[Federal Register Volume 68, Number 44 (Thursday, March 6, 2003)]
[Proposed Rules]
[Pages 10784-10884]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 03-3941]



[[Page 10783]]

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Part II





Department of Labor





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Mine Safety and Health Administration



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30 CFR Parts 70, 75, and 90



Verification of Underground Coal Mine Operators' Dust Control Plans and 
Compliance Sampling for Respirable Dust; Proposed Rule

  Federal Register / Vol. 68, No. 44 / Thursday, March 6, 2003 / 
Proposed Rules  

[[Page 10784]]


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DEPARTMENT OF LABOR

Mine Safety and Health Administration

30 CFR Parts 70, 75 and 90

RIN 1219-AB14


Verification of Underground Coal Mine Operators' Dust Control 
Plans and Compliance Sampling for Respirable Dust

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

ACTION: Proposed rule; notice of public hearings; close of record.

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SUMMARY: This proposed rule supercedes the proposed rule published by 
MSHA on July 7, 2000. Under this proposed rule mine operators would be 
required to verify and periodically monitor, through sampling, the 
effectiveness of the dust control parameters for each mechanized mining 
unit (MMU) specified in the mine ventilation plan. For samples to be 
valid, the operator would be required to sample on a production shift 
during which the amount of material produced by a MMU is at or above 
the verification production level using only the dust control 
parameters listed in the ventilation plan. The use of approved powered, 
air-purifying respirators (PAPRs) and/or verifiable administrative 
controls would be allowed as a supplemental means of compliance when 
MSHA determines that all feasible engineering or environmental controls 
are being used. MSHA is also proposing to rescind operator compliance 
sampling in underground coal mines. The use of a personal, continuous 
dust monitor (PCDM), once developed and approved, could be used by an 
operator in conjunction with the dust control parameters specified in 
the mine ventilation plan. The proposed rule would significantly 
improve miners health protection by limiting the exposure of individual 
miners to respirable coal mine dust.

DATES: Comments on the proposed rule should be submitted on or before 
June 4, 2003.
    MSHA also is announcing that the Agency will hold public hearings 
on the proposed rule. The hearing dates and times will be announced by 
a separate document in the Federal Register.

ADDRESSES: Comments must be clearly identified as such and transmitted 
either electronically to [email protected], by facsimile to (202) 693-
9441, or by regular mail or hand delivery to MSHA, Office of Standards, 
Regulations, and Variances, 1100 Wilson Blvd., Room 2313, Arlington, 
Virginia 22209-3939. You may contact MSHA with any format questions. 
Comments are posted for public viewing at http://www.msha.gov/currentcomments.htm.

Information Collection Requirements

    Send written comments on the information collection requirements to 
both the Office of Management and Budget (OMB) and MSHA as follows:
    (1) To OMB: If under 10 pages, by facsimile (202) 395-6974 to Attn: 
Desk Officer for MSHA; or by email to: [email protected]. All comments 
may be sent by mail addressed to the Office of Information and 
Regulatory Affairs, Office of Management and Budget, New Executive 
Office Building, 725 17th Street, NW., Washington, DC 20503, Attn: Desk 
Officer for MSHA; and
    (2) To MSHA: Comments must be clearly identified as comments on the 
information collection requirements and transmitted either 
electronically to [email protected], by facsimile to (202) 693-9441, or 
by regular mail or hand delivery to MSHA, Office of Standards, 
Regulations, and Variances, 1100 Wilson Blvd., Room 2313, Arlington, 
Virginia 22209-3939.

FOR FURTHER INFORMATION CONTACT: Marvin W. Nichols, Jr., Director, 
Office of Standards, Regulations and Variances, MSHA; phone: (202) 693-
9440; facsimile: (202) 693-9441; E-mail: [email protected].
    This proposed rule is also available on MSHA's webpage at http://www.msha.gov, under Statutory and Regulatory Information; Federal 
Register Documents; Proposed Rules. You can view comments filed on this 
rulemaking at http://www.msha.gov/currentcomments.htm.

SUPPLEMENTARY INFORMATION:

I. Table of Contents
II. Background
    A. Procedural History
    B. Overview of Proposed Rule
    1. New Proposed Respirable Dust Sampling Program
    2. Verification of Ventilation Plan Effectiveness
    3. Measures to Supplement Engineering Controls to Reduce 
Exposures
    C. Control of Coal Mine Respirable Dust
    D. Coal Mine Respirable Dust Task Group
    E. NIOSH Criteria Document
    F. Advisory Committee on the Elimination of Pneumoconiosis Among 
Coal Mine Workers
III. General Discussion
    A. Proposed Reforms to the Respirable Dust Monitoring Program
    a. Compliance Sampling
    b. Abatement Sampling
    c. Operator Verification Sampling and Quarterly Sampling
    d. Advantages of MSHA Sampling Over the Existing Program
    B. Procedures for Setting the Applicable Dust Standard When 
Quartz is Present
    1. Proposed Procedures
    2. Validity of Averaging Percentages
    C. Respirable Dust Control Program for Underground Coal Mines
    1. Proposed Procedures for Evaluating, Approving, and Monitoring 
Plan Requirements
    D. Hierarchy of Dust Controls
    1. Primacy of Engineering Controls
    2. Administrative Controls
    3. Limitations of Engineering Controls
    4. Respiratory Protection
    a. Selection of Respirators: Powered Air-Purifying Respirators 
(PAPR)
    b. PAPR Protection Program
    c. PAPR Protection Factor
    E. Guidelines for Determining What is a Feasible Dust Control
    F. Application of New Technology for Monitoring Coal Mine Dust 
Levels
IV. Section-by-Section Discussion of Proposed Rule
    A. Part 70
    B. Part 75
    C. Part 90
V. Health Effects
    A. Introduction
    B. Hazard Identification
    1. Agent: Coal
    2. Physical State: Coal Mine Dust
    3. Biological Action: Respirable Coal Mine Dust
    C. Health Effects of Respirable Coal Mine Dust
    1. Description of Major Health Effects
    a. Simple Coal Workers' Pneumoconiosis (Simple CWP) and 
Progressive Massive Fibrosis (PMF)
    b. Other Health Effects
    2. Toxicological Literature
    3. Epidemiological Literature
    a. Simple Coal Workers' Pneumoconiosis (Simple CWP) and 
Progressive Massive Fibrosis (PMF)
    b. Other Health Effects
VI. Quantitative Risk Assessment
VII. Significance of Risk
VIII. Feasibility Issues
    A. Technological Feasibility
    B. Economic Feasibility
IX. Preliminary Regulatory Economic Analysis
    A. Costs and Benefits: Executive Order 12866
    1. Compliance Costs
    2. Benefits
    B. Regulatory Flexibility Certification and Regulatory 
Flexibility Analysis
X. Other Statutory Requirements
    A. Unfunded Mandates Reform Act of 1995
    B. Paperwork Reduction Act of 1995
    C. National Environmental Policy Act
    D. Executive Order 12630: Governmental Actions and Interference 
with Constitutionally Protected Property Rights
    E. Executive Order 12988: Civil Justice Reform
    F. Executive Order 13045: Protection of Children from 
Environmental Health Risks and Safety Risks
    G. Executive Order 13175: Consultation and Coordination with 
Indian Tribal Governments

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    H. Executive Order 13132: Federalism
    I. Executive Order 13211: Energy
    J. Executive Order 13272: Proper Consideration of Small Entities 
in Agency Rulemaking
XI. Public Hearings
    Appendix A. Derivation of the Critical Values
    Appendix B. Model Powered Air-Purifying Respirator (PAPR) 
Program
    Appendix C. Citation Threshold Values (CTV)
    Appendix D. References
    Appendix E. Supplemental References
XII. Regulatory Text

II. Background

A. Procedural History

    On July 7, 2000, the Mine Safety and Health Administration 
published a Notice of Proposed Rulemaking (NPRM) in the Federal 
Register: Verification of Underground Coal Mine Operators' Dust Control 
Plans and Compliance Sampling for Respirable Dust (65 FR 42122). A 
notice of public hearing and close of record was also published in the 
Federal Register (65 FR 42186) on July 7, 2000. During August 2000, 
three public hearings were conducted in Morgantown, West Virginia; 
Prestonsburg, Kentucky; and Salt Lake City, Utah. Transcripts of those 
proceedings were made available to the public. The close of the 
rulemaking record was originally scheduled for August 24, 2000. In 
response to requests from commenters, an extension of the comment 
period for the NPRM was published in the Federal Register (65 FR 49215) 
on August 11, 2000; the rulemaking comment period was extended to 
September 8, 2000. Supplementary statements and data postmarked on or 
before the close of the record, September 8, 2000, were included in the 
rulemaking record and made available to the public.
    Many commenters on the proposed rule urged MSHA to withdraw the 
proposed rule and publish another. In their opinion, the agency failed 
to adequately address the concerns of mine operators and ignored other 
reforms in the dust sampling program urged by coal miners since the mid 
1970s or that were recommended by the Secretary of Labor's Advisory 
Committee on the Elimination of Pneumoconiosis Among Coal Workers (Dust 
Advisory Committee) and the NIOSH Criteria Document addressing 
respirable coal mine dust.
    After carefully considering all the facts, issues, and concerns 
raised by commenters during this rulemaking, MSHA concluded that, to 
proceed to a final rule would not be in the best interest of miners' 
health or the mining community. The Agency is re-proposing for further 
public comment, the rule which is the subject of this rulemaking.

B. Overview of Proposed Rule

    In preparing this proposed rule, MSHA has responded to comments 
that were made to the July 7, 2000 proposed rule. However, since this 
proposed rule differs from the earlier proposed rule in several areas, 
the agency may not have addressed each concern that was identified by 
the earlier commenters.
    MSHA believes that the proposed rule would significantly improve 
miners' health protection from the debilitating effects of occupational 
respiratory disease by limiting their exposures to respirable coal mine 
dust to no more than the applicable dust standard on each shift.\1\ 
Accordingly, this proposed rule revises 30 CFR part 70, subparts A, B, 
and C; amends two existing sections of part 75; and revises part 90, 
subparts A, B, C, and D.
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    \1\ For details, see the Quantitative Risk Assessment and 
Significance of Risk Sections.
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    Under this proposed rule, MSHA would be responsible for all 
compliance and abatement sampling, which is currently being carried out 
by the operator. This includes frequent sampling of each mechanized 
mining unit (MMU) and part 90 miner, sampling of outby Designated Areas 
(DAs) and occupations, and abatement sampling. This proposed rule 
specifies that compliance and abatement determinations will be based on 
the results of single samples. Also, only MSHA samples would be used to 
set a reduced dust standard when the quartz content of the respirable 
dust exceeds five percent.
    In response to comments raised in the earlier proposed rule, mine 
operators will continue to play a role in monitoring the mine 
environment. The proposed rule requires each underground operator to 
verify, through sampling, that the dust control parameters specified in 
a mine ventilation plan are effective in controlling the concentration 
of respirable coal mine dust and quartz dust at or below the 
verification limits of 2.0 mg/m3 and 100 [mu]g/m3 
respectively. For a sample to be valid for verification purposes, the 
amount of material produced must be at or above the ``verification 
production level'' or VPL. The VPL is defined as the tenth highest 
production level recorded in the most recent 30 production shifts. In 
addition, the engineering or environmental control parameters must not 
exceed 115% of the quantities specified in the ventilation plan and the 
sampling must take place over the entire production shift.
    The dust control parameters specified in mine ventilation plans 
must be designed to maintain dust concentrations at or below the 
applicable standard on each shift. If during the initial verification 
sampling, the VPL is achieved and dust concentrations are sufficiently 
low, the district manager could approve a plan based on one shift of 
sampling. However, if dust concentration measurements are higher, or if 
the actual production was less than the VPL, MSHA will require the 
operator to sample additional shifts. All verification samples would be 
submitted to MSHA for analysis. However, mine operators would not be 
cited if sample results show an overexposure so long as the operator 
takes steps to identify and correct the condition that caused the 
verification limit to be exceeded.
    Also, to confirm the continued effectiveness of the plan 
parameters, mine operators would be required to sample quarterly each 
producing MMU designated by MSHA under the same conditions that were in 
place when the plan parameters were initially verified. As in the 
earlier proposed rule, mine operators would be required to maintain 
records of the total amount of material produced by shift for each MMU.
    In the earlier proposed rule, commenters expressed concern about a 
provision in the July 7, 2000 proposed rule allowing the use of 
supplementary controls (powered, air-purifying respirators (PAPRs) and 
administrative controls), on an interim basis, in mines utilizing 
longwall mining technology. Commenters offered a wide range of opinions 
on this part of the proposed rule. Some commenters supported MSHA's 
decision to allow the use of supplementary controls, but criticized the 
proposed rule for being too restrictive. Other commenters objected to 
the proposed provision, claiming that the requirement was inconsistent 
with the provision of the Mine Act which prohibits respirators to be 
used as substitutes for engineering controls. These commenters were 
also concerned that operators would have no incentive to implement 
available engineering controls once they are permitted to use 
supplementary controls as proposed.
    This proposed rule recognizes that there may be circumstances 
where, even after implementing all feasible engineering or 
environmental controls, a mine operator may be unable to maintain 
concentrations at or below the verification limits. This includes 
operations that employ longwalls or other mining systems. In those

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instances, the proposed rule would allow a mine operator, with the 
approval of the Administrator of Coal Mine Safety and Health, to use 
either PAPRs or administrative controls or a combination of both to 
supplement engineering or environmental controls to reduce the dust 
exposure of individual miners. Approval to use supplementary control 
measures would be contingent on the mine operator adopting new 
engineering and environmental controls when they become available. The 
proposed rule also recognizes that there may be special situations that 
occur intermittently and for short periods of time where the approved 
dust control measures may not protect miners from overexposure. An 
example would be where the operator is required to mine through a rock 
parting with high quartz content. In these situations, the district 
manager may allow the operator to use PAPRs for a period not to exceed 
30 calendar days.
    This proposed rule would require that the mine operator provide a 
copy of any request for supplemental controls to the representative of 
the miners. This would provide an opportunity for miners' input prior 
to MSHA making any determination.
    A full discussion of these and other provisions is provided in the 
section-by-section analysis of this proposed rule.
    A number of commenters stated that MSHA's earlier proposed rule was 
incomplete because it did not address some key recommendations of by 
the Dust Advisory Committee, and by NIOSH in its Criteria Document (see 
sections II.E. and II.F. of the preamble). Some of these commenters 
expressed concern that the proposed rule failed to recognize and 
consider alternatives involving continuous dust monitoring technology. 
Since publication of that earlier proposed rule, technology has 
advanced to a point that will likely allow for continuous monitoring of 
dust exposures in the near future. Accordingly, this proposed rule has 
provisions that would allow mine operators to adopt such technology to 
meet the requirements for operator monitoring of dust control 
effectiveness and miner exposure.
    The recommendations regarding exposure limits for respirable coal 
mine dust and crystalline silica were beyond the scope of either the 
single sample or plan verification rules. In the interim, MSHA 
enforcement efforts continue to focus on lowering the quartz exposure 
of miners as recommended by the Dust Advisory Committee.
1. New Proposed Respirable Dust Sampling Program
    In order to improve miner confidence in the respirable dust 
sampling program, the proposed rule revises the existing operator 
sampling requirements for underground mines and for part 90 miners 
under 30 CFR parts 70 and 90, respectively, and provides that MSHA 
conduct compliance and abatement sampling.
    This proposed rule would result in fewer shifts being sampled than 
under existing requirements. However, MSHA believes that the amount of 
sampling it will conduct under the proposed rule will be more 
protective because a greater number of individual compliance 
determinations would be made. MSHA samples the Designated Occupation 
(DO) and at least four other occupations, if available, on each 
sampling inspection. Also, since all MSHA sampling is unannounced, 
sampling will occur under conditions that are more typical of the 
actual mining environment. In addition, compliance determinations would 
be based solely on a single-sample measurement and not on an average of 
multiple shift measurements. Multiple shift measurements can mask 
overexposures by diluting a measurement of high dust exposure with 
lower measurements made on different shifts or at different 
occupational locations.
    Commenters to the July 7, 2000 proposed rule also criticized MSHA 
for failing to fully incorporate the preamble discussion on the 
Agency's sampling procedures into the proposed regulation to prevent 
those procedures from being changed or modified in the future. MSHA 
does not believe that it would be appropriate to incorporate agency 
enforcement procedures into rules that are designed to regulate the 
mining industry. It is necessary for MSHA to retain the ability to 
modify its enforcement policies and procedures in response to, among 
other things, case law, new health or safety concerns, major mine 
emergencies, or changes in technology which may require the agency to 
redirect its efforts to protect miner health and safety.
    In order to provide the mining community with an understanding of 
how the agency intends to enforce this proposed rule, MSHA has 
published a draft of Chapter 1 (Respirable Dust) of MSHA's health 
inspection procedures (see http://www.msha.gov) which it intends to 
adopt as its enforcement strategy when the final rule becomes 
effective.
2. Verification of Ventilation Plan Effectiveness
    The proposed rule requires that each underground coal mine operator 
must have a mine ventilation plan verified by operator sampling. The 
verified plan must be effective in controlling respirable dust in each 
MMU under typical mining conditions prior to approval of the plan by 
the district manager. In addition, mine operators would be required to 
sample quarterly each producing MMU designated by MSHA to determine if 
the dust control measures specified in the approved ventilation plan, 
continue to protect miners from overexposure. No citations would be 
issued to mine operators based on the results of this sampling as long 
as the operator takes steps to eliminate the conditions which caused 
any overexposure identified through such sampling.
    Consistent with the Mine Act and its implementing regulations, this 
proposed rule preserves the primacy of engineering controls to the 
extent that they are technologically and economically feasible.
    The dust control parameters specified in the mine ventilation plans 
should be designed to control respirable dust and prevent overexposures 
on individual shifts. These plans should accurately reflect the 
engineering or environmental controls that are suitable to the mining 
system and operating conditions at the MMU.
    Under the proposed rule, the mine operator will collect respirable 
dust samples to demonstrate the adequacy of the dust control parameters 
specified in the mine ventilation plan in maintaining the concentration 
of respirable coal mine and quartz dust at or below the ``verification 
limits'' of 2.0 mg/m3 and 100 [mu]g/m3, 
respectively. The adequacy of the dust control parameters must be 
demonstrated on shifts during which the amount of material produced is 
at or above the ``verification production level'' (VPL) or the tenth 
highest production level recorded in the most recent 30 production 
shifts, and using only the engineering or environmental control 
parameters proposed in the ventilation plan, at levels not exceeding 
115 percent of the quantities specified in the plan.
    The proposed rule would require mine operators to: (a) Set and 
maintain the dust control parameters during verification sampling at 
levels specified in the plan; (b) maintain and make available to MSHA 
records of the amount of material produced by each mechanized mining 
unit during each production shift; (c) provide additional

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information in mine ventilation plans such as the VPL, shift length, 
etc.; and (d) provide the miners' representative the opportunity to 
participate in the plan verification process.
    During sampling to secure plan approval, the district manager could 
approve a plan based on one shift of sampling if the VPL is achieved, 
and respirable dust concentrations are sufficiently low. However, if 
dust concentration measurements are higher, or if the actual production 
was less than the VPL, the mine operator would be required to sample 
additional shifts.
3. Measures To Supplement Engineering Controls to Reduce Exposures
    Under the proposed rule, if a ventilation plan cannot be verified 
using all feasible engineering or environmental controls, the mine 
operator may be permitted to use either powered, air-purifying 
respirators (PAPRs) or verifiable administrative controls, or a 
combination of both, as a supplemental means of control (see section 
III.D. Hierarchy of Dust Controls). MSHA may, under certain conditions, 
approve such use only after the Administrator for Coal Mine Safety and 
Health has determined that all feasible engineering or environmental 
controls have been adopted in the ventilation plan, but miners continue 
to be at risk of overexposure. District managers may also approve the 
use of supplementary controls for limited periods of time when unusual 
or intermittent adverse conditions could result in miners not being 
fully protected by the approved dust control plan.
    These and other provisions of the proposed rule are explained in 
more detail in the Section-by-Section Discussion of this preamble.

C. Control of Coal Mine Respirable Dust

    Maintaining a work environment free of excessive levels of 
respirable coal mine dust and quartz dust (hereafter referred to as 
``respirable dust'') is essential for long-term health protection. 
Section 202(b)(2) of the Federal Mine Safety and Health Act of 1977 
(Mine Act) requires each operator to continuously maintain the average 
concentration of respirable dust in the mine atmosphere, during each 
shift to which each miner in the active workings of such mine is 
exposed, at or below 2.0 milligrams of respirable dust per cubic meter 
of air (mg/m3). Under the Mine Act and the implementing 
regulations, when respirable coal mine dust contains more than five 
percent quartz, the applicable dust standard is further reduced by 
means of a formula. Although MSHA does not enforce a separate standard 
for respirable quartz dust, the formula (10 divided by the percentage 
quartz) used to establish an applicable dust standard, in effect, 
limits respirable quartz concentrations to 100 [mu]g/m3 (as 
an MRE equivalent).
    Consistent with the Mine Act and MSHA regulations, the primary 
focus of the federal respirable dust program is on controlling the 
concentrations of respirable dust in the environment where miners work 
or travel through the application of feasible engineering or 
environmental control measures. Engineering or environmental controls 
for respirable dust in the mine environment are the proven dust-control 
techniques and the principal methods for protecting miners' health. 
These include all methods for controlling the quantity of respirable 
dust in the air that a miner breathes by either reducing dust 
generation, or by suppressing, diluting, capturing, or diverting the 
dust that is being generated by the mining process. Under the Mine Act, 
the mine operator has primary responsibility for implementing a program 
to control respirable dust so that all miners work in an environment 
free of excessive levels of respirable dust. Mine operators must 
develop, implement, and maintain effective measures to control the 
level of respirable dust in the mine environment, and evaluate these 
control measures at regular intervals to ensure that they function as 
intended. These control measures, or ``dust control parameters,'' are 
required to be specified in the dust control portion of the operator's 
mine ventilation plan under Sec.  75.370.
    Mine ventilation plans are a long-recognized means of addressing 
health issues that are mine-specific and for achieving work 
environments that are free of excessive concentrations of respirable 
dust. Currently, section 75.370 requires each operator of an 
underground coal mine to develop and follow a ventilation plan that is 
designed to control methane and respirable dust in the mine. The plan 
must be suitable to the conditions and mining systems employed at the 
mine. Although ventilation plans must be designed to control respirable 
dust, there has been no requirement that the plan's effectiveness be 
verified.
    The dust control portion of the mine ventilation plan is a key 
element of the operator's strategy to control respirable dust in the 
working environment of each mechanized mining unit (MMU) during each 
shift. Existing section 70.2 defines, in part, a MMU to mean ``a unit 
of mining equipment, including hand loading equipment, used for the 
production of material.'' The plan provides a description of the 
specific engineering control measures in use. The plan also contains 
procedures for maintenance of specific dust control equipment, such as 
scrubbers, dust collectors on roof bolters, and spray nozzles, or for 
the replacement of cutting picks to minimize dust generation. Once 
approved by the district manager, the dust control parameters must be 
employed on a continuous basis to provide protection from the hazards 
of respirable dust to coal miners. By insuring that the parameters are 
being maintained on each production shift, miners can be assured that 
respirable dust levels are being adequately controlled without the need 
to continuously monitor respirable dust levels in the mine environment. 
Implementing dust control parameters that have been determined 
effective under typical mining conditions, and maintaining these 
controls in proper working order, provides reasonable assurance that no 
miner will be overexposed. Because technology that continuously 
monitors respirable dust and displays dust concentrations in real-time 
is not yet available for use in underground coal mines, the 
implementation of effective ventilation plans is the only practical 
means of reasonably ensuring, on a continuous basis, that miners are 
not overexposed.
    In 1996, MSHA implemented revised ventilation standards which, 
among other provisions, required an on-shift examination of the dust 
control parameters before coal production begins on each MMU to assure 
compliance with the dust control parameters specified in the 
ventilation plan. Based on the recommendations of MSHA's Coal Mine 
Respirable Dust Task Group (MSHA, 1992), this requirement is intended 
to focus attention on the need for properly functioning dust controls 
before production begins. On-shift examinations of dust control 
parameters under existing Sec.  75.362 are one important component for 
an effective respirable dust control strategy. Recent advances in 
technology make it feasible to continuously monitor certain parameters, 
such as air quantity and velocity and spray water flow rate and 
pressure (Spencer, et al. 1996). Existing Sec. 75.362 encourages the 
use of such monitors as it would eliminate the need for periodic 
physical measurements of some dust controls to verify if they are 
operating properly. Although current technology allows real-time data 
to be obtained on certain dust control parameters such as air 
quantities,

[[Page 10788]]

MSHA is not aware of its use by any operator.
    Since establishment of the first comprehensive dust standards in 
1969, the implementation of ventilation plans by mine operators and 
their enforcement by MSHA has had a significant impact on control of 
dust levels in underground coal mines. For example, based on federal 
mine personnel sampling results, the average dust concentration in the 
environment of a continuous miner operator (occupation code--036) has 
been reduced by 87 percent over the past 32 years, from 7.7 mg/
m3 to approximately 1.0 mg/m3. This accounts for 
the significant decline in the percentage of operator continuous miner 
designated occupation (DO) samples with concentrations of 2.1 mg/
m3 or higher, from 49 percent (over 32,000 samples/shifts) 
in 1971, to 7 percent (over 1,250 samples/shifts) during the first 
three quarters of 2002. Analysis of all valid operator DO samples 
collected during the same time period as above indicates that in 1971, 
53,463 (44 percent) of the 122,404 shifts sampled, were at or above 2.1 
mg/m3, compared to 1,450 (7 percent) of the 19,336 shifts 
sampled in 2002 (MSHA, DO Samples by Calendar Year, 2002). Despite this 
progress, MSHA has found evidence that a significant number of 
overexposures still occur on the shifts sampled during which the 
approved dust control parameters are operating at or above approved 
levels. This evidence suggests that it is highly probable that some 
miners are overexposed to respirable dust on shifts not sampled by 
either the operator or by MSHA. In addition, recent medical 
surveillance data suggests that miners continue to be at risk of 
developing simple coal workers' pneumoconiosis (CWP), progressive 
massive fibrosis (PMF), and silicosis (Elam, April 1999).
    Two expert panels, that reviewed the federal program designed to 
prevent pneumoconiosis among coal miners, found that certain aspects of 
the current respirable dust program limit MSHA's ability to determine 
the adequacy of the dust control parameters under typical mining 
conditions. Both the Coal Mine Respirable Dust Task Group, (Task Group) 
an interagency task group established in 1991 by the Assistant 
Secretary for Mine Safety and Health, and the Advisory Committee on the 
Elimination of Pneumoconiosis Among Coal Mine Workers, (Dust Advisory 
Committee) established in 1995 by the Secretary of Labor, considered 
all aspects of the respirable coal mine dust control program and made 
recommendations for improvement. In addition, in November 1995, NIOSH 
issued a criteria document that contained recommendations to improve 
miner health protections.

D. Coal Mine Respirable Dust Task Group

    In response to concerns about the Federal coal mine dust program 
(MSHA, 1992), MSHA's Task Group undertook an extensive review of the 
program to control respirable coal mine dust and made recommendations 
to improve the program in 1991. As part of that review, MSHA developed 
a special respirable dust ``spot inspection program'' (SIP). This 
program was designed to provide the Agency and the Task Group with 
information on the dust levels to which underground miners are 
typically exposed.
    The Task Group found that MSHA's current program did not promote 
the development and implementation of quality plans. Based on its 
review of a representative number of dust control plans, the Task Group 
found that some plans lacked specificity or did not include all the 
dust control parameters actually used. For example, the plans for three 
major underground coal mines listed the air quantity, the primary means 
of controlling concentrations of respirable coal mine dust, to be 
18,000 cubic feet per minute (cfm) in the mining section. The actual 
quantities measured by MSHA samples at these mines during the SIP 
varied from 40,000 cfm to over 120,000 cfm.
    Based on a review of MSHA Form 2000-86 (Revised), Respirable Dust 
Sampling and Monitoring Data, similar differences were found between 
air quantities specified in approved ventilation plans and the levels 
observed at a number of longwall MMUs inspected in 1999. For example, 
20 of the 47 longwall MMUs were using significantly more air than 
specified in the ventilation plan (MSHA, September 1999). Under these 
circumstances, it would be impossible to assess whether the air volume 
specified in the plan was adequate to maintain dust concentrations at 
or below the applicable dust standard. It should be noted that air 
quantities, air velocities, water spray pressures, and other control 
parameters, specified in the plan are considered to be minimum 
requirements and MSHA encourages mine operators to exceed their plan 
parameters, but only after the levels specified in the plan have been 
shown to be effective under the conditions in effect during sampling. 
In addition, a lack of specificity in some plans made it difficult for 
MSHA samples to determine whether the operator was complying with the 
approved plan. Although several plans indicated that the mining 
equipment was to be provided with water sprays, the plan did not 
specify the location of the sprays or the water pressure at the spray 
nozzle.
    Currently, MSHA relies on information provided by the operator to 
determine at what production level the plan should be evaluated. No 
production records are required for each MMU. Although operators must 
submit production data on a quarterly basis, the data is compiled for 
the entire mine. In addition, these quarterly reports provide 
information on the amount of clean coal produced, which are much lower 
than the tonnage of total material produced, and are not useful for 
establishing what constitutes ``normal production shifts'' for sampling 
purposes.
    The Task Group determined that the use of low production levels for 
evaluating the effectiveness of dust control parameters can result in 
marginal or inadequate plans. Therefore, the Task Group recommended 
that MSHA require mine ventilation plans to be effective under typical 
mining conditions. A more detailed discussion of the impact of 
production on the quality of dust control parameters specified in mine 
ventilation plans is contained in sections III.C.1. and IV.B. of this 
preamble.
    A survey conducted by MSHA in August of 2002 found that 48 percent 
of producing MMUs worked at least a 9-hour shift. The Task Group 
concluded that current regulations limiting the duration of sampling to 
eight hours do not provide for adequate assessment of respirable dust 
exposure during nontraditional shifts of more than eight hours.
    Implementation of the Task Group recommendations would have 
required regulatory change. The effort to implement these changes was 
suspended pending the deliberations and recommendations of the Advisory 
Committee on the Elimination of Pneumoconiosis Among Coal Mine Workers, 
which was convened in 1995.

E. NIOSH Criteria Document

    On November 7, 1995, MSHA received the document, Criteria for a 
Recommended Standard: Occupational Exposures to Respirable Coal Mine 
Dust, (Criteria Document) from the National Institute for Occupational 
Safety and Health (NIOSH). That document contains recommendations to 
minimize the health risks encountered by surface and underground coal 
miners due to their occupational exposure to respirable coal mine dust 
and

[[Page 10789]]

crystalline silica, hereafter referred to as ``quartz.''
    According to NIOSH,

    By means of criteria documents, NIOSH communicates these 
recommended standards to regulatory agencies (including the 
Occupational Safety and Health Administration (OSHA) and MSHA) and 
to others in the community of occupational safety and health * * *. 
In addition to transmitting these documents to the Department of 
Labor, NIOSH also distributes them to health professionals in 
academic institutions, industry, organized labor, public interest 
groups, and other government agencies. (NIOSH, 1995, p. iii).

    Pursuant to the Mine Act, MSHA was required to issue a public 
response to this criteria document within 60 days. The statutory 
deadline for MSHA's response fell on January 7, 1996. In the fall of 
1995, there was a lapse in funding for the Federal government, and the 
Department of Labor was unable to take timely action on this matter (61 
FR 731). On April 25, 1996, MSHA published its response to the Criteria 
Document in the Federal Register (61 FR 18308) stating it would develop 
its regulatory response to the Criteria Document in conjunction with 
its response to the outcome of the Dust Advisory Committee. (See 
section II.F.).
    Some commenters criticized the earlier proposed rules for not 
addressing all the recommendations of the Criteria Document. During the 
August 2000 hearings when these comments were made, a NIOSH 
representative stated, ``* * * strong steps are necessary * * * 
oftentimes they do need to be incremental in nature.'' Among the 
relevant recommendations from the Criteria Document raised by 
commenters were the following:
    [sbull] Sampling should be conducted with a device that operates in 
accordance with NIOSH Accuracy Criteria Document, using the 
international definition of respirable dust.
    [sbull] Single-shift measurements should be used to determine 
noncompliance.
    [sbull] The exposure limit for respirable coal mine dust should be 
limited to 1.0 mg/m3 as a time-weighted-average (TWA) 
concentration for up to 10 hours per day, during a 40-hour workweek.
    [sbull] There should be a gravimetric standard for silica of 0.05 
mg/m3 as a TWA for up to 10 hours per day, for a 40-hour 
workweek.
    [sbull] Sampling goals should include determining the effectiveness 
of a dust control system and determining compliance with exposure 
limits to ensure that exposure conditions are comparable between shifts 
which are sampled and those which are not.
    [sbull] Engineering controls and work practices should reflect 
reasonable efforts to reduce exposures to respirable coal mine dust 
below the exposure limit.
    [sbull] MSHA should not make an upward adjustment of the exposure 
limit to account for measurement uncertainties (i.e., citation 
threshold values (CTV)). (See section III.A.4.a.).
    [sbull] Continuous monitoring devices should be developed for use 
in sampling respirable coal mine dust.
    [sbull] Sampling frequency should be enough that a significant and 
deleterious change in the contaminant generation process or exposure 
controls is not permitted to persist.
    MSHA has carefully considered the applicability of each NIOSH 
recommendation to reduce miners' exposure to respirable coal mine dust, 
and the agency has integrated these recommendations into our programs, 
policies, and promulgation of standards. The proposed rule published 
today are, in part, responsive to NIOSH's recommendations.
    For example, the single sample rule, for which the record is 
reopened in today's Federal Register notice is responsive to the 
Criteria Document. This rule was jointly developed with NIOSH.
    The two recommendations regarding exposure limits for respirable 
coal mine dust and quartz dust are beyond the scope of either the 
single sample or plan verification proposed rules.
    MSHA and NIOSH agree that the level of ``coal production 
significantly affects the amount of airborne respirable coal mine 
dust'' (NIOSH 1995, p. 86). NIOSH recommended that ``The mine operator, 
therefore, should establish a production-level threshold to ensure that 
exposure conditions are comparable between sampled and unsampled 
shifts'' (NIOSH, 1995, p. 86). NIOSH recommended that, for a production 
shift to be considered a normal production shift, it must produce at 
least 80% of the average production, over the last 30 production 
shifts.
    Through this plan verification proposed rule, MSHA would require 
operators to design their ventilation plan to be effective in 
controlling respirable coal mine dust at or above the ``verification 
production level'' (VPL). The VPL is defined as the tenth highest 
production level recorded in the most recent 30 production shifts. This 
quantity generally exceeds the production criteria recommended by NIOSH 
by a substantial amount.
    In addition, for MSHA to approve an operator's mine ventilation 
plan, the plan's dust control parameters must be shown to be effective 
in meeting the verification limits of 2.0 mg/m3 for 
respirable coal mine dust and 100 [mu]g/m3 for respirable 
quartz dust, under typical mining conditions. MSHA expects that most 
ventilation plans will be verified at or below those values. Therefore, 
for most mechanized mining units (MMUs), engineering controls will be 
in place that can control respirable coal mine dust at or below the 
exposure limit. (See chapter IX. Costs in the Preliminary Regulatory 
Economic Analysis (REA) for details).
    Citation threshold values (CTV) are calculated to ensure that 
citations are issued only when a single sample measurement 
demonstrates, with at least 95-percent confidence, that the applicable 
dust standard had been exceeded.\2\ Thus, before issuing a citation, 
the Secretary requires a high level of confidence that there has been 
an overexposure. Even so, a dust concentration measurement that falls 
between the applicable dust standard and the corresponding CTV does not 
demonstrate that the sampled environment is in compliance. MSHA would 
identify such environments for further sampling to determine if 
engineering controls are adequately protective.
---------------------------------------------------------------------------

    \2\ CTVs are listed in Table 70.2
---------------------------------------------------------------------------

    As mentioned earlier, several commenters to the 2000 proposal 
expressed concern that, under MSHA's proposed sampling program, the 
number of shifts to be sampled would be less than under the current 
operator and MSHA sampling programs combined. Although MSHA will sample 
fewer shifts than what was recommended by the Dust Advisory Committee, 
the number of compliance determinations per MMU will not decrease. 
Under the existing sampling programs, each MMU averages 10 compliance 
determinations per year.\3\ Each of these compliance determinations is 
based on the average

[[Page 10790]]

of five 8-hour exposure measurements. (See III.A.2. Post-1980 Sampling 
Program). Under this proposed rule, each MMU will average significantly 
more compliance determinations annually using the results of single 
sample measurements taken by MSHA personnel (30 CFR 70.202).\4\ This 
increase does not reflect the additional compliance determinations that 
will be made as a result of sampling, concurrently with MMUs, each 
intake DA, roof bolter DA and outby occupations.
---------------------------------------------------------------------------

    \3\ Currently, six of the ten compliance determinations are 
based on the average of five operator, ``designated occupation'' 
(DO) exposure measurements. Each of these measurements is collected 
on a different shift within a bimonthly cycle. The remaining four 
determinations are based on the average of five inspector samples 
taken quarterly on different occupations from a MMU. Since the 
publication of the earlier proposed rule, the number of yearly MSHA 
sampling inspections at each MMU was reduced from six to four. This 
was the result of the impact on Agency resources due to a decision 
by the Federal Mine Safety and Health Review Commission that 
violations of the applicable dust standard must be based on samples 
taken on multiple shifts. Prior to that decision, MSHA compliance 
decisions were based on multiple samples taken on a single-shift. 
Accordingly, there has been a need to increase the number of shifts 
of MSHA sampling at MMUs where overexposures are found on the first 
sampling shift. This results in fewer sampling inspections being 
available at other MMUs.
    \4\ On a re-occuring basis MSHA will sample an average of five 
different occupations on each producing MMU. Since every measurement 
will be compared with the CTV corresponding to the applicable dust 
standard in effect, MSHA will be making significantly more 
compliance determinations yearly than under the current operator and 
MSHA sampling programs combined.
---------------------------------------------------------------------------

    The new sampling program will be far more effective in monitoring 
the quality of the mine air that miners must breathe, and in preventing 
overexposures on individual shifts, because MSHA will be making 
compliance determinations using measurements that are more 
representative of the dust concentrations to which miners are exposed 
on individual shifts. As such, MSHA believes the new MSHA sampling 
program addresses the NIOSH recommendation that sampling be conducted 
``frequently enough that a significant and deleterious change in the 
contaminant generation process or exposure controls is not permitted to 
persist'' (NIOSH, 1995, p. 85).
    Significant progress in monitoring technology has been made since 
MSHA published the earlier proposed rule on plan verification. The 
agency has been informed by NIOSH that a continuous dust monitor may be 
available for in-mine use by the middle of 2004. Accordingly, as 
recommended in the criteria document, MSHA is proposing a new standard 
that would permit operators to use this new technology in conjunction 
with existing dust controls specified in the ventilation plan to 
prevent overexposures on individual shifts.
    Today's proposed rule does not adopt all the Criteria Document 
recommendations since many of the recommendations are outside the scope 
of these rules. However, MSHA continues to be committed to the 
principles that ``preventive efforts [must] be focused primarily on 
reducing work exposures (NIOSH, 1995).''
    The Secretary of Labor and the Secretary of Health and Human 
Services believe that miners' health will be further protected from the 
debilitating effects of occupational respiratory disease by limiting 
their exposures to the applicable dust standard through the 
implementation of the single sample rule which conforms to the NIOSH 
Accuracy Criteria. Furthermore, as stated by NIOSH during the hearings:

    NIOSH does support efforts by MSHA and anyone else that will 
reduce miners' exposures to dust and silica dust and also eliminate 
or at least reduce significantly the incidence of the diseases * * 
*.

    MSHA believes that this proposed plan verification rule provides an 
improved program for measuring, monitoring, and reducing overexposures 
to respirable coal mine dust and quartz dust, under typical mining 
conditions. As such, it greatly advances the level of health protection 
afforded underground miners and is consistent with recommendations 
issued by NIOSH in its Criteria Document.

F. Advisory Committee on the Elimination of Pneumoconiosis Among Coal 
Mine Workers

    On January 31, 1995, the Secretary of Labor established the 
Advisory Committee on the Elimination of Pneumoconiosis Among Coal Mine 
Workers (Dust Advisory Committee). The Dust Advisory Committee was 
chartered to ``make recommendations for improving the program to 
control respirable coal mine dust in underground and surface mines in 
the United States.'' The Dust Advisory Committee identified and 
addressed many of the same issues considered by the Task Group. 
Findings and consensus recommendations were developed for each issue 
(MSHA, 1996). The Dust Advisory Committee concluded that the dust 
control portion of the mine ventilation plan is the key element of an 
operator's strategy to control respirable dust in the work environment. 
They concluded that the initial evaluation, approval, in-mine 
verification and monitoring to demonstrate the effectiveness of the 
operator's proposed dust control plan is critical for the protection of 
miners from lung disease. Also, believing that the credibility of the 
current system of mine operator sampling to monitor compliance with 
exposure limits has been severely compromised, the Dust Advisory 
Committee concluded that restoration of miner and mine operator 
confidence in the respirable coal mine dust sampling program should be 
one of MSHA's highest priorities. Accordingly, there was unanimous 
agreement that in order to restore confidence in the program MSHA 
should take full responsibility for all compliance sampling currently 
being carried out by mine operators under 30 CFR parts 70 and 90.
    The November 1996 Dust Advisory Committee Report recommended 
numerous improvements for the federal program to protect miners from 
simple CWP, PMF, and silicosis. Of these, the following have been 
incorporated in this proposed rule:
    1. MSHA will take full responsibility for all compliance sampling 
(periodic and abatement) at a level which ensures that representative 
samples are collected of respirable dust exposures under usual 
conditions of work without adversely impacting the Agency's resources 
and responsibilities.
    2. Operators would be required to verify, through sampling, the 
effectiveness of the dust controls in the ventilation plan prior to 
approval by MSHA. The plan must be verified utilizing only those 
controls that are listed in the plan. In addition, mine operators would 
sample designated MMUs quarterly to ensure that the dust controls 
continue to protect miners from overexposure.
    3. MSHA will redefine the range of production levels which must be 
maintained during sampling to verify the plan. The value will be 
sufficiently close to maximum anticipated production levels in order to 
reasonably ensure that the plan is effective under typical operations.
    4. MSHA will review compliance and production records to determine 
when there is a need for plan verification and modification.
    5. MSHA would allow mine operators to use newly developed 
technology to continuously monitor the work environment and prevent 
overexposures on individual shifts.
    This proposed rule is intended to eliminate overexposures on 
individual shifts and to restore the confidence of miners and mine 
operators in the respirable coal mine dust sampling program by 
addressing the shortcomings identified by the Task Group and the Dust 
Advisory Committee in the current respirable coal mine dust program. 
This proposed rule would revise the operator dust sampling programs 
under 30 CFR parts 70 and 90 and require the implementation of mine 
ventilation plans demonstrated to be effective in maintaining 
respirable dust at or below applicable dust standards on each shift. 
These ventilation plans will be verified through sampling by the mine 
operator, and the plans' effectiveness may be monitored on a quarterly 
basis by the operator. MSHA intends to periodically monitor operator 
verification sampling and on a recurring basis will conduct sampling on 
each MMU to assure

[[Page 10791]]

compliance with the provisions of the ventilation plan and the 
applicable dust standard. A notice reopening the record regarding the 
use of single-shift sample measurements of respirable coal mine dust to 
determine average concentration is also published in today's Federal 
Register.
    MSHA recognizes that the Dust Advisory Committee made several 
recommendations that also impact on surface coal mine workers. These 
surface coal mine issues are beyond the scope of this proposed rule and 
will be addressed by the Agency at a later date.
    In response to comments received, MSHA has specifically stated in 
this proposed rule that the representative of miners has the right to 
observe MSHA sampling with no loss of pay as recommended by the Dust 
Advisory Committee. The proposed rule also allows the miners' 
representative the opportunity to participate in operator sampling to 
verify the ventilation plan. However, such participation would be with 
no loss of pay, only when MSHA personnel are present to observe that 
sampling. This proposed rule does not specifically address the 
committee's recommendations concerning specialized miner training on 
verification sampling procedures. However, MSHA does intend, during the 
implementation of any final rule, to provide training to miners, 
miners' representatives and mine operators on the requirements of the 
new regulations. In addition, agency personnel are available to provide 
training to miners and their representatives on the verification 
procedures as needed.
    This proposed rule does not incorporate full-shift sampling as 
recommended by the Dust Advisory Committee. In this proposed rule, MSHA 
does require that verification and operator quarterly sampling occur 
for the entire production shift since the purpose of that sampling is 
to evaluate the effectiveness of the dust controls on the MMU. 
Therefore, outby travel time is not included. With regard to compliance 
sampling by MSHA, the agency believes that sampling portal to portal 
for the entire shift or eight hours, whichever is less, provides the 
agency with sufficient data to determine if the dust control measures 
outlined in the ventilation plan are adequate and being followed or to 
determine if overexposures are occurring.
    Although the Dust Advisory Committee also recommended that MSHA 
adjust the exposure limit to account for extended work weeks, such a 
change is considered to be outside the scope of this rulemaking.
    MSHA has clarified in this proposed rule that the Secretary will 
cite for overexposure when an MSHA sample demonstrates that the 
applicable dust standard has been exceeded, based on the citation 
threshold value (CTV). In response to concerns that, by using a CTV, 
MSHA is increasing the standard, MSHA has clarified that respirable 
dust concentration levels must always be maintained at or below the 
applicable dust standard. In order to obtain ventilation plan approval 
from MSHA, operators must demonstrate that the dust control parameters 
adequately prevent excessive dust concentrations on individual shifts. 
The plan's effectiveness is evaluated against the applicable dust 
standard itself--not the CTV--and must be demonstrated at a high level 
of confidence.
    This proposed rule also provides for the limited use of measures to 
supplement engineering or environmental controls for exposure control. 
These supplemental measures would be permitted at certain times when 
the Administrator for Coal Mine Safety and Health has determined that 
all feasible engineering and environmental controls have been applied 
and the mine operator is unable to verify the ventilation plan. 
Supplementary controls may also be approved by MSHA for short-term use 
to protect individual miners when operators encounter intermittent, 
adverse conditions under which exposures cannot be maintained within 
the applicable standard using the approved dust control parameters.
    Finally, MSHA received comments suggesting that this rule address 
the Dust Advisory Committee recommendation to establish a separate 
silica standard. This issue is outside the scope of this rule.

