[Federal Register Volume 73, Number 76 (Friday, April 18, 2008)]
[Rules and Regulations]
[Pages 21182-21209]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 08-1152]



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Part III





Department of Labor





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Mine Safety and Health Administration



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30 CFR Part 75



Sealing of Abandoned Areas; Final Rule

  Federal Register / Vol. 73, No. 76 / Friday, April 18, 2008 / Rules 
and Regulations  

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DEPARTMENT OF LABOR

Mine Safety and Health Administration

30 CFR Part 75

RIN 1219-AB52


Sealing of Abandoned Areas

AGENCY: Mine Safety and Health Administration (MSHA), Labor.

ACTION: Final rule.

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SUMMARY: This final rule revises MSHA's Emergency Temporary Standard 
(ETS) and addresses sealing abandoned areas in underground coal mines. 
The final rule includes requirements for seal strength, design, 
construction, maintenance and repair of seals and monitoring and 
control of atmospheres behind seals in order to reduce the risk of seal 
failure and the risk of explosions in abandoned areas of underground 
coal mines. It also addresses the level of overpressure for new seals.

EFFECTIVE DATE: This final rule is effective April 18, 2008.

FOR FURTHER INFORMATION CONTACT: Patricia W. Silvey, Director, Office 
of Standards, Regulations, and Variances, MSHA, 1100 Wilson Blvd., Room 
2350, Arlington, Virginia 22209-3939, [email protected] (e-mail), 
(202) 693-9440 (voice), or (202) 693-9441 (telefax).

SUPPLEMENTARY INFORMATION:
    The outline of the final rule is as follows:

I. Background
II. Discussion of the Final Rule
III. Section-by-Section Analysis
IV. Executive Order 12866
    A. Mine Sector Affected
    B. Benefits
    C. Compliance Costs
V. Feasibility
    A. Technological Feasibility
    B. Economic Feasibility
VI. Regulatory Flexibility Act and Small Business Regulatory 
Enforcement Fairness Act
    A. Definition of Small Mine
    B. Factual Basis for Certification
VII. Paperwork Reduction Act of 1995
    A. Summary
    B. Details
VIII. Other Regulatory Considerations
    A. The Unfunded Mandates Reform Act of 1995
    B. The Treasury and General Government Appropriations Act of 
1999: Assessment of Federal Regulations and Policies on Families
    C. Executive Order 12630: Government Actions and Interference 
With Constitutionally Protected Property Rights
    D. Executive Order 12988: Civil Justice Reform
    E. Executive Order 13045: Protection of Children From 
Environmental Health Risks and Safety Risks
    F. Executive Order 13132: Federalism
    G. Executive Order 13175: Consultation and Coordination With 
Indian Tribal Governments
    H. Executive Order 13211: Actions Concerning Regulations That 
Significantly Affect Energy Supply, Distribution, or Use
    I. Executive Order 13272: Proper Consideration of Small Entities 
in Agency Rulemaking
IX. References

I. Background

    In the Federal Coal Mine Health and Safety Act of 1969 (Coal Act), 
the predecessor to the existing Mine Act, Congress first recognized 
that mine operators must isolate abandoned areas of underground coal 
mines from active workings for the protection of miners' safety:

    In the case of mines opened on or after the operative date of 
this title, or in the case of areas developed on or after such date 
in mines opened prior to such date, the mining system shall be 
designed, in accordance with a plan and revisions thereof approved 
by the Secretary and adopted by the operator, so that, as each set 
of cross entries, room entries, or panel entries of the mine are 
abandoned, they can be isolated from active workings of the mine 
with explosion-proof bulkheads.

Pub. Law 91-173 (Dec. 1969) Section 303(2)(3).
    In the conference report filed in the House, the statement of the 
managers on the part of the House stated, regarding the requirement 
that an abandoned area of a mine either be ventilated or sealed, that:

[t]he determination of which method [(ventilated or sealed)] is 
appropriate and the safest at any mine is up to the Secretary or 
[her] inspector to make, after taking into consideration the 
conditions of the mine, particularly its history of methane and 
other explosive gases. The objective is that [s]he require the means 
that will provide the greatest degree of safety in each case. * * * 
When sealing is required, such sealing shall be made in an approved 
manner so as to isolate with explosion-proof bulkheads such areas 
from the active working of the mine.
    Under the conference substitute, paragraph (3) of section 303(z) 
provides that, in the case of mines opened on or after the operative 
date of this title, or in the case of areas developed on or after 
such date in mines opened prior to such date, the mining system 
shall be designed, in accordance with a plan and revisions thereof 
approved by the Secretary and adopted by the operator, so that, as 
each set of cross entries, room entries, or panel entries of the 
mine are abandoned, they can be isolated from active workings of the 
mine with explosion-proof bulkheads approved by the Secretary or his 
inspector.
    The managers expect the Secretary to take the lead in improving 
technology in this area of controlling methane accumulations in gob 
areas and to improve upon this important section 303(z).

Conf. Rep. No. 91-761, 91st Cong. 1st Sess., 82 (Dec. 16, 1969) 
(statement of the managers on part of the House) (emphasis added).
    The Mine Act interim mandatory standards required seals to be 
``made in an approved manner so as to isolate with explosion-proof 
bulkheads such areas from the active workings of the mine.'' 30 
U.S.C.863(z)(2).
    On May 15, 1992, as part of a comprehensive revision of its 
standards for ventilation of underground coal mines, MSHA published 
standards for construction of seals in Sec.  75.335 of the ventilation 
standards (57 FR 20868). The standard required seals to be constructed 
of solid concrete blocks at least six inches by eight inches by sixteen 
inches, but allowed seals to be constructed using alternative methods 
and materials, provided, among other things, that the seal was capable 
of withstanding a horizontal static pressure of 20 psi. MSHA based this 
threshold on a U.S. Bureau of Mines 1971 report entitled ``Explosion--
Proof Bulkheads--Present Practices.''
    A number of manufacturers developed materials, such as cementitious 
foams and glass-fiber material, which were tested and subsequently 
deemed suitable for use in alternative seals and marketed under various 
trade names. MSHA required the manufacturers to have full-scale seals 
be subjected to explosion testing at the National Institute for 
Occupational Safety and Health (NIOSH) Lake Lynn Experimental Mine 
(Lake Lynn). MSHA then intended for mine operators to construct seals 
as constructed and tested at Lake Lynn.
    On January 2, 2006, an explosion at the Sago Mine in Upshur County, 
West Virginia caused the death of twelve miners. Later that year, on 
May 20, 2006, an explosion at the Darby Mine No. 1 in Harlan County, 
Kentucky, caused the death of five miners. Common to both of these 
accidents was the failure of the seals in the mine. The failed seals in 
both mines were constructed with the same approved alternative material 
for a 20-psi seal. None of the failed seals were constructed in the 
same manner as they were constructed at Lake Lynn. Therefore, MSHA 
issued a moratorium on alternative methods and materials for 
construction of new seals (Program Information Bulletin (PIB) No. P06-
11, June 1, 2006, reissued on June 12, 2006 as PIB No. P06-12, reissued 
on June 21, 2006 as PIB No. PO6-14).

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    Following these underground coal mine disasters in 2006, Congress 
passed and the President signed the MINER Act. Section 10 of the MINER 
Act requires the Secretary of Labor to finalize mandatory health and 
safety standards relating to the sealing of abandoned areas in 
underground coal mines, and to increase the 20 psi standard.
    MSHA increased the strength of alternative seals to 50 psi and 
addressed a number of other issues related to the construction and the 
effectiveness of existing alternative and solid concrete block seals in 
Program Information Bulletin No. P06-16, ``Use of Alternative Seal 
Methods and Materials Pursuant to 30 CFR 75.335(a)(2),'' issued on July 
19, 2006 (July 2006 PIB).
    On February 8, 2007, NIOSH issued a draft report, ``Explosion 
Pressure Design Criteria for New Seals in U.S. Coal Mines'' (2007 NIOSH 
Draft Report). The draft report states that ``mine seals and their 
related systems such as the monitoring, inertization and ventilation 
systems require the highest level of engineering and quality assurance. 
Successful implementation of the seal design criteria and 
recommendations in this report should reduce the risk of seal failure 
due to explosions in abandoned areas of underground coal mines.'' (2007 
NIOSH Draft Report at 40). In the executive summary of the draft 
report, NIOSH made recommendations for formulating seal design 
criteria.
    On May 22, 2007, MSHA published an Emergency Temporary Standard; 
notice of public hearings; and notice of close of comment period (72 FR 
28796). The comment period, scheduled to close on July 6, 2007, was 
extended to August 17, 2007 (72 FR 34609) and four public hearings were 
held. The hearings were held on July 10, 2007, in Morgantown, West 
Virginia; on July 12, 2007, in Lexington, Kentucky; on July 17, 2007, 
in Denver, Colorado; and on July 19, 2007, in Birmingham, Alabama.
    On August 14, 2007, MSHA extended the comment period to September 
17, 2007, (72 FR 45358) to allow commenters additional time to review 
recently posted documents on MSHA's Web site and a recently published 
report from NIOSH entitled ``Explosion Pressure Design Criteria for New 
Seals in U.S. Coal Mines,'' NIOSH Publication No. 2007-144, July 2007, 
IC-9500 (2007 NIOSH Final Report). With one exception, the final 
version of this report was little changed from the draft version of 
this report that was referenced in the ETS. The final report includes a 
new section 3.3, Homogeneous Methane-Air Mixtures in Sealed-Area 
Atmospheres. This new section discusses methane layering in sealed 
areas and asserts that gaseous diffusion will result in a relatively 
homogeneous mixture within a matter of days after sealing. Other minor 
changes are related to rounding to metric units (sample pipes should 
extend 16 feet (5 meters) into the sealed area) and the inclusion of 
recent NIOSH research on methane flammability that lists the 
flammability range of methane-air mixtures at sea level as 5.0 percent 
to 16.0 percent methane.
    On December 7, 2007, MSHA posted on the Agency's Web site the U.S. 
Army Corps of Engineer's Draft Report ``CFD [Computational Fluid 
Dynamics] Study and Structural Analysis of the Sago Mine Accident'' 
(USACE's Draft Report). The Agency placed the Report in the rulemaking 
record for the ETS on Sealing of Abandoned Areas. The Report summarizes 
the preliminary results of a study performed by the USACE under 
contract (MSHA NO IA-AR 600012) for MSHA's Technical Support 
Directorate (Technical Support). The USACE conducted research from 
August 2006 to April 2007. The USACE provided a draft of the Report of 
their findings to Technical Support in May of 2007. The Report details 
the USACE's efforts to mathematically model the methane explosion at 
the Sago Mine and potentially establish the seal overpressures.
    On December 19, 2007, MSHA published a notice (72 FR 71791) to 
reopen the comment period; announce availability of the USACE's Draft 
Report; schedule a public hearing; and announce the close of the 
comment period. A public hearing was held in Arlington, Virginia on 
January 15, 2008 and the comment period closed on January 18, 2008.
    In developing this final rule, MSHA considered the investigation 
reports of the Sago and Darby mine explosions, implementation and 
enforcement experience under the ETS, MSHA's in-mine seal evaluations 
and review of technical literature, the 2007 NIOSH Draft and Final 
Reports on explosion testing and modeling, the USACE's Draft Report, 
accident reports, research studies, public comments, hearing 
transcripts and supporting documentation from all segments of the 
mining community.

II. Discussion of the Final Rule

    This final rule assures that miners can rely on seals to protect 
them from the hazardous and sometimes explosive environments within 
sealed areas. This final rule includes requirements for seal strengths; 
design applications and installation; sampling and monitoring of sealed 
atmospheres; construction and repair of seals, training for persons 
conducting sampling and persons constructing or repairing seals, and 
recordkeeping to protect miners from hazards of sealed areas.
    Underground coal mines are dynamic work environments in which the 
working conditions can change rapidly. Caved, mined-out areas may 
contain coal dust and accumulated gas which can be ignited by rock 
falls, lightning, and in some instances, fires started by spontaneous 
combustion. Seals are used to isolate this environment from the active 
workings of the mine. Seals are also installed to withstand 
overpressures resulting from explosions in abandoned areas and to 
prevent the potentially explosive methane/air mixtures from migrating 
to the working areas. Overpressure is the pressure above the background 
atmospheric pressure. For example, air pressure in a car tire is 
measured with a pressure gauge as 30 psi, which is an overpressure. The 
absolute pressure of the air inside the tire is 44.7 psi which is 14.7 
psi or one atmosphere higher. Explosion pressures are normally 
expressed as an overpressure beyond standard atmospheric pressure.
    A methane/air mixture becomes explosive when 5 percent to 15 
percent methane is present with at least a 12 percent oxygen 
concentration. If an ignition source is available, then an explosion 
can occur and create overpressures. The homogeneity of the methane/air 
mixture contributes to the magnitude of the explosion. The homogeneity 
of the methane/air mixture can vary depending on the elevation and the 
methane liberation of the sealed area and outside factors such as the 
temperature and barometric pressure. The speed of an explosion and the 
physical characteristics of a sealed area can increase the force of the 
explosion such that detonations and significant pressure piling may be 
possible.
    Pressure piling is the development of pressure in excess of normal 
atmospheric pressures as a result of the velocity-related compression 
of the gases in front of the flame. Pressure piling results from the 
rapid acceleration of the front of the flame. This acceleration process 
may be increased by cross-sectional restrictions, obstructions and 
other irregularities in the path of the flame. If the air flow ahead of 
the front of the flame is sufficiently turbulent, the flame speed may 
increase and transition from deflagration to detonation. A detonation 
occurs when the flame of an explosion propagates through the unburned 
fuel at

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a velocity exceeding the speed of sound. A deflagration occurs when the 
flame of an explosion propagates through unburned fuel at a velocity 
below the speed of sound.
    This final rule addresses seal strength design, construction, 
maintenance and repair of seals and monitoring and control of 
atmospheres behind seals in order to reduce the risk of seal failure 
and the risk of explosions in abandoned areas of underground coal 
mines. It also addresses the level of overpressure for new seals. This 
final rule will protect miners from hazards of sealed areas.

III. Section-by-Section Analysis

A. Section 75.335 Seal Strengths, Design Applications, and Installation

    The final rule addresses the requirements for seal strengths, 
design applications, and seal installation.
1. Section 75.335(a) Seal Strengths
    Final Sec.  75.335(a) requires that seals constructed in 
underground coal mines after October 20, 2008 be designed, constructed 
and maintained in accordance with the provisions of this final rule.
    Final Sec.  75.335(a)(1)(i), like the ETS, requires that seals 
withstand at least 50-psi overpressure when the atmosphere in the 
sealed area is monitored and maintained inert. Final Sec.  
75.335(a)(1)(i) adds new requirements that these seals be designed 
using a pressure-time curve with an instantaneous overpressure of at 
least 50 psi, and that the minimum overpressure must be maintained for 
at least four seconds and then released instantaneously.
    Final Sec.  75.335(a)(1)(ii) addresses new requirements that seals 
constructed to separate the active longwall panel from the longwall 
panel previously mined be designed using a pressure-time curve with a 
rate of pressure rise of at least 50 psi in 0.1 second, and that a 
minimum overpressure of at least 50 psi be maintained.
    Final Sec.  75.335(a)(2)(i) revises the ETS and requires that seals 
withstand overpressures of at least 120 psi if the atmosphere in the 
sealed area is not monitored, is not maintained inert, and the 
conditions in final Sec.  75.335(a)(3)(i) through (iii) of this section 
are not present. Final Sec.  75.335(a)(2)(i) also adds new requirements 
that these seals be designed using a pressure-time curve with an 
instantaneous overpressure of at least 120 psi, and that a minimum 
overpressure of 120 psi be maintained for at least four seconds and 
then released instantaneously.
    Final Sec.  75.335(a)(2)(ii) adds new requirements that seals 
constructed to separate the active longwall panel from the longwall 
panel previously mined be designed using a pressure-time curve with a 
rate of pressure rise of 120 psi in 0.25 second, and that a minimum 
overpressure of 120 psi be maintained.
    Final Sec.  75.335(a)(3) is essentially unchanged from the ETS. It 
requires seals to withstand overpressures greater than 120 psi if the 
atmosphere in the sealed area is not monitored and is not maintained 
inert, and either (i) the atmosphere in the sealed area is likely to 
contain homogeneous mixtures of methane between 4.5 percent and 17.0 
percent and oxygen exceeding 17.0 percent throughout the entire area; 
or (ii) pressure piling could result in overpressures greater than 120 
psi in the area to be sealed; or (iii) other conditions are 
encountered, such as the likelihood of a detonation in the area to be 
sealed.
    Final Sec.  75.335(a)(3)(iv) retains the ETS requirement that when 
homogenous explosive atmospheres, pressure piling or the likelihood of 
a detonation exists, the mine operator must revise the ventilation plan 
to address the potential hazards. In addition, the operator must 
conduct an analysis of the mining conditions and revise the plan to 
include seal strengths sufficient to address these conditions.
    MSHA received many comments in response to its request on the 
appropriateness of the three-tiered approach to seal strength in the 
ETS. One commenter stated that the strength requirements in the first 
and second tier are arbitrary. Other commenters objected to the fixed 
seal strengths and requested that either a case-by-case determination 
or a risk analysis be made to determine which seal strength is needed. 
One commenter suggested that a two-tiered approach is adequate and that 
a third tier is not needed. A commenter stated that the 120-psi value 
proposed in the ETS is sufficient for design purposes and that the 120-
psi load prescribed by the ETS is the highest design criterion for 
seals among all the coal producing countries. Another commenter stated 
that an explosion with a force greater than 120 psi could not occur in 
an underground coal mine. Other commenters, however, stated that 
greater than 120-psi explosion pressures can occur in sealed areas. 
Some commenters suggested that a 640-psi seal, as recommended by NIOSH, 
should be included in the standard. One commenter on the USACE's Draft 
Report stated that MSHA should consider a provision in the final rule 
that would assure that seals are explosion-proof.
    The Agency believes that a risk based analysis to determine seal 
strengths on a case-by-case basis rather than the tiered approach is 
not appropriate for several reasons. In the ETS, the Agency requested 
comments on alternatives to the seal strength requirements in the ETS, 
including supporting data, feasibility, and costs. MSHA did not receive 
any specific information, relative to alternatives requested, that 
would support a risk-based analysis on a case-by-case basis in this 
final rule. The rulemaking record contains little information 
supporting a case for risk analysis or costs and feasibility of such an 
approach. Commenters did not address how risk analysis on a case-by-
case basis would impact the final rule and miner safety. Since the 
rulemaking record does not support this alternative approach to 
determine seal strengths, MSHA has not included it in this final rule.
    The strength requirements for final Sec.  75.335(a) are based on 
MSHA's investigation of the explosion at the Sago mine and the 2007 
NIOSH Final Report. NIOSH discovered through research testing and 
modeling that a 50-psi peak overpressure could occur in a limited-
volume, unconfined situation. Small, unconfined pockets of gases in an 
explosive concentration could always exist in a sealed area. If any of 
these pockets were ignited, a 50-psi pressure pulse could be generated.
    In addition, NIOSH stated that a 120-psi peak pressure could occur 
in a limited, confined-volume situation. According to NIOSH, in such a 
situation, even if the overall concentration of explosive gases in the 
gob is well above the explosive concentration, explosive concentrations 
could be present in some areas. NIOSH further stated that if an 
explosive mix of methane and oxygen is ignited in this situation, an 
explosion could generate a peak explosion pressure of 120-psi. Based on 
the 2007 NIOSH Final Report and the Agency's data and experience, this 
final rule retains the second tier of the ETS.
    Unlike NIOSH's design curves for 50-psi and 120-psi overpressures, 
NIOSH did not recommend a static approximation to the 640-psi pressure-
time curve because ``Additional studies are required * * *.'' (2007 
NIOSH Final Report at pg. 61). Although the NIOSH 640-psi pressure-time 
curve could be used to design seals, in this case a dynamic analysis 
would have to be conducted by the professional engineer. MSHA 
considered NIOSH's 640-psi seal design. However, a prescriptive 
specific dynamic load factor based on the 640-psi design was not 
determined and

