 CFR 1320. No person may be
required to respond to, or may be subjected to a penalty for failure to
comply with, these information collection requirements until they have
been approved by OMB and MSHA has displayed the assigned OMB control
number. The OMB control number, when assigned, will be announced by
separate notice in the Federal Register.
[[Page 55500]]
The final rule addresses comments submitted to OMB and MSHA on the
collection of information requirements in the proposed rule in the
section-by-section discussions. In revising the requirements from those
that appeared in the proposed rule, MSHA has evaluated the necessity
and usefulness of the collection of information; reevaluated MSHA's
estimate of the information collection burden, including the validity
of the underlying methodology and assumptions; and minimized the
information collection burden on respondents to the extent possible.
This final rule also provides for the use of electronic storage and
maintenance of records.
Tables 1 through 4 show the distribution of information collection
burden hours imposed by the requirements of the final rule. Tables 1
and 2 pertain to manufacturers, Table 3 pertains to small mine
operators, and Table 4 pertains to large mine operators.
Table 1.--Estimated Annual New Burden Related to Manufacturers
--------------------------------------------------------------------------------------------------------------------------------------------------------
Operating
Number of Capital and
Detail Number of Hours per Number of responses costs maintenance Total hours
respondents response responses per annualized costs
respondent (rounded) (rounded)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Part 7--Subpart E
New Eng. (Perm.) \1\...................................... 1.5 43 1.5 1 $0 $0 65
New Eng. (Perm.) \2\...................................... 1.5 0.5 1.5 1 0 75 1
New Eng. (Nonperm.) \3\................................... 2.5 34 2.5 1 0 0 85
New Eng. (Nonperm.) \4\................................... 2.5 0.5 2.5 1 0 100 1
Existing Eng. (Nonperm.) \5\.............................. 16 5 16 1 425 0 80
New Eng. (Nonperm.) \6\................................... 1 34.5 1 1 0 2,600 35
Existing Eng. (Nonperm.) \7\.............................. 1 34.5 1 1 200 0 35
7.90...................................................... 148 0.1667 148 1 0 450 24
Part 7--Subpart F
New Pow. Pack. (Perm.) \8\................................ 1.5 43 1.5 1 0 0 65
Existing Pow. Pack. (Perm.) \9\........................... 33 12 33 1 2,100 0 396
7.105..................................................... 20 0.1667 20 1 0 75 3
---------------------------------------------------------------------------------------------
Total Increases....................................... ............ ............ ............ ........... 2,725 3,300 790
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ New diesel-powered engine models used in permissible equipment will require a maximum fuel:air ratio test and a gaseous ventilation rate test under
part 7, subpart E, instead of under existing part 36. Burden hours are shifted from existing part 36 to part 7, subpart E. The annual estimated
application costs of $4,850 are currently being incurred by manufacturers under part 36. Under the final rule, such costs will continue to be incurred
under part 7, subpart E, instead of under part 36. There are no new compliance costs.
\2\ New diesel-powered engine models used in permissible equipment that would have received part 36 approval will require a particulate index test.
\3\ New diesel-powered engine models used in nonpermissible equipment that would have received part 32 approval will require a maximum fuel air ratio
test and a gaseous ventilation rate test under part 7, subpart E, instead of under part 32. As a result of this rule, part 32 is deleted and burden
hours related to the tests on such engine models are shifted from deleted part 32 to part 7, subpart E. The annual estimated application costs of
$6,375 are currently being incurred by manufacturers under part 32. Under the final rule, such costs will continue to be incurred under part 7,
subpart E, instead of under part 32. There are no new compliance costs.
\4\ New diesel-powered engine models used in nonpermissible equipment that would have received part 32 approval will require a particulate index test.
\5\ Existing diesel-powered engine models used in nonpermissible equipment that have part 32 approval will require a one time particulate index test.
\6\ New diesel-powered engine models used in nonpermissible equipment that would not have received part 32 approval will require a maximum fuel air
ratio test, a gaseous ventilation rate test, and a particulate index test.
\7\ Existing diesel-powered engine models used in nonpermissible equipment that do not have part 32 approval will require a one time maximum fuel air
ratio test, a gaseous ventilation rate test, and a particulate index test.
\8\ New diesel-power package models used in permissible equipment will require approval under part 7, subpart F, instead of under part 36. Burden hours
related to such approvals are shifted from part 36 to part 7, subpart F. The annual estimated application costs of $4,850 are currently being incurred
by manufacturers under part 36. Under the final rule, such costs will continue to be incurred under part 7, subpart F, instead of under part 36. There
are no new compliance costs.
\9\ Diesel-power package models used in permissible equipment and previously approved under part 36 could be reapproved and used to comply with the
requirement for a diesel power package pursuant to part 7, subpart F.
Table 2.--Estimated Annual Decrease in Burden Related to Manufacturers \1\
--------------------------------------------------------------------------------------------------------------------------------------------------------
Number of Operation
Number of Hours per Number of responses Capital and
Detail respondents response responses per costs maintenance Total hours
respondent annualized costs
--------------------------------------------------------------------------------------------------------------------------------------------------------
Part 36
New Eng. (Perm.) \2\...................................... 1.5 43 1.5 1 $0 $0 65
New Pow. Pack. (Perm.) \3\................................
1.5 43 1.5 1 0 0 65
Part 32
New Eng. (Nonperm.) \4\................................... 2.95 34.5 2.95 1 0 0 102
---------------------------------------------------------------------------------------------
Total Decreases....................................... ............ ............ ............ ........... ........... ........... 232
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Burden hours in this chart were developed and approved under the Paperwork Reduction Act of 1980 (PRA 80). PRA 80 did not require costs to be
reported with burden hours. Thus no compliance costs are noted in this table.
\2\ New diesel-powered engine models used in permissible equipment will be approved under part 7, subpart E, instead of part 36.
\3\ Diesel-power package models used in permissible equipment will be approved under part 7, subpart F, instead of part 36.
[[Page 55501]]
\4\ New diesel-powered engine models used in nonpermissible equipment will be approved under part 7, subpart E, instead of part 32.
Table 3.-- Estimated Annual New Burden for Small Underground Coal Operators That Use Diesel-Powered Equipment \1\
--------------------------------------------------------------------------------------------------------------------------------------------------------
Operation
Number of Capital and
Detail Number of Hours per Number of responses costs maintenance Total hours
respondents response responses per annualized costs
\2\ respondent (rounded) (rounded)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Sec. 75.363............................................. 10 0.10 100 10 $2,100 $3,800 10
Sec. 75.370............................................. 15 0.1667 15 1 0 100 3
Sec. 75.1901(a)......................................... 8 0.05 160 20 0 100 8
Sec. 75.1904(b)(4)(i)................................... 15 0.0333 20 1 <25 0 1
Sec. 75.1911 (i)&(j) \3\................................ 15 0.3333 212 14 0 1,835 71
Sec. 75.1911 (i)&(j) \4\................................ 15 1.0833 11 <1 0 915 12
Sec. 75.1912 (h)&(i) \5\................................ 15 0.5833 20 1 0 300 12
Sec. 75.1912 (h)&(i) \6\................................ 15 1.0833 2 <1 0 100 2
Sec. 75.1914 (f)(1)&(h)................................. 15 \7\ 1.1857 500 33 0 15,400 593
Sec. 75.1914 (f)(2)&(h)................................. 15 0.0833 500 33 0 1,100 42
Sec. 75.1914(g)&(h) \8\................................. 15 2 30 2 150 0 60
Sec. 75.1914 (g)&(h) \9\................................ 1 2 1 1 0 50 2
Sec. 75.1914 (g)(5)&(h)................................. 15 0.25 1,480 98 3,150 16,650 370
Sec. 75.1915(a)......................................... 15 5 30 2 400 0 150
Sec. 75.1915 (b)(5)&(c) \8\............................. 15 10 15 1 400 0 150
Sec. 75.1915 (b)(5)&(c) \9\............................. 1 3 1 1 0 125 3
----------------------------------------------------------------------------------------------
Total................................................ .............. ............ ........... ........... 6,225 40,475 1,489
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Small mines are those that employ 19 or fewer people.
\2\ Respondents are the number of small mines.