III. General Discussion

A. Proposed Reforms to the Respirable Dust Monitoring Program

    One of the Dust Advisory Committee's key recommendations was that 
MSHA take full responsibility for all compliance sampling at a level 
which assures representative samples of respirable dust exposure under 
usual conditions of work. This was based on the belief that one of 
MSHA's highest priorities must be to restore the confidence of miners 
and mine operators in the respirable coal mine dust sampling program.
    Accordingly, MSHA is proposing to revise the operator dust sampling 
programs under current 30 CFR parts 70 and 90 and to take full 
responsibility for all compliance sampling (i.e., periodic and 
abatement sampling) in a manner that it believes will be more 
protective than the current operator sampling program. MSHA intends to 
monitor miners' dust exposure and compliance with the dust control 
provisions of the approved mine ventilation plan, or with the 
respirable dust control plan for a Part 90 miner at underground mines, 
in accordance with the procedures and guidelines established in Chapter 
1 of the Coal Mine Health Inspection Procedures Handbook.
(a) Compliance Sampling
    MSHA will routinely collect samples from the working environment of 
the DO, Part 90 miners and, if available, four or more other 
occupations working in each producing MMU. The data from this sampling 
will be utilized by MSHA to formulate an effective compliance sampling 
strategy that focuses on the performance of individual sampling 
entities and to target MMUs for operator quarterly sampling. The 
strategy will be detailed in the Agency's respirable dust inspection 
procedures.
    Each DA inby the section dump point, such as intake and roof bolter 
DAs, and other DAs that can be sampled concurrently with the MMU will 
also be sampled routinely. If the MMU sampled is operating with 
approved supplemental control measures, the five or more occupations 
sampled will include the DO and all miners whose exposure is being 
controlled through the use of PAPRs or verifiable administrative 
controls.
    Since MSHA's inspections are unannounced, the primary objective is 
to assess the respirable dust conditions to which miners are exposed 
under the operating conditions in effect at the time of sampling (i.e., 
production level, air quantities and velocities, etc.). All respirable 
dust samples collected will be considered valid, unless voided by MSHA 
for other reasons, such as a malfunctioning pump. Because the primary 
purposes are to measure the quality of the mine air miners breathe and 
to evaluate the operating conditions on a particular shift, the Agency 
believes there is no reason to invalidate any sample if a certain level 
of production is not attained as under the previous sampling 
procedures. Compliance sampling results, however, will provide MSHA 
personnel with sufficient information to make a sound engineering 
judgement about the effectiveness of the dust control parameters in 
use.
    Also, since the purpose of this sampling is not intended to 
evaluate plan effectiveness, the term ``full shift'' for purposes of 
compliance and

[[Page 10792]]

abatement sampling will continue to mean the entire work shift 
including travel time but excluding any time in excess of 480 minutes. 
This is different from the definition of ``full shift'' that is 
proposed for verification sampling. For purposes of verification 
sampling, ``full shift'' would mean an entire work shift during which 
material is produced by a MMU. MSHA solicits comments on whether full 
shift for compliance sampling should be defined in the same way as for 
verification sampling.
    MSHA is proposing to continue the current policy of sampling outby 
locations only once per year. The historical data that has been 
collected by MSHA personnel at outby locations confirms our belief 
that, if the working sections are in compliance with the applicable 
dust standard and if controls are in place at outby dust generating 
locations, workers throughout the mine are being protected from 
overexposure. MSHA personnel will continue to sample each DA located 
outby the section dump point on a production shift and any other dust-
generating sources that can be sampled concurrently with the DA.
    MSHA will issue a citation for noncompliance when a valid single 
sample measurement, expressed as an equivalent dust concentration, 
meets or exceeds the Citation Threshold Value (CTV) corresponding to 
the applicable dust standard in effect.
    The current CTVs are contained in Table 70.2 of this proposed rule. 
The CTVs and an explanation of how they were derived was originally 
published in the Federal Register notice of February 3, 1998 (63 FR 
5687), entitled ``Coal Mine Respirable Dust Standard Noncompliance 
Determinations.'' As explained in that notice and in Appendix ``C'' of 
the current notice of proposed rulemaking, each CTV is calculated so 
that citations are issued only when a single-shift measurement 
demonstrates noncompliance at least at a 95 percent confidence level.
    Noncompliance determinations based on single-shift measurements 
will reduce the chances for failure to cite cases of noncompliance. 
According to the federal sampling inspections conducted in 1995, only 
132 MMUs were found to be in violation of the applicable dust standard. 
These MMUs were cited under the existing enforcement policy of 
measurement averaging, compared to 545 MMUs that would have been 
citable using single sample measurements in combination with the CTV 
table. This clearly demonstrates that the new enforcement strategy will 
not compromise miners' health, instead it would have identified 413 
additional instances of overexposure. Otherwise, these overexposures 
would continue to go uncorrected under the previous policy of 
measurement averaging.
    Many commenters believed that miners would receive greater 
protection if MSHA cited for noncompliance whenever any single-shift 
measurement exceeded the applicable dust standard. MSHA has carefully 
considered, but rejected this suggestion. Such citations may not be 
sustained with a sufficient degree of confidence for enforcement 
action. If the mine environment is sufficiently controlled, the 
likelihood that a particular measurement exceeds the applicable dust 
standard, but not the CTV, due to measurement error, can actually 
exceed the likelihood that the measurement exceeds the standard due to 
excessive dust concentration. A thorough technical discussion of this 
issue is provided at 63 FR 5709-5712 (Appendix D of the Federal 
Register notice cited above) and is incorporated into this notice by 
reference. Basing noncompliance determinations on a single sample 
measurement, in conjunction with the CTV table, will improve working 
conditions for miners.
    Many commenters contended that a policy of citing in accordance 
with the CTV table, rather than citing whenever a measurement exceeds 
the applicable dust standard, would effectively increase the allowable 
dust concentration limit. These commenters expressed concern that MSHA 
was raising the applicable dust standard when it proposed to cite 
violations only when the measurement demonstrated noncompliance at a 
high level of confidence.
    The CTVs do not raise the applicable dust standard. Instead, MSHA 
must ensure a sufficiently high level of confidence in noncompliance 
determinations to withstand a legal challenge. For those MMUs with 
measurements above the applicable dust standard but below the CTV, MSHA 
will thoroughly review their dust control parameters. Special emphasis 
will be directed to working environments required to comply with 
standards below 2.0 mg/m3. As a result of such reviews MSHA 
may initiate additional sampling.
    The Secretary has concluded that using single sample measurements 
for noncompliance determinations in accordance with the CTV table 
neither increases nor decreases the applicable dust standard. Operators 
are required to maintain compliance with the applicable dust standard 
at all times. Dust controls must be verified as adequate to maintain 
dust concentrations at or below the applicable dust standard on all 
shifts, not merely at or below the CTV. If a measurement exceeds the 
applicable dust standard by an amount insufficient to warrant 
citation--that is, the level does not meet or exceed the CTV--MSHA will 
target that mine or area for additional sampling to ensure that dust 
controls are adequate.
(b) Abatement Sampling
    Under this proposed rule, MSHA would also assume responsibility for 
all abatement sampling. As recommended by the Dust Advisory Committee, 
MSHA would utilize single samples to demonstrate abatement. Since the 
criteria under which the effectiveness of ventilation plans are 
required to be verified are significantly more stringent than those for 
compliance sampling, MSHA does not anticipate issuing many citations to 
MMUs and sectional DAs.
    When a mine operator is cited for violation of the applicable dust 
standard, MSHA will require that approved respiratory equipment be made 
available to the affected miners in accordance with existing Sec.  
70.300 of this part. The mine operator also will be required to review 
the dust control practices to identify the cause of the excessive dust 
concentration and correct any deficiencies within the abatement period 
fixed in the citation.
    The mine operator must notify the district manager of the 
corrective measures taken within 24 hours of implementation to enable 
MSHA to determine whether abatement or verification sampling should be 
scheduled. This determination will be based on the review of the 
information the mine operator provides and the latest inspection 
reports documenting the measured quantities of the dust control 
parameters that were in use at the time the citation was issued.
    If it is determined that the existing dust control parameters are 
likely to be adequate to maintain compliance, the district manager will 
initiate abatement sampling under Sec.  70.218. For example, if the 
operator believes that the overexposure was caused by improper work 
practices, the proper course of action would be to review these work 
practices with the affected miners rather than requiring the operator 
to upgrade the engineering or environmental controls. Since there was 
no need to change the plan parameters, MSHA would initiate abatement 
sampling in this particular case.
    If, on the other hand, the district manager determines that the 
dust control parameters may not maintain respirable dust levels at or 
below the

[[Page 10793]]

applicable dust standard, the mine operator will be notified to revise 
the dust-control portion of the mine ventilation plan as specified in 
this Part.
    When MSHA samples a MMU for abatement purposes, single samples will 
be collected from the working environment of the cited occupation and, 
if available, four other occupations that will include the DO. Like 
compliance sampling, abatement sampling will be conducted portal to 
portal, for the entire shift or 8 hours, which ever is less.
    When sampling DAs and outby occupations, MSHA will collect a 
similar single-shift abatement sample from the environment of the cited 
DA or occupation.
    A citation for excessive dust will be terminated when all valid 
abatement samples collected are at or below the applicable dust 
standard. The subsequent action form will clearly and fully describe 
the action taken to abate the violation. Mine operators may be required 
to revise the ventilation plan in accordance with Sec.  75.370(a)(2) of 
this title depending on the type of corrective measures taken to abate 
the violation. This includes, at a minimum, the actual dust control 
parameters that were in effect when MSHA sampled.
    If the district manager requires the mine operator to initiate the 
plan verification process under Sec.  70.206 of this part instead of 
abatement sampling, the citation for excessive dust will be terminated 
after a revised plan has been verified to be effective for the current 
mining conditions.
(c) Operator Verification Sampling and Quarterly Sampling
    Mine operators are required, under this proposed rule, to verify, 
through sampling, the effectiveness of the dust control parameters for 
each MMU prior to receiving MSHA approval of the mine ventilation plan. 
In addition, certain mine operators must sample quarterly each DO, any 
occupation required to wear a PAPR or using administrative controls, 
and any other occupation designated by the district manager. The 
purpose of the quarterly sampling is to evaluate the continued 
effectiveness of the approved dust control parameters. These provisions 
are discussed elsewhere in this proposed rule.
(d) Advantages of MSHA Compliance Sampling Over the Existing Program
    Under section 101(a)(9) of the Mine Act, no health standard 
promulgated under the Act shall reduce the protection afforded miners 
by an existing mandatory health standard. The joint promulgation of 
this proposed rule and the proposed single sample rule, would provide 
protection to miners from the debilitating effects of occupational 
respiratory disease by limiting their exposures to respirable coal mine 
dust and quartz dust on every shift:
    [sbull] Providing and maintaining a work environment free of 
excessive levels of respirable dust is essential for long-term health 
protection. While monitoring of the work environment provides an 
indication of how effective the existing dust control measures are, 
monitoring alone does not control dust levels. Requiring mine operators 
to implement and maintain dust control parameters which have been 
determined effective under typical mining conditions, will provide 
reasonable assurance that no miner will be overexposed on individual 
shifts.
    [sbull] Implementing single-shift sample determinations will more 
likely detect excessive dust concentrations and thus protect miners. 
Averaging samples taken on multiple shifts can mask overexposures on 
individual shifts. Although fewer shifts will be sampled under this 
proposed rule, MSHA believes the revised sampling methodology will 
provide a more accurate representation of dust conditions to which 
miners are exposed.
    [sbull] Under the existing operator sampling program, only the DO 
is sampled. Under the new sampling program, MSHA will sample multiple 
occupations on the same shift. As a result, MSHA will make several 
times as many compliance determinations as under the previous operator 
and MSHA sampling programs combined, providing a more comprehensive 
assessment of dust conditions to which miners are exposed.
    [sbull] Since MSHA will be conducting all compliance sampling, the 
Agency will be able to monitor the dust control parameters and work 
practices in effect during sampling. This will enable MSHA to determine 
the effectiveness of the mine operator's dust control program.
    [sbull] Unlike the current sampling program, which allows 
operators' control over when to sample and under what operating 
conditions, MSHA's visits for compliance sampling will be unannounced. 
As a result, all phases of the mining cycle are likely to be sampled 
eventually (i.e., construction activity, longwall start-up, turning 
crosscuts, etc.), and samples should be more representative of typical 
mining conditions.
    [sbull] The miners' representative will have walkaround rights 
during all MSHA sampling, thereby increasing miners' confidence in the 
dust sampling program.

B. Procedures for Setting the Applicable Dust Standard When Quartz Is 
Present

1. Proposed Procedures
    Consistent with MSHA's proposed rule to assume full responsibility 
for compliance sampling, the Agency also proposes to rely only on MSHA 
samples, i.e., compliance or abatement samples, as the basis for 
setting the applicable dust standard when quartz is present. As 
discussed below, while today's proposed rule would reduce the burden 
and cost on mine operators to take and submit optional samples, it 
would not diminish the advantages afforded operators under the current 
program. In particular, it continues to consider temporal variability 
associated with quartz determinations by averaging three MSHA samples 
collected on different shifts.
    MSHA believes that results under this revised process will be more 
representative of the quartz levels to which miners are exposed. Unlike 
the current process, which may cause a standard to be set based on the 
quartz content of an individual MSHA sample, three valid MSHA samples 
would be used to set a reduced standard under the revised procedures 
(64 FR 65671).\5\ Since, under the rules being proposed today, MSHA 
intends to frequently sample underground mines and surface mines, MSHA 
personnel will have no difficulty in collecting the required number of 
samples to arrive at the average quartz percentage. If initial sampling 
shows that miners may be exposed to excessive levels of quartz, MSHA 
intends to sample at a greater frequency to ensure that miners are 
being protected. This level of sampling should also allay any operator 
concerns regarding the collection of ``misleadingly high'' samples 
during atypical periods. MSHA also intends to begin reporting quartz 
levels to the nearest tenth of a percent. This will be more protective 
for the miner than the current truncation of results to a full 
percentage point.
---------------------------------------------------------------------------

    \5\ Unlike MSHA's objective in compliance sampling, the 
objective in measuring quartz content is to establish a reduced 
standard that will apply to all shifts. This enables an operator to 
design a ventilation plan that will be protective on every shift. 
Therefore, it is appropriate to estimate the quartz content by 
averaging quartz measurements obtained over an extended time period.
---------------------------------------------------------------------------

    Under the revised procedures, when an MSHA sample contains more 
than five percent quartz, the agency will average the percent of quartz 
present in three most recent MSHA respirable coal mine dust samples to 
set the applicable

[[Page 10794]]

dust standard. If a MMU, DA, Designated Work Position (DWP) at an 
underground mine, or Part 90 miner is already on a reduced standard, a 
new applicable dust standard will be established by averaging the 
results of the first two MSHA samples, taken under the revised 
procedures, with the quartz percentage associated with the reduced 
standard in effect. If fewer than two MSHA samples are taken, the 
existing reduced standard will continue to remain in effect.
    Assume a MMU is on a 1.0 mg/m\3\ standard (10 percent quartz). If 
the first MSHA sample contains 7.2 percent of quartz, the existing 
standard of 1.0 mg/m\3\ would continue to remain in effect. If, 
however, the next sample contains 16.1 percent, the average quartz 
percentage would be 11.1 percent [(10.0% + 7.2% + 16.1%) 3 = 11.1%], 
resulting in a 0.9 mg/m\3\-standard (10 11.1% = 0.9 mg/m\3\). For any 
MMU, DA, DWP, or Part 90 miner not on a reduced standard, MSHA will 
collect and analyze three samples for quartz to determine if a reduced 
standard is warranted.
    Under the revised procedures, if the newly-established standard is 
lower than the one in effect, the new standard will become effective 
seven days after the date of the notice informing the mine operator of 
the change in the applicable dust standard. However, if it is higher 
than the current standard, the newly-established applicable dust 
standard will become effective on the date of the notice.
    As published elsewhere in today's Federal Register, MSHA is 
proposing to take enforcement actions on the basis of single-shift 
sample measurements. For entities on reduced standards, MSHA would 
delay enforcement action until the sample is analyzed for quartz. If an 
exposure measurement significantly exceeds the existing standard and 
the quartz content of that sample would cause the standard to be 
lowered below the existing reduced standard, the operator will be cited 
for violation of the applicable dust standard currently in effect. On 
the other hand, if the quartz content of the sample would cause the 
applicable dust standard and the corresponding citation threshold value 
(CTV) to increase so that the single-shift sample measurement would no 
longer indicate noncompliance, no citation will be issued. This is 
illustrated by way of the following example.
    For example, suppose that the MMU is on a 1.3 mg/m\3\ standard and 
a single-shift sample measurement of 1.6 mg/m\3\ is obtained. Since 
this measurement exceeds the CTV value, the operator is in violation of 
the standard. However, analysis of the DO sample shows that the sample 
contained 5.6 percent quartz which, if averaged with the previous two 
MSHA quartz levels, would result in a 1.7-mg/m\3\ standard. This 
indicates that the quartz level in the environment of the DO has 
changed, indicating that the current standard is no longer valid. 
Therefore, since the original measurement of 1.6 mg/m\3\ is less than 
the 1.7-mg/m\3\ standard that could have been in effect for the shift 
sampled, a citation would not be issued.
    Since MSHA samples are viewed to be more representative of the 
respirable dust concentration to which miners are exposed, MSHA is 
proposing to revise section 70.101 to clarify that the Secretary will 
determine the quartz level by sampling. Operator samples would no 
longer be submitted to determine the applicable dust standard. It is 
our belief that the procedures being proposed today for setting reduced 
standards will be more protective for the miners than those in effect 
at this time. The revised approach provides for stringent monitoring of 
miners' exposure to quartz which is consistent with the Dust Advisory 
Committee's recommendation that MSHA increase surveillance and reduce 
exposure to this serious health hazard.
    As under the current program, if operating conditions change 
following establishment of a lowered applicable dust standard and 
affect the level of quartz in the working environment, MSHA intends 
that mine operators or miners' representatives will be able to request 
MSHA to conduct a quartz reevaluation.
2. Validity of Averaging Percentages
    The average quartz percentage that MSHA intends to use to set the 
applicable dust standard for a particular sampling location or area of 
a mine would be determined in accordance with accepted mathematical 
procedures for arriving at an average value from a set of values (i.e., 
adding together the individual quartz percentages and dividing by the 
number of analyses that are in the set). MSHA believes that this is the 
most appropriate method to use.
    One commenter who responded to a draft 1999 program policy letter 
(November 23, 1999, 64 FR 65671) concerning this issue contended that 
MSHA's approach of arriving at the average quartz percentage was 
mathematically incorrect. This commenter recommended that, to more 
accurately reflect the true quartz concentration, the average quartz 
percentage be calculated by dividing total mass of quartz in micrograms 
by the total mass of dust collected (based on three samples in the 
example submitted). In the commenter's example, the average percentage 
obtained using MSHA's proposed averaging method was larger than that 
obtained using the commenter's approach.
    The following two scenarios in Table III-1 clearly demonstrate that 
MSHA's intended averaging method does not always result in a larger 
average quartz percentage value.

[[Page 10795]]

[GRAPHIC] [TIFF OMITTED] TP06MR03.000

    These examples show that for situations where MSHA would have 
determined a quartz percentage of 8.0 percent, the commenter's method 
would yield 9.2 percent in one case and 7.7 percent in the other.

C. Respirable Dust Control Program for Underground Coal Mines

    The primary focus of the underground coal mine respirable dust 
program is to limit the concentration of respirable dust to which 
miners are exposed in the work environment. To ensure that miners are 
not being exposed to excessive concentrations of respirable dust, 
current regulations require mine operators to:
    [sbull] Design a mine ventilation plan that effectively controls 
respirable dust under typical mining conditions;
    [sbull] Implement the plan's dust control parameters when approved 
by MSHA before commencing production;
    [sbull] Maintain the dust control parameters specified in the 
approved plan and monitor their function and operation through required 
on-shift examinations; and
    [sbull] Evaluate the effectiveness of dust control parameters with 
bimonthly samples in order to provide reasonable assurance that such 
parameters continue to function as intended.
    In addition, each plan must be suitable to the conditions and 
mining system in use at the mine. These plans provide detailed 
requirements for the protection of miners by specifying engineering 
controls. These engineering controls may include:
    [sbull] The quantity and the velocity of the air current used to 
ventilate the MMU;
    [sbull] The number, type, and location of water sprays;
    [sbull] The pressure and quantity of water delivered by the sprays; 
and
    [sbull] Additional environmental controls, such as dust scrubbers 
or devices which collect mine air and filter out dust particles.
    Plans also contain procedures for maintenance of dust control 
equipment used on the mining machine and roof bolter. Mine operators 
frequently do not describe all dust controls in use at the mine. If 
such information is not included in the plan, it is impossible for MSHA 
to enforce those provisions or to determine if the ventilation plan 
provisions as approved are adequate to protect miners from 
overexposure.
    When an operator submits a proposed mine ventilation plan or 
revision in accordance with Sec.  75.370, the MSHA district office 
reviews it for completeness and adequacy. The district manager will 
approve the plan if it meets MSHA requirements, and he or she is 
confident that the dust control parameters specified will have a 
reasonable likelihood of maintaining dust concentrations within the 
allowable limits. Most proposed plans or revisions are approved 
immediately, or tentatively approved, based on engineering judgement, 
or experience, or both, until they are assessed by MSHA sampling or, to 
a lesser extent and only under certain circumstances, by mine operator 
bimonthly sampling. Generally, MSHA takes samples within 60 days of 
plan approval. Current regulations prohibit a mine operator from 
initiating any mining activity without an approved ventilation plan. 
MSHA allows operators to commence mining by granting tentative 
approval. However, under the existing process, plans may be implemented 
which are later determined to be inadequate under typical mining 
conditions.
1. Proposed Procedures for Evaluating, Approving, and Monitoring 
Ventilation Plan Requirements
    The dust control portion of the mine ventilation plan is the key 
element of an operator's strategy to control respirable dust in the 
work environment, thereby protecting miners. In recognition of this, 
MSHA is proposing to make a number of changes to the process for 
evaluating, approving, and monitoring mine ventilation plans, many of 
which are based on the Dust Advisory Committee's recommendations. These 
are addressed in detail under proposed Sec. Sec.  70.201 through 70.220 
of the preamble.
    Consistent with the Dust Advisory Committee recommendations, MSHA 
is proposing to add provisions to verify the effectiveness of the 
ventilation plan in controlling dust, at a production level which will 
demonstrate the plan's effectiveness under typical operating 
conditions. Dust control parameters and production associated with 
samples on a given shift would be recorded in order to demonstrate that 
parameters specified in the ventilation plan continue to be effective 
in controlling respirable dust.
    This proposed rule requires a ventilation plan to include all 
engineering or environmental controls necessary for maintaining dust 
concentrations at acceptable levels. A plan must also include any 
specific work practices or other means used to supplement these 
controls in order to minimize the dust exposure of individual miners. 
Unlike plans under the existing program, mine operators will have to 
identify all measures necessary for achieving continuous

[[Page 10796]]

compliance with the applicable dust standard in the plan.
    MSHA would require mine operators to include information on the 
length of each normal production shift in Sec.  75.371(f) and to 
specify the VPL, as defined in Sec.  70.2, in every ventilation plan. 
The VPL is the tenth highest production level recorded in the most 
recent 30 production shifts. This value will represent the minimum 
production level at which effectiveness of the plan must be 
demonstrated.
    MSHA believes that the current production criteria used to evaluate 
plan effectiveness may not adequately represent typical conditions 
under which miners work. Requiring that plans be verified at or above 
the VPL will provide assurance that excessive dust concentrations will 
be avoided, even on shifts with higher-than-average production. This is 
far more protective of miners than the current practice of evaluating 
plan adequacy based on MSHA samples taken when production can be as low 
as 60 percent of the average production.
    Some commenters on the earlier proposed rule expressed confusion 
about the relative magnitude of the VPL, compared to average production 
or other possible production criteria. Figure 1 shows a typical 
distribution of 30 shift production levels recorded at a longwall MMU. 
As illustrated by this example, the VPL, defined as the 10th highest 
production achieved during 30 shifts, generally exceeds the average 
production by a substantial amount.
BILLING CODE 4510-43-P

[[Page 10797]]

[GRAPHIC] [TIFF OMITTED] TP06MR03.001

BILLING CODE 4510-43-C
    MSHA proposes to require mine operators to maintain records of the 
amount of material produced by each MMU during each shift. This will 
enable operators to establish the VPL. Because verification of a plan's 
effectiveness is conditioned on the VPL, these records are necessary to 
ensure that the VPL continues to represent typical production levels. 
Although a VPL must be included in the ventilation plan, MSHA will not 
cite mine operators for producing at levels exceeding the VPL.
    MSHA considers the VPL to be a plan design criteria, not a minimum 
plan parameter that must be in effect on every shift. The Agency would 
expect production on a MMU to exceed the VPL on about 33 percent of all 
production shifts. If the district manager determines that an 
operator's actual production exceeds the VPL on more than 33 percent of 
the production shifts over a six-month period and the operator or MSHA 
samples exceed the applicable standard, the district manager may 
require that the adequacy of the plan parameters be verified under

[[Page 10798]]

different operating conditions of production.
    Under the proposed plan verification procedures, mine operators 
will be required to verify through sampling the effectiveness of the 
dust controls specified in the ventilation plan prior to approval of 
that plan by the district manager. Sampling would occur when production 
is at or above the VPL specified in the plan and using only those 
control parameters and other measures listed in the plan. The sampling 
pumps must be turned on upon arrival on the MMU and remain operational 
during the entire production shift. The pumps must be turned off upon 
leaving the MMU. Samples would be collected on multiple occupations 
which are specified in proposed Sec.  70.206. All verification samples 
must be transmitted to MSHA. However, no citations would be issued to 
mine operators if the verification sample results show that the 
applicable dust standard has been exceeded. Operators would be cited 
only if they fail to take steps to determine the cause and take 
corrective action to eliminate the overexposure. The agency would 
approve a plan only when a sufficient number of verification samples 
demonstrate, at a high level of confidence, that the plan is effective 
at production levels at or above the VPL.
    Unlike the existing program, this proposed rule would allow certain 
longwall and other operations to use either approved PAPRs, 
administrative controls, or both, to supplement engineering or 
environmental controls if the mine operator is unable to verify the 
ventilation plan. This will be permitted only after the Administrator 
for Coal Mine Safety and Health determines that the operator has 
exhausted all feasible engineering or environmental controls. District 
managers also may allow mine operators to use PAPRs to achieve 
compliance with the applicable dust standard when unusual operating 
conditions are encountered briefly and intermittently and the operator 
believes that the approved plan parameters will not adequately protect 
all miners from overexposure. The period of time when PAPRs may be used 
cannot exceed 30 calendar days under this proposed rule. An example of 
when such approval may be granted is when an operator periodically must 
mine through rock strata with high quartz content.
    Finally, under this proposed rule, mine operators also would be 
required to sample each DO and occupation using PAPRs or administrative 
controls at least once every three months to evaluate the continued 
adequacy of the approved plan parameters. As with verification samples, 
operators would only be cited if they fail to take corrective action to 
eliminate any overexposure identified through such sampling.

D. Hierarchy of Dust Controls

1. Primacy of Engineering Controls
    Consistent with the Mine Act, engineering or environmental controls 
have been the principal method used for preventing or minimizing 
miners' exposure to both primary and secondary dust sources in the 
workplace over the past 30 years. Engineering controls that are able to 
manage the amount of dust throughout the work environment give 
reasonable assurance that all miners in the area will be adequately 
protected. Well-designed engineering or environmental controls provide 
consistent and reliable protection to all workers because they are not 
dependent upon constant human supervision or intervention, except for 
the periodic checks, to ensure that they are functioning as intended. 
Under this proposed rule, operators would be required to utilize, on 
each production shift, all engineering or environmental controls as 
specified in their mine ventilation plans. These controls will maintain 
concentrations of respirable dust in the work environment of MMUs at or 
below the applicable dust standard. Engineering or environmental 
controls include all methods that control the level of respirable dust 
by reducing dust generation (e.g., machine parameters) or by 
suppressing (e.g., water sprays, wetting agents, foams, water infusion, 
etc.), diluting (e.g., ventilation), capturing (e.g., dust collectors), 
or diverting (e.g., shearer clearer, passive barriers, etc.) the dust 
being generated by the mining process.
    The importance of using engineering or environmental controls was 
recognized by the Dust Advisory Committee and by NIOSH in Occupational 
Exposure to Respirable Coal Mine Dust (NIOSH, 1995). NIOSH recommended 
that such controls must continue to be relied upon as the primary means 
of protecting coal miners. The primacy of engineering or environmental 
controls would be preserved under this proposed rule. The proposed rule 
requires a mine operator to utilize all feasible engineering or 
environmental controls, specified in the approved ventilation plan, to 
reduce concentrations of respirable dust to a level at or below the 
applicable dust standard.
2. Administrative Controls
    Administrative controls are another method of avoiding 
overexposure. Administrative controls refer to work practices that 
reduce a miner's daily exposure to respirable dust hazards by altering 
the way in which work is performed. They consist of such actions as 
rotation of miners to areas having lower dust concentrations, 
rescheduling of tasks, and modifying work activities. The Task Group 
found that administrative controls were used increasingly, even when it 
was feasible to implement additional engineering or environmental 
controls. The use of administrative controls was found to be increasing 
at mines employing longwall mining systems.
    The most frequent administrative control in use consisted of 
restricting the activities of miners required to work downwind of the 
longwall shearer operator, the occupation designated as 044 by MSHA. 
This particular form of administrative control was in use at some of 
the 51 longwall MMUs that were operating on October 28, 1999. MSHA has 
observed the use of this particular administrative control, even after 
changing the location of the DO from the 044 to the 060 occupation--the 
miner who works nearest the return air-side of the longwall working 
face. Unlike engineering or environmental controls, to be effective, 
administrative controls rely on the ability of miners to follow 
specified procedures. However, difficulty in ensuring that miners 
adhere to the administrative controls, labor/management agreements, and 
limitations on the number of qualified miners capable of handling 
specific tasks may limit the use and effectiveness of such controls.
    The Dust Advisory Committee Report stated that the use of 
administrative controls does not reduce the operator's responsibility 
to maintain ambient dust levels in active workings at or below the 
applicable dust standard. However, the Dust Advisory Committee noted 
that ``while not a substitute for engineering controls, administrative 
controls, which restrict the amount of time that miners spend in an 
area with uniform exposure level, can result in lower personal 
exposures (MSHA, 1996).''
3. Limitations of Engineering Controls
    It is MSHA's position that technology is generally available to 
control respirable dust to, or below, the applicable dust standard at 
MMUs employing continuous and conventional methods of mining. However, 
where unusual or adverse conditions are encountered it is possible that 
available

[[Page 10799]]

controls may be inadequate to continuously protect all miners from 
overexposure. This is most likely to occur in areas where high levels 
of quartz are encountered that may result in the setting of lowered 
standards on a MMU.
    However, MSHA recognizes that, unlike other mining systems, 
longwall MMUs may have acute dust problems. These problems can be 
caused by the face-ventilation airstream carrying the shearer-generated 
dust over the miners working along the face downwind of the longwall 
shearer operator (occupation code 044). This makes it more difficult to 
control the work environment downwind of the longwall shearer operator 
on a consistent basis.
    Improvements in dust control technology have not kept pace with 
increases in production technology associated with high-production 
longwall MMUs. Average longwall shift production reported during 
bimonthly sampling has increased more than six-fold since 1980, from 
approximately 890 tons per shift (tps) to 5,500 tps in 2002. In fact, 
49 percent of the shifts sampled averaged 4,000 to 8,000 tps, while 
approximately 8 percent of the shifts exceeded 8,000 tps. A major 
milestone in mining production was achieved in 1997 when a single 
longwall mine produced more than 1 million tons of coal in a single 
month (Fiscor, 1998).
    Unfortunately, as more coal is mined, greater quantities of 
respirable dust are generated. The increase in longwall production 
levels has resulted in the generation of far more dust which must be 
controlled (Webster, et al., 1990; Haney, et al., 1993; O'Green, 1994). 
According to published literature, several thousand milligrams of 
respirable dust per ton of coal cut can be formed and liberated during 
the cutting process (National Research Council, 1980). Of course, the 
quantity of respirable dust produced by the cutting process can vary 
greatly, depending on the type of coal, its moisture content, the 
amount of rock bands in the coal, sharpness of the cutting bits, the 
particular mining machine, and many other factors. Although a 
considerable amount of respirable dust is formed by the cutting 
operation, not all of it becomes airborne. Nevertheless, given the 
amount of dust that is produced per ton of coal mined, a larger 
quantity of respirable dust would be generated and released to the mine 
environment from cutting 8,000 tons of coal than from cutting 4,000 
tons. Currently, an operator is not required to produce, on a sampled 
shift, more than 50 percent of the average production reported during 
the last bimonthly sampling period. Therefore, dust concentrations on 
sampled shifts may be substantially lower than what is typical on 
nonsampled shifts.
    While significant efforts have been made to implement available 
control technology, no significant new advancements in longwall dust 
control technology have been reported since 1989 (U.S. Bureau of Mines, 
undated). From 1989 to 2002 (Jan.-Sept.), the percentage of operators' 
longwall DO samples with concentrations of 2.1 mg/m3 or 
higher dropped from 22 percent to 14 percent, reflecting the impact of 
implementing the pre-1990 advances in longwall control technology. 
Although this represents a significant improvement, especially in view 
of the six-fold increase in average shift production, the 2002 data 
suggests that miners continue to be overexposed on a significant number 
of shifts.
    Over the past ten years, MSHA and the former U.S. Bureau of Mines, 
now part of NIOSH, have made unsuccessful efforts to conduct a joint 
research program that would evaluate the effectiveness of available 
longwall dust control technology. The objective of such research would 
have been to quantify the effects of employing all state-of-the-art 
dust control technology available for a longwall operation. 
Unfortunately, the two agencies have been unsuccessful in finding an 
industry partner to participate.
    MSHA has worked with mine operators on an individual basis to 
determine the effectiveness and feasibility of existing and additional 
respirable dust controls on a particular longwall. However, the design 
and goals of those studies were neither intended nor sufficient to meet 
MSHA's broader research objective. Rather, the scope of those studies 
was to evaluate the effectiveness of control technology that both MSHA 
and the mine operator agreed were applicable to that one particular 
longwall MMU. The objective of the cooperative research program that 
MSHA and the Bureau of Mines were attempting to conduct, was to 
establish the combined efficiency of the various control technologies 
that the Bureau of Mines had developed through their ongoing dust 
control research program.
    However, even though no such study has been conducted, based on our 
experience, MSHA's position remains that feasible engineering or 
environmental controls exist for maintaining dust exposures at or below 
the applicable dust standard, for most, if not at all longwall 
operations. MSHA believes that the plan verification provision 
contained in this proposed rule will foster further improvements in the 
design and quality of mine ventilation plans for longwall MMUs.
4. Respiratory Protection
    While the Mine Act provides that operators ``make available'' 
approved respirators to miners during periods of noncompliance, when 
miners may be overexposed, the Act specifically prohibits using such 
devices as a substitute for environmental controls in the active 
workings of the mine. As previously discussed elsewhere in the 
preamble, this is because environmental or engineering controls are 
reliable, provide consistent levels of protection to large number of 
miners, allow for predictable performance levels, can be monitored 
continually and inexpensively, and can remove harmful levels of 
respirable coal mine dust from the workplace. MSHA recognizes that 
approved respirators, such as the powered air-purifying type (e.g., 
Racal[reg] Airstream helmet or air helmet),\6\ can be effectively used 
as an interim method of protecting miners from respirable dust hazards 
when properly selected, used, and maintained. Although a respirator may 
achieve satisfactory air quality in the miner's breathing zone when 
used in a good respirator program, their use will not achieve the 
intent of the Act, which is to control the level of respirable coal 
mine dust in the mine atmosphere in the active workings at or below 
specific limits. Accordingly, consistent with the intent of the Act and 
general industrial hygiene practice, it has been MSHA's long-
established practice to rely on the strict adherence to a hierarchy of 
controls that prefers engineering controls over dependence on 
supplementary control measures (e.g., respirators, work practices or 
both) to achieve compliance with the applicable dust standard.
    Nevertheless, the mining industry has urged MSHA over the years to 
accept the use of powered air-purifying respirators (PAPRs) or air 
helmets as an alternative method of complying with the applicable dust 
standard when engineering controls did not adequately control 
respirable exposure or were not feasible. Most recently, Energy West 
Mining Company (Energy West) petitioned the Secretary of Labor:

    \6\ References to specific equipment, trade names or 
manufacturers does not imply endorsement by MSHA.
---------------------------------------------------------------------------

[t]o amend the mandatory health standards for underground coal mines 
contained in the Secretary's regulations at 30 CFR part 70 in order 
to allow the use of airstream helmets or other types of powered air-
purifying respirators (PAPRs) approved by the National Institute for 
Occupational Safety and Health (NIOSH) as a supplemental means of

[[Page 10800]]

compliance with the respirable dust standards of subpart B of part 
---------------------------------------------------------------------------
70. (Energy West, September 1997).

Energy West contended that PAPRs are necessary as a supplemental means 
of controlling respirable dust because even the most diligent 
application of feasible engineering or environmental controls could not 
always prevent overexposure. This proposed rule responds to Energy 
West's petition for rulemaking.
    Although, as stated above and elsewhere in the preamble, the Agency 
does not believe that supplementary controls are as effective or as 
safe as engineering controls, MSHA believes, on balance, that under 
certain circumstances reliance upon the limited use of such measures is 
appropriate. Accordingly, MSHA is proposing to permit the limited use 
of either approved PAPRs, administrative controls, or a combination of 
both, for compliance purposes, in those circumstances where further 
reduction of dust levels cannot be reasonably achieved using all 
feasible engineering controls. In these situations, the burden of proof 
of infeasibility is appropriately placed on the operator. Also, as 
provided for under proposed Sec.  70.212, MSHA recognizes that the use 
of PAPRs as a supplementary control may be appropriate on an 
intermittent basis when unusual operating conditions are encountered 
that adversely impact the ability of the previously verified plan 
parameters to effectively control respirable dust under prevailing 
conditions. MSHA will permit the use of PAPRs for a period not 
exceeding 30 calendar days if the operator demonstrates that the 
particular circumstances that necessitate the use of PAPRs occur only 
intermittently and are beyond the control of the operator.
    While the conditions under which MSHA would permit supplementary 
controls to be used introduces an added element of complexity to the 
proposed standard, the Agency believes that it will provide operators 
the flexibility to select the most appropriate option for supplementing 
the engineering controls which best meet the needs of the miners under 
the prevailing operating conditions.
    MSHA believes that the use of these supplementary control measures, 
under the conditions of use set forth in the proposed rule, will 
enhance the level of health protection for miners by preventing 
overexposures on all shifts when engineering controls cannot achieve 
the necessary reduction to or below the applicable dust standard. The 
combination of engineering and supplementary controls will provide 
reliable and effective exposure control when used in accordance with 
the approved plan provisions. This proposed rule, which provides for 
expanded use of supplementary controls under limited circumstances to 
protect individual miners, is not a departure from the Agency's long-
standing practice of relying on engineering controls to achieve 
compliance, since these measures would not be used as a substitute or 
replacement for engineering control measures in the active workings. 
Rather, it is a recognition that, in those limited instances where 
supplementary controls may be used, engineering controls alone may not 
protect some miners from overexposure.
a. Selection of Respirators: Powered Air-Purifying Respirators (PAPR)
    By choice, underground coal miners wear various styles of 
respirators to protect themselves from exposure to respirable coal mine 
dust including: disposable filtering facepieces, tight-fitting 
elastomeric masks, and PAPRs. Currently, over 50 percent of the 
operating longwall mines have miners who have chosen to wear PAPRs 
(MSHA, Longwall Summary, January, 1999) for added protection.
    The Racal[reg] Airstream, or air helmet as referred to by miners, 
is a type of loose-fitting PAPR which has long been the respirator of 
choice in underground coal mines. Due to the weight of the device, its 
use has generally been limited to mines with coal seam heights 
exceeding six feet. The functional and physical characteristics of air 
helmets, as described below, make them especially well-suited to 
underground coal mining conditions. Accordingly, MSHA has chosen PAPRs 
as the type of respirator to be used when such devices are approved 
under this proposed rule.
    The air helmet has been in use in underground coal mines since the 
late 1970s. Developed primarily for mining use by the Safety in Mines 
Research Establishment (SMRE) in England, this respirator combines 
face, head, and respiratory protection in a single convenient unit. The 
support hardware, which provides the filtered air, is enclosed within 
the air helmet. Power for the system is provided by a belt-mounted 
battery. Mine air enters the helmet through a rear entrance port, 
passes through a pre-filter assembly that removes the coarse material, 
and then passes through the fan and into a final-filter assembly that 
is located between the head of the wearer and the outer helmet shield. 
The filtered air then sweeps down across the wearer's face, behind the 
face-shield visor, imposing minimal breathing resistance, and exits at 
the chin. A partial seal between the visor (inlet covering) and the 
face is accomplished using a flexible medium which contours to the 
wearer's neck and face. The original air helmet has undergone numerous 
design improvements since it was first introduced in British coal 
mines. The unit is now produced by the Minnesota Mining and 
Manufacturing Company (3M) (3MTM Helmet-Mounted 
AirstreamTM series).
    Unlike other styles of PAPRs (e.g., hoods) and negative pressure, 
tight-fitting respirators, the air helmet is better able to provide 
various types of required personal protective equipment in an efficient 
package. For example, in addition to protecting the lungs, the helmet 
and visor (the inlet covering) of a PAPR can simultaneously protect the 
face and head from high-velocity nuisance dust, spray, and small pieces 
of coal from the cutting drums and face. PAPRs do not require fit-
testing, unlike tight-fitting respirators.
    By definition, for PAPRs to be approved for use under this proposed 
rule, the visor must form a partial seal with the face, limiting entry 
of unfiltered mine air. Because this style of respirator does not have 
a tight-fitting facepiece, miners are not required to be clean shaven 
in order to wear this respirator correctly. MSHA's allowance of facial 
hair with this style of PAPR is also consistent with the Occupational 
Safety and Health Administration's (OSHA) regulation that facial hair 
prohibition applies only to tight-fitting respirators (29 CFR 1910.134 
(g)(1)(i)(A) as discussed in 63 FR 1152). MSHA recognizes that there 
may be facial conditions which may prevent the proper fit of a PAPR. 
However, a well-designed respirator protection program should identify 
and address any extreme facial conditions, including excessive facial 
hair, which prevent the partial seal of the inlet covering and the face 
as intended, and thereby compromise the efficacy of the PAPR. For 
example, a miner could have exceptionally bushy sideburns which prevent 
the inlet covering from forming an appropriate partial seal with the 
face, and leave a significant gap between the inlet covering (visor) 
and chin. This situation would have to be rectified in order for the 
PAPR to be worn properly.
    Greenough (1978) summarized limitations of other styles of 
respirators as follows:

    [T]he objections to conventional face-mask respirators arise 
primarily from the mask being clamped to the wearer's face, often 
causing irritation and soreness: also the breathing resistance, 
though small, can affect the wearer's capacity to work over long

[[Page 10801]]

periods (Johnson, 1976). Speech is impeded and if the respirator 
harness fits under the wearer's safety helmet it is necessary to 
remove the helmet when replacing the respirator.

    Greenough's description illustrates how other styles of respirators 
are less compatible with the other safety requirements for miners, as 
well as miners' comfort, and their need to communicate. It would be 
more difficult for a miner to perform his/her job effectively and 
communicate with fellow workers, wearing a tight-fitting respirator 
their entire work shift. Voice transmission through a tight-fitting 
respirator can be difficult, annoying and fatiguing. In addition, 
movement of the jaw in speaking can cause leakage, thereby reducing the 
efficiency of the respirator and decreasing the protection afforded the 
wearer. While voice communication is somewhat easier with a PAPR than 
with other respirator styles, the face shield is generally raised to 
communicate. Also skin irritation can result from wearing a tight-
fitting respirator in hot, humid conditions. Tight-fitting respirators 
have straps which go across the crown and back of a miner's head which 
is under a miner's helmet (i.e., hard hat). Because miners are required 
to wear hard hats at all times while in the mine (30 CFR 75.1720(d)), 
each time a miner needs to break the seal of a tight-fitting 
respirator, to eat, or to speak, or to relieve the discomfort of the 
seal, he/she would have to remove the hard hat. Similarly, each time a 
miner would need to put a tight-fitting respirator back on he/she would 
have to remove their hard hat. It should be noted that both tight-
fitting elastomeric respirators and disposable facepieces, if worn 
correctly, would require the wearer to be clean shaven. A large 
proportion of miners have a tendency to wear facial hair, especially 
during the fall and winter season.
    The unique qualities of the PAPR identified within this proposed 
rule are such that it could fall into either the helmet or loose-
fitting facepiece categories. ANSI defines a loose-fitting PAPR with a 
helmet to be ``a hood that offers head protection against impact and 
penetration (ANSI, 1988).'' ANSI defines a loose-fitting PAPR with a 
loose-fitting facepiece as ``A respirator inlet covering that is 
designed to form a partial seal with the face, does not cover the neck 
and shoulders, and may offer head protection against impact and 
penetration (Ibid.).'' In this proposed rule, a powered air-purifying 
respirator (PAPR) is defined as an air-purifying respirator that uses a 
blower to force ambient air through the air-purifying elements to the 
inlet covering, which provides a partial seal with the face. This 
respirator must be approved by NIOSH under 42 CFR part 84 and by MSHA 
under 30 CFR 18 and offer head and face protection in compliance with 
30 CFR 75.1720(a)and(d).
    A current list of equipment, including PAPRs, approved under 30 CFR 
18 can be obtained from MSHA's Approval and Certification Center on the 
internet at http://www.msha.gov/TECHSUPP/ACC/lists/18instrm.pdf. A 
searchable index of approved respirators is available from NIOSH at 
http://www2.cdc.gov/drds/cel/cel_form.asp. As of 2002, the 3M 
Airstream Air-Purifying Helmet (MSHA Approval 2G-3143, originally 
issued to Racal 3/29/1979), was the only approved PAPR model suitable 
for use under this proposed rule.
b. PAPR Protection Program
    In an underground coal mine, the degree of respiratory protection 
that a properly functioning PAPR will provide the wearer is a function 
of the type and condition of the air-purifying medium used to filter 
out the respirable dust particles from the mine air, the workplace 
environment (i.e., nature and concentration of the respirable coal mine 
dust), the work activity of the wearer in that environment, how the 
wearer uses the device (i.e., how often is the visor raised during the 
shift), and the care and maintenance of the PAPR's functional 
components and power source. These parameters are required to be 
addressed in the approved PAPR protection program (see example in 
Appendix B).
    In 1998, to increase the efficiency of the filtering medium used in 
PAPRs, NIOSH began requiring PAPRs to be equipped with a high 
efficiency particulate air (HEPA) filter. This change introduced a 
denser medium to filter the air, providing an extra margin of safety at 
all levels of respirable coal mine and quartz dust exposure. However, 
as a result of this change, the PAPR's average airflow dropped from 
about 9 cubic feet per minute (cfm) to 7 (cfm). While the current 
airflow still exceeds the required minimum airflow of 6 cfm (42 CFR 
84.1152(b)), the drop in airflow reduced the level of comfort the PAPR 
provides to the miner.
    MSHA realizes that miners' comfort with a particular respirator is 
an important determinant to miners' proper use of it. Several previous 
commenters testified that PAPRs were not being used as approved.\7\ 
Many of these examples related to reports that visors were fogging. 
These commenters attributed the fogging problem to NIOSH's recent (mid-
1998) improvement in the filtering medium for PAPRs. One commenter 
testified:

    \7\ NIOSH requirements for PAPR performance, including airflow 
are specified in 42 CFR subpart kk. Although Sec.  84.1136 specifies 
that facepieces, hoods, and helmets shall be designed and 
constructed to provide adequate vision which is not distorted by the 
eyepiece, NIOSH does not have requirements for a visor's 
predisposition to fogging.
---------------------------------------------------------------------------

    I would have to answer honestly and say they [PAPRs] are being 
used in a modified condition. Miners some, you know, have typically 
removed the shroud * * * [miners] raise the face piece to 
communicate and so on * * *. We've had that [fogging of the visor] 
problem recently, * * * since we've been required [by NIOSH] to use 
the new version of the filter [the HEPA filter]. There has been what 
seems to be reduced flow in the unit and that has also resulted in 
more fogging. And we've worked real hard to try to--[work] with 3-M 
to try to resolve that.

MSHA's experience has shown that fogging of PAPRs has been an 
intermittent problem since the introduction of PAPRs in underground 
mines. This is due to the inclement conditions of underground mining 
such as: High humidity, fluctuation in temperature, and physical 
exertion by miners.
    Some miners indicated that they had to replace the HEPA filters 
with socks to increase the PAPR airflow. Using socks in lieu of 
required filters is unacceptable. This one example of PAPRs being used 
outside the manufacturer's recommendations and the requirements of an 
approved respiratory protection program. Various approved remedies are 
available to control fogging of visors including: intermittent wiping 
down of the visor, ``anti-fogging'' visors, application of anti-fogging 
sprays, and the use of a new visor design with an anti-fog impregnate 
baked directly into the visor. A properly functioning respiratory 
protection program would address this issue, with respect to the 
appropriate selection and maintenance of a respirator.
    MSHA recognizes that for a PAPR protection program to be effective, 
the miner must be properly trained to wear the respirator, to know why 
the respirator is needed, and to understand the limitations of the 
respirator. Appendix B contains a model PAPR protection program to 
assist an operator in developing a mine-specific program in accordance 
with the provisions of the American National Standards Institute's 
``Practices for Respiratory Protection ANSI Z88.2-1969'' as required by 
30 CFR 72.710. Additionally, mine management must regularly conduct 
reviews to ensure continued effectiveness of the PAPR protection

[[Page 10802]]

program. Under this proposed rule an operator will not be permitted to 
use PAPRs as a supplementary control without an MSHA approved 
respiratory protection program which meets the requirements of Sec.  
72.710 and incorporates the information required by proposed Sec.  
70.210(a)(2).
c. PAPR Protection Factor
    The degree of workplace respiratory protection provided to the 
wearer by a properly functioning PAPR when correctly worn and used 
depends on the unit's ability to prevent the contaminant from entering 
the wearer's breathing zone. In general, the protection factor (PF) 
expresses PAPR performance as the ratio of the respirable dust 
concentration outside the respirator facepiece to the concentration 
inside the facepiece. It reflects the effectiveness of a respirator 
used in conjunction with a good respirator protection program. For 
example, a PF of 4 means that the particular respirator will reduce the 
concentration of respirable dust actually breathed to one forth of the 
concentration outside the respirator.
    In terms of worker health, there are various forms of the PF. One 
form is the assigned protection factor (APF). Terry Spear, et al., 
2000, defined an APF as follows:

    APF is a special application of the general protection factor 
concept, defined as a measure of the minimum nominal anticipated 
workplace level of respiratory protection that would be provided by 
a properly functioning respirator or class of respirators to a high 
percentage (usually 95% or more) of properly fitted and trained 
users * * *. The maximum specified use concentration for a 
respirator is generally determined by multiplying the exposure limit 
for the contaminant by the protection factor assigned to a specific 
class of respirator.

    In the NIOSH Respirator Decision Logic (May 1987), based on 
simulated laboratory tests and some workplace protection tests (none of 
which replicated conditions in underground coal mines), NIOSH assigned, 
helmeted PAPRs, properly worn, a protection factor (APF) of 25. NIOSH 
made the following cautionary statement:

    Despite the fact that some of the PF's [APFs] have a statistical 
basis, they are still only estimates of the approximate level of 
protection. It must not be assumed that the numerical values of the 
APF's presented in this decision logic represent the absolute 
minimum level of protection that would be achieved for all workers 
in all jobs against all respiratory hazards. The industrial 
hygienist or other professional responsible for providing 
respiratory protection or evaluating respiratory protection programs 
is therefore encouraged to evaluate as accurately as possible the 
actual protection being provided by the respirator (NIOSH, May 
1987).

    Furthermore, in its Guide to Industrial Respiratory Protection 
(September 1987), published after the NIOSH Respirator Decision Logic, 
NIOSH offered an additional caution with regard to the effectiveness of 
PAPRs:

    Until recently, powered air-purifying respirators were 
considered positive pressure devices. Field studies by NIOSH as well 
as others, have indicated that these devices are not positive 
pressure, and that their assigned protection factors are 
inappropriately high. (NIOSH, September 1987).

    There is virtually no positive pressure in the PAPR. Respirable 
dust may enter the miners' breathing zone through openings along the 
side and bottom of the visor, even when it is in the full lowered 
position. The extent to which respirable dust enters a miner's 
breathing zone, depends, in part, on the velocity of air provided to 
the MMU and on the miner's work rate and his or her angle of 
orientation to the airflow.
    NIOSH recommended in their 1987 Respirator Decision Logic an APF of 
25 for all loose-fitting hood or helmet PAPRs. However, the 
environmental conditions assumed in NIOSH's estimation of an APF for 
PAPRs are not consistent with those in underground longwall mining 
operations, where high air velocities for methane and dust control are 
common. Other, unique conditions of coal mining (obstructed views and 
difficulty communicating) will compel miners to lift their visors. Once 
the visor is raised, the respirator is no longer being worn in 
accordance with conditions required for an APF of 25.
    The actual fit or seal of the respirator helmet to the wearer, 
repeated work-task motions in confined work spaces, raising the visor, 
and high air velocities along the longwall face all may significantly 
reduce the actual degree of respiratory protection provided in the 
workplace. Therefore, it is imperative that such factors be taken into 
account when estimating the degree of workplace respiratory protection 
a PAPR provides to the wearer.
    According to Spear (2000) a workplace protection factor (WPF) is:

[a] measure of the actual protection provided in the workplace under 
conditions of that workplace by a properly functioning respirator 
when correctly worn and used * * * samples [are] taken * * * while 
the respirator is being properly worn and used during normal work 
activities. In practice, the WPF is determined by measuring the 
concentration inside and outside the donned [worn] respirator during 
the activities of a normal workday.

    An effective protection factor (EPF) is another form of estimate of 
efficacy of a respirator given its typical use. According to Spear 
(2000) an EPF is:

[a] measure of the actual protection provided in the workplace under 
the conditions of that workplace by a properly functioning 
respirator, defined as the ratio of concentration outside to 
concentration inside * * * samples [are] taken * * * during normal 
work activities, while the respirator is being worn and not worn. 
Because concentration outside and concentration inside are measured 
during periods of use as well as during periods of non-use, EPFs are 
considered as estimates of the effectiveness of respirator use 
policies, rather than of intrinsic respirator performance 
capability.

    A fourth type of protection factor, a program protection factor 
(PPF) was presented by 3M. In addition to the variables accounted for 
in an EPF, a PPF reflects factors affecting the respirator programs 
effectiveness including:

* * * respirator selection, the respirator design, training, 
maintenance, storage, supervision, program administration and 
monitoring, and any other variable that affects program 
effectiveness. If any of these program elements are deficient, the 
program protection factor will be adversely affected.