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requires further studies as stated in the 2007 NIOSH Final Report. As 
stated in the ETS, ``Although the recommended maximum seal strength in 
the 2007 NIOSH Draft Report is 640 psi, MSHA has no empirical or other 
data at this time, demonstrating that mine conditions exist that will 
necessitate seals stronger than 120 psi.'' One commenter on the USACE's 
draft report questioned this statement. MSHA stated in a Memorandum 
from its Office of Technical Support that ``these comparisons [between 
the USACE Report and known conditions after the Sago Mine explosion] 
again brought the practical applicability of results of the study into 
question.'' The Memorandum further states that: ``Technical Support 
decided not to publish the study because the critical information 
necessary to develop an accurate simulation was not available, and 
therefore, any results could not be relied upon for decision-making. 
Much of the data provided to the USACE for the three simulations 
described in the draft report was speculative * * *''
    Based on the Agency's available information and data, MSHA could 
not specifically recommend a 640-psi strength requirement. The final 
rule retains the third tier of the ETS and requires a seal stronger 
than 120 psi if certain conditions are encountered. Under the final 
rule, mine operators must perform a risk analysis and evaluate the 
atmosphere of the area to be sealed and determine when higher pressure 
seals should be used and at what strength. The seal design must be 
approved at the appropriate strength for the specific conditions to be 
encountered.
    Most commenters expressed concern that under the ETS, it is 
virtually impossible to determine when the conditions requiring a seal 
greater than 120 psi are present. MSHA has structured the final rule to 
accommodate pressures greater than 120 psi in recognition of the fact 
that explosion pressures may exceed this limit under certain 
conditions. These conditions would be a concern only in sealed areas 
that are not monitored and not maintained inert. The final rule 
requires seal strengths greater than 120 psi if seals are constructed 
around areas that are not monitored and are not inert, and one of the 
following three conditions occurs: (1) A homogeneous explosive 
atmosphere exists, (2) pressure piling could result in pressures 
exceeding 120 psi, or (3) detonation is likely.
    MSHA expects that mine operators will sample an appropriate number 
of locations within the sealed area during the period when seals are 
reaching their design strength to address whether a homogeneous 
explosive atmosphere exists. These samples could be taken at various 
locations, including through seals constructed around the sealed area 
and possibly through boreholes or shafts within the sealed area. When 
these seals reach design strength of 120 psi, sampling is no longer 
required. If the methane concentration stabilizes between 4.5 percent 
and 17 percent and the oxygen concentration remains above 17 percent in 
all samples, then the atmosphere is considered homogeneous throughout 
the sealed area, and seal strengths must be designed to an adequate 
level above 120 psi, as determined by the professional engineer, which 
will provide adequate protection for miners underground. MSHA realizes 
that the seals surrounding the sealed area must be in place prior to 
sampling.
    MSHA expects that mine operators will evaluate the physical 
characteristics of the underground workings near all seals surrounding 
the sealed area to address whether pressure piling can occur to a 
degree that causes explosion overpressures to exceed 120 psi. 
Overpressures that occurred during the 2006 explosion at the Sago Mine 
increased in magnitude due to a severe change in the physical 
characteristics of the underground workings near the seals. The seals 
at the Sago Mine were constructed to a height of approximately 7 feet. 
The workings in the sealed area had been previously second mined to a 
height of nearly 20 feet in some locations near the seals. As the 
explosion propagated toward the seals, pressure piling occurred and 
caused excessive pressure at the location of the seals. These factors 
must be considered by the mine operator to determine if a situation 
exists that will cause pressure piling, resulting in pressures above 
120 psi. If this situation exists, then seal strengths must be designed 
to an adequate level above 120 psi, as determined by the professional 
engineer.
    MSHA expects that mine operators will fully evaluate potential 
ignition sources, potential methane concentrations, and potential 
oxygen concentrations in the sealed areas to determine if detonation 
could occur. Mine operators should consider whether a high energy 
ignition source exists in the sealed area, whether extensive volumes of 
homogeneous mixtures of explosive methane concentrations may exist, and 
whether sufficient oxygen may be present in the sealed area.
    MSHA received several comments on the USACE's Draft Report. The 
report details the USACE's efforts to mathematically model the methane 
explosion at the Sago Mine and potentially establish the seal 
overpressures. The report recommended that additional research was 
needed to refine the models in order to better predict an explosion 
pattern.
    Commenters stated that computational fluid dynamics modeling could 
be used effectively to compare the effect of different variables on 
explosions, but that this type of modeling cannot accurately predict 
conditions. According to one commenter, their data collection and 
analysis of an actual gob composition is highly non-homogeneous, and 
the chance of methane gas detonation in a coal mine is almost zero. 
Therefore, this commenter stated that the 120-psi criterion in the ETS 
is adequate.
    Final Sec. Sec.  75.335(a)(1)(i) and (a)(2)(i) include requirements 
that seal designs must resist explosions of specific duration and 
intensity. The duration and intensity is characterized in pressure-time 
curves. A pressure-time curve gives engineers a mechanism to perform a 
dynamic analysis or to derive a dynamic load factor that they can use 
in a static analysis of a design. The pressure-time curves in Figures 1 
and 2 yield a dynamic load factor (DLF) of 2.0, which is the 
theoretical maximum (Structures to Resist the Effects of Accidental 
Explosions, Department of the Army, Report TM 5-1300, November 1990) 
(1990 Department of the Army Report). Holding the applied pressure for 
at least four seconds assures that a seal could be loaded elastically 
at a DLF of 2.0 (1990 Department of the Army Report). The instantaneous 
release of the overpressure load after at least four seconds gives 
engineers a criterion to address the rebound effect that would occur in 
the seal after the explosive force was removed. Under this final rule, 
a professional engineer could submit, for MSHA approval, a unique 
design that is able to withstand the prescribed design criteria.
    Figures 1 and 2 are the 50-psi and 120-psi pressure-time curves to 
be used for seal design.

[[Page 21186]]

[GRAPHIC] [TIFF OMITTED] TR18AP08.009

[GRAPHIC] [TIFF OMITTED] TR18AP08.010

    Several commenters requested a more prescriptive design standard 
identifying minimum overpressures. MSHA believes that a more 
prescriptive standard would eliminate ambiguity and result in greater 
protection of miners. In response to these comments and for clarity, 
final Sec. Sec.  75.335(a)(1)(i) and (a)(2)(i) provide specific 
pressure-time curves for certain seal designs.
    Some commenters requested that they be allowed to use seals 
constructed to separate the active longwall panel from the longwall 
panel previously mined. These commenters stated that such seals protect 
miners from explosions and help control spontaneous combustion, which 
has historically been a problem in the western U.S. mines. MSHA's 
enforcement policy under the ETS is consistent with the prescriptive 
design requirements in final Sec. Sec.  75.335(a)(1)(ii) and (a)(2)(ii) 
for these types of seals. These provisions allow seals to be designed 
using pressure-time curves that characterize an explosion having 
pressure venting and slower pressure rise times. Such pressure-time 
curves are published in the 2007 NIOSH Final Report.
    Both NIOSH 50-psi and 120-psi pressure-time curves for these seals 
yield a dynamic load factor of 1.0. The caved roof gob adjacent to 
seals used to separate the active longwall panel from the longwall 
panel previously mined minimizes run-up distances, which may otherwise 
be long enough to generate steeper rise times on either pressure pulse. 
Thus, both pressure-time curves enable engineers to analyze these seal 
designs based upon a dynamic analysis or a static, uniform pressure, 
which is equal to the peak overpressure in the applicable pressure-time 
curve. Figures 3 and 4 are the 50-psi and 120-psi pressure-time curves 
that can be used for the design of seals that separate the active 
longwall panel from the longwall panel previously mined.

[[Page 21187]]

[GRAPHIC] [TIFF OMITTED] TR18AP08.011

[GRAPHIC] [TIFF OMITTED] TR18AP08.012

    Several commenters asked that explosion wave mitigation procedures 
be allowed in lieu of seal designs to withstand overpressures greater 
than 120-psi. Based on MSHA's knowledge and experience, if a seal is to 
withstand overpressures at the design seal strength, then wave 
mitigation methods may not provide effective protection. Most wave 
mitigation techniques are designed for a one-time use, after which they 
do not offer any quantifiable resistance to explosion overpressure. 
While wave mitigation methods are not discouraged by MSHA, wave 
mitigation alone cannot be used to meet the requirements of the 
standard.
    Several commenters inquired about a safety factor in the seal 
designs. Some commenters believed that the seal design requirement in 
the ETS included a safety factor of two. Like the ETS, this final rule 
does not require a safety factor in any seal designs. As mentioned 
above, for static-equivalent seal designs using either of the two 
prescribed pressure-time curves having an instantaneous rise, a Dynamic 
Load Factor (DLF) of 2 would be applied to the peak overpressure. The 
DLF is multiplied by the peak overpressure for a static-equivalent 
overpressure for which the seal should be designed to resist. For 
example, a 120-psi seal designed with a static-equivalent procedure 
would have to withstand a design static overpressure of 240 psi. The 
two prescribed pressure-time curves that are permitted for use with 
seals constructed to separate the active longwall panel from the 
longwall panel previously mined have a DLF of 1. A DLF is not a factor 
of safety. It is a ratio used to equate a dynamic load with a static 
load for design purposes. Professional engineers are expected to 
incorporate load factors in their designs, in addition to the DLF, in 
accordance with current prudent structural engineering practices.
    Many commenters questioned why Mitchell-Barrett seal designs were 
not permitted under the ETS. Some commenters stated that Mitchell-
Barrett seals were tested by NIOSH and that they are capable of holding 
a static load over 95 psi. This maximum 95 psi overpressure was 
generated in a small-volume chamber behind the tested seal and was not 
generated by an explosion pressure wave traveling down a mine opening 
at the Lake Lynn Experimental Mine, as seals had been tested 
previously. NIOSH attempted to establish equivalency of a small-volume 
chamber to the full-scale explosion tests. NIOSH did not establish 
equivalency between the two types of tests. Also, the pressure-time 
curve in this final rule for 50-psi seals incorporates a DLF of 2 and 
results in a static equivalent load of 100 psi. This static equivalent 
load is greater than the 95 psi static load that NIOSH measured. 
Mitchell-Barrett seals that were tested

[[Page 21188]]

by NIOSH would not be permitted under this final rule for 50-psi seals 
requiring a DLF of 2.0.
    One commenter stated that the ETS would cause existing seals in 
three mines operated by the mine operator to be replaced with 50-psi 
rated seals and that replacement of the existing seals would be costly. 
The final rule does not require replacement of existing seals; rather, 
for existing seals, it requires operators to monitor methane and oxygen 
concentration levels and to maintain an inert atmosphere in the sealed 
area.
    Another commenter stated that the turnkey costs for seals used in 
the company's mines ranged from $12,000 to $25,000 and stated that MSHA 
had severely understated costs. However, the Agency's cost estimates 
are weighted averages of the costs for various types of seals. MSHA's 
estimated turnkey costs range from approximately $7,370 to $25,000 for 
50 psi seals and $11,330 to $38,550 for 120 psi seals. The commenter's 
costs come within the range of seal costs MSHA used to develop its cost 
estimates.
2. Section 75.335(b) Seal Design Applications
    Final Sec.  75.335(b) renumbers and revises ETS Sec.  75.336(a). It 
requires that seal design applications be based on either engineering 
design applications or full-scale explosion tests. The final rule 
permits the applicant to use other equivalent means of physical testing 
in lieu of full-scale explosion tests. The final rule also requires 
that seal design applications from seal manufacturers or mine operators 
be submitted for approval to MSHA's Office of Technical Support, 
Pittsburgh Safety and Health Technology Center, P.O. Box 18233, 
Cochrans Mill Road, Pittsburgh, PA 15236.
    Final Sec.  75.335(b)(1), like the ETS, sets forth specific 
requirements for an engineering design application. Under final Sec.  
75.335(b)(1)(i), an engineering design application must address the 
following: Gas sampling pipes, water drainage systems, methods to 
reduce air leakage, pressure-time curve, fire resistance 
characteristics, flame spread index, entry size, engineering design and 
analysis, elasticity of design, material properties, construction 
specifications, quality control, design references, and other 
information related to seal construction.
    Section 75.335(b)(1)(i) has been revised to include elasticity of 
design in the engineering design application. MSHA has included this 
requirement in the final rule for clarity. It is based on the 2007 
NIOSH Final Report and on MSHA's experience with seal design approvals 
under the ETS. NIOSH notes in the 2007 NIOSH Final Report that repeated 
pressure waves will likely impact the seal structure. Applications for 
seals designed for overpressures of 120 psi or greater must address 
elasticity in their design in order to withstand repeated, independent 
overpressures. This is consistent with current prudent engineering 
practices and with MSHA's seal approval process under the ETS. 
Addressing elasticity in seal design does not require a higher seal 
strength than that under the ETS. The final rule is consistent with 
MSHA's approved seal designs under the ETS. This final rule retains the 
other requirements of the ETS.
    Final Sec.  75.335(b)(1)(ii), like the ETS, requires that an 
engineering design application be certified by a professional engineer 
that the design of the seal is in accordance with current, prudent 
engineering practices. In addition, it clarifies the ETS requirement 
and specifies that the professional engineer certify that the seal 
design is applicable to conditions in an underground coal mine. In the 
ETS, MSHA discussed the engineering decisions and actions that must be 
made by and must be the responsibility of the professional engineer. 
Those included (1) the selection or development of design standards or 
methods, and materials to be used in seal construction; (2) the 
development and preparation of the structural analyses and design 
computations, drawings, and specifications; (3) the selection or 
development of techniques or methods of testing to be used in 
evaluating materials used either during seal construction or following 
completion of seal construction; and (4) the development of 
construction procedures. This final rule clarifies MSHA's intent that a 
seal design must reliably function given a set of specific conditions 
in an underground coal mine, and that a professional engineer must 
certify that the seal design is applicable to conditions in an 
underground coal mine.
    Several commenters stated that professional engineers who are 
required to comply with the engineering design application requirements 
in the ETS could lose complete dominion and control over the design of 
a seal. A commenter stated that West Virginia state law requires a 
professional engineer to maintain complete direction and control over 
all specifications, reports, drawings, plans, design information, and 
calculations to be certified. Commenters raised an issue concerning a 
seal designed by MSHA but requiring certification by a professional 
engineer. Under the ETS, this particular seal approval required a 
separate review and certification by a professional engineer before it 
could be used. However, the professional engineer may also use that 
particular design as basis for a new seal design and submit it to MSHA 
for approval.
    A commenter stated that the design of mine seals for use in West 
Virginia is engineering work and requires that it be done by a 
registered West Virginia professional engineer. MSHA accepts the 
certification of a professional engineer from any state and allows that 
certification to be used in other states. Each state is responsible for 
enforcing its rules and regulations.
    Another commenter stated that because field conditions change the 
professional engineer must be allowed to make the necessary field 
changes to meet those conditions in order to protect the public safety. 
MSHA acknowledges that some field conditions may change but because of 
the importance and complexity of the seal designs, the final rule does 
not permit field changes. Like the ETS, the final rule allows the mine 
operator to make revisions to the original approved design by 
submitting those changes that are certified by a professional engineer 
to MSHA's office of Technical Support for approval.
    Final Sec.  75.335(b)(1)(iii) revises ETS Sec.  75.336(a)(1)(iii) 
and requires that an engineering design application include a summary 
of the installation procedures related to seal construction. Based on 
MSHA's field experience under the ETS, the requirement for a summary of 
installation procedures is more appropriate than that in the ETS for 
specific information to be included in a Seal Design Table. Under the 
final rule, the summary should include all of the information necessary 
to construct a seal including quality control and other necessary 
information. The application must list provisions that specify quality 
control procedures for construction and include requirements for 
material sampling and testing. Material testing should be conducted by 
a certified laboratory and by qualified personnel. The certification 
for the laboratory must be from a professional organization such as the 
International Organization for Standardization (ISO) and the personnel 
must be able to demonstrate qualifications to ensure proper quality 
control testing. MSHA's experiences under the ETS reveal that some 
information included in the seal design application is proprietary. 
Although this information is required to be submitted to Technical 
Support for evaluation of

[[Page 21189]]

the design, it is not necessary to include it in the ventilation plan 
for approval by the District Manager. The requirement for the summary 
information will eliminate the need to disseminate any proprietary 
information. It will provide the District Manager with information 
needed to approve the seal design in the ventilation plan.
    Final Sec.  75.335(b)(2) requires that seal design applications can 
be based on full-scale explosion tests or equivalent means of physical 
testing. During discussions with MSHA on alternatives to full-scale 
testing, NIOSH indicated that equivalent testing conditions can be 
represented in suitable hydrostatic test chambers similar to those at 
the NIOSH Lake Lynn Experimental mine. MSHA believes that an equivalent 
means of physical testing, that has at least the same level of 
confidence as full-scale explosion testing, is an acceptable means of 
compliance and the Agency has included it in the final rule.
    Final Sec.  75.335(b)(2)(i), like ETS Sec.  75.336(a)(2)(i), 
requires certification by a professional engineer that the testing was 
done in accordance with current, prudent engineering practices for 
construction in a coal mine. This final rule deletes the requirement in 
the ETS that the professional engineer be knowledgable in structural 
engineering. MSHA deleted this requirement because there is no 
certification available to assure that a professional engineer is 
knowledgable in structural engineering. MSHA's experience with seal 
design approvals under the ETS reveals that the Professional Engineers 
who successfully submit seal designs are knowledgable in structural 
engineering. MSHA received one comment on this provision which 
recommended the words ``knowledgable in structural engineering'' be 
removed.
    Final Sec.  75.335(b)(2)(ii), like ETS Sec.  75.336(a)(2)(ii), 
requires the applicant to provide technical information related to the 
methods and material used to construct and test the seals. MSHA 
received no comments on this provision.
    Final Sec.  75.335(b)(2)(iii) requires that the application include 
supporting documentation. This clarifies ETS Sec.  75.336(a)(2)(iii) 
that required proper documentation. The term ``supporting'' more 
accurately describes the type of documentation required. This 
documentation includes: Engineering analyses, construction drawings and 
specifications, and data that address seal material, fire resistance 
and flame-spread index. The applicant must establish the materials and 
material properties required for adequate seal construction. 
Construction documentation is required to assure that the seals are 
properly built and reliable to address air leakage, and to verify that 
the material properties of the seal will meet the specified strength 
criteria. MSHA received no comments on this provision.
    Final Sec.  75.335(b)(2)(iv), like ETS Sec.  75.336(a)(2)(iv), 
requires the application to include an engineering analysis addressing 
differences between the seal support during test conditions and the 
range of test conditions in a coal mine. MSHA received no comments on 
this provision.
    Final Sec.  75.335(b)(2)(v) revises ETS Sec.  75.336(a)(2)(v) and 
requires that a summary of the installation procedures be included in 
the application. This requires that applicants submit more appropriate 
information in the form of a summary of installation procedures rather 
than specific information included in a Seal Design Table as required 
by the ETS. This summary should include the installation procedures 
related to mine specific seal construction. For example, it would 
include the maximum entry width and height for which the specific 
design is applicable, the specified strength of the seal material, the 
thickness of the seal, and the reinforcement and anchorage requirements 
for the seal. Additional information may be provided at the discretion 
of the Professional Engineer. MSHA received no comments on this 
provision.
    Final Sec.  75.335(b)(3), like ETS Sec.  75.336(a)(3), provides 
that MSHA will notify the applicant if additional information or 
testing is required. It also requires the applicant to provide this 
information, arrange any additional or repeat tests, and provide prior 
notification to MSHA of the location, date, and time of such tests. 
MSHA received no comments on this provision.
    Final Sec.  75.335(b)(4), like ETS Sec.  75.336(a)(4), provides 
that MSHA will notify the applicant, in writing, whether the design is 
approved or denied. It also provides that if the design is denied, MSHA 
will specify, in writing, the deficiencies of the application, or 
necessary revisions. MSHA received no comments on this provision.
    Final Sec.  75.335(b)(5), like ETS Sec.  75.336(a)(5), requires 
that once the seal design is approved, the approval holder must 
promptly notify MSHA, in writing, of all deficiencies of which they 
become aware. MSHA received no comments on this provision.
3. Section 75.335(c) Seal installation approval
    Final Sec.  75.335(c), like ETS Sec.  75.336(b), requires that the 
installation of the approved seal design be approved in the ventilation 
plan.
    Final Sec.  75.335(c)(1), like the ETS, requires the mine operator 
to retain the seal design approval and installation information for as 
long as the seal is needed to serve the purpose for which it was built. 
One commenter stated the requirement to retain approval and 
installation information for an indefinite period places an onerous 
burden on both the professional engineer and the mine operator, and 
suggested that the final rule include a definite duration for retaining 
this information. Based on MSHA's experience under the ETS, the 
requirement for approval and installation information provides a 
reliable reference should any problems occur during the service life of 
the seal. This provides valuable information as to how the seal was 
constructed and identifies the person responsible for certifying that 
the provisions in the approved seal design were addressed. In some 
instances, this information may enable persons to question individuals 
responsible for designing and constructing the seal to gain an insight 
as to the circumstances surrounding the construction and identify any 
problems that may have been encountered during the construction. 
Accordingly, this provision remains unchanged from the ETS.
    Final Sec.  75.335(c)(2), like the ETS, requires that the mine 
operator designate a professional engineer to conduct or have oversight 
of seal installation and certify that the provisions in the approved 
seal design specified in this section have been addressed and are 
applicable to the conditions in the mine. This final rule also requires 
that a copy of the certification be submitted to the District Manager 
with the information provided in final Sec.  75.335(c)(3) and that a 
copy of the certification be retained for as long as the seal is needed 
to serve the purpose for which it was built.
    One commenter supported this provision and stated that creating 
accountability in the construction process is a critical component if 
MSHA is to assure that coal operators take very seriously their 
obligation to provide a safe workplace with properly designed and 
constructed seals.
    Several commenters opposed this provision. They stated that the 
requirement to conduct or have oversight of seal installation should be 
deleted because it would be expensive, difficult because there are many 
variables in the construction process, and unnecessary because a mine 
operator must also certify construction. Some commenters stated that a