\3\ Section 75.1911(j) requires a record of Sec. 75.1911(i) weekly exams which find defects.
\4\ Section 75.1911(j) requires a record of Sec. 75.1911(i) manufacturer recommended exams which find defects.
\5\ Section 75.1912(i) requires a record of Sec. 75.1912(h) weekly exams which find defects.
\6\ Section 75.1912(i) requires a record of Sec. 75.1912(h) manufacturer recommended exams which find defects.
\7\ Represents a weighted average of hours based upon different exam hours for different types of equipment.
\8\ Reflects burden hours that will occur in the first year of implementation of the provision.
\9\ Reflects burden hours that will occur annually, after the first year of implementation of the provision.
Table 4.--Estimated Annual New Burden for Large Underground Coal Operators That Use Diesel-Powered Equipment 1
--------------------------------------------------------------------------------------------------------------------------------------------------------
Operating
Number of Capital and
Detail Number of Hours per Number of responses costs maintenance Total hours
respondent responses responses per annualized costs
2 respondent (rounded) (rounded)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Sec. 75.363................................................ 100 0.1834 1,000 10 $20,950 $40,825 184
Sec. 75.370................................................ 158 0.3333 158 1 0 1,975 52
Sec. 75.1901(a)............................................ 79 0.05 1,975 25 0 1,000 99
Sec. 75.1904(b)(4)(i)...................................... 158 0.0333 494 3 250 0 16
Sec. 75.1911 (i) & (j) 3................................... 158 0.3333 14,810 94 0 128,340 4,936
Sec. 75.1911 (i) & (j) 4................................... 158 1.0833 592 4 0 51,335 641
Sec. 75.1912 (h) & (i) 5................................... 158 0.5833 100 <1 0 1,525 58
Sec. 75.1912 (h) & (i) 6................................... 158 1.0833 4 <1 0 350 5
Sec. 75.1914 (f)(1) & (h).................................. 158 7 0.6234 35,975 227 0 583,150 22,428
Sec. 75.1914 (f)(2) & (h).................................. 158 0.0833 35,975 227 0 77,925 2,997
Sec. 75.1914 (g) & (h) 8................................... 158 2 711 4 3,725 0 1,422
Sec. 75.1914 (g) & (h) 9................................... 5 2 22.5 4 0 1,700 45
Sec. 75.1914 (g)(5) & (h).................................. 158 0.25 52,350 331 33,100 460,225 13,088
Sec. 75.1915(a)............................................ 158 5 1,264 8 0 236,000 6,320
Sec. 75.1915 (b)(5) & (c) 8................................ 158 16 158 1 6,600 0 2,528
Sec. 75.1915 (b)(5) & (c) 9................................ 5 16 5 1 0 3,000 80
-------------------------------------------------------------------------------------------
Total................................................... ........... ............ ........... ........... 64,625 1,587,350 54,899
--------------------------------------------------------------------------------------------------------------------------------------------------------
1 Large mines are those that employ 20 or more people.
2 Respondents are the number of large mines.
3 Section 75.1911(j) requires a record of Sec. 75.1911(i) weekly exams which find defects.
4 Section 75.1911(j) requires a record of Sec. 75.1911(i) manufacturer recommended exams which find defects.
5 Section 75.1912(i) requires a record of Sec. 75. 1912(h) weekly exams which find defects.
6 Section 75.1912(i) requires a record of Sec. 75. 1912(h) manufacturer recommended exams which find defects.
7 Represents a weighted average of hours based upon different exam hours for different types of equipment.
8 Reflects burden hours that will occur in the first year of implementation of the provision.
9 Reflects burden hours that will occur annually, after the first year of implementation of the provision.
[[Page 55502]]
IV. Executive Order 12866 and Regulatory Flexibility Analysis
Under E.O. 12866 [58 FR 51735, October 4, 1993] the Agency must
determine whether the regulatory action is ``significant'' and subject
to OMB review.
E.O. 12866 defines ``significant regulatory action'' as one that is
likely to result in a rule that may: (1) Have an annual effect on the
economy of $100 million or more or adversely affect in a material way
the economy, a sector of the economy, productivity, competition, jobs,
the environment, public health or safety, or state, local, or tribal
governments or communities; (2) create a serious inconsistency or
otherwise interfere with an action taken or planned by another agency;
(3) materially alter the budgetary impact of entitlements, grants, user
fees, or loan programs or the right and obligations of recipients
thereof; or (4) raise novel legal or policy issues arising out of legal
mandates, the President's priorities, or the principles set forth in
the Executive Order.
OMB determined that this rule for diesel-powered equipment in
underground coal mines is a ``significant regulatory action'' because
MSHA's diesel particulate rulemaking for all mines has been designated
``significant'' by the Agency. Although the diesel particulate
rulemaking is separate and distinct from this final rule, OMB concluded
that there is a sufficient enough relationship with this final rule to
warrant its designation as significant. As such, MSHA has submitted
this final rule to OMB for review.
As required by E.O. 12866, the Agency determined costs and benefits
associated with this final rule and has prepared a Final Regulatory
Impact Analysis (RIA) and a Final Regulatory Flexibility Analysis
(RFA). The RFA assesses benefits and costs of, and potentially
effective and reasonably feasible alternatives to, the planned
regulatory action. The RIA and RFA are available electronically and on
request from MSHA through the address listed in the contact section at
the beginning of this document. It is summarized below.
Benefits
The final rule establishes comprehensive and integrated
requirements governing diesel-powered equipment used in underground
coal mines. Compliance with the rule will minimize fire, explosion,
fuel handling, and fuel storage hazards. The health hazards of diesel
engine exhaust are addressed by design, performance, and maintenance
standards for diesel engines. Other safety hazards associated with the
use of diesel-powered equipment in underground coal mines are also
addressed.
The final rule includes tests and specifications for MSHA approval
of diesel engines. Clean operating engines will reduce miners' exposure
to harmful emissions in the confined underground mine environment. The
final rule sets test procedures and limits on the concentrations of
carbon monoxide and oxides of nitrogen, and establishes the quantity of
ventilating air necessary to dilute these exhaust contaminants to safe
levels. The rule also contains tests and specifications for approval of
diesel engine components, to ensure that diesel engines are fire and
explosion-proof.
The final rule also requires diesel-powered equipment to be
equipped with certain safety features. These safety features will
result in reduced fire hazards and lower the risk of accidents
involving diesel-powered equipment. For example, the final rule
requires diesel-powered equipment to have basic safety features, such
as brakes and lights; fire protection features, including fuel,
hydraulic, and electrical system protections; and properly designed,
installed, and maintained fire suppression systems. In addition, the
rule extends to diesel-powered equipment safety measures that already
apply to electric-powered equipment that are proven to protect miners
from cave-ins, such as cabs and canopies, and from explosions, such as
methane monitors.
The final rule provides for a systematic approach to the clean and
safe operation of diesel-powered equipment. To accomplish this, the
final rule sets standards for ventilation of diesel-powered equipment,
and for routine sampling of toxic exhaust gases in the workplace, and
requires the use of low sulfur diesel fuel to minimize emissions. It
also requires that maintenance be performed by trained personnel to
keep diesel equipment in proper operating condition.
To ensure that the hazards associated with diesel fuel usage in the
underground mine environment are properly controlled, the final rule
includes requirements for the underground storage, transportation, and
dispensing of diesel fuel. Design, tank capacity, and dispensing
requirements are set for diesel fuel storage, as well as safety
precautions and construction requirements for underground storage
facilities and areas, including automatic fire suppression systems.
These provisions will reduce the risk of fires involving diesel fuel.
The final rule also extends several longstanding safety
requirements for electric equipment to diesel-powered equipment. The
final rule requires certain diesel equipment to be installed with
methane monitors, providing miners with critical protection against
methane explosions. The final rule also requires cabs and canopies to
be installed on certain diesel-powered equipment, protecting miners
from the dangers of roof and rib falls in the underground mine
environment.
Cost of Compliance
The compliance costs associated with the standards directly impact
two industry groups: manufacturers of diesel-powered mining equipment
and operators of underground coal mines. Part 7, subparts E and F
relate to manufacturer costs and parts 70 and 75 relate to operator
costs. The total compliance costs of the rule are estimated to be about
$10.35 million per year, of which mine operators will incur about $10.3
million per year and manufacturers will incur about $50,000 per year.