    An EPF is predicated upon proper fit and maintenance of a 
respirator, where a PPF is not. Unlike an APF or a WPF, an EPF reflects 
the degree of respiratory protection provided by a respirator over an 
actual work shift given specific occupational environmental conditions, 
such as the velocity of air provided to control methane and respirable 
dust, and the time when miners must raise their visors to speak or see, 
given that a miner performs typical work activities and uses the 
respirator in a typical manner. Based on MSHA experience and miners' 
testimony, it is not reasonable to expect underground coal miners to 
always wear the visor down. Due to this eventuality and MSHA's 
requirement for an approved respiratory protection program, an EPF 
study or studies, which reflect the conditions on longwall MMUs, such 
as high air velocities (i.e., exceeding 800 feet per minute (fpm)), 
would provide suitable data for determining the effectiveness of PAPRs 
used there.
    Although not specifically discussed in the 2000 proposed rule, MSHA 
had reviewed each of the more than one dozen protection factor studies 
submitted in Energy West's 1997 petition for rulemaking. The Agency 
also reviewed the additional relevant studies submitted by commenters 
in response to the previous proposed rule, as well as studies MSHA 
identified. A review of the literature identified the fundamental fact 
that effectiveness of

[[Page 10803]]

PAPRs in longwall mines is mediated by the high velocities of air 
customarily found there. Those velocities are not comparable to the air 
velocities experienced in most industry sectors nor in those 
represented in the studies used to determine the APF of 25, nor in the 
majority of studies submitted by Energy West in 1997.
    The headgate and tailgate air velocities observed by MSHA at 55 
longwall MMUs were reviewed in 1999. These velocities ranged from 365 
to 1,645 fpm and from 200 to 1,400 fpm, respectively. More importantly, 
headgate velocities at 60 percent of the MMUs exceeded 500 FPM and some 
18 percent exceeded 800 fpm. Approximately 55 percent of tailgate 
velocities exceeded 500 fpm and 11 percent exceeded 800 fpm.
    Laboratory and in-mine studies (EPF studies) show that air velocity 
is the single biggest factor affecting the degree of respiratory 
protection provided by a PAPR. While important at longwall MMUs, air 
velocity does not significantly affect PAPR performance at non-longwall 
MMUs where the velocity of air provided to control methane and 
respirable dust is normally less than 100 fpm. There, the primary 
concern is the PAPR's ability to protect the miner from exposure to 
excessive quartz levels. Cecala, et al., (1981) found protection of 
Racal[reg] Airstream helmets to be inversely related to 
ambient air velocity in both laboratory and in-mine settings (Ibid). In 
other words, increased air velocity leads to decreased effectiveness of 
the PAPR.
    The expected degree of workplace respiratory protection that would 
be provided by a properly functioning PAPR is also affected by the 
orientation of the helmet to the airflow. Cecala's wind tunnel tests 
clearly showed that, at the higher airflow rates, helmet efficiency was 
greatest when facing directly against the airflow and was reduced when 
the helmet was oriented in other directions. This is extremely 
important since miners are more likely to orient their heads at an 
angle to the airflow, or to face downwind, than to face directly into 
the airflow.
    Cecala's in-mine testing of the PAPRs produced an EPF confirming 
the inverse relationship between air velocity and the level of 
protection provided by PAPRs shown during wind tunnel testing. Under 
air-velocity conditions less than 400 fpm, the Airstream helmet 
averaged a respirable dust reduction of 84 percent, which is equivalent 
to an EPF of 6.4. However, under higher air-velocity conditions (1,200 
fpm), the helmet's dust reduction performance decreased significantly, 
averaging only 49 percent, which is equivalent to an EPF of 2. The 
higher face air-velocity conditions in this study best represent the 
higher velocities observed on longwalls. Today, the face air velocity 
in over 60 percent of the longwall MMUs exceed 500 fpm (MSHA, October 
1999). Thus, it is critical to take into account the air velocity 
conditions when determining a PF for PAPRs used in underground coal 
mines.
    Other researchers have reported that helmeted PAPR systems are 
vulnerable to inward leakage into the wearer's breathing zone (Howie, 
et al., 1987; Sherwood, 1991). For example, Howie, et al., found that 
increasing airflow velocities from approximately 400 to 800 fpm doubled 
the inward leakage of the helmet when the airflow impinged on the 
wearer's head only, and increased the leakage further when the airflow 
impinged on the wearer's body and head (Howie, 1987). Subsequent 
testing of a redesigned unit at a wind velocity of approximately 700 
fpm showed decreased inward leakage, yielding a PF of 6.3. This met the 
target PF of 5, which was subsequently proposed by the European 
Community to be the standard for powered helmet respirators.
    More recent studies conducted by Bhaskar, et al. (1994) at four 
western longwall MMUs indicated that, under these workplace conditions, 
PAPRs had an average dust reduction efficiency of 83.8 percent (Ibid.). 
Although a different sampling procedure was employed, this result is 
consistent with the performance (average value of 84 percent) obtained 
by Cecala, et al., under air-velocity conditions less than 400 fpm. 
During the test period, Bhaskar reported headgate face velocities 
ranging from 345 to 500 fpm, with approximately 88 percent of the 
recorded velocities falling below 500 fpm. The tailgate face velocities 
ranged from 280 to 550 fpm and only one exceeded 500 fpm. None of these 
tests were conducted under face-velocity conditions that exceeded 800 
fpm. As such, this study provides information on their effectiveness at 
lower velocity applications (i.e., under 500 fpm).
    In summary, there is consensus among studies that the effectiveness 
of the PAPR is reduced when air velocities are increased. The Cecala 
(1981) study alone, provided reasonable estimates of the degree of 
respiratory protection that PAPRs would provide to a wearer working on 
a longwall MMU where the face velocity exceeds 800 fpm. Consequently, 
this study provides the best data from which to estimate PAPR 
performance or the PF that should be assigned to PAPRs authorized for a 
particular MMU. As discussed elsewhere in this proposed rule, MSHA is 
proposing to allow the use of PAPRs only as a supplementary control 
measure after all feasible engineering controls have been applied to 
reduce exposure to the lowest possible level. In our view, these 
measures, when properly applied and maintained, will control respirable 
dust to a level reasonably near the applicable dust standard. 
Therefore, it would not be in the miner's best interest or necessary 
for compliance purposes to apply the highest PF suggested by these 
studies. Accordingly, MSHA is proposing that a PF factor of 4 be 
applied when using a PAPR under air velocity conditions of 400 fpm or 
less and a PF of 2 when the air velocity is equal or exceeds 800 fpm. 
This approach recognizes the increased level of respiratory protection 
that PAPRs afford at lower air velocities and, based on our engineering 
judgement, will allow operators to achieve compliance with the 
applicable dust standard on longwalls and other MMUs. Furthermore, the 
level of protection provided by a properly used PAPR will assure miners 
that they are being protected from overexposure.
    For example, if the air velocity to be maintained in the headgate 
and tailgate of a longwall MMU ventilated head to tail is 400 fpm and 
300 fpm, respectively, then PAPRs used there would be assigned a PF of 
4. If on the other hand, the ventilation plan calls for 850 fpm to be 
maintained in the headgate location and 450 fpm in the tailgate 
location, then the applicable PF would equal 2. Because of the lack of 
data on PAPR performance under air-velocity conditions ranging between 
400 fpm and 800 fpm, MSHA has proposed that, whenever plan velocities 
fall in that range, PAPRs used in the MMU be assigned a corresponding 
PF falling between 2 and 4 which would be determined using an 
interpolation formula [2 x (800/air velocity)]. For example, if the air 
velocity to be maintained in the headgate location is 700 fpm, then the 
applicable PF would equal 2.3 [2 x 800fpm/700fpm].
    The following example is meant to illustrate the application of the 
PF to determine the dust concentration to which the wearer of a PAPR is 
expected to be exposed. Assume for purposes of the example that the 
applicable dust standard is 1.5 mg/m3 and the airborne 
concentration of respirable dust is 2.6 mg/m3. Therefore, 
using a PAPR with a PF =4 is expected to reduce the miner's exposure to 
0.65 mg/m3 (2.6 mg/m3 4).
    The range of PFs that MSHA will allow to be assigned to PAPRs under 
this proposed rule will provide a margin

[[Page 10804]]

of safety for the miner. However, regardless of the particular PF 
allowed by MSHA, full compliance with the provisions of the approved 
respiratory protection program is necessary to ensure that a PAPR's 
protective value is not compromised.

E. Guidelines for Determining What Is a Feasible Dust Control

    This proposed rule requires a mine operator to implement all 
feasible engineering or environmental controls that are technologically 
and economically feasible to control respirable coal mine dust. The 
Federal Mine Safety and Health Review Commission (Commission) has 
addressed the issue of what MSHA must consider when determining what is 
a feasible control for enforcement purposes. In cases involving the 
noise standard for metal and nonmetal mines, the Commission has held 
that a control is feasible when it: (1) Reduces exposure, (2) is 
economically achievable, and (3) is technologically achievable. See 
Secretary of Labor v. Callanan Industries, Inc., 5 FMSHRC 1900 (1983), 
and Secretary of Labor v. A.H. Smith, 6 FMSHRC 199 (1984).
    In determining technological feasibility of an engineering control, 
the Commission has ruled that a control is deemed achievable if through 
reasonable application of existing products, devices, or work methods 
with human skills and abilities, a workable engineering control can be 
applied to the exposure source. The control does not have to be ``off-
the-shelf'' or already available but, it must have a realistic basis in 
present technical capabilities. Further, the Commission has held that 
MSHA must assess whether the cost of the control is disproportionate to 
the ``expected benefits,'' and whether the cost is so great that it is 
irrational to require its use to achieve those results. The Commission 
has expressly stated that a cost-benefit analysis is unnecessary in 
order to determine whether an engineering control is feasible. 
According to the Commission, an engineering control may be feasible 
even though it fails to reduce the exposure to permissible levels in 
the standard, as long as there is a significant reduction in exposure.
    Consistent with the Commission case law, MSHA would consider three 
factors in determining whether engineering or environmental controls 
are feasible at a particular mine: (1) The nature and extent of the 
overexposure; (2) the demonstrated effectiveness of available 
technology; and (3) whether the committed resources are 
disproportionate to the expected results. As explained in the 
discussion of Sec.  70.209 in Section IV of this proposed rule, the 
formal determination of whether all feasible engineering or 
environmental controls have, in fact, been implemented at a specific 
mine to prevent excessive dust concentrations will be made by the 
Administrator for Coal Mine Safety and Health based on the best 
available information, experience, and engineering judgement.

F. Application of New Technology for Monitoring Coal Mine Dust Levels

    Because of the ever changing mining environment, more timely 
feedback on current dust conditions in the workplace should enhance 
miner health protection from coal workers' pneumoconiosis (CWP) and 
silicosis. To obtain such feedback requires a type of dust monitoring 
instrument designed to directly measure on a continuous basis the 
amount of respirable coal mine dust that is present in the work 
environment. The availability of this information on a real-time basis 
would enable mine personnel to optimize mining procedures and dust 
control parameters when dust levels approach the applicable dust 
standard, thus averting possible overexposure. Knowing the actual dust 
levels during the shift would also empower the miner to be more 
directly involved in the dust control process to safeguard their 
health.
    The current monitoring program, which has been in effect since 
1970, lacks this capability. Samples results are not known by mine 
personnel until days after completion of sampling. If there is an 
overexposure, corrective action does not occur until the overexposure 
has been confirmed by the dust processing laboratory and communicated 
to the operator and MSHA. Consequently, any corrective action that may 
be taken would only impact exposures on subsequent shifts. Therefore, 
the ability to continuously monitor and display dust concentrations 
during the shift, rather than depend solely on periodic measurements 
under the existing program, has been a goal for nearly two decades. 
Recent advancements in personal dust monitoring technology make this 
goal achievable within the next two years, presenting opportunities to 
further improve miner health protection from disabling occupational 
lung disease.
    The health benefits of continuous monitoring were recognized by 
both the Task Group and the Dust Advisory Committee. In 1992, the Task 
Group concluded that continuous monitoring of the mine environment and 
dust control parameters offered the best long-term solution for 
preventing occupational lung disease among coal miners. Similarly, the 
Dust Advisory Committee found that:

    Worker exposure to excessive levels of dust can be prevented by 
implementing a hazard surveillance program that provides mine 
personnel with current information on actual dust levels in the work 
environment at all times, and on the status of key dust control 
parameters.

    The Dust Advisory Committee's final report issued in 1996 made the 
following recommendation with regard to continuous dust monitors:

    Once the technology for continuous dust monitors has been 
verified, these measures should be broadly applied in conjunction 
with other sampling methods for surveillance and determination of 
dust control at all MMUs and other locations at high risk of 
elevated dust exposure.

    Over the past decade significant progress has been made as a result 
of the R&D efforts sponsored by the former U.S. Bureau of Mines in 
conjunction with MSHA. These efforts have advanced the technology for 
directly measuring and displaying the amount of respirable coal mine 
dust contained in mine air in real time, based on an inertial 
microweighing method called tapered element oscillating microbalance 
(TEOM[reg]). The development and commercialization of this technology 
was pioneered by Rupprecht & Patashnick Co., Inc. (R&P).
    A TEOM-based monitor consists of a filter mounted on the end of a 
hollow tapered tube. The other end of the tube is fixed rigidly to a 
base. The tube with the filter on the free end is oscillated at its 
natural frequency. This frequency depends on the physical 
characteristics of the hollow tube and the mass on its free end. Mine 
air is drawn through the filter that removes the respirable coal mine 
dust and then through the hollow tube. As more respirable dust 
particles are removed and deposited on the filter, the mass of the 
filter increases which causes the frequency of the tapered element to 
decrease. Because of the direct relationship between mass and frequency 
change, the amount of respirable coal mine dust deposited on the filter 
is determined by accurately measuring the frequency change. By 
combining the mass of dust and the known volume of air that was drawn 
through the filter during the period sampled yields a measurement of 
the respirable dust concentration.
    While the capabilities of the TEOM method have been applied to a 
variety of particle monitoring applications, the first instrument 
designed specifically for mine use based on this technology was

[[Page 10805]]

a machine-mounted continuous respirable dust monitor (MMCRDM). In-mine 
testing of the prototype MMCRDM in the late 1990s demonstrated the 
capability of the TEOM system to produce dust measurements in a mining 
environment. However, because instrument accuracy could not be 
determined by in-mine testing and questions about the comparability of 
fixed-site versus personal sampling, NIOSH decided to discontinue final 
development of the MMCRDM.
    In 1999, at the urging of labor and industry, NIOSH, in conjunction 
with MSHA, funded the development of a personal dust monitor (PDM) 
based on the TEOM technology used in the MMCRDM. The ability to 
miniaturize the TEOM dust sensor without compromising its performance 
made it possible in 2000 to develop the first PDM capable of directly 
measuring in real-time and displaying the concentration of respirable 
coal mine dust. The PDM-2, as it was called, was a two-piece unit 
consisting of a belt-mounted dust monitor battery/pump pack with a 
display and the TEOM dust sensor that was attached to the lapel like 
the standard sampling device in use today. Although laboratory and in-
mine tests showed the PDM-2 to be dependable and capable of accurately 
measuring the amount of dust that accumulated on the filter, concern 
was expressed by miners about the size of the instrument. Specifically, 
miners believed that since they were already required to carry a cap-
lamp battery and a self-contained self rescuer on their belt, there was 
no room for a separate dust monitor battery/pump pack. They also 
indicated that the TEOM dust sensor was too bulky, heavy and interfered 
with work activity. As a result of these concerns, further efforts to 
refine the PDM-2 were suspended by NIOSH.
    In 2001, NIOSH contracted the development of a one-piece version of 
the PDM that would be less cumbersome to mine workers. Efforts to date 
have produced a belt-worn instrument (PDM-1) that contains the dust 
monitor and the miner's cap lamp battery in a single package. To 
improve wearer convenience and to simplify the monitor, the sample 
inlet for the instrument was moved from the traditional lapel location 
to the cap lamp of the hard hat. A pump mounted in the instrument 
transports the dust-laden air that enters the inlet to the instrument 
through a conductive silicone rubber tube that runs parallel to the 
lamp cord. Unlike the PDM-2 which employed a 10-mm Dorr-Oliver nylon 
cyclone used in the approved sampling device, the PDM-1 uses a Higgins-
Dewell cyclone to separate the non-respirable dust. The redesigned cap-
lamp battery pack contains all the components, including two separate 
batteries, to enable the instrument and cap lamp to be operated 
independently. To accommodate monitoring over an extended shift, the 
PDM-1 was designed to operate continuously for 12 hours.
    The PDM-1 is designed to continuously measure dust levels on real-
time basis and provide information on (1) the cumulative average dust 
exposure during the shift; (2) the current exposure level based on 
entire shift duration (projected end-of-shift exposure); and (3) the 
time-weighted average concentration (total mass of dust collect divided 
by the length of time the unit was operated) within 15 minutes after 
the end-of-shift. The unit is capable of being used either in a shift 
mode in which the instrument is programmed to operate for a specific 
shift length (e.g., 8, 10, 12 hours) or in an engineering mode. When 
operated in the engineering mode, the miner could program periods 
during the shift to record dust levels during specific mining cycles or 
at specific dust-generation sources in the mine. The display on the 
instrument has various screens that show the (1) current time of day, 
(2) elapsed time since beginning of the shift, (3) total amount of dust 
accumulated on the filter since the start of sampling which is stored 
in an internal memory for analysis, (4) dust concentrations, and (5) a 
bar graph that shows the average dust concentration of the last 30 
minutes. The PDM-1 is also capable of showing whether the instrument 
was bumped significantly or tipped beyond 90 degrees. This information 
will be stored along with information on the amount of dust that has 
accumulated on the filter and the concentration data which can be 
accessed with a personal computer at the end of the shift and analyzed. 
While the performance of the PDM-1 to accurately and precisely measure 
respirable coal mine dust in the mine environment and its durability 
under in-mine conditions has yet to be extensively evaluated, 
preliminary indications from the limited testing performed to date are 
that the PDM-1 has the potential to provide timely information on dust 
levels and miner exposure. Although MSHA has confidence in this 
technology, a final determination of the applicability and suitability 
of PDMs under the conditions of use being proposed is not expected 
until after completion of the scheduled laboratory and in-mine testing 
and evaluation at the end of 2003. Both NIOSH and MSHA recognize that 
to be accepted by the mining community, the PDM must reliably monitor 
respirable dust concentrations in the mine environment with sufficient 
accuracy to permit exposures to be effectively controlled on each 
shift.
    Accordingly, as recommended by the Dust Advisory Committee and 
urged by the mining community, MSHA is encouraging deployment of 
personal continuous dust monitoring technology once verified as 
reliable under in-mine conditions by proposing a new standard for the 
use of such monitors as part of a comprehensive dust control program. 
As discussed under proposed Sec.  70.220, operators would be permitted 
to use PDMs capable of continuously measuring and displaying dust 
levels during the shift in conjunction with engineering and 
administrative controls. Each miner would be required to wear such a 
device on each shift, unless the operator successfully demonstrated 
during verification sampling that the exposure of each miner working on 
the same shift is represented by sampling the DO and/or another 
occupation under administrative control. For additional specific 
details regarding the proposed application of PDM under this proposed 
rule refer to the discussion of Sec.  70.220 in section IV of the 
preamble.

IV. Section-by-Section Discussion of Proposed Rule

A. Part 70

    The following explains, section-by-section, each provision of the 
proposed rule. The text of the proposed rule is included at the end of 
the document.
Section 70.1 Scope
    Under the proposed rule, the existing scope will remain the same. 
It sets forth mandatory health standards for each underground coal mine 
subject to the Federal Mine Safety and Health Act of 1977.
Section 70.2 Definitions
    The technical terms that were developed for use in this part are 
defined in the proposed rule. These include ``citation threshold 
value,'' ``dust control parameters,'' and ``engineering or 
environmental controls.'' Some existing definitions of terms such as 
``certified person'' and ``respirable dust'' have been modified to more 
clearly convey the intended meaning under the proposed rule. These and 
other modifications discussed below reflect changes resulting from the 
removal of existing paragraphs, the transfer of other paragraphs, and 
the

[[Page 10806]]

addition of new regulatory text. Other changes were made in response to 
previous commenters to make them consistent with the common usage of 
such terms. For example, under this new proposed rule, the Agency's 
definition of the term ``concentration'' has been changed to reflect 
the conventional definition. In doing so, it was necessary to include 
and define a new term ``equivalent concentration,'' which originally 
appeared within the proposed definition of the term ``concentration'' 
in the previous proposed rule.
    This proposed rule also defines new terms to clarify the process of 
verifying the adequacy of the dust control parameters specified in a 
mine ventilation plan in controlling respirable dust in a mechanized 
mining unit. Specifically, MSHA provides definitions of ``critical 
value,'' ``protection factor,'' ``verification limits,'' and 
``verification production level.'' Finally, the definition of ``normal 
production shift'' would be removed to be consistent with the proposed 
revocation of operator sampling requirements for purposes of 
determining compliance with the applicable dust standard.
    The proposed rule also includes other terms like ``feasible'' for 
example, which have not been defined. The term as used applies to the 
suitability of the types of engineering or environmental controls 
required to control respirable dust under prescribed operating 
conditions. Since individual mine conditions would dictate the type of 
engineering or environmental controls to be considered as suitable 
candidates, MSHA has refrained from providing an explicit definition of 
this term. Instead, as noted in the discussion under section III.E. of 
this preamble, MSHA intends to follow the Federal Mine Safety and 
Health Review Commission case law as to what constitutes a feasible 
control for enforcement purposes. The Agency further notes in that 
discussion that the final determination of whether a particular 
operator has implemented all feasible engineering or environmental 
controls would be made by the Administrator for Coal Mine Safety and 
Health. That determination would be based on the best available 
information and on the combined experience and engineering judgement of 
an MSHA expert panel.
    The following explains the new and revised definitions of terms 
that are used in the proposed rule. Please closely examine the context 
of the term as used in each proposed section.
Administrative Control
    ``Administrative control'' would mean a work practice intended to 
reduce an individual miner's exposure to respirable dust at the 
assigned job position or occupation by altering the way in which the 
assigned work is performed. Examples include rotation of miners to 
areas having lower concentrations of respirable dust, altering the way 
in which specific tasks are performed, rescheduling of tasks, and 
modifying work practices to reduce exposure. An ``administrative 
control'' must be (1) capable of being objectively reviewed and 
monitored to confirm that it has been properly implemented, (2) clearly 
understood by the affected miners for the controls to be effective, and 
(3) applied consistently over time.
Approved Sampling Device
    ``Approved sampling device'' would mean a sampling device approved 
by the Secretary and the Secretary of Health and Human Services under 
part 74 (Coal Mine Dust Personal Sampler Units) of this title; or 
approved by the Secretary when it has been demonstrated that a 
respirable dust concentration measurement can be converted to a 
concentration measurement equivalent to that obtained with an approved 
sampling device. Under the proposed rule, MSHA will continue to use 
sampling devices approved by NIOSH pursuant to existing 30 CFR part 74. 
To accommodate the adoption of advanced sampling devices in the future 
such as continuous respirable dust monitors, the proposed rule would 
permit the Secretary to approve and use any technologically advanced 
sampling device that should become available in the future but could 
not be approved under the regulatory requirements of 30 CFR part 74.
    Therefore, under the proposed rule, any newly developed sampling 
instrument would be considered an approved device pursuant to this 
definition when the Secretary demonstrates that the respirable dust 
concentration measured by the new instrument can be converted to a 
concentration measurement equivalent to that obtained by a device 
approved under 30 CFR part 74 of this title.
    To encourage greater innovation in sampler design without 
compromising accuracy, comments are specifically solicited on this 
approach of approving sampling devices. MSHA also solicits comments on 
an alternative approach based on the International Standards 
Organization (ISO) definition of respirable dust.
Certified Person
    The existing definition would be modified by removing references to 
existing Sec. Sec.  70.202 and 70.203. The provision requiring the use 
of a certified person to conduct sampling is being transferred to 
revised Sec.  70.201. Existing Sec.  70.203 which requires approved 
sampling devices to be maintained and calibrated by a certified person 
will be retained and redesignated as Sec.  70.202.
Citation Threshold Value (CTV)
    ``Citation threshold value'' would mean the lowest acceptable 
equivalent dust concentration measurement demonstrating that the 
applicable dust standard has been exceeded at a high level of 
confidence and at which MSHA would cite an operator for a violation of 
Sec. Sec.  70.100 or 70.101 under proposed Sec.  70.218. Since MSHA 
would be assuming responsibility for all compliance sampling under this 
proposed rule, a determination of noncompliance would be based solely 
on the results of single-shift samples collected by MSHA. Appendix C 
explains how each critical value listed in Table 70-1 was derived. Each 
CTV is calculated to ensure that a citation will be issued only when a 
single-shift sample demonstrates noncompliance with at least 95 percent 
confidence.
Concentration
    The existing definition would be modified by replacing the term 
``substance'' with ``respirable dust'' to more clearly convey the 
meaning under the proposed rule.
Control Filter
    ``Control filter'' would mean an unexposed or clean filter cassette 
of the same design and material as the exposed filter cassette used for 
sampling that is pre- and post-weighed on the same day as the exposed 
filters. Its use is intended to eliminate the potential for any bias 
that may be associated with day-to-day changes in laboratory conditions 
or introduced during storage and handling of the filter capsules. The 
control filter is used to adjust the resulting weight gain obtained on 
each exposed filter capsule. That is, any change in the weight of the 
control filter will be subtracted from the change in weight of each 
exposed filter.
Critical Value
    ``Critical value'' would mean the maximum acceptable equivalent 
dust concentration measurement demonstrating that the applicable 
verification limit has been met at a high level of confidence. Appendix 
A

[[Page 10807]]

explains how each critical value listed in Table 70-1 was derived.
Designated Area (DA)
    The existing definitions would be modified to certify that the 
Secretary may identify DAs which is consistent with existing procedures 
that have been in effect since 1980. Once identified, the location of 
these DAs and the respirable dust control measures to be used at the 
dust generating sources for these locations must be contained in the 
operator's approved mine ventilation plan as provided for under Sec.  
75.371(t) of this title. However, the operator would not be required to 
sample these areas under the proposed rule. MSHA is also proposing to 
transfer the requirement for identifying each DA as specified in 
existing Sec.  70.208(e) to revised Sec.  70.2.
Dust Control Parameters
    ``Dust control parameters'' would mean the respirable dust control 
provisions specified in an approved mine ventilation plan, including 
specific engineering or environmental controls, maintenance procedures, 
and other measures designed to control respirable dust levels in the 
working environment. These may also include, if approved by MSHA, 
supplementary controls such as powered air-purifying respirators and 
administrative controls. These measures are required for the protection 
of miners from excessive levels of respirable dust and must be in use 
on every production shift.
Engineering or Environmental Controls
    ``Engineering or environmental controls'' would mean methods that 
are designed to control the quantity of respirable dust that is 
released into the work environment by affecting the rate of generation 
or by suppressing it at the source of generation, or by diluting, 
capturing or diverting the generated dust. Examples include improved 
cutting tools, deep-cutting, water-spray delivery systems and 
orientation, air quantities and velocities, dust collectors, and 
passive barriers. Throughout the proposed rule, the terms 
``engineering'' and ``environmental'' controls are used 
interchangeably.
Equivalent Concentration
    ``Equivalent concentration'' would mean the concentration of 
respirable dust, as measured by an approved sampling device, converted 
to an 8-hour equivalent concentration as measured by a Mining Research 
Establishment (MRE) sampler. This conversion is normally accomplished 
in two steps, unless powered air-purifying respirators (PAPRs) are 
used, and then an additional adjustment is made to account for the 
expected workplace level of respiratory protection being provided the 
wearer. In the first steps, the concentration measurement is multiplied 
by a constant factor prescribed by the Secretary specifically for the 
approved sampling device. In the second step, that result is then 
multiplied by t/480, where t is the sampling time in minutes if longer 
than eight hours, to make it equivalent in dosage to the concentration 
as measured by an MRE sampler on an 8-hour work shift. Since 
verification sampling will be conducted over the course of a full 
production shift of the MMU only, and not over the miner's entire work 
shift which includes travel to and from the MMU, except when employing 
personal continuous dust monitors (PCDM), t will also be equal to the 
length of a full production shift. If the full production shift is 
eight hours or less, then t must equal 480 minutes.
    In cases where PAPRs are used, the equivalent concentration 
measurement obtained following step two is adjusted further to account 
for the expected workplace level of respiratory protection being 
provided the wearer. This is accomplished by dividing the equivalent 
concentration by the protection factor specified in the approved 
ventilation plan for the mechanized mining unit under a PAPR protection 
program. The result represents a surrogate measure of the respirable 
dust concentration to which the miner is exposed while wearing the 
PAPR.
    The current U.S. coal mine applicable dust standard is based on 
epidemiologic studies of British coal miners. In these studies, miners 
routinely worked 8-hour shifts and their respirable dust exposures were 
assessed based on 8-hour measurements using an instrument known as the 
MRE instrument. Work shifts in U.S. coal mines now frequently exceed 
eight hours. Therefore, to provide the intended level of protection to 
miners working longer than eight hours, it is necessary to convert dust 
concentration measurements to equivalent, 8-hour values as measured by 
the MRE instrument.
    The first step in the conversion from ``concentration'' to 
``equivalent concentration'' is intended to make the measurement 
equivalent to the concentration measured by an MRE instrument. This 
instrument was designed to selectively collect airborne dust in a way 
that would approximate the deposition of inhaled particles in the lung. 
Because the MRE instrument was large and cumbersome, other more 
portable samplers were developed for use in U.S. coal mines. Currently 
approved sampling devices use a 10-mm nylon cyclone to separate the 
respirable fraction of airborne dust, instead of the four horizontal 
plates used in the MRE instrument. Such differences in instrument 
design lead to systematic differences in the amount of dust collected. 
Since 1980, measurements made using the currently approved cyclone-
based devices operating at a flow rate of 2.0 liters per minute (lpm) 
were multiplied by the constant factor of 1.38 prescribed by the 
Secretary for the approved sampling device used. Application of this 
factor compensates for the difference in dust collection 
characteristics and makes the measurements equivalent to what would be 
obtained using an MRE instrument.
    Similarly, the second step in the conversion from ``concentration'' 
to ``equivalent concentration'' is intended to compensate for 
differences between current conditions and conditions under which the 
existing applicable dust standards were developed. Specifically, it is 
designed to ensure that miners working shifts longer than eight hours 
will be afforded the same level of protection as miners working an 8-
hour shift. MSHA developed the existing standards from 8-hour shift 
exposure measurements. Therefore, MSHA will adjust the measured 
concentration to be equivalent, in its effect on cumulative exposure, 
to a concentration over an 8-hour exposure period. This is accomplished 
by multiplying the concentration measurement by t/480, where t is the 
sampling time (i.e., length of the sampled shift) in minutes.
    The formula for an equivalent concentration is:
    [GRAPHIC] [TIFF OMITTED] TP06MR03.002
    

[[Page 10808]]


where t = sampling time in minutes and airflow rate = 0.002 
m3/min). The product of t and the airflow rate is the total 
volume of air from which dust is accumulated on the filter.
    The following example is meant to illustrate the effect of the 
second step in the conversion, multiplication by t/480, which adjusts 
for the full length of the sampled shift. Suppose a DO sample is 
collected over a 9-hour shift and that the amount of dust accumulated 
during the shift is 1.5 mg. If the concentration were not adjusted to 
an 8-hour equivalent concentration, the MRE-equivalent concentration 
would be calculated as 1.92 mg/m\3\. Under the proposed definition of 
``equivalent concentration,'' this quantity is then multiplied by 540/
480, yielding an equivalent concentration measurement of 2.16 mg/m\3\. 
Let us suppose now that this concentration measurement was for a 
longwall occupation under a PAPR protection program with an applicable 
protection factor of 2. Therefore, the concentration measurement of 
2.16 mg/m\3\ is divided by 2, which yields 1.08 mg/m\3\, the equivalent 
concentration to which the wearer of the PAPR is exposed.
    This adjustment does not change the daily limit on the accumulated 
dose of respirable coal mine dust as intended by the existing exposure 
limit for coal mine dust. Since the current limit was based on the 
assumption that exposure occurs over an 8-hour shift, it corresponds to 
a daily cumulative dose of respirable coal mine dust of 8 x 2.0 = 16 
mg-hr/m\3\ as measured by the MRE instrument. The proposed definition 
of equivalent concentration will maintain this same MRE-equivalent 16 
mg-hr/m\3\ daily limit, regardless of the length of the working shift 
being sampled.
    To continue the example, the exposure accumulated during the 
sampled working shift is the same, whether over 8 hours at an average 
of 2.16 mg/m\3\ or over 9 hours at an average of 1.92 mg/m\3\. In 
either case, the MRE-equivalent exposure accumulated during the sampled 
shift is 17.3 mg-hr/m\3\, which exceeds the intended limit of 16 mg-hr/
m\3\. Under the definition of ``equivalent concentration'' provided 
here, this will be reflected by the fact that, when more than 16 mg-hr/
m\3\ (MRE-equivalent exposure) is accumulated over the course of the 
particular shift sampled, the equivalent concentration will exceed 2.0 
mg/m\3\, regardless of the shift's length.
    Similarly, using a currently approved sampler, the plan 
verification limit for respirable quartz dust (i.e., 0.1 mg/m\3\) will 
be exceeded when the total amount of quartz dust amassed on a filter 
during the full production shift exceeds 0.07 mg, regardless of the 
shift's length. For example, if 0.08 mg of quartz dust were accumulated 
over the course of a 12-hour shift, then the equivalent concentration 
of respirable quartz dust would be calculated as:
[GRAPHIC] [TIFF OMITTED] TP06MR03.003

    This is exactly the same value of the equivalent concentration that 
would be obtained if 0.08 mg of quartz dust were accumulated on an 8-
hour shift.
    MSHA originally proposed a different but mathematically equivalent 
method of adjusting concentrations to an 8-hour equivalent and 
solicited comments on the proposed method. The proposed method would 
have defined ``concentration'' to mean what is here defined as 
``equivalent concentration.'' Instead of making an explicit adjustment 
to the concentration, using the factor of t/480 as in the present 
definition, the proposed rule would have substituted 480 for the actual 
sampling time in the definition of respirable dust concentration. The 
proposed definition of ``equivalent concentration'' is meant to both 
preserve the ordinary definition of ``concentration'' and to clarify 
the adjustment to an 8-hour equivalent.
    MSHA believes that the proposed adjustment to an ``8-hour 
equivalent concentration'' is necessary to protect miners, who normally 
work nontraditional or extended shifts, from excessive exposures. A 
miner working for ten hours at an average concentration of 2.0 mg/m\3\ 
will inhale and retain more respirable coal mine dust as a result of 
that specific shift than a miner working for eight hours at the same 
average concentration. By comparing the adjusted concentration to the 
concentration limit originally intended for miners working an 8-hour 
shift, the same cumulative exposure limit is applied on individual 
shifts for all miners.
    It should be noted that the American Conference of Governmental 
Industrial Hygienist (ACGIH) approach of reducing the permissible 
concentration to compensate for the extension of a shift beyond eight 
hours is similar in its effect to the approach taken here of adjusting 
the equivalent concentration upwards and comparing it to a fixed limit. 
MSHA makes similar adjustments for extended work shifts in the 
enforcement of exposure limits in metal and nonmetal mines under 30 CFR 
56.5001 and 57.5001. Taking into account the reduced recovery time that 
results from an extended work shift would have led to a numerically 
greater and more protective adjustment, but this would also have 
introduced additional complexities in the calculation of equivalent 
concentration measurements. The Secretary believes that the method 
proposed strikes a reasonable balance between no adjustment at all, and 
a far more complex adjustment that would attempt to model clearance, 
deposition, and retention mechanisms.
Material Produced
    ``Material produced'' would mean the amount of coal and/or any 
other substance(s) extracted by a mechanized mining unit during a 
production shift. In order to properly assess the effectiveness of the 
ventilation plan requirements for respirable dust control and for 
subsequent monitoring purposes, MSHA proposes to require that the 
operator record and make available records of the amount of material 
produced by each mechanized mining unit each shift under a new 
paragraph (h) of Sec.  75.370.
Mechanized Mining Unit (MMU)
    The existing definition would be modified by deleting the reference 
to Sec.  70.207(e) (Bimonthly sampling; mechanized mining units), and 
replacing it with proposed Sec.  70.206(d); and by transferring the 
requirements for identifying each MMU specified in existing Sec. Sec.  
70.207(f)(1) and (f)(2), to revised Sec.  70.2.
MRE
    ``MRE'' would mean Mining Research Establishment of the National 
Coal Board, London, England.
Personal Continuous Dust Monitor (PCDM)
    ``Personal continuous dust monitor'' would mean a type of approved

[[Page 10809]]

instrument capable of accurately measuring the concentration of 
respirable dust on a continuous basis during an entire shift and 
displaying in real-time the measured dust exposure information. To meet 
the definition of ``approved device,'' the Secretary must demonstrate 
that the respirable dust concentration measured by such an instrument 
can be converted to a concentration measurement equivalent to that 
obtained by a device approved under 30 CFR part 74 of this title. 
Comments are solicited on the practice of tying the performance of new 
sampler designs to the currently approved sampling device.
    The PCDM must be capable of displaying (1) the cumulative average 
dust exposure during the shift; (2) the current exposure level based on 
entire shift duration (projected end-of-shift exposure); and (3) the 
time-weighted average concentration (total mass of dust collect divided 
by the length of time the unit was operated) within 15 minutes after 
the end-of-shift. The entire unit must comply with MSHA intrinsic 
safety regulations and pass tests for electromagnetic interference for 
emissions using ANSI C95.1-1982 and 47 CFR part 15 and for immunity/
susceptibility using IEC 61000-4. Since work shifts longer than 8 hours 
are common in mining, the PCDM must have sufficient battery capacity to 
operate continuously for up to 12 hours. To ensure that air monitoring 
results are sufficiently accurate across the relevant range of exposure 
levels, the PCDM must meet an accuracy criterion of +/-25% of a 
reference value determined using the currently approved sampling device 
(P/N 45243) with 95% confidence.
    The Agency solicits comments on how continuous dust monitors could 
be applied to limit exposure of coal miners to respirable coal mine 
dust. Specifically, comments are solicited on the proposed performance, 
accuracy, and approval requirements for personal continuous dust 
monitoring devices, and whether less stringent requirements should be 
imposed on devices designed for surveillance and not for compliance 
purposes. What would be an acceptable level of accuracy of such a 
device if used for surveillance purposes (i.e., identifying dust-
generating sources and magnitude of dust concentrations), for 
compliance determinations, or for control enhancement purposes (i.e., 
provide a means to take corrective measures in response to instrument 
readings by adjusting specific controls)? Comments are also solicited 
on the performance requirements for continuous dust monitors used 
primarily for surveillance purposes to prevent an individual miner from 
being overexposed on a particular shift and whether such devices need 
to be first approved by MSHA for use in underground mines.
Powered Air-Purifying Respirator (PAPR)
    ``Powered air-purifying respirator'' (PAPR) would mean a type of 
air-purifying respirator that uses a blower to force ambient air 
through air-purifying elements to the inlet covering (a visor), which 
provides a partial seal with the face, to deliver filtered air to the 
miner's breathing area. This category of respirator must be approved by 
the National Institute for Occupational Safety and Health under 42 CFR 
part 84 and by MSHA under 30 CFR part 18; and, offer head and face 
protection in compliance with 30 CFR 75.1720(a) and (d) of this title. 
The reasons for excluding other types of approved respirators are 
discussed in section III.D.4. of the preamble.
Protection Factor
    ``Protection factor'' (PF) would be a measure of the expected 
degree of workplace respiratory protection that would be provided to 
the wearer by a properly functioning PAPR when correctly worn and used. 
The PF expresses PAPR performance as the ratio of the respirable dust 
concentration outside the respirator facepiece to the concentration 
inside the facepiece. It reflects the effectiveness of a respirator 
used in conjunction with a good respirator protection program. For 
example, a PF of 4 means that the respirator is expected to reduce the 
concentration of respirable dust actually breathed to one fourth of the 
concentration outside the respirator.
    Factors such as air velocity at the working face and raising of the 
visor during the shift significantly impact the effectiveness of a 
PAPR. Therefore, such factors should be taken into account when 
estimating the degree of respiratory protection a PAPR provides in the 
workplace. Although NIOSH has recommended that loose-fitting hood or 
helmet PAPRs should be assigned a PF of 25, the environmental 
conditions observed in the studies used in NIOSH's estimation of an 
assigned protection factor (APF) are not consistent with those found in 
underground coal mines, where high air velocities for methane and dust 
control are common.
    Under this proposal, the PF that would be assigned to PAPRs 
authorized for a particular MMU depends on the air velocity that will 
be maintained at the working face. The applicable PF would be included 
in a written PAPR protection program, which must be approved by the 
district manager before it can be implemented. Based on the available 
technical information and sound engineering judgement, MSHA would 
permit a PF ranging from 2 to a maximum of 4 to be assigned to a 
particular MMU, depending on air velocity.
    If, according to the ventilation plan, the minimum air velocity to 
be maintained in the headgate of a longwall MMU ventilated head-to-tail 
is less than 400 feet per minute (fpm), then PAPRs used in the MMU 
would be assigned a PF equal to 4. If the minimum air velocity to be 
maintained in the location specified in the plan exceeds 800 fpm, then 
the assigned PF would be 2. If the minimum air velocity specified in 
the plan falls between 400 fpm and 800 fpm, then PAPRs used in the MMU 
would be assigned a corresponding PF falling between 2 and 4.
    Because there is a lack of data on the performance of PAPRs under 
actual air-velocity conditions ranging between 400 and 800 fpm, MSHA is 
proposing an interpolation formula [2 x (800/air velocity)] for 
determining the PF to be assigned to a MMU when the specified air 
velocity to be maintained falls in that range. For example, if the 
minimum air velocity to be maintained in the headgate is 550 fpm, then 
the assigned PF would be calculated as: 2 x (800fpm/550fpm) = 2.9. A 
reasonable alternative interpolation formula, 6--(air velocity/200), 
would yield somewhat higher protection factors for velocities between 
400 fpm and 800 fpm. However, given the absence of supporting data, 
MSHA selected the proposed interpolation formula because it yields a 
more conservative PF.
    Comments are invited on the proposed method of establishing the 
applicable PF and on the interpolation formula proposed for specified 
air velocities ranging between 400 fpm and 800 fpm. Data are requested 
in support of any recommendations that different protection factors 
should be assigned to MMUs authorized to use PAPRs.
Quartz
    The existing definition would be modified by specifying the 
analytical method that MSHA has been using since 1983 to determine the 
quartz content of respirable dust samples. The reason for this 
modification is to standardize the analytical procedure, thereby 
enabling other certified laboratories to produce quartz determinations 
compared to those made by MSHA. Also, to accommodate the adoption of 
improved

[[Page 10810]]

or other quartz analytical techniques in the future, the definition of 
``quartz'' has been expanded in the proposed rule to provide MSHA the 
flexibility to use alternative analytical techniques once these 
techniques have been demonstrated to provide quartz measurements that 
are equivalent to the currently used analytical method.
Respirable Dust
    The existing definition has been modified by transferring the 
requirement for what constitutes an approved sampling device to the 
proposed new definition of the term ``approved sampling device'' above.
Verification Limits
    ``Verification limits'' would mean the maximum equivalent dust 
concentration for which the dust control parameters, specified in the 
ventilation plan for a particular MMU, have been verified as effective 
in maintaining dust levels during the entire production shift. Under 
the proposed rule, MSHA will require mine operators to address both 
respirable coal mine dust exposure and the potential for exposure to 
quartz when designing the dust control parameters specified in a mine 
ventilation plan by proposing two separate respirable dust limits--2.0 
mg/m3 for respirable coal mine dust and 100 [mu]g/
m3 for respirable quartz dust for verification sampling.
    The Dust Advisory Committee recognized that a significant quartz 
exposure hazard continues to exist in coal mines, especially for 
operations such as roof bolting. Based on recent MSHA data (April 23, 
2002), 298 or (58 percent) of the 517 producing underground coal mines 
are operating on a reduced applicable dust standard due to the presence 
of high quartz levels in the working environment. This data also shows 
that 65 percent of the more than 470 roof bolters and 27 percent of the 
MMUs required to be sampled bimonthly by mine operators must comply 
with a reduced dust standard. The number of reduced standards in effect 
indicates that quartz exposure remains a significant health risk for 
miners.
    Under the current program, miners can be exposed to excessive 
quartz levels during the period of time necessary to establish the 
applicable dust standard that would apply to a particular MMU. For 
example, consider a recent situation where an MSHA dust sample of a 
roof bolter was 0.9 mg/m3, which complied with the 
applicable dust standard of 1.3 mg/m3. However, the results 
of quartz analysis indicated that the actual concentration of quartz 
dust in the mine environment at the time of sampling exceeded 270 
[mu]g/m3, or more than two and a half times the permissible 
level of 100 [mu]g/m3. The only action that MSHA could take 
in this particular situation is to initiate the process of establishing 
a new applicable dust standard, which, on average, can take at least 
one month or longer. During this period, the existing applicable dust 
standard remains in effect.
    Under the proposed rule, MSHA would require operators to 
incorporate dust control parameters in mine ventilation plans that are 
designed to effectively control exposure to both respirable coal mine 
dust and quartz dust. To ensure the adequacy of the operator's dust 
control strategy, MSHA would determine the mass of quartz contained in 
each verification sample and express the concentration of quartz in the 
mine air as an airborne concentration and not as a percentage as has 
been the long-standing practice.
    MSHA believes that by requiring operators to anticipate exposure to 
quartz dust in the initial design of the dust control parameters, 
especially at those operations with a quartz exposure history, and by 
adopting the new procedures for setting a reduced dust standard as 
outlined in section III.B., the level and quality of miner health 
protection in the workplace will be significantly enhanced.
Verification Production Level (VPL)
    ``Verification production level (VPL)'' would mean the tenth 
highest production level recorded in the most recent 30 production 
shifts. It is an estimate of the 67th production percentile within a 
MMU. Under the proposed rule, the VPL is the minimum production level 
at which the operator must demonstrate the adequacy of the plan 
parameters in controlling respirable dust. To enable the operator to 
establish the VPL required under proposed Sec.  75.371(f), the operator 
would be required to begin maintaining records of the amount of 
material produced by each MMU during each shift in accordance with 
proposed Sec.  75.370(h) of this title.
    If records for 30 production shifts are not available to establish 
a VPL, as in the case of a new MMU, the operator would use the minimum 
production actually achieved on any shift used to verify the adequacy 
of the plan parameters as the VPL. For example, assume an operator 
initiates verification sampling at a longwall MMU. If the dust 
concentration measurements obtained on the first shift exceed either 
1.85 mg/m3 for respirable coal mine dust or 93 [mu]g/
m3 for quartz dust but not the verification limits, the 
operator would need to sample at least two more shifts according to 
Table 70-1 to verify the adequacy of the plan parameters, provided that 
no sample exceeds 1.93 mg/m3 for respirable coal mine dust 
or 97 [mu]g/m3 for quartz dust. If the highest production 
level was achieved on the third shift sampled and the dust 
concentration measurements obtained on that shift were low enough 
according to Table 70-1 to verify the plan parameters on a single 
shift, the operator would establish a VPL equal to the production 
achieved on that shift. If, on the other hand, the dust concentration 
measurements obtained on the third shift with the highest production 
level were not low enough to verify the plan parameters on a single 
shift and a determination of the plan's adequacy was based on these 
three shifts, the operator's VPL would be the minimum production 
achieved during verification sampling. In any case, the VPL would 
become part of the operator's ventilation plan.
Working Face
    ``Working face'' would mean any place in a coal mine in which work 
of extracting coal from its natural deposit in the earth is performed 
during the mining cycle.