[[Page 21190]]

professional engineer's function is the design of a seal, not oversight 
of the construction. Several commenters stated that the provision would 
require a professional engineer to be on site prior to, during, and 
following construction of every seal to insure that all parameters are 
met and that would be unnecessary.
    Under the final rule, MSHA does not intend that the professional 
engineer take part in the construction process or be at the seal 
installation site during the entire construction process. MSHA stated 
its intent with respect to this requirement at the public hearings. 
MSHA's existing enforcement policy states that the professional 
engineer must inspect the set of seals during construction as part of 
the oversight and certification required by ETS Sec.  75.336(b)(2). To 
accomplish this oversight, MSHA would expect the professional engineer 
to: (1) Verify that the seal application is suitable for the specific 
conditions, (2) confirm that the site preparation is adequate, (3) 
confirm that the workforce is adequately trained to properly build the 
seals, (4) verify that the correct materials and procedures are being 
used to construct the seal, and (5) confirm that adequate quality 
controls are in place and are being followed. The professional engineer 
however, does not have to be onsite the entire time that seals are 
being built.
    Based on the Agency's knowledge and experience, MSHA has determined 
that the oversight by the professional engineer, who would be most 
familiar with the seal design, will help assure that appropriate seal 
design implementation and related analyses are performed properly. In 
addition, it will assure that seals are constructed according to the 
drawings and specifications of a professional engineer.
    Final Sec.  75.335(c)(3), like the ETS, lists specific information 
that a mine operator must address in the ventilation plan. The 
information will be used by the District Manager to evaluate a seal 
installation and determine whether the seal design is appropriate for a 
particular site.
    Final Sec.  75.335(c)(3)(i), like the ETS, requires that mine 
operators include the MSHA Technical Support Approval Number of the 
seal design in the ventilation plan. MSHA did not receive any comments 
on this section. This final rule is unchanged from the ETS.
    Final Sec.  75.335(c)(3)(ii) revises ETS Sec.  
75.336(b)(3)(iii)(D). It requires a summary of the installation 
procedures for approval to be included in the ventilation plan. This 
final rule is derived from the ETS requirement that the mine operator 
specify construction techniques for each type of seal. It revises the 
ETS requirement to be consistent with the language in final Sec.  
75.335(b)(1)(iii). The information required in this final rule, 
however, is essentially the same as that required in the ETS. Examples 
of information required by this provision include: Maximum entry width 
and height for which the design is applicable; specified strength of 
the seal; construction steps; and reinforcement and foundation 
anchorage requirements. In addition, when frame work is used, 
information should specify frame work size, spacing and materials used, 
a description of how the frame work is erected, size of other material 
used, such as concrete block size, wood products used and spacing, and, 
if needed, an anchorage table for rebar showing lengths, hole size, and 
other material used with the rebar. If hitching is required, 
information should specify hitching location, width and depth, 
calibration of equipment where required, sequence of pouring materials 
and thickness, sequence and type of roof support used, surface 
preparation, a description of the material pouring techniques and how 
cold joints may or may not be permitted, set back distances, a diagram 
of the water drainage system and air sampling installation, methods for 
preventing water retention during the curing process, rockdust removal 
from rib at the seal site, thickness of the seal, and other additional 
information in the seal design application.
    Final Sec.  75.335(c)(3)(iii) revises the ETS. It requires that 
mine operators provide, in the ventilation plan, a mine map of the area 
to be sealed and proposed seal locations that include the deepest 
points of penetration prior to sealing. This final rule revises the ETS 
by requiring that locations include the deepest points of penetration 
prior to sealing. This provision will help assure that the area was 
surveyed, a map of the area to be sealed was completed and the map was 
submitted by the mine operator. In addition, this final rule requires 
that the mine map be certified by a professional engineer or a 
professional land surveyor. It revises the ETS by including a 
professional land surveyor to certify the mine map to be consistent 
with existing Sec.  75.1201 which permits a professional land surveyor 
to certify the mine map.
    Final Sec.  75.335(c)(3)(iv), like the ETS, requires that mine 
operators submit specific mine site information in the ventilation 
plan. Final Sec.  75.335(c)(3)(iv)(A) requires that the type of seal be 
included in the ventilation plan. MSHA did not receive any comments on 
this provision.
    Final Sec.  75.335(c)(3)(iv)(B), like the ETS, requires mine 
operators to include information in the ventilation plan on the safety 
precautions taken prior to seals achieving design strength. Some 
commenters stated that this provision should require withdrawal of 
miners. According to commenters, this would be consistent with NIOSH's 
recommendation that miners be withdrawn from the affected area until 
seals reach design strength and the atmosphere in the sealed areas 
reaches an inert status. Other comments stated that withdrawal is not 
necessary because the sealed areas contain no likely ignition source, 
and if an inert atmosphere is present, uncured seals do not present an 
imminent danger as there is no explosion potential. In addition, some 
of these commenters stated that withdrawal of miners during seal curing 
time, which could be up to 28 days, would be too costly.
    Based on MSHA's knowledge and experience under the ETS, miners 
could be exposed to the dangers of an explosion prior to seals 
achieving their design strength. Accordingly, MSHA believes that safety 
precautions need to be taken prior to seals achieving design strength. 
Safety precautions could include withdrawing miners from the entire 
mine or other area approved by the District Manager. They could also 
include the use of seals that reach their design strength in 
considerably less time than 28 days. In addition, the mine operator 
could inert the atmosphere prior to or during seal installation. If an 
inert atmosphere is present behind seals that have not reached their 
design strength, miners would not need to be withdrawn from the 
affected area. This provision remains unchanged from the ETS.
    Final Sec.  75.335(c)(3)(iv)(C) revises the ETS. It requires that 
the mine operator provide information in the ventilation plan on 
methods used to address site-specific conditions that may affect the 
strength and applicability of the seal, including set-back distances. 
The set-back distance, which is the distance from the corner of a 
pillar block to a seal, is critical to the long term stability and 
protection of a seal. Although the ETS did not specifically address 
set-back distances, many professional engineers included this concept 
in their design applications.
    Based on MSHA's experience under the ETS, professional engineers 
designing seals have listed a minimum set-back distance of 10 feet when 
applying for a seal design approval in most instances. MSHA believes,

[[Page 21191]]

however, that set-back distances need to be addressed on a mine-by-mine 
basis. Some coal is softer or harder than others; and the overburden 
varies, which has an effect on the stability of the coal seam pillar. 
This means that some coal pillars will remain more or less stable than 
others over a long period of time. It is also possible to artificially 
reinforce the stability of less stable coal pillars, for example, by 
injecting materials into the pillars. Therefore, MSHA is including a 
requirement that the set-back distance of a seal be addressed in the 
mine ventilation plan during the seal plan approval process.
    Final Sec.  75.335(c)(3)(iv)(D), like the ETS, requires the mine 
operator to submit information in the ventilation plan on site 
preparation. MSHA did not receive any comments on this provision.
    Final Sec.  75.335(c)(3)(iv)(E), like the ETS, requires the mine 
operator to include information on the sequence of seal installations 
in the ventilation plan. MSHA did not receive any comments on this 
provision.
    Final Sec.  75.335(c)(3)(iv)(F), like the ETS, requires that the 
mine operator provide information in the ventilation plan on the 
projected date of completion of each set of seals. MSHA did not receive 
any comments on this provision.
    Final Sec.  75.335(c)(3)(iv)(G), like the ETS, requires the mine 
operator to provide information in the ventilation plan on the 
supplemental roof support inby and outby each seal. MSHA did not 
receive any comments on this provision.
    Final Sec.  75.335(c)(3)(iv)(H), like the ETS, requires the mine 
operator to provide information in the ventilation plan on the water 
flow estimation and dimensions of the water drainage system through the 
seals. MSHA did not receive any comments on this provision.
    Final Sec.  75.335(c)(3)(iv)(I), like the ETS, requires that the 
mine operator provide information in the ventilation plan on the 
methods used to ventilate the outby face of seals once completed. MSHA 
did not receive any comments on this provision.
    Final Sec.  75.335(c)(3)(iv)(J), like the ETS, requires the mine 
operator to provide information in the ventilation plan on the methods 
and materials used to maintain each type of seal. MSHA did not receive 
any comments on this provision.
    Final Sec.  75.335(c)(3)(iv)(K), like the ETS, requires the mine 
operator to provide information in the ventilation plan on methods used 
to address shafts and boreholes in the sealed area. MSHA did not 
receive any comments on this provision.
    Final Sec.  75.335(c)(3)(iv)(L) is derived from ETS Sec.  
75.335(a)(3)(iv). This final rule requires the mine operator to provide 
information in the ventilation plan on an assessment of potential for 
overpressures greater than 120 psi in the sealed area. ETS Sec.  
75.335(a)(3)(iv) required the mine operator to revise the ventilation 
plan when conditions that would necessitate a seal greater than 120 psi 
are encountered. This final rule is consistent with the ETS. It 
includes this provision to assure that the mine operator evaluates the 
area to be sealed and addresses the need for seals greater than 120 
psi.
    Final Sec.  75.335(c)(3)(iv)(M) renumbers and clarifies ETS Sec.  
75.335(b)(5)(ii). It requires mine operators to provide information in 
the ventilation plan on additional sampling locations. This final rule 
is consistent with ETS Sec.  75.335(b)(5)(ii), which required the 
location of sampling points to be included in the mine operator's 
action plan. Under this final rule, additional sampling locations could 
include sampling through boreholes and capped shafts with vent pipes.
    Final Sec.  75.335(c)(3)(iv)(N), like the ETS, requires the mine 
operator to provide, in the ventilation plan, any additional 
information required by the District Manager. This final rule will help 
assure that any new developments in technology or any problems related 
to site-specific conditions in sealing may be addressed by the mine 
operator through the ventilation plan. MSHA did not receive any 
comments on this provision.

B. Section 75.336 Sampling and Monitoring Requirements

    Final Sec.  75.336, derived from ETS Sec.  75.335(b), revises and 
renumbers sampling and monitoring requirements for sealed atmospheres. 
In the final rule, the terms ``sampling'' and ``monitoring'' are used 
interchangeably. The final rule deletes the requirement in the ETS for 
mine operators using seals designed to withstand less than 120 psi to 
develop and follow a protocol to monitor methane and oxygen 
concentrations in sealed atmospheres. The ETS required that the 
protocol be approved by the District Manager in the ventilation plan. 
Requirements to maintain and restore an inert atmosphere in the sealed 
area are discussed in final Sec.  75.336(b); requirements for sampling 
pipes are discussed in final Sec.  75.337(g). Requirements for welding, 
cutting and soldering are discussed in final Sec.  75.337(f); 
requirements for water drainage systems are discussed in final Sec.  
75.337(h); and requirements for training of certified persons 
conducting sampling are discussed in final Sec.  75.338(a).
    Section 75.336(a) of the final rule retains the requirement in ETS 
Sec.  75.335(b) for a certified person, as defined under existing Sec.  
75.100, to monitor sealed atmospheres for methane and oxygen 
concentrations. Unlike the ETS, the final rule requires sealed 
atmospheres to be monitored through each sampling pipe and approved 
sampling location whether seals are ingassing or outgassing. Training 
requirements for certified persons are addressed in final Sec.  
75.338(a) and are unchanged from the ETS.
    Final Sec. Sec.  75.336(a)(1)(i) through (iii) address ETS 
requirements for sampling frequencies, including initial sampling 
periods and sampling on a continuing basis. Atmospheres with seals less 
than 120 psi constructed prior to October 20, 2008, and atmospheres 
with seals of less than 120 psi constructed after October 20, 2008 must 
be sampled through each sampling pipe and approved location at least 
every 24 hours. Under the final rule, the operator may request that the 
District Manager approve different frequencies and locations in the 
ventilation plan. Under the final rule, seals of 120 psi or greater 
must be monitored until they reach their design strength. After they 
reach their design strength, the final rule does not require the 
atmosphere in these sealed areas to be monitored and maintained inert.
    Final Sec.  75.336(a)(2) is derived from ETS Sec. Sec.  
75.335(b)(1) and (b)(5) and requires the mine operator to evaluate the 
atmosphere in the sealed area to determine whether sampling through 
required sampling pipes under final Sec.  75.337(g) provides 
appropriate sampling locations. The final rule specifies the conditions 
under which the evaluation must be conducted. When the evaluation 
results indicate the need for additional sampling locations, the mine 
operator must establish additional sampling locations and include them 
in the ventilation plan for approval by the District Manager.
    Final Sec.  75.336(a)(3) requires mine operators with an approved 
ventilation plan addressing spontaneous combustion under existing Sec.  
75.334(f) to monitor sealed atmospheres in accordance with the plan.
    Final Sec.  75.336(a)(4) is derived from ETS Sec.  75.335(b)(5)(vi) 
and allows the District Manager to approve the use of a continuous 
monitoring system in lieu of monitoring provisions in the final rule.
    Final Sec.  75.336(b)(1), like ETS Sec.  75.335(b)(3), defines an 
inert atmosphere as one in which the oxygen concentration is less than 
10 percent, or

[[Page 21192]]

the methane concentration is less than 3.0 percent or greater than 20.0 
percent. Final Sec.  75.336(b)(2) addresses corrective action necessary 
if the atmosphere is not inert. It requires that when a sealed 
atmosphere with less than 120-psi seals is not inert, the mine operator 
must take immediate action to reestablish an inert atmosphere and 
monitor the sealed atmosphere every 24 hours until it is restored to an 
inert status.
    Final Sec.  75.336(c) revises and clarifies ETS Sec.  75.335(b)(4) 
and specifies when persons must be withdrawn from the mine due to a 
hazardous atmosphere in the sealed area.
    Final Sec.  75.336(d) clarifies existing MSHA policy that allows 
the operator to request that the District Manager approve in the 
ventilation plan a different oxygen concentration if the atmosphere in 
the sealed area contains carbon dioxide. It also addresses sealed areas 
where inert gas has been injected, and sampling methods and equipment.
    Final Sec. Sec.  75.336(e)(1) and (e)(2) are the same as ETS 
Sec. Sec.  75.335(b)(6) and (b)(7) and include requirements for 
recording sampling results and any hazardous condition found in 
accordance with existing Sec.  75.363.
1. Section 75.336(a)
    Section 75.336(a) retains the requirement in ETS Sec.  75.335(b) 
for a certified person, pursuant to Sec.  75.100, to monitor sealed 
atmospheres. The final rule continues to require the certified person 
to monitor the sealed area for methane and oxygen concentrations. Under 
the final rule, unlike the ETS, sealed atmospheres must be monitored 
whether seals are ingassing or outgassing. Mine operators must also 
determine the direction of air leakage during monitoring which will 
indicate whether seals are ingassing or outgassing. Seals outgas when 
the pressure in the sealed area exceeds the pressure on the outby side 
of the sealed area. Seals ingas when the pressure outby the sealed area 
exceeds the pressure in the sealed area.
    ETS Sec.  75.335(b)(1) required mine operators to sample sealed 
atmospheres only when seals were outgassing. MSHA requested comments 
regarding: its sampling approach; sampling frequency; sampling only 
when a seal is outgassing; whether a different sampling approach would 
be more appropriate for the final rule, such as when seals are 
ingassing; and information and experiences of the mining community 
concerning sampling sealed areas.
    Commenters' views were divided regarding appropriate conditions for 
monitoring seals, especially on the issue of outgassing and/or 
ingassing. MSHA received comments in support of the ETS strategy of 
requiring monitoring when seals were outgassing, while some other 
comments supported monitoring whether outgassing or ingassing. Several 
commenters suggested that sampling only during outgassing is inadequate 
to protect miners, since a greater concern exists when a seal is 
ingassing and adds oxygen to a fuel-rich environment in the sealed 
area. One commenter stated that ingassing creates zones of explosive 
methane-air mixtures and is more dangerous than when the seals are 
outgassing. A number of other commenters stated that sampling inby an 
ingassing seal or a seal that is in barometric pressure transition is a 
recipe for inaccurate sampling, and MSHA should not require sampling 
during ingassing. Finally, one commenter who supported sampling when 
seals are outgassing recommended that balance chambers could reduce 
incidences of barometric pressure changes exceeding the ventilating 
pressure produced by main mine fans causing seals to ingas. According 
to this commenter, the sealed atmosphere continues to change at least 
at the perimeter of the sealed area, and in some parts of the country, 
this change occurs on a daily or even more frequent basis. This 
commenter also suggested that MSHA provide incentives for mine 
operators such as allowing them to use lower-strength seals than 
required in the ETS. According to the commenter, these incentives 
should include allowing lower strength seals where balance chambers are 
used. MSHA acknowledges that a number of sealed atmospheres fluctuate 
from outgassing to ingassing on a frequent basis. MSHA believes that 
the sampling strategy under the final rule, based on ingassing or 
outgassing, would remove the need for balance chambers.
    The Agency has reviewed the comments, hearing transcripts, data and 
other information contained in the rulemaking record regarding sampling 
and monitoring. MSHA also reviewed the Agency's enforcement history and 
field experience with implementation under the ETS. The Agency believes 
that sealed atmospheres should be monitored whether outgassing or 
ingassing. Since promulgation of the ETS, some operators have 
experienced significant delays in monitoring sealed areas, especially 
during the 14-day baseline period and while seals are reaching their 
design strength. The preamble to the ETS stated:

    If the seal is ingassing during the examination, the certified 
person must attempt to take a sample during the next weekly 
examination. After a second attempt is made and the seal is still 
ingassing, attempts must be made daily until the seal outgases. If 
repeated sampling indicates that a seal is not likely to outgas, 
then the mine operator must submit an alternative protocol to the 
District Manager. (72 FR at 28802)