The per-year cost of $10.3 million for mine operators consists of
$4.9 million of annualized cost plus $5.4 million of annual costs. Of
the $10.3 million, large mine operators will incur about $10.1 million,
which consists of $4.8 million of annualized costs and $5.3 million of
annual costs. Of the $10.3 million, small mine operators will incur
about $210,800, which consists of $92,300 of annualized costs and
$118,500 of annual costs. The per-year compliance costs for large and
small mine operators is shown by section in Table 5.
Manufacturers will incur costs of approximately $50,450 per year.
The $50,450 consists of $15,900 of annualized costs and $34,550 of
annual costs. The per-year compliance costs for manufacturers is shown
by section in Table 6.
[[Page 55503]]
Table 5.--Underground Coal Mine Compliance Costs for Diesel Equipment
[Dollars x 1,000]
--------------------------------------------------------------------------------------------------------------------------------------------------------
Large and small mines Large mines Small mines
---------------------------------------------------------------------------------------------------------
Standard (G) total
(A) total (B) (C) (D) total (E) (F) [Col. (H) (I)
[col. B+C] annualized annual [col. E+F] annualized annual H+I] annualized annual
--------------------------------------------------------------------------------------------------------------------------------------------------------
70.1900....................................... ($59.7) $80.9 ($140.6) ($77.7) $75.8 ($153.5) $18.0 $5.1 $12.9
75.325........................................ 589.0 0 589.0 589.0 0 589.0 0 0 0
75.1902....................................... 39.7 39.7 0 37.6 37.6 0 2.1 2.1 0
75.1903....................................... 68.5 51.5 17.0 58.2 44.7 13.5 10.3 6.8 3.5
75.1904....................................... 32.7 32.7 0 31.2 31.2 0 1.5 1.5 0
75.1905....................................... 2.4 2.4 0 2.3 2.3 0 0.1 0.1 0
75.1906....................................... 251.8 173.5 78.3 244.7 168.8 75.9 7.1 4.7 2.4
75.1907....................................... 1,610.3 1,596.6 13.7 1,589.6 1,576.4 13.2 20.7 20.2 0.5
75.1909....................................... 3,028.0 2,532.9 495.1 2,971.2 2,487.6 483.6 56.8 45.3 11.5
75.1910....................................... 117.4 117.4 0 116.1 116.1 0 1.3 1.3 0
75.1911....................................... 1,221.3 0 1,221.3 1,203.2 0 1,203.2 18.1 0 18.1
75.1912....................................... 20.0 0 20.0 16.5 0 16.5 3.5 0 3.5
75.1913....................................... 9.5 9.5 0 9.4 9.4 0 0.1 0.1 0
75.1914....................................... 2,769.3 40.1 2,729.2 2,700.0 36.8 2,663.2 69.3 3.3 66.0
75.1915....................................... 573.9 155.4 418.5 572.3 153.9 418.4 1.6 1.5 0.1
75.1916....................................... 8.7 8.7 0 8.4 8.4 0 0.3 0.3 0
---------------------------------------------------------------------------------------------------------
Total................................... 10,282.8 4,841.3 5,441.5 10,072.0 4,749.0 5,323.0 210.8 92.3 118.5
--------------------------------------------------------------------------------------------------------------------------------------------------------
Table 6.--Estimated Manufacturers Compliance Costs Associated With the
Regulations for Diesel-Powered Equipment in Underground Coal Mines
------------------------------------------------------------------------
Manufacturers costs
--------------------------------------
Standard (A) total (B)
[col. B+C] annualized (c) annual
------------------------------------------------------------------------
Part 7--Subpart E................ $42,650 $12,200 $30,450
Part 7--Subpart F................ 7,800 3,700 4,100
--------------------------------------
Total Part 7............... 50,450 15,900 34,550
------------------------------------------------------------------------
Regulatory Flexibility Certification
The Regulatory Flexibility Act requires that agencies developing
regulatory standards evaluate and, where possible, include compliance
alternatives that minimize any impact that would adversely affect small
businesses. The use of diesel-powered equipment presents similar health
and safety hazards in both large and small mining operations, and small
mines will benefit from the requirements in the final rule. MSHA,
therefore, has not exempted small mines from any provision of the final
rule.
Regulatory relief is not warranted because the final rule will not
impose a substantial cost increase for small mines. MSHA has determined
that these provisions will not have a significantly adverse impact upon
a substantial number of small entities.
Small Business Regulatory Enforcement Fairness Act
MSHA has determined that this final rule is not a ``major rule''
requiring prior approval by the Congress and the President under the
Small Business Regulatory Enforcement Act of 1996 (5 U.S.C. Sec. 801 et
seq.) (SBREFA), because it is not likely to result in: (1) an annual
effect on the economy of $100 million or more; (2) a major increase in
costs or prices for consumers, individual industries, federal, state,
or local government agencies, or geographic regions; or (3) significant
adverse effects on competition, employment, investment, productivity,
innovation, or on the ability of United States-based enterprises to
compete with foreign enterprises in domestic and export markets.
The Agency will send copies of the final rule, preamble, and
regulatory flexibility analysis to the President of the Senate, the
Speaker of the House, and the General Counsel of the General Accounting
Office.
V. Unfunded Mandates Reform Act of 1995
Title II of the Unfunded Mandates Reform Act of 1995, Pub.L. 104-4,
requires each federal agency to assess the effects of federal
regulatory actions on state, local, and tribal governments and the
private sector, other than to the extent such actions merely
incorporate requirements specifically set forth in a statute. For
purposes of the Unfunded Mandates Reform Act of 1995, as well as E.O.
12875, this rule does not include any federal mandate that may result
in increased expenditures by either State, local, and tribal
governments, or increased expenditures by the private sector of more
than $100 million on the private sector.
VI. Electronic Availability of Rulemaking Documents
Electronic copies of the preamble and final rule, and the
Regulatory Impact Analysis and Regulatory Flexibility Analysis are
available on the Internet at the U.S. Department of Labor, Mine Safety
and Health Administration's World Wide Web home page at http://
www.msha.gov. Instructions for accessing regulatory documents and
information are as follows:
From MSHA's home page select the menu item entitled ``Statutory and
Regulatory Information.'' This will direct the search to the Statutory
and Regulatory menu page. Then select the menu item entitled ``Federal
Register Documents.'' This will direct the search
[[Page 55504]]
to the menu page for Federal Register Documents. The type of documents
listed are proposed rules, final rules, meetings (Advisory Committees),
Information Collection Requests, petitions for modifications, proposed
policies, and miscellaneous notices. Select the menu item desired. To
return to MSHA's home page, use the icon at the bottom of the page or
the ``Back Button'' provided by your browser.
List of Subjects
30 CFR Part 7
Diesel-powered equipment, Mine safety and health, Reporting and
recordkeeping requirements.
30 CFR Parts 31 and 32
Reporting and recordkeeping requirements, Research, Underground
coal mines.
30 CFR Part 36
Mine safety and health.
30 CFR Parts 70 and 75
Diesel-powered equipment, Incorporations by reference, Mine safety
and health, Underground coal mines, Reporting and recordkeeping
requirements.
Dated: October 15, 1996.
J. Davitt McAteer,
Assistant Secretary for Mine Safety and Health.
Accordingly, chapter I of title 30, Code of Federal Regulations is
amended as follows:
PART 7--TESTING BY APPLICANT OR THIRD PARTY
1. The authority citation for part 7 continues to read as follows:
Authority: 30 U.S.C. 957.
2. New subparts E and F are added to part 7 to read as follows:
Subpart E--Diesel Engines Intended for Use in Underground Coal Mines
Sec.
7.81 Purpose and effective date.
7.82 Definitions.
7.83 Application requirements.
7.84 Technical requirements.
7.85 Critical characteristics.
7.86 Test equipment and specifications.
7.87 Test to determine the maximum fuel-air ratio.
7.88 Test to determine the gaseous ventilation rate.
7.89 Test to determine the particulate index.
7.90 Approval marking.
7.91 Post-approval product audit.
7.92 New technology.
Subpart E--Diesel Engines Intended for Use in Underground Coal
Mines
Sec. 7.81 Purpose and effective date.