Sections 70.100 Through 70.101

Respirable Dust Standards

Section 70.100 Respirable Dust Standards When Quartz Is Not Present
    MSHA is proposing no substantive changes in existing Sec.  
70.100(a) and (b), except for removing the reference to Sec.  70.206 
(Approved sampling devices; equivalent concentrations) from existing 
paragraphs (a) and (b) and replacing it with revised Sec.  70.2. The 
requirements contained in revised Sec.  70.2 are similar to the 
previous standard in Sec.  70.206. The proposed rule retains the 
applicable dust standard of 2.0 mg/m3 in existing paragraph 
(a) and the intake air standard for respirable dust of 1.0 mg/
m3 in existing paragraph (b), which have been in effect 
since 1972.
Section 70.101 Respirable Dust Standard When Quartz Is Present
    MSHA is proposing to retain the existing formula (10 divided by the 
concentration of quartz, expressed as a percentage) for reducing the 
applicable dust standard below 2.0 mg/m3 in proportion to 
the percentage of quartz when the quartz content of the respirable dust 
in the mine atmosphere exceeds 5.0 percent. However, the Agency is 
proposing to change the

[[Page 10811]]

procedures for determining the average quartz percentage used to 
calculate the applicable dust standard. Only the results of MSHA 
samples would be used to establish the applicable dust standard. The 
quartz results of the three most recent valid MSHA samples would be 
averaged and the resultant percentage would be used to set the new 
applicable dust standard. However, if an entity is already on a reduced 
standard when these revised procedures become effective, a new 
applicable dust standard will be established by averaging the results 
of the first two MSHA samples taken under the revised procedures with 
the quartz percentage associated with the reduced standard in effect. 
If fewer than two MSHA samples are taken, the existing applicable dust 
standard will continue to remain effect.
    Application of the revised procedures will result in the setting of 
reduced standards that will (1) more accurately represent the quartz 
percentage of the respirable dust in the environment at the time of 
sampling; (2) reflect the dynamics of the mining process and the 
changing geologic conditions of the mine strata; and (3) continue to 
protect miners over multiple shifts.
    Under the proposed rule, MSHA would also begin reporting the quartz 
content to the nearest tenth of a percent, instead of the current 
practice of truncating results to the nearest full percent. This is 
more protective for the miner because it will permit MSHA to also set 
reduced standards at such levels as 1.1 mg/m3, 1.4 mg/
m3, 1.6 mg/m3, 1.8 mg/m3, and 1.9 mg/
m3. Setting these particular standards was not 
mathematically possible using the above formula due to the practice of 
truncating the average quartz percentage.
Section 70.201 Sampling; General and Technical Requirements
    MSHA is proposing to modify the general requirements for operator 
sampling under existing Sec.  70.201. The proposed rule would remove 
existing paragraph (d), revise and redesignate (b) as (c) and existing 
(c) as (g), revise paragraph (a), and add new (b), (d), (e), (f), (h), 
and (i).
    To minimize repetition and to streamline the proposed requirements, 
paragraph (a) would be modified by removing the reference to part 74 
approval (Coal Mine Dust Personal Sampler Units), and replacing it with 
``approved sampling device,'' as defined under revised Sec.  70.2. 
Respirable dust sampling under this proposed rule could also be 
conducted with sampling devices that can give a continuous readout of 
dust concentrations provided that the measured concentration can be 
converted to an equivalent concentration as measured with another 
sampling device approved under part 74 of this title.
    Proposed new paragraph (b) would retain the requirements in 
existing Sec.  70.202(a) and (b) that sampling required under this part 
be conducted by an individual certified by MSHA and the manner by which 
a person would be certified. Therefore, existing Sec.  70.202(a), (b), 
and (c) would be removed.
    While the sampling device would continue to be worn or carried to 
and from the MMU as required by existing Sec.  70.201(b), proposed 
Sec.  70.201(c), the existing requirement that sampling devices be 
operated portal-to-portal and for a period no longer than eight hours 
would be removed. Instead, since the objective is to assess the 
adequacy of the dust control parameters in effect in each MMU under 
proposed Sec.  70.206 and Sec.  70.215, except when using a personal 
continuous dust monitor (PCDM) under proposed Sec.  70.220, the 
sampling device would be operated only during the period that the 
production crew spends in the MMU. That is, under proposed Sec.  70.206 
the sampling device would (1) be turned ``ON'' when the production crew 
arrives at the MMU, regardless if any actual mining is taking place; 
(2) remain operational during the entire shift that the production crew 
remains in the MMU, regardless of the number of hours worked; and (3) 
be turned ``OFF'' at the end of the shift as the production crew exits 
the MMU.
    On the other hand, if using a PCDM under proposed Sec.  70.220, the 
sampling device would be operated portal-to-portal and would remain 
operational during the entire work shift or for 12 hours, whichever 
time is less, to ensure that the miner's entire work shift is 
controlled. Because the use of a PCDM will permit the operator to make 
adjustments in administrative controls, without MSHA approval, at 
anytime during the work shift, the duration of sampling is not limited 
to the time period the production crew spends in the MMU as discussed 
in the previous paragraph but, instead, must be carried out over the 
entire work shift to ensure that each miner using a PCDM was not 
personally overexposed. Simply stated, the PCDM would be turned ``ON'' 
when the miner enters the mine and remain operational while traveling 
to the MMU, during the entire time period spent working in the MMU, and 
while traveling back to the mine entrance, at which time the device 
would be turned ``OFF.'' Since most non-traditional work shifts in 
underground coal mines are less than 12 hours in length, the PCDM 
currently under development is being designed with sufficient battery 
capacity for one 12-hr work shift of operation.
    It should be pointed out that the duration of MSHA sample 
collection will continue to be limited to 480 minutes. The sampling 
device will be operated portal-to-portal and remain operational during 
the entire shift or for 8 hours, whichever time is less.
    Consistent with accepted industrial hygiene practice, proposed 
paragraph (d) will require the operator to use control filters when 
verifying the adequacy of the plan parameters under proposed Sec.  
70.206 or Sec.  70.220(c). A control filter is an unexposed filter of 
the same design as the filter cassette used for sampling, that is pre- 
and post-weighted on the same day as the filter cassettes used for 
verification sampling. MSHA first began using control filters in its 
enforcement program in May 1998 and continues this practice today. The 
reason for requiring their use by operators is to improve the accuracy 
in making weight-gain measurements of the exposed filter cassettes by 
eliminating the effect of differences in pre- and post-exposure 
laboratory conditions, or changes introduced during storage and 
handling of the filter cassettes. The control filter will be used to 
adjust the weight gain obtained on each exposed filter by subtracting 
any change in the weight of the control filter from the change in 
weight of each exposed filter. This is especially important since the 
filter cassettes to be used by operators will be pre- and post-weighed 
to the nearest microgram (0.001 mg). The other modification to the 
procedures for processing operator samples will be to discontinue the 
practice of truncating (to 0.1 mg) the recorded weights used in 
calculating dust concentrations. This means that Mine Safety Appliances 
Company (MSA), which upgraded its weighing equipment in 1996 and uses 
the same balance as MSHA's Coal Dust Processing Laboratory, will be 
permitted to follow MSHA and use all significant digits associated with 
the weighing capability of the balance (0.001 mg) when pre-weighing 
operator dust cassettes. These changes will enhance the proposed 
process of verifying the adequacy of plan parameters. This will also 
eliminate the need for operators to sample multiple shifts in order to 
obtain sufficient dust mass on the collection filter for quartz 
analysis. Since the use of a control filter adjusts for differences 
that may exist in laboratory conditions on the days of pre- and post-
weighing, it is no longer necessary to pre- and post-weigh the filter 
cassettes in the same laboratory. To ensure the precision and accuracy 
of the pre-weight of filters

[[Page 10812]]

used by the operator and federal mine personnel, MSHA will institute a 
program to monitor the daily production of filter cassettes weighed to 
the nearest microgram ([mu]g) by the manufacturer, MSA. The program 
will conform to MIL-STD-105D, which defines the criteria currently used 
to monitor the quality of pre-weighed filters used in the current 
operator bi-monthly sampling program.
    Since the control filter will be used to adjust the resulting 
weight gain obtained on each exposed filter cassette, the control 
filter must have the same pre-weight date as the filter cassettes to be 
used for sampling on the same shift. The pre-weight date is noted on 
the dust data card. Failure to follow these instructions will be cause 
for voiding the sampling results. Only one control filter will be 
required for each MMU per shift sampled. To prevent exposure to the 
mine environment, the plugs attached to the inlet and outlet side of 
the cassette must not be removed. Also, it is important that the 
control filter be exposed to the same time, temperature, and handling 
conditions as the ones that are used for sampling, i.e., carry the 
control filter in a shirt or coverall pocket while underground. While 
the control filter can be carried by any miner assigned to the MMU 
being sampled, it would be preferable if that miner performed the job 
of the DO. Finally, the control filter cassette must be kept together 
with the exposed samples after sampling and treated in the same manner 
as the exposed filters prior to being transmitted to MSHA. For 
processing purposes, the dust data card for the control filter must be 
marked with a large capital ``C'' for ``CONTROL'' in the middle of the 
card and enter a ``9'' in the ``Type of Sample'' box. The remaining 
items on the dust data card must be completed in the same manner as 
under the previous operator bimonthly sampling program. These 
procedures are identical to the ones followed by MSHA.
    To ensure that the plan parameters are designed to control 
respirable dust and are suitable to the conditions and mining system at 
the mine as required under Sec.  75.370(a) of this title, the proposed 
paragraph (e) prescribes minimum mining activity that must be ongoing 
during sampling, as well as the operating parameters for use of the 
engineering controls specified in the plan. Therefore, when sampling 
under proposed Sec.  70.206, Sec.  70.215 or Sec.  70.220(c), 
respirable dust samples must be collected on a production shift during 
which the amount of material produced by the MMU is at least equal to 
or exceeds the verification production level (VPL) as determined in 
accordance with Sec.  70.2. If the VPL is not achieved, the samples for 
that shift will be voided by MSHA. However, any sample that exceeds 
either verification limit or the applicable dust standard by any amount 
would be used to determine the equivalent concentration for that 
occupation, regardless of production. Also, if the MMU being sampled 
under proposed Sec.  70.215 is authorized to use PAPRs under special 
circumstances (see Sec.  70.212) and those circumstances prevent the 
operator from achieving the VPL, the sample(s) for that shift will be 
used to determine the equivalent concentration for the affected 
occupations.
    In addition to minimum production activity, limits must also be set 
on how much the specified engineering control parameters can deviate 
during sampling from the quantities specified in the ventilation plan. 
Failure to meet either criterion will undermine miner confidence in the 
ability of the approved plan parameters to effectively control 
respirable dust under the conditions at the MMU. Accordingly, paragraph 
(e) requires each operator to use only the engineering controls and 
other measures specified in the plan. Recognizing that engineering 
parameters such as air quantity and velocity and water pressure are 
subject to measurement error and can vary because they cannot be easily 
controlled with absolute precision, proposed Sec.  70.201(e) would 
permit the measured levels to be up to 115 percent of the minimum 
quantities specified in the plan.
    Since miners play an important role in the implementation and 
maintenance of the approved plan parameters, MSHA recognizes the need 
for miners to have full confidence in the sampling process used to 
approve and evaluate the continued adequacy of the plan parameters. 
Therefore, consistent with the underlying purposes of the Mine Act, 
proposed paragraph (f) would require the operator to provide affected 
miners and their representatives with an opportunity to observe any 
sampling required by this proposed rule. In addition, the operator 
would be required to give prior notice to miners and their 
representatives of the dates and times when the operator intends to 
conduct sampling. If the exposure of individual miners is monitored on 
a daily basis using a PCDM, the operator would be exempt from this 
requirement since all affected miners would already be aware that they 
were being monitored on a continuous basis. To make miner participation 
more effective, it is important that miners and their representatives 
are knowledgeable in those features of the sampling program specified 
in the proposed rule. This will enable them to make sound and 
knowledgeable judgements on the conduct of operator sampling under the 
proposed rule.
    While section 103(f) of the Mine Act requires the operator to 
compensate representatives of miners who accompany MSHA personnel 
conducting inspections, it would not apply to operator sampling as 
proposed, unless conducted on the same shift that MSHA chooses to 
monitor operator sampling. Therefore, unless accompanying MSHA 
personnel, section 103(f) would not authorize ``walkaround pay'' for 
time spent by a representative of miners observing the operator 
conducting sampling required by this part. MSHA believes that providing 
the representative of miners with an opportunity to accompany MSHA 
personnel monitoring operator sampling required by this part with no 
loss of pay is consistent with section 103(f) of the Mine Act. Under 
the guidance of the Interpretive Bulletin (43 FR 17546, April 25, 
1978), walkaround rights arise when: (1) An ``inspection'' is made for 
the purposes set forth in section 103(a), and (2) the inspector is 
physically present at the mine to observe or monitor safety and health 
conditions as part of direct safety and health enforcement activity.
    MSHA sampling required by this part would be unannounced and 
conducted to determine if the operator is in full compliance with both 
the operating conditions and sampling requirements of this part, as 
well as with all other health and safety standards. Consequently, the 
representative of miners would have the right to accompany the MSHA 
personnel with no loss of pay for the time during which the 
representative exercises this right.
    Existing paragraph (c) which requires the operator to submit, when 
requested by the district manager, the date and time when sampling 
required by this part will begin would be redesignated as paragraph 
(g). This requirement enables MSHA to monitor operator sampling on a 
case-by-case basis to verify compliance with both the operating 
conditions and sampling requirements of this part.
    The requirement that operators take corrective action during the 
time for abatement fixed in a citation for violation of Sec. Sec.  
70.100 or 70.101 specified in existing paragraph (d) of Sec.  70.201 
would be transferred to proposed Sec.  70.218(b)(2). The requirement 
that the operator sample each production shift until five valid samples 
are taken under existing

[[Page 10813]]

paragraph (d) would be removed since MSHA is proposing to revoke 
operator sampling requirements under existing Sec. Sec.  70.207 and 
70.208, and assume full responsibility for all compliance sampling.
Section 70.202 Approved Sampling Devices; Maintenance and Calibration
    In an effort to consolidate the requirements that address 
maintenance and calibration procedures of approved sampling devices, 
MSHA is proposing in Sec.  70.202(a) through (e) to retain the 
requirements in existing Sec.  70.203(a) and (b) and Sec.  70.204(a) 
through (e), with minor changes. These standards require the sampling 
device be maintained as approved and calibrated only by a certified 
person in accordance with MSHA Informational Report IR 1240 (1996).\8\ 
If using a PCDM under proposed Sec.  70.220, the device would be 
calibrated to the manufacturer's specifications. The process of 
certifying an individual for maintenance and calibration would remain 
unchanged. It would continue to require an individual to successfully 
complete the applicable MSHA examination. Scheduling information for 
MSHA training courses and examinations would be available from MSHA 
District Offices.
---------------------------------------------------------------------------

    \8\ On September 3, 1998, MSHA published a proposed rule in the 
Federal Register (63 FR 47123) requesting public comment on our 
intention to update the incorporation-by-reference in title 30 of 
the Code of Federal Regulations, Sections 70.204, 71.204, and 
90.204. The Agency allowed 60 days for public comment and received 
no comments, no requests for an extension of the comment period, and 
no requests for a public hearing. On August 10, 1999 the final rule 
was published and became effective on October 12, 1999 (64 FR 
43283).
---------------------------------------------------------------------------

    These standards require approved sampling devices to be calibrated 
at a flowrate of 2.0 liters of air per minute. They also establish the 
flowrate and testing and examination requirements for approved sampling 
devices. Careful examination and testing of sampling devices would 
continue to be required immediately prior to the start of a shift 
during which samples would be collected for purposes of this proposed 
rule. This would include testing the battery voltage and examining all 
external components of the sampling devices to be used. Any necessary 
external maintenance to assure the sampling devices are clean and in 
proper working condition should be performed at this time by a 
certified person. Temporary certification of persons provided under 
existing Sec.  70.203(b) would not be retained under the proposal.
    If using a PCDM in accordance with Sec.  70.220, the operator under 
proposed Sec.  70.202(f) would be exempt from the examination 
requirements of paragraphs (d)(1) through (d)(5) of this section. 
Instead, the operator would be required to follow the examination 
procedures recommended by the manufacturer or prescribed by MSHA and 
NIOSH for the particular device.
Section 70.203 Approved Sampling Devices; Operation; Air Flowrate
    Proposed Sec.  70.203(a) through (c) retains the operation and 
flowrate requirements for approved sampling devices in existing Sec.  
70.205(a) through (d), with minor changes. Since MSHA has defined an 
approved sampling device in revised Sec.  70.2 to mean a device 
approved in accordance with part 74 of this title, proposed paragraph 
(a) excludes reference to part 74. Similarly, for purposes of 
simplification, reference to Sec.  70.202 (Certified person; sampling) 
would be removed and, replaced by certified person as defined in 
revised Sec.  70.2.
    MSHA believes that the two on-shift examinations of sampling 
devices under proposed paragraphs (b)(1) and (b)(2), which are 
identical to the examinations required under existing Sec.  70.205(b) 
and (c), continue to be an important part of a reasonable and prudent 
sampling program. The first examination would be made by a certified 
person during the second hour after the sampling devices are placed in 
operation. This examination would assure that each sampling device is 
operating properly and at the proper flowrate. If the proper flowrate 
is not maintained, necessary adjustments in the flowrate would be made 
at this time by the person certified to collect samples. The second 
examination would be made during the last hour of operation of the 
sampling devices. If the proper flowrate is not maintained, the 
certified person is required to make a notation on the dust data card 
for that sample stating that the proper flowrate was not maintained. 
Because it is unclear where on the dust data card such a notation 
should be made, proposed paragraph (b) would require all notations 
regarding failure to maintain proper flowrate or other events occurring 
during sampling that may impact the validity of the sample to be made 
on the back of the dust data card.
    If using a PCDM under proposed Sec.  70.220, the operator would not 
be required to examine the device during the second and last hour of 
operation as required under paragraph (b) of this section. Instead, the 
operator would be required to follow the procedures recommended by the 
manufacturer or prescribed by MSHA and NIOSH to assure that the PCDM is 
operating properly and at the proper flowrate.
Section 70.204 Demonstrating the Adequacy of the Dust Control 
Parameters Specified in a Ventilation Plan; Verification Sampling
    Existing Sec.  75.370(a)(1) of this title requires the operator to 
develop and follow a mine ventilation plan that is designed to control 
methane and respirable dust. It further requires the plan to be 
suitable to the conditions and mining systems at the mine. Accordingly, 
a properly-designed mine ventilation plan continues to be the most 
reliable means for ensuring that the work environment in each MMU is 
free of excessive concentrations of respirable dust.
    MSHA recognizes that the operator has the legal responsibility for 
developing a ventilation plan that is designed to control respirable 
dust. Consequently, the operator has the obligation to demonstrate that 
the dust control parameters specified in the plan will effectively 
control respirable dust as required by Sec.  75.370(a)(1). Therefore, 
within 12 months after the effective date of this rule, each operator 
of an underground coal mine must have an approved ventilation plan in 
which the dust control parameters specified for each MMU have been 
verified to be adequate in controlling respirable dust. Proposed 
Sec. Sec.  70.205 through 70.208 set forth the specific steps an 
operator must follow to verify the adequacy of the plan parameters. To 
demonstrate adequacy, the operator would be required to collect valid 
respirable dust samples in accordance with proposed Sec.  70.206 or 
Sec.  70.220(c) if using a PCDM. Approval of the plan parameters for a 
particular MMU would be granted when these samples, called verification 
samples, demonstrate at a high level of confidence, in accordance with 
the limits specified in Table 70-1, the adequacy of the plan parameters 
in maintaining the equivalent concentration of respirable dust coal 
mine dust and quartz dust at or below the verification limits of 2.0 
mg/m3 and 100 [mu]g/m3, respectively.
Section 70.205 Verification Sampling; When Required; Time for 
Completing
    Proposed Sec.  70.205 specifies the various ways in which the 
process of verifying the adequacy of the dust control parameters for a 
MMU would be initiated. The operator would trigger the process by 
submitting a new ventilation plan under Sec.  75.370. This process 
would also be initiated if the district manager requires the operator 
to amend the plan parameters in a previously approved ventilation plan 
after determining, based on dust sampling results or other

[[Page 10814]]

evidence, that the dust control parameters in effect are no longer 
suitable to the current conditions at a particular MMU.
    Once the dust control parameters for a MMU have been verified as 
adequate, it would not be necessary to reverify the plan parameters as 
part of the MSHA six-month review under Sec.  75.370(g), unless the 
district manager determines these parameters are unsuitable for the 
current conditions at the MMU. However, the operator may be required to 
make changes to the parameters based on (1) results of the MSHA six-
month review, (2) excessive dust concentrations measured by either MSHA 
or operator monitoring samples, or (3) a new reduced applicable dust 
standard which is less than the highest respirable coal mine dust 
concentration that was previously used to verify the adequacy of the 
plan parameters. For example, if an operator was cited for exceeding 
the applicable dust standard when the approved plan parameters were 
being met or exceeded, the district manager may have cause to question 
the adequacy of the previously-approved dust control parameters.
    Also, depending on sampling results and production records, if the 
production exceeds the VPL specified in the plan, the district manager 
may require the operator to verify the plan parameters at the higher 
production level. For example, suppose the VPL is 10,000 tons and all 
five concentration measurements taken during MSHA sampling exceed the 
applicable dust standard on a shift for which the production is 12,000 
tons. Then, if the production records indicate that the operator has 
exceeded the VPL on more than 33 percent of all production shifts 
during the previous six months, that evidence would demonstrate that 
the VPL specified in the plan is no longer valid. The district manager 
would then require the operator to verify the plan parameters under 
current operating conditions.
    Under the proposed rule, the operator would be required to verify 
the adequacy of the dust control parameters for each MMU within 45 
calendar days after obtaining provisional approval from the district 
manager. This should be ample time for an operator to demonstrate the 
adequacy of the plan parameters, even when starting up a new MMU, such 
as a longwall panel. Should an operator experience difficulty in 
establishing the desired VPL or encounter other unexpected breakdowns 
or unforseen circumstances affecting the operational status of a MMU 
after obtaining provisional approval, the district manager may grant an 
operator an extension of up to 30 days to complete verification 
sampling. Before receiving provisional approval, the operator may be 
required to modify the plan parameters if the district manager 
determines that the particular parameters are inadequate or unsuitable 
for the current conditions in the MMU. If provisional approval is not 
granted, the operator may not operate the affected MMU.
    Under the proposed rule, the adequacy of all previously approved 
dust control parameters would need to be verified by the operator 
within 12 months after the final rule becomes effective. Before 
submitting these plan parameters to the district manager for review and 
approval to commence verification sampling, proposed paragraph (b) 
would require the operator to provide additional information. The 
additional information is described under revised Sec.  75.371(f) of 
this proposed rule. The operator will be permitted to operate a MMU 
under the previously approved dust control parameters until the amended 
plan parameters are either provisionally approved or denied.
    To minimize delays in the verification process, MSHA will develop 
and issue appropriate compliance guides and provide adequate training 
on the new rule prior to its implementation. MSHA will also be 
available to provide guidance to individual mine operators once the 
rule becomes effective. The Agency intends to make every effort to 
ensure an orderly and efficient transfer from the previous plan 
approval process to the new process of validating the adequacy of dust 
control parameters for each MMU prior to implementation.
Section 70.206 Verification Sampling; Procedures for Sampling
    This proposed section establishes the sampling procedures that each 
operator would follow when conducting verification sampling. Described 
are the specific occupations and areas to be monitored in a MMU, and 
the operation and placement of each sampling device during sampling. 
The specific operating conditions under which these occupations and 
areas would be sampled are discussed under Sec.  70.201. These will be 
covered again for the benefit of the reader.
    Proposed paragraph (a) would require the operator to sample 
specific occupations assigned to a MMU. These occupations were selected 
because, based on MSHA experience over the past 20 years, miners 
required to work in those occupations are likely to be exposed to the 
greatest respirable dust concentration and, consequently, would be at 
significant risk of overexposure. Therefore, the operator would be 
required to sample the environment of: (1) The DO in accordance with 
proposed paragraphs (d)(1) through (d)(10), which are identical to 
existing Sec.  70.207(e)(1) through (e)(10); (2) the roof bolter 
operator(s) (occupation codes--012, 014 or 046); (3) the longwall jack 
setters (occupation code--041); and (4) any other occupation that the 
district manager may designate for sampling after reviewing the 
operator's plan parameters.
    Unless otherwise directed by the district manager, when an operator 
samples a longwall MMU, the DO sample required by this part would be 
collected by placing the sampling device on the miner who works nearest 
the return air-side of the longwall working face. Since 1987, this work 
location has been assigned the 060 occupation code by MSHA for sampling 
and tracking purposes in accordance with existing Sec.  70.207(e)(7). 
Therefore, when sampling the 060 DO, the sampling device would remain 
at all times with the miner working nearest the return air-side of the 
longwall face. If individual miners rotate out of the DO position 
during sampling, as is the common practice at some operations, the 
sampling device must be transferred to and worn by the new miner 
rotated into the DO position. For example, if all other miners are 
working upwind of the tailgate-side longwall operator, the miner 
performing that particular job becomes the DO and wears the sampling 
device since that individual is working nearest the return air-side of 
the longwall face. However, if during the shift being sampled another 
miner, such as the face mechanic, travels past the tailgate-side 
longwall operator toward the return air-side, the face mechanic would 
then become the DO and must wear the sampling device for the period of 
time that individual works nearest the return air-side of the longwall 
face. When the face mechanic returns upwind of the longwall operator, 
the sampling device must then be transferred back to the longwall 
operator, as that individual will now be the miner working nearest the 
return air-side.
    This is compatible to sampling any other DO, whether it is the 036 
DO (continuous miner operator) or the 044 DO (tailgate-side longwall 
operator). The sampling device must remain at all times in the 
environment of the DO and not with the individual miner, regardless of 
how many miners work in that location during the shift. Sampling the DO 
in this manner preserves the long-standing high-risk occupation

[[Page 10815]]

sampling concept which the Agency adopted in 1970.
    Under these procedures the sampling device must remain in the 
environment of the miner who works nearest the return air-side of the 
longwall working face. However, in certain circumstances, MSHA may not 
require transfer of the sampling device if the amount of time a 
particular miner spends inby or downwind of the DO is known to be 
infrequent and of short duration, limited to 20 minutes or less. 
However, transfer of the sampling device is required if the same miner 
travels inby the DO routinely during the shift.
    There are other ways to reduce the number of times that a sampling 
device needs to be transferred from one miner to another during a 
shift. This depends on the particular mining practices of the operator. 
By fully utilizing the operational capabilities designed into 
currently-employed longwall equipment or altering the mining cycle, the 
need for miners to work routinely inby the shearer can and should be 
minimized, thereby reducing the number of necessary pump transfers, and 
the potential for miners to be overexposed to respirable dust. Another 
approach has been used successfully at longwall MMUs employing a type 
of water-spray system called ``shearer-clearer.'' This involves 
limiting the movement of miners to a certain region or distance inby of 
the shearer. In some instances this distance can reach 40 feet inby if 
samples indicate dust levels are similar to the levels in the 
environment of the tailgate-side shearer operator (Occupation code 
044).
    If a properly designed shearer-clearer system is installed and 
maintained, it is very effective in confining the shearer-generated 
dust to the face for some distance downwind of the shearer and prevents 
migration to the walkway where miners are located. Therefore, miners 
who are required to spend time inby the shearer can be protected from 
exposure to excessive dust levels if their work is limited to this 
particular area. This area, however, is normally established through 
sampling on a mine-by-mine basis. The area can vary depending on the 
quantities and velocities of air delivered to the longwall face, type 
of cut sequence, water flow rates and spray pressures, and tonnage 
produced.
    If any of these approaches are not suitable or if the miner working 
furthest downwind refuses to wear the sampling device for any reason, 
the proposed rule provides for the placement of the sampling device in 
a specified location on the return side within 48 inches of the corner 
of the longwall face, which MSHA has designated as the 061 DO. Placing 
the sampling device at this location is comparable to placing the 
sampling device on the continuous mining machine within 36 inches inby 
the normal work position of the machine operator. It should be noted, 
however, that since dust concentrations at this location are typically 
the highest, no longwall MMUs are currently submitting bimonthly 
samples taken at the 061 DO.
    The proposed approach, which involves sampling the ``high risk 
occupation,'' currently referred to as the DO, is not new and has been 
in use since inception of the mandated sampling program in 1970. This 
sampling approach is designed to monitor the mine atmosphere with the 
greatest concentration of respirable dust exposure, in the areas where 
miners are working during their shift, to prevent excess exposure of 
miners to respirable coal mine dust. The goal has never been to measure 
the exposure of an individual miner for the duration of a shift, but 
rather to determine if the mine atmosphere in the active workings is 
free of excessive concentrations of respirable dust in order to protect 
each miner required to work in that environment.
    Based on the various dust generating sources and the manner in 
which the face is ventilated, the return air-side of a longwall face is 
the area on a longwall MMU with the greatest concentration of 
respirable dust. Accordingly, since miners are required to work in this 
area, operators are required to maintain the mine atmosphere in this 
area or location in compliance with the applicable dust standard on 
each shift. By doing so, it can be concluded that other miners in less 
risky occupations are protected from excessive dust concentrations. 
While these measurements will not show a particular miner's dust 
exposure, the results will indicate if the air that miners are 
breathing is in compliance with the applicable dust standard. The 
objective of the proposed sampling scheme is to control the 
concentration of respirable dust in the workplace. The method of 
sampling the DO on a longwall MMU was determined to be reasonable and 
consistent with the Mine Act in American Mining Congress v. Marshall, 
671 Fed 12151 (10th Cir. 1982). MSHA believes that the method of 
sampling being proposed will effectively serve the health protection 
goal of achieving and maintaining good air quality in each MMU. 
Therefore, the long-standing practice of sampling the DO in each 
longwall MMU or any other DO would be continued under the proposed 
rule.
    Since the objective is to verify the adequacy of the dust control 
parameters in effect at a MMU, proposed paragraph (b) would require 
sampling devices to be turned ``ON'' when the production crew arrives 
at the MMU to be sampled, regardless if any actual mining is taking 
place, and not at the portal as required in existing Sec.  70.201(b) 
for bimonthly sampling. The operator would continue to examine each 
sampling device at least twice during the sampling shift in accordance 
with proposed Sec.  70.203(b)(1) and (2). Each sampling device would 
remain operational during the entire shift that the production crew 
remains in the MMU, regardless of the number of hours worked. The 
sampling devices would be turned ``OFF'' at the end of the shift as the 
production crew, assigned to the occupation(s) being sampled, exits the 
MMU to travel back to the mine portal.
    Each operator would be required to use one control filter for each 
shift of sampling as required by proposed Sec.  70.201(d). As explained 
earlier, the control filter will be used to adjust the weight gain 
obtained on each exposed filter by subtracting any change in the weight 
of the control filter from the change in weight of each exposed filter. 
Its use in accordance with Sec.  70.201(d) will enhance the decision-
making process involving the approval or denial of the dust control 
parameters by the district manager.
    To qualify as a valid sample for verification purposes, the amount 
of material produced by the MMU during the shift being sampled must 
equal or exceed the VPL as required by proposed Sec.  70.201(e). If the 
VPL is not achieved, the sample(s) will be voided by MSHA. However, any 
sample that exceeds either verification limit or the applicable dust 
standard by any amount would be used to determine the equivalent 
concentration for that occupation, regardless of production.
    Proposed Sec.  70.201(e) also requires the operator to utilize only 
the dust control parameters that were provisionally approved by the 
district manager. Recognizing that engineering parameters such as air 
quantity and velocity and water pressure are subject to measurement 
error and cannot easily be controlled with absolute precision, MSHA 
would allow the measured levels to be up to 115% of the quantities 
specified in the plan.
    If a measured level exceeds the corresponding quantity specified in 
the plan by more than 15 percent, the operator would have the option to 
either (1) adjust the engineering parameter(s) to what is specified in 
the plan before beginning verification sampling or (2)

[[Page 10816]]

make no adjustment to the parameter(s) prior to verification sampling. 
Under the second option, final approval of the plan parameters would be 
contingent on the operator incorporating in the plan the maximum 
quantities of parameters measured during verification sampling. If 
verification samples were collected on a shift when a plan parameter 
exceeded 115 percent of the quantity specified in the plan, then 
(assuming none of the verification samples exceeded the critical 
values) that parameter quantity, as measured, would be incorporated 
into the plan parameters ultimately approved by the district manager.
    If an operator chooses to sample multiple shifts, they would not 
have to be consecutive shifts as under the previous bimonthly sampling 
program. The operator would be required to submit for processing all 
samples collected by the operator, regardless of the operating 
conditions under which verification sampling was conducted.
    The number of shifts that the operator would need to sample to 
verify the adequacy of the plan parameters depends on two factors: 
First, the actual operating conditions in effect during the shift being 
sampled; and, second, the individual sample results. As discussed 
earlier, for a respirable dust sample to be valid for verification 
purposes, the amount of material produced by the MMU must equal or 
exceed the VPL, and the dust control parameters must be at levels not 
exceeding 115 percent of the quantities specified in the plan. 
Therefore, the number of shifts depends largely on how quickly and 
consistently the operator would be able to achieve these operating 
conditions. The operator may need to sample several shifts before the 
production level on any single shift qualifies for verification 
purposes. The operator could verify the adequacy of the plan parameters 
based on this single shift--but only if all sample results are at or 
below the critical values listed in Table 70-1 that correspond to the 
number of shifts sampled. This would demonstrate the adequacy of the 
plan parameters at a high level of confidence. If any of the sample 
results exceed the appropriate critical value, then the operator would 
need to collect verification samples taken on one to three additional 
shifts, depending on the concentrations measured on those shifts. Since 
these additional shifts would also need to meet the production 
criteria, and use only the dust control parameters specified in the 
plan, some operators would need to sample a total of more than four 
shifts.
    Assuming that the operator makes no special effort to meet the VPL 
during verification sampling, there is a 67-percent probability that a 
randomly selected production shift would not meet the VPL. 
Consequently, if the operator made no special effort to achieve the 
desired production, there would be a 13-percent chance the operator 
would need to sample more than five shifts and a 1.7-percent chance the 
operator would have to sample more than 10 shifts.\9\ On the other 
hand, again assuming no special production effort, there would be a 98-
percent chance the operator would need 10 or fewer shifts and a 70-
percent chance that the operator would need to sample three or fewer 
shifts.\10\ This assumes that the sample results for each shift do not 
exceed the critical value corresponding to the number of shifts 
sampled. If the operator should make a concerted effort to achieve the 
VPL on the sampled shifts and meet the other criteria, then sampling of 
fewer shifts would be needed to verify the adequacy of the dust control 
parameters.
---------------------------------------------------------------------------

    \9\ Assuming no special production effort, the probability of 
needing more than n shifts to be sampled before meeting the minimum 
production level required to verify the plan: P(Xn)= 
(.667)\n\; for example, the probability of more than 10 shifts being 
needed, P(X) 10) = (.667)\10\ = 1.7 percent.
    \10\ Assuming no special production effort, the probability of 
needing n or fewer shifts to be sampled before meeting the minimum 
production level required to verify a plan: P(X<=n)=1-
P(Xn); for example, the probability of 10 or fewer shifts 
being needed, (1-(.667)\10\) = 98 percent.
---------------------------------------------------------------------------

Section 70.207 Approval of Dust Control Parameters by District Manager; 
Revocation of Approval
    This proposed section establishes the criteria or ``critical 
values'' that the district manager would use to determine whether the 
operator's dust control parameters should be approved or denied. These 
critical values, which differ according to the number of shifts sampled 
by the operator, are listed in Table 70-1. Appendix A explains how the 
critical values were derived. When verification sample results do not 
exceed the applicable critical values, the district manager can be 
confident that the dust control parameters in use during verification 
sampling successfully prevented overexposures at the sampled locations.
    The district manager would approve the operator's plan parameters 
when the amount of material produced is at or above the VPL, the 
parameters and other measures in place during verification sampling do 
not exceed 115% of the quantities specified in the plan, and no 
equivalent concentration measurement exceeds the applicable critical 
values corresponding to the number of shifts sampled.

      Table 70-1.--Critical Values for Determining Compliance With
                          Verification Limits.
 [The result of each verification sample collected must be less than or
                equal to the applicable critical values.]
------------------------------------------------------------------------
                                                 Critical      Critical
                                                 value for    value for
    Number of shifts meeting criteria for        coal mine   quartz dust
            verification sampling                dust (mg/     ([mu]g/
                                                   m\3\)        m\3\)
------------------------------------------------------------------------
1............................................          1.71           87
2............................................          1.85           93
3............................................          1.93           97
4 or more....................................          2.0           100
------------------------------------------------------------------------

    The proposed criteria would allow the district manager to base 
approvals on a reasonably small number of sampled shifts, while 
maintaining a high level of confidence that approved dust control 
parameters adequately prevent excessive dust concentrations on 
individual shifts.
    The following two examples illustrate how the district manager 
would apply the proposed criteria or ``critical values'' to determine 
if the operator's plan parameters for a MMU should be approved.

    Example 1: Suppose valid verification samples were taken on two 
shifts. According to Table 70-1, the district manager would approve 
the operator's dust control parameters if all coal mine dust and 
quartz measurements obtained on the two shifts were less than 1.85 
mg/m\3\ and 93 [mu]g/m\3\, respectively. On the other hand, if one 
roof bolter sample indicated a quartz concentration of 95 [mu]g/
m\3\, then the district manager would not approve the operator's 
plan parameters based on these two shifts alone. Instead, at least 
one additional shift of sampling would be needed. Valid verification 
samples from only one additional shift would be sufficient if none 
of the coal mine dust measurements on that shift exceeded 1.93 mg/
m\3\, and none of the quartz measurements exceeded 97 [mu]g/m\3\.
    Example 2: Suppose valid verification samples were taken on four 
or more shifts. The district manager would approve the operator's 
plan parameters as proposed if no measurement taken over those four 
or more shifts exceeded 2.0 mg/m\3\ of coal mine dust or 100 [mu]g/
m\3\ of quartz dust.
    The district manager may revoke approval of the dust control 
provisions if either MSHA samples or operator samples collected in 
accordance with proposed Sec.  70.215 indicate that miners are being 
overexposed to respirable coal mine dust.
Section 70.208 Follow-up Action When Either Verification Limit Is 
Exceeded
    This proposed section would require the operator to take certain 
actions when a verification sample exceeds either the respirable coal 
mine dust or quartz verification limit. The operator

[[Page 10817]]

would be required to stop verification sampling, provide approved 
respiratory equipment, identify the cause of the high dust 
concentration, and take corrective action to prevent miners from being 
overexposed on subsequent shifts.
    When the operator receives notification from MSHA that a 
verification sample exceeded either verification limit, the operator 
must stop sampling and immediately make approved respiratory equipment 
available to affected miners in accordance with Sec.  70.300. The use 
of respiratory equipment should be encouraged until the operator 
determines the cause of the overexposure and takes corrective measures. 
If deficiencies are identified in the operator's dust control program, 
appropriate corrections must be made under proposed paragraph (b) to 
lower dust concentrations in the work environment of the affected 
occupation or location to a level no greater than the applicable 
verification limits.
    MSHA recognizes that, given the rigorous nature of the verification 
test conditions, such as requiring higher production levels to be 
maintained and the application of stringent approval criteria, some 
failures will occur. If some attempts prove to be less than successful, 
it would not necessarily be due to the lack of good faith effort on the 
part of the operator, but could be due to the inability to predict 
accurately the effectiveness of particular dust control parameters 
under the proposed test conditions. For example, assume the VPL 
proposed is significantly higher than that which has been recorded 
during previous sampling inspections. In this instance, it would be 
difficult to predict in advance that the proposed dust control 
parameters would be effective unless the VPL was more representative of 
the previous production levels. Therefore, MSHA is proposing not to 
cite the operator when samples exceed the verification limits. However, 
an operator would be cited under proposed paragraph (b) of this section 
for failure to take action required to address the cause of the 
excessive dust levels once notified of the results of verification 
sampling. This is consistent with the Dust Advisory Committee's 
recommendation that:

    MSHA should not issue citations for violation of the applicable 
dust standard based on operator verification sampling. Operator 
inaction to protect miners where dust values are in excess of the 
PEL should be citable by MSHA.''

    The operator would also be required under proposed paragraph (c) to 
document the corrective actions taken and submit this information to 
the district manager within five days of receiving MSHA notification 
that one or both of the verification limits were exceeded. The 
documentation must describe the specific corrective measures taken and 
the manner that these measures would be used to prevent overexposures 
on subsequent shifts, including the proposed changes in dust control 
parameters. The operator would be encouraged to seek technical 
assistance from the district manager to help in determining what 
additional measures are reasonably likely to help in meeting the 
verification limits.
    The district manager would notify the operator and the 
representative of miners if the proposed revisions to the plan are 
provisionally approved and whether the operator should either resume or 
initiate verification sampling in accordance with Sec.  70.206. The 
district manager may require the operator to make additional changes to 
the plan parameters based on the results of verification sampling 
before the operator begins the verification sampling process over 
again. If no additional changes are required by the district manager, 
the operator would be instructed to resume the verification process by 
continuing the sampling from the point at which it was stopped.
    The district manager would determine whether the operator should 
either resume verification sampling or start plan verification anew on 
a case-by-case basis. MSHA would not necessarily require the operator 
to revise the plan parameters nor require the verification process to 
start over again because a valid sample exceeded the verification limit 
by a small amount, such as 0.05 mg/m\3\, unless the district manager no 
longer felt confident in the ability of the plan parameters to 
effectively control respirable dust under the proposed operating 
conditions. The decision to resume sampling to verify the adequacy of 
the current plan parameters or start over again with totally revised 
plan parameters would be based on the information the operator provides 
regarding the cause of any excessive dust concentration measurements 
and the steps taken to prevent similar occurrences in the future. For 
example, suppose the concentration measurements are excessive due to a 
deviation in the operator's established operating procedures. It should 
be possible for the operator to prevent this from occurring in the 
future without requiring changes in the dust control parameters. If the 
district manager finds this to be the case, and concurs with the 
operator's proposed action to prevent similar occurrences, the operator 
would be directed to resume verification sampling. However, if the plan 
parameters are found to be inadequate for the proposed operating 
conditions and the operator was notified to upgrade the parameters, the 
operator would be instructed to start the verification process over 
again.
Section 70.209 Use of Supplementary Control Measures; Types and 
Conditions for Use; Request for Approval
    This proposed section would require the operator to take certain 
actions when verification samples exceed either verification limit 
after the operator implemented all feasible engineering or 
environmental controls. It would permit an operator to use approved 
powered air-purifying respirators (PAPRs), administrative controls, or 
a combination of both, after MSHA has determined that further reduction 
of dust levels cannot be reasonably achieved using accepted engineering 
controls. The decision-making process for determining whether feasible 
engineering controls should be augmented by supplementary controls 
(personal protective equipment and/or work practice controls) to 
maintain the personal work environment of the affected miners at a safe 
exposure level will consider the various factors involved in each 
specific situation. Some of the factors to be taken into account 
include: (1) The severity and magnitude of the exposure; (2) number of 
affected miners, their job location and assignment; (3) types and 
location of dust-generation sources; (4) range of effectiveness and 
reliability of the implemented engineering controls; (5) availability, 
suitability, reliability, and cost of other feasible engineering 
controls; (6) operational conditions such as the method of mining, 
mining height, etc.; (7) compliance history; (8) effectiveness and 
reliability of supplementary control measures; (9) concerns of 
individual miners and their representatives; and (10) ability to 
measure and ensure the adequacy of exposure control.
    Section 202(h) of the Mine Act does not prohibit the use of PAPRs 
and administrative controls under the specific circumstances set forth 
in the proposed rule. These measures would be used only as 
supplementary controls and not as a substitute or replacement for 
engineering control measures in the active workings. The use of these 
supplementary control measures under the conditions of use set forth in 
the proposed rule will enhance the level of health protection for 
miners by preventing overexposures on all shifts.

[[Page 10818]]

The combination of engineering and supplementary controls will provide 
reliable and effective exposure control when used in accordance with 
the approved plan provisions.
    Consistent with the Mine Act and the Dust Advisory Committee's 
recommendation, engineering controls continue to be recognized as the 
primary means to control exposure to respirable dust under this 
proposed rule. Therefore, if verification samples for a MMU continue to 
exceed either verification limit after implementing all feasible 
engineering controls, including such measures as required by the 
district manager, the operator must continue to use these control 
measures to reduce the concentration of respirable dust as low as 
possible.
    MSHA believes that it is feasible to control respirable dust to an 
acceptable level as required by Sec.  75.370(a)(1) at most non-longwall 
operations using available engineering controls. Currently, over 90 
percent of the approximately 720 continuous miner operations employ 
extended cut techniques and, therefore, are being operated remotely. As 
a result, the continuous miner operator, the occupation normally 
identified as the DO, is no longer required to work near the face area 
where material is being extracted and respirable dust generated. 
Likewise, roof bolting machines, a major generator of respirable quartz 
dust on continuous miner MMUs, are now required to be equipped with 
suitable drill dust controls. Under Sec.  72.630 of this title, drill 
dust must be controlled by either permissible dust collectors, by 
water, water with a wetting agent, by ventilation, or by any other 
method approved by MSHA. However, the Agency also recognizes that some 
non-longwall MMUs continue to have difficulty maintaining consistent 
compliance with reduced standards even at production levels that are 
significantly lower than the proposed VPL because of the high quartz 
content of the adjacent roof rock, which is drilled to install roof 
bolts, or of the coal seam being mined.
    With regard to mining operations employing the longwall mining 
method, MSHA recognizes that technological advances have boosted 
longwall production to record levels. According to MSHA data, the 
average production reported by operators during bimonthly sampling of 
longwall MMUs has increased over 6 fold between 1980 and 2002, from 890 
to 5500 tons/shift. Unfortunately, as discussed in section III.D. of 
the preamble, dust control technology has not kept pace, rendering 
available, acceptable controls less effective, which increases the 
miner's risk of being overexposed on any given shift. Given the state 
of longwall dust control technology, the engineering controls currently 
available may not be effective in achieving and maintaining continuous 
compliance at certain locations along the longwall face such as 
downwind of the longwall operator (occupation code--044) at some high-
production longwall MMUs. If the operator believes that all feasible 
engineering controls have been installed, maintained, and operated as 
specified in the ventilation plan, the operator may submit a written 
request to MSHA's Administrator for Coal Mine Safety and Health, asking 
for authorization to augment the implemented engineering controls with 
supplementary controls to maintain the personal work environment of the 
affected miners at a safe exposure level and to achieve compliance with 
the verification limits and Sec. Sec.  70.100 and 70.101. If such a 
request is made, a copy must be provided to the representative of 
miners and posted on the mine bulletin board in accordance with 
proposed Sec.  70.217(b)(3) at the time it is submitted to MSHA.
    When the Administrator receives such a request, guidance would be 
immediately solicited from a panel of experts specifically established 
to address such matters. Members of this panel would have extensive 
knowledge in respirable dust control and would represent the following 
organizations within MSHA: Technical Support, Division of Health, the 
MSHA District having jurisdiction over the mine making the request, and 
another MSHA District. In some cases, MSHA may solicit advice from 
NIOSH, an Agency with significant experience in dust control. As part 
of their deliberations and on a case-by-case basis, the expert panel 
may visit the mine to observe various controls in operation. This panel 
will also consider all comments MSHA receives from the representative 
of miners, as well as individual miners, and provide copies of these 
comments to the operator upon request. Any recommendations reached by 
this panel would be based on the (1) review of all the facts gathered, 
(2) consideration of the various factors involved in each specific 
situation as outlined above, (3) their combined practical and technical 
experience in dust control, and (4) sound engineering judgement.
    Recognizing the urgency of such a request, the Administrator would 
either approve or deny the operator's request within 30 calendar days 
or as soon as practical after receiving the request. If approval is 
denied, the operator will be notified in writing of the specific 
reasons for disapproval. If approval is granted, the operator would be 
permitted to use either PAPRs approved by NIOSH under 42 CFR 84 and by 
MSHA under part 18 of this title, administrative controls, or a 
combination of both, as supplementary controls to protect those miners 
assigned to occupations that continue to exceed either verification 
limit, provided the operator meets the conditions specified in 
Sec. Sec.  70.210 and 70.211 or Sec. Sec.  70.213 and 70.214 of this 
part.
    If the affected occupation involves the 060 occupation, the 
operator would also be informed that the DO would be changed from the 
060 to the 044 occupation, or another occupation designated by the 
district manager depending on how the particular longwall MMU is 
ventilated. While it may be difficult to lower the dust levels to the 
applicable dust standard in the environment of some miners working on 
the longwall face under certain operating conditions, MSHA believes 
that, using available engineering controls, an acceptable work 
environment can be provided for the tailgate-side longwall operator 
(Occupation code--044) and other miners on a continuing basis. 
Therefore, unless demonstrated otherwise through verification sampling, 
the operator would be required to maintain the environment of the new 
044 DO at or below the verification limits or below the applicable dust 
standard using engineering controls. This should have a significant 
effect on the quality of the mine atmosphere downwind of the 044 DO 
where miners, wearing PAPRs or under administrative controls, are 
required to work.
    Under the proposed rule, the operator would be permitted to 
continue to use supplementary controls to reduce dust exposure of 
individual miners assigned to specific occupations until such time when 
other feasible engineering controls become available and are 
implemented or until the district manager revokes the operator's 
approval to use supplementary controls for failure to comply with the 
requirements of proposed Sec.  70.211(b) or Sec.  70.214(b).
    As discussed above, MSHA will continue to require that all feasible 
engineering controls be installed. While the proposed rule provides for 
expanded use of supplementary controls, such control measures should 
only be used as an interim method of protection since their 
effectiveness remains secondary to that of engineering controls.