    At the time of promulgation of the ETS, MSHA did not envision that 
the sampling and monitoring procedure would result in the significant 
delays that have been experienced in the mining industry. MSHA 
inspectors also experienced delays in monitoring sealed atmospheres 
because of having to wait for seals to outgas before a sample could be 
taken. Also, limiting monitoring to outgassing affected the operators' 
ability to promptly implement the ETS monitoring requirements for 
determining whether the sealed atmosphere had reached the explosive 
range. After a review of the rulemaking record, the Agency does not 
believe that the record evidence supports limiting monitoring sealed 
areas to when seals are outgassing. In response to comments and in 
light of its own experience, the Agency has revised the monitoring 
requirement in this final rule to require mine operators to monitor 
sealed atmospheres whether seals are outgassing or ingassing. MSHA 
expects the final rule provisions to resolve many existing problems 
with monitoring sealed areas and to enhance safety and health of 
underground coal miners.
    Final Sec. Sec.  75.336(a)(1) requires monitoring through each 
sampling pipe and at each approved sampling location. Under Sec.  
75.336(a)(1)(i), mine operators must sample atmospheres with seals of 
120 psi or greater until the design strength is reached, after which 
time they may cease sampling. Initial sampling for all newly-
constructed seals is necessary to protect miners if an explosive 
atmosphere forms behind seals before they reach their design strength.
    Under Sec.  75.336(a)(1)(ii) of this final rule, like the ETS, the 
mine operator must monitor for methane and oxygen and maintain an inert 
atmosphere in the sealed area when using seals less than 120 psi 
constructed prior to the date of this final rule. Final Sec.  
75.336(a)(1)(iii) requires that atmospheres with seals of less than 120 
psi constructed after the date of this final rule must be monitored and 
the atmosphere must be maintained inert.
    Final Sec. Sec.  75.336(a)(1)(ii) and (iii) allow the operator to 
request that the District Manager approve different sampling locations 
and frequencies in the ventilation plan provided at least one sample is 
taken at each set of seals at least every 7 days. Under final

[[Page 21193]]

Sec.  75.335(a)(1)(iii) for less than 120 psi seals constructed after 
April 18, 2008, the District Manager cannot approve different sampling 
locations and frequencies in the ventilation plan until after a minimum 
of 14 days and after seals have reached design strength. MSHA will 
consider pertinent information supplied by the mine operator, such as 
the results of the 14-day sampling period and any other previous 
sampling results, in an operators'' request to change sampling 
locations and frequencies. The 7-day interval is the same as the ETS 
monitoring frequency and is consistent with weekly examinations 
required in existing Sec.  75.364. MSHA believes the sealed atmosphere 
must be sampled at least every 7 days in the event seal leakage, strata 
fracturing, roof convergence or another problem has developed and is 
affecting the sealed atmosphere. Under the final rule, MSHA emphasizes 
that mine operators must monitor sealed atmospheres at a frequency of 
every 24 hours unless the District Manager approves a different 
frequency in the ventilation plan. For newly constructed seals of less 
than 120 psi, the final rule requires a 14-day sampling period before 
the District Manager may approve different sampling locations and 
frequencies. The final rule deletes ETS Sec.  75.335(b)(5)(iii) which 
required mine operators to specify procedures in the sampling protocol 
to establish a baseline analysis of oxygen and methane concentrations 
at each sampling point over a 14-day sampling period to be approved in 
the ventilation plan. In the final rule, in response to commenters and 
for clarity, MSHA has included specific parameters for sampling sealed 
atmospheres. As such, there is no need for a sampling protocol.
    Several commenters said that the atmosphere behind all seals should 
be monitored and maintained inert. One commenter stated that sealed 
areas cannot be adequately monitored or maintained inert; therefore, 
all seals must be designed to withstand an explosion. Another commenter 
stated that monitoring is inadequate to protect miners and that it 
provides a false sense of security. MSHA believes that monitoring 
sealed areas informs the mine operator of the presence of potentially 
hazardous gases in sealed areas. Under the final rule, use of seals 
designed for less than 120-psi overpressure requires the mine operator 
to maintain an inert atmosphere in the sealed area since explosions 
cannot occur within inert atmospheres. MSHA believes that in mines 
which liberate significant volumes of methane, the atmosphere in sealed 
areas may become inert naturally. In mines that produce very small 
volumes of methane, the atmosphere in sealed areas may never become 
explosive. However, some mines may need to use other means to inert the 
atmosphere in the sealed area, such as injecting inert gas or pressure 
balancing of the ventilation system; or injecting material into the 
strata surrounding the seals to reduce leakage. These methods could 
inert the atmosphere in the sealed area. Other mines may need to 
construct new seals that are 120 psi or greater in front of all 
existing seals. MSHA's existing standards at Sec.  75.334(a)(1) and 
(a)(2) require that worked-out areas be sealed or ventilated.
    Commenters stated that the ETS sampling and monitoring requirements 
were confusing. A number of commenters criticized the need for District 
Manager approval of the sampling protocol. Several commenters said that 
there was no scientific basis for the monitoring, while others said 
that the final seal regulation should be more prescriptive. Several 
commenters criticized MSHA's weekly sampling intervals as being too 
lengthy to protect the miners. One commenter said that their data 
showed sealed areas never reach equilibrium and that barometric 
pressure changes continue to affect the sealed atmosphere. Commenters 
stated that when a sealed area has reached a stable atmospheric 
composition, weekly sampling is unnecessary.
    MSHA continues to believe that weekly samples are necessary to 
protect miners'' safety and health. Barometric pressure changes, 
ventilation changes, water accumulations, methane liberation, 
subsidence, cracked strata near seals, and other changes may render a 
previously inert atmosphere explosive. Periodic monitoring is necessary 
to detect these potentially hazardous conditions in the sealed area. 
The final rule, like the ETS, requires periodic sampling.
    Final Sec.  75.336(a)(2) clarifies MSHA's intent under ETS Sec.  
75.335(b) for the mine operator to have responsibility for evaluating 
the atmosphere in the sealed area to determine whether sampling through 
seal sampling pipes, in accordance with final Sec.  75.337(g), will 
provide an appropriate sample of the sealed atmosphere. Appropriate 
sampling must be capable of reliably detecting significant 
accumulations of explosive methane in the sealed area.
    MSHA specifies in the final rule when the mine operator must 
conduct the evaluation which includes: the planning phase for sealing 
the area; immediately after the minimum 14-day required sampling; when 
the mine ventilation system is reconfigured; if changes in the mine 
occur that could adversely affect the sealed area; or if the District 
Manager requests an evaluation. When the results of the evaluations 
indicate the need for additional sampling locations, the mine operator 
must provide the additional locations and have them approved in the 
ventilation plan. The District Manager may require additional sampling 
locations and frequencies in the ventilation plan.
    The mine operator shall evaluate the sealed area using the sampling 
results from the minimum 14-day required sampling and any other 
relevant information available to confirm that the initial evaluation 
is valid. A mine ventilation system reconfiguration may affect the 
direction of air leakage through seals and consequently alter the 
interpretation of sampling results in order to determine the inert 
status of the sealed atmosphere. The composition of the sealed 
atmosphere can be affected by changes in air currents, water 
accumulations, convergence, cracks in the strata leading to the 
surface, and the rate and/or location of methane liberation. These 
changes may affect the distribution of methane and oxygen concentration 
throughout the sealed area. The District Manager may request an 
evaluation based on other factors as appropriate.
    Many variables affect the atmospheric composition of the sealed 
area, including size, methane liberation, leakage, ventilation 
pressures, and barometric changes. Mine operators must analyze each 
sealed area when determining appropriate sampling locations and 
frequencies. If the mine operator's analysis indicates that sampling 
through seal sampling pipes does not render an appropriate evaluation 
of the sealed atmosphere, the mine operator must establish additional 
sampling locations and specify them in the ventilation plan for the 
District Manager's approval.
    Under the final rule, the District Manager may require additional 
sampling locations and sampling frequencies in the mine ventilation 
plan such as when MSHA sampling results differ from the operator's 
sampling results, or the District Manager's review of the mine 
operator's data indicates the atmosphere in the sealed area is not 
being adequately evaluated. In the ETS, the Agency expressed its intent 
that under ETS Sec.  75.335(b), mine operators had to evaluate the 
sealed atmosphere to determine whether additional sampling locations 
were necessary.

[[Page 21194]]

    In the ETS, MSHA also emphasized that all seals and the strata 
around them leak, resulting in an air exchange near the seal during 
barometric pressure changes. Seals may leak air into a methane-rich 
sealed atmosphere that can result in explosive methane concentrations. 
Due to this, MSHA stressed in the ETS the significance of obtaining 
appropriate samples of atmospheric conditions in the larger portion of 
the sealed area as opposed to the smaller area immediately inby the 
seal.
    Some commenters objected to the requirement in ETS Sec.  75.335(b) 
for the mine operators to obtain a representative sample solely through 
sampling pipes. MSHA acknowledges the limitations of the ETS sampling 
method for large sealed areas. While sampling a limited number of times 
or at a reduced frequency may result in an effective evaluation of the 
sealed area, additional sampling locations can be necessary to 
determine if a sealed atmosphere is inert. For instance, a sealed 
atmosphere may have one set of seals ingassing fresh air from the mine 
while another set of seals is outgassing high concentrations of 
methane. A transition zone exists where the atmosphere experiences an 
explosive range of methane between the two sets of seals. Thus, final 
Sec.  75.336(a)(2) addresses the mine operator's responsibility to 
include adequate sampling locations and frequencies in the ventilation 
plan.
    Several commenters stated that it is impractical to drill boreholes 
from the surface due to cost implications, surface topography, or land 
ownership. Although MSHA recognizes that there may be situations in 
which it may be impractical to drill boreholes from the surface, the 
Agency is aware that directional drilling from the surface or from 
within the mine is commonly practiced in the mining industry and may be 
used when topographic or land ownership problems are encountered. It is 
common practice in the mining industry to remove all persons from the 
affected area when the borehole approaches an unexamined or 
unventilated area. Other commenters supported a requirement for drilled 
boreholes to adequately monitor large or unusual sealed areas.
    A commenter suggested that it is unreasonable for MSHA to assume 
that localized samples, regardless of the technique, establish the 
inert status of the sealed area. MSHA believes that sampling through 
seals, supplemented with additional sampling locations, where 
necessary, provides a safe and feasible method of ascertaining 
atmospheric conditions in the sealed area. Final Sec.  75.336(a)(2) 
provides that the District Manager can require additional sampling 
locations, such as boreholes, and frequencies in a mine operator's 
ventilation plan.
    One commenter expressed that it is not a significant hazard when a 
large sealed area in a mine has explosive mixtures when sampled through 
pipes, because coalbed methane production wells located above the 
sealed area produce almost pure methane (greater than the upper 
explosive limit). MSHA believes that methane extracted from the gob 
vent borehole primarily comes from the strata above the active coal 
mine. (Mucho, T.P., W.P. Diamond, F. Garcia, J.D. Byars and S.L. Cario, 
Implications of Recent NIOSH Tracer Gas Studies on Bleeder and Gob Gas 
Ventilation Design, The Society of Mining Engineers Annual Meeting, 
2000). MSHA determined that boreholes used to sample sealed areas must 
be connected to the open entries within the sealed area. Degasification 
boreholes typically stop about 30 to 40 feet above the coal seam and do 
not extend into the sealed area and will not provide an accurate sample 
of the sealed atmosphere.
    Some commenters recommended a risk analysis of sealed areas rather 
than monitoring. As appropriate, mine operators may include an analysis 
of the risks in the sealed area in their evaluation of the sealed area 
for MSHA's consideration. An evaluation under final Sec.  75.336(a)(2) 
may include size of the sealed area, frequency of sampling, likelihood 
of spontaneous combustion, depth of the mine, and the patterns of 
methane liberation. However, the Agency concludes that the rulemaking 
record does not support a requirement of a risk analysis in lieu of 
monitoring. Monitoring of the sealed atmosphere in areas where seals 
less than 120 psi are used, and until the design strength is reached 
for seals of 120 psi or greater, provides optimum safety for miners 
because of the unforeseen changes that can occur within the sealed 
area.
    Final Sec.  75.336(a)(3) requires mine operators with an approved 
ventilation plan addressing spontaneous combustion under existing Sec.  
75.334(f) to sample the sealed area as specified in the approved 
ventilation plan. Section 75.334(f) addresses mines with a demonstrated 
history of spontaneous combustion and those located in coal seams 
determined to be susceptible to spontaneous combustion. It requires 
that the approved mine ventilation plan for these mines specify the 
measures that will be used to detect methane, carbon monoxide, and 
oxygen concentrations during and after pillar recovery, and in worked-
out areas where no pillars have been recovered; the actions that will 
be taken to protect miners from the hazards of spontaneous combustion; 
and the methods that will be used to control spontaneous combustion, 
accumulations of methane-air mixtures, other gases, dusts, and fumes in 
the worked-out area. Sampling and maintaining an inert atmosphere are 
critical in sealed areas in coal mines that are subject to spontaneous 
combustion of the coal seam due to this inherent ignition source.
    Several commenters stated that MSHA should continue to require mine 
operators to control spontaneous combustion in sealed areas through 
compliance with Sec.  75.334(f). These commenters stated that the 
sampling requirements of a spontaneous combustion plan should be more 
comprehensive than the requirements of Sec.  75.336 to safely manage 
the combustion potential. MSHA allows the spontaneous combustion 
monitoring requirements in the approved ventilation plan to be used in 
lieu of the monitoring requirements of this section which is more 
protective for miners.
    Final Sec.  75.336(a)(4), derived from ETS Sec.  75.335(b)(5)(vi), 
allows the District Manager to approve the use of a continuous 
monitoring system in lieu of the monitoring provisions in this section. 
A continuous monitoring system may include bundles of sampling tubes 
that sample a frequency of every few hours and monitor at numerous 
sampling locations in the sealed area. MSHA standards addressing 
atmospheric monitoring systems are in existing Sec.  75.351 and are 
applicable to belt air courses, primary escapeways, return air splits, 
and electrical installations. These standards do not address monitoring 
in sealed areas. The final rule broadens the scope and applicability of 
the ETS requirement in that it addresses continuous monitoring systems 
rather than atmospheric monitoring systems. Since promulgation of the 
ETS, MSHA does not believe that all of the provisions of Sec.  75.351, 
atmospheric monitoring systems, are applicable to monitoring sealed 
atmospheres.
    One commenter stated that MSHA did not adequately address 
continuous gas monitoring systems in the ETS. The final rule allows for 
use of these monitoring systems. Several commenters expressed that 
current atmospheric monitoring sensors could not be used in sealed 
areas due to calibration and maintenance requirements. The final rule 
deletes

[[Page 21195]]

reference to atmospheric monitoring systems.
    Mine operators using continuous monitoring systems to monitor 
sealed atmospheres must submit a revised ventilation plan to the 
District Manager. The District Manager will review the revised plan to 
assure that the continuous monitoring system will perform effectively. 
In making a decision to approve this system, MSHA expects the mine 
operator to address calibration, recordkeeping, oversight of the 
continuous monitoring system, maintenance features of the monitoring 
system and sampling locations.
2. Section 75.336(b)
    Final Sec. Sec.  75.336(b)(1) and 75.336(b)(2) address inert 
atmospheres in sealed areas. Section 75.336(b)(1), unchanged from ETS 
Sec.  75.335(b)(3), defines an inert atmosphere as one in which the 
oxygen concentration is less than 10.0 percent; the methane 
concentration is less than 3.0 percent; or the methane concentration is 
greater than 20.0 percent. MSHA has included a margin of safety in the 
definition of an inert atmosphere so that mine operators can address 
potential explosion hazards before having to withdraw miners. As the 
Agency stated in the ETS, the explosive range of methane is 5 to 15 
percent when the oxygen level is 12 percent or more (2007 NIOSH Draft 
Report) which are the traditional values used in the coal mining 
industry. According to the 2007 NIOSH Draft Report, methane is 
explosive in air when the concentration ranges from 5 percent to 15 
percent by volume. As in the ETS, to allow for the inaccuracy of 
methane and oxygen detection equipment and potential contamination of 
samples, oxygen less than 10.0 percent, methane concentration less than 
3.0 percent and methane concentration greater than 20.0 percent are 
used to determine an inert atmosphere.
    For atmospheres behind seals with design strengths less than 120-
psi, final Sec.  75.336(b)(2) requires the mine operator to take 
immediate action to restore the sealed atmosphere to an inert 
condition. Mine operators also must sample sealed atmospheres at least 
every 24 hours. In addition, MSHA requires withdrawal of miners when 
methane is between 4.5 and 17 percent and oxygen is 10 percent or 
greater.
    Some commenters stated that until seals ``cure'' all sealed 
atmospheres must be inert, including seals of 120 psi or greater, or 
miners must be withdrawn from the mine. A critical time period for 
seals is immediately after construction prior to seals reaching their 
design strength. Miners must be protected from the hazard of an 
explosive atmosphere behind seals prior to seals reaching their design 
strength. Under the final rule, hazardous conditions are controlled by 
frequently monitoring and maintaining an inert atmosphere or 
withdrawing miners from the mine. Under MSHA's final rule, mine 
operators must monitor and maintain an inert atmosphere behind all 
newly-constructed seals. After 120-psi seals or greater reach their 
design strength, they are not required to be monitored under Sec.  
75.336. MSHA noted in the ETS that its accident history covering mines 
in the United States does not include documentation of an explosion in 
an underground mine that has generated an overpressure greater than 120 
psi. One commenter addressing the final draft U.S. Army Corps of 
Engineers report stated that the chance of having a methane gas 
detonation in a coal mine is almost zero and further stated that with 
using actual gob compositions the constant volume explosion loads were 
found to not exceed 100 psi. Based on the Agency's experience under the 
ETS and other record evidence, the final rule does not require seals 
with a design strength of 120 psi or greater to be monitored after they 
reach their design strength.
    Several commenters stated that MSHA's definition of an inert 
atmosphere in the ETS was overly conservative and recommended the 
generally accepted definition of a non-explosive atmosphere of oxygen 
less than 12.0 percent, and methane less than 5.0 percent or greater 
than 15.0 percent. A commenter suggested an expanded explosion risk 
buffer zone based on a Queensland, Australia underground coal mining 
standard. Commenters also stated that MSHA should take a tiered 
approach to address varying levels of methane and oxygen in the sealed 
area. Some of these commenters used the term ``explosive buffer zone'' 
when addressing broader gas concentrations to incorporate a margin of 
safety into the definition of inert and protocol requirements in ETS 
Sec. Sec.  75.335(b)(4) and 75.335(b)(5). The ETS required an action 
plan for which mine operators were required to address hazards 
presented and actions to be taken when gas samples indicated that 
oxygen was 10.0 percent or greater and methane concentrations were 3.0 
percent or greater but less than 4.5 percent; 4.5 percent or greater 
but less than 17.0 percent; and 17.0 percent to 20.0 percent. Several 
commenters said that no buffer zones are necessary if a gas 
chromatograph is used to analyze the samples. MSHA believes that 
chromatographic analyses are more accurate than handheld instruments. 
MSHA also believes that handheld detectors can be an adequate sampling 
method to determine the methane and oxygen concentration at a sample 
location. The definition of an inert atmosphere in the final rule 
includes a margin of safety to account for sampling less than the 
entire sealed area and time-related changes in the sealed atmosphere.
    A number of commenters said that explosive atmospheres that 
periodically develop when the barometric pressure is rising or the 
seals are ingassing are not hazardous. The effects of ingassing depend 
on several factors including the duration and magnitude of the pressure 
differential across seals, leakage rates, and the typical methane 
concentration for the sealed area. Therefore, MSHA believes that 
hazards may exist when the seals are ingassing and the final rule is 
structured to address such hazards.
    Commenters objected to the ETS requirement for a 14-day baseline 
sampling period or questioned its benefit. MSHA considered these 
comments, but the final rule retains a 14-day initial sampling 
requirement for seals less than 120 psi constructed after April 18, 
2008. MSHA believes that monitoring of the sealed area during the 
initial 14-day period provides optimum safety for miners because of the 
unforeseen changes that can occur within the sealed area. For newly 
constructed seals, the final rule is structured so that mine operators 
can establish the appropriate number of sampling locations. Several 
commenters expressed concern with the alternative ventilation plan 
requirements for seals that only ingas or rarely outgas. MSHA has 
reexamined this issue and believes that monitoring and maintaining an 
inert atmosphere is protective only when the sealed area is inert at 
all times. The final rule requires mine operators to establish and 
maintain an inert atmosphere behind seals less than 120 psi.
    Some other commenters stated that all sealed atmospheres must be 
monitored and maintained inert. Another commenter said monitoring is 
not the answer and that MSHA must require stronger seals. The final 
rule is structured so that the mine operator can address unique 
characteristics of sealed areas through either monitoring and 
maintaining an inert atmosphere or using seals designed to address the 
potential overpressures which may develop in the sealed area.
    Another commenter stated that MSHA should require gas 
concentrations in the sealed area to be maintained sufficiently