Subpart A general provisions of this part apply to this subpart E.
Subpart E establishes the specific engine performance and exhaust
emission requirements for MSHA approval of diesel engines for use in
areas of underground coal mines where permissible electric equipment is
required and areas where non-permissible electric equipment is allowed.
It is effective November 25, 1996.
Sec. 7.82 Definitions.
In addition to subpart A definitions of this part, the following
definitions apply in this subpart.
Brake Power. The observed power measured at the crankshaft or its
equivalent when the engine is equipped only with standard auxiliaries
necessary for its operation on the test bed.
Category A engines. Diesel engines intended for use in areas of
underground coal mines where permissible electric equipment is
required.
Category B engines. Diesel engines intended for use in areas of
underground coal mines where nonpermissible electric equipment is
allowed.
Corrosion-resistant material. Material that has at least the
corrosion-resistant properties of type 304 stainless steel.
Diesel engine. Any compression ignition internal combustion engine
using the basic diesel cycle where combustion results from the spraying
of fuel into air heated by compression.
Exhaust emission. Any substance emitted to the atmosphere from the
exhaust port of the combustion chamber of a diesel engine.
Intermediate speed. Maximum torque speed if it occurs between 60
percent and 75 percent of rated speed. If the maximum torque speed is
less than 60 percent of rated speed, then the intermediate speed shall
be 60 percent of the rated speed. If the maximum torque speed is
greater than 75 percent of the rated speed, then the intermediate speed
shall be 75 percent of rated speed.
Low idle speed. The minimum no load speed as specified by the
engine manufacturer.
Maximum torque speed. The speed at which an engine develops maximum
torque.
Operational range. All speed and load (including percent loads)
combinations from the rated speed to the minimum permitted engine speed
at full load as specified by the engine manufacturer.
Particulates. Any material collected on a specified filter medium
after diluting exhaust gases with clean, filtered air at a temperature
of less than or equal to 125 deg. F (52 deg. C), as measured at a point
immediately upstream of the primary filter. This is primarily carbon,
condensed hydrocarbons, sulfates, and associated water.
Percent load. The fraction of the maximum available torque at an
engine speed.
Rated horsepower. The nominal brake power output of a diesel engine
as specified by the engine manufacturer with a specified production
tolerance. For laboratory test purposes, the fuel pump calibration for
the rated horsepower must be set between the nominal and the maximum
fuel tolerance specification.
Rated speed. Speed at which the rated power is delivered, as
specified by the engine manufacturer.
Steady-state condition. Diesel engine operating condition which is
at a constant speed and load and at stabilized temperatures and
pressures.
Total oxides of nitrogen. The sum total of the measured parts per
millions (ppm) of nitric oxide (NO) plus the measured ppm of nitrogen
dioxide (NO2).
Sec. 7.83 Application requirements.
(a) An application for approval of a diesel engine shall contain
sufficient information to document compliance with the technical
requirements of this subpart and specify whether the application is for
a category A engine or category B engine.
(b) The application shall include the following engine
specifications--
(1) Model number;
(2) Number of cylinders, cylinder bore diameter, piston stroke,
engine displacement;
(3) Maximum recommended air inlet restriction and exhaust
backpressure;
(4) Rated speed(s), rated horsepower(s) at rated speed(s), maximum
torque speed, maximum rated torque, high idle, minimum permitted engine
speed at full load, low idle;
(5) Fuel consumption at rated horsepower(s) and at the maximum
rated torque;
(6) Fuel injection timing; and
(7) Performance specifications of turbocharger, if applicable.
(c) The application shall include dimensional drawings (including
tolerances) of the following components specifying all details
affecting the technical requirements of this subpart. Composite
drawings specifying the required construction details may be submitted
instead of individual drawings of the following components--
[[Page 55505]]
(1) Cylinder head;
(2) Piston;
(3) Inlet valve;
(4) Exhaust valve;
(5) Cam shaft--profile;
(6) Fuel cam shaft, if applicable;
(7) Injector body;
(8) Injector nozzle;
(9) Injection fuel pump;
(10) Governor;
(11) Turbocharger, if applicable;
(12) Aftercooler, if applicable;
(13) Valve guide;
(14) Cylinder head gasket; and
(15) Precombustion chamber, if applicable.
(d) The application shall include a drawing showing the general
arrangement of the engine.
(e) All drawings shall be titled, dated, numbered, and include the
latest revision number.
(f) When all necessary testing has been completed, the following
information shall be submitted:
(1) The gaseous ventilation rate for the rated speed and
horsepower.
(2) The particulate index for the rated speed and horsepower.
(3) A fuel deration chart for altitudes for each rated speed and
horsepower.
Sec. 7.84 Technical requirements.
(a) Fuel injection adjustment. The fuel injection system of the
engine shall be constructed so that the quantity of fuel injected can
be controlled at a desired maximum value. This adjustment shall be
changeable only after breaking a seal or by altering the design.
(b) Maximum fuel-air ratio. At the maximum fuel-air ratio
determined by Sec. 7.87 of this part, the concentrations (by volume,
dry basis) of carbon monoxide (CO) and oxides of nitrogen (NOX) in
the undiluted exhaust gas shall not exceed the following:
(1) There shall be no more than 0.30 percent CO and no more than
0.20 percent NOX for category A engines.
(2) There shall be no more than 0.25 percent CO and no more than
0.20 percent NOX for category B engines.
(c) Gaseous emissions ventilation rate. Ventilation rates necessary
to dilute gaseous exhaust emissions to the following values shall be
determined under Sec. 7.88 of this part:
Carbon dioxide......................... -5000 ppm
Carbon monoxide........................ -50 ppm
Nitric oxide........................... -25 ppm
Nitrogen dioxide....................... -5 ppm
A gaseous ventilation rate shall be determined for each requested speed
and horsepower rating as described in Sec. 7.88(b) of this part.
(d) Fuel deration. The fuel rates specified in the fuel deration
chart shall be based on the tests conducted under paragraphs (b) and
(c) of this section and shall ensure that the maximum fuel:air (f/a)
ratio determined under paragraph (b) of this section is not exceeded at
the altitudes specified in the fuel deration chart.
(e) Particulate index. For each rated speed and horsepower
requested, the particulate index necessary to dilute the exhaust
particulate emissions to 1 mg/m3 shall be determined under
Sec. 7.89 of this part.
Sec. 7.85 Critical characteristics.
The following critical characteristics shall be inspected or tested
on each diesel engine to which an approval marking is affixed--
(a) Fuel rate is set properly; and
(b) Fuel injection pump adjustment is sealed, if applicable.
Sec. 7.86 Test equipment and specifications.
(a) Dynamometer test cell shall be used in determining the maximum
f/a ratio, gaseous ventilation rates, and the particulate index.
(1) The following testing devices shall be provided:
(i) An apparatus for measuring torque that provides an accuracy of
2.0 percent based on the engine's maximum value;
(ii) An apparatus for measuring revolutions per minute (rpm) that
provides an accuracy of 2.0 percent based on the engine's
maximum value;
(iii) An apparatus for measuring temperature that provides an
accuracy of 4 deg. F (2 deg. C) of the absolute value
except for the exhaust gas temperature device that provides an accuracy
of 27 deg. F (15 deg. C);
(iv) An apparatus for measuring intake and exhaust restriction
pressures that provides an accuracy of 5 percent of
maximum;
(v) An apparatus for measuring atmospheric pressure that provides
an accuracy of 0.5 percent of reading;
(vi) An apparatus for measuring fuel flow that provides an accuracy
of 2 percent based on the engine's maximum value;
(vii) An apparatus for measuring the inlet air flow rate of the
diesel engine that provides an accuracy of 2 percent based
on the engine's maximum value; and
(viii) For testing category A engines, an apparatus for metering in
1.0 0.1 percent, by volume, of methane (CH4) into the
intake air system shall be provided.
(2) The test fuel specified in Table E-1 shall be a low volatile
hydrocarbon fuel commercially designated as ``Type 2-D'' grade diesel
fuel. The fuel may contain nonmetallic additives as follows: Cetane
improver, metal deactivator, antioxidant, dehazer, antirust, pour
depressant, dye, dispersant, and biocide.