[[Page 10819]]

Section 70.210 Through 70.212

Use of Powered Air-Purifying Respirators (PAPRs)

    These sections would establish the requirements for using PAPRs as 
a supplementary control to maintain the personal work environment of 
the affected miners at a safe exposure level when MSHA has determined 
that further reduction in respirable dust concentrations cannot be 
achieved using all feasible engineering or environmental controls or 
under special circumstances.
Section 70.210 Powered Air-Purifying Respirators (PAPRs); Requirements 
for Approval
    If the operator chooses to use PAPRs as a supplementary control 
measure, the operator must submit a revision to the ventilation plan to 
the district manager within five days of receipt of MSHA's written 
approval in accordance with proposed Sec.  70.209(b). The proposed 
revision would specify the feasible engineering controls that are 
capable of (1) reducing the concentration of respirable dust as low as 
achievable in every occupational environment where a PAPR is required 
to be worn, and (2) maintaining other occupational environments in the 
MMU at or below the verification limits. The proposed revision must 
reflect the engineering controls that were in use at the time that the 
determination was made by MSHA to permit the use of supplementary 
controls.
    In addition to specifying all feasible engineering controls to be 
used, proposed paragraph (a)(2) would require the operator to develop a 
written PAPR protection program which meets the requirements of Sec.  
72.710 and incorporates the following information: (1) The protection 
factor as determined in accordance with proposed Sec.  70.2 that would 
be assigned to the affected MMU; and (2) the specific occupation(s), 
work locations or tasks where PAPRs must be worn by the affected 
miners. A model PAPR protection program to guide the operator in 
developing a mine-specific program that complies with the requirements 
of this section is described in Appendix B. The district manager may 
require the operator to modify the PAPR protection program before 
granting provisional approval of the proposed plan revision.
    Also, consistent with the NIOSH Criteria Document and section 
101(a)(7) of the Mine Act, proposed paragraph (a)(3) would require the 
operator to post warning signs with the statement ``RESPIRATORY 
PROTECTION REQUIRED IN THIS AREA'' in locations where PAPRs must be 
worn. Since the presence of excessive dust concentrations is not 
readily discernible, MSHA believes that the use of warning signs is 
necessary to protect miners. The posting of warning signs is an 
appropriate vehicle to inform or remind miners, regardless of their 
familiarity with the workplace environment, that they are entering a 
high dust area where the use of PAPRs is mandatory. The Agency 
recognizes that Sec.  75.370(e) requires that operators instruct 
persons affected by a revision to the ventilation plan prior to 
implementation. Section 75.370(f)(3) also requires approved revisions 
to be posted on the mine bulletin board for the period that the plan is 
in effect. MSHA is soliciting comments on whether it should require the 
posting of warning signs when PAPRs must be worn, or should it be 
optional and left to the discretion of the operator.
    Proposed paragraph (b) requires the operator to verify, in 
accordance with proposed Sec.  70.206(b) through (e), the adequacy of 
the revised plan parameters, incorporating the use of PAPRs, within 30 
calendar days of obtaining provisional approval from the district 
manager. Accordingly, the operator would be required to collect 
verification samples in the environment of (1) the occupation(s) where 
PAPRs must be worn by miners assigned to work in those job positions, 
(2) the DO, and/or (3) other occupation(s) that may be designated by 
the district manager.
Section 70.211 Powered Air-Purifying Respirators (PAPRs); Approval and 
Conditions for Continued Use; Revocation of Approval
    This proposed section establishes the criteria that the district 
manager would use to determine whether the operator's proposed plan 
revision incorporating the use of PAPRs should be approved. As 
previously discussed under proposed Sec.  70.207, approval of the 
proposed revision would depend on the results of verification sampling 
and the operating conditions in effect for each sample.
    The district manager would approve the operator's revised plan 
when: (1) The amount of material produced is at or above the VPL, the 
parameters and other measures in place during verification sampling do 
not exceed 115% of the quantities specified in the plan, and no 
equivalent concentration measurement exceeds the critical values listed 
in Table 70-1 that correspond to the number of shifts sampled; and (2) 
the revision incorporates the dust control parameters used during 
verification sampling.
    To account for the expected workplace level of respiratory 
protection provided the wearer of the PAPR, the equivalent 
concentration measurement must be adjusted further in accordance with 
Sec.  70.2. This requires the equivalent concentration to be divided by 
the protection factor (PF) specified in the PAPR protection program for 
the particular mechanized mining unit (MMU). The PF represents the 
minimum reduction in dust concentration that a respirator would be 
expected to provide. In the absence of a direct measure of the dust 
concentration inside the PAPR (in the miner's personal work 
environment) while under the conditions of the workplace, the adjusted 
equivalent concentration represents a surrogate measure of the 
respirable dust concentration inside the PAPR facepiece to which the 
wearer is exposed. Since the PFs assigned to MMUs under this proposed 
rule incorporate a margin of safety, the resulting equivalent 
concentration measurement represents a conservative estimate of the 
dust concentration in the miner's breathing zone.
    For example, assume that a MMU, which was assigned a PF = 3, was 
sampled one shift and the concentration measurement for the sampled 
occupation under a PAPR protection program is 3.54 mg/m3 for respirable 
coal mine dust and 174 [mu]g/m3 for respirable quartz dust. 
Under the definition of ``equivalent concentration,'' these 
measurements are divided by 3, which yields an equivalent concentration 
of 1.18 mg/m3 [3.54 mg/m3/3] for respirable coal 
mine dust and 58 [mu]g/m3 [174 [mu]g/m3/3] for 
respirable quartz dust to which the miner assigned to that occupation 
is exposed. If no other valid equivalent concentration measurement 
obtained on one shift exceeds 1.71 mg/m3 or 87 [mu]g/
m3 according to Table 70-1, the district manager would 
approve the revised plan incorporating the use of PAPRs.
    MSHA believes that this strategy provides far more health 
protection to miners than is available under current regulations, which 
only requires operators to make available approved respiratory 
equipment to miners when exposed to excessive dust concentrations. 
There is no requirement that miners actually wear the respirator when 
issued. Under the proposed rule, not only must PAPRs be worn at all 
times but must also conform to specific requirements consistent with an 
acceptable respiratory protection program.
    Proposed paragraph (b) establishes the requirements for the 
continued use of

[[Page 10820]]

PAPRs as a supplementary control. To continue to use PAPRs and operate 
under the same conditions that were in effect during verification 
sampling, the operator would be required to comply with the approved 
revised plan parameters on each production shift, in particular, the 
provisions of the PAPR protection plan. MSHA believes that the 
effectiveness of a PAPR is dependent upon proper training and continued 
maintenance, which are critical elements of an acceptable PAPR 
protection program. Necessary maintenance includes examining the PAPR 
for defects prior to use, charging the batteries properly, and 
appropriate replacement of parts including, but not limited to, the 
filter elements, visors, batteries, blowers, and face seals.
    In addition, the operator would be required to ensure that no 
occupation where PAPRs must be worn by the miners required to work in 
those particular job positions, the DO and other occupations in the 
affected MMU, are exposed to an equivalent concentration of respirable 
coal mine dust that exceeds the applicable dust standard.
    Finally, since the use of PAPRs as a supplementary control is not 
intended to be permanent and their use is being permitted until 
feasible engineering controls become available, proposed paragraph 
(b)(3) would require the operator to continue to seek and implement 
additional improvements when they become available. To ensure 
conformance with these requirements, MSHA will review the operator's 
approved plan parameters, including the operator's compliance history, 
every 6 months to determine if the operator is using all feasible 
engineering controls and if the plan parameters continue to be suitable 
to the current operating conditions. If MSHA determines that other 
acceptable controls have become available which would be suitable to 
the particular MMU, MSHA would notify the operator and the 
representative of miners of its findings.
    MSHA approval to use PAPRs as a supplementary control may be 
revoked if the operator failed to meet the requirements of proposed 
paragraphs (b)(1), (2) and (3) of this section. If the operator's plan 
provisions are revoked, the operator would be required to submit a 
revision to the plan parameters for the affected MMU that would include 
a VPL at which compliance with the applicable dust standard would be 
achieved.
Section 70.212 Powered Air-Purifying Respirators (PAPRs); Conditions 
for Use under Special Circumstances
    Section 70.212 sets forth the special circumstances under which an 
operator would be permitted to use, on an intermittent basis, PAPRs to 
protect individual miners from excessive dust concentrations and for 
compliance purposes. Such use is only permitted after the plan 
parameters have been verified without the use of supplementary controls 
and additional remedial actions will not be practical or feasible 
because of the intermittent nature and duration of a special condition.
    Because of the dynamic nature of mining, it is not uncommon for a 
MMU to occasionally encounter operating conditions which directly 
impact the ability of the previously verified plan parameters to 
effectively control respirable dust. This is especially true when the 
particular condition encountered varies from the operating conditions 
under which the adequacy of the plan parameters was originally 
demonstrated. It is not because an operator may have failed to 
adequately take such conditions into account when designing the plan 
parameters, but because the proposed verification process requires the 
adequacy of the plan parameters to be demonstrated only under typical 
operating conditions. For example, encountering a significant rock band 
in the coal seam containing a high percentage of quartz would be 
considered a unusual circumstance since its occurrence is not routine. 
While this may have occurred in the past and may occur again, the 
operator cannot predict with certainty when this condition might 
reoccur. Because of the unpredictable nature of such an occurrence, it 
may not be practical to factor this into the design of the plan 
parameters.
    While the Mine Act and implementing regulations intend for the 
working environment to be free of excessive dust at all times, MSHA 
recognizes that it may not be practical or feasible to implement 
additional engineering controls whenever these unusual conditions 
occur, especially when they occur intermittently for a brief period of 
time. Even if the operator makes a concerted effort to implement 
additional engineering controls, it may require an extended period of 
time to complete and verify the effectiveness of the adjustments, 
during which time some miners may not be adequately protected from 
excessive dust.
    Before MSHA will grant authorization to use PAPRs for compliance 
purposes, the operator must show that the particular condition or 
situation is atypical, occurs only occasionally, and is beyond the 
control of the operator. Increased production levels which exceed the 
VPL and any other situations which are more routine and therefore under 
the operator's control would not be characterized as unusual 
conditions. However, because of the difficulty in maintaining proper 
ventilation along a longwall face, during start-up, MSHA will consider 
and encourage the use of PAPRs at longwall MMUs until the first gob 
fall. The types of evidence MSHA would consider when the unusual 
condition encountered involves cutting rock occasionally, would include 
information on quartz levels, the duration and frequency of reduced 
standards, and/or on the reject rate for a particular MMU.
    MSHA anticipates questions regarding what constitutes special 
circumstances under this proposed section. It is not possible or 
appropriate to set forth all circumstances which might be covered by 
this proposed rule. Each request will be considered by the district 
manager on a case-by-case basis. The district manager will rely on past 
in-mine experience and the information provided by the operator in 
determining whether the special circumstances under which the applicant 
is seeking authority to use PAPRs, occurs intermittently and is the 
best way to protect the affected miners during such periods. The Agency 
specifically solicits comments on these issues, especially, with regard 
to what other special circumstances in mining may necessitate the 
immediate use of PAPRs.
    Under proposed paragraph (a), an operator can file a written 
request seeking MSHA approval to use PAPRs under special circumstances: 
(1) When submitting a ventilation plan under Sec.  75.370 of this 
title, (2) when required to verify a previously approved ventilation 
plan that was revised in accordance with Sec.  75.370(f), or (3) after 
the district manager approves the plan parameters based on the results 
of operator verification samples. To the extent possible, the operator 
must submit a written request prior to encountering special 
circumstances to assure prompt review, and revision to the ventilation 
plan. A copy of the request must be provided to the representative of 
miners at the time of submittal and posted on the mine bulletin board 
to alert the miners working in the affected MMU. The district manager 
will consider all comments and, if requested, provide copies of these 
comments to the operator.

[[Page 10821]]

    In addition to showing that the particular circumstances 
necessitating use of PAPRs occur occasionally and are beyond the 
control of the operator, proposed paragraph (b) requires the operator 
to revise the previously approved plan provisions to incorporate the 
provisions proposed in Sec.  70.210(a)(1), (2) and (3).
    Once approval is granted by the district manager, proposed 
paragraph (c)(1) through (3) sets out the requirements for the use of 
PAPRs. The operator will be required to notify, in writing or by 
electronic means, the district manager and the representative of miners 
within 24 hours of determining that current operating conditions 
necessitate use of PAPRs. This would enable MSHA to follow-up with an 
in-mine visit to verify the operating conditions under which PAPRs are 
being used and whether the operator is in full compliance with the 
letter of approval and with the provisions of proposed Sec.  
70.211(b)(1) and (2). It is the responsibility of mine management to 
ensure that PAPRs are worn for all required periods and to see that the 
conditions stipulated in the plan, which are necessary to protect miner 
health, are followed.
    When PAPRs are used during MSHA compliance sampling, the 
determination of compliance with the applicable dust standard will be 
made in accordance with proposed Sec.  70.218(a). For occupations under 
a PAPR protection program, compliance would be assumed if the 
equivalent concentration measurement, as determined in accordance with 
Sec.  70.2 and as discussed under Sec.  70.211, is less than the 
citation threshold value (CTV) listed in Table 70-2 that corresponds to 
the applicable dust standard in effect.
    Unusual operating circumstances do not normally last for an 
extended period of time. Therefore, use of PAPRs for compliance 
purposes is limited to 30 consecutive days. The district manager may 
revoke the operator's authority to use PAPRs under special 
circumstances for failure to comply with this requirement. If the 
operator exceeds this time period or if respirable dust samples taken 
by either the operator or MSHA indicate miners are being overexposed, 
the operator must revise and verify the adequacy of the proposed plan 
parameters under the prevailing operating conditions. Comments are 
specifically requested on this issue.
    Permitting the use of PAPRs to supplement existing engineering 
controls to protect individual miners under special circumstances as 
proposed is consistent with the intent of the Mine Act and is in the 
best interest for miner health.

Section 70.213 through 70.214

Use of Administrative Controls

    These sections would establish the requirements for using 
administrative controls as a supplementary control to maintain the 
personal work environment of the affected miners at a safe exposure 
level when MSHA has determined that further reduction in respirable 
dust concentrations cannot be achieved using all feasible engineering 
or environmental controls.
Section 70.213 Administrative Controls; Requirements for Approval
    If the operator chooses to use administrative controls as a 
supplementary control measure, this proposed section would require the 
operator to submit a revision to the plan parameters to the district 
manager within five days of receipt of MSHA's written approval in 
accordance with proposed Sec.  70.209(b). The proposed revision would 
specify the engineering controls that are capable of maintaining the 
environment of any occupation under administrative controls and the DO 
or another occupation designated by the district manager at or below 
the verification limits.
    In addition to specifying all feasible engineering controls to be 
used, proposed paragraph (a)(2) would require the operator to include a 
detailed description of each specific administrative control to be 
implemented. Because the effectiveness of administrative controls is 
based on adherence to strict time periods, work schedules, and or other 
administrative controls, the revision must explain how the operator 
would verify compliance with the prescribed administrative control. The 
district manager may require the operator to modify the administrative 
controls before granting provisional approval of the proposed plan 
revision incorporating the use of such measures as a supplementary 
control.
    Proposed paragraph (b) would require the operator to verify, in 
accordance with proposed Sec.  70.206(b) through (e), the adequacy of 
the revised plan parameters incorporating the use of administrative 
controls within 30 calendar days of obtaining provisional approval from 
the district manager. Accordingly, respirable dust samples would be 
collected in the environment of (1) The occupation(s) under 
administrative controls, (2) the DO, and (3) other occupation(s) that 
may be designated by the district manager.
Section 70.214 Administrative Controls; Approval and Conditions for 
Continued Use; Revocation of Approval
    This proposed section establishes the criteria that the district 
manager would use to determine whether to approve the operator's 
proposed revision to the plan parameters incorporating the use of 
administrative controls as a supplementary control. As previously 
discussed under proposed Sec.  70.207, approval of the proposed 
revisions would depend on the results of verification sampling and the 
operating conditions in effect during the time each sample is 
collected. The district manager would approve the revisions if (1) no 
valid equivalent concentration measurement exceeds the critical values 
listed in Table 70-1 that correspond to the number of shifts sampled, 
and (2) the revision incorporates the dust control parameters and 
administrative controls that were in effect during verification 
sampling. For the district manager to approve the revised plan 
parameters for a MMU based on only one shift of sampling, no valid 
concentration measurement can exceed 1.71 mg/m3 for 
respirable coal mine dust or 87 [mu]g/m3 for respirable 
quartz.
    Proposed paragraph (b) establishes the requirements for the 
continued use of administrative controls as a supplementary control. To 
continue to use administrative controls and operate under the same 
conditions that were in effect during verification sampling, the 
operator would be required to comply with the approved revised plan on 
each production shift, and particularly with the prescribed 
administrative controls. Since miners must actively comply for 
administrative controls to be effective in reducing dust exposure, the 
operator must train the affected miners to follow prescribed 
administrative controls and require their cooperation for them to be 
effective.
    In addition, the operator would be required to ensure that no 
occupation is exposed to concentrations of respirable dust that exceed 
the applicable dust standard. MSHA will evaluate the effectiveness of 
the dust control parameters and the operator's performance in complying 
with all provisions of the approved plan.
    Since the use of administrative controls as a supplementary control 
is not intended to be permanent and their use could be permitted only 
until feasible engineering controls become available, proposed 
paragraph (b)(3) would require the operator to continue to seek and 
implement additional improvements when they become available. To ensure 
compliance with

[[Page 10822]]

these requirements, MSHA will review the operator's approved plan 
parameters, including the operator's compliance history, every 6 months 
to determine if the operator is using all feasible engineering controls 
and if the plan parameters continue to be suitable to the current 
operating conditions. If the district manager determines that other 
controls have become available which would be suitable to the 
particular MMU, the district manager would notify the operator and the 
representative of miners of such findings.
    MSHA approval to use administrative controls as a supplementary 
control may be revoked if the operator fails to meet the requirements 
of proposed paragraphs (b)(1), (2) and (3) of this section. If the 
operator's plan provisions are revoked, the operator would be required 
to submit a revision to the plan parameters for the affected MMU that 
would include a VPL at which compliance with the applicable dust 
standard would be achieved.
Section 70.215 Quarterly Evaluation of Approved Plan Parameters
    Because conditions in an underground mine are constantly changing, 
the effectiveness of previously approved dust control parameters for a 
particular MMU may change. Consequently, plan parameters may later be 
inadequate in preventing overexposures on individual shifts and 
adjustments may be necessary to continually comply with the applicable 
dust standard. Therefore, in addition to ensuring compliance with the 
plan parameters under existing Sec.  75.362(a)(2), the operator also 
has the responsibility to ensure that the plan parameters continue to 
be effective in controlling respirable dust as required by Sec.  
75.370(a), and to upgrade the plan parameters when deemed appropriate. 
This is necessary to prevent overexposures on individual shifts and, in 
the long run, the occurrence of coal workers' pneumoconiosis and 
silicosis in miners.
    The importance of assessing the continued adequacy of plan 
parameters and the role of operators in that process was recognized by 
the Dust Advisory Committee:

    MSHA should develop specific performance requirements for 
operator sampling relative to documentation of continued adequacy of 
the plan parameters. (MSHA, 1996)

To accomplish this, proposed Sec.  70.215, would require an operator to 
implement a 3-month interval (quarterly) sampling program at MMUs where 
the continued adequacy of the approved plan parameters is in question 
and miners are at risk of being overexposed as indicated by MSHA-
collected respirable dust samples used to audit operator compliance 
with applicable standards. Therefore, rather than require all operators 
to sample quarterly, the quarterly monitoring requirement is triggered 
when airborne dust concentrations, as measured under MSHA's sampling 
program, exceed the applicable dust standard. This risk-based approach 
is more performance-oriented and minimizes unnecessary sampling. The 
purpose of operator quarterly sampling would be to monitor the adequacy 
and suitability of the approved dust control parameters under 
prevailing conditions.
    Since operators have the responsibility for providing a workplace 
that is free of excessive dust, all operators are encouraged to design 
and implement a monitoring program suitable to their specific mine to 
ensure that the applicable dust standard is not exceeded. MSHA believes 
that operators have a number of incentives to monitor the quality of 
the air in each MMU on a regular basis to ensure they can (1) assess 
the effectiveness of their dust control parameters or need for 
adjustments to continually comply with the applicable dust standard and 
(2) avoid citations and penalties during MSHA sampling inspections.
    Under the proposed rule, the sampling process would begin with the 
determination by the district manager of the particular MMUs which 
would be regularly sampled at the mine. In determining which MMUs at a 
mine should be sampled periodically, the district manager would, under 
the proposed rule, first review the results of respirable dust samples 
after each sampling inspection of a MMU. If a valid equivalent 
concentration measurement for any occupation exceeds the applicable 
dust standard by at least 0.1 mg/m3, quarterly sampling 
would be required.
    The proposal also provides for the suspension of quarterly sampling 
when all respirable dust samples submitted by the operator in 
accordance with this section, together with samples taken by MSHA 
during at least four consecutive quarters, demonstrated continuing 
compliance with the applicable dust standard. To ensure that the proper 
MMUs are exempted from quarterly sampling when miners are no longer at 
risk of being overexposed, each operator- and MSHA-collected sample 
must be at or below the applicable dust standard.
    Under paragraph (a), the operator would begin quarterly sampling 
during the next full 3-month period following MSHA notification of the 
designation of a MMU for sampling. The proposed rule provides a 
schedule for quarterly sampling. For example, during the period January 
1 through March 31, operators would be required to sample each 
designated MMU in producing status. When there is a change in the 
operational status of the particular MMU that affects operator 
monitoring, proposed Sec.  70.219(a) requires the operator to report 
such status change to the district manager. Suppose, for example, a MMU 
has been in nonproducing status for 75 calendar days during the current 
quarterly sampling period, the operator would still be expected to 
satisfy the sampling requirements because there would be sufficient 
time remaining in the current period to sample the required one shift. 
Failure to submit the required number of valid respirable dust samples 
within a given quarterly period would constitute a violation of this 
provision. Operators would be encouraged to conduct the required 
sampling at the beginning of each quarterly sampling period. All 
samples submitted by the operator would be processed by MSHA.
    To provide consistency and uniformity among operator-collected 
samples for purposes of monitoring plan effectiveness, the proposed 
monitoring program would require the operator to sample selected 
occupations in accordance with proposed Sec.  70.206(b), (d) and (e) 
for one shift. Also, since the objective of quarterly sampling is to 
evaluate the continued adequacy of the approved plan parameters under 
the prevailing conditions, each sample must be collected under the 
operating conditions specified in proposed Sec.  70.201(e) which 
specifies that the amount of material produced must equal or exceed the 
VPL, unless sampling in accordance with proposed Sec.  70.220(d). Only 
the dust control parameters listed in the approved ventilation plan, at 
levels not exceeding 115 percent of the specified quantities, are to be 
in place during sampling. As in verification sampling, if the operator 
fails to attain the VPL on the shift sampled, all samples for that 
shift will be voided by MSHA. However, if any sample, regardless of 
production, is found to exceed the applicable dust standard by any 
amount, it would be used by MSHA to determine the equivalent 
concentration for that occupation. Also, if the MMU being sampled is 
authorized to use PAPRs under special circumstances (proposed

[[Page 10823]]

Sec.  70.212) and those circumstances prevent the MMU from achieving 
the VPL, all samples for that shift would be used to determine the 
equivalent concentration for the affected occupations.
    Since these samples are for evaluation purposes, the operator would 
not be required to use a control filter in accordance with proposed 
Sec.  70.201(d). The district manager may require the operator to 
reverify the adequacy of the plan parameters for a particular MMU based 
on these results and other compliance data if the data indicates that 
the parameters are no longer effective in maintaining compliance. If, 
on the other hand, the operator or MSHA is prevented from confirming 
the suitability of the approved dust control parameters to the current 
operating conditions because of repeated submission of invalid samples, 
reverification of the plan parameters would be required by the district 
manager.
    Under proposed paragraph (c), when a valid equivalent concentration 
measurement exceeds the applicable dust standard by at least 0.1 mg/
m3, the operator must make approved respirators available to 
the affected miners in accordance with Sec.  70.300, unless the 
occupations are under a PAPR protection program. The operator must 
determine the cause and correct the identified deficiency to reduce the 
concentration of respirable dust to within the applicable dust standard 
and avoid future overexposures. This requires the operator to review 
the dust control parameters and to determine what factors may have 
contributed to the overexposures. As discussed elsewhere in the 
preamble, if the sampled occupation is under an approved PAPR program, 
each valid concentration measurement would be adjusted in accordance 
with Sec.  70.2. The equivalent concentration would be compared to the 
applicable dust standard. For example, assume the reported equivalent 
concentration of a sample is 2.56 mg/m3 and the MMU is 
assigned a protection factor of 4. Then the equivalent concentration 
measurement, adjusted for the use of a PAPR, is 0.64 mg/m3 
[2.56 mg/m3/4 = 0.64 mg/m3].
    Additionally, since the presence of excessive dust poses a 
significant health hazard to miners, proposed paragraph (c)(3) would 
require excessive dust conditions to be recorded in the same manner, 
but with some exceptions, as the hazards recorded under Sec.  75.363(b) 
of this title. The record would include: (1) The date the sample was 
taken; (2) the location in mine and the occupation where the excessive 
dust condition occurred; (3) the equivalent concentration measurement 
of each sample collected; (4) the specific action taken to reduce the 
concentration of respirable dust to within the applicable dust 
standard. MSHA will be providing the operator with a respirable dust 
sample data report that contains much of the same information required 
under this paragraph. In order to reduce the operator's paperwork 
burden, the MSHA respirable dust sample data report could serve as this 
record, provided the operator includes the specific corrective action 
taken, certifies its accuracy and completeness, and retains the record 
for at least 12 months at a surface location as required by Sec.  
75.363(c) and (d). The dust record does not need to be countersigned, 
provided that the mine official certifying the record is aware of the 
monitoring results and directed or supervised the implementation of the 
corrective actions. These records provide notice to mine management 
that excessive dust conditions are recurring, the locations in the 
mine, and the effectiveness of the various corrective actions. For 
example, if an excessive dust condition occurs repeatedly and the same 
corrective action is taken, the corrective action may not be effective. 
Posting the record on the mine bulletin board will alert all affected 
miners of the particular dust hazards to which they have been exposed 
and the specific corrective action(s) being taken by the operator to 
reduce the dust concentration in the work environment to within the 
applicable dust standard to prevent similar occurrences in the future. 
The requirement to inform miners is necessary to assure miners that the 
operator is making efforts to provide a safe and healthful work 
environment. This is a new requirement and the Agency solicits comments 
on the proposed approach to require that excessive dust conditions and 
the corrective action taken be recorded, certified and retained as 
currently required for other hazards under Sec.  75.363.
    If the results of quarterly sampling indicate that the approved 
plan parameters are no longer adequate to control respirable dust under 
the prevailing operating conditions, the operator must revise the plan 
parameters and submit the proposed revision to the district manager for 
review and approval. For example, if any valid equivalent concentration 
measurement meets or exceeds the citation threshold value (CTV) listed 
in Table 70-2 that corresponds to the applicable dust standard in 
effect, the plan parameters would need to be upgraded and verified 
under current conditions. Because the results indicate that miners are 
being overexposed, MSHA will conduct follow-up sampling whenever an 
operator's quarterly sample meets or exceeds the CTV and the plan 
parameters are not revised by the operator.
    Under proposed paragraph (e), the results of operator quarterly 
sampling will not be used to determine compliance with the applicable 
dust standard. If any sample result exceeds the CTV, the operator would 
not be cited for a violation as would be the case if MSHA sampled. The 
operator would, however, be required to take corrective action. Failure 
to take such action to reduce the respirable dust concentration within 
the applicable dust standard would be citable under this section.
    MSHA requests comments on the appropriateness of the criteria used 
to trigger operator monitoring of plan effectiveness and proposed 
frequency, especially with regard to the 3-month interval, that 
maximize the protection of miners' health. Also, whether a more 
performance-oriented requirement should be imposed on operators, 
requiring them to monitor at the frequency needed to assure, with 
reasonable accuracy, the continued adequacy of the approved plan 
parameters in preventing overexposures on individual shifts.
Section 70.216 Respirable Dust Samples; Transmission by Operator
    MSHA is proposing no substantive changes to existing Sec.  70.210, 
except for removing reference to Sec.  70.202 (Certified person; 
sampling) from existing paragraph (c) to eliminate repetition since 
revised Sec.  70.201 specifies that all sampling required under this 
part must be conducted by a certified person, and redesignating it as 
Sec.  70.216. Existing paragraph Sec.  70.210(e) would be removed since 
all samples submitted by the operator under this part would be 
processed by MSHA. The proposed rule, like the existing rule, requires 
all respirable dust samples collected in accordance with this part to 
be transmitted to MSHA within 24 hours after the end of the sampling 
shift in containers provided by the manufacturer of the filter 
cassette. The need to verify the adequacy of the dust control 
parameters for a particular MMU in the shortest possible time requires 
that samples be promptly transmitted to MSHA for analysis.
    Each sample transmitted by the operator must be accompanied by a

[[Page 10824]]

properly completed dust data card. All dust data cards submitted must 
be signed by a person certified to collect samples and must include 
that person's certification number. By signing the card, that person 
certifies that the sample was collected in accordance with the 
requirements of this part.
    To maintain program integrity, all samples collected by an operator 
would be considered by this proposed rule to fulfill the sampling 
requirements of this part. Samples to be used by operators for other 
purposes would have to be identified in writing or by electronic mail 
to the district manager, by each filter cassette identification number, 
prior to their intended use.
    Operators that use PCDMs under proposed Sec.  70.220 are exempt 
from the requirements of this section, except when transmitting samples 
for quartz analysis required by proposed Sec.  70.220(c).

Information To Be Posted on the Mine Bulletin Board

Section 70.217 Respirable Dust Samples; Report to Operator; and Posting
    Under the proposed rule, existing Sec.  70.210 would be revised and 
redesignated as Sec.  70.217. It specifies the type of sampling and 
other related information the operator would post on the mine bulletin 
board. The proposed posting requirements are intended to serve in the 
best interest of miners without being overly burdensome to operators. 
The continuation of posting requirements is intended to promote miner 
awareness of process of verifying the adequacy of the dust control 
parameters for each MMU specified in the mine ventilation plan and of 
the respirable dust conditions in the mine. This is consistent with the 
statutory intent that miners play a role in preventing unhealthy 
conditions and practices where they work. This approach is consistent 
with the recommendations of the Dust Advisory Committee regarding miner 
participation in the sampling process.
    Paragraph (a)(1) through (6) of the proposed rule retains the 
existing requirement regarding the types of data MSHA would report on 
samples submitted by the operator. The results of all MSHA sampling 
would be reported to the operator. The data report would include the 
identification of the MMU or DA in the mine where each sample was 
collected; the equivalent concentration of respirable dust for each 
valid sample; the occupation code, where applicable; and the reason for 
voiding any sample. In addition to providing data on individual 
samples, the Agency would also furnish information on the dust control 
parameters that were in effect during MSHA sampling by providing a copy 
of completed MSHA Form 2000-86 (Revised), Respirable Dust Sampling and 
Monitoring Data.
    Paragraph (b)(1) of the proposed rule retains the existing 
requirement that the operator post on the mine bulletin board the 
respirable dust sample data report provided by MSHA. The operator must 
post the end-of-shift exposure information if using a PCDM in 
accordance with Sec.  70.220. The results of all respirable dust 
samples collected by federal mine personnel that MSHA would provide 
under revised paragraph (a) must be posted. Additionally, the operator 
would post a copy of MSHA Form 2000-86 for each MMU sampled by federal 
mine personnel. This requirement would ensure that miners and their 
representative(s) are provided information concerning the quality of 
the mine air where they work and the dust control parameters under 
which MSHA sampling was conducted.
    MSHA recognizes the importance of input from the miners and their 
representatives in the plan approval process. To assure miners 
understand the verification process, proposed paragraph (b)(3) would 
require the posting of all written notifications received from the 
district manager pertaining to verifying the adequacy of the dust 
control parameters under this part. This includes all correspondence 
submitted in accordance with proposed Sec. Sec.  70.209 and 70.212. The 
district manager would be available to discuss with the representative 
of miners as well as individual miners all aspects of the plan 
parameter verification process.
    Proposed paragraph (c) specifies the length of time the information 
provided under paragraph (b) would be posted on the mine bulletin 
board. Results of operator verification sampling and all written 
notifications received from the district manager that pertain to the 
plan verification procedures could be removed immediately following 
notification of approval of the plan parameters for a particular MMU. 
Correspondence required under proposed Sec.  70.212(c)(1) regarding the 
occurrence of special circumstances requiring the use of PAPRs must 
remain posted for the period of time that PAPRs are in use. The 
respirable dust sample data report provided by MSHA on operator 
sampling in accordance with proposed Sec.  70.215 and MSHA sampling 
results, including the information specified in proposed paragraph 
(b)(2) of this section, must be posted for at least 31 calendar days 
following receipt. If using a PCDM, the end-of-shift exposure data 
along with the information specified in paragraph (b)(2) must be posted 
for at least 7 calendar days following the end of the sampling shift.
Section 70.218 Violation of Respirable Dust Standard; Issuance of 
Citation; Action Required by Operator; and Termination of Citation
    Proposed Sec.  70.218 addresses the circumstances under which MSHA 
would issue a citation for excessive dust and establishes the specific 
actions that an operator would be required to take within the time for 
abatement fixed in the notice. It also sets forth the conditions under 
which MSHA would terminate such citations.
    Under proposed paragraph (a), the operator would be cited for a 
violation of either Sec.  70.100(a) and (b), or Sec.  70.101 when a 
valid equivalent concentration measurement for any occupation sampled 
by MSHA exceeds the citation threshold value (CTV) listed in Table 70-2 
that corresponds to the applicable dust standard in effect. As 
discussed in section III.A.4. of the preamble, these measurements will 
be based on single-shift samples collected with approved sampling 
devices that will be operated portal-to-portal. The devices will remain 
operational, during the entire shift or for 8 hours, whichever time is 
less, as has been the long-standing practice.
    The CTVs and an explanation of how they were derived was originally 
published in Federal Register notice of February 3, 1998 (63 FR 5687), 
entitled ``Coal Mine Respirable Dust Standard Noncompliance 
Determinations.'' As explained in that notice and in Appendix C of the 
current notice of proposed rulemaking, each CTV was calculated so that 
citations would be issued only when a single-shift measurement 
demonstrates noncompliance at least at a 95 percent confidence level. 
Under this proposed rule, MSHA would issue no more than one citation 
based on the result of single shift samples from the same MMU, unless 
separate citations are warranted for occupations exposed to different 
dust-generating sources. The following examples illustrate how MSHA 
would apply the CTVs to make noncompliance determinations. Suppose that 
a measurement of 2.41 mg/m3 is obtained for the DO, and 
measurements of 2.34, 1.54, 2.00, and 1.56 mg/m3, are 
obtained for four other occupations exposed to the same dust-generating 
source as the DO during a single shift on a MMU required to comply with 
an applicable dust standard of 2.0 mg/m3. Because at

[[Page 10825]]

least one measurement exceeds the 2.33-mg/m3, CTV (the 
citation value for a 2.0-mg/m3 standard), a citation would 
be issued for exceeding the applicable dust standard on the shift 
sampled. Even though two individual measurements (2.41 and 2.34 mg/
m3) exceeded the CTV, one of which is the DO, only one 
citation would be issued. The DO would be identified in the narrative 
of the citation as the affected working environment, because all 
occupations were exposed to the same dust-generating source. Since MSHA 
would assume responsibility for all compliance sampling under this 
proposed rule, these five occupations would be resampled by federal 
mine personnel during abatement sampling to verify that the condition 
causing the excessive dust levels has been corrected if the district 
manager concluded that a revised plan was not necessary.
    Suppose that in the previous example the 2.34-mg/m3 
measurement was obtained for a roof bolter, and the MMU was being 
ventilated using a double-split ventilation system. This means that the 
roof bolter, working on a separate split of air from that of the 
continuous miner, is exposed to a different dust generating source than 
the DO. Therefore, the roof bolter may not be adequately protected by 
dust controls implemented for the DO. Consequently, two citations would 
be issued. Since MSHA samples would be used, all dust control 
parameters and mining activity would be documented on MSHA Form 2000-
86. This information would be reviewed by MSHA along with the sample 
results to determine if the dust control parameters specified in the 
approved ventilation plan would need to be upgraded.
    MSHA believes that, because of the large ``margin of error'' 
separating each CTV from the corresponding applicable dust standard, 
use of the CTV table would provide ample protection against erroneous 
citations, a concern raised by previous commenters. This matter was 
fully explored in the analysis published in Appendix C of the February 
3, 1998 notice (63 FR 5703-5709). That analysis showed that for 
exceptionally well-controlled environments, the probability that any 
given citation is erroneous will be substantially less than 5 percent. 
The analysis also showed that this probability is even smaller in 
environments that are not well controlled. Therefore, any citation 
issued under this proposed rule in accordance with the CTV table would 
be much more likely the result of excessive dust concentration rather 
than measurement error. With regard to the risk of erroneous failures 
to cite, MSHA concluded that ``the probability of erroneously failing 
to cite a case of noncompliance at a given sampling location is less 
than 50 percent when the applicable dust standard is exceeded on a 
significant proportion of shifts at that location'' (63 FR 5709).
    Furthermore, noncompliance determinations based on the results of 
single-shift samples would reduce the chances for failure to cite cases 
of noncompliance. According to the inspector sampling inspections of 
MMUs conducted between August and December 2001, only 14 MMUs were 
found to be in violation of the applicable dust standard. These MMUs 
were cited under the more recent enforcement policy of averaging 
measurements taken over multiple shifts, compared to 260 MMUs that 
would have been citable using single-shift measurements in combination 
with the CTV table. This clearly demonstrates that the proposed 
enforcement strategy would not compromise miners' health, instead it 
would have identified 246 additional instances of overexposure. 
Otherwise, these overexposures would continue to go undetected under 
the current policy of measurement averaging.
    MSHA has also carefully considered suggestions from previous 
commenters that the Agency cite for noncompliance whenever any single-
shift measurement exceeded the applicable dust standard as this would 
provide greater health protection to the miner. However, MSHA rejected 
these suggestions because an enforcement action might not be sustained 
at this level of confidence. The likelihood that a particular 
measurement exceeds the applicable dust standard, but not the CTV, due 
to measurement error, can actually exceed the likelihood that the 
measurement exceeds the standard due to excessive dust concentration. A 
thorough technical discussion of this issue is provided at 63 FR 5709-
5712 (Appendix D of the Federal Register notice cited above).
    MSHA has concluded that using single-shift measurements for 
noncompliance determinations in accordance with the CTV table neither 
increases nor decreases the applicable dust standard. Operators would 
continue to be required to maintain compliance with the applicable dust 
standard at all times. Also, the operator's dust control parameters 
must be verified as adequate to maintain dust concentrations at or 
below the applicable dust standard on all shifts, not merely at or 
below the CTV.
    As explained in the notice regarding single-shift measurements of 
respirable coal mine dust published in today's Federal Register, the 
Mine Act requires MSHA to regulate exposures on each shift. Since MSHA 
does not track the number of shifts each miner works over a lifetime, 
MSHA must, protect miners by limiting their exposure on each shift. 
Furthermore, as explained in Parts VI and VII of today's notice, 
eliminating overexposures on individual shifts is beneficial to miners' 
health. For miners working where there is a pattern of recurrent 
overexposures on individual shifts, eliminating such overexposures is 
expected over a working lifetime, to significantly reduce the risk of 
CWP. Therefore, the Secretary has concluded that equivalent dust 
concentrations should be maintained below the applicable dust standard 
on each and every shift.
    If an operator receives a citation for exceeding the applicable 
dust standard, proposed paragraphs (b)(1) through (4) would require the 
operator to take specific actions to immediately protect miners and to 
prevent them from being overexposed on subsequent shifts within the 
time period fixed in the citation. First, the operator would continue 
to make available approved respiratory equipment to affected miners in 
accordance with existing Sec.  70.300 and encourage their use until the 
overexposure condition is corrected, unless the cited occupation is 
already under a PAPR protection program. The operator would then review 
the dust control parameters in effect to determine the cause of the 
excessive dust concentration and correct any deficiencies identified to 
reduce the equivalent concentration to within the applicable dust 
standard. If the corrective action the operator takes indicates that 
the dust control parameters originally approved for the MMU may no 
longer be adequate for the current conditions, the operator should 
revise the plan parameters.
    Since MSHA would be assuming responsibility for all compliance 
sampling, proposed paragraph (a)(4) would require the operator to 
notify the district manager in writing or by electronic means, of what 
those corrective measures are within 24 hours after implementation. 
This would enable the district manager to determine whether MSHA should 
schedule sampling to assess the adequacy of the operator's corrective 
actions or whether to require the operator to initiate verification 
sampling. This determination would be based on (1) the review of the 
information the operator provides; (2) the latest MSHA inspection 
report documenting the measured quantities of the dust control

[[Page 10826]]

parameters that were in use and other conditions that were in effect at 
the time of sampling that resulted in MSHA issuing a citation for 
excessive dust; and (3) the operator's prior performance in complying 
with the plan parameters.
    If the district manager concludes that the corrective measures 
taken are sufficient to achieve and maintain compliance, MSHA would 
conduct sampling to determine if the operator's actions were effective 
to gain compliance. For example, if the operator believes that the 
overexposure was caused by improperly following work practices, the 
proper course of action would be to review these work practices with 
the affected miners rather than require the operator to revise the 
plan. Since there would be no need to change the plan parameters, MSHA 
would initiate abatement sampling in this particular case. Like 
compliance sampling, federal mine personnel would sample five different 
occupations including the occupation originally cited for the entire 
shift or for 8 hours, whichever time is less. However, if this problem 
should recur, the district manager would inform the operator that the 
plan parameters are no longer adequate to provide the required level of 
health protection and require the operator to initiate verification 
sampling.
    If, on the other hand, the district manager determines that dust 
control parameters may not maintain respirable dust levels at or below 
the applicable dust standard and requires the operator to upgrade the 
dust control portion of the mine ventilation plan, the operator would 
be required to initiate the plan verification process under proposed 
Sec.  70.206.
    Under proposed paragraph (c), an excessive dust citation would be 
terminated when the results of all valid respirable dust samples 
collected by MSHA were at or below the applicable dust standard. The 
subsequent action form would clearly and fully describe the action 
taken to abate the violation. If compliance was demonstrated, the 
operator may be required to revise the plan parameters depending on the 
type of corrective action taken to abate the violation. This would 
include, at a minimum, the actual dust control parameters that were in 
effect when MSHA sampled the MMU. If MSHA samples indicate continued 
noncompliance, then MSHA may proceed to revoke approval of the dust 
control provisions of the ventilation plan. The operator may be 
required to initiate the verification sampling if the district manager 
determines that the dust control parameters originally approved are no 
longer adequate to maintain respirable dust levels at or below the 
applicable dust standard under current operating conditions at the MMU.
    If, instead of MSHA conducting sampling to determine whether the 
operator's actions were effective to gain compliance, the operator 
initiates verification sampling under proposed Sec.  70.206, MSHA would 
terminate a citation for excessive dust after the revised plan 
parameters were verified by the operator to be adequate for the current 
mining conditions.

Reporting of Changes in Operation Status

Section 70.219 Status Change Reports
    The proposed rule would retain the existing provision of Sec.  
70.220, which would be redesignated as Sec.  70.119, with some 
revision. Not only would the operator continue reporting to the 
district manager changes in the operational status of a mine, MMU, or 
DA that affect the respirable dust sampling requirements of this part, 
but also when such status changes could potentially affect compliance 
sampling which will be conducted by MSHA. This would enable MSHA to 
carry out its sampling responsibilities more effectively and 
efficiently by avoiding unnecessary mine visits. Status changes would 
be reported either in writing or by electronic mail within three 
working days after the status change occurred.

Use of Personal Continuous Dust Monitors (PCDM) to Monitor Exposure

Section 70.220 Personal Continuous Dust Monitor (PCDM)
    MSHA has long recognized that continuous monitoring of the work 
environment offers the potential to improve miner health protection. 
The current system of monitoring concentrations of respirable dust to 
which miners are exposed relies on periodic sampling and on corrective 
actions taken after the delay in obtaining the sampling results. 
Continuous monitoring, on the other hand, would allow mine operators 
and miners to be aware of the actual dust conditions on a real-time 
basis. This would provide mine personnel with current information on 
the performance and condition of the dust control parameters. Early 
indications of deteriorating conditions, when the dust levels approach 
the applicable dust standard, would enable mine personnel to take 
appropriate corrective measures, thus averting possible overexposure. 
The health benefits of continuous monitoring were also recognized by 
the Task Group and the Dust Advisory Committee both of which 
recommended accelerated development, field testing, and immediate 
deployment of such monitors once verified as reliable.
    While such a monitor is not yet commercially available, significant 
progress has been made to advance the state of personal continuous 
monitoring technology, especially since MSHA published its proposed 
rule on plan verification on July 7, 2000. According to NIOSH, a one-
piece personal dust monitor (called ``PDM-1'' for short) would be 
available for in-mine use by the end of 2003. This device is designed 
to provide continuously-measured exposure information in real-time 
during the shift, projected end-of-shift average concentration, and the 
time-weighted average dust concentration reading within 15 minutes 
after the end-of-shift.
    Therefore, as recommended by the Dust Advisory Committee and urged 
by the mining community, MSHA is proposing a new standard under Sec.  
70.220 to encourage deployment of the PDM-1 or other approved PCDMs by 
permitting operators to use this technology in conjunction with 
engineering and administrative controls as part of a comprehensive dust 
control program to prevent overexposures on individual shifts.
    Proposed paragraph (b) would permit the operator to use 
administrative controls without obtaining approval from the 
Administrator for Coal Mine Safety and Health under proposed Sec.  
70.209. The operator would be required to include in the proposed plan, 
the specific administrative controls to be used, how each would be 
employed and by whom, and the method for ensuring that such controls 
are complied with on each shift. In addition, the operator would be 
required to identify the miners or specific occupations to be monitored 
on each shift using PCDMs and to implement procedures to ensure that no 
miner will be exposed during any shift to dust concentrations in excess 
of the applicable dust standard.
    Since the device is designed to display continuous real-time dust 
concentrations, the operator would be expected to develop written 
procedures for the proper use of this type of dust monitor. Key to the 
successful employment of this technology is the proper application of 
its capability to supply timely information on dust levels and miner 
exposure during the shift. The ability to be aware of the dust levels 
to which miners are exposed in real time would require the operator to 
develop specific guidelines regarding

[[Page 10827]]

the frequency with which the exposure measurements will be read and the 
types of action to be taken and by whom. The operator would need to 
specify how and by whom will the end-of-shift measurements be recorded 
and certified. The operator should also detail the role of the miner in 
this process. To ensure the continued reliability of the information 
supplied by the instrument, the operator must follow the calibration 
and maintenance procedures prescribed by the manufacturer. MSHA 
technical assistance would be available to assist any operator who 
elects to use this technology in developing an effective and reliable 
exposure monitoring program.
    Proposed paragraph (c) would require the operator to demonstrate, 
as prescribed by proposed Sec.  70.204, the adequacy of the proposed 
plan in controlling respirable dust by monitoring each miner's exposure 
under the operating conditions specified in proposed Sec.  70.201(e). 
Since the objective is to verify the effectiveness of the operator's 
respirable dust control program, the PCDM would remain with a miner 
portal-to-portal and be operational for the entire shift or for 12 
hours, whichever time is less to reflect maximum length of an extended 
shift.
    Since the device is not designed to assess the quartz exposure of 
individual miners, the operator would be required to collect separate 
samples for quartz analysis. Samples would be collected in the same way 
as for individual miners assigned to the occupations identified in 
proposed Sec.  70.206(a). Additionally, in accordance with proposed 
Sec.  70.201(d), the operator would be required to use a control filter 
when collecting samples for quartz analysis. As discussed under 
proposed Sec.  70.201(d), the weight gain of each exposed filter 
cassette will be adjusted by subtracting the weight gain or loss of the 
control filter cassette. These samples would be transmitted to MSHA in 
accordance with proposed Sec.  70.216. Also, the end-of-shift exposure 
information for each miner along with production data must be posted on 
the mine bulletin board for 7 calendar days following completion of the 
shift.
    As previously discussed under proposed Sec.  70.207, approval of 
the operator's plan incorporating the use of PCDMs would depend on the 
results of verification sampling and the operating conditions in effect 
for each shift monitored. The district manager would approve the plan 
if (1) no valid equivalent concentration measurement exceeds the 
critical values listed in Table 70-1 that correspond to the number of 
shifts monitored, and (2) it incorporates the parameters that were in 
effect during verification sampling.
    When approval is granted by the district manager, the operator 
would be required to monitor the exposure of each miner on a MMU on 
every shift under the prevailing conditions, unless the operator 
demonstrated during verification sampling that the exposure of each 
miner working on the same shift is represented by sampling only the DO 
and/or another occupation specified in Sec.  70.206(a). If approved by 
the district manager, the operator would be permitted to conduct 
representative personal monitoring. Each PCDM would be operated portal-
to-portal and remain operational the entire shift or for 12 hours, 
whichever time is less.
    The end-of-shift exposure measurements would not be used by MSHA to 
cite an operator for exceeding the applicable dust standard. Instead, 
the operator would be required to take the actions required by proposed 
Sec.  70.215(c), (d) and (e) whenever a valid end-of-shift measurement 
exceeds the applicable dust standard by at least 0.10 mg/m3. 
Violations of either Sec.  70.100(a) or Sec.  70.101 would be cited 
when a valid sample taken by MSHA met or exceeded the citation 
threshold value (CTV) listed in Table 70-2 that corresponds to the 
applicable dust standard in effect. When cited, the operator would be 
required to take the actions required by Sec.  70.218(b). The district 
manager will consider the citation abated if the operator meets the 
requirements of proposed Sec.  70.218(c).
    Comments are solicited on the proposed monitoring approach and 
other alternative approaches using PCDMs to limit exposure of miners to 
respirable coal mine dust. Specifically, under what conditions should 
MSHA permit its use as part of the approved ventilation plan without 
requiring the adequacy of the operator's proposed exposure control 
program to be verified? If implementation of this technology is 
permitted as an alternative to plan verification, what specific 
provisions should be included in the ventilation plan to ensure that 
miners will not be overexposed on any particular shift? Should all 
miners be required to wear PCDMs or only specific occupations and, if 
so, which occupations? How frequently should PCDMs be used (e.g., every 
shift, etc.)? Should the end-of-shift measurements be used by MSHA to 
enforce compliance with the applicable dust standard? Is it appropriate 
to use PCDMs only in the face areas or in outby areas as well? Is there 
an alternative to a continuous monitoring program that could provide 
equivalent protection? Should there be an alternative approach tailored 
to small mines? If so, what should it consist of (e.g., monitor one 
shift each week)?
    Since the PCDMs is capable of supplying timely information on dust 
levels, how should engineering and administrative decisions be based on 
readings of the PDM? For example, should a PCDMs reading trigger an 
immediate check of the dust control parameters or adjustments to 
operating conditions, such as the amount of air being delivered to the 
working faces? Who should be responsible for deciding on the proper 
course of action to be taken based on a PCDMs reading (e.g., miner 
being monitored, section foreman, etc.)? Who should be empowered to 
make the determination to remove an individual so that their end-of-
shift exposure is not above the applicable dust standard?
B. Part 75
Section 75.370 Mine Ventilation Plan; Submission and Approval
    This proposed rule would amend Sec.  75.370 by adding a new 
paragraph (h) that reflects the proposed change in Sec.  70.2 and 
paragraph (d) of Sec.  70.201 of this part. Under proposed paragraph 
(h), the operator would be required to record and maintain records of 
the total amount of material produced each production shift by each MMU 
during the previous six-month period, which would be made available for 
inspection by authorized representatives of the Secretary and the 
miners' representative. This is the same type of production information 
that the operator is currently reporting on the dust data card 
accompanying each bimonthly sample and which is subsequently posted by 
MSHA on the Internet. Paragraph (h) would not require an operator to 
record and maintain other information such as recovery and reject rate, 
inherent moisture of the product, sulfur content or other variables 
associated with each production level.
    These production records are essential to demonstrate the adequacy 
of the dust control parameters in controlling respirable dust as 
required by Sec.  75.370(a)(1) of this title. The records are needed to 
establish the verification production level (VPL), in accordance with 
revised Sec.  70.2, under proposed Sec.  75.371(f), and to confirm that 
the 30-shift period on which the VPL is based represents typical 
production conditions for the MMU. Additionally, MSHA and the miners' 
representative need these records to monitor changes in production 
levels as it directly impacts the continued effectiveness of the plan's 
dust control

[[Page 10828]]

provisions. Finally, because verification and subsequent quarterly 
monitoring of the adequacy of plan parameters is conditioned on the 
VPL, these records are necessary to determine if the VPL used in 
approving the operator's dust control parameters for a particular MMU 
continues to reflect typical production levels at the MMU.
    The proposed rule would permit production records for each MMU to 
be maintained in any form utilized by the operator to measure the total 
amount of material produced, provided the method is the same as that 
used to establish the VPL under proposed Sec.  75.371(f). For example: 
number of loaded shuttle cars, feet of advance, raw tonnage, or number 
of longwall passes would each be an acceptable method of recording 
production--provided the same method was consistently used.
Section 75.371 Mine Ventilation Plan; Contents
    The proposed rule would revise paragraphs (f) and (t). Existing 
paragraph (f) would be revised to require the dust control provisions 
of the ventilation plan to include any specific work practices used to 
minimize the dust exposure of individual miners assigned to specific 
occupations, information on the location of the roof bolter(s) during 
the mining cycle for each continuous miner section, and the cut 
sequence for each longwall mining section. Also, the dust control 
provisions of every ventilation plan would be required to include the 
length of each normal production shift and the verification production 
level (VPL) as determined in accordance with revised Sec.  70.2. This 
information would enable MSHA to more effectively assess the 
suitability of the operators's proposed plan parameters before 
determining whether or not to grant provisional approval. For example, 
the dust control parameters may be less protective if verified over an 
8-hr shift when the length of the production shift is 9 hours. Also, 
since MSHA recognizes the critical role of miners in the implementation 
of the plan parameters at each MMU, this is intended to provide more 
information to miners concerning the specific conditions under which 
the adequacy of the plan parameters for each MMU was demonstrated. With 
this information, the miner will be able to bring problems to the 
attention of mine management or to request an inspection by MSHA under 
Sec.  103(g) of the Act if operating conditions no longer reflect those 
in effect during verification sampling and there is concern about the 
dust conditions at a particular MMU.
    Although a VPL and shift length for each MMU would be included in 
the ventilation plan, the operator would not be cited if the total 
amount of material produced or the length of the actual production 
shift is not as specified in the plan. MSHA considers these to be plan 
design criteria, not minimum plan parameters that must be in effect on 
every shift. MSHA would expect production on a MMU to exceed the VPL on 
about 33 percent of all production shifts. If the district manager 
determines that an operator's actual production exceeds the VPL on more 
than 33 percent of the production shifts over a six-month period, or 
the shift length no longer reflects the conditions under which the 
approved plan parameters were originally verified, and operator or MSHA 
samples exceed the applicable dust standard, the district manager may 
require that the adequacy of the plan parameters be verified under 
different operating conditions of production or shift length.
    Since MSHA is proposing to revoke existing Sec. Sec.  70.207 and 
70.208, which require bimonthly sampling by mine operators, existing 
paragraph (t) would be revised to remove the provision that mine 
operators identify in the ventilation plan the locations where samples 
for designated areas (DA) would be collected, including the specific 
location of each sampling requirement, and the reference to Sec.  
70.208. However, to ensure that the mine atmosphere where miners 
normally work or travel is continuously maintained in compliance, 
proposed paragraph (t) would continue to require mine operators to 
identify in the mine ventilation plan the location of each DA, defined 
in revised Sec.  70.2, and the particular dust control measures that 
would be used at the dust generating sources for these locations. These 
locations would continue to be sampled by MSHA personnel as discussed 
earlier (see Background Section) to monitor operator compliance with 
the applicable dust standard and to assess the adequacy of the 
operator's dust control measures at these locations.