[[Page 21196]]

outside the explosive range to prevent any excursions into the 
explosive zone during normal changes in barometric pressure. Finally, a 
commenter suggested that one way to reduce the possibility that a 
detonation may occur in the sealed area is to keep the methane air 
behind the seal far from the explosive range so that changes in 
pressure conditions due to foreseeable events are not possible. This 
commenter also stated that methane concentration greater than 50 
percent could assure that the methane range in the sealed area will not 
fall within the 5 to 15 percent explosive range. In addition, this 
commenter stated that the ETS required more frequent monitoring for 
specified ranges of gases, but the provision does not provide a margin 
of safety that would prevent swings into the explosive range for 
foreseeable events such as weather, will not prevent detonations, and 
sampling, regardless of the technique, will not confirm an inert status 
of the sealed area.
    The Agency's definition of an inert atmosphere incorporates a 
margin of safety which accounts for sampling less than the entire 
sealed area and time-related changes in the sealed atmosphere. MSHA 
believes that the increased sampling frequencies required by the final 
rule along with the definition of inert and the requirements for 
withdrawal of miners will provide appropriate and necessary protection 
of miners.
3. Section 75.336(c)
    Final Sec.  75.336(c) revises and clarifies ETS Sec. Sec.  
75.335(b)(4) and (b)(5) and addresses requirements for potentially 
explosive atmospheres in sealed areas with less than 120-psi seals. 
Final Sec.  75.336(c) requires that when a sample is taken from the 
sealed atmosphere with seals of less than 120 psi and the sample 
indicates that the oxygen concentration is 10 percent or greater and 
methane is between 4.5 percent and 17 percent, the mine operator must 
immediately take an additional sample and then immediately notify MSHA. 
In addition, final Sec.  75.336(c) requires that when the additional 
sample indicates that the oxygen concentration is 10 percent or greater 
and methane is between 4.5 percent and 17 percent, persons must be 
withdrawn from the affected area which is the entire mine or other 
affected area identified by the operator and approved by the District 
Manager in the ventilation plan, except those persons referred to in 
Sec.  104(c) of the Act. Under this final rule, the operator may 
identify areas in the ventilation plan to be approved by the District 
Manager where persons may be exempted from withdrawal. The operator's 
request must address the following factors regarding the location of 
seals in relation to: (1) Areas where persons work and travel in the 
mine; (2) escapeways and potential for damage to the escapeways; and 
(3) ventilation systems and controls in areas where persons work or 
travel and where ventilation is used for escapeways. The District 
Manager, in making a determination concerning the area where persons 
may be exempted from withdrawal, would take these factors into 
consideration. The operator's request shall also address the gas 
concentration of other sampling locations in the sealed area and other 
required information.
    Final Sec.  75.336(c) clarifies when miners may reenter the mine 
and requires the mine operator to have an approved and revised 
ventilation plan specifying the actions to be taken by the mine 
operator to protect miners.
    MSHA requested comments on the ETS action plan approach to 
potentially explosive sealed atmospheres and whether that approach 
provides adequate protection for miners. Several commenters stated that 
persons should not be withdrawn merely due to explosive samples in the 
sealed area and that other factors such as the size of the sealed area, 
roof and weather conditions, or the volume of non-inert atmosphere 
should be considered. Several commenters wanted MSHA to consider the 
possibility of defining safety zones around seals. Other commenters 
said that miners should unconditionally be evacuated from the mine when 
any sealed atmosphere is in the explosive range. Several commenters 
questioned whether an action plan could provide protection to miners 
which would be equivalent to withdrawal. One commenter suggested that 
rather than withdrawing miners, a ``safety zone,'' or a specific 
distance, should be established around seals with explosive 
atmospheres. A commenter stated that keeping miners underground with a 
sealed atmosphere within the explosive range is an unacceptable risk 
due to the enormous potential for a catastrophe if a seal fails.
    Some action plans approved under the ETS require the withdrawal of 
miners from the entire mine. MSHA now believes that some large mines 
with multiple fans, multiple shafts, multiple portals, or multiple 
escapeways may not require evacuation of the entire mine to protect 
miners from the hazards presented by an explosion in a sealed area. 
Accordingly, this final rule allows an operator to identify areas in 
the ventilation plan to be approved by the District Manager where 
persons may be exempted from withdrawal. The operator's request must 
address the factors in this provision of the final rule. For example, 
in a large mine, the District Manager may approve an area where persons 
may be exempted from withdrawal if: (1) The area where persons work or 
travel is remote from the sealed area; (2) the area is on separate air 
splits that would not be contaminated from the gaseous products of an 
explosion; and (3) those areas are served by escapeways that would not 
be impacted by an explosion.
    One commenter said that MSHA district offices do not have the 
resources to properly evaluate proposed action plans required by the 
ETS and the rule should provide specificity about the actions required 
to be taken by mine operators. Action plans are not required in the 
final rule. MSHA has replaced action plans with specific actions to be 
taken under certain circumstances.
    Several commenters said that withdrawal should only be required 
when oxygen levels in the sealed area exceeded 12 percent because this 
is the minimum oxygen level that will sustain an explosion at normal 
atmospheric pressure. Another commenter said that introduction of 
oxygen caused the formation of an explosive atmosphere. Other 
commenters said that the explosive gas range is too broad. Another 
commenter said the Queensland Australia regulation specifies, for 
continuous monitoring, the maximum oxygen concentration should be 8 
percent and the methane concentration should be less than 2.5 percent 
or greater than 22 percent. Several commenters said that withdrawal 
should only be required when the atmosphere in sealed area is in the 
explosive range of methane which they defined as 5 percent to 15 
percent.
    A commenter recommended using mapping software to generate isopach 
maps of methane concentration throughout the sealed area in order to 
determine potentially explosive zones. MSHA does not believe that 
isopach mapping software, based on arbitrary mathematical 
interpolations, will accurately represent the complex methane 
liberation, diffusion and convection processes in the sealed area in 
combination with leakage through or around seals to predict explosive 
zones with any degree of reliability.
    In the ETS, MSHA referenced the 2007 NIOSH Draft Report which 
stated that the explosive range is 5 to 15 percent when the oxygen 
level is 12 percent or more. NIOSH, in its Final Report, stated that 
methane is explosive in air when the concentration ranges

[[Page 21197]]

from 5 percent to 16 percent by volume. The NIOSH Final Report stated: 
``A desirable sealed area atmosphere, from a safety perspective is 
fuel-rich and oxygen-low, which is * * * less than 10% oxygen.'' The 
final rule continues to account for the inaccuracies of sampling and 
monitoring equipment, and for potential contamination of the gas 
sample. The final rule retains the methane range of 4.5 percent to 17.0 
percent with oxygen 10 percent or greater for withdrawal of miners as 
specified in the ETS. This range of methane concentration is slightly 
broader than the explosive range specified by NIOSH (2007 NIOSH Draft 
Report and ``Handbook for Methane Control in Mining,'' Information 
Circular 9486, 2006 (2006 NIOSH IC 9486), and ``Flammability of 
Methane, Propane, and Hydrogen Gases,'' Cashdollar (2000). The slightly 
broader range of methane includes a safety measure to help assure the 
mine operator has time to safely evacuate the mine. MSHA has considered 
these comments and continues to accept the methane in air mixtures 
provided by NIOSH as the most appropriate basis for the final rule. The 
levels in the final rule are the same as those provided in the ETS.
    The ETS allowed mine operators to take three samples at one hour 
intervals before requiring evacuation of the mine. Several commenters 
objected to this provision. A commenter suggested that three 
consecutive samples be taken at 24 hour intervals to allow the sealed 
area to react to changes in the barometer. MSHA believes that it is 
neither appropriate nor protective of miners' safety to allow them to 
remain underground two additional hours before a mine operator confirms 
a hazardous sealed atmosphere. The final rule requires that a second 
sample be taken immediately and that MSHA be immediately notified 
regardless of the results of the second sample.
4. Section 75.336(d)
    For sealed areas with a demonstrated history of carbon dioxide or 
where inert gas has been injected, final Sec.  75.336(d) allows the 
mine operator to use an alternative method to determine if a particular 
atmosphere is inert as defined in Sec.  75.336(b)(1). This provision 
also allows the mine operator to use an alternative method to determine 
when to withdraw miners as provided in Sec.  75.336(c). The mine 
operator shall address the specific levels of methane, carbon dioxide, 
nitrogen and oxygen in the ventilation plan; the sampling methods and 
equipment used; and the methods to evaluate these concentrations 
underground at the seals.
    Some commenters requested MSHA to consider carbon dioxide 
concentrations when making a determination for inert and explosive 
atmospheres, because it is slightly more effective at preventing an 
explosion than nitrogen in normal air. A commenter stated that it is 
unrealistic to ignore the effects of carbon dioxide on methane 
explosibility and that MSHA must let mine operators use both the Coward 
flammability triangle and Zabetakis nose curve to assess whether a 
sealed atmosphere is explosive. Commenters also requested that MSHA 
consider excess nitrogen concentrations when determining the sealed 
atmosphere.
    A methane explosion requires the presence of sufficient amounts of 
methane and oxygen. The presence of carbon dioxide and excess nitrogen 
affects the concentrations of oxygen and methane needed for an 
explosion to occur. The two most common gases used for purposes of 
maintaining a sealed area inert are nitrogen and carbon dioxide. Both 
gases may be obtained as cryogenic liquids transported to the mine site 
on tanker trucks. Nitrogen may also be extracted from compressed air 
using filter technology and carbon dioxide may be produced as the 
exhaust gas from combustion processes (Tomlinson boiler, diesel engine 
or jet engine). Both the ETS and final rule implicitly consider 
nitrogen as an inert gas. Fresh air contains 78% nitrogen and nitrogen 
is typically the most prevalent gas in sealed atmospheres. If 
additional nitrogen is injected in a sealed atmosphere, it helps move 
the gas mixture toward an inert status merely by diluting and rendering 
harmless the methane and oxygen levels. Carbon dioxide is slightly more 
effective at producing an inert atmosphere than nitrogen.
    This final rule allows mine operators to use carbon dioxide and 
nitrogen levels to determine how to manage the sealed atmosphere. If 
the mine operator chooses an alternative method to determine if the 
sealed atmosphere is inert, the operator must specify the types of 
instruments that will be used to measure the gas levels and how these 
more complicated evaluations will be performed at the seal. Because of 
the critical nature of these measurements and determinations, the use 
of gas chromatographs and computers located on the surface is not 
practical except where continuous monitoring systems are used. This 
surface analytical equipment cannot be used since this final rule 
requires that a second sample be taken and analyzed immediately after 
any near explosive gas concentrations are identified.
    Although the Zabetakis nose curve or the Coward flammability 
triangle is designed to show whether a methane mixture is explosive 
after inert gas is added, the nose curve or flammability triangle is 
not intended for the purpose of establishing an inert atmosphere under 
this final rule or the explosibility range contained in the final rule.
    The concentration of gases for methane in the nose curve and 
flammability triangle ranges from approximately 5% to 15%. The nose 
curve and flammability triangle were not designed to account for the 
methane ranges specified in the final rule of 4.5% to 17% where a 
safety factor is used. In addition, the use of the R-Ratio, or ratio of 
methane to total combustibles, to compensate for the safety factor is 
not appropriate. The alternative gas concentrations of methane, carbon 
dioxide, nitrogen and oxygen must be based on sound scientific 
principles. For example, operators may consider the Bureau of Mines 
Bulletin 503 (Coward, H.F. and G.W. Jones, ``Limits of Flammability of 
Gases and Vapors,'' Bulletin 503, U.S. Dept. of the Interior, Bureau of 
Mines, 1952). The alternative gas concentrations must provide the same 
levels of protection to the miners as the gas concentrations specified 
in Sec.  75.336(b) and (c) of this final rule.
    MSHA intends that samples of gas concentrations be analyzed 
promptly. At present, handheld detectors are available to measure 
carbon dioxide, methane and oxygen. The operator shall address several 
related issues in the ventilation plan including handheld equipment and 
methods to take these measurements underground and methods to make the 
calculations necessary to evaluate the gas concentrations at the seal. 
The operator should also include methods to ensure the reliability of 
the sampling equipment, the training of the certified persons who must 
take these samples and perform these calculations, a system to validate 
these determinations and the expanded recordkeeping requirements 
(additional gas concentrations).
5. Section 75.336(e)
    Final Sec.  75.336(e), like ETS Sec.  75.335(b)(6) and (b)(7), 
requires that the mine operator promptly record sampling results and 
that these records be maintained at the mine for at least one year. 
MSHA received no comments on this provision.

[[Page 21198]]

C. Section 75.337 Construction and repair of seals

    Final Sec.  75.337 is derived from the ETS requirements on 
construction and repair of seals.
1. Section 75.337(a)
    Final Sec.  75.337(a) clarifies the ETS and requires mine operators 
to maintain and repair seals to protect miners from hazards of sealed 
areas. MSHA is including this provision in this final rule in response 
to comments concerning seal repairs. This final rule addresses non-
structural repairs only. Non-structural repairs are those that are 
related to general maintenance and include: excessive air leakage 
through and around seals; repair of minor cracks; spalling of seal 
coating; water drainage systems; and sampling pipes. One commenter 
expressed concern that seals may become inaccessible, deteriorate, 
weaken, and be impossible to repair. This section does not apply to 
seals that require structural repairs. MSHA will continue to require 
that seals in need of structural repairs be replaced since they would 
no longer serve their necessary function. Seals, with the exception of 
seals used to separate the active longwall panel from the panel 
previously mined that are inby the longwall face, must be maintained 
accessible or be replaced.
2. Section 75.337(b)
    Final Sec.  75.337(b) renumbers Sec.  75.337(a) of the ETS, and 
specifies requirements that a mine operator must follow prior to 
sealing.
    Under final Sec.  75.337(b)(1), mine operators must remove 
insulated cables from the area to be sealed. Final Sec.  75.337(b)(1) 
clarifies the ETS and requires that mine operators remove batteries and 
other potential electric ignition sources from the area to be sealed. 
Because an electric arc can occur if a length of insulated cable were 
inductively coupled to an electromagnetic pulse such as a lightning 
strike, this final rule reduces the hazard of an explosion caused by an 
electric discharge.
    Several commenters stated that the removal of insulated cables is 
unnecessary, infeasible, unrealistic and can be unsafe. One commenter 
suggested that grounding the ends of a cable may safeguard cables that 
cannot be removed. Other commenters stated that as mine operators 
complete mining activities in an area, they recover the more useful 
cables and may only leave behind damaged or deteriorated cables. 
Another commenter stated that there can be miles of cables to pumps or 
electric installations that must continue to run to within days or 
hours of final sealing, and that it would be impossible to remove these 
cables prior to sealing. One commenter suggested that cable removal 
would be unnecessary if seals are constructed to withstand explosive 
forces. One commenter suggested that the final rule include a provision 
for removing batteries from the area to be sealed.
    To reduce the hazard of an explosion from an electric discharge, 
and to assure miners' safety, MSHA believes that it is necessary to 
remove cables, batteries, and other potential ignition sources prior to 
sealing unless it is not safe to do so. Other potential ignition 
sources include motors, transformers and electromagnetic devices. 
Potential electric ignition sources that may expose miners to dangerous 
conditions, such as those that are buried under a roof fall, would not 
have to be removed.
    Based on MSHA's knowledge and experience, if one end of an 
insulated cable is grounded and one is not, a potential ignition source 
remains. Also, a potential ignition source remains even if both ends of 
a cable are grounded because the condition of the conductors within the 
cable would not be known. Based on MSHA testing, cable cannot generally 
be considered safe by grounding either one or both ends.
    The final rule includes a clarifying change that if ignition 
sources cannot be safely removed from the area to be sealed, seals must 
be constructed to at least 120 psi. NIOSH indicated in their 2007 NIOSH 
Final Seal Report that a 50 psi peak overpressure could occur in a 
limited-volume, unconfined situation. Leaving a potential ignition 
source, such as a cable, in the sealed area could increase the 
probability that larger pockets of gas, which may be undetected through 
sampling, could be ignited, resulting in an explosion. An explosion in 
a larger area could result in overpressures greater than 50 psi. 
Therefore, the final rule provides appropriate protection for miners if 
ignition sources cannot be safely removed from the area to be sealed. 
The installation of at least 120 psi seals would provide protection for 
miners and prevent the explosion in the sealed area from propagating to 
the active workings of the mine.
    Final Sec.  75.337(b)(2), like the ETS, requires removal of 
metallic objects that pass through or across seals. Screens, straps, 
rails, and channels are examples of the types of metallic objects that 
are required to be removed under this final rule. In addition, this 
final rule does not include the exception in the ETS for metal sampling 
pipes, water drainage pipes, and form ties. Removal of metallic objects 
before seals are built reduces the hazard of methane explosions and 
improves miner safety.
    Several commenters suggested that metal sampling pipes, water 
drainage pipes, and form ties need not be removed because nonmetallic 
materials can be used as alternatives. MSHA agrees. Alternative 
nonmetallic materials exist and can be used for gas sampling pipes, 
water drainage systems, and form ties. The use of these alternative 
materials will reduce methane explosion hazards and enhance miner 
safety.
    Several commenters stated that removal of metallic roof support is 
hazardous. One commenter noted that an accident occurred during removal 
of wire mesh at a seal location. Based on MSHA's experience, removal of 
metallic roof support can be accomplished safely so long as appropriate 
precautions are taken. Under the final rule, the best option would be 
for an operator to plan the location of the seals and the roof 
supports, such as cribs and non-metallic mesh, to be used in the area 
to be sealed.
    One commenter requested clarification of the hazards associated 
with metallic roof mesh or mats that are grounded. Based on MSHA's 
experience, metallic roof mesh or mats are not always adequately 
grounded. In addition, metallic roof mesh or mats are potential 
conductive paths into the sealed area and need to be removed.
    One commenter stated that MSHA should not require removal of de-
gassing, inerting, or pre-sealing ventilation pipes that may be needed 
to effectively control the gob atmosphere. Based on MSHA's experience, 
these metallic objects can provide a conduit for electric current to 
enter the sealed area and ignite methane/air mixtures. Removal of these 
objects before seals are built reduces the hazard of methane explosions 
and improves miner safety. Therefore, in response to its request for 
comments in the ETS on information concerning the removal of metallic 
objects, the final rule requires removal of metallic objects through or 
across seals.
    Final Sec.  75.337(b)(3) is new. It requires mine operators to 
breach or remove all stoppings in the first crosscut inby the seals 
immediately prior to sealing the area. This procedure is a recognized 
common practice in the coal mining industry.
    One commenter stated that monitoring could easily provide a false 
sense of security. Another commenter said that sampling behind one seal 
in a set would not be able to detect a pocket