Table E-1.--Diesel Test Fuel Specifications
------------------------------------------------------------------------
Item ASTM Type 2-D
------------------------------------------------------------------------
Cetane number.................. D613 40-48.
Cetane index................... D976 40-48.
Distillation range:
IBP deg.F................. D86 340-400.
( deg.C)............... ............... (171.1-204.4).
10 pct. point, deg.F...... D86 400-460.
( deg.C)............... ............... (204.4-237.8).
50 pct. point, deg.F...... D86 470.540.
( deg.C)............... ............... (243.3-282.2).
90 pct. point, deg.F...... D86 560-630.
( deg.C)............... ............... (293.3-332.2).
EP, deg.F................. D86 610-690.
( deg.C)............... ............... (321.1-365.6).
Gravity, deg.API.............. D287 32-37.
Total sulfur, pct.............. D2622 0.03-0.05.
Hydrocarbon composition:
Aromatics, pct............. D1319 27 minimum.
Paraffins, naphthenes, D1319 Remainder.
olefins.
[[Page 55506]]
Flashpoint, minimum, deg.F.... 93 130.
( deg.C)................... ............... (54.4).
Viscosity, centistokes......... 445 2.0-3.2.
------------------------------------------------------------------------
(3) The test fuel temperature at the inlet to the diesel engine's
fuel injection pump shall be controlled to the engine manufacturer's
specification.
(4) The engine coolant temperature (if applicable) shall be
maintained at normal operating temperatures as specified by the engine
manufacturer.
(5) The charge air temperature and cooler pressure drop (if
applicable) shall be set to within 7 deg. F(4 deg. C) and
0.59 inches Hg (2kPa) respectively, of the manufacturer's
specification.
(b) Gaseous emission sampling system shall be used in determining
the gaseous ventilation rates.
(1) The schematic of the gaseous sampling system shown in Figure E-
1 shall be used for testing category A engines. Various configurations
of Figure E-1 may produce equivalent results. The components in Figure
E-1 are designated as follows--
(i) Filters--F1, F2, F3, and F4;
(ii) Flowmeters--FL1, FL2, FL3, FL4, FL5, FL6, and FL7;
(iii) Upstream Gauges--G1, G2, and G5;
(iv) Downstream Gauges--G3, G4, and G6;
(v) Pressure Gauges--P1, P2, P3, P4, P5, and P6;
(vi) Regulators--R1, R2, R3, R4, R5, R6, and R7;
(vii) Selector Valves--V1, V2, V3, V4, V6, V7, V8, V15, and V19;
(viii) Heated Selector Valves--V5, V13, V16, and V17;
(ix) Flow Control Valves--V9, V10, V11 and V12;
(x) Heated Flow Control Valves--V14 and V18;
(xi) Pump--Sample Transfer Pump;
(xii) Temperature Sensor--(T1);
(xiii) Dryer--D1 and D2; and
(xiv) Water traps--WT1 and WT2.
(A) Water removal from the sample shall be done by condensation.
(B) The sample gas temperature or dew point shall be monitored
either within the water trap or downstream of the water trap and shall
not exceed 45 deg. F (7 deg. C).
(C) Chemical dryers are not permitted.
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(2) The schematic of the gaseous sampling system shown in Figure E-
2 shall be used for testing category B engines. Various configurations
of Figure E-2 may produce equivalent results. The components are
designated as follows--
(i) Filters--F1, F2, F3, and F4;
(ii) Flowmeters--FL1, FL2, FL3, and FL4;
(iii) Upstream Gauges--G1, and G2;
(iv) Downstream Gauges--G3, and G4;
(v) Pressure Gauges--P1, P2, P3, and P4;
(vi) Regulators--R1, R2, R3, and R4;
(vii) Selector Valves--V1, V2, V3, V4, V6, and V7;
(viii) Heated Selector Valves--V5, V8, and V12;
(ix) Flow Control Valves--V9, V10, V11;
(x) Heated Flow Control Valves--V13;
(xi) Pump--Sample Transfer Pump;
(xii) Temperature Sensor--(T1); and
(xiii) Water traps--WT1 and WT2.
(A) Water removal from the sample shall be done by condensation.
(B) The sample gas temperature or dew point shall be monitored
either within the water trap or downstream of the water trap and shall
not exceed 45 deg.F (7 deg.C).
(C) Chemical dryers are not permitted.
(3) All components or parts of components that are in contact with
the sample gas or corrosive calibration gases shall be corrosion-
resistant material.
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(4) All analyzers shall obtain the sample to be analyzed from the
same sample probe.
(5) CO and CO2 measurements shall be made on a dry basis.
(6) Calibration or span gases for the NOX measurement system
shall pass through the NO2 to NO converter.
(7) A stainless steel sample probe shall be straight, closed-end,
multi-holed, and shall be placed inside the exhaust pipe.
(i) The probe length shall be at least 80 percent of the diameter
of the exhaust pipe.
(ii) The inside diameter of the sample probe shall not be greater
than the inside diameter of the sample line.
(iii) The heated sample line shall have a 0.197 inch (5 mm) minimum
and a 0.53 inch (13.5 mm) maximum inside diameter.
(iv) The wall thickness of the probe shall not be greater than
0.040 inch (1 mm).
(v) There shall be a minimum of 3 holes in 3 different radial
planes sized to sample approximately the same flow.
(8) The sample probe shall be located in the exhaust pipe at a
minimum distance of 1.6 feet (0.5 meters) or 3 times the diameter of
the exhaust pipe, whichever is the larger, from the exhaust manifold
outlet flange or the outlet of the turbocharger. The exhaust gas
temperature at the sample probe shall be a minimum of 158 deg. F
(70 deg. C).
(9) The maximum allowable leakage rate on the vacuum side of the
analyzer pump shall be 0.5 percent of the in-use flow rate for the
portion of the system being checked.
(10) General analyzer specifications.
(i) The total measurement error, including the cross sensitivity to
other gases, (paragraphs (b)(11)(ii), (b)(12)(iii), (b)(13)(iii), and
(b)(13)(iv) of this section), shall not exceed 5 percent of
the reading or 3.5 percent of full scale, whichever is
smaller. For concentrations of less than 100 ppm the measurement error
shall not exceed 4 ppm.
(ii) The repeatability, defined as 2.5 times the standard deviation
of 10 repetitive responses to a given calibration or span gas, must be
no greater than 1 percent of full scale concentration for
each range used above 155 parts per million (ppm) or parts per million
equivalent carbon (ppmC) or 2 percent of each range used
below 155 ppm (or ppmC).
(iii) The analyzer peak to peak response to zero and calibration or
span gases over any 10 second period shall not exceed 2 percent of full
scale on all ranges used.
(iv) The analyzer zero drift during a 1-hour period shall be less
than 2 percent of full scale on the lowest range used. The zero-
response is the mean response, including noise, to a zero gas during a
30-second time interval.
(v) The analyzer span drift during a 1-hour period shall be less
than 2 percent of full scale on the lowest range used. The analyzer
span is defined as the difference between the span response and the
zero response. The span response is the mean response, including noise,
to a span gas during a 30-second time interval.
(11) CO and CO2 analyzer specifications.
(i) Measurements shall be made with nondispersive infrared (NDIR)
analyzers.
(ii) For the CO analyzer, the water and CO2 interference shall
be less than 1 percent of full scale for ranges equal to or greater
than 300 ppm (3 ppm for ranges below 300 ppm) when a CO2 span gas
concentration of 80 percent to 100 percent of full scale of the maximum
operating range used during testing is bubbled through water at room
temperature.
(12) For NOX analysis using a chemiluminescence (CL) analyzer
the following parameters shall apply:
(i) From the sample point to the NO2 to NO converter, the
NOX sample shall be maintained between 131 deg. F (55 deg. C) and
392 deg. F (200 deg. C).
(ii) The NO2 to NO converter efficiency shall be at least 90
percent.
(iii) The quench interference from CO2 and water vapor must be
less than 3.0 percent.
(13) For NOX analysis using an NDIR analyzer system the
following parameters shall apply:
(i) The system shall include a NO2 to NO converter, a water
trap, and a NDIR analyzer.
(ii) From the sample point to the NO2 to NO converter, the
NOX sample shall be maintained between 131 deg. F (55 deg. C) and
392 deg. F (200 deg. C).