C. Part 90

    To maintain consistency with the proposed revisions to part 70, 
subpart A of this proposed rule also contains new definitions of 
identical terms. Included are definitions of new terms such as 
``approved sampling device,'' ``citation threshold value,'' 
``equivalent concentration,'' ``MRE,'' and ``quartz.''
    Subpart B of the proposed rule would be revised by changing the 
procedures for determining the average quartz percentage used to 
calculate the applicable dust standard. These are identical to the 
procedures proposed under Sec.  70.101. The proposed rule also 
clarifies the application of specific transfer and pay-protection 
provisions under special circumstances that reflect long-standing MSHA 
policy in effect since the rule became effective on December 5, 1980.
    The proposed rule substantially revises the existing operator 
sampling requirements under Subpart C of part 90. Consistent with the 
proposed amendment to part 70, the proposed rule would revoke existing 
provisions concerning operator bimonthly and abatement sampling of part 
90 miners. Consequently, Sec. Sec.  90.201(d) and 90.208 would be 
removed. While MSHA would be assuming responsibility for all 
enforcement-based monitoring of part 90 miners in underground coal 
mines, operators would continue to play a vital role in assessing the 
quality of the mine atmosphere in positions to which new or transferred 
miners are assigned to work.
    As under existing Sec.  90.207, which has been revised and 
redesignated as Sec.  90.204, the operator employing part 90 miners 
would be required to collect five valid samples within a prescribed 
time period for purposes of verifying the suitability of a new or 
transferred part 90 miner's assigned work position. To ensure that the 
part 90 miner is not personally overexposed, the duration of sampling 
would no longer be limited to 480 minutes, but would be carried out 
over the miner's entire work shift, regardless of the number of hours 
worked.
    Another significant change is how the results of operator-submitted 
samples would be analyzed by MSHA and the type of action required based 
on those results. MSHA would abandon its long-standing practice of 
relying on averaged results to make compliance decisions. Because 
averaging can obscure specific instances of overexposures by diluting 
sample results taken over multiple shifts, each valid sample would be 
compared with the applicable dust standard. Therefore, to be confident 
that a part 90 miner is placed in an atmosphere which actually meets 
the applicable dust standard, all five valid samples must be at or 
below the standard. If the result of any sample exceeds the standard by 
at least 0.1 mg/m3, the operator would be required to take 
corrective action and take an additional five valid samples for the 
affected part 90 miner.
    Since the primary purpose for taking these samples is to assess the 
suitability of the part 90 miner's working environment, these samples 
would not

[[Page 10829]]

be used by MSHA to cite the operator for noncompliance with the 
applicable dust standard. As discussed below, only MSHA-collected 
samples would be used for that purpose. However, an operator would be 
cited for failure to take appropriate corrective action to place the 
affected part 90 miner in an atmosphere that meets the applicable dust 
standard within the specified time period.
    Since MSHA would assume responsibility for compliance and abatement 
sampling, the proposed rule sets forth new procedures for determining 
noncompliance with the applicable dust standard; the specific actions 
that an operator would be required to take within the time for 
abatement fixed in a citation; and the conditions under which MSHA 
would terminate a citation for a violation of the standard. Under the 
proposed rule, citations for violations of Sec. Sec.  90.100 or 90.101 
would be issued only when a valid single-shift sample demonstrates 
noncompliance with at least 95-percent confidence. MSHA would consider 
a violation for excessive dust to be abated and terminate the citation 
when the result of a valid single-shift sample is at or below the 
applicable dust standard.
    Although existing subpart D has been revised to reflect MSHA 
sampling of part 90 miners, the specific requirements are essentially 
the same. It now states that when approving an operator's dust control 
plan, the district manager would consider the results of MSHA sampling 
for compliance or abatement purposes. It also indicates that MSHA 
would, through compliance and abatement sampling, monitor the continued 
effectiveness of the operator's dust control measures. Finally, 
throughout Part 90, ``shall'' has been replaced by ``must.''
    For ease of review, MSHA is republishing the entire regulatory text 
of subparts A, B, C and D of Part 90 as it will appear in the Code of 
Federal Regulations.

Sections 90.1 through 90.3

Scope, Definitions, and Part 90 Option

Section 90.1 Scope
    This section would remain unchanged.
Section 90.2 Definitions
    The proposed rule includes definitions virtually identical to 
corresponding definitions in proposed Part 70 for terms such as 
``approved sampling device,'' ``citation threshold value,'' 
``equivalent concentration,'' and ``MRE.'' Accordingly, as in Part 70, 
some existing definitions of terms such as ``certified person,'' 
``concentration,'' ``mechanized mining unit,'' and ``respirable dust'' 
have been modified either to more clearly convey the intended meaning 
under the proposed rule, to reflect the conventional definition or to 
be consistent with the definition of identical terms in proposed Part 
70 of this title. Most of the other definitions remain unchanged under 
the proposed rule. No discussion is included below if a definition 
would not change under the proposed rule.
Approved Sampling Device
    ``Approved sampling device'' would mean a sampling device approved 
by the Secretary and the Secretary of Health and Human Services under 
part 74 (Coal Mine Dust Personal Sampler Units) of this title; or 
approved by the Secretary when it has been demonstrated that a 
respirable dust concentration measurement can be converted to a 
concentration measurement equivalent to that obtained with an approved 
sampling device. Under the proposed rule, respirable dust sampling for 
Part 90 miners would continue to be collected using sampling devices 
approved by NIOSH pursuant to existing 30 CFR part 74. Also, to 
accommodate the adoption of advanced sampling technology in the future 
such as continuous respirable dust monitors, the proposed rule would 
permit the Secretary to approve and use any technologically advanced 
sampling devices that should become available in the future but could 
not be approved under the regulatory requirements of 30 CFR part 74.
    Therefore, under the proposed rule, any newly developed sampling 
instrument would be considered an approved device pursuant to this 
definition when the Secretary demonstrates that the respirable dust 
concentration measured by the new instrument can be converted to a 
concentration measurement equivalent to that obtained by a device 
approved under 30 CFR part 74 of this title.
Certified Person
    The existing definition would be modified by removing references to 
existing Sec. Sec.  90.202 and 90.203. The provision requiring the use 
of a certified person to conduct sampling as required by this part is 
being transferred to revised Sec.  90.201. Existing Sec.  90.203 which 
requires approved sampling devices to be maintained and calibrated by a 
certified person would be retained and redesignated as Sec.  90.202.
Citation Threshold Value (CTV)
    ``Citation threshold value'' would mean the lowest acceptable 
equivalent dust concentration measurement demonstrating that the 
applicable dust standard has been exceeded at a high level of 
confidence and at which MSHA would cite an operator for a violation of 
Sec. Sec.  90.100 or 90.101 under proposed Sec.  90.207. Since MSHA 
would be assuming responsibility for compliance sampling under the 
proposed rule or sampling currently being carried out by operators 
under existing Sec.  90.208(a), a determination of noncompliance would 
be based solely on the results of single shift samples collected by 
MSHA in accordance with proposed Sec.  72.500 of this title. Appendix C 
explains how each critical value listed in proposed Table 70.2 was 
derived. Each CTV is calculated to ensure that citations will be issued 
only when a single-shift measurement demonstrates noncompliance with at 
least 95 percent confidence.
Concentration
    The existing definition would be modified by replacing the term 
``substance'' with ``respirable dust'' to more clearly convey the 
meaning under the proposed rule.
Equivalent Concentration
    ``Equivalent concentration'' would mean the concentration of 
respirable dust, as measured by an approved sampling device, converted 
to an 8-hour equivalent concentration as measured by a Mining Research 
Establishment (MRE) sampler. This conversion is accomplished in two 
steps. First, the concentration measurement is multiplied by a constant 
factor prescribed by the Secretary specifically for the approved 
sampling device. The result is then multiplied by t/480, where t is the 
sampling time in minutes if longer than eight hours, to make it 
equivalent in dosage to the concentration as measured by an MRE sampler 
on an 8-hour work shift. Since sampling will be conducted over the 
course of the Part 90 miner's entire work shift, which includes travel 
to and from the assigned work position, t will also be equal to the 
length of the entire work shift of the miner being sampled. If the 
length of the Part 90 miner's work shift is eight hours or less, then t 
must equal 480 minutes.
    The current U.S. coal mine applicable dust standard is based on 
epidemiologic studies of British coal miners. In these studies, miners 
routinely worked 8-hour shifts, and their respirable dust exposures 
were assessed based on 8-

[[Page 10830]]

hour measurements using a sampling device known as the MRE instrument. 
Work shifts in U.S. coal mines now frequently exceed eight hours. 
According to a recent survey of MSHA District Offices conducted in 
August of 2002, approximately 48 percent of underground mines work 9-
hour shifts or longer. Therefore, to provide the intended level of 
protection to miners working longer than eight hours, it is necessary 
to convert coal mine dust concentration measurements to equivalent 8-
hour values as measured by the MRE instrument.
    The first step in the conversion from ``concentration'' to 
``equivalent concentration'' is intended to make the measurement 
equivalent to the concentration measured by an MRE instrument. This 
instrument was designed to selectively collect airborne dust in a way 
that would approximate the deposition of inhaled particles in the lung. 
Because the MRE instrument was large and cumbersome, other, more 
portable samplers were developed for use in U.S. coal mines. Currently 
approved sampling devices use a 10-mm nylon cyclone to separate the 
respirable fraction of airborne dust, instead of the four horizontal 
plates used in the MRE sampler. Such differences in sampler design lead 
to systematic differences in the amount of dust collected. Since 1980, 
measurements made using the currently approved cyclone-based devices 
operating at a flow rate of 2.0 liters per minute (lpm) were multiplied 
by the constant factor of 1.38 prescribed by the Secretary for the 
approved sampling device used. Application of this factor compensates 
for the difference in dust collection characteristics and makes the 
measurements equivalent to what would be obtained using an MRE 
instrument.
    Similarly, the second step in the conversion from ``concentration'' 
to ``equivalent concentration'' is intended to compensate for 
differences between current conditions and conditions under which the 
existing applicable dust standard was developed. Specifically, it is 
designed to ensure that miners working shifts longer than eight hours 
will be afforded the same level of protection as miners working an 8-
hour shift. MSHA developed the existing standard from 8-hour shift 
exposure measurements. Therefore, MSHA will adjust the measured 
concentration to be equivalent, in its effect on cumulative exposure, 
to a concentration over an eight-hour exposure period. This is 
accomplished by multiplying the concentration measurement by t/480, 
where t is the sampling time (i.e., length of the work shift) in 
minutes.
    The formula for an equivalent concentration is:
    [GRAPHIC] [TIFF OMITTED] TP06MR03.004
    
where t = sampling time in minutes (which will be the Part 90 miner's 
entire work shift) and airflow rate = 0.002 m3/min). The 
product of t and the airflow rate is the total volume of air from which 
dust is accumulated on the filter.
    The following example is meant to illustrate the effect of the 
second step in the conversion, multiplication by t/480, which adjusts 
for the full length of the work shift. In this example, it is assumed 
that the first step in the conversion, multiplication by 1.38 for 
equivalency with an MRE sampler, has already been performed.
    Suppose a Part 90 miner sample is collected over a 9-hour work 
shift. Suppose that the amount of dust accumulated during the shift is 
0.77 mg. If the concentration were not adjusted to an 8-hour equivalent 
concentration, the MRE-equivalent concentration would be calculated as 
0.98 mg/m3. Under the definition of ``equivalent 
concentration,'' this quantity is then multiplied by 540/480, yielding 
an equivalent concentration measurement of 1.10 mg/m3.
    This adjustment does not change the daily limit on the accumulated 
dose of respirable coal mine dust as intended by the existing exposure 
limit for coal mine dust. Since the current limit was based on an 
assumption that exposure occurs over an 8-hour shift, it corresponds to 
a daily cumulative dose of respirable coal mine dust of 8 x 1.0 = 8 mg-
hr/m3 as measured by the MRE instrument. The proposed 
definition of equivalent concentration will maintain this same MRE-
equivalent 8 mg-hr/m3 daily limit, regardless of the length 
of the working shift being sampled.
    To continue the example, the exposure accumulated during the Part 
90 miner's entire work shift is the same, whether over eight hours at 
an average of 1.10 mg/m3 or over nine hours at an average of 
0.98 mg/m3. In either case, the MRE-equivalent exposure 
accumulated during the entire work shift is 8.8 mg-hr/m3, 
which exceeds the intended limit of 8 mg-hr/m3. Under the 
proposed definition of ``equivalent concentration'' provided here, this 
will be reflected by the fact that, when more than 8 mg-hr/
m3 (MRE-equivalent exposure) is accumulated over the course 
of the particular shift sampled, the equivalent concentration will 
exceed 1.0 mg/m3, regardless of the shift's length.
    MSHA originally proposed a different, but mathematically 
equivalent, method of adjusting concentrations to an 8-hour equivalent 
and solicited comments on the proposed method. The proposed method 
would have defined ``concentration'' to mean what is here defined as 
``equivalent concentration.'' Instead of making an explicit adjustment 
to the concentration, using the factor of t/480 as in the present 
definition, the earlier proposed rule would have substituted 480 for 
the actual sampling time in the definition of respirable dust 
concentration. The proposed definition of ``equivalent concentration'' 
is meant to both preserve the ordinary definition of ``concentration'' 
and to clarify the adjustment to an 8-hour equivalent.
    MSHA believes that the proposed adjustment to an ``8-hour 
equivalent concentration'' is necessary to protect Part 90 miners from 
excessive exposures who normally work nontraditional or extended 
shifts. For example, a Part 90 miner working for ten hours at an 
average concentration of 1.0 mg/m3 will inhale and retain 
more respirable coal mine dust as a result of that specific shift than 
a miner working for eight hours at the same average concentration. By 
comparing the adjusted concentration to the concentration limit 
originally intended for Part 90 miners working an 8-hour shift, the 
same cumulative exposure limit is applied on individual shifts for all 
Part 90 miners.
    It should be noted that the ACGIH approach of reducing the 
permissible concentration to compensate for the extension of a shift 
beyond eight hours is similar in its effect to the approach taken here 
of adjusting the equivalent concentration upwards and comparing it to a 
fixed limit. MSHA makes similar adjustments for extended work shifts in 
the enforcement of exposure limits in metal and nonmetal mines under 30 
CFR 56.5001 and 57.5001. Taking into account the reduced recovery time 
that results from an extended work shift

[[Page 10831]]

would have led to a numerically greater and more protective adjustment, 
but this would also have introduced additional complexities in the 
calculation of equivalent concentration measurements. The Secretary 
believes that the method chosen strikes a reasonable balance between no 
adjustment at all, and a far more complex adjustment that would attempt 
to model clearance, deposition, and retention mechanisms.
Mechanized Mining Unit (MMU)
    The existing definition would be modified by removing the reference 
to Sec.  70.207(e) (Bimonthly sampling; mechanized mining units), which 
will be deleted, and replaced with proposed Sec.  70.206(d); and 
transfers the requirements for identifying each MMU specified in 
existing Sec. Sec.  70.207(f)(1) and (f)(2), to revised Sec.  70.2.
MRE
    ``MRE'' would mean Mining Research Establishment of the National 
Coal Board, London, England. This is a new definition which has been 
included to be consistent with revised Sec.  70.2.
Quartz
    The existing definition would be modified by specifying the 
analytical method that MSHA has been using since 1983 to determine the 
quartz content of respirable dust samples. The reason for this 
modification is to standardize the analytical procedure, thereby 
enabling other certified laboratories to reproduce quartz 
determinations made by MSHA. Also, to accommodate the adoption of 
improved or other quartz analytical techniques in the future, the 
definition of ``quartz'' has been expanded in the proposed rule to 
provide MSHA the flexibility to use alternative analytical techniques 
once these techniques have been demonstrated to provide quartz 
measurements that are equivalent to those obtained under current 
analytical method.
Respirable Dust
    The existing definition has been modified by transferring the 
requirement regarding what constitutes an approved sampling device to 
the proposed new definition of the term ``approved sampling device'' 
above.
Transfer
    The existing definition has been modified by clarifying when a 
change in work assignment would not constitute a transfer under 
proposed Part 90. MSHA recognizes that there may be circumstances which 
are beyond the control of the operator, such as equipment malfunction, 
that may interrupt work being performed by a Part 90 miner in his or 
her regular work assignment, necessitating the assignment of the Part 
90 miner to another job temporarily. For example, if the Part 90 miner 
is regularly assigned as a shuttle car operator in a MMU and the 
continuous mining machine breaks down, that Part 90 miner could be 
temporarily assigned to work in a different position and location in 
the mine. Consistent with MSHA's longstanding policy, such a change in 
duties would not constitute a transfer under Part 90 if the assignment 
does not last more than one shift. If such an assignment lasts longer 
than one shift, the operator would be required to notify the district 
manager in writing. This notice would list the temporary duties and the 
reasons for the assignment. Also, to demonstrate compliance with the 
applicable dust standard, the operator would be required to collect 
five valid samples from the newly assigned work position under proposed 
Sec.  90.204(a)(2). The 1.0-mg/m3 standard remains in effect 
even if the operator is unable to collect the required number of 
samples because of the short duration of the temporary assignment.
Section 90.3 Part 90 Option; Notice of Eligibility; Exercise of Option
    This section remains the same, with the exception of paragraphs (d) 
and (e) which have been revised to reflect the new address for mailing 
of the Exercise of Option Form or written request to re-exercise the 
option to work in a low-dust area of the mine.

Sections 90.100 Through 90.104

Dust Standards, Rights of Part 90 Miners

Section 90.100 Respirable Dust Standard When Quartz Is Not Present
    MSHA is proposing no substantive changes in existing Sec.  90.100, 
except for revising the section heading to correspond with the heading 
of proposed Sec.  70.100, which is identical, and removing the 
reference to Sec.  90.206 (Approved sampling devices; equivalent 
concentrations) and replacing it with Sec.  90.2. The requirements 
contained in revised Sec.  90.2 are similar to the standard in existing 
Sec.  90.206. The proposed rule retains the applicable dust standard of 
1.0 mg/m3.
Section 90.101 Respirable Dust Standard When Quartz Is Present
    The proposed rule would revise the section heading to correspond 
with the heading of proposed Sec.  70.101, which is identical. MSHA 
would retain the existing formula (10 divided by the concentration of 
quartz, expressed as a percentage) for reducing the applicable dust 
standard below 1.0 mg/m3 in proportion to the percentage of 
quartz when the quartz content of respirable dust in the mine 
atmosphere exceeds 10 percent, instead of 5 percent as contained in 
existing Sec.  90.101. Since the maximum standard for a Part 90 miner 
is 1.0 mg/m3, the quartz content must exceed 10 percent to 
cause a reduction in the applicable dust standard.
    The Agency would change the procedures for determining the average 
quartz percentage used to calculate the applicable dust standard. Only 
the results of MSHA samples would be used to establish the applicable 
dust standard. The quartz results of the three most recent valid MSHA 
samples would be averaged and the resultant percentage used to set the 
new applicable dust standard. However, if the Part 90 miner is already 
assigned to an area of the mine under a reduced standard below 1.0 mg/m 
\3\ when these revised procedures become effective, a new applicable 
dust standard would be established by averaging the results of the 
first two MSHA samples taken after the effective date with the quartz 
percentage associated with the applicable dust standard in effect. If 
fewer than two MSHA samples are taken, the existing standard would 
continue to remain in effect.
    Application of the revised procedures will result in the setting of 
reduced standards in a timely manner that (1) more accurately represent 
the quartz percentage of respirable dust in the environment of the Part 
90 miner at the time of sampling; (2) reflect the dynamics of the 
mining process and the changing geologic conditions of the mine strata; 
and (3) continue to protect Part 90 miners over multiple shifts.
    Under the proposed rule, MSHA would also report the quartz 
percentage to the nearest tenth of a percent, instead of truncating the 
results to the nearest full percentage as has been the longstanding 
practice. While this change will have no impact on the setting of 
applicable dust standards below 1.0 mg/m3, it will be more 
protective for other miners because it permits the setting of reduced 
standards at such levels as 1.1 mg/m3, 1.4 mg/m3, 
1.6 mg/m3, 1.8 mg/m3, and 1.9 mg/m3. 
Setting these particular standards currently is not mathematically 
possible using the above formula due to the practice of truncating the 
average quartz percentage. Another change involves removing the 
reference to Sec.  90.206 (Approved sampling devices; equivalent 
concentrations) and replacing it with Sec.  90.2. The requirements 
contained in revised Sec.  90.2 are similar to the standard

[[Page 10832]]

in existing Sec.  90.206. Also revised under the proposed rule is the 
example illustrating how a reduced standard is established when 
respirable dust associated with a Part 90 miner contains more than 10 
percent quartz under the proposed revised dust-standard setting 
procedures.
Section 90.102 Transfer; Notice
    MSHA is proposing no substantive changes in existing Sec.  90.102, 
except to clarify in the regulatory text the application of the 
transfer provision in paragraph (a) when a Part 90 miner is assigned to 
a different shift. To conform with MSHA's long-standing policy, the 
proposed rule permits assigning a Part 90 miner to a different shift 
under certain circumstances without violating paragraph (a) of Sec.  
90.102(a). Unlike the pay protection afforded Part 90 miners by Sec.  
90.103(b) which would be applied ``[w]henever a Part 90 miner is 
transferred * * *'' (emphasis added), the job and shift protections 
provided by existing Sec.  90.102(a) apply ``whenever a Part 90 miner 
is transferred in order to meet the respirable applicable dust standard 
* * *'' (emphasis added). The intent to limit the scope of job and 
shift protections under paragraph (a) of this section and the purpose 
of doing so were explained as follows in the preamble to the existing 
Part 90 rules:

    The operator may transfer a Part 90 miner without regard to 
these job and shift limitations if the respirable dust 
concentrations in the position of the Part 90 miner complies with 
the applicable dust standard, but circumstances require changes in 
job assignments at the mine. Reductions in workforce or changes in 
operational methods at the mine may be the most likely situations 
which would affect job assignments. Any such transferred Part 90 
miner would still be protected by all other provisions under this 
part. (45 FR 80761)
    In instances where operators need to reassign employees to 
accommodate unforseen situations and unexpected mine and market 
conditions, MSHA believes that some leeway should be provided to 
assist operators in placement of a Part 90 miner. (45 FR 80766)

    These explanations show that MSHA did not intend the provisions of 
existing paragraph (a) to apply when a Part 90 miner is working in a 
position that meets the applicable dust standard and, for legitimate 
business reasons, the operator assigns the miner to a new job or 
shift.\11\ On the other hand, when the reasons for changing a Part 90 
miner's shift or job involve maintaining compliance with the applicable 
dust standard, then the provisions of paragraph (a) apply and the miner 
is entitled to job and shift protections, unless these protections are 
waived in accordance with this standard. MSHA will continue to 
carefully scrutinize any changes in job or shift assignments for a Part 
90 miner to determine whether paragraph (a) of Sec.  90.102 applies 
because the change constitutes a transfer to meet the applicable dust 
standard and, if not, to determine if the change in the Part 90 miner's 
job or shift assignment was due in any part to action which could be 
characterized as improper under the Mine Act.
---------------------------------------------------------------------------

    \11\ As noted above, however, the other protections provided by 
Part 90 would apply. For example, on the new shift or in the new job 
there could be no reduction in the miner's pay and compliance would 
have to be maintained with the applicable dust standard and the 
sampling requirements.
---------------------------------------------------------------------------

Section 90.103 Compensation
    The proposed rule would redesignate existing paragraphs (c) through 
(f) as (d) through (g) and add new paragraph (c). Proposed new 
paragraph (c) clarifies MSHA's longstanding policy of not applying the 
Part 90 miner compensation provisions of existing paragraphs (a) and 
(b) of this section in situations where, after initial compliance with 
the applicable dust standard by the operator, the Part 90 miner on his 
or her own initiative applies for and accepts another job in a work 
area with an average respirable dust concentration at or below 1.0 mg/
m3.\12\ Under these circumstances, the miner has not waived Part 90 
status.\13\ Therefore, the issue being addressed by proposed paragraph 
(c) is how the Part 90 wage provisions of existing paragraphs (a) and 
(b), which would be retained under the proposed rule, should be 
interpreted when a Part 90 miner initiates and accepts a job change. 
For the following reasons, MSHA believes that the compensations 
provisions of Part 90 may be read to provide no compensation protection 
for a Part 90 miner under these circumstances.
---------------------------------------------------------------------------

    \12\ At mines where a job bidding procedure is in effect, use of 
the bidding procedure is not dispositive of whether a job change is 
initiated by the miner. The job bidding procedure is applicable to 
all job changes, including operator-initiated changes. Thus, factors 
relating to the intent and actions of the miner and the operator 
must be evaluated.
    \13\ Existing Sec. Sec.  90.104(a)(2) and (3) provide for waiver 
of Part 90 miner status when the miner applies for and accepts or 
retains a position known by the miner to exceed the applicable dust 
standard.
---------------------------------------------------------------------------

    Existing Sec.  90.103, which would be retained in its entirety 
under the proposed rule, protects a miner from any immediate reduction 
in hourly wage as a result of exercising the option. Where no transfer 
of the miner occurs after the option is exercised, paragraph (a) 
prescribes:

    The operator must compensate each Part 90 miner at not less than 
the regular rate of pay received by that miner immediately before 
exercising the option under Sec.  90.3.

    Existing Sec.  90.103(b) addresses compensation protection for a 
Part 90 miner when there is a transfer of the miner. It prescribes:

    Whenever a Part 90 miner is transferred, the operator must 
compensate the miner at not less than the regular rate of pay 
received by that miner immediately before the transfer.

    As defined by proposed Sec.  90.2, a transfer, ``by the operator'' 
would include, but is not limited to, an operator-initiated job 
reassignment in order to meet the applicable dust standard or a 
reassignment due to a realignment or reduction in the workforce. 
However, a miner-initiated job change does not necessarily constitute a 
transfer for purposes of compensation under Sec.  90.103(b). 
Accordingly, the compensation provision of Sec.  90.103(b) may be 
interpreted as not applicable to a job change initiated by a Part 90 
miner.
    The above interpretations of Sec. Sec.  90.103(a) and (b) are also 
consistent with statutory language. Section 101(a)(7) of the Mine Act 
addresses several specific matters relative to mandatory health and 
safety standards promulgated by MSHA and in relevant part provides:

* * * Where appropriate, the mandatory standard shall provide that 
where a determination is made that a miner may suffer material 
impairment of health or functional capacity by reason of exposure to 
the hazard covered by such mandatory standard, that miner shall be 
removed from such exposure and reassigned. Any miner transferred as 
a result of such exposure shall continue to receive compensation for 
such work at no less than the regular rate of pay for miners in the 
classification such miner held immediately prior to his transfer. * 
* * (emphasis supplied)

    Thus, section 101(a)(7) supports an interpretation that the 
compensation provisions of Sec. Sec.  90.103(a) and (b) do not apply 
where a Part 90 miner initiates a job change for reasons of job 
preference and that Sec.  90.103(b) is limited to job changes which are 
``a result of'' exposure to respirable coal mine dust.
    Accordingly when there is a Part 90 miner-initiated job change, the 
compensation provisions of Sec. Sec.  90.103(a) and (b) would not be 
applicable in the Part 90 miner's new job and the miner would be paid 
whatever the new job usually pays. Thus, for example: A miner exercised 
the Part 90 option when his or her job paid $10 per hour. If the

[[Page 10833]]

operator keeps the Part 90 miner in the same work position because 
compliance with the applicable dust standard is maintained, or if the 
operator transfers the miner to a new work position to achieve 
compliance, then the Part 90 miner cannot be paid less than the $10 per 
hour received immediately before exercising the option. If, then, the 
miner was to initiate and accept a change in work assignment to a job 
which paid $8.50 per hour, no pay protection would accompany the part 
90 miner to the new position and the miner would receive $8.50 per 
hour.
    The remainder of Part 90 provisions, however, would continue to 
apply to the Part 90 miner in the new work position. As noted earlier, 
a miner-initiated job change to a position which is at or below the 
applicable dust standard for a Part 90 miner does not constitute a 
waiver of Part 90 rights. Thus, in the new job the miner retains Part 
90 status and all other requirements of Part 90 continue in effect, 
including the operator's obligations to continuously maintain the 
applicable dust standard and to give MSHA notice whenever the miner's 
work assignment changes last longer than one shift.
    For purposes of consistency, redesignated paragraphs (e) and (g) 
have been revised to read as follows: ``* * * under paragraphs (a), (b) 
and (d) * * *'' and ``* * * in paragraphs (a), (b), (d), and (e) * * 
*,'' respectively.
Section 90.104 Waiver of Rights; Re-exercise of Option
    The proposed rule would retain the existing provisions of Sec.  
90.104, with some minor revisions for purposes of simplification. In 
paragraph (a)(2), ``exceeds the applicable dust standard'' would 
replace the statement beginning with ``* * * has an average respirable 
dust concentration * * *'' Paragraph (a)(3) would be revised by 
replacing the statement beginning with ``* * * average respirable dust 
concentration * * *'' with ``existing work position exceeds the 
applicable dust standard.'' Lastly, the section heading for Sec.  
90.3(e) has been removed from existing paragraphs (b) and (c).

Sections 90.201 through 90.207

Sampling Procedures

Section 90.201 Sampling; General Requirements
    MSHA is proposing to modify the general requirements for operator 
sampling of new or transferred Part 90 miners under existing Sec.  
90.201. Since MSHA would be responsible for collecting samples to 
determine if an operator has abated a noncompliant condition, the 
proposed rule would remove existing paragraph (d). The proposed rule 
would also revise and redesignate existing paragraphs (b) as (c), (c) 
as (f), and (e) as (d), revise paragraph (a), and add new paragraph 
(b).
    Revised paragraph (a) specifies the purpose of operator sampling 
under this proposed rule. While MSHA would be assuming responsibility 
for most of the sampling currently being carried out by the operator, 
revised paragraph (a) would continue to require operators to conduct 
sampling to verify that the working environment of a new or transferred 
Part 90 miner complies with Sec. Sec.  90.100 or 90.101 as required by 
existing Sec.  90.207, which has been redesignated as Sec.  90.204. 
Also, to minimize repetition and maintain consistency with virtually 
identical provisions in proposed amendments to Part 70, paragraph (a) 
would be modified by removing the reference to Part 74 approval (Coal 
Mine Dust Personal Sampler Units), and replacing it with ``approved 
sampling device,'' as defined under revised Sec.  90.2.
    Proposed new paragraph (b) would retain the requirements in 
existing Sec. Sec.  90.202(a) and (b) that sampling required under this 
part be conducted by an individual certified by MSHA and the manner by 
which a person would be certified. Therefore, existing Sec.  90.202(a), 
(b), and (c) would be removed.
    Since the objective of operator sampling proposed under this part 
is to verify that the assigned position of a new or transferred Part 90 
miner complies with the applicable dust standard, the sampling device 
would continue to be worn by each Part 90 miner as required by existing 
Sec.  90.201(b). However, under redesignated paragraph (c), the 
requirement that sampling devices ``remain operational during the 
entire shift or for 8 hours, whichever time is less'' would be removed. 
Instead, the sampling device would be operated portal-to-portal and be 
operational during the Part 90 miner's entire work shift, regardless of 
the number of hours worked, to ensure that the sampled Part 90 miner is 
not personally overexposed. That is, the sampling device would be 
turned ``ON'' when the Part 90 miner enters the mine and remain 
operational while traveling to the assigned work position, while 
performing normal work duties, and while traveling back to the mine 
entrance, at which time the device would be turned ``OFF.'' It should 
be pointed out that the duration of MSHA sample collection will 
continue to be limited to 480 minutes as has been the longstanding 
practice. Simply stated, the sampling device would be operated portal-
to-portal and remain operational during the entire shift or for 8 
hours, whichever time is less. The Agency solicits comments on the 
duration of MSHA sampling under the proposed rule.
    Unless otherwise directed by the district manager, the respirable 
dust samples will continue to be collected by placing the sampling 
device on the Part 90 miner; on the piece of equipment which the Part 
90 miner operates within 36 inches of the normal working position; or 
at a location that represents the maximum concentration of dust to 
which the Part 90 miner is exposed.
    Under redesignated paragraph (f), not only would the operator be 
required to submit the date but also the time when sampling required by 
this part would begin when requested by the district manager. This is 
necessary since operators may choose to sample any shift on the date 
provided to MSHA. Knowing the time of the scheduled sampling will 
enable MSHA to monitor operator sampling on a case-by-case basis to 
verify compliance with both the operating conditions and sampling 
requirements of this part.
    Finally, the requirement that operators take corrective action 
during the time for abatement fixed in a citation for violation of 
Sec. Sec.  90.100 or 90.101 specified in existing paragraph (d) of 
Sec.  90.201 would be transferred to proposed Sec.  90.207(b)(2). The 
requirement that the operator sample the affected Part 90 miner until 
five valid samples are taken under existing paragraph (d) would be 
removed since MSHA is proposing to revoke operator sampling 
requirements under existing Sec.  90.208.
Section 90.202 Approved Sampling Devices; Maintenance and Calibration
    In an effort to consolidate the requirements that address 
maintenance and calibration procedures of approved sampling devices, 
MSHA is proposing in Sec.  90.202(a) through (e) to retain the 
requirements in existing Sec.  90.203(a) and (b) and Sec.  90.204(a) 
through (e), with minor changes. These standards require the sampling 
device be maintained as approved and calibrated only by a certified 
person in accordance with MSHA Informational Report IR 1240 (1996). The 
process of certifying an individual for maintenance and calibration 
would remain unchanged. It would continue to require an individual to 
successfully complete the applicable MSHA examination. Scheduling 
information for MSHA training courses and examinations would be 
available from MSHA District Offices.

[[Page 10834]]

    These standards require approved sampling devices to be calibrated 
at a flowrate of 2.0 liters of air per minute. They also establish the 
flowrate and testing and examination requirements for approved sampling 
devices. Careful examination and testing of sampling devices would 
continue to be required immediately prior to the start of a shift 
during which samples would be collected for purposes of this proposed 
rule. This would include testing the battery voltage and examining all 
external components of the sampling devices to be used. Any necessary 
external maintenance to assure the sampling devices are clean and in 
proper working condition should be performed at this time by a 
certified person. Temporary certification of persons provided under 
existing Sec.  90.203(c) would not be retained under the proposal.
Section 90.203 Approved Sampling Devices; Operation; Air Flowrate
    Proposed Sec. Sec.  90.203(a) through (c) retains the operation and 
flowrate requirements for approved sampling devices in existing 
Sec. Sec.  90.205(a) through (d), with minor changes. Since MSHA has 
defined an approved sampling device in revised Sec.  90.2 to mean a 
device approved in accordance with part 74 of this title, proposed 
paragraph (a) excludes reference to part 74. Similarly, for purposes of 
simplification, reference to Sec.  90.202 (Certified person; sampling) 
would be removed and, wherever used, it would be replaced by certified 
person as defined in revised Sec.  90.2.
    MSHA believes that the two on-shift examinations of sampling 
devices under proposed paragraphs (b)(1) and (b)(2), which are 
identical to the examinations required under existing Sec.  90.205(b) 
and (c), continue to be an important part of a reasonable and prudent 
sampling program. The first examination would be made by a certified 
person during the second hour after the sampling devices are placed in 
operation. This examination would assure that each sampling device is 
operating properly and at the proper flowrate. If the proper flowrate 
is not maintained, necessary adjustments in the flowrate would be made 
at this time by the person certified to collect samples. The second 
examination would be made during the last hour of operation of the 
sampling devices. If the proper flowrate is not maintained, the 
certified person is required to make a notation on the dust data card 
for that sample stating that the proper flowrate was not maintained. 
Because it is unclear where on the dust data card such a notation 
should be made, proposed paragraph (c) would require all notations 
regarding failure to maintain proper flowrate or other events occurring 
during sampling that may impact the validity of the sample to be made 
on the back of the dust data card.
Section 90.204 Respirable Dust Sampling
    This section, previously titled ``Compliance sampling'' under 
existing Sec.  90.207, would be modified under the proposed rule and 
redesignated as Sec.  90.204. Since the operator sampling requirement 
under existing Sec.  90.208(a) would be revoked, the proposed rule 
would remove existing paragraph (b) and redesignate paragraph (a)(3) as 
(a)(2). The proposed rule would also add new paragraphs (b) and (c).
    Consistent with the proposed operator sampling requirements 
contained in revised Part 70, MSHA would also be assuming 
responsibility for all sampling for compliance and abatement purposes. 
This sampling is currently being carried out by the operator under 
existing Sec. Sec.  90.201(d) and 90.208(a). However, the proposed rule 
would continue to retain the existing provisions of Sec.  90.207, with 
major changes under redesignated Sec.  90.204. The objective of this 
provision is to maintain operator responsibility for verifying the 
suitability of the atmosphere in the position to which a new or 
transferred Part 90 miner would be assigned to work. This would assure 
that any new or existing Part 90 miner would be placed in an atmosphere 
which meets the applicable dust standard.
    Therefore, to determine if a new Part 90 miner is working in an 
area of the mine where the dust concentration during each shift does 
not exceed 1.0 mg/m\3\, the operator would be required to collect five 
valid samples within 15 calendar days after being notified by MSHA that 
a Part 90 miner is employed at the mine in accordance with proposed 
Sec.  90.201. The operator would also be required to collect five valid 
samples under proposed paragraph (a)(2) to verify the suitability of a 
work position to which a Part 90 miner was transferred under Sec.  
90.102. Valid samples are defined in the proposed rule as respirable 
dust samples collected and submitted as required by this part, and not 
voided by MSHA. Voided or invalid samples would not satisfy the 
sampling requirements and operators would be required to collect and 
submit additional samples. In addition, all samples required by this 
part would be required to be taken while the Part 90 miner is 
performing normal work duties. Failure to take the required number of 
valid samples under proposed Sec.  90.204 would constitute a violation. 
Consequently, it would be advantageous to collect and submit the 
samples required early during the specified 15-day period.
    While the proposed rule continues the operator requirement to 
collect five valid samples, the results would no longer be averaged to 
determine whether the applicable dust standard is being continuously 
maintained. Instead, consistent with proposed Sec.  72.500 of this 
title, each of the five valid sample will be compared to the applicable 
dust standard individually. Under this evaluation procedure, if all 
five samples are at or below the applicable dust standard, MSHA is 
confident that the Part 90 miner is being placed in an atmosphere which 
actually meets the standard. However, if any valid sample exceeds the 
applicable dust standard by at least 0.1 mg/m3, the operator 
would be required to immediately take corrective action and take an 
additional five valid samples from the environment of the affected Part 
90 miner within 15 days following receipt of notification from MSHA. 
The proposed rule permits the operator to meet the applicable dust 
standard in either of two ways: (1) By implementing control measures to 
lower the dust concentration in the Part 90 miners's existing assigned 
position; or (2) by transferring the Part 90 miner to another area of 
the mine that meets the standard.
    Since these samples are used to verify the suitability of the 
assigned work position, no operator samples will be used to make 
determinations as to compliance with the applicable dust standard under 
Sec. Sec.  90.100 or 90.101 of this part. Therefore, if any of the 
additional samples collected under proposed paragraph (b)(2) of this 
section exceed the applicable dust standard by at least 0.1 mg/
m3, the operator would be cited for failure to take 
corrective action under proposed paragraph (c) of this section.
Section 90.205 Respirable Dust Samples; Transmission by Operator
    MSHA is proposing no substantive changes to existing Sec.  90.209, 
except for removing reference to Sec.  90.202 (Certified person; 
sampling) from existing paragraph (c) to eliminate repetition since 
revised Sec.  90.201 specifies that all sampling required under this 
part must be conducted by a certified person, and redesignating it as 
Sec.  90.205. Existing paragraph Sec.  90.209(e) would be removed since 
all samples submitted by the operator under this part would be 
processed by MSHA. The proposed rule, like the existing rule, would 
require each Part 90 miner sample collected by

[[Page 10835]]

the operator to be transmitted to MSHA within 24 hours after the end of 
the sampling shift in containers provided by the manufacturer of the 
filter cassette. The need to verify the suitability of the Part 90 
miner's assigned work position in the shortest possible time requires 
that samples be sent promptly to MSHA for analysis.
    Each transmitted sample must be accompanied by a properly completed 
dust data card. All dust data cards submitted must be signed by a 
person certified to collect samples and must include that person's 
certification number. By signing the card, that person certifies that 
the sample was collected in accordance with the requirements of this 
part.
    To maintain program integrity, all samples transmitted by an 
operator would be considered by this proposed rule to fulfill the 
sampling requirements of this part. However, if operators wish to 
collect samples for other purposes, they would need to notify the 
district manager in writing or by electronic means prior to the 
intended sampling shift and identify each filter cassette to be used by 
its identification number. This prior notification is not required if 
non-approved sampling devices and filter cassettes are used by an 
operator for non-regulatory purposes.
Section 90.206 Respirable Dust Samples; Report to Operator and Part 90 
Miners
    Under the proposed rule, reporting provisions of existing Sec.  
90.210 would be revised and redesignated as Sec.  90.206. It specifies 
the type of sampling data and other related information the operator 
would be provided by MSHA on each Part 90 miner sampled by the operator 
or by MSHA. The Agency believes that the proposed reporting 
requirements are in the best interest of the Part 90 miner. These 
provisions promote miner awareness of the respirable dust conditions in 
the Part 90 miner's working environment by making available current 
information on the results of all sampling-related activities. This is 
consistent with the statutory intent that miners play a role in 
preventing unhealthy conditions and practices where they work. This 
approach is also consistent with the recommendations of the Advisory 
Committee regarding miner participation in the sampling process.
    In proposed paragraph (a), the phrase ``The Secretary shall provide 
the operator'' has been replaced with ``MSHA will provide.'' Paragraphs 
(a)(1) through (6) of the proposed rule retains the existing 
requirement regarding the types of data MSHA would be reporting on 
samples submitted by the operator, except for paragraph (a)(4) which 
would be removed since averaging of multiple valid samples would no 
longer be permitted under the proposed rule. Also, since MSHA would 
undertake sampling for compliance purposes, currently performed by the 
operator under existing Sec.  90.208, the results of MSHA samples would 
also be reported to the operator. The data report would include the 
location within the mine from which each Part 90 miner sample was 
collected; the equivalent concentration of respirable dust for each 
valid sample; the occupation code, and the reason for voiding any 
sample. In addition to providing data on individual samples, under 
proposed paragraph (7), the Agency would also furnish information on 
the dust control measures that were being used in the work position of 
the sampled Part 90 miner by providing a copy of completed MSHA Form 
2000-86 (Revised).
    Paragraph (b) of the proposed rule retains the existing provision 
of requiring the operator to provide a copy of the sample data report 
to the affected Part 90 miner but, for privacy reasons, prohibits the 
operator from posting the original or a copy of this report on the mine 
bulletin report.
Section 90.207 Violation of Respirable Dust Standard; Issuance of 
Citation; Action Required by Operator; and Termination of Citation
    Proposed Sec.  90.207 is a new requirement that addresses the 
circumstances under which MSHA would issue a citation for violation of 
the applicable dust standard. It also establishes the specific actions 
that an operator would be required to take within the time for 
abatement fixed in the citation. This proposed section also sets forth 
the conditions under which MSHA would terminate such citations.
    Under proposed paragraph (a), the operator would be cited for a 
violation of Sec.  90.100 or Sec.  90.101 when the equivalent 
concentration of a valid Part 90 miner sample collected by MSHA meets 
or exceeds the citation threshold value (CTV) listed in Table 70-2 of 
this title that corresponds to the applicable dust standard in effect. 
As discussed in section III.A.4. of the preamble, these measurements 
will be based on single-shift samples collected with approved sampling 
devices that will be operated portal-to-portal. The devices will remain 
operational during the entire shift or for 8 hours, whichever time is 
less, as has been the long-standing practice.
    The CTVs and an explanation of how they were derived was originally 
published in Federal Register notice of Feb. 3, 1998 (63 FR 5687), 
entitled ``Coal Mine Respirable Dust Standard Noncompliance 
Determinations.'' As explained in that notice and in Appendix C of the 
current notice of proposed rulemaking, each CTV was calculated so that 
citations would be issued only when a single-shift measurement 
demonstrates noncompliance at least at a 95 percent confidence level.
    The following example illustrates how MSHA would apply the CTVs to 
make noncompliance determinations. Suppose that a measurement of 1.27 
mg/m\3\ is obtained for a Part 90 miner under a 1.0-mg/m\3\ standard. 
Because the measurement meets or exceeds the CTV of 1.26 mg/m\3\ (the 
citation value for a 1.0-mg/m\3\ standard), a citation would be issued 
for exceeding the applicable dust standard on the shift sampled. The 
Part 90 miner's work position would be identified in the narrative of 
the citation as the affected working environment.
    MSHA believes that, because of the large ``margin of error'' 
separating each CTV from the corresponding applicable dust standard, 
use of the CTV table would provide ample protection against erroneous 
citations. This matter was fully explored in the analysis published in 
Appendix C of the February 3, 1998 notice (63 FR 5703-5709). That 
analysis showed that for exceptionally well-controlled environments, 
the probability that any given citation is erroneous will be 
substantially less than 5 percent. The analysis also showed that this 
probability is even smaller in environments that are not well 
controlled. Therefore, citations issued in accordance with the CTV 
table would be much more likely the result of an excessive dust 
concentration rather than a measurement error. With regard to the risk 
of erroneous failures to cite, MSHA concluded that ``the probability of 
erroneously failing to cite a case of noncompliance at a given sampling 
location is less than 50 percent when the applicable dust standard is 
exceeded on a significant proportion of shifts at that location'' (63 
FR 5709 above).
    MSHA has also concluded that using single-shift measurements for 
noncompliance determinations in accordance with the CTV table neither 
raises or lowers the applicable dust standard. Operators would continue 
to be required under Sec.  90.100 or Sec.  90.101 to continuously 
maintain compliance with the applicable dust standard, not merely at or 
below the CTV.
    As explained in the notice regarding single-shift measurements of 
respirable coal mine dust published elsewhere in today's Federal 
Register, the Mine Act requires MSHA to regulate exposures on

[[Page 10836]]

each shift individually. Since MSHA does not track the number of shifts 
each miner works over a lifetime, MSHA must, as a matter of practical 
necessity, protect miners by limiting their exposure on each shift. 
Furthermore, as explained in Sections VI and VII of the present notice, 
eliminating overexposures on individual shifts is beneficial to miners' 
health. For miners working where there is a pattern of recurrent 
overexposures on individual shifts, eliminating such overexposures is 
expected, over a working lifetime, to significantly reduce the risk of 
pneumoconiosis. Therefore, the Secretary has concluded that equivalent 
dust concentrations should be maintained at or below the applicable 
dust standard on each and every shift.
    If an operator is cited for a violation of the applicable dust 
standard, proposed paragraphs (b)(1), (b)(2), (b)(2)(i) and (b)(2)(ii) 
would require the operator to take specific actions within the time for 
abatement fixed in the citation. First, in order to provide immediate 
health protection, the operator would be required to make available 
approved respiratory equipment to the affected Part 90 miner that 
complies with existing Sec.  70.300. The operator would then determine 
the cause of the excessive dust concentration and take appropriate 
corrective action to gain compliance. As under the current Part 90 
rule, the proposed rule would permit the operator to achieve compliance 
in either of two ways: (1) By implementing control measures to reduce 
the dust levels in the Part 90 miner's work position; or (2) by 
transferring the affected Part 90 miner to work in another location at 
the mine where the concentration of respirable dust does not exceed the 
standard. Any Part 90 miner who is transferred to another position 
would continue to remain a Part 90 miner at the new position, even if 
the job is at a surface mine.
    If the operator chooses to lower dust levels in the Part 90 miner's 
assigned work position, proposed paragraph (b)(2)(i) would require the 
operator to notify the district manager in writing or by electronic 
means within 24 hours after implementing the control measures. Since 
MSHA would be assuming responsibility for compliance and abatement 
sampling under this proposed rule, this notice would enable MSHA to 
schedule and conduct follow-up sampling to determine whether the 
operator's corrective action(s) was effective to gain compliance.
    The requirement of proposed paragraph (b)(2(i) would not apply if 
the corrective action involved transferring the Part 90 miner to 
another work position to achieve compliance. Instead, the operator 
would be required to comply with Sec.  90.102(c) by giving the district 
manager written notice of the transfer and the date on which it is to 
be effective before such a transfer would be allowed to occur. This is 
necessary so that MSHA could (1) update its computerized management 
information system to permit the processing of the five operator 
samples taken from the Part 90 miner's new work position as required by 
proposed paragraph (b)(3) of this section and (2) schedule and conduct 
follow-up sampling for abatement purposes.
    After complying with Sec.  90.102(c), the operator would be 
required to sample the affected Part 90 miner until five valid samples 
were collected and submitted within the abatement period fixed in the 
citation. As discussed under proposed Sec.  90.204, the purpose for 
taking these samples is to verify the suitability of the particular 
working environment in which the Part 90 miner was placed. Therefore, 
MSHA does not intend to take enforcement action based on the results of 
operator samples, only for failure to take corrective action under 
proposed paragraph (b)(2) of this section. Under this proposed rule, 
only valid samples collected by MSHA would be used to abate a violation 
of Sec.  90.100 or Sec.  90.101.
    In order to determine if the operator abated the excessive dust 
violation, MSHA would collect one valid sample from the affected Part 
90 miner's position while he or she is performing normal work duties. 
As discussed under Sec.  90.201, the duration of MSHA sample collection 
would continue to be limited to 480 minutes as has been the long-
standing practice. If the MSHA abatement sample exceeds the applicable 
dust standard but is less than the appropriate CTV, MSHA may sample 
additional shifts to confirm the adequacy of the operator's corrective 
action. MSHA would consider a violation of the applicable dust standard 
to be abated and terminate the citation when the result of a valid MSHA 
sample is at or below the applicable dust standard. The subsequent 
action form would clearly and fully describe the action taken to abate 
the violation. If the violation was abated by reducing the dust levels 
in the Part 90 miner's work position, proposed paragraph (c)(1) would 
require the operator to submit a respirable dust control plan to the 
district manager for approval in accordance with Sec.  90.300 of this 
part, which has been retained under this proposed rule. A dust control 
plan would not be required to be submitted if compliance was achieved 
by transferring the Part 90 miner to another work position at the mine.
Section 90.208 Status Change Reports
    The proposed rule retains the existing provision of Sec.  90.220, 
which would be redesignated as Sec.  90.208, with some revision. It 
would require the operator to report in writing or by electronic means 
any change in status of a Part 90 miner that affects sampling to a 
designated MSHA District office within three working days after a 
status change has occurred. Knowing the status of every Part 90 miner 
will enable the Agency to carry out its sampling and monitoring of 
operator sampling activities in the most efficient and responsible 
manner. The operator would be in violation of Sec.  90.208 when the 
operator fails to comply with the sampling requirements of this part or 
MSHA was unable to carry out its sampling of a particular Part 90 miner 
for compliance purposes due to the unavailability of the Part 90 miner 
that was not reported by the operator as required.