[[Page 21199]]

of explosive gas that may exist. In response to commenters'' concerns, 
the final rule includes the requirement to remove or breach the 
stopping in the first connecting crosscuts inby seal locations. Under 
MSHA's experience, breaching or removing stoppings allows the same 
atmosphere to exist immediately inby each seal as exists throughout the 
sealed area. Ventilation stoppings in the first connecting crosscut 
inby the seal locations are used to maintain ventilation, through the 
area to be sealed, during seal construction. These stoppings should not 
be breached or removed until immediately prior to installing the final 
seal. The timing of the breaching or removing of stoppings is critical 
and should be addressed in the mine ventilation plan under Sec.  
75.335(c)(3)(iv)(N).
3. Section 75.337(c)
    Final Sec.  75.337(c), renumbers ETS Sec.  75.337(b), and requires 
a certified person designated by the mine operator to directly 
supervise seal construction and repair. Existing Sec.  75.100 defines a 
certified person as one certified by the Secretary of Labor or the 
State in which the coal mine is located. Following explosions at the 
Sago and Darby mines in 2006, MSHA inspected seals in underground coal 
mines across the country and concluded that some seals were not 
correctly built. The supervision requirement will help assure that seal 
construction and repair are performed correctly.
    Under final Sec.  75.337(c)(1), the certified person must examine 
each seal site immediately prior to construction or repair to assure 
that the site is in accordance with the approved ventilation plan. 
Under final Sec.  75.337(c)(2), the certified person must examine each 
seal under construction or repair during each shift to assure that the 
seal is being constructed or repaired in accordance with the approved 
ventilation plan. Under final Sec.  75.337(c)(3), the certified person 
must examine each seal upon completion of construction or repair to 
assure that construction or repair is in accordance with the approved 
ventilation plan.
    Some commenters objected to these provisions stating that it was 
unnecessary and burdensome for the certified person to supervise the 
entire construction process. They stated that trained qualified persons 
should be permitted to repair or construct seals in accordance with the 
approved plan and that the certified person can then conduct an 
examination to assure the plan was followed. Other commenters, however, 
supported a requirement for a certified person to be on site during 
each step of seal construction.
    MSHA believes that a certified person needs to be in the vicinity 
of the seal site to address problems and questions during seal 
construction or repair. Under the final rule, MSHA does not intend that 
a certified person continuously observe construction or repair of all 
seals in a set. The certified person should be available at each seal 
site during the shift to assure proper construction or repair.
    Some commenters expressed concern regarding potential conflicts 
created by requiring that certain tasks be performed, under the ETS, by 
both professional engineers and certified persons. Based on MSHA's 
experience under the ETS, the Agency has not encountered any potential 
conflicts and does not believe any are likely to arise. The role of the 
professional engineer to have oversight of seal installation is more 
fully discussed in Sec.  75.335(c).
    Final Sec.  75.337(c)(4), like the ETS, requires that the certified 
person certify by initials, date, and time that the examinations were 
made. MSHA did not receive any comments on this provision.
    Final Sec.  75.337(c)(5), like the ETS, requires that the certified 
person make a record of the examination at the completion of any shift 
during which an examination was conducted, and include each deficiency 
and the corrective action taken. The record 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, and the record must be kept at the mine for one year. 
This recordkeeping requirement allows MSHA and other persons to 
determine that examinations have been conducted, that results are 
valid, and that deficiencies in site preparation, construction and 
repairs were found and corrected. In addition, the record must identify 
seal completion dates.
    One commenter stated that countersigning simply identifies the 
person to blame in the event of an accident or seal failure. Another 
commenter stated that countersigning was unnecessary. Historically, the 
countersigning requirement has been an integral part of MSHA's 
enforcement of coal mining standards. It is consistent with other 
recordkeeping requirements in 30 CFR part 75; such as Sec. Sec.  75.360 
(pre-shift examination) and 75.361 (supplemental examination), 75.362 
(on-shift examination), 75.363 (hazardous conditions), and 75.364 
(weekly examination). The countersignature must be made by the end of 
the mine foreman's or equivalent mine official's next regularly 
scheduled working shift. If the mine foreman or equivalent mine 
official is absent, the person acting in that position would review and 
countersign the record. Based on MSHA's experience under the ETS, this 
provision assures that a mine foreman or equivalent mine official is 
responsible for seal installation.
4. Section 75.337(d)
    Final Sec.  75.337(d) renumbers Sec.  75.337(c) of the ETS, and 
requires that upon completion of construction of each seal, a senior 
mine management official, such as a mine manager or superintendent, 
certify that the construction, installation, and materials used were in 
accordance with the approved mine ventilation plan. It also requires 
the mine operator to retain the certification for as long as the seal 
is needed to serve the purpose for which it was built.
    Some commenters stated that this certification was unnecessarily 
duplicative of the certification required by the certified person 
during construction and repair and the certification required by the 
professional engineer during the plan approval process. Some commenters 
stated that the certification requirement by a senior mine official is 
unreasonable and redundant because the official may not have expertise 
to make certification; the official may not have knowledge unless 
present during construction; a professional engineer is required to 
have ``oversight''; the certified person directly supervises 
construction and makes a record of the exam; and the mine foreman 
countersigns the certified person's record. Other commenters suggested 
modification of the ETS requirement to either allow a senior mine 
official to rely on reports from the professional engineer and 
certified person, or to allow a senior mine management official to 
countersign the official seal record book.
    Based on MSHA's experience regarding methane explosions in sealed 
areas and MSHA's experience regarding the same certification 
requirements under the ETS, the Agency believes that some amount of 
redundancy is necessary in the review of these critical seal 
construction tasks; this provides an added margin of safety for miners. 
Certifications by certified persons, and senior mine management 
officials protect miners by helping assure that the seal is correctly 
designed and constructed.

[[Page 21200]]

5. Section 75.337(e)
    Final Sec.  75.337(e) renumbers Sec.  75.337(d) of the ETS, and 
remains essentially unchanged. Final Sec.  75.337(e)(1) requires the 
mine operator to notify the District Manager between two and fourteen 
days prior to commencement of seal construction. This final rule 
revises the ETS requirement to notify the MSHA local field office.
    One commenter supported the notification requirement stating that 
it is necessary so that MSHA can oversee seal construction. This 
commenter recommended that an MSHA inspector be present at least part 
of the time during seal construction.
    One commenter opposed the notification requirement. This commenter 
stated that it is inefficient to require contacting MSHA since an MSHA 
inspector is at the mine over 150 days during the year. In the final 
rule, MSHA has retained the notification requirement because the Agency 
believes that it is necessary and it is also responsive to comments.
    This requirement gives MSHA the opportunity to observe seal 
construction and to help assure that the construction, installation and 
materials were in accordance with the ventilation plan approved by 
MSHA. The requirement to notify the District Manager establishes 
consistency with other MSHA notification requirements. Like other 
notification provisions, the District Manager either contacts the 
appropriate field office or inspectors from the District Office may 
make the inspection.
    Final Sec.  75.337(e)(2), like the ETS, requires the mine operator 
to notify the MSHA District Manager, in writing, within five days of 
completion of each set of seals and provide a copy of the certification 
required in Sec.  75.337(d) of this section. The purpose of this 
provision is to give the District Manager notice of completed seal 
construction. The period immediately following construction of the seal 
is the time during which seals are achieving full strength and the 
atmosphere inby the seals may be transitioning into or through a 
potentially explosive methane/air mixture. During this critical time 
period, the District Manager may decide to inspect the seals or sample 
the sealed area.
    Final Sec.  75.337(e)(3), like the ETS, requires the mine operator 
to submit a copy of quality control test results for seal material 
properties specified in Sec.  75.335 to the District Manager. To 
clarify the performance required, the final rule includes a requirement 
that the test results be submitted within 30 days of completion of the 
tests. The final rule, like the ETS, requires that test results include 
all tests of seal construction materials. Some commenters expressed 
concern over a specified time requirement for the submission of quality 
control tests results because some results are often not available for 
weeks after the tests are completed. Sampling must be continued on a 
24-hour basis for all seals until MSHA receives the test results and 
determines that they are adequate. Based on MSHA's experience under the 
ETS, MSHA believes that a 30-day period will provide sufficient time to 
obtain results and assures that test results are submitted promptly. 
MSHA has not experienced any problems with this timeframe under the 
ETS.
6. Section 75.337(f)
    Final Sec.  75.337(f) renumbers Sec.  75.335(c) of the ETS, and 
like the ETS, prohibits welding, cutting, and soldering with an arc or 
flame within 150 feet of a seal. This final rule revises the ETS by 
allowing this work within 150 feet of a seal unless it is not safe to 
do so. The operator may request that the District Manager approve a 
different location in the ventilation plan. The purpose of this 
provision is to protect miners from the hazards of open flames near 
seals. A methane enriched atmosphere can leak through the seal, 
accumulate out by the seal, and if ignited, the flame can propagate 
into the sealed area causing an explosion.
    The 150-foot limit in the final rule is consistent with an existing 
MSHA requirement in Sec.  75.1002(a) that non-permissible equipment be 
excluded within 150 feet of pillar workings or longwall faces. To 
measure the 150 feet, MSHA recommends that mine operators use the 
longstanding industry practice of following the shortest distance that 
air can travel (tight string distance) through crosscuts, entries or 
other openings (MSHA Program Policy Manual, Volume V, Subpart J 
(February 2003)).
    In response to MSHA's request for comments, some commenters 
supported and others opposed the provision. Commenters who supported 
the provision stated that the protection was necessary to prevent 
another explosion like the one that occurred at the Darby Mine. 
Commenters who opposed the provision stated that it was too restrictive 
and unenforceable under current mining conditions. Some of these 
commenters stated that the provision could significantly interrupt 
mining operations where the next entry from the seal contains a pre-
existing belt, belt-drive, shop area, travelway, or track. In addition, 
some commenters requested that MSHA consider that some belt drives in 
underground coal mines have separate splits of large quantities of air, 
and that compliance flexibility should be included in the final rule to 
accommodate different mining conditions.
    In response to comments and based on MSHA's experience under the 
ETS, MSHA has revised the ETS. An operator may request that the 
District Manager approve in the ventilation plan welding, cutting, and 
soldering with an arc or flame within 150 feet of a seal. The 
operator's request must address methods the mine operator will use to 
continuously monitor atmospheric conditions in the sealed area during 
welding or burning; the airflow conditions in and around the work area; 
the rock dust and water application methods; the availability of fire 
extinguishers on hand; the procedures to maintain safe conditions, and 
other relevant factors. MSHA believes that welding, cutting and 
soldering with an arc or flame near a sealed area may be allowed 
depending upon mining conditions at the mine, and that determination 
should be made by the District Manager on a case-by-case basis.
7. Section 75.337(g)
    Final Sec.  75.337(g) renumbers and revises Sec.  75.335(d) of the 
ETS. Final Sec.  75.337(g)(1) requires one non-metallic sampling pipe 
in each seal that extends into the center of the first connecting 
crosscut inby the seal. The final rule requires that if an open 
crosscut does not exist, the sampling pipe shall extend into the center 
of the length of the open entry inby the seal. The requirement that 
only non-metallic materials be used for sampling pipes is consistent 
with other provisions of this final rule that require the removal of 
metallic objects through or across seals.
    MSHA received many comments regarding the ETS requirements on the 
locations and number of sampling pipes. Many commenters questioned the 
requirement of two sampling pipes in each seal. They stated that it is 
doubtful that two sampling pipes in each seal will provide much 
additional information and they could result in conflicting and 
confusing information. In addition, several commenters disagreed with 
the need for a sampling pipe in each seal. Some commenters questioned 
whether a representative sample could be obtained by using a sampling 
pipe through a seal. Several commenters suggested putting a sampling 
pipe at the high and low points of the seals. One commenter stated that 
the location and number of

[[Page 21201]]

sampling pipes should be based on the mining conditions.
    MSHA reviewed sampling data collected under the ETS 14-day baseline 
requirement and other sampling data, including that associated with the 
Agency's citations and withdrawal orders. Based on this review, MSHA 
believes that one sampling pipe provides adequate information and that 
two sampling pipes in each seal are not necessary and could result in 
conflicting and confusing information. In addition, the Agency's 
evaluation of its sampling data from the 15-foot pipe found significant 
variation of methane concentrations at different seals in the set and 
between sets of seals for the same sealed area. MSHA attributes this to 
different ventilation pressures at the various seals and differences in 
leakage characteristics through the ribs and strata surrounding the 
seals (cracks, joints, etc), depending on the location of the seals. 
MSHA believes that sampling points with a longer pipe located within 
the first connecting crosscut will provide a more representative sample 
of the sealed area because this atmosphere is less likely to be 
affected by ingassing. In addition, this sampling location is less 
susceptible to swings in oxygen levels associated with changes in 
barometric pressure. Based on comments, data, and Agency experience, 
MSHA has revised the ETS to remove the requirement that a sampling pipe 
extend 15 feet into the sealed area.
    One commenter stated that gob isolation seals are installed in 
crosscuts immediately behind the longwall face and, therefore, it would 
be impossible to meet the requirements to extend one tube into the 
center of the first connecting crosscut inby the seal as that 
intersection will no longer exist once the longwall mines pass the 
crosscut where the seal is to be installed. In addition, this commenter 
stated that installing sampling pipes near the intersection is not 
practical as crosscut conditions often quickly deteriorate on the gob 
side of the seal. Under circumstances where gob isolation seals will 
have no connecting crosscut inby the seal, or under similar 
circumstances, the sampling pipe must be extended to the center of the 
expected open space to obtain a sample that is representative of the 
gas in the sealed area. In addition, under circumstances where crosscut 
conditions may deteriorate, sampling pipes should be located so that 
they are subjected to the least amount of deterioration. Even if some 
pipes deteriorate, it is unlikely that all pipes will deteriorate at 
every sampling location. In addition, under this final rule, the 
District Manager may require additional sampling locations in the 
ventilation plan under Sec.  75.336.
    Final Sec.  75.337(g)(2) retains the ETS requirement that each 
sampling pipe be equipped with a shut-off valve and appropriate 
fittings for taking gas samples. MSHA received no comments on this 
provision.
    Final Sec.  75.337(g)(3) is new. It requires the sampling pipes to 
be labeled to indicate the location of the sampling points when more 
than one sampling pipe is required under Sec.  75.337(g)(4).
    Final Sec.  75.337(g)(4) is derived from and is consistent with 
existing MSHA enforcement policy under the ETS. If a new seal is 
constructed to replace or reinforce an existing seal with a sampling 
pipe, final Sec.  75.337(g)(4) requires the sampling pipe in the 
existing seal to be extended through the new seal. It also requires 
that an additional sampling pipe be installed through each new seal to 
sample the area between seals, as specified in the approved ventilation 
plan. Final Sec.  75.337(g)(4) is consistent with existing MSHA policy 
that addresses requirements for placement of the sampling pipe when a 
new seal is constructed outby an existing seal to replace or reinforce 
an existing seal.
    Final Sec.  75.337(g)(4) was added to clarify requirements gained 
as a result of MSHA's experience under the ETS concerning construction 
of new seals immediately outby existing seals that had been either 
damaged, or had had significant structural defects. In addition, some 
operators of mines with potentially explosive atmospheres decided to 
construct new 120-psi seals outby existing seals under the ETS. Under 
these circumstances, MSHA found that if a new seal is constructed as an 
extension or reinforcement of an existing seal, there may be no 
additional sealed area to sample. In addition, most existing seals have 
only one sampling pipe per set of seals and some sets of seals that 
predate MSHA's 1992 ventilation standards may have no sampling pipes.
    If the new seals are close to the existing seals, an explosion in 
the area inby the old seals could damage the new seals. By maintaining 
the area inert between the new seals and the old seals, the possibility 
of an explosion between the seals effectively is eliminated. MSHA 
considered requiring the mine operator to drill holes through existing 
seals to install sampling pipes. MSHA rejected this approach due to the 
possibility of sparking or frictional ignition associated with 
drilling.
    The final rule requires that sampling pipes in existing seals be 
extended through the new seals to permit the sampling of the atmosphere 
inby the existing seals. If there is a space between the new seals and 
the existing seals, this area will need to be sampled and maintained 
inert and will require a sample pipe through each new seal. If the 
space between the seals does not include a connecting crosscut, the new 
sampling pipe must be extended to the center of the open space.
8. Section 75.337(h)
    Final Sec.  75.337(h) renumbers and revises Sec.  75.335(e) of the 
ETS. It requires that for each set of seals, the seal at the lowest 
elevation shall have a corrosion resistant, non-metallic water drainage 
system. In addition, seals must not impound water or slurry, and water 
or slurry cannot be allowed to accumulate within the sealed area to any 
depth that can adversely affect a seal.
    This final rule revises the ETS requirement by allowing only non-
metallic materials to be used for a drainage system. This requirement 
is consistent with other provisions of this final rule regarding the 
removal of metallic objects through or across seals. MSHA experience 
shows that alternatives to metallic materials are readily available for 
use in drainage systems.
    In response to MSHA's request, several commenters stated that the 
ETS requirement that a seal not impound water is vague, that it is 
impossible to guarantee that there will be no water at a seal, and that 
there will always be some minimal amount of standing water in some 
mines. Seals should not be designed to impound water other than to a 
minimal depth, such as the height of the water trap. Based on MSHA's 
experience, drainage systems can be designed to prevent the 
accumulation and impoundment of mine water inby the seals. The actual 
size and number of pipes used in a drainage system should be based on 
the anticipated maximum flow rate at the seal location. In addition to 
being corrosion resistant and made of non-metallic material, drainage 
pipes must have strength properties consistent with the design strength 
of the seal, and the drainage system must have blast resistance 
equivalent to that of the seal. If the seal design does not allow any 
impoundment of water, the drainage system design could incorporate a 
water diversion or pumping system. For example, a low weir or catchment 
could be constructed across the entry inby the seal to trap sediment 
and debris that may impede drainage and prevent water from adversely 
affecting the seal. These provisions addressing water drainage systems 
and impoundment of water or

[[Page 21202]]

slurry accommodate varied mining conditions and assure safe and 
effective workplaces for miners.

D. Section 75.338 Training

    Final Sec.  75.338 addresses training for sampling and seal 
construction. This final rule consolidates the training requirements of 
ETS Sec. Sec.  75.335(b)(2) and 75.337(e) into this new section. The 
final rule changes the retention period for training certifications 
from one year to two years from the date of training. This change is 
made to be consistent with existing MSHA training standards at part 48. 
It provides that mine operators maintain training records under the 
final rule for the same period as existing training records. Consistent 
with the burden cost in MSHA's information collection package for part 
48, under OMB Control Number 1219-0009, the Agency determined that 
increasing the retention period from one year to two would not affect 
operator costs.
1. Section 75.338(a)
    Final Sec.  75.338(a), like the ETS, requires that certified 
persons conducting sampling be trained in the use of appropriate 
sampling equipment, procedures, location of sampling points, frequency 
of sampling, size and condition of the sealed area, and the use of 
continuous monitoring systems, if applicable, before they conduct 
sampling, and annually thereafter. The final rule also requires the 
mine operator to certify the date of training and retain each 
certification for two years, instead of one year under the ETS. This 
provision is similar to other certification requirements in 30 CFR part 
75.
2. Section 75.338(b)
    Final Sec.  75.338(b), like the ETS, requires the mine operator to 
provide training to miners constructing or repairing seals, designated 
certified persons, and designated senior mine management officials. 
This training must be conducted prior to constructing or repairing a 
seal and annually thereafter. The final rule also requires the mine 
operator to certify the date of training provided each miner, certified 
person, and senior mine management official, and retain each 
certification for two years.
    One commenter stated that the record showing certification of 
training for miners doing the construction of seals is required to be 
kept for only one year. If there is a seal failure outside of that time 
period, those records are no longer available during the investigation 
process. The commenter recommended that the certification be kept for 
as long as the seal is satisfying the purpose for which it was built.
    This final rule revises the ETS by requiring operators to retain 
training certifications for two years from the date of training. This 
change is consistent with existing Sec.  48.9 (records of training) 
which requires training certificates be kept at the mine site for two 
years. Training certifications need not be kept longer than two years 
because the final rule requires annual training for miners constructing 
or repairing seals. Annual training assures that miners are capable of 
repairing seals when necessary and therefore, the training 
certification would be up-to-date.
    Several commenters requested clarification as to whether the 
training provisions are included in part 48 training. Training required 
by the final rule should not be included in part 48 training, although 
the mine operator may choose to conduct the training at the same time. 
However, even though the ventilation plan review is required as part of 
the eight-hour annual refresher training, additional time must be 
allotted since the training is required by this section, not part 48.
    The final rule does not require a minimum amount of time for 
training. MSHA expects mine operators to determine the time necessary 
for this training based on the complexity of the seal design in the 
ventilation plan, construction or repair procedures, materials used, 
and knowledge and skill levels of persons receiving training. In 
addition, changes in the approved seal design or approved ventilation 
plan will necessitate that persons be retrained.