(iii) The minimum water rejection ratio (maximum water
interference) for the NOX NDIR analyzer shall be 5,000:1.
(iv) The minimum CO2 rejection ratio (maximum CO2
interference) for the NOX NDIR analyzer shall be 30,000:1.
(14) When CH4 is measured using a heated flame ionization
detector (HFID) the following shall apply:
(i) The analyzer shall be equipped with a constant temperature oven
that houses the detector and sample-handling components.
(ii) The detector, oven, and sample-handling components shall be
suitable for continuous operation at temperatures of 374 deg. F
(190 deg. C) 18 deg. F (10 deg. C).
(iii) The analyzer fuel shall contain 40 2 percent
hydrogen. The balance shall be helium. The mixture shall contain
1 part per million equivalent carbon (ppmC), and
400 ppm CO.
(iv) The burner air shall contain < 2 ppmC hydrocarbon.
(v) The percent of oxygen interference shall be less than 5
percent.
(15) An NDIR analyzer for measuring CH4 may be used in place
of the HFID specified in paragraph (b)(14) of this section and shall
conform to the requirements of paragraph (b)(10) of this section.
Methane measurements shall be made on a dry basis.
(16) Calibration gas values shall be traceable to the National
Institute for Standards and Testing (NIST), ``Standard Reference
Materials'' (SRM's). The analytical accuracy of the calibration gas
values shall be within 2.0 percent of NIST gas standards.
(17) Span gas values shall be traceable to NIST SRM's. The
analytical accuracy of the span gas values shall be within 2.0 percent
of NIST gas standards.
(18) Calibration or span gases for the CO and CO2 analyzers
shall have purified nitrogen as a diluent. Calibration or span gases
for the CH4 analyzer shall be CH4 with purified synthetic air
or purified nitrogen as diluent.
(19) Calibration or span gases for the NOX analyzer shall be
NO with a maximum NO2 concentration of 5 percent of the NO
content. Purified nitrogen shall be the diluent.
(20) Zero-grade gases for the CO, CO2, CH4 , and NOX
analyzers shall be either purified synthetic air or purified nitrogen.
(21) The allowable zero-grade gas (purified synthetic air or
purified nitrogen) impurity concentrations shall not exceed
1ppm C, 1 ppm CO, 400 ppm CO2, and
0.1 ppm NO.
(22) The calibration and span gases may also be obtained by means
of a gas divider. The accuracy of the mixing device must be such that
the concentration of the diluted calibration gases are within 2
percent.
(c) Particulate sampling system shall be used in determining the
particulate index. A schematic of a full flow (single dilution)
particulate sampling system for testing under this subpart is shown in
Figures E-3 and E-4.
(1) The dilution system shall meet the following parameters:
(i) Either a positive displacement pump (PDP) or a critical flow
venturi (CFV) shall be used as the pump/mass measurement device shown
in Figure E-3.
[[Page 55511]]
(ii) The total volume of the mixture of exhaust and dilution air
shall be measured.
(iii) All parts of the system from the exhaust pipe up to the
filter holder, which are in contact with raw and diluted exhaust gas,
shall be designed to minimize deposition or alteration of the
particulate.
(iv) All parts shall be made of electrically conductive materials
that do not react with exhaust gas components.
(v) All parts shall be electrically grounded to prevent
electrostatic effects.
(vi) Systems other than full flow systems may also be used provided
they yield equivalent results where:
(A) A seven sample pair (or larger) correlation study between the
system under consideration and a full flow dilution system shall be run
concurrently.
(B) Correlation testing is to be performed at the same laboratory,
test cell, and on the same engine.
(C) The equivalency criterion is defined as a 5
percent agreement of the sample pair averages.
(2) The mass of particulate in the exhaust shall be collected by
filtration. The exhaust temperature immediately before the primary
particulate filter shall not exceed 125 deg. F (52.0 deg. C).
(3) Exhaust system backpressure shall not be artificially lowered
by the PDP, CFV systems or dilution air inlet system. Static exhaust
backpressure measured with the PDP or CFV system operating shall remain
within 0.44 inches Hg (1.5 kPa) of the static pressure
measured without being connected to the PDP or CFV at identical engine
speed and load.
(4) The gas mixture temperature shall be measured at a point
immediately ahead of the pump or mass measurement device.
(i) Using PDP, the gas mixture temperature shall be maintained
within 10 deg. F (6.0 deg. C) of the average operating
temperature observed during the test, when no flow compensation is
used.
(ii) Flow compensation can be used provided that the temperature at
the inlet to the PDP does not exceed 122 deg. F (50 deg. C).
(iii) Using CFV, the gas mixture temperature shall be maintained
within 20 deg. F (11 deg. C) of the average operating
temperature observed during the test, when no flow compensation is
used.
(5) The heat exchanger shall be of sufficient capacity to maintain
the temperature within the limits required above and is optional if
electronic flow compensation is used.
(6) When the temperature at the inlet of either the PDP or CFV
exceeds the limits stated in either paragraphs (c)(4)(i) or (c)(4)(iii)
of this section, an electronic flow compensation system shall be
required for continuous measurement of the flow rate and control of the
proportional sampling in the particulate sampling system.
(7) The flow capacity of the system shall be large enough to
eliminate water condensation.
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(8) The flow capacity of the PDP or CFV system using single
dilution shall maintain the diluted exhaust at 125 deg.F (52.0 deg. C)
or less immediately before the primary particulate filter.
(9) The flow capacity of the PDP or CFV system using a double
dilution system shall be sufficient to maintain the diluted exhaust in
the dilution tunnel at 375 deg. F (191 deg. C) or less at the sampling
zone.
(10) The secondary dilution system shall provide sufficient
secondary dilution air to maintain the double-diluted exhaust stream at
125 deg. F (52.0 deg. C) or less immediately before the primary
particulate filter.
(11) The gas flow meters or the mass flow measurement
instrumentation shall have a maximum error of the measured value within
2 percent of reading.
(12) The dilution air shall have a temperature of 77 deg.
F9 deg. F (25 deg. C5 deg. C), and be--
(i) Filtered at the air inlet; or
(ii) Sampled to determine background particulate levels, which can
then be subtracted from the values measured in the exhaust stream.
(13) The dilution tunnel shall have the following specifications:
(i) Be small enough in diameter to cause turbulent flow (Reynolds
number greater than 4,000) and of sufficient length to cause complete
mixing of the exhaust and dilution air;
(ii) Be at least 3 inches (75 mm) in diameter; and
(iii) Be configured to direct the engine exhaust downstream at the
point where it is introduced into the dilution tunnel for thorough
mixing.
(14) The exhaust pipe length from the exit of the engine exhaust
manifold or turbocharger outlet to the dilution tunnel shall not exceed
a total length of 32 feet (10 m).
(i) When the exhaust pipe exceeds 12 feet (4 m), then all pipe in
excess of 12 feet (4 m) shall be insulated with a radial thickness of
at least 1.0 inch (25 mm) and the thermal conductivity of the
insulating material shall be no greater than 0.1 W/mK measured at
752 deg. F (400 deg. C).
(ii) To reduce the thermal inertia of the exhaust pipe, the
thickness to diameter ratio shall be 0.015 or less.
(iii) The use of flexible sections shall be limited to the length
to diameter ratio of 12 or less.
(15) The particulate sample probe shall--
(i) Be installed in the dilution tunnel facing upstream, on the
dilution tunnel centerline, and approximately 10 dilution tunnel
diameters downstream of the point where the engine's exhaust enters the
dilution tunnel; and
(ii) Have 0.5 inches (12 mm) minimum inside diameter.
(16) The inlet gas temperature to the particulate sample pump or
mass measurement device shall remain a constant temperature of
5 deg. F (3.0 deg. C) if flow compensation is not used.
(17) The secondary dilution portion of the double dilution system
shall have:
(i) A particulate transfer tube shall have a 0.5 inch (12 mm)
minimum inside diameter not to exceed 40 inches (1020 mm) in length
measured from the probe tip to the secondary dilution tunnel has:
(A) An inlet with the transfer tube facing upstream in the primary
dilution tunnel, centerline, and approximately 10 dilution tunnel
diameters downstream of the point where the engine's exhaust enters the
dilution tunnel.