Sections 90.300 and 90.301

Respirable Dust Control Plans

Section 90.300 Respirable Dust Control Plan; Filing Requirements; 
Contents
    The proposed rule retains the existing provisions of Sec.  90.300, 
which sets forth in detail when a dust control plan must be filed and 
the information that the operator must include in the plan. Although 
the language of part of paragraph (a) of the proposed rule differs from 
that of the existing section, the specific requirements are essentially 
the same. This change was made in the proposed rule for clarity and 
consistency with virtually identical provisions in existing Sec.  
71.300 of this title.
    If an operator abates the violation by implementing control 
measures that lower the dust in the Part 90 miner's work position, 
proposed paragraph (a) requires the operator to prepare a respirable 
dust control plan applicable to the Part 90 miner in the position 
identified in the citation. Each plan must be designed to continuously 
maintain the respirable dust level, in the Part 90 miner's assigned 
work position, at or below the applicable dust standard. This plan must 
be submitted to the district manager for approval within 15 days after 
the citation is terminated. A copy of the approved plan must be 
provided to the affected Part 90 miner. However, the operator is 
prohibited from posting the original or

[[Page 10837]]

a copy of the plan on the mine bulletin board.
    If, on the other hand, the operator abates a violation of the 
applicable dust standard by transferring the part 90 miner to another 
position at the mine, the operator is not required to submit a dust 
control plan to the district manager for approval.
    As under existing paragraph (b), the operator would be required to 
include details on the control measures that were implemented to reduce 
the dust and abate the violation, as well as any other provisions 
required by the district manager. The plan must also include the 
specific time, place and manner that the control measures would be 
used. Failure to do so would constitute a violation of this section.
Section 90.301 Respirable Dust Control Plan; Approval by District 
Manager; Copy to Part 90 Miner
    The proposed rule retains the existing provisions of Sec.  90.301, 
which specifies the criteria MSHA would use to approve the operator's 
dust control plan. Since MSHA would assume sampling of Part 90 miners 
for compliance purposes, the following phrase was inserted towards the 
end of paragraph (a): * * * ``the results of MSHA sampling and.'' Also, 
the proposed rule would add the word ``continuously'' to paragraph 
(a)(1) for consistency with Sec.  90.300(a), and replace the phrase 
``MSHA may take respirable dust samples to determine whether'' in 
paragraph (b) with ``MSHA will monitor the continued effectiveness of'' 
to reflect MSHA's assumption of sampling for compliance purposes.

V. Health Effects

A. Introduction

    For as long as miners have taken coal from the ground, many have 
suffered respiratory problems due to their occupational exposures to 
respirable coal mine dust. Long-term retention of coal mine dust in the 
lung causes chronic lung diseases including coal workers' 
pneumoconiosis (CWP), silicosis, and chronic obstructive pulmonary 
disease (COPD) (e.g., chronic bronchitis, emphysema, and airways 
obstruction). Coal workers' pneumoconiosis occurs in two stages: simple 
and complicated pneumoconiosis. Simple CWP is categorized into three 
levels of severity: 1, 2, and 3. Miners with simple CWP, especially the 
more advanced categories, have a substantially increased risk of 
developing complicated pneumoconiosis (more typically known as 
progressive massive fibrosis (PMF)). Progressive massive fibrosis can 
cause significant loss of lung function and give rise to respiratory 
symptoms (e.g., breathlessness, wheezing), and lead to disability and 
premature mortality. Overall, coal miners are at risk of increased 
morbidity and premature mortality arising from all of the chronic 
diseases associated with coal mine dust exposure.
    Elimination or reduction of coal mine dust exposure is the only 
effective way to prevent or minimize occupational lung disease among 
coal miners. However, routine screening affords the potential to 
prevent further development of disease among those, who despite dust 
control measures, still develop CWP. Pursuant to 42 CFR part 37, the 
National Institute for Occupational Safety and Health (NIOSH) operates 
a program for underground coal miners designed to detect early CWP. 
This screening program for CWP is termed the Coal Workers' X-ray 
Surveillance Program (CWXSP).
    In 1998, MSHA estimated that there were approximately 45,000 
underground coal miners and 39,000 surface coal miners (Mattos, 1999). 
A small percentage of the mining involved anthracite coal, the highest 
rank coal, while most involved bituminous coal which is a medium rank 
coal.
    There are complementary data sources, described below, which 
provide estimates of the prevalence of occupational respiratory disease 
among coal miners. Together these data demonstrate the progress over 
the last thirty years in the reduction of occupational respiratory 
disease among coal miners, as well as the need for further action to 
reduce occupational lung disease.
    In accordance with 30 CFR part 50, both surface and underground 
coal mine operators must report any known cases of occupational 
illnesses to MSHA. Under this requirement, mine operators reported 224 
cases of coal workers' pneumoconiosis in 1998 (Mattos, 1999). Of these, 
138 cases occurred among coal miners who worked underground, while the 
remaining 86 cases occurred among surface coal miners (Mattos, 1999). 
There were also 14 cases of silicosis, eight in underground mines, 
reported to MSHA in 1998 in accordance with 30 CFR part 50 (Mattos, 
1999).
    In the 1990s, MSHA conducted a one-time medical screening and 
surveillance program in various regions of the country. This program 
was designed to help more coal miners, especially surface coal miners, 
learn whether or not they had CWP, and to provide a more accurate 
estimate of the prevalence of simple CWP and PMF among these coal 
miners. Through this special program, MSHA tried to minimize obstacles 
that may prevent some miners from participating in respiratory 
diagnostic procedures. Nine geographical groups of miners were 
encouraged to participate in this x-ray program that was independent of 
the CWXSP (MSHA, Internal Chart, 1999). The study groups included eight 
active surface coal mining communities in Pennsylvania, Kentucky and 
West Virginia, as well as Poteau, Oklahoma and Gillette, Wyoming. A 
ninth group included underground miners in Kentucky. The process was 
designed to encourage miner participation by providing for a greater 
degree of anonymity than may be available under the NIOSH x-ray 
program. Across the eight surface groups surveyed, the prevalence rate 
of CWP among participants was 5.6% (130/2,305). The CWP prevalence rate 
among the participating underground Kentucky miners was 9.2% (37/404).
    Due to the different outreach initiatives number and type of 
participants in these various subgroups, relative to the population of 
today's coal miners, these data may not be representative of the 
overall prevalence of CWP among today's coal miners.
    The Secretary of Labor's Advisory Committee on the Elimination of 
Pneumoconiosis Among Coal Workers (Dust Advisory Committee, 1996) 
recommended that the CWXSP for pneumoconiosis include surface coal 
miners and independent contractors and that it increase underground 
coal miners' participation to at least 85 percent. In response, MSHA 
and NIOSH implemented the Miners' Choice Health Screening Program 
(Miners' Choice) in October 1999. The Miners' Choice program and Coal 
Workers' X-Ray Surveillance Program (CWXSP) identify cases of simple 
and complicated pneumoconiosis, including coal workers' pneumoconiosis 
and silicosis--hereafter referred to as ``CWP.'' All of the Miners'' 
Choice x-rays were processed using the same procedures and criteria 
used in the CWXSP in accordance with the requirements of 42 CFR part 
37.
    MSHA and NIOSH are conducting preliminary analyses of the first 
three years of the Miners' Choice program. These data and analyses are 
being handled, conducted, and reported pursuant to the DOL's and DHHS's 
respective Information Quality

[[Page 10838]]

Guidelines.\14\ Preliminary analyses of these data are expected in 
Spring 2003. The analyses will be made available to commenters through 
the MSHA and NIOSH Web sites, http://www.msha.gov and http://www.cdc.gov/niosh/homepage.html, respectively.
---------------------------------------------------------------------------

    \14\ Specifically, the information is maintained in a 
confidential manner, all methodologies for data processing are 
transparent, and all available records were included. This 
information is reliable and accurate, and is presented in a clear 
and objective manner, as required by the Department of Labor's 
Information Quality Guidelines and the Department of Health and 
Human Services' Guidelines for Ensuring the Quality of Information 
Disseminated to the Public.
---------------------------------------------------------------------------

    As of the end of fiscal year 2002, more than 19,500 active coal 
miners from 20 states voluntarily participated in Miners' Choice. The 
overall CWP prevalence rate for radiographic categories of simple CWP 
categories 1, 2, 3, and PMF combined was 2.8% (546/19,517) among miners 
examined in Miners' Choice during the 2000-2002 period. This is similar 
to the CWP prevalence rate of 2.25% for initial participants in the 
Miners' Choice Program reported in the 2000 NPRM (65 FR 42100). Among 
Miners' Choice participants, the CWP prevalence rate was higher among 
underground coal miners at 3.8% (356/9,265), than it was for surface 
coal miners, 1.8% (188/10,184). The CWP prevalence rate for independent 
contractors was 2.9% (2/68). These findings show that CWP continues to 
occur among coal miners working under the current program to control 
respirable coal mine dust, including quartz.
    Coal miners with simple CWP, particularly the advanced categories, 
are much more likely to develop life-threatening complicated CWP (i.e., 
progressive massive fibrosis, or PMF), than those with category 0 (ILO 
profusion categories of 0/0 or 0/1) (Cochrane, 1962; Hurley et al., 
1987; Hurley and Jacobsen, 1986; Hurley and Maclaren, 1987; Jacobsen, 
et al., 1971; McLintock, et al., 1971; and Morfeld, et al., 1992). In 
addition, epidemiological studies have shown that even among miners 
with category 0, those with a CWP profusion category suggesting 
pneumoconiosis (i.e., 0/1) are at increased risk of developing PMF 
compared to miners with a CWP profusion category of 0/0 (Hodous and 
Attfield, 1990 and McLintock, et al., 1971).
    Several studies provide consistent information relevant to this 
issue. In a study of miners who participated in round six (1990-1995) 
of the Coal Workers' X-Ray Surveillance Program (CWXSP), Althouse et 
al. (1998) found an average prevalence rate of 2.2% for simple CWP 
category 1 and higher among the 8,210 miners who reported beginning 
work in underground coal mines in 1973 or later. Miners who reported 
other prior dusty work were excluded from the analysis. Althouse et al. 
(1998) also report an overall decline in the CWP prevalence rates 
between 1970 and 1995. While this result is encouraging, it also 
demonstrates that pneumoconiosis is still occurring among miners who 
have worked only under the current applicable dust standard, and for 
less than a full working lifetime. The Althouse et al. (1998) study did 
not include estimates of exposure concentration, but the prevalence 
rates were shown to increase with tenure in mining (up to 22 years). In 
an earlier study, NIOSH compared the observed prevalences of CWP among 
miners who participated in rounds 3 and 4 of the CWXSP with the 
predicted prevalences from the epidemiological study by Attfield and 
Morring (1992b) (NIOSH 1995, Appendix L). That analysis included coal 
miners in the CWXSP who had started work between 1969 and 1986 and who 
had worked 10 or more years; exposure concentrations were estimated at 
or below the current standard. NIOSH found that the observed and 
predicted prevalences were similar, thus supporting the validity of the 
predictions from that epidemiological study. The findings from the 
Attfield and Morring (1992b) study are consistent with the findings 
from other epidemiological studies, including Attfield and Seixas 
(1995). Comparing the effect of miners' exposures received either 
before or after 1970, Attfield and Seixas (1995) found that exposure 
during both time periods contributed to the development of 
pneumoconiosis.
    In addition, the epidemiological studies are relevant to predicting 
the risks of occupational respiratory diseases among miners working 
today because the cumulative exposures of miners working at the current 
standard of 2.0 mg/m3 for a full 45-year working lifetime 
are well within the range of the data examined in these studies 
(Attfield and Seixas, 1995; Attfield and Morring 1992a,b; Attfield and 
Hodous, 1992; Seixas et al. 1992, 1993). Thus, risk estimates based on 
these studies do not require extrapolation beyond the range of the 
data. These epidemiological studies included quantitative estimates of 
miners' exposures to respirable coal mine dust and found statistically 
significant relationships between cumulative exposure and prevalence of 
pneumoconiosis or COPD. Despite several differences in the surveillance 
and epidemiological studies (e.g., exposure estimation and tenure, x-
ray readers, miner participation rates, and mines), the observed 
prevalence rates from the surveillance studies confirm the predicted 
prevalences from the epidemiological studies.
    The Mine Act of 1977 states:

    ``* * * in promulgating mandatory [health] standards which must 
adequately assure on the basis of the best available evidence that 
no miner will suffer material impairment of health or functional 
capacity even if such miner has regular exposure to the hazards 
dealt with by such standards for the period of his working life.'' 
Mine Act 101(a)(6)(A).

Findings from the CWXSP indicate an overall decline in the prevalence 
of CWP from 11% in the 1970s to 2.8% in the sixth round of CWXSP (1992-
1996) (NIOSH, Work-Related Lung Disease Surveillance Report, Table 2-
11, 1999). Even so, Miners' Choice, CWXSP, and MSHA's one-time medical 
surveillance programs in the 1990s consistently show prevalence of CWP 
to be at levels that cause concern. If patterns of overexposure to 
respirable coal mine dust remain unchanged for these coal miners, the 
prevalence of CWP would continue to increase, as their cumulative 
exposure to respirable coal mine dust increases over their coal mining 
careers.
    Both MSHA and NIOSH (Re-opening notice for the Determination of 
Respirable Coal Mine Dust published elsewhere in today's Federal 
Register; Criteria Document, 1995) find the current program for 
preventing overexposures to respirable coal mine dust is not sufficient 
to adequately prevent overexposures to respirable coal mine dust and 
protect the health of the coal miners.

B. Hazard Identification

1. Agent: Coal
    Coal is a fossil fuel derived from partial degradation of 
vegetation. Through its combustion, energy is produced which makes coal 
a valuable global commodity. It has been estimated that over one-third 
of the world uses energy provided by coal (Manahan, 1994). 
Approximately 1,800 underground and surface coal mines are in operation 
in the United States annually producing slightly over a billion short 
tons of coal (Mattos, 1999).
    Coal may be classified on the basis of its type, grade, and rank. 
The type of coal is based upon the plant material (e.g., lignin, 
cellulose) from which it originated. The grade of coal refers to its 
chemical purity. Although coal is largely carbon, it may also contain 
other elements such as hydrogen, oxygen,

[[Page 10839]]

nitrogen, and sulfur. ``Hard'' coal refers to coal with a higher carbon 
content (i.e., 90-95%) than ``soft'' coal (i.e., 65-75%). Coal rank 
relates to geologic age, indexed by its fixed carbon content, down to 
65%, and then by its heating value. Volatile matter varies inversely 
with the fixed carbon value. The most commonly described coal ranks 
include lignite (low rank), bituminous coal (medium rank), and 
anthracite (high rank) (Manahan, 1994).
2. Physical State: Coal Mine Dust
    Aerosols are a suspension of solid or liquid particles in air 
(Mercer, 1973); they may be dusts which are solid particles suspended 
in the air. Coal dust may be freshly generated or may be re-suspended 
from surfaces on which it is deposited in mines. As discussed below, 
coal mine dust may be inhaled by miners, depending upon the particle 
size.
    Coal mine dust is a heterogenous mixture, signifying that all coal 
particles do not have the same chemical composition. The particles are 
influenced by the type, grade, and rank of coal from which they were 
generated (Manahan, 1994). Irrespective of differences in coal 
characteristics, these dusts are water-insoluble, which is important 
biologically and physiologically. Unlike soluble dusts which may 
readily pass into the respiratory system and be cleared via the 
circulatory system, insoluble dusts may remain in the lungs for 
prolonged periods of time. Thus, a variety of cellular responses may 
result that could eventually lead to lung disease.
3. Biological Respirable Coal Mine Dust
    The principal route of occupational exposure to respirable coal 
mine dust occurs via inhalation. As a miner breathes, coal mine dust 
enters the nose and/or mouth and may pass into the mid airways (e.g., 
bronchi, terminal bronchioles) and lower airways (e.g., respiratory 
bronchioles, alveolar ducts).
    Coal mine dust has a size distribution that is estimated to range 
between 1 and 100 micrometers ([mu]m) (1 [mu]m = 10-6 m) 
(Silverman, et al., 1971). The size of coal particles is critical in 
determining the level of the respiratory tract at which deposition and 
retention occur (American Conference of Governmental Industrial 
Hygienists, 1999; American Industrial Hygiene Association, 1997).
    Particles that are greater than 10 [mu]m are largely filtered in 
the nasal passages. However, it has long been known that some particles 
greater than 10 [mu]m in size, can be inhaled, and that some of these 
particles can reach the alveoli of the lungs (Lippman and Albert, 
1969). According to the British National Coal Board, ``particles as 
large as 20 microns (i.e., micrometers ([mu]m)) mean diameter may be 
deposited, although most `lung dust' lies in the range below 10 microns 
diameters'' (Goddard, et al., 1973). Particles less than 10 [mu]m in 
size easily move throughout the respiratory tract. As particle size 
decreases from 10 to 5 [mu]m, however, there is greater penetration 
into the mid and lower regions of the lung. Particles that are 
approximately 1-2 [mu]m are the most likely to be deposited in the lung 
(American Conference of Governmental Industrial Hygienists, 1999; 
Mercer, 1973). During mouth breathing, there may be a slight upward 
shift in the particle deposition curve such that 2-3 [mu]m-sized 
particles are the most likely to be deposited in the respiratory tract 
(Heyder, et al., 1986). Irrespective of nasal or mouth breathing, the 
potential respiratory tract penetration of particles less than 10 [mu]m 
in size is important because particles in the respirable size range 
deposit in the deep lung where clearance is much slower.
    For the purposes of this rule, ``respirable dust'' is defined as 
dust collected with a sampling device approved by the Secretary of 
Labor and the Secretary of the Department of Health and Human Services 
(DHHS) in accordance with 30 CFR Part 74 (Coal Mine Dust Personal 
Sampler Units). In practice, the coal mine dust personal sampler unit 
has been used in the U.S. The particles collected with an approved 
sampler approximate that portion of the dust which may be deposited in 
the lung (West, 1990; 1992). It does not, however, indicate pulmonary 
retention (i.e., those particles remaining in the lung). For those 
particles that are deposited in the lung, clearance mechanisms normally 
operate to assist in their removal. For example, within the thoracic 
(tracheal-bronchial) region of the lung, cilia (i.e., hairlike 
projections) line the airways and are covered by a thin layer of mucus. 
They assist in particle clearance by beating rhythmically to project 
particles toward the throat where they may be swallowed, coughed, 
sneezed, or expectorated. This rhythmic beating action is effective in 
removing particles fairly quickly (i.e., hours or days). Within the 
alveolar region of the lung, particles may be engulfed by pulmonary 
macrophages. These large ``wandering cells'' may remove particles via 
the blood or lymphatics. This process, unlike the movement of the cilia 
is much slower (i.e., months or years). Thus, some particles, 
particularly those that are insoluble, may remain in the alveolar 
region for long periods of time, despite the fact that pulmonary 
clearance is not impaired. It is the pulmonary retention of coal mine 
dust which may be the impetus for respiratory disease.
    It is also important to note that silica may be present in the coal 
seam, within dirt bands in the coal seam, and in rock above and below 
coal seams. Of the silica found in coal mines, quartz is the form which 
is found. Thus, quartz may become airborne during coal removal 
operations (Manahan, 1994). Miners may inhale dust that is a mixture of 
quartz and coal. MSHA is concerned with the inhalation of quartz since 
it may be deposited in the lungs of miners and produce silicosis. This 
is a restrictive lung disease which is characterized by a stiffening of 
the lungs (West, 1990; 1992). Silicosis has been seen in coal miners 
(e.g., surface miners, drillers, roofbolters) (Balaan, et al, 1993). 
Silicosis may develop acutely (i.e., 6 months to 2 years) following 
intense exposure to high levels of respirable crystalline quartz. 
Silicosis has also been observed in coal miners following chronic 
exposure (i.e., 15 years or more), but may be accelerated (i.e., 7-10 
years) in some cases (Balaan, et al, 1993). Silicosis is irreversible 
and may lead to other illnesses and premature mortality. People with 
silicosis have increased risk of pulmonary tuberculosis infection and 
an increased risk of lung cancer (Althouse, et al., 1995; International 
Agency for Research on Cancer, 1997). MSHA's current standard of 2.0 
mg/m3 for respirable coal dust requires that quartz levels 
in the respirable coal mine dust be 5% or lower. Otherwise, the 2.0 mg/
m3 respirable coal dust exposure limit does not apply and 
must be adjusted downward for percentage of quartz. If respirable coal 
mine dust contains more than 5% quartz, then the following formula is 
applied (30 CFR 70.101; 30 CFR 71.101).
Respirable dust standard (mg/m3)= {(10)/(% Quartz){time} 
    The intent of this formula, as prescribed by the Secretary of 
Health, Education, and Welfare in 1971, whenever the respirable coal 
mine dust in the mine atmosphere of the active workings contains more 
than five percent quartz, is to maintain miner exposures to quartz 
below 0.1 mg/m3 (100 [mu]g/m3).\15\
---------------------------------------------------------------------------

    \15\ The applicable dust standard for intake air in Sec.  
70.100(b) and for miners who have exercised rights under Part 90 
regulations in Sec.  90.100 is 1.0 mg/m3. Those standards 
are also lowered if the quartz content of the respirable coal mine 
dust exceeds 5 percent. However, no effect occurs until the quartz 
content exceeds 10 percent.

---------------------------------------------------------------------------

[[Page 10840]]

C. Health-Related Effects of Respirable Coal Mine Dust

1. Description of Major Health Effects
    Consistently, epidemiological studies have demonstrated miners to 
be at risk of developing respiratory symptoms, a loss of lung function, 
and lung disease as a consequence of occupational exposure to 
respirable coal mine dust. As noted previously, risk factors include 
type(s) of dust, dust concentration, duration of exposure, age of the 
miner (often measured as age at time of medical examination), and coal 
rank.
a. Simple Coal Workers' Pneumoconiosis (Simple CWP) and Progressive 
Massive Fibrosis (PMF)
    In earlier stages of pneumoconiosis the term, ``simple coal 
workers' pneumoconiosis'' (simple CWP), has been used, while in more 
advanced stages, the terms ``complicated CWP'' and PMF have been used 
interchangeably. Simple CWP and PMF involve the lung parenchyma and are 
produced by deposition and retention of respirable coal dust in the 
lung.
    To determine if a miner has simple CWP or PMF, chest x-rays are 
taken and classified by a certified radiologist or reader. Opacities 
(both irregular and rounded) are identified on chest films and then 
classified using a scale of 0 through 3 (e.g., simple CWP category 1), 
where higher category values indicate increasing concentration of 
opacities. In some instances, two category values may be given. For 
example, simple CWP category 2/3 signifies that the reader decided the 
film was category 2, but suspected that it might have been category 3. 
The International Labour Office (ILO) has provided a full description 
of the criteria for these classifications (ILO, 1980).
    Studies have shown that the prevalences of both small rounded and 
small irregular opacities increase with increasing coal mine dust 
exposure (Amandus et al., 1976; Cockcroft et al., 1983; Collins et al., 
1988). Miners with small opacities (rounded and/or irregular) on their 
chest x-rays were more likely to report chronic cough and phlegm, and 
breathlessness, than miners without small opacities (category 0/0) 
(Collins et al., 1988). This effect was more common among miners with 
predominately small rounded opacities (Collins et al., 1988; Rae et 
al., 1971). Small irregular opacities have been associated with 
impaired lung function (Amandus et al., 1976; Cockcroft et al., 
1982b,c; Collins et al., 1988). The pattern of lung function impairment 
reported by Collins et al. (1988) was consistent with that typically 
associated with dust exposure in coal miners, and was distinctly 
different from the pattern observed among smokers.
    Because simple CWP represents an early stage of a progressive 
disease, miners who have had a chest x-ray classified as ILO category 1 
or greater are more likely than those with a clear x-ray (category 0) 
to progress to the more severe stages of the disease, including the 
complicated form, PMF (categories A, B, or C) (Cochrane, 1962; 
Jacobsen, et al., 1971; McLintock, et al., 1971; Morfeld et al., 1992; 
Balaan, et al., 1993). In addition, miners with simple CWP were found 
to have an increased risk of dying from pneumoconiosis (as the 
underlying or a contributing cause on the death certificate), and this 
risk tended to increase with increasing radiographic category (Kuempel 
et al., 1995).
    Progressive massive fibrosis (PMF) is associated with decreased 
lung function and increased premature mortality (Rasmussen, et al., 
1968; Atuhaire, et al., 1985; Miller and Jacobsen, 1985; Attfield and 
Wagner, 1992). Progressive massive fibrosis is also associated with 
increases in respiratory symptoms such as chest tightness, cough, and 
shortness of breath. Miners with PMF also have an increased risk of 
acquiring infections and pulmonary tuberculosis (Petsonk and Attfield, 
1994; Yi and Zhang, 1996). Finally, miners with PMF have an increased 
risk of right-side heart failure (i.e., cor pulmonale) (Cotes and 
Steel, 1987).
b. Other Health Effects
    During a medical examination, a miner may be questioned by his/her 
physician about symptoms such as cough, phlegm production, chest 
tightness, shortness of breath, and wheezing. Occupational physicians 
may also conduct pulmonary function tests using spirometry or 
plethysmography. Pulmonary performance may be assessed via repeated 
measurements of lung volumes and capacities, such as the forced 
expiratory volume in one second (FEV1), vital capacity (VC), forced 
vital capacity (FVC), residual volume (RV), and total lung capacity 
(TLC) (West, 1990; 1992). Changes in lung volumes and capacities may 
indicate a loss of the integrity of the lung (i.e., respiratory 
system). More importantly, they can provide information for diagnosis 
of diseases affecting the airways and/or elasticity of the lung (i.e., 
obstructive vs. restrictive lung disease)(West, 1990; 1992).
    The term, chronic obstructive pulmonary disease (COPD), refers to 
three disease processes that are often difficult to properly diagnose 
and differentiate: Chronic bronchitis, emphysema, and asthma (Coggon 
and Taylor, 1998; Garshick, et al., 1996; West, 1990; 1992). As 
indicated by several studies, the exposure of miners to respirable coal 
mine dust places them at increased risk of developing COPD. 
Furthermore, COPD may occur in miners with or without the presence of 
simple CWP or PMF.
    COPD is characterized by airflow limitations, and thus there is a 
loss of pulmonary function. As in simple CWP or PMF, a miner with COPD 
may have a variety of respiratory symptoms (e.g., shortness of breath, 
cough, sputum production, and wheezing) and may be at increased risk of 
acquiring infections. COPD is associated with increased premature 
mortality (Hansen, et al., 1999; Meijers, et al., 1997).
    Briefly, in chronic bronchitis and in asthma, there is excess 
mucous secretion in the mid to lower airways (West, 1990; 1992). In 
contrast, emphysema is characterized by dilatation (enlargement) of 
alveoli that are distal to the terminal bronchioles, which leads to 
poor gas exchange (i.e., poor transfer of oxygen and carbon dioxide). 
Additionally, there is a breakdown of the interstitium between the 
alveoli. These pathological changes may be confirmed upon autopsy. With 
asthma, the airflow limitations may be partially or completely 
reversible, while they are only partially reversible with chronic 
bronchitis and emphysema.
    The Mine Safety and Health Administration (MSHA) and the NIOSH 
recognize that respiratory symptoms, loss of lung function, and COPD 
may impair the ability of a miner to perform his/her job and may 
diminish his/her quality of life (65 FR 49215). Additionally, miners 
having such health effects are at increased risk of morbidity (e.g., 
from cardio-pulmonary disease, infections) and premature mortality.
2. Toxicological Literature
    To better understand the human health effects of exposure to 
respirable coal mine dust and to more fully characterize the associated 
risks, it is important to consider data that have been obtained in 
animal based toxicological studies. To date, sub-acute studies (a study 
with a duration of 30 days, or less, in which multiple exposures of the 
same agent are given) and chronic studies (a study with a duration of 
more than 3-months, in which multiple exposures of same agent are 
given) attempted to mimic miners'

[[Page 10841]]

exposures. Inhalation was generally the route of exposure, although 
several studies have also employed instillation techniques (i.e., a 
method which places a known quantity of dust into the trachea or 
bronchi).
    Most recent toxicological studies have been short-term studies, 
largely focusing on ``lung overload'' (Sipes, 1996; Oberdorster, 1995; 
Morrow, 1988, 1992; Witschi, 1990), species-dependent lung responses 
(Nikula, et al., 1997a,b; Mauderly, 1996; Lewis, et al., 1989; Moorman, 
et al., 1975), and particle size-dependent lung inflammation (Soutar, 
et al., 1997). The data have shown that pulmonary clearance of 
particles may become impaired, potentially leading to inflammatory and 
other cellular responses in the lung. Although overloading has not been 
demonstrated in humans, the finding of reduced lung clearance among 
retired U.S. coal miners (Freedman and Robinson, 1988) is consistent 
with this possibility.
    The data from Moorman, et al. (1975), Lewis, et al. (1989), and 
Nikula, et al. (1997a,b) are noteworthy for several reasons. First, 
these groups of investigators conducted chronic inhalation toxicity 
studies (i.e., chronic bioassays). This is important since miners' 
exposures also occur via inhalation, and over a working lifetime. 
Secondly, the investigators used an exposure concentration of 2.0 mg/
m3 in their bioassays. As noted above, this is the current 
MSHA standard for respirable coal mine dust. Thirdly, the exposures 
involved nonhuman primates, whose responses are thought to closely 
mimic those of man. Some of the key findings of these studies included: 
deposition of coal dust in the animals' lungs, retention of coal dust 
in alveolar tissue, altered lung defense mechanisms, reduced pulmonary 
airflows, and hyperinflation of the lungs. One of the shortcomings of 
these studies is that complete dose-response relationships were not 
developed. However, at higher exposure concentrations, greater effects 
may be expected which is a basic tenet of toxicology. Thus, at exposure 
concentrations above 2.0 mg/m3, MSHA and NIOSH believe that 
more severe obstructive lung disease may occur (65 FR 42078).
3. Epidemiological Literature
    Epidemiological studies have consistently demonstrated the serious 
health effects of exposure to high levels of respirable coal mine dust 
(i.e., above 2.0 mg/m3) over a working lifetime. Table V-2 
lists epidemiological studies since 1986 whose results will be 
discussed on the basis of the type of observed health effect. Studies 
completed even earlier including the early work of Cochrane (1962), 
McLintock, et al. (1971), and Jacobsen, et al. (1971) demonstrated the 
adverse health effects (e.g., simple CWP, PMF) of respirable coal mine 
dust in British coal miners.
    Both early and recent studies have shown that the lung is the major 
target organ (i.e., organ in which toxic effects occur) when exposure 
to respirable coal mine dust occurs. As seen in Table V-2, numerous 
studies of miners have been conducted. Recent U.S. studies were 
conducted using data from one or more of the first four rounds of the 
National Study of Coal Workers' Pneumoconiosis (NSCWP), and have 
provided extensive data on miners' health. Many of these studies 
demonstrated that miners are at increased risk of multiple, concurrent 
respiratory ailments (Attfield and Seixas, 1995; Kuempel, et al., 1997; 
Meijers, et al., 1997; Seixas, et al., 1992) .

    Table V-2.--Respirable Coal Mine Dust Epidemiological Studies, by
                 Reported Outcomes from 1986 to Present
------------------------------------------------------------------------
             Studies                         Reported outcomes
------------------------------------------------------------------------
Meijers, et al., 1997............  PMF, SCWP, COPD, LLF
Bourgkard, et al., 1998..........  PMF, SCWP, LLF, RS
Kuempel, et al., 1997*...........
Maclaren, et al., 1989...........
Kuempel, et al., 1995*...........  PMF, SCWP, COPD
Love, et al., 1997...............  PMF, SCWP, LLF
Love, et al., 1992...............
Althouse, et al., 1998*..........  PMF, SCWP
Attfield and Morring,1992b*......
Attfield and Seixas, 1995*.......
Goodwin and Attfield, 1998*......
Hodous and Attfield, 1990*.......
Hurley and Jacobsen, 1986........
Hurley and Maclaren, 1987; 1988
Hurley, et al., 1987.............
Morfeld, et al., 1997............
Starzynski, et al., 1996.........
Yi and Zhang, 1996...............
Collins, et al., 1988............  SCWP, COPD, LLF, RS
Morfeld, et al., 1997............  SCWP
Cockcroft and Andersson, 1987....  SCWP, COPD, LLF
Wang, et al., 1997...............
Leigh, et al., 1994..............  COPD, LLF, RS
Marine, et al., 1988.............
Seixas, et al., 1993.............
Soutar and Hurley, 1986..........
Attfield and Hodous, 1992*.......  LLF, RS
Carta, et al., 1996..............
Henneberger and Attfield,1997*...
Henneberger and Attfield,1996*...
Lewis, et al., 1996..............
Seixas, et al., 1992*............

[[Page 10842]]

 
Hansen, et al.,..................  1999 LLF
Weiss, et al., 1995..............
------------------------------------------------------------------------
COPD: Chronic obstructive pulmonary disease.
SCWP: Simple coal workers' pneumoconiosis.
LLF: Loss of lung function.
PMF: Progressive massive fibrosis.
RS: Respiratory symptoms.
* Studies of U.S. Miners Who Participated in the National Study of Coal
  Workers' Pneumoconiosis (NSCWP).

a. Simple Coal Workers' Pneumoconiosis (Simple CWP) and Progressive 
Massive Fibrosis (PMF)
    Studies following Cochrane (1962) and McLintock et al. (1971) have 
confirmed that the risk of PMF increases with increasing category of 
simple CWP (Hurley and Jacobsen, 1986; Hurley, et al., 1987; Hurley and 
Maclaren, 1988; Hodous and Attfield, 1990). However, the risk of PMF 
was greater than previously predicted among miners with simple CWP 
category 1 or without simple CWP (i.e., category 0) (Hurley, et al., 
1987). The risk of PMF increased with increasing cumulative exposure, 
regardless of the initial category of simple CWP (Hurley, et al., 
1987), indicating that reducing dust exposures is a more effective 
means of reducing the risk of PMF than reliance on detection of simple 
CWP.
    Attfield and Seixas (1995) have demonstrated a relationship between 
cumulative exposure to respirable coal mine dust and predicted 
prevalence of pneumoconiosis (i.e., simple CWP, PMF). Two strengths of 
this study include the quantitative description of exposure-response 
among both miners and ex-miners (who had worked approximately 13-40 
years in mining) and the fact that these data represent recent 
conditions experienced by miners in the U.S. They studied a group of 
approximately 3,194 men who worked in underground bituminous coal 
mines. The U.S. miners and ex-miners had participated in Round 1 (1970-
1972) or Round 2 (1972-1975) of the NSCWP and were examined again in 
Round 4 (1985-1988). The study population excludes 86 miners for whom 
there was missing exposure data or unreadable x-rays. Chest x-rays were 
read to determine the number of cases of simple CWP and PMF. Attfield 
and Sexias (1995) used two or three B readers to identify the profusion 
of radiographic opacities based on the ILO classification scheme. The 
most inclusive category defined in their paper was CPW 1+ which 
includes simple CWP categories 1, 2, and 3, as well as PMF. Dust 
exposure estimates were generated from measurements of dust 
concentrations as well as from work history. A logistic (or logit) 
regression model was used to estimate prevalence of simple CWP and PMF. 
In this statistical analysis, proportions are transformed to natural 
logarithmic values, i.e., y = ln [p/(1-p), before a linear model is fit 
to the data (Armitage, 1977). The logistic model assumes that the data 
have a binomial distribution (e.g., presence or absence of PMF) for a 
given set of covariate values (e.g., age, coal rank, dust exposure, 
pack-years of smoking). Using logistic modeling, relationships were 
developed between cumulative dust exposure and prevalence of simple CWP 
(category 1+, category 2+) and PMF. These relationships were the key 
strengths of the Attfield and Seixas study and serve as the basis for 
the quantitative risk assessment (QRA) of this rule.
    The recent paper of Kuempel, et al. (1997) has provided a detailed 
discussion and quantitative presentation of excess risks associated 
with respirable coal dust exposures. Their study was based upon results 
from previous studies of some 9,000 underground coal miners who 
participated in the NSCWP (Attfield and Morring, 1992b; Attfield and 
Seixas, 1995). Kuempel, et al. estimated excess (exposure-attributable) 
prevalence of simple CWP and PMF (i.e., number of cases of disease 
present in a population at a specified time, divided by the number of 
persons in the population at that specified time). Point estimates of 
excess risk of PMF ranged from 1/1000 to 167/1000 among miners exposed 
at the current MSHA standard for respirable coal mine dust. These 
estimates were based upon dust exposure that occurred over a miner's 
working lifetime (e.g., 8 hours per day, 5 days a week, 50 weeks per 
year, over a period of 45 years). Actual occupational lifetime exposure 
may be more, due to extended work shifts and work weeks. The point 
estimates of PMF presented by Kuempel, et al. (1997) were related to 
coal rank, where higher estimates (e.g., 167/1000) were obtained for 
high-rank coal (anthracite coal) and somewhat lower estimates were 
obtained for medium/low rank bituminous coal (e.g., 21/1000). Within 
each coal rank, the estimates of simple CWP cases were at least twice 
as high as those for PMF (e.g., 167/1000 PMF vs. 380/1000 simple 
CWP=1).
    The data of Attfield and Seixas (1995) and Kuempel, et al. (1995; 
1997) were consistent with previous data of Attfield and Morring 
(1992b) who reported relationships between estimated dust exposure and 
predicted prevalence of simple CWP or PMF. They also noted that 
exposure-response relationships were steeper for higher ranks of coal 
such as anthracite, and concluded that the risks for anthracite miners 
appeared to be greater than for miners exposed to lower rank coal dust. 
Attfield and Morring (1992b) used similar methods as described above 
(i.e., logistic modeling), but included miners from Round 1 of the 
NSCWP (1969-1971); thus representing an earlier time point in the NSCWP 
when the respirable coal mine dust concentrations were much higher than 
they are today.
    Recently, Goodwin and Attfield (1998) reported that there were 
concerns regarding methodological inconsistencies across surveys given 
during the four rounds of the NSCWP. In particular, they noted the 
discordance in classification of simple CWP and PMF among readers of 
chest films. Despite potential discordance, Goodwin and Attfield (1998) 
have confirmed previous findings of a decline in simple CWP prevalence 
from 1969 to 1988. Yet, these analyses also demonstrated that simple 
CWP has not been eliminated. The Round 4 prevalence rates were 3.9 
percent for simple CWP category 1 and higher, and 0.9 percent for 
category 2 and higher. This illustrates the need for continued efforts 
to reduce dust exposures.
    Given the current system for monitoring exposures and identifying 
overexposures in the U.S., miners are at increased risk of developing 
simple

[[Page 10843]]

CWP and PMF from a working lifetime exposure to respirable coal mine 
dust (Althouse et al. 1998, Attfield and Seixas, 1995; Attfield and 
Morring, 1992b; Goodwin and Attfield, 1998; Kuempel, et al. 1997, 
1995). Whenever overexposures (i.e., excursions above the applicable 
dust standard) occur, the long-term mean exposure of miners may be 
increased, thereby causing an upward shift on the exposure-response 
curve. Such a shift then places these overexposed coal miners at 
increased risk of developing and dying prematurely from simple CWP and 
PMF.
    The Attfield and Seixas epidemiological study (1995) is the most 
appropriate to use in estimating the benefit of reduction of 
overexposures. The authors applied scientific rigor to the collection, 
categorization, and analyses of the radiographic evidence for the group 
of 3,194 underground bituminous coal miners who participated in Round 
4, 1985-1988, of the National Study of Coal Workers' Pneumoconiosis 
(NSCWP). Radiologic evidence was carefully collected and analyzed by 
multiple independent, NIOSH certified B readers to identify stages of 
simple CWP and PMF. In the targeted population of 5,557 miners, the 
participating miners (3,280) were similar to the non-participants 
(2,277) with regard to age at the first medical examination and 
prevalence of simple CWP category 1 or greater. The non-participants 
had worked slightly longer, yet had lower prevalence of simple CWP 
category 2 or greater, than the participants. This study describes the 
differences among current miners and ex-miners (health-related or job-
related) in the relationships between the estimated cumulative exposure 
to respirable coal mine dust and prevalence of simple CWP category 1 or 
greater. Such data and relationships were not available in other U.S. 
studies and non-U.S. studies.
    A potential limitation in the U.S. studies is the possible bias in 
the exposure data, which has been the subject of several studies (Boden 
and Gold, 1984; Seixas et al., 1991; Attfield and Hearl, 1996). An 
advantage of the Attfield and Seixas 1995 study (and the earlier 
studies based on the same data set) is that the larger mines included 
in these epidemiological studies were shown to have exposure data with 
relatively small bias (Attfield and Hearl, 1996). Another limitation in 
exposure data used in the U.S. studies is that the airborne dust 
concentrations used to estimate individual miners' cumulative exposures 
to respirable coal mine dust were based on average concentrations 
within job category (these average values were combined with data of 
each individual miner's duration employed in a given job). The earlier 
U.S. exposure-response studies of miners participating in the first 
medical survey of the NSCWP (Attfield and Morring, 1992b; Attfield and 
Hodous, 1992; Kuempel, et al., 1995) relied primarily on exposure 
measurements from a dust sampling survey during 1968-1969 to estimate 
miners' exposures before 1970 (Attfield and Morring, 1992a). An 
advantage of the Attfield and Seixas 1995 study is that, in addition to 
the pre-1970 exposure estimates, more detailed exposure data were 
available to estimate miners' exposures from 1970 to 1987, during which 
the mean airborne concentrations were stratified by mine, job, and year 
(Seixas, et al., 1991).
    The most complete exposure data available are those for coal miners 
in the United Kingdom (Hurley, et al., 1987; Hurley and Maclaren, 1987; 
Soutar and Hurley, 1986; Marine, et al., 1988; Maclaren, et al., 1989). 
These studies include medical examinations and individual estimates of 
exposure for more than 50,000 miners for up to 30 years. The U.S. 
studies are consistent with these U.K. studies in demonstrating the 
risks of developing occupational respiratory diseases from exposure to 
respirable coal mine dust. These risks increase with increasing 
exposure concentration and duration, and with exposure to dust of 
higher ranked coal. The QRA and associated benefits for this rulemaking 
were based on the Attfield and Seixas (1995) study because, in addition 
to the advantages described above, it best represents the recent 
conditions experienced by miners in the U.S. The QRA, Significance of 
Risk discussion, and Benefits estimates follow in Sections VI, VII, and 
IV (a)(2), respectively. The international studies provide an important 
basis for comparison with the U.S. findings, and several of the recent 
international studies are described in detail here.
    Bourgkard, et al., (1998) conducted a 4-year study of a group of 
French coal miners who were employed in underground and surface mines. 
The investigators examined the prognostic role of cumulative dust 
exposure, smoking patterns, respiratory symptoms, lung CT scans, and 
lung function indices for chest x-ray worsening and evolution to simple 
CWP and PMF. Bourgkard, et al., (1998), through selection of a younger 
worker population (i.e., 35-48 years old at start of study), attempted 
to focus on the early stages of simple CWP. In essence, they hoped to 
identify those miners who needed to be relocated to less dusty 
workplaces or who needed to be clinically monitored. Bourgkard, et al. 
(1998) found a significant association between cumulative dust exposure 
and what was termed chest x-ray ``worsening'' (i.e., increase in 
reader-designated category signifying progression of simple CWP). In 
addition, they found that miners with pneumoconiosis, wheezing, 
decreased lung function, and high cumulative dust exposure at the first 
medical examination were those most likely to show worsening on their 
chest x-rays four years later.
    Love, et al. (1997, 1992) reported on occupational exposures and 
the health of British opencast (i.e., surface or strip) coal miners. 
They studied a group of approximately 1,200 miners who were employed at 
sites in England, Scotland, and Wales. The mean age of the men was 41; 
many had worked in the mining industry since the 1970s. To determine 
dust exposure levels, full-shift personal samples were collected. Most 
were respirable dust samples which were collected using Casella 
cyclones according to the procedures described by the British Health 
and Safety Executive (HSE). Thus exposure determinations would be 
comparable to exposure determinations obtained in U.S. surface coal 
mines since both measure respirable dust according to the British 
Medical Research Council (BMRC) criteria.
    These investigators found a doubling in the relative risk of 
developing profusion of simple CWP category 0/1 for every 10 years of 
work in the dustiest jobs in surface mines. These respirable coal dust 
exposures were under 1 mg/m\3\. Love, et al. (1992, 1997), like other 
investigators, emphasized the need for monitoring and controlling 
exposures to respirable coal mine dust, particularly in high risk 
operations (e.g., drillers, drivers of bulldozers).
    Meijers, et al. (1997) studied Dutch coal miners who were examined 
between 1952 and 1963, and who were followed until the end of 1991. 
They reported an increased risk of mortality from simple CWP and PMF 
among miners who had generally worked underground for 20 or more years. 
Their conclusions were based upon dramatic increases in standardized 
mortality ratios (SMRs). There were several limitations in this study, 
however.
    Morfeld, et al. (1997) published a recent paper that investigated 
the risk of developing simple CWP in German miners and addressed the 
occupational exposure limit for respirable coal dust in Germany. Their 
study included

[[Page 10844]]

approximately 5,800 miners who worked underground from the late 1970s 
to mid-1980s. Morfeld, et al. observed increases in relative risks 
(RRs) of developing early x-ray changes, category 0/1, that were 
exposure-dependent. Relative risks (RRs) increased with higher dust 
concentrations.
    Starzynski, et al. (1996) conducted a mortality study on a group of 
11,224 Polish males diagnosed with silicosis, simple CWP, or PMF 
between 1970 and 1985. This cohort was subdivided by occupation into 
four subcohorts: Coal miners (63%); employees of underground work 
enterprises (8%) (i.e.,drift cutting and shaft construction jobs); 
metallurgical industry and iron, and nonferrous foundry workers (16%); 
and refractory materials, china, ceramics and quarry workers (13%). The 
investigators found that coal miners had a slight, statistically 
significant excess overall mortality (i.e., all causes) as indicated by 
a standardized mortality ratio (SMR) of 105 (with a 95% confidence 
interval (C.I.) of 100-110). Also, excess of deaths from diseases of 
the respiratory system among coal miners was nearly four times that of 
the referent population (SMR of 383 with a 95% C.I. of 345-424). The 
study of Starzynski, et al. (1996) agrees with others that there is 
premature mortality among coal miners from simple CWP and PMF. 
Unfortunately, there is little or no information presented on miner 
work history, exposure assessment (e.g., respirable coal mine dust, 
silica), and mine environment (e.g., coal rank(s), underground vs. 
surface mining).
    Yi and Zhang (1996) conducted a study to measure the progression 
from simple CWP to PMF or death among a cohort of 2,738 miners with 
simple CWP who were employed at the Huai-Bei coal mine in China. 
Relative risks (i.e., RRs) were calculated for progression from simple 
CWP category 1 to simple CWP category 3 and for progression from simple 
CWP category 3 to death. Their results demonstrated that miners with 
simple CWP category 1 are at risk of developing simple CWP category 2 
and simple CWP category 3 (e.g., RRs of 1.101 and 2.360, respectively). 
They also found that miners with PMF had a decreased life expectancy. 
Other risk factors for development of PMF included long-term work 
underground, and drilling. This study was limited by a lack of exposure 
assessment, estimation of miner smoking histories, and use of a 
radiological classification system that differs from that of the ILO.
    Hurley and Maclaren (1987) studied British coal miners who were 
examined between 1953 and 1978, over 5-year intervals. They have shown 
that exposure to respirable coal dust increases the risks of developing 
simple CWP and of progressing to PMF. As seen in their data analysis, 
these responses were dependent upon dust concentration and coal rank. 
That is, greater responses were seen at higher dust concentrations and 
with higher rank coal (i.e., increasing percent carbon). The 
investigators also noted that estimated risks were unaffected by 
changes in the proportion of miners with simple CWP who transferred 
jobs. The authors concluded that ``limiting exposure to respirable coal 
dust is the only reliable way of limiting the risks of radiological 
changes to miners.''
b. Other Health Effects
    As noted in Table V-2, there were 21 studies in which the loss of 
lung function (LLF) was examined in coal miners. Fourteen of these 
studies also included an evaluation of respiratory symptoms (RS) in the 
miners. There were nine studies describing chronic obstructive 
pulmonary disease (COPD) in miners.
    Henneberger and Attfield (1997; 1996), Kuempel, et al. (1997), 
Seixas, et al. (1993), Attfield and Hodous (1992), and Seixas, et al. 
(1992) evaluated data from pulmonary function tests and standardized 
questionnaires to miners in the NSCWP. A common finding in their 
studies was an increase in respiratory symptoms such as cough, 
shortness of breath, and wheezing. The symptoms were dependent upon the 
dust concentration to which the miners had been exposed, with more 
pronounced symptoms occurring after long-term exposures to higher 
exposure levels. These studies also demonstrated that a loss of lung 
function occurred among miners.
    Attfield and Hodous (1992) studied U.S. miners who had spent 18 
years underground (on average) and who participated in Round 1 (1969-
1971) of the NSCWP. They observed that greater reductions in pulmonary 
function were associated with exposure to higher ranks of coal (i.e., 
anthracite vs. bituminous vs. lignite). Using linear regression models, 
Kuempel et al., (1997) predicted the excess (exposure attributable) 
prevalence of lung function decrements among miners with cumulative 
exposures to respirable coal mine dust of 2 mg/m\3\ for 45 years (i.e., 
90 mg-yr/m\3\). The excess prevalence estimated were 315 and 139 cases 
per thousand for forced expiratory volume in one second 
(FEV1) of <80% and <65% of predicted normal values, 
respectively, among never-smoking miners (a sub-group of 977 NSCWP 
participants studied in Seixas et al., 1993). Such reductions in 
FEV1 are clinically significant; FEV1 <80% (of 
predicted normal values) is a measure that is used to determine 
ventilatory defects (American Thoracic Society, 1991). Three recent 
studies found impaired FEV1 to be a predictor of increased 
pre-mature mortality (Weiss, et al., 1995; Meijers, et al., 1997; 
Hansen et al., 1999).
    Seixas, et al. (1993) conducted an analysis of 977 underground coal 
miners who began working in or after 1970 and were participants of both 
NSCWP Round 2 (1972-1975) and Round 4 (1985-1988). They found a rapid 
loss of lung function in miners and further declines in lung function 
with continuing exposure to coal mine dust. Collectively these studies 
have shown that the prevalence of decreased lung function was 
proportional to cumulative exposure. That is, with exposure to higher 
coal dust levels over a working lifetime, there were more miners who 
experienced a loss of lung function. Also, the types of respiratory 
symptoms and patterns of pulmonary function decrements observed by both 
Attfield and Hodous (1992) Seixas, et al. (1992;1993) are 
characteristic of COPD.
    The U.S. findings on respiratory symptoms and loss of lung function 
in miners have agreed with those of previous British studies by Marine, 
et al. (1988) and Soutar and Hurley (1986). Marine, et al. (1988) 
analyzed data from British coal miners and focused their attention on 
respiratory conditions other than simple CWP and PMF. In particular, 
they examined the Forced Expiratory Volume in one second 
(FEV1) among smoking and nonsmoking miners and, on the basis 
of reported respiratory symptoms, identified those miners with 
bronchitis. Using these data, logistic regression models were used to 
estimate the prevalence of chronic bronchitis and loss of lung 
function. Marine, et al. concluded that both exposure to respirable 
coal mine dust and smoking independently cause decrements in lung 
function; their contributions to COPD appeared to be additive in coal 
miners.
    Soutar and Hurley (1986) examined the relationship between dust 
exposure and lung function in British coal miners and ex-miners. The 
men who were studied were employed in coal mines in the 1950s and were 
followed up and examined 22 years later. These miners and ex-miners 
were categorized as smokers, ex-smokers, or nonsmokers. The Forced 
Expiratory Volume in one second (FEV1), the Forced Vital 
Capacity (FVC), and the FEV1/FVC ratios decreased in all 
study groups and these reductions in lung function were