E. Section 75.339 Seals records

    Final Sec.  75.339, like ETS Sec.  75.338, addresses seals records.
1. Section 75.339(a)
    Final Sec.  75.339(a) lists the records a mine operator is required 
to maintain and the retention time for those records.
2. Section 75.339(b)
    Final Sec.  75.339(b), like the ETS, requires that records be 
retained at a surface location at the mine in a secure book that is not 
susceptible to alteration. The final rule allows records to be retained 
electronically in a computer system that is secure and not susceptible 
to alteration, if the mine operator can immediately access the record 
from the mine site.
    One commenter stated that after seal construction is completed and 
quality control test results have been provided to MSHA, the operator 
should be permitted to retain seal construction certification records 
at a central location. Because electronic storage of records is a 
practical and reliable method of records storage, the final rule allows 
records to be stored electronically, provided that the records are 
secure and not susceptible to alteration.
3. Section 75.339(c)
    Final Sec.  75.339(c) of the final rule remains unchanged from the 
ETS. It requires that, upon request from an authorized representative 
of the Secretary of Labor or Secretary of Health and Human Services, or 
from the authorized representative of miners, mine operators must 
promptly provide access to any record listed in the table in this 
section.
4. Section 75.339(d)
    Final Sec.  75.339(d), like the ETS, requires that whenever an 
operator ceases to do business, that operator must transfer all records 
required to be maintained by this part, or a copy thereof, to any 
successor operator who must maintain them for the required period. In 
addition, in response to comments, this final rule revises the ETS to 
require an operator who transfers control of the mine to another entity 
to transfer all records to that successor entity. Having access to 
records will allow MSHA and the new mine operator to determine if seals 
were designed, constructed, and repaired as approved and maintained to 
assure their reliability.

F. Section 75.371 Conforming Changes to Other Sections of Part 75

    Final Sec.  75.371(ff) requires the mine operator to provide in the 
ventilation plan the information provided in the sampling requirements 
in Sec.  75.336 and the seal installation requirements in Sec.  75.335. 
The sampling requirements in ETS Sec.  75.335(b) are revised and moved 
to final Sec.  75.336. The installation requirements provided by ETS 
Sec.  75.336(b)(3) are revised and moved to final Sec.  75.335. 
Therefore, this provision is revised to conform to the new section 
numbers.

IV. Executive Order 12866

    Executive Order (E.O.) 12866, as amended by E.O.13258 (Amending 
Executive Order 12866 on Regulatory Planning and Review), requires that 
regulatory agencies assess both the costs and benefits of regulations. 
To comply with E.O.12866, MSHA has prepared a Regulatory Economic 
Analysis (REA) for the final rule. The REA contains supporting data and 
explanation for the summary materials presented in this

[[Page 21203]]

preamble, including the covered mining industry, costs and benefits, 
feasibility, small business impacts, and paperwork. The REA is located 
on MSHA's Web site at http://www.msha.gov/REGSINFO.HTM. A copy of the 
REA can be obtained from MSHA's Office of Standards, Regulations, and 
Variances at the address in the ADDRESSES section of this preamble.
    Executive Order 12866 requires that regulatory agencies assess both 
the costs and benefits of significant regulatory actions. Under the 
Executive Order, a ``significant regulatory action'' is one meeting any 
of a number of specified conditions, including the following: Having an 
annual effect on the economy of $100 million or more, creating a 
serious inconsistency or interfering with an action of another, 
materially altering the budgetary impact of entitlements or the rights 
of entitlement recipients, or raising novel legal or policy issues. 
Based on the REA, MSHA has determined that the final rule does not have 
an annual effect of $100 million or more on the economy. Therefore, it 
is not an economically ``significant regulatory action'' under section 
3(f) of E.O. 12866. MSHA, however, has determined that the final rule 
is a ``significant action'' under Executive Order 12866 because it 
raises novel legal or policy issues.

A. Mine Sector Affected

    The final rule applies to all underground coal mines in the United 
States. Based on MSHA data as of February 5, 2008, there were 624 
underground coal mines, employing 42,207 miners, operating in the U.S. 
in 2007. Based on an MSHA survey conducted in November 2006, 372 
underground coal mines have seals. In 2007, these mines employed 32,412 
miners, of which 28,009 worked underground.

B. Benefits

    To provide a quantitative estimate of the benefits of this final 
rule, MSHA analyzed the explosions in sealed areas that have taken 
place since 1993 including the two accidents in 2006 where the seals 
failed and fatalities occurred. At the Sago Mine, 12 miners died, and 
at the Darby Mine, 5 miners died. If this final rule had been in 
effect, these lives might not have been lost.
    For purposes of estimating benefits for this final rule, MSHA 
attributes the potential saving of the 5 miners' lives from the Darby 
Mine accident to this final rule. MSHA also attributes the potential 
saving of half of the miners' lives from the Sago Mine accident. (MSHA 
attributes the remaining miners' lives from the Sago Mine accident to 
MSHA's 2006 emergency mine evacuation rule.) The total potential saving 
is 11 lives attributed to this final rule.
    One commenter stated that under the ETS, MSHA should not have 
included as a benefit potential lives saved from the Sago and Darby 
Mine accidents. This commenter stated that the design of the seals used 
at both the Sago and Darby Mines was not established as the cause of 
the deaths, that MSHA's accident reports focus on construction 
deficiencies of seals at both mines, and that the Darby Mine explosion 
resulted from miners attempting to cut a metal strap on the inby and 
outby side of a previously constructed seal. Based on MSHA's experience 
under the ETS, MSHA believes that the lives lost at the Sago and Darby 
Mine accidents might have been saved had this final rule been in 
effect. This final rule, like the ETS, addresses the design, 
construction, and maintenance of seals, and training of persons 
involved in seal construction and repair. The final rule requires 
insulated cables be removed from the area to be sealed, unless it is 
not safe to do so. In addition, this final rule does not permit 
welding, cutting, and soldering with an arc or flame within 150 feet of 
a seal unless such work is approved by the District Manager in the 
ventilation plan.
    MSHA has data on explosions that occurred in sealed areas. From 
1993 through 2006, there were 13 explosions in sealed areas. Of the 13 
explosions, 11 caused seal damage and had the potential to cause 
fatalities or injuries, and two caused fatalities or injuries. If the 
explosions followed approximately the same distribution as they did 
since 1993, MSHA estimates that this final rule would save 
approximately one life per year.
    Based on the Agency's knowledge and experience, MSHA determined 
that the risk from explosions in sealed areas was increasing from 1993 
through 2006 because the number of seals being installed was increasing 
during that period. After adjusting this estimate to account for the 
increased risk during the period, this final rule will save 
approximately 2 lives per year. The estimate that the final rule will 
save approximately 2 lives per year is based on an increased risk of an 
explosion during 1993-2006 because the number of seals in mines 
increased and the number of mines with seals increased. This is MSHA's 
best estimate of the number of lives saved per year due to the final 
rule.
    MSHA also developed a higher risk estimate based on the 
distribution of miners at risk and the characteristics of the 
explosions. If an explosion with the characteristics of the explosions 
at Sago or Darby Mines were to occur at a large mine, many lives 
potentially could be lost. Assuming that the risk of fatality from an 
explosion in a sealed area does not vary with the size of the mine, and 
that the number of potential fatalities is proportional to the number 
of miners working underground, MSHA estimates that approximately 6 
lives will be saved per year under this final rule.
    MSHA also calculated the cumulative risk over a 45-year working 
life of a miner. If, under MSHA's best estimate, this final rule saves 
approximately 2 lives per year, the risk of fatality from an explosion 
in a sealed area is approximately 3 per 1,000 miners over a 45-year 
working lifetime. If the final rule saves 6 lives per year under MSHA's 
higher estimate, the reduction in the lifetime risk of a fatality from 
an explosion in a sealed area is approximately 9 per 1,000 miners over 
a 45-year working lifetime.
    Under this final rule, an explosion is less likely to occur where 
the atmosphere behind seals is monitored and maintained inert. This 
final rule also requires stronger seals to better withstand explosions. 
The stronger seals will reduce miner injuries and fatalities should an 
explosion occur.

C. Compliance Costs

    MSHA estimates that the final rule will result in total yearly 
costs for underground coal mine operators of approximately $45.4 
million. Total first year costs are estimated to be approximately $46.4 
million. Disaggregated by mine size for mines that use seals, yearly 
costs are $2.8 million for the 83 mine operators with fewer than 20 
employees; $37.8 million for the 279 mine operators with 20-500 
employees; and $4.8 million for the 10 mine operators with more than 
500 employees. Most of the compliance costs occur in the mine size 
category with 20-500 employees because 75 percent of the mines that use 
seals are in this category.

V. Feasibility

    MSHA has concluded that the requirements of the final rule are 
technologically and economically feasible. For atmospheres behind seals 
where the atmosphere will not inert naturally, operators may choose any 
of the following alternatives for inerting the atmosphere: (1) 
Injecting inert gas; or (2) pressure balance of the ventilation system; 
or (3) injecting material into the strata surrounding the seals to 
reduce leakage. Other mines may choose to

[[Page 21204]]

construct new seals that are 120 psi or greater in front of all 
existing seals in the sealed area.

A. Technological Feasibility

    MSHA concludes that the final rule is technologically feasible. 
This conclusion is based on the requirements of the final rule for 
training, sampling, construction and repair. Compliance with these 
requirements is technologically feasible because the materials, 
equipment, and methods for implementing these requirements currently 
exist. In addition, this feasibility determination is supported by 
MSHA's approval of several seal designs at overpressures of 50 psi and 
120 psi.

B. Economic Feasibility

    The yearly compliance cost of the final rule is $45.4 million, 
which is 0.3 percent of all revenue for all underground coal mines. 
MSHA concludes that the final rule is economically feasible because the 
total yearly compliance cost is well below one percent of the estimated 
annual revenue for all underground coal mines.

VI. Regulatory Flexibility Act and Small Business Regulatory 
Enforcement Fairness Act

    Pursuant to the Regulatory Flexibility Act (RFA) of 1980, as 
amended by the Small Business Regulatory Enforcement Fairness Act 
(SBREFA), MSHA analyzed the impact of the final rule on small 
businesses. Based on that analysis, MSHA notified the Chief Counsel for 
Advocacy, Small Business Administration, and certified under the 
Regulatory Flexibility Act at 5 U.S.C. 605(b) that the final rule does 
not have a significant economic impact on a substantial number of small 
entities. The factual basis for this certification is in Chapter V of 
the REA, and is summarized below.

A. Definition of a Small Mine

    Under the RFA, in analyzing the impact of the final rule on small 
entities, MSHA must either use the Small Business Administration (SBA) 
definition for a small entity or, after consultation with the SBA 
Office of Advocacy, establish an alternative definition for the mining 
industry by publishing that definition in the Federal Register for 
notice and comment. MSHA uses the SBA definition. The SBA defines a 
small entity in the mining industry as an establishment with 500 or 
fewer employees. MSHA concludes that it can certify that the final rule 
does not have a significant economic impact on a substantial number of 
small entities, those mines with 500 or fewer employees.

B. Factual Basis for Certification

    MSHA initially evaluates the impacts on ``small entities'' by 
comparing the estimated compliance cost of a rule for small entities in 
the sector affected by the rule to the estimated revenue for the 
affected sector. When the estimated compliance cost is less than one 
percent of the estimated revenue, the Agency concludes that the rule 
does not have a significant economic impact on a substantial number of 
small entities. When the estimated compliance costs exceeds one percent 
of revenue, MSHA determines whether a further analysis is required.
    For underground coal mines, the estimated 2007 production was 
277,830,429 tons for mines that had 500 or fewer employees. Using a 
2007 price of underground coal of $40.37 per ton and total 2007 
underground coal production in tons, underground coal revenue is 
estimated to be approximately $11.2 billion for mines employing 500 or 
fewer employees. Thus, the yearly cost of the final rule for mines that 
have 500 or fewer employees is 0.36 percent of annual revenue. Using 
SBA's definition of a small mine (one having 500 or fewer employees), 
the yearly cost for underground coal mines to comply with the final 
rule is less than 1 percent of estimated annual revenue. Accordingly, 
MSHA has certified that the final rule does not have a significant 
impact on a substantial number of small entities.

VII. Paperwork Reduction Act of 1995

A. Summary

    The information collection requirements contained in the final rule 
are listed by the Office of Management and Budget (OMB) under control 
numbers 1219-0142 and 1219-0088.
    The final rule contains information collection requirements that 
MSHA estimates will result in 33,560 burden hours and approximately 
$2.36 million related burden costs to mine operators and seal 
manufacturers. This final rule contains information collection 
requirements in the following sections: Sec.  75.335 seal requirements, 
strengths, design applications, and installation; Sec.  75.336 sampling 
and monitoring requirements; Sec.  75.337 construction and repair of 
seals; and Sec.  75.338 training.
    A detailed explanation of the burden hours and related costs are in 
the Paperwork Reduction Act section of the Regulatory Economic Analysis 
(REA) for the final rule. The REA is located on MSHA's Web site at 
http://www.msha.gov/REGSINFO.HTM. A print copy of the REA can be 
obtained from MSHA's Office of Standards, Regulations, and Variances.

B. Details

    The information collection package has been submitted to the Office 
of Management and Budget (OMB) for review under 44 U.S.C. 3504(h) of 
the Paperwork Reduction Act of 1995, as amended. A copy of the 
information collection package can be obtained from the Department of 
Labor by e-mail request to [email protected] or by phone request at 
(202) 693-4129.
    The information collection package for the ETS, which also served 
as the proposal for this final rule, was approved by OMB under control 
numbers 1219-0142, for Sealing of Abandoned Areas; and 1219-0088, for 
Ventilation Plans, Tests, and Examinations in Underground Coal Mines. 
MSHA estimated that the information collection requirements in the ETS 
would result in 82,037 annual burden hours and approximately $4.7 
million in related annual burden costs. MSHA has reduced these 
estimates in the final rule to 33,553 annual burden hours and 
approximately $2.36 million related annual burden costs. MSHA's 
estimated reduction in burden hours is due to: (1) The removal of 
approximately 41,600 hours of sampling time that was inadvertently 
included with recordkeeping time and counted as paperwork; (2) the 
removal of approximately 900 hours of time to prepare for training that 
was inadvertently included as paperwork; (3) the removal of 
approximately 3,000 hours of paperwork associated with the deleted 
requirement for a sampling protocol and action plan; and (4) 
approximately 3,000 hours of paperwork due to various other changes in 
the final rule.
    Several commenters raised concerns regarding the ETS requirement 
that multiple persons must certify that seal construction was done 
correctly. These comments are addressed in earlier sections of this 
preamble.

VIII. Other Regulatory Considerations

A. The Unfunded Mandates Reform Act of 1995

    MSHA has reviewed the final rule under the Unfunded Mandates Reform 
Act of 1995 (2 U.S.C. 1501 et seq). MSHA has determined that the final 
rule does not include any federal mandate that may result in increased 
expenditures by State, local, or tribal governments; nor will it 
increase private sector expenditures by more than $100

[[Page 21205]]

million in any one year or significantly or uniquely affect small 
governments. Accordingly, the Unfunded Mandates Reform Act of 1995 (2 
U.S.C. 1501 et seq) requires no further agency action or analysis.

B. The Treasury and General Government Appropriations Act of 1999: 
Assessment of Federal Regulations and Policies on Families

    Section 654 of the Treasury and General Government Appropriations 
Act of 1999 (5 U.S.C. 601 note) requires agencies to assess the impact 
of Agency action on family well-being. MSHA has determined that the 
final rule has no effect on family stability or safety, marital 
commitment, parental rights and authority, or income or poverty of 
families and children. Accordingly, MSHA certifies that the final rule 
does not impact family well-being.

C. Executive Order 12630: Government Actions and Interference With 
Constitutionally Protected Property Rights

    The final rule does not implement a policy with takings 
implications. Accordingly, under E.O. 12630, no further Agency action 
or analysis is required.

D. Executive Order 12988: Civil Justice Reform

    The final rule was written to provide a clear legal standard for 
affected conduct and was carefully reviewed to eliminate drafting 
errors and ambiguities, so as to minimize litigation and undue burden 
on the Federal court system. Accordingly, the final rule meets the 
applicable standards provided in section 3 of E.O. 12988, Civil Justice 
Reform.

E. Executive Order 13045: Protection of Children From Environmental 
Health Risks and Safety Risks

    The final rule has no adverse impact on children. Accordingly, 
under E.O. 13045, no further Agency action or analysis is required.

F. Executive Order 13132: Federalism

    The final rule does not have ``federalism implications'' because it 
does not ``have substantial direct effects on the States, on the 
relationship between the national government and the States, or on the 
distribution of power and responsibilities among the various levels of 
government.'' Accordingly, under E.O. 13132, no further Agency action 
or analysis is required.

G. Executive Order 13175: Consultation and Coordination With Indian 
Tribal Governments

    The final rule does not have ``tribal implications'' because it 
will not ``have substantial direct effects on one or more Indian 
tribes, on the relationship between the Federal government and Indian 
tribes, or on the distribution of power and responsibilities between 
the Federal government and Indian tribes.'' Accordingly, under E.O. 
13175, no further Agency action or analysis is required.

H. Executive Order 13211: Actions Concerning Regulations That 
Significantly Affect Energy Supply, Distribution, or Use

    Executive Order 13211 requires agencies to publish a statement of 
energy effects when a rule has a significant energy action that 
adversely affects energy supply, distribution or use. MSHA has reviewed 
the final rule for its energy effects because the final rule applies to 
the underground mining sector. Because this final rule will result in 
yearly costs of approximately $45.4 million to the underground coal 
mining industry, relative to annual revenues of $14.1 billion in 2007, 
MSHA has concluded that it is not a significant energy action because 
it is not likely to have a significant adverse effect on the supply, 
distribution, or use of energy. Accordingly, under this analysis, no 
further Agency action or analysis is required.

I. Executive Order 13272: Proper Consideration of Small Entities in 
Agency Rulemaking

    MSHA has thoroughly reviewed the final rule to assess and take 
appropriate account of its potential impact on small businesses, small 
governmental jurisdictions, and small organizations. MSHA has 
determined and certified that the final rule will not have a 
significant economic impact on a substantial number of small entities.