(B) An outlet where the transfer tube exits on the centerline of
the secondary tunnel and points downstream.
(ii) A secondary tunnel that has a minimum diameter of 3.0 inches
(75 mm), and of sufficient length to provide a residence time of at
least 0.25 seconds for the double-diluted sample.
(iii) Secondary dilution air supplied at a temperature of 77 deg.F
9 deg. F(25 deg. C5 deg. C).
(iv) A primary filter holder located within 12.0 inches (300 mm) of
the exit of the secondary tunnel.
(18) The particulate sampling filters shall--
(i) Be fluorocarbon-coated glass fiber filters or fluorocarbon-
based (membrane) filters and have a 0.3 m di-octylphthalate
(DOP) collection efficiency of at least 95 percent at a gas face
velocity between 35 and 80 cm/s.;
(ii) Have a minimum diameter of 1.85 inches (47 mm), 1.46 inches
(37 mm) stain diameter;
(iii) Have a minimum filter loading ratio of 0.5mg/1075 mm \2\
stain area for the single filter method.
(iv) Have minimum filter loading such that the sum of all eight (8)
multiple filters is equal to the minimum loading value (mg) for a
single filter multiplied by the square root of eight (8).
(v) Be sampled at the same time by a pair of filters in series (one
primary and one backup filter) so that:
(A) The backup filter holder shall be located no more than 4 inches
(100 mm) downstream of the primary filter holder.
(B) The primary and backup filters shall not be in contact with
each other.
(C) The filters may be weighed separately or as a pair with the
filters placed stain side to stain side.
(D) The single filter method incorporates a bypass system for
passing the sample through the filters at the desired time.
(vi) Have a pressure drop increase between the beginning and end of
the test of no more than 7.4 in Hg (25kPa).
(vii) Filters of identical quality shall be used when performing
correlation tests specified in paragraph (c)(1)(vi) of this section.
(19) Weighing chamber specifications.
(i) The temperature of the chamber (room) in which the particulate
filters are conditioned and weighed shall be maintained to within 72
deg.F5 deg.F (22 deg.C3 deg.C) during all
filter conditioning and weighing.
(ii) The humidity of the chamber (room) in which the particulate
filters are conditioned and weighed shall be maintained to a dewpoint
of 49 deg.F5 deg.F (9.5 deg.C3 deg.C) and a
relative humidity of 45 percent 8 percent during all filter
conditioning and weighing.
(iii) The chamber (room) environment shall be free of any ambient
contaminants (such as dust) that would settle on the particulate
filters during their stabilization. This shall be determined as
follows:
(A) At least two unused reference filters or reference filter pairs
shall be weighed within four (4) hours of, but preferably at the same
time as the sample filter (pair) weighings.
(B) The reference filters are to be the same size and material as
the sample filters.
(C) If the average weight of reference filters (reference filter
pairs) changes between sample filter weighings by more than
5.0 percent (7.5 percent for the filter pair
respectively) of the recommended minimum filter loading in paragraphs
(c)(18)(iii) or (c)(18)(iv) of this section, then all sample filters
shall be discarded and the tests repeated.
(20) The analytical balance used to determine the weights of all
filters shall have a precision (standard deviation) of 20 g
and resolution of 10 g. For filters less than 70 mm diameter,
the precision and resolution shall be 2 g and 1 g,
respectively.
(21) All filters shall be neutralized to eliminate the effects of
static electricity prior to weighing.
Sec. 7.87 Test to determine the maximum fuel-air ratio.
(a) Test procedure.
(1) Couple the diesel engine to the dynamometer and connect the
sampling and measurement devices specified in Sec. 7.86.
(2) Prior to testing, zero and span the CO and NOX analyzers
to the lowest analyzer range that will be used during this test.
(3) While running the engine, the following shall apply:
[[Page 55515]]
(i) The parameter for the laboratory atmospheric factor, fa,
shall be: 0.98fa1.02;
(A) The equation is fa=(99/Ps) * ((Ta+273)/
298)0.7 for a naturally aspirated and mechanically supercharged
engines; or
(B) The equation is fa=(99/Ps)0.7* ((Ta+273)/
298) 1.5 for a turbocharged engine with or without cooling of the
intake air.
Where:
Ps=dry atmospheric pressure (kPa)
Ta=intake air temperature ( deg.C)
(ii) The air inlet restriction shall be set within 10
percent of the recommended maximum air inlet restriction as specified
by the engine manufacturer at the engine operating condition giving
maximum air flow to determine the concentration of CO as specified in
paragraph (a)(6) of this section.
(iii) The exhaust backpressure restriction shall be set within
10 percent of the maximum exhaust backpressure as specified
by the engine manufacturer at the engine operating condition giving
maximum rated horsepower to determine the concentrations of CO and
NOX as specified in paragraph (a)(6)of this section.
(iv) The air inlet restriction shall be set within 10
percent of a recommended clean air filter at the engine operating
condition giving maximum air flow as specified by the engine
manufacturer to determine the concentration of NOX as specified in
paragraph (a)(6) of this section.
(4) The engine shall be at a steady-state condition when the
exhaust gas samples are collected and other test data is measured.
(5) In a category A engine, 1.00.1 percent CH4
shall be injected into the engine's intake air.
(6) Operate the engine at several speed/torque conditions to
determine the concentrations of CO and NOX, dry basis, in the raw
exhaust.
(b) Acceptable performance. The CO and NOX concentrations in
the raw exhaust shall not exceed the limits specified in Sec. 7.84(b)
throughout the specified operational range of the engine.
Sec. 7.88 Test to determine the gaseous ventilation rate.
The test shall be performed in the order listed in Table E-2. The
test for determination of the particulate index described in Sec. 7.89
may be done simultaneously with this test.
(a) Test procedure.
(1) Couple the diesel engine to the dynamometer and attach the
sampling and measurement devices specified in Sec. 7.86.
(2) A minimum time of 10 minutes is required for each test mode.
(3) CO, CO2, NOX, and CH4 analyzers shall be zeroed
and spanned at the analyzer range to be used prior to testing.
(4) Run the engine.
(i) The parameter for fa shall be calculated in accordance
with Sec. 7.87(a)(3).
(ii) The air inlet and exhaust backpressure restrictions on the
engine shall be set as specified in Secs. 7.87(a)(3) (iii) and (iv).
(5) The engine shall be at a steady-state condition before starting
the test modes.
(i) The output from the gas analyzers shall be measured and
recorded with exhaust gas flowing through the analyzers a minimum of
the last three (3) minutes of each mode.
(ii) To evaluate the gaseous emissions, the last 60 seconds of each
mode shall be averaged.
(iii) A 1.00.1 percent CH4, by volume, shall be
injected into the engine's intake air for category A engines.
(iv) The engine speed and torque shall be measured and recorded at
each test mode.
(v) The data required for use in the gaseous ventilation
calculations specified in paragraph (a)(9) of this section shall be
measured and recorded at each test mode.
(6) Operate the engine at each rated speed and horsepower rating
requested by the applicant according to Table E-2 in order to measure
the raw exhaust gas concentration, dry basis, of CO, CO2, NO, and
NO2, and CH4- exhaust (category A engines only).
(i) Test speeds shall be maintained within 1 percent of
rated speed or 3 RPM, which ever is greater, except for low
idle which shall be within the tolerances established by the
manufacturer.
(ii) The specified torque shall be held so that the average over
the period during which the measurements are taken is within
2 percent of the maximum torque at the test speed.
(7) The concentration of CH4 in the intake air shall be
measured for category A engines.
Table E-2.--Gaseous Test Modes
Speed Rated speed Intermediate speed Low-
--------------------------------------------------------------------------------------------------------- idle
speed
% Torque 100 75 50 10 100 75 50 -------
0
----------------------------------------------------------------------------------------------------------------
(8) After completion of the test modes, the following shall be
done:
(i) Zero and span the analyzers at the ranges used during the test.
(ii) The gaseous emission test shall be acceptable if the
difference in the zero and span results taken before the test and after
the test are less than 2 percent.
(9) The gaseous ventilation rate for each exhaust gas contaminant
shall be calculated as follows--
(i) The following abbreviations shall apply to both category A and
category B engine calculations as appropriate:
cfm--Cubic feet per min (ft3/min)
Exh--Exhaust
A--Air (lbs/hr)
H--Grains of water per lb. of dry intake air
J--Conversion factor
m--Mass flow rate (mass/hr)
TI--Intake air temperature ( deg. F)
PCAir--Percent Air
PCCH4--Percent CH4 (intake air)
UCH4--Unburned CH4
PCECH4--Percent Exhaust CH4
(ii) Exhaust gas flow calculation for category B engines shall be
(m Exh)=(A)+(m fuel).
(iii) Fuel/air ratio for category B engines shall be (f/a)=(m fuel)
/ (A).
(iv) Methane flow through category A engines shall be determined by
the following:
PCAir=100-PCCH4
Y=(PCAir)(0.289)+(PCCH4)(0.16)
Z=(0.16)(PCCH4)Y
mCH4=(A)(Z)(1-Z)
[[Page 55516]]
(v) Exhaust gas flow calculation for category A engines shall be (m
Exh)=(A)+(m fuel)+(m CH4)
(vi) Unburned CH4 (lbs/hr) calculation for category A engines
shall be mUCH4=(m Exh)(0.00552)(PCECH4)
(vii) Fuel/air ratio for category A engines shall be (f/a)=((m
fuel)+(m CH4)-(m UCH4))(A)
(viii) Conversion from dry to wet basis for both category A and
category B engines shall be:
(NO wet basis)=(NO dry basis)(J)
(NO2 wet basis)=(NO2 dry basis)(J)
(CO2 wet basis)=(CO2 dry basis)(J)
(CO wet basis)=(CO dry basis)(10-4)(J)
Where:
J=(f/a)(-1.87)+(1-(0.00022)(H))
(ix) NO and NO2 correction for humidity and temperature for
category A and category B engines shall be:
(NO corr)=(NO wet basis)(E)
(NO2 corr)=(NO2 wet basis)(E)
Where:
E=1.0+(R)(H-75)+(G)(TI-77)
R=(f/a)(0.044)-(0.0038)
G=(f/a)(-0.116)+(0.0053)
(x) The calculations to determine the m of each exhaust gas
contaminant in grams per hour at each test point shall be as follows
for category A and category B engines:
(m NO)=(NO corr)(0.000470)(m Exh)
(m NO2)=(NO2 corr)(0.000720)(m Exh)
(m CO2)=(CO2 wet basis)(6.89)(m Exh)
(m CO)=(CO wet basis)(4.38)(m Exh)
(xi) The calculations to determine the ventilation rate for each
exhaust gas contaminant at each test point shall be as follows for
category A and category B engines:
(cfm NO)=(m NO)(K)
(cfm NO2)=(m NO2)(K)
(cfm CO2)=(m CO2)(K)
(cfm CO)=(m CO)(K)
Where:
K=13,913.4 (pollutant grams/mole) (pollutant dilution value specified
in Sec. 7.84(c)).
(b) The gaseous ventilation rate for each requested rated speed and
horsepower shall be the highest ventilation rate calculated in
paragraph (a)(9)(xi) of this section.
(1) Ventilation rates less than 20,000 cfm shall be rounded up to
the next 500 cfm.
Example: 10,432 cfm shall be listed 10,500 cfm.
(2) Ventilation rates greater than 20,000 cfm shall be rounded up
to the next 1,000 cfm.
Example: 26,382 cfm shall be listed 27,000 cfm.
Sec. 7.89 Test to determine the particulate index.
The test shall be performed in the order listed in Table E-3.
(a) Test procedure.
(1) Couple the diesel engine to the dynamometer and connect the
sampling and measurement devices specified in Sec. 7.86.
(2) A minimum time of 10 minutes is required for each measuring
point.
(3) Prior to testing, condition and weigh the particulate filters
as follows:
(i) At least 1 hour before the test, each filter (pair) shall be
placed in a closed, but unsealed, petri dish and placed in a weighing
chamber (room) for stabilization.
(ii) At the end of the stabilization period, each filter (pair)
shall be weighed. The reading is the tare weight.
(iii) The filter (pair) shall then be stored in a closed petri dish
or a filter holder, both of which shall remain in the weighing chamber
(room) until needed for testing.
(iv) The filter (pair) must be re-weighed if not used within 8
hours of its removal from the weighing chamber (room).
(4) Run the engine.
(i) The parameter for fa shall be calculated in accordance
with Sec. 7.87(a)(3).
(ii) The air inlet and exhaust backpressure restrictions on the
engine shall be set as specified in Secs. 7.87(a)(3) (iii) and (iv).
(iii) The dilution air shall be set to obtain a maximum filter face
temperature of 125 deg. F (52 deg. C) or less at each test mode.
(iv) The total dilution ratio shall not be less than 4.
(5) The engine shall be at a steady state condition before starting
the test modes.
(i) The engine speed and torque shall be measured and recorded at
each test mode.
(ii) The data required for use in the particulate index calculation
specified in paragraph (a)(9) of this section shall be measured and
recorded at each test mode.
(6) A 1.00.1 percent CH4, by volume shall be
injected into the engine's intake air for category A engines.
(7) Operate the engine at each rated speed and horsepower rating
requested by the applicant according to Table E-3 to collect
particulate on the primary filter.
(i) One pair of single filters shall be collected or eight multiple
filter pairs shall be collected.
(ii) Particulate sampling shall be started after the engine has
reached a steady-state condition.
(iii) The sampling time required per mode shall be either a minimum
of 20 seconds for the single filter method or a minimum of 60 seconds
for the multiple filter method.
(iv) The minimum particulate loading specified in Secs. 7.86(c)(18)
(iii) or (iv) shall be done.
Table E-3.--Particulate Test Modes
----------------------------------------------------------------------------------------------------------------
Speed Rated speed Intermediate speed Low-
--------------------------------------------------------------------------------------------------------- idle
speed
% Torque 100 75 50 10 100 75 50 -------
0
----------------------------------------------------------------------------------------------------------------
Weighting factor................................ 0.15 0.15 0.15 0.1 0.1 0.1 0.1 0.15
----------------------------------------------------------------------------------------------------------------
(v) Test speeds shall be maintained within percent of
rated speed or 3 RPM, which ever is greater, except for low
idle which shall be within the tolerances set by the manufacturer.
(vi) The specified torque shall be held so that the average over
the period during which the measurements are being taken is within
2 percent of the maximum torque at the test speed.
(vii) The modal weighting factors (WF) given in Table E-3 shall be
applied to the multiple filter method during the calculations as shown
in paragraph (a)(9)(iii)(B) of this section.
(viii) For the single filter method, the modal WF shall be taken
into account during sampling by taking a sample proportional to the
exhaust mass flow for each mode of the cycle.
(8) After completion of the test, condition and weigh the
particulate filters in the weighing chamber (room) as follows:
(i) Condition the filters for at least 1 hour, but not more than 80
hours.
[[Page 55517]]
(ii) At the end of the stabilization period, weigh each filter. The
reading is the gross weight.
(iii) The particulate mass of each filter is its gross weight minus
its tare weight.
(iv) The particulate mass (PF for the single filter method;
PF,i for the multiple filter method) is the sum of the
particulate masses collected on the primary and back-up filters.
(v) The test is void and must be rerun if the sample on the filter
contacts the petri dish or any other surface.
(9) The particulate index for the mass particulate shall be
calculated from the equations listed below--
(i) The following abbreviations shall be:
cfm--Cubic feet per min (ft\3\ min)
PT--Particulate (gr/hr)
m mix--Diluted exhaust gas mass flow rate on wet basis (kg/hr)
m sample--Mass of the diluted exhaust sample passed through the
particulate sampling filters (kg)
PF--Particulate sample mass collected on a filter (mg) at each
test mode as determined in Table E-3.
Kp--Humidity correction factor for particulate
WF--Weighting factor
i-Subscript denoting an individual mode, i=1, . . . n
PI--Particulate Index (cfm)
(ii) When calculating ambient humidity correction for the
particulate concentration (PF part), the equation shall be:
Pfcorr=(Pf)(Kp)
Kp=1/(1+0.0133 * (H-10.71))
Where:
Ha=humidity of the intake air, g water per kg dry air
H