IX. References

ACI 318-05, ``Building Code Requirements for Structural Concrete and 
Commentary,'' American Concrete Institute.
ACI 440.2R-02, ``Design and Construction of Externally Bonded FRP 
Systems for Strengthening Concrete Structures,'' American Concrete 
Institute.
Army TM 5-1300, Navy NAVFAC P0397, Air Force AFR 88-22, Departments 
of the Army, the Navy, and the Air Force, ``Structures to Resist the 
Effects of Accidental Explosions,'' November 1990.
ASTM E119-07, ``Standard Test Methods for Fire Tests of Building 
Construction and Materials,'' ASTM International.
ASTM E162-06, ``Surface Flammability of Materials Using a Radiant 
Heat Energy Source,'' ASTM International.
Coward, H.F. and G.W. Jones, ``Limits of Flammability of Gases and 
Vapors,'' Bulletin 503, U.S. Dept. of the Interior, Bureau of Mines, 
1952.
Department of Labor, Mine Safety and Health Administration, Final 
Rule, Underground Coal Mine Ventilation Standards, May 15, 1992.
Kissell, Fred N., ``Handbook for Methane Control in Mining,'' 
Information Circular 9486. National Institute of Occupational Safety 
and Health, U.S. Dept. of Health and Human Services, 2006.
Mitchell, Donald W., ``Explosion-Proof Bulkheads--Present 
Practices,'' Report of Investigations No. 7581, U.S. Dept. of the 
Interior, Bureau of Mines, 1971.
Mitchell, Donald W., Burns, Frank A., ``Interpreting the State of a 
Mine Fire,'' Investigational Report No. 1103, U.S. Department of 
Labor, Mine Safety and Health Administration, 1979.
MSHA. Report of Investigation/Mine Explosion, Sago Mine, January 2, 
2006.
MSHA. Report of Investigation/Mine Explosion, Darby Mine No. 1, May 
20, 2006.
MSHA. Program Information Bulletin No. P06-11, ``Moratorium on 
Future Use of Alternative Seal Methods and Materials Pursuant to 30 
CFR 75.335 and Assessment of Existing Sealed Areas in Underground 
Bituminous Coal Mines,'' June 1, 2006.
MSHA. Program Information Bulletin No. P06-12, ``Reissued Moratorium 
on Future Use of Alternative Seal Methods and Materials Pursuant to 
30 CFR 75.335 and Assessment of Existing Sealed Areas in Underground 
Bituminous Coal Mines,'' June 12, 2006.
MSHA. Program Information Bulletin No. P06-14, ``Reissued Moratorium 
on Future Use of Alternative Seal Methods and Materials Pursuant to 
30 CFR 75.335 and Assessment of Existing Sealed Areas in Underground 
Bituminous Coal Mines,'' June 21, 2006.
MSHA. Program Information Bulletin No. P06-16, ``Use of Alternative 
Seal Methods and Materials Pursuant to 30 CFR 75.335(a)(2),'' July 
19, 2006.
MSHA. Procedure Instruction Letter No. I06-V-9, ``Procedures for 
Approval of Alternative Seals,'' August 21, 2006.
MSHA. Program Policy Manual, Volume V--Coal Mines, Release V-33, 
February 2003.
MSHA, Approval and Certification Center, Application Cancellation 
Policy, CDS No. APOL1009, Revised February 27, 2004.
Zipf, R. K., Sapko, M. J., Brune, J. F., ``Explosion Pressure Design 
Criteria for New Seals in U.S. Coal Mines, Draft Report,'' National 
Institute of Occupational Safety and Health, U.S. Dept. of Health 
and Human Services, February 8, 2007.
Zipf, R. K., Sapko, M. J., Brune, J. F., Information Circular-9500, 
``Explosion Pressure Design Criteria for New Seals in U.S. Coal 
Mines,'' National Institute of Occupational Safety and Health, U.S. 
Dept. of Health and Human Services, July 2007.

[[Page 21206]]

List of Subjects in 30 CFR Part 75

    Mine safety and health, Reporting and recordkeeping requirements, 
Underground coal mines, Ventilation.

    Dated: April 14, 2008.
Richard E. Stickler,
Acting Assistant Secretary for Mine Safety and Health.


0
Chapter I of Title 30, part 75 of the Code of Federal Regulations is 
amended as follows:

PART 75--MANDATORY SAFETY STANDARDS--UNDERGROUND COAL MINES

0
1. The authority citation for part 75 continues to read as follows:

    Authority: 30 U.S.C. 811.


0
2. Revise Sec.  75.335 to read as follows:


Sec.  75.335  Seal strengths, design applications, and installation.

    (a) Seal strengths. Seals constructed on or after October 20, 2008 
shall be designed, constructed, and maintained to withstand--
    (1)(i) At least 50-psi overpressure when the atmosphere in the 
sealed area is monitored and maintained inert and designed using a 
pressure-time curve with an instantaneous overpressure of at least 50 
psi. A minimum overpressure of at least 50 psi shall be maintained for 
at least four seconds then released instantaneously.
    (ii) Seals constructed to separate the active longwall panel from 
the longwall panel previously mined shall be designed using a pressure-
time curve with a rate of pressure rise of at least 50 psi in 0.1 
second. A minimum overpressure of at least 50 psi shall be maintained; 
or
    (2)(i) Overpressures of at least 120 psi if the atmosphere in the 
sealed area is not monitored, is not maintained inert, the conditions 
in paragraphs (a)(3)(i) through (iii) of this section are not present, 
and the seal is designed using a pressure-time curve with an 
instantaneous overpressure of at least 120 psi. A minimum overpressure 
of 120 psi shall be maintained for at least four seconds then released 
instantaneously.
    (ii) Seals constructed to separate the active longwall panel from 
the longwall panel previously mined shall be designed using a pressure-
time curve with a rate of pressure rise of 120 psi in 0.25 second. A 
minimum overpressure of 120 psi shall be maintained; or
    (3) Overpressures greater than 120 psi if the atmosphere in the 
sealed area is not monitored and is not maintained inert, and
    (i) The atmosphere in the sealed area is likely to contain 
homogeneous mixtures of methane between 4.5 percent and 17.0 percent 
and oxygen exceeding 17.0 percent throughout the entire area;
    (ii) Pressure piling could result in overpressures greater than 120 
psi in the area to be sealed; or
    (iii) Other conditions are encountered, such as the likelihood of a 
detonation in the area to be sealed.
    (iv) Where the conditions in paragraphs (a)(3)(i), (ii), or (iii) 
of this section are encountered, the mine operator shall revise the 
ventilation plan to address the potential hazards. The plan shall 
include seal strengths sufficient to address such conditions.
    (b) Seal design applications. Seal design applications from seal 
manufacturers or mine operators shall be in accordance with paragraphs 
(b)(1) or (b)(2) of this section and submitted for approval to MSHA's 
Office of Technical Support, Pittsburgh Safety and Health Technology 
Center, P.O. Box 18233, Cochrans Mill Road, Pittsburgh, PA 15236.
    (1) An engineering design application shall--
    (i) Address gas sampling pipes, water drainage systems, methods to 
reduce air leakage, pressure-time curve, fire resistance 
characteristics, flame spread index, entry size, engineering design and 
analysis, elasticity of design, material properties, construction 
specifications, quality control, design references, and other 
information related to seal construction;
    (ii) Be certified by a professional engineer that the design of the 
seal is in accordance with current, prudent engineering practices and 
is applicable to conditions in an underground coal mine; and
    (iii) Include a summary of the installation procedures related to 
seal construction; or
    (2) Each application based on full-scale explosion tests or 
equivalent means of physical testing shall address the following 
requirements to ensure that a seal can reliably meet the seal strength 
requirements:
    (i) Certification by a professional engineer that the testing was 
done in accordance with current, prudent engineering practices for 
construction in a coal mine;
    (ii) Technical information related to the methods and materials;
    (iii) Supporting documentation;
    (iv) An engineering analysis to address differences between the 
seal support during test conditions and the range of conditions in a 
coal mine; and
    (v) A summary of the installation procedures related to seal 
construction.
    (3) MSHA will notify the applicant if additional information or 
testing is required. The applicant shall provide this information, 
arrange any additional or repeat tests, and provide prior notification 
to MSHA of the location, date, and time of such test(s).
    (4) MSHA will notify the applicant, in writing, whether the design 
is approved or denied. If the design is denied, MSHA will specify, in 
writing, the deficiencies of the application, or necessary revisions.
    (5) Once the seal design is approved, the approval holder shall 
promptly notify MSHA, in writing, of all deficiencies of which they 
become aware.
    (c) Seal installation approval. The installation of the approved 
seal design shall be subject to approval in the ventilation plan. The 
mine operator shall--
    (1) Retain the seal design approval and installation information 
for as long as the seal is needed to serve the purpose for which it was 
built.
    (2) Designate a professional engineer to conduct or have oversight 
of seal installation and certify that the provisions in the approved 
seal design specified in this section have been addressed and are 
applicable to conditions at the mine. A copy of the certification shall 
be submitted to the District Manager with the information provided in 
paragraph (c)(3) of this section and a copy of the certification shall 
be retained for as long as the seal is needed to serve the purpose for 
which it was built.
    (3) Provide the following information for approval in the 
ventilation plan--
    (i) The MSHA Technical Support Approval Number;
    (ii) A summary of the installation procedures;
    (iii) The mine map of the area to be sealed and proposed seal 
locations that include the deepest points of penetration prior to 
sealing. The mine map shall be certified by a professional engineer or 
a professional land surveyor.
    (iv) Specific mine site information, including--
    (A) Type of seal;
    (B) Safety precautions taken prior to seal achieving design 
strength;
    (C) Methods to address site-specific conditions that may affect the 
strength and applicability of the seal including set-back distances;
    (D) Site preparation;
    (E) Sequence of seal installations;
    (F) Projected date of completion of each set of seals;

[[Page 21207]]

    (G) Supplemental roof support inby and outby each seal;
    (H) Water flow estimation and dimensions of the water drainage 
system through the seals;
    (I) Methods to ventilate the outby face of seals once completed;
    (J) Methods and materials used to maintain each type of seal;
    (K) Methods to address shafts and boreholes in the sealed area;
    (L) Assessment of potential for overpressures greater than 120 psi 
in sealed area;
    (M) Additional sampling locations; and
    (N) Additional information required by the District Manager.

0
3. Revise Sec.  75.336 to read as follows:


Sec.  75.336  Sampling and monitoring requirements.

    (a) A certified person as defined in Sec.  75.100 shall monitor 
atmospheres of sealed areas. Sealed areas shall be monitored, whether 
ingassing or outgassing, for methane and oxygen concentrations and the 
direction of leakage.
    (1) Each sampling pipe and approved sampling location shall be 
sampled at least every 24 hours.
    (i) Atmospheres with seals of 120 psi or greater shall be sampled 
until the design strength is reached for every seal used to seal the 
area.
    (ii) Atmospheres with seals less than 120 psi constructed before 
October 20, 2008 shall be monitored for methane and oxygen 
concentrations and maintained inert. The operator may request that the 
District Manager approve different sampling locations and frequencies 
in the ventilation plan, provided at least one sample is taken at each 
set of seals at least every 7 days.
    (iii) Atmospheres with seals less than 120 psi constructed after 
October 20, 2008 shall be monitored for methane and oxygen 
concentrations and maintained inert. The operator may request that the 
District Manager approve different sampling locations and frequencies 
in the ventilation plan after a minimum of 14 days and after the seal 
design strength is reached, provided at least one sample is taken at 
each set of seals at least every 7 days.
    (2) The mine operator shall evaluate the atmosphere in the sealed 
area to determine whether sampling through the sampling pipes in seals 
and approved locations provides appropriate sampling locations of the 
sealed area. The mine operator shall make the evaluation immediately 
after the minimum 14-day required sampling, if the mine ventilation 
system is reconfigured, if changes occur that adversely affect the 
sealed area, or if the District Manager requests an evaluation. When 
the results of the evaluations indicate the need for additional 
sampling locations, the mine operator shall provide the additional 
locations and have them approved in the ventilation plan. The District 
Manager may require additional sampling locations and frequencies in 
the ventilation plan.
    (3) Mine operators with an approved ventilation plan addressing 
spontaneous combustion pursuant to Sec.  75.334(f) shall sample the 
sealed atmosphere in accordance with the ventilation plan.
    (4) The District Manager may approve in the ventilation plan the 
use of a continuous monitoring system in lieu of monitoring provisions 
in this section.
    (b)(1) Except as provided in Sec.  75.335(d), the atmosphere in the 
sealed area is considered inert when the oxygen concentration is less 
than 10.0 percent or the methane concentration is less than 3.0 percent 
or greater than 20.0 percent.
    (2) Immediate action shall be taken by the mine operator to restore 
an inert sealed atmosphere behind seals with strengths less than 120 
psi. Until the atmosphere in the sealed area is restored to an inert 
condition, the sealed atmosphere shall be monitored at each sampling 
pipe and approved location at least once every 24 hours.
    (c) Except as provided in Sec.  75.335(d), when a sample is taken 
from the sealed atmosphere with seals of less than 120 psi and the 
sample indicates that the oxygen concentration is 10 percent or greater 
and methane is between 4.5 percent and 17 percent, the mine operator 
shall immediately take an additional sample and then immediately notify 
the District Manager. When the additional sample indicates that the 
oxygen concentration is 10 percent or greater and methane is between 
4.5 percent and 17 percent, persons shall be withdrawn from the 
affected area which is the entire mine or other affected area 
identified by the operator and approved by the District Manager in the 
ventilation plan, except those persons referred to in Sec.  104(c) of 
the Act. The operator may identify areas in the ventilation plan to be 
approved by the District Manager where persons may be exempted from 
withdrawal. The operator's request shall address the location of seals 
in relation to: Areas where persons work and travel in the mine; 
escapeways and potential for damage to the escapeways; and ventilation 
systems and controls in areas where persons work or travel and where 
ventilation is used for escapeways. The operator's request shall also 
address the gas concentration of other sampling locations in the sealed 
area and other required information. Before miners reenter the mine, 
the mine operator shall have a ventilation plan revision approved by 
the District Manager specifying the actions to be taken.
    (d) In sealed areas with a demonstrated history of carbon dioxide 
or sealed areas where inert gases have been injected, the operator may 
request that the District Manager approve in the ventilation plan an 
alternative method to determine if the sealed atmosphere is inert and 
when miners have to be withdrawn. The mine operator shall address in 
the ventilation plan the specific levels of methane, carbon dioxide, 
nitrogen and oxygen; the sampling methods and equipment used; and the 
methods to evaluate these concentrations underground at the seal.
    (e) Recordkeeping. (1) The certified person shall promptly record 
each sampling result including the location of the sampling points, 
whether ingassing or outgassing, and oxygen and methane concentrations. 
The results of oxygen and methane samples shall be recorded as the 
percentage of oxygen and methane measured by the certified person and 
any hazardous condition found in accordance with Sec.  75.363.
    (2) The mine operator shall retain sampling records at the mine for 
at least one year from the date of the sampling.

0
4. Revise Sec.  75.337 to read as follows:


Sec.  75.337  Construction and repair of seals.

    (a) The mine operator shall maintain and repair seals to protect 
miners from hazards of sealed areas.
    (b) Prior to sealing, the mine operator shall--
    (1) Remove insulated cables, batteries, and other potential 
electric ignition sources from the area to be sealed when constructing 
seals, unless it is not safe to do so. If ignition sources cannot 
safely be removed, seals must be constructed to at least 120 psi;
    (2) Remove metallic objects through or across seals; and
    (3) Breach or remove all stoppings in the first crosscut inby the 
seals immediately prior to sealing the area.
    (c) A certified person designated by the mine operator shall 
directly supervise seal construction and repair and--
    (1) Examine each seal site immediately prior to construction or 
repair to ensure that the site is in accordance with the approved 
ventilation plan;
    (2) Examine each seal under construction or repair during each 
shift to ensure that the seal is being

[[Page 21208]]

constructed or repaired in accordance with the approved ventilation 
plan;
    (3) Examine each seal upon completion of construction or repair to 
ensure that construction or repair is in accordance with the approved 
ventilation plan;
    (4) Certify by initials, date, and time that the examinations were 
made; and
    (5) Make a record of the examination at the completion of any shift 
during which an examination was conducted. The record shall include 
each deficiency and the corrective action taken. The record shall 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. The record shall be kept at the mine for one 
year.
    (d) Upon completion of construction of each seal a senior mine 
management official, such as a mine manager or superintendent, shall 
certify that the construction, installation, and materials used were in 
accordance with the approved ventilation plan. The mine operator shall 
retain the certification for as long as the seal is needed to serve the 
purpose for which it was built.
    (e) The mine operator shall--
    (1) Notify the District Manager between two and fourteen days prior 
to commencement of seal construction;
    (2) Notify the District Manager, in writing, within five days of 
completion of a set of seals and provide a copy of the certification 
required in paragraph (d) of this section; and
    (3) Submit a copy of quality control results to the District 
Manager for seal material properties specified by Sec.  75.335 within 
30 days of completion of quality control tests.
    (f) Welding, cutting, and soldering. Welding, cutting, and 
soldering with an arc or flame are prohibited within 150 feet of a 
seal. An operator may request a different location in the ventilation 
plan to be approved by the District Manager. The operator's request 
must address methods the mine operator will use to continuously monitor 
atmospheric conditions in the sealed area during welding or burning; 
the airflow conditions in and around the work area; the rock dust and 
water application methods; the availability of fire extinguishers on 
hand; the procedures to maintain safe conditions, and other relevant 
factors.
    (g) Sampling pipes. (1) For seals constructed after April 18, 2008, 
one non-metallic sampling pipe shall be installed in each seal that 
shall extend into the center of the first connecting crosscut inby the 
seal. If an open crosscut does not exist, the sampling pipe shall 
extend one-half of the distance of the open entry inby the seal.
    (2) Each sampling pipe shall be equipped with a shut-off valve and 
appropriate fittings for taking gas samples.
    (3) The sampling pipes shall be labeled to indicate the location of 
the sampling point when more than one sampling pipe is installed 
through a seal.
    (4) If a new seal is constructed to replace or reinforce an 
existing seal with a sampling pipe, the sampling pipe in the existing 
seal shall extend through the new seal. An additional sampling pipe 
shall be installed through each new seal to sample the area between 
seals, as specified in the approved ventilation plan.
    (h) Water drainage system. For each set of seals constructed after 
April 18, 2008, the seal at the lowest elevation shall have a 
corrosion-resistant, non-metallic water drainage system. Seals shall 
not impound water or slurry. Water or slurry shall not accumulate 
within the sealed area to any depth that can adversely affect a seal.

0
5. Revise Sec.  75.338 to read as follows:


Sec.  75.338  Training.

    (a) Certified persons conducting sampling shall be trained in the 
use of appropriate sampling equipment, procedures, location of sampling 
points, frequency of sampling, size and condition of the sealed area, 
and the use of continuous monitoring systems if applicable before they 
conduct sampling, and annually thereafter. The mine operator shall 
certify the date of training provided to certified persons and retain 
each certification for two years.
    (b) Miners constructing or repairing seals, designated certified 
persons, and senior mine management officials shall be trained prior to 
constructing or repairing a seal and annually thereafter. The training 
shall address materials and procedures in the approved seal design and 
ventilation plan. The mine operator shall certify the date of training 
provided each miner, certified person, and senior mine management 
official and retain each certification for two years.

0
6. Add Sec.  75.339 to read as follows:


Sec.  75.339  Seals records.

    (a) The table entitled ``Seal Recordkeeping Requirements'' lists 
records the operator shall maintain and the retention period for each 
record.

         Table--Sec.   75.339(a) Seal Recordkeeping Requirements
------------------------------------------------------------------------
            Record              Section reference      Retention time
------------------------------------------------------------------------
(1) Approved seal design......  75.335(c)(1).....  As long as the seal
                                                    is needed to serve
                                                    the purpose for
                                                    which it is built.
(2) Certification of            75.335(c)(2).....  As long as the seal
 Provisions of Approved Seal                        is needed to serve
 Design is Addressed.                               the purpose for
                                                    which it is built.
(3) Gas sampling records......  75.336(e)(2).....  1 year.
(4) Record of examinations....  75.337(c)(5).....  1 year.
(5) Certification of seal       75.337(d)........  As long as the seal
 construction, installation,                        is needed to serve
 and materials.                                     the purpose for
                                                    which it is built.
(6) Certification of Training   75.338(a)........  2 years.
 for Persons that Sample.
(7) Certification of Training   75.338(b)........  2 years.
 for Persons that Perform Seal
 Construction and Repair.
------------------------------------------------------------------------

    (b) Records required by Sec. Sec.  75.335, 75.336, 75.337 and 
75.338 shall be retained at a surface location at the mine in a secure 
book that is not susceptible to alteration. The records may be retained 
electronically in a computer system that is secure and not susceptible 
to alteration, if the mine operator can immediately access the record 
from the mine site.
    (c) Upon request from an authorized representative of the Secretary 
of Labor, the Secretary of Health and Human Services, or from the 
authorized representative of miners, mine operators shall promptly 
provide access to any record listed in the table in this section.

[[Page 21209]]

    (d) Whenever an operator ceases to do business or transfers control 
of the mine to another entity, that operator shall transfer all records 
required to be maintained by this part, or a copy thereof, to any 
successor operator who shall maintain them for the required period.

0
7. Amend Sec.  75.371 by revising paragraph (ff) to read as follows:


Sec.  75.371  Mine ventilation plan; contents.

* * * * *
    (ff) Seal installation requirements provided by Sec.  75.335 and 
the sampling provisions provided by Sec.  75.336.
* * * * *
[FR Doc. 08-1152 Filed 4-16-08; 2:14 pm]
BILLING CODE 4510-43-P