[[Page 10845]]

inversely proportional to dust exposure. Thus, Soutar and Hurley 
concluded that exposure to respirable coal mine dust can cause severe 
respiratory impairment, even without the presence of simple CWP or PMF. 
They speculated that the pathology of coal dust-induced lung disease 
differs from that induced by smoking.
    Centrivacinar emphysema in coal miners has been associated with the 
amount of dust retained in their lungs at the end of life and with 
their dust exposures during life and the years worked underground 
(Ruckley et al., 1984; Leigh et al., 1983, 1994). Emphysema in coal 
miners has also been associated with pathological measurements of 
pneumoconiosis (Cockcroft et al., 1982a), and with lung function 
decrements and irregular opacities on chest x-rays (Cockcroft et al. 
1982b,c; Cockcroft and Andersson, 1987).
    Recent studies from China (Wang, et al., 1997) and the European 
community (Bourgkard, et al., 1998; Carta, et al., 1996; Lewis, S., et 
al., 1996) have also supported the British and U.S. findings which 
demonstrated the correlation between occupational exposure to coal dust 
and respiratory symptoms and loss of lung function in miners.
    Wang, et al. (1997) examined lung function in underground coal 
miners and other workers from several factories in Chongqing, China. 
For their study, information was obtained on exposure duration, results 
of radiographic tests, and smoking history. Pulmonary function tests 
were performed, providing the Forced Expiratory Volume in one second 
(FEV1), the Forced Vital Capacity (FVC), and 
FEV1/FVC data. Additionally, the diffusing capacity for 
carbon monoxide (DLCO) was measured. This is an indicator of 
diffusion impairment at the ``blood-gas barrier'' which may occur, for 
example, when this barrier becomes thickened (West, 1990; 1992). Wang, 
et al. (1997) found that there was impairment of pulmonary function 
among the coal miners and they had evidence of obstructive disease. 
Like other studies, such effects were observed among coal miners even 
in the absence of simple CWP. Pulmonary function was further decreased 
when simple CWP was present. This study did not provide exposure 
measurements and there was no consideration of exposure-response 
relationships. Also, silica exposures and their potential effects were 
not examined in the underground coal miners.
    As noted above, Bourgkard, et al. (1998) was interested in the 
earlier stages of simple CWP (i.e., Categories 0/1 and 1/0) and the 
prognostic role of cumulative dust exposure, smoking patterns, 
respiratory symptoms, lung CT scans, and lung function indices for 
chest x-ray worsening and evolution to simple CWP category 1/1 or 
higher. Over a 4-year period, they studied French coal miners who were 
employed in underground and surface mines. Bourgkard, et al. (1998) 
found that, at the first medical examination, the ratio of the Forced 
Expiratory Volume in one second (FEV1) to the Forced Vital 
Capacity (FVC) (i.e., FEV1/FVC) and other airflows 
determined from a forced expiration (West, 1990; 1992) were lower among 
miners who later developed simple CWP category 1/1 or higher. These 
miners also experienced more wheezing at the first medical examination. 
Thus, the results of their study suggested that lung function changes 
may serve as an early indicator of miners who are at increased risk of 
developing simple CWP and PMF and who should be monitored more closely.
    Carta, et al. (1996) have examined the role of dust exposure on the 
prevalence of respiratory symptoms and loss of lung function in a group 
of young Italian coal miners (i.e., mean age at hire 28.9 years, mean 
age at first survey 31.2 years). These miners worked underground and 
were exposed to lignite (i.e., low rank coal) which had a 5-7% sulfur 
content. They were followed for a period of 11 years, from 1983 and 
1993. Carta, et al. (1996) found few abnormalities on miner chest x-
rays taken throughout the 11-year study. However, there was an 
increased prevalence of respiratory symptoms and loss of lung function. 
This was particularly noteworthy since dust exposures were often below 
1.0 mg/m3; the cumulative dust exposure for the whole cohort 
was 6.7 mg-yr/m3 after the first survey. Thus, Carta, et al. 
(1996) demonstrated that miners experience respiratory effects of 
exposure to dust generated from a lower rank coal and at lower 
concentrations. They have recommended yearly measurements of lung 
function for miners.
    Lewis, et al. (1996) studied a group of British miners, many of 
whom entered the coal industry in the 1970s. Based upon chest x-rays, 
the miners had no evidence of simple CWP or PMF. The objective of this 
study was to determine whether coal mining (i.e., exposure to 
respirable coal mine dust) is an independent risk factor for impairment 
of lung function. Lewis, et al. (1996) found that there was a loss of 
lung function in miners (smokers and nonsmokers), particularly among 
miners who were under approximately 55 years of age. For miners who 
smoked, there was a greater loss of lung function than in nonsmoking 
miners with the same level of exposure to respirable coal mine dust. 
Above age 55, the loss of lung function was similar for miners and 
their controls, although all smokers continued to exhibit a greater 
loss of lung function than nonsmokers. Lewis, et al. (1996) concluded 
that the deficits in lung function may occur in the absence of simple 
CWP and PMF, and independent from the effects of smoking.
    There have been two recent mortality studies that have demonstrated 
a relationship between exposure to respirable coal mine dust and 
development of COPD. This association was reported by Kuempel, et al. 
(1995) in the U.S., and by Meijers, et al. (1997) in the Netherlands. 
These two groups of investigators have reported that occupationally-
induced COPD (e.g., chronic bronchitis, emphysema) can occur in miners, 
with or without the presence of simple CWP or PMF. They also found that 
the risk of premature mortality from COPD was elevated among miners and 
could be separated from the effects of smoking and age.
    Kuempel, et al. (1995) found an increase in relative risk (RR) of 
premature mortality from COPD among U.S. coal miners who participated 
in the NSCWP from 1969 through 1971. In their data analysis, the 
exposure-response relationship was evaluated using the Cox proportional 
hazards model. This model assumes that the hazard ratio between 
nonexposed and exposed groups does not significantly change with time. 
When fitting a curve to the data (e.g., log-linear), cumulative 
exposure was expressed as a categorical or continuous variable. Due to 
model limitations (e.g., less statistical power, influence of category 
scheme, use of lowest exposure group for comparisons vs. use of non-
exposed group), Kuempel, et al., (1995) believed that the exposure data 
should be expressed as a continuous variable. If, for example, the 
cumulative exposure was 90 mg-yr/m3 (i.e., 2 mg/
m3 for 45 years), then the relative risk of mortality from 
chronic bronchitis or emphysema was 7.67. Kuempel, et al. (1995) also 
showed that relative risk decreased with lower cumulative exposures 
(i.e., below 90 mg-yr/m3) and increased with higher 
cumulative exposures (i.e., above 90 mg-yr/m3). Thus, these 
investigators demonstrated a statistically significant exposure-
response relationship for COPD.
    Meijers, et al. (1997) have shown, among Dutch miners, reductions 
in lung volumes and capacities are good predictors of the increased 
risk of

[[Page 10846]]

premature mortality from COPD. For example, a diminished forced 
expiratory volume in one second (FEV1) or a diminished ratio 
of the FEV1 to the forced vital capacity \16\ (FVC) (i.e., 
FEV1/FVC) upon medical examination was associated with a 
significantly increased standardized mortality ratio (SMR) for COPD 
(322 and 212, respectively). In other words, miners with diminished 
lung capacity based on FEV1 were two to three times more 
likely to die prematurely due to COPD than miners who had normal lung 
function. In contrast, SMRs for COPD were not significantly increased 
in miners with normal lung volumes and capacities. These data support 
prior conclusions of Seixas, et al. (1992, 1993) and Attfield and 
Hodous (1992) based on morbidity studies.
---------------------------------------------------------------------------

    \16\ Forced vital capacity (FVC) is the total volume of gas that 
can be exhaled with a forced expiration after a full inspiration; 
The vital capacity measured with a FVC may be less than that 
measured with a slower exhalation (West, 1992).
---------------------------------------------------------------------------

VI. Quantitative Risk Assessment

    Having reviewed the reported health effects associated with 
exposure to respirable coal mine dust, MSHA has evaluated the evidence 
to determine whether the current regulatory strategy can be improved. 
The criteria for this evaluation are established by section 
101(a)(6)(A) (30 U.S.C. 811(a)(6)(A)) of the Mine Act, which states 
that:

    The Secretary, in promulgating mandatory standards dealing with 
toxic materials or harmful physical agents under this subsection, 
shall set standards which most adequately assure on the basis of the 
best available evidence that no miner will suffer material 
impairment of health or functional capacity even if such miner has 
regular exposure to the hazards dealt with by such standard for the 
period of his working life.

    Based on Court interpretations of similar language under the 
Occupational Safety and Health Act, there are three questions that must 
be addressed: (1) Whether health effects associated with the current 
pattern of overexposures on individual shifts constitute a material 
impairment to miner health or functional capacity; (2) whether the 
current pattern of overexposures on individual shifts places miners at 
a significant risk of incurring any of these material impairments; and 
(3) whether the proposed rules will substantially reduce those risks.
    The statutory criteria for evaluating the health effects evidence 
do not require absolute certainty. Under section 101(a)(6)(A) of the 
Mine Act, MSHA is required to proceed according to the ``best available 
evidence'' (30 U.S.C. 811(a)(6)(A)). Furthermore, the need to evaluate 
risk does not mean that an agency is placed into a ``mathematical 
straightjacket.'' In Industrial Union Department, AFL-CIO v. American 
Petroleum Institute (448 U.S.), otherwise known as the ``Benzene'' 
decision, the court ruled that:

    So long as they are supported by a body of reputable scientific 
thought, the Agency is free to use conservative assumptions in 
interpreting the data * * * risking error on the side of 
overprotection rather than underprotection. (448 U.S. 607, 100 S.Ct 
2844 (1980) at 656)

    As explained earlier, MSHA's objective in strengthening the 
requirements for verifying the effectiveness of dust control plans, and 
in enforcing effective plans through the new enforcement policy 
proposed, is to ensure that no miner is exposed to an excessive 
concentration of respirable dust on any individual shift (i.e., a 
concentration in excess of the applicable dust standard). MSHA's 
samples, combined with the more frequent bimonthly operator samples 
reveal recent overexposures on individual shifts in many mines. 
Furthermore, these dust samples demonstrate that, in many mines, dust 
concentrations exceed the applicable dust standard on a substantial 
percentage of the production shifts. This pattern has persisted for 
many years; and, since the existing program permits individual shift 
excursions above the applicable dust standard, a similar pattern can be 
expected to continue over the working lifetime of affected miners--
unless an effort is made to eliminate excessive exposures on individual 
shifts.
    In this quantitative risk assessment (QRA), MSHA will demonstrate 
that reducing respirable coal mine dust concentrations to no more than 
the applicable dust standard on each and every shift would, over a 45-
year occupational lifetime, significantly bring down the cumulative 
exposure to respirable coal mine dust, thereby significantly reducing 
the risk of both simple CWP and PMF among miners. This reduction in 
risk would result from reducing concentrations on just that percentage 
of shifts currently showing an excess.
    MSHA has estimated health benefits of the two rules based on 
eliminating excessive exposures at only those MMUs and roofbolter 
designated areas (RB-DAs) currently exhibiting a pattern of recurrent 
overexposures on individual shifts. In the previous proposed rule, MSHA 
used operator sampling data from the year 1999 to identify and 
characterize such MMUs. In the current proposed rule, MSHA has updated 
the analysis to 2001, included MSHA DO sampling data in addition to 
operator data, and expanded the quantitative analysis to include the 
reduction in risk expected for certain miners not previously considered 
(i.e., miners working in RB-DAs). As a result, MSHA believes it has now 
more comprehensively quantified the reduction in risk expected for the 
most highly exposed miners currently subject to recurrent 
overexposures.
    By ``exhibiting a pattern of recurrent overexposures,'' MSHA means 
that, for the same DO or RB-DA, at least two valid MSHA or bimonthly 
operator samples have exceeded the applicable dust standard during a 
year. MMUs exhibiting such a pattern are highly likely to have 
experienced excessive exposures on at least six shifts during the year 
under consideration.\17\
---------------------------------------------------------------------------

    \17\ MSHA estimates a MMU average of 384 production shifts per 
year. At MMUs exhibiting a pattern of recurrent overexposures in 
2001, valid DO samples were obtained on an average of about 30 of 
these 384 production shifts. If dust concentrations on two or more 
of the sampled shifts exceed the standard, then it follows, at a 95-
percent confidence level, that the standard is exceeded on at least 
six shifts over the full year.
    If a different definition of ``exhibiting a recurrent pattern of 
overexposures'' had been used in the QRA, the estimate of the 
reduction in risk and associated benefits would have been different. 
For example, if the criterion were that four or more bimonthly DO 
exposure measurements exceeded the applicable dust standard then 
overexposures would be expected, with 95% confidence, to occur on at 
least 20 shifts in a year of 384 shifts. Using more than two 
recorded overexposures as the criterion would arbitrarily reduce the 
population for which MSHA is estimating benefits and decrease the 
estimated number of prevented cases.
---------------------------------------------------------------------------

    Based on 2001 MSHA and operator data, there were 716 MMUs (out of 
1,256 total) at which dust concentrations for the DO exceeded the 
applicable dust standard on at least two of the sampling shifts (MSHA, 
datafile: DO--2001.ZIP). MSHA considers these 716 MMUs, representing 57 
percent of all MMUs and more than one-half of all underground coal 
miners working in production areas, to have exhibited a pattern of 
recurrent overexposures. Valid DO samples were collected on a total of 
20,905 shifts at these 716 MMUs, and the applicable dust standard was 
exceeded on 4,028 of these shifts, or 19.3 percent. For this 19.3 
percent, the mean excess above the standard, as measured for the DO 
only, was 1.04 mg/m3.
    These results are based on a large number of shifts (an average of 
nearly 30 at each of the 716 MMUs). Therefore, assuming representative 
operating conditions on these shifts, the results can be extrapolated 
to all production

[[Page 10847]]

shifts, including those that were not sampled, at these same 716 MMUs. 
With 99-percent confidence, the overall percentage of production shifts 
on which the DO sample exceeded the standard was between 18.6 percent 
and 20.0 percent for 2001. At the same confidence level, again assuming 
representative operating conditions, the overall mean excess on 
noncompliant shifts at these MMUs was between 0.96 mg/m3 and 
1.11 mg/m3. If, as some commenters on the earlier single 
sample proposed rule and the Dust Advisory Committee proceedings have 
alleged, operators tend to reduce production and/or increase dust 
controls on sampled shifts, then the true values could be higher than 
even the upper endpoints of these 99-percent confidence intervals.
    The available data suggest that, unless changes are made to enforce 
the applicable dust standard on every shift, the same general pattern 
of overexposures observed in 2001 will persist into the future.\18\ 
Therefore, MSHA concludes that without the proposed changes:
---------------------------------------------------------------------------

    \18\ Appendix VI.1 compares the pattern observed in 2001 to that 
in earlier years.
---------------------------------------------------------------------------

    [sbull] More than half of all MMUs would continue to have a pattern 
of recurrent overexposures on individual shifts;
    [sbull] At those MMUs with recurrent overexposures, full-shift 
average respirable dust concentrations for the DO would continue to 
exceed the applicable dust standards on about 20 percent of all 
production shifts;
    [sbull] Among those shifts on which DO exposure exceeds the 
applicable dust standards, the mean excess for the DO would continue to 
be approximately 1 mg/m\3\.
    If all overexposures on individual shifts are eliminated, the 
reduction in total respirable coal mine dust inhaled by a miner over a 
working lifetime will depend on three factors: (1) The average volume 
of air inhaled on each shift that would otherwise have exceeded the 
applicable dust standard, (2) the degree of reduction in respirable 
dust concentration in the air inhaled on such shifts, and (3) the 
number of such shifts per working lifetime. While the inhaled dose (mg) 
could not be measured directly, it is biologically and quantitatively 
related to the accumulated exposure (i.e., airborne concentration 
multiplied by duration, summed across jobs for each miner) used to 
predict CWP and PMF prevalences in the Attfield-Seixas models. If a 
miner inhales ten cubic meters of air on a shift (U.S. EPA, 1980), 
reducing the respirable coal mine dust concentration in that air by 
1.04 mg/m\3\ will result in 10.4 mg less dust inhaled on that shift 
alone. Assuming the miner works 240 shifts per year, then reducing 
inhaled respirable dust by an average of 10.4 mg on 19.3 percent of the 
shifts will reduce the total respirable coal mine dust inhaled by 482 
mg per year, or nearly 22,000 mg over a 45-year working lifetime:

1.04 mg less respirable coal mine dust per m\3\ of inhaled air
    x 10 m\3\ inhaled air per shift
    x 46.32 affected shifts (i.e., 19.3% of 240) per work year
    x 45 work years per working lifetime
    = 21,678 mg less respirable coal mine dust inhaled per working 
lifetime.

    In Section V, the strengths and weaknesses of various 
epidemiological studies were presented, supporting the selection of 
Attfield and Seixas (1995) as the study that provides the best 
available estimate of material health impairment with respect to CWP. 
Two strengths of this study are its quantitative description of 
exposure-response among both miners and ex-miners (who had worked as 
miners for approximately 13-40 years) and the fact that it reflects 
recent conditions experienced by coal miners in the U.S. Using the 
exposure-response relationship it is possible to estimate the health 
impact of bringing dust concentrations down to or below the applicable 
dust standard on every shift. This is the only contemporary 
epidemiological study of CWP in U.S. miners providing such a 
relationship.
    Attfield and Seixas (op cit) used two or three B readers to 
identify the profusion of opacities based on the ILO classification 
scheme.\19\ The most inclusive category defined in their paper was CWP 
1+, which include simple CWP categories 1, 2, and 3, as well as PMF. 
The second category CWP 2+, does not include simple CWP, category 1, 
but does include the more severe simple CWP categories, 2 and 3, as 
well as PMF. The third category used in their report was PMF, denoting 
any category (A, B, or C) of large opacities. The authors applied 
logistic regression models to the prevalence of CWP 1+, CWP 2+, and PMF 
as a function of accumulated coal mine dust exposure calculated for 
each miner included in the study. In the absence of data 
differentiating the inhalation rates of individual miners, the 
accumulated exposures in these models were expressed in units of mg-yr/
m \3\.
---------------------------------------------------------------------------

    \19\ If three readings were available, the median value was 
used. If two readings were available, the higher of the two ILO 
categories was recorded. Eighty radiographs were eliminated because 
only one reading was available.
---------------------------------------------------------------------------

    At the MMUs being considered (those exhibiting a pattern of 
recurrent overexposures), bringing dust concentrations down to no more 
than the applicable dust standard on each and every production shift 
would reduce DO exposures on the affected shifts by an average of 1.04 
mg/m\3\. Assuming this average reduction applies to only 19.3 percent 
of the shifts, the effect would be to reduce cumulative exposure, for 
each miner exposed at or above the DO level, by 0.20 mg-yr/m\3\ over 
the course of a working year (i.e., 19.3 percent of shifts in one year, 
times 1.04 mg/m\3\ per shift). Therefore, over a 45-year working 
lifetime, the benefit to each affected miner would, on average, amount 
to a reduction in accumulated exposure of approximately 9.0 mg-yr/m\3\ 
(i.e., 45 years times 0.20 mg-yr/m\3\ per year). If, as some miners 
have testified, operator dust samples submitted to MSHA tend to under-
represent the frequency or magnitude (or both) of individual full-shift 
excursions above the applicable dust standard, then eliminating such 
excursions would provide a lifetime reduction of even greater than 9.0 
mg-yr/m\3\ for each affected miner.
    The Attfield-Seixas models predict the prevalence of CWP 1+, CWP 
2+, and PMF for miners who have accumulated a given amount of exposure, 
expressed in units of mg-yr/m\3\, by the time they attain a specified 
age. Benefits of reducing cumulative exposure can be estimated by 
calculating the difference between predictions with and without the 
reduction. For example, suppose a miner at one of the MMUs under 
consideration begins work at age 20 and retires at age 65. At these 
MMUs, the mean DO concentration reported in 2001 was 1.15 mg/m\3\; so, 
after 45 years, a miner exposed at this level can be expected to have 
accumulated a total exposure of nearly 52 mg-yr/m\3\ (i.e., 45 yr x 
1.15 mg/m\3\). By the year of retirement, such a miner is expected to 
accumulate, on average, 9.0 mg-yr/m\3\ less exposure if individual 
shift excursions are eliminated. For 65-year-old miners, reducing an 
accumulated total dust exposure of 52 mg-yr/m\3\ by 9.0 mg-yr/m\3\ 
reduces the predicted prevalence of ``CWP 1+'' by more than 16 per 
thousand (see the entry for affected DO miners in Table VI-1).\20\
---------------------------------------------------------------------------

    \20\ The Attfield-Seixas model predicts a higher prevalence of 
CWP, and consequently a greater risk reduction (35 per thousand DO 
miners at age 65), after 45 years of occupational exposure to coal 
mine dust in central Pennsylvania or southeastern West Virginia. 
(Attfield and Seixas attribute this effect to the type of coal mined 
in those geographic areas). However, few underground coal mines in 
central Pennsylvania or southeastern West Virginia are still 
operating. In fact, only about 29 of the 716 MMUs exhibiting a 
pattern of recurrent overexposures in 2001 were from those areas. 
Therefore, the risk assessment presented here, along with projected 
benefits of the rule, are based on the lower risks predicted for 
miners working outside central Pennsylvania and southeastern West 
Virginia.

---------------------------------------------------------------------------

[[Page 10848]]

    This result, however, applies only to DO miners at age 65. The 
Attfield-Seixas models provide different predictions for each year of 
age that a miner attains. The predicted benefit turns out to be smaller 
for younger miners and larger for older miners. This is partly because 
younger miners will have accumulated less exposure reduction as a 
result of today's final changes, and partly because the Attfield-Seixas 
models depend directly on age as well as on cumulative exposure. The 
health effects of recurrent overexposures can occur long after the 
overexposures occurred. Even after a miner retires and is no longer 
exposed to respirable coal mine dust, the additional risk attributable 
to an extra 9.0 mg-year/m\3\, accumulated earlier, continues to 
increase with age. Consequently, the benefit to be gained from 
eliminating individual shift excursions also continues to increase 
after a miner is no longer exposed. For example, assuming no additional 
exposure after age 65, the predicted reduction in average prevalence of 
CWP 1+ increases from 16.6 per thousand at age 65 to 21.4 per thousand 
at age 70. Presumably, the increasingly greater predicted reduction in 
risk of disease after age 65 is due to the latent effects of the 
reduction in earlier exposure and the progressive nature of CWP.
    To quantify benefits expected from eliminating overexposures on 
each and every shift, MSHA applied the Attfield-Seixas models to a 
hypothetical population of miners who, on average, begin working at age 
20 and retire at age 65, assuming different lifetimes.\21\ To show the 
range of potential reductions in risk depending on a miner's lifetime, 
Table VI-1 presents the risk reductions predicted at three different 
attained ages: 65, 73, and 80 years. The projected benefit increases 
with attained age. However, MSHA's best estimate of the benefit to 
exposed miners is expressed by the reduction in prevalence of disease 
predicted at age 73.\22\
---------------------------------------------------------------------------

    \21\ Appendix VI.2 contains a technical description of the 
Attfield-Seixas models and an explanation of how MSHA applied them 
to obtain the results shown in Table VI-1. The method used in 
applying the models differs slightly from that used in the previous 
proposed rule, and Appendix VI.2 also explains this difference. In 
addition, an EXCEL workbook entitled ``RiskRdxn.xlw'' showing the 
formulas used in the calculations has been placed into the public 
record for these proceedings.
    \22\ The expected lifetime for all American males, conditional 
on their having reached 20 years of age, is 73 years (calculated 
from U.S. Census, March 1997, Tables 18 and 119).
---------------------------------------------------------------------------

    Since not all underground coal miners are overexposed to dust with 
the same frequency or at the same level, Table VI-1 shows the risk 
reductions projected for three different categories of affected miners: 
(1) DO miners, (2) NDO miners who are faceworkers neither classified as 
a DO nor subject to a separate applicable dust standard applicable to a 
RB-DA, and (3) DA roofbolters. The reduction in risk predicted for each 
of these three categories will now be discussed in turn.
    (1) DO Miners. As explained earlier, for DO miners the predicted 
lifetime exposure reduction accumulates at a rate of 0.20 mg/m\3\ of 
reduced exposure per year during the 45 ``working years'' between 20 
and 65, reaching a maximum of 9.0 mg-yr/m\3\ upon retirement at age 65. 
Between ages 65 and 80, the accumulated reduction in dust exposure 
remains at an estimated average of 9.0 mg-yr/m\3\, but (as also 
explained previously) the benefit in terms of both simple CWP and PMF 
risk continues to increase.
    The first row of Table VI-1 presents the reductions in risk 
expected among affected DO miners who work at a MMU exhibiting a 
pattern of recurrent overexposures. For this group of miners, the 
calculation at an average lifetime of 73 years shows that bringing dust 
concentrations down to no more than the applicable dust standard on 
each shift would:
    [sbull] Reduce the combined risk of simple CWP and PMF by 24.4 
cases per 1000 affected DO miners; \23\
---------------------------------------------------------------------------

    \23\ ``Affected DO miners'' include all miners who work at MMUs 
with a pattern of recurrent overexposures and who are exposed to 
dust concentrations similar to the DO over a 45-year working 
lifetime.
---------------------------------------------------------------------------

    [sbull] Reduce the combined risk of simple CWP (category 2 and 3) 
and PMF by 15.5 cases per 1000 affected DO miners;
    [sbull] Reduce the risk of PMF by 7.6 cases per 1000 affected DO 
miners.
    When the dust concentration measured for the DO exceeds the 
applicable dust standard, measurements for at least some of the other 
miners in the same MMU may also exceed the standard on the same shift, 
though usually by a lesser amount. Furthermore, although the DO 
represents the occupation most likely to receive the highest exposure, 
one or more of these other miners may be exposed to even higher 
concentrations than the DO on some shifts. Therefore, the second 
category of affected miners addressed in Table VI-1 is the population 
of non-DO faceworkers other than those working in roofbolter DAs (who 
are addressed as a separate, third category).
    (2) NDO Miners. This category covers all faceworkers other than the 
DO, except those roofbolters for which a separate DA applicable dust 
standard has been established. (Roofbolters not coming under a DA 
standard are included in the NDO category). To estimate how NDO miners 
(other than those subject to a DA standard) would be affected by the 
proposed rules, MSHA examined the results from all valid dust samples 
collected by MSHA in underground MMUs during 2001 (MSHA, data file: 
Insp2001.zip). Within each MMU, MSHA typically takes one sample on the 
DO and, on the same shift, four or more additional samples representing 
other occupations. In 2001, there was an average of 1.0 NDO measurement 
in excess of the standard on shifts for which the DO measurement 
exceeded the standard.\24\ For NDO measurements that exceeded the 
standard on the same shift as a DO measurement, the mean excess above 
the standard was approximately 0.6 mg/m\3\.\25\
---------------------------------------------------------------------------

    \24\ With 95-percent confidence, on shifts for which the DO 
measurement exceeds the standard, the mean number of other 
occupational measurements also exceeding the standard is at least 
0.91.
    \25\ With 95-percent confidence, the mean excess is at least 
0.59 mg/m\3\.
---------------------------------------------------------------------------

    Combining these results with the 19.3 percent rate of excessive 
exposures observed for the DO on individual shifts, it is reasonable to 
infer that, at the MMUs under consideration, an average of 1 other 
miner, in addition to the 1 classified as DO, is currently overexposed 
on at least 19 percent of all production shifts. In 2001, the mean of 
the highest dust concentration reported for any non-DO miner on sampled 
shifts was 1.08 mg/m\3\. Over the course of each working year, the 
reduction in exposure expected for such miners as a result of 
implementing the proposed rules is 0.12 mg-yr/m\3\ (i.e., 19.3 percent 
of one year, times 0.6 mg/m\3\).
    To assess the reduction in risk expected from eliminating all 
single-shift exposures for these NDO miners, MSHA again applied the 
Attfield and Seixas models to miners who begin working at age 20 and 
retire at age 65, assuming lifetimes of 65, 73, and 80 years. This 
time, however, the resulting decrease in predicted prevalence was 
multiplied by 1.0/6 = 0.167, to reflect the fact that the assumed rate 
of overexposure applies, on average, to

[[Page 10849]]

about one-sixth of the faceworkers not classified as the DO.\26\
---------------------------------------------------------------------------

    \26\ There are an estimated 6 NDO miners for each DO miner, and 
an average of 1.0 of these 6 miners is overexposed. This does not 
include roofbolters working in designated areas, who are treated as 
a separate group in the present analysis.
---------------------------------------------------------------------------

    The second row of Table VI-1 contains the risk reductions for NDO 
miners expected as a result of eliminating all individual shift 
overexposures. Over an occupational lifetime, the average reduction in 
risk for simple CWP and PMF combined, and for PMF alone, increases with 
age. However, the risk reduction at each age is smaller for the 
affected NDOs than for the affected DOs. This is expected because the 
estimated probability that a NDO (other than a RB-DA) will, under 
current conditions, be overexposed on a given shift is only 16.7 
percent of the corresponding probability for the DO. For the MMUs under 
consideration, the predicted reduction in risk for faceworkers other 
than the DO who live an expected lifetime of 73 years is: 2.3 fewer 
cases of ``CWP 1+'' per thousand affected NDO miners; 1.5 fewer cases 
of ``CWP 2+'' per thousand affected NDO miners; and 0.7 fewer cases of 
PMF per thousand affected NDO miners.
    (3) Roofbolter DA (RB-DA) Miners. Because roofbolters are often 
exposed to higher quartz concentrations than other miners, the 
applicable dust standard for them is frequently different from the 
standard applicable to other miners working in the same MMU. Therefore, 
many roofbolters are classified as working in a ``roofbolter designated 
area'' (RB-DA). For purposes of this QRA, such roofbolters were 
excluded from the analysis of NDO miners presented above. Based on 2001 
MSHA and operator data, 194 out of a total 659 RB-DAs met MSHA's 
criterion for exhibiting a pattern of recurrent overexposures--i.e., 
dust concentrations exceeded the applicable dust standard on at least 
two of the sampled shifts (MSHA, datafile: RBDA2001.ZIP). Valid RB-DA 
samples were collected on a total of 3477 shifts at these 194 RB-DA 
MMUs, and the applicable dust standard was exceeded on 837 of these 
shifts, or 24.1 percent (95% confidence interval: 22.7 to 25.5). For 
this 24.1 percent, the mean excess above the standard, as measured for 
the RB-DA only, was 0.72 mg/m\3\ (95-percent confidence interval: 0.64 
to 0.80).
    At these RB-DAs (i.e., those exhibiting a pattern of recurrent 
overexposures), the mean concentration reported in 2001 was 0.94 mg/
m\3\; so, after 45 years, an RB-DA miner can be expected, if there is 
no change in current conditions, to have accumulated a total exposure 
of more than 42 mg-yr/m\3\. By retirement at age 65, such a miner would 
be expected to accumulate, on average, 7.8 mg-yr/m\3\ less exposure if 
overexposures on all individual shifts were eliminated. (45 years x 
24.1% of 0.72 mg/m\3\). The third row of Table VI-1 shows the estimated 
impact of the proposed rules on the risk predicted for RB-DA 
roofbolters. At age 73, reducing an accumulated total dust exposure of 
42 mg-yr/m\3\ by 7.8 mg-yr/m\3\ reduces the predicted prevalence of 
``CWP 1+'' by 19.6 per thousand, of ``CWP 2+'' by 12.1 per thousand, 
and of PMF by 6.0 per thousand.

  Table VI-1.--By Age, Average Reduction in Cases of Occupational Respiratory Disease Expected To Result From Implementation of Single Sample and Plan
                                                                   Verification Rules
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                           Reduction in cases of occupational respiratory disease per 1,000 affected miners
                                             -----------------------------------------------------------------------------------------------------------
                                              Simple CWP \a\ (categories 1, 2 or   Simple CWP(categories 2 or 3) or                   PMF
                                                  3) or PMF \b\ (``CWP 1+'')               PMF (``CWP 2+'')          -----------------------------------
                Type of miner                ------------------------------------------------------------------------                 Age
                                                              Age                                 Age                -----------------------------------
                                             ------------------------------------------------------------------------
                                                  65          73          80          65          73          80          65          73          80
--------------------------------------------------------------------------------------------------------------------------------------------------------
Affected Designated Occupation Miners \c\           16.6        24.4        30.6         6.3        15.5        28.0         2.8         7.6        16.1
 (DO).......................................
Affected Non-Designated Occupation Miners            1.6         2.3         2.9         0.6         1.5         2.7         0.3         0.7         1.5
 \d\ (NDO)..................................
Affected Roof Bolter Designated Areas Miners        13.0        19.6        25.3         4.8        12.1        22.5         2.2         6.0       12.8
 \e\ (RB-DA)................................
--------------------------------------------------------------------------------------------------------------------------------------------------------
\a\ Simple CWP: simple coal workers' pneumoconiosis.
\b\ PMF: progressive massive fibrosis.
\c\ Affected Designated Occupation (DO) Miners: includes all miners who work at the 57 percent of the Mechanized Mining Units under consideration and
  who are exposed to dust concentrations similar to the DO, over a 45-year occupational lifetime. Risk reduction estimates are based on reducing the
  mean dust concentration of 1.15 mg/m \3\ (Std. Error = 0.018) observed in 2001 for DOs at the MMUs under consideration.
\d\ Affected Non-Designated Occupation (NDO) Miners: includes all underground faceworkers under consideration who are not classified as the DO or a
  ``designated area roofbolter.'' Risk reduction estimates are based on reducing the mean dust concentration of 1.08 mg/m \3\ (Std. Error = 0.011)
  observed in 2001 for the NDO sample showing the highest dust concentration on a given MSHA sampling day within a MMU.
\e\ Affected Roofbolter Designated Area (RB-DA) Miners: includes all miners working as roofbolters in the 29.4 percent of RB-DAs exhibiting a pattern of
  recurrent overexposures. Risk reduction estimates are based on reducing the mean dust concentration of 0.94 mg/m \3\ (Std. Error = 0.025) observed in
  2001 for the RB-DAs under consideration.

    MSHA acknowledges that the assumptions and data used in this QRA 
are subject to various caveats, but the Secretary believes that, on 
balance, MSHA's analysis probably underestimates the increased risk of 
material impairment attributable to individual shift overexposures 
accumulated over an occupational lifetime. Some previous commenters, 
however, have disagreed with this assessment or argued that some 
aspects of it ``need further consideration.'' The only commenter 
offering specific criticisms was the NMA, which submitted a critique by 
M.J Nicolich and J.F. Gamble (September, 2000) along with general 
comments from Richard Lawson. Nicolich and Gamble brought up four 
points that, in the NMA's view, cast doubt on our conclusions. These 
four points will be discussed in turn.
    (1) According to Nicolich and Gamble, ``[t]he QRA has made some

[[Page 10850]]

assumptions that have led to incorrect estimates of the percent of 
miners who would be at reduced risk on the new plan, and have 
misrepresented the degree of risk reduction among the miners who would 
have reduced risk.'' In support of this position, Nicolich and Gamble 
argued that (a) the sample data on which the QRA was based were not 
independent and (b) that the distribution of values by which 
concentrations exceeded the applicable dust standard was likely to be 
skewed and would, therefore, be better represented by its median than 
by its mean. They argued, further, that as a consequence of (a), the 
estimated ``number of workers that will have reduced risk will likely 
be too high and the degree of risk among these fewer workers will be 
under-estimated * * *'' and that, as a consequence of (b), ``the degree 
of risk reduction among the miners experiencing over-exposure will 
likely be too large (because of an overestimate of the intensity of the 
exposure of the over-exposed miners).''
    Both parts of this argument are flawed. The discussion that 
Nicolich and Gamble offer in support of (a) has nothing to do with 
independence of sample data and provides no basis for concluding that 
MSHA has overestimated the percentage of miners expected to experience 
reduced risk if overexposures on individual shift are eliminated. It 
should also be noted that this part of their argument involves an 
apparent misunderstanding of how MSHA estimated the number of miners 
that would be affected by this rule. Contrary to Nicolich and Gamble's 
line of reasoning, the estimated percentage of shifts exceeding the 
applicable dust standard at MMUs exhibiting a pattern of recurrent 
overexposures was not used to estimate the size of the mining 
population at risk. It is true that the number of affected miners used 
in calculating benefits was estimated from the proportion of MMUs 
exhibiting a pattern of recurrent overexposures (see section IX.A.2. 
Benefits). However, this estimate would remain the same, regardless of 
the overexposure rate observed for MMUs defined as exhibiting a 
pattern. It is also true that if a more stringent criterion were used 
to define MMUs exhibiting a pattern, then fewer MMUs (and, therefore, 
fewer miners) would be included in the benefit estimates. The rule, 
however, applies to all MMUs, not just those defined as exhibiting a 
pattern of recurrent overexposures for purposes of the QRA. Therefore, 
adopting a more stringent criterion for recurrence would simply mean 
that additional miners benefitting from the rule would be left out of 
the benefit estimates.
    Furthermore, the second part of their argument (b) is not relevant 
to the calculation of the accumulated effect of individual shift 
exposures, as modeled by the Attfield/Seixas model being employed. In 
support of their position, Nicolich and Gamble present the example of 
nine laborers who earn $10,000 per year and a boss who earns $100,000 
per year and point out that the mean income ``is not a good measure of 
the `typical value.' '' They then propose (based on no supporting data 
other than that of this example) that the median would be a better 
measure of the ``typical'' degree by which individual shift 
overexposures exceed the applicable dust standard.
    Nicolich and Gamble fail to consider that the objective is not to 
estimate a ``typical'' degree of excess but, rather, to estimate the 
total degree of excess, accumulated over an occupational lifetime. The 
variable used in the Attfield/Seixas model is cumulative exposure, 
defined by the product of exposure duration and mean ``intensity'' 
(i.e., dust concentration), not median intensity. In the example of 
nine laborers and a boss, the total annual payout is ten times mean 
salary, not median salary. Similarly, cumulative exposure is given by 
the product of exposure duration and mean intensity regardless of the 
shape of the statistical distribution of excess dust concentrations. 
Since MSHA's use of the mean value fully accords with the Attfield/
Seixas model employed, the commenters have provided no basis for 
concluding that MSHA has overestimated the degree of risk reduction to 
be expected among miners experiencing individual shift overexposures.
    (2) According to Nicolich and Gamble, ``[t]he Attfield and Seixas 
model does not take into account the over-exposures identified by 
MSHA.'' Based on this premise, they argue that ``the estimates of 
exposure in the model are less than actual exposure and the E-R [i.e., 
exposure-response] slope is steeper than the actual slope.'' More 
specifically, they attempt to show that Attfield and Seixas should have 
estimated the mean concentration for face occupations to be 1.57 mg/m 
\3\ rather than 1.46 mg/m \3\. From this, they conclude that ``[t]he 
toxicity of coal mine dust is therefore over-estimated.''
    This argument is based on the false premise that individual shift 
overexposures were not included in the data from which the Atffield/
Seixas model was generated. Contrary to Nicolich and Gamble, however, 
neither MMUs with a pattern of recurrent overexposures nor individual 
shift overexposures per se were excluded from the data used by Attfield 
and Seixas. Therefore, contrary to their argument, the existence of 
such overexposures does not create a ``bias in exposure estimates'' 
that ``produces an overestimate in the toxicity of coal mine dust.'' 
Specifically, the value of 1.46 mg/m\3\ used by Attfield and Seixas to 
represent the mean concentration for faceworkers already includes those 
measurements exceeding the applicable dust standard. Therefore, the 
corresponding value (1.57 mg/m\3\) proposed by Nicolich and Gamble 
essentially double-counts those measurements.
    (3) According to Nicolich and Gamble, ``[t]here is a background 
prevalence of CWP that is not related to coal mine dust exposure'' and 
``prevalences that occur at zero exposure should be subtracted from the 
observed prevalence.'' Nicolich and Gamble failed to note that 
background prevalences have no bearing on the expected reductions in 
risk as calculated and presented in this risk assessment. All estimates 
of expected risk reduction in this QRA are based on calculating a 
difference between two estimated risks: with and without the 
elimination of individual shift overexposures accumulated over an 
occupational lifetime. Both of these estimated risks include the same 
background effect that is not attributable to coal mine dust exposure. 
Therefore, any background effect is canceled out when the difference is 
calculated. The estimated reduction in risk is, according to the 
Attfield/Seixas model, free of any background effect.\27\
---------------------------------------------------------------------------

    \27\ Although it is canceled by subtraction when estimating the 
effect of reducing cumulative exposure, the Attfield/Seixas model 
does, in fact, incorporate an age-dependent background effect. 
Therefore, since the model allows for a positive response at zero 
exposure, the slope of the exposure-response relationship is not 
artificially inflated.
---------------------------------------------------------------------------

    (4) Nicolich and Gamble criticized the use of irregular opacities 
as indicating coal workers' pneumoconiosis. However, studies have shown 
that the prevalences of both small rounded and small irregular 
opacities increase with increasing years worked underground (Amandus et 
al., 1976; Cockcroft et al., 1983) and with increasing coal mine dust 
exposure (Collins et al., 1988). The relationship between irregular 
opacities and coal mine dust exposure has been observed among both 
smokers and nonsmokers (Cockcroft et al., 1983). Amandus et al. (1976) 
found that smoking, age, and years underground

[[Page 10851]]

were all significant predictors of irregular opacities. Irregular 
opacities were most common among miners who were older than 30, had 
bronchitis, and smoked, but exposure to coal mine dust was still a 
significant factor. Collins et al. (1988) found that the small 
irregular opacities were statistically significantly associated with 
both dust exposure and age in U.K. coal miners, but did not find a 
significant relationship with smoking. The exposure-response 
relationship was less steep for small irregular opacities than for 
small rounded opacities (Collins et al, 1988). Therefore, the use of 
combined opacities rather than rounded opacities only may actually 
dampen the exposure-response relationship for pneumoconiosis (e.g., in 
Attfield and Seixas, 1995), which is in contrast to the Nicolich and 
Gamble comment that the inclusion of irregular opacities would over-
estimate the risk of pneumoconiosis. Nonetheless, the use of combined 
opacities is supported by the fact that statistically significant 
exposure-response relationships have been observed for both types of 
small opacities (rounded and irregular) in coal miners, and both types 
have been associated with adverse health effects.
    Miners with small rounded opacities on their chest x-rays were more 
likely to report symptoms of chronic bronchitis (cough and phlegm) than 
were miners without small opacities (category 0/0) (Rae et al., 1971). 
In Collins et al. (1988), both small rounded and small irregular 
opacities were associated with symptoms of chronic cough and phlegm, 
and breathlessness, compared to miners with no opacities observable on 
chest x-ray. Small irregular opacities have been associated with 
impaired lung function (Amandus et al., 1976; Cockcroft et al., 
1982b,c; Collins et al., 1988). As Nicolich and Gamble state in their 
comments, the lung function impairment reported by Collins et al. 
(1988) was in addition to that attributable to dust exposure. However, 
Collins et al. (1988) found that the observed pattern of lung function 
abnormalities was distinctly different from the pattern observed among 
smokers. Specifically, the mean FEV1 and mean FVC were significantly 
lower among miners with small irregular opacities compared to those 
with no observable opacities (i.e., chest x-ray category 0/0), and this 
is the pattern of lung function abnormality typically associated with 
dust exposure in coal miners (Collins et al., 1988). In contrast, 
smokers generally had more severe reductions in FEV1 than in FVC 
(resulting in a reduction in the FEV1/FVC ratio). The authors suggest 
that the irregular opacities in coal miners may represent damage to the 
lungs that causes airways obstruction at different lung locations than 
that caused by cigarette smoke. Irregular opacities in coal miners may 
have also been associated with emphysema (Cockcroft et al., 1982 b, c).
    Because simple CWP represents an early stage of a progressive 
disease, miners who have had a chest x-ray classified as ILO category 1 
or greater are more likely than those with a clear x-ray (category 0) 
to progress to the more severe stages of the disease, including the 
complicated form, PMF (categories A, B, or C) (Cochrane 1962; McLintock 
et al. 1971; Hurley et al. 1987; Morfeld et al., 1992). PMF has been 
associated with impaired lung function, disability, and early death 
(Rasmussen et al., 1968; Parkes et al., 1983; Miller and Jacobsen, 
1985), and miners with PMF qualify as totally disabled due to 
pneumoconiosis under the Department of Labor's Standards for 
Determining Coal Miners' Total Disability or Death Due to 
Pneumoconiosis under the criteria set forth at (20 CFR 718.304(a)). 
Miners with simple CWP were also found to have an increased risk of 
dying from pneumoconiosis (as the underlying or a contributing cause on 
the death certificate), and this risk tended to increase with 
increasing radiographic category (Kuempel et al., 1995). Nicolich and 
Gamble are incorrect in stating that an implication of that study is 
``no increased mortality associated with exposure''. Instead, Kuempel 
et al. (1995) showed a statistically significant exposure-response 
relationship for cumulative exposure to respirable coal mine dust and 
pneumoconiosis mortality.
    After due consideration of the questions posed by Nicolich and 
Gamble, we have concluded that the development of CWP, as detected on 
chest x-ray as rounded and/or irregular opacities, poses a significant 
health risk to miners. Miners who have developed simple CWP have a 
materially altered risk status, which is a medically and scientifically 
reasonable measure of material impairment. Miners who have a chest x-
ray with small opacities (rounded and/or irregular) are also more 
likely to report respiratory symptoms and/or to have lung function 
decrements. The use of radiographic evidence of pneumoconiosis 
(combined opacities), both by Attfield and Seixas (1995) and in MSHA's 
risk assessment, is appropriate for assessing the risk that coal miners 
will suffer material impairment of health or functional capacity as a 
result of their respirable dust exposures accumulated over a working 
lifetime.

Appendix VI.1 DO Overexposure Patterns

    In 1998, MSHA attempted to enforce compliance on individual shifts. 
Therefore, to compare the 2001 pattern of excess exposures on 
individual shifts to that of previous years, MSHA examined the regular 
bimonthly DO sample data submitted by mine operators in the 10 years 
from 1990 through 1997 and 1999-2000. The same three parameters were 
considered as discussed above for 2001: (1) The percentage of MMUs 
exhibiting a pattern of recurrent overexposures, as indicated by at 
least two of the valid measurements being above the applicable dust 
standard in a given year; (2) for those and only those MMUs exhibiting 
recurrent overexposures, the overall percentage of production shifts on 
which the DO was overexposed, as estimated by the percentage of valid 
measurements above the applicable dust standard; and (3) for the MMUs 
identified as exhibiting recurrent overexposures, the mean excess above 
the applicable dust standard, as calculated for just those valid 
measurements that exceeded the applicable dust standard in a given 
year.
    Although MSHA found minor differences between individual years, 
there was no statistically significant upward or downward trend in any 
of these three parameters over the 1990-1997 time period (see Table VI-
2). Beginning in 1999, however, there was a significant and persistent 
decrease in the average excess above the applicable dust standard 
(Parameter 3) for MMUs exhibiting recurrent overexposures. 
MSHA attributes this decrease to two important changes in the Agency's 
inspection program, beginning near the end of 1998. These changes, 
which both resulted in increased MSHA personnel presence, were: (1) An 
increase in the frequency of MSHA dust sampling at underground coal 
mines; and (2) initiation of monthly spot inspections at mines that 
were experiencing difficulty in maintaining consistent compliance with 
the applicable dust standard.

[[Page 10852]]



   Table VI-2.--Parameters Describing Overexposure to Respirable Coal Mine Dust, Based on Operator DO Samples
----------------------------------------------------------------------------------------------------------------
                                                                                      Parameter 3  (mg/
                                                         Parameter       Parameter              m \3\)
                1990-1997  1999-2000                    1      2   ---------------------------
                                                         (Percent)       (Percent)      1990-1997     1999-2000
----------------------------------------------------------------------------------------------------------------
Number of Years.....................................          10              10            8             2
-----------------------------------------------------
Median..............................................          52.6            20.1          1.24          1.00
-----------------------------------------------------
Mean................................................          51.0            20.5          1.26          1.00
(Std. Error)........................................          (1.36)          (0.30)       (0.023)        0.07
-----------------------------------------------------
2001................................................          51.6            20.8               1.08
----------------------------------------------------------------------------------------------------------------
Parameter 1: Percentage of MMUs exhibiting a pattern of recurrent overexposures.
Parameter 2: For those MMUs exhibiting a pattern of recurrent overexposures, the percentage of
  production shifts on which the DO was overexposed.
Parameter 3: for those MMUs exhibiting a pattern of recurrent overexposures, the mean excess above the
  applicable dust standard among valid DO measurements that exceeded the applicable dust standard.

Appendix VI.2 Application of the Attfield-Seixas Models

    Attfield and Seixas (1995) provide separate logistic regression 
models for CWP1+, CWP2+, and PMF as a function of cumulative dust 
exposure (mg-yr/m3). These models all have the following 
form:
[GRAPHIC] [TIFF OMITTED] TP06MR03.005

where p is the probability of disease at a specified age and cumulative 
exposure. The constant e is the base of the natural logarithms. The 
empirically estimated coefficients a0 (the intercept), 
a1, a2, and a3 differ for the three 
health effects considered and are presented in Table IV of Attfield and 
Seixas (op cit). The values for these coefficients are also shown in 
the Excel workbook (RiskRdxn.xlw) MSHA has placed into the public 
record as part of these proceedings. The coefficient (a3) of 
``rank'' refers to an additional effect of cumulative exposure to coal 
mine dust in central Pennsylvania or southeastern West Virginia, which 
the authors attribute to the rank of the coal mined in those areas. 
Since few mines in those areas are currently operating, MSHA did not 
employ this additional effect in its application of the Attfield-Seixas 
models (i.e., MSHA assumed that the value of the indicator variable for 
``rank'' is zero).
    From equation 1, assuming exposure outside central Pennsylvania and 
southeastern West Virginia, it follows that the prevalence of disease, 
assuming continued exposure at current levels and approximate linearity 
of the exposure effect, is (per thousand miners):
[GRAPHIC] [TIFF OMITTED] TP06MR03.006

Similarly, the prevalence of disease, assuming reduced cumulative 
exposure attributable to implementation of the proposed rules is (per 
thousand miners):
[GRAPHIC] [TIFF OMITTED] TP06MR03.007

Note that the ``reduced mean annual exposure'' is the current mean 
annual exposure (based on 2001 data) reduced by eliminating 
overexposures on just that percentage of shifts for which overexposures 
have been shown to currently occur. MSHA then estimated the impact of 
eliminating all overexposures on individual shifts by calculating (for 
ages 65, 73, and 80) the differences:
[GRAPHIC] [TIFF OMITTED] TP06MR03.008

It is these differences that are presented in Table VI-1. The 
calculations for each specific entry are detailed in the EXCEL 
workbook, RiskRdxn.xlw, which has been placed into the public 
record.\28\
---------------------------------------------------------------------------

    \28\ The method used here provides an approximation of the 
expected risk reduction ([Delta]), assuming approximate linearity of 
the exposure-response relationship over the exposure range of 
interest. This differs from the method used in the previous proposed 
rule, where lower bounds on the risk reduction were calculated. The 
calculations in the previous proposed rule defined
    [Delta]' = P y',-Px',
    where y' = y/x and x' = e a0+a1x age
    The previous method results in lower values than those shown in 
Table VI-1. For example, for ``CWP 1+'' among affected DO miners at 
age 73, applying the previous method to 2001 operator and MSHA data 
would have resulted in a calculated risk reduction of 16.3 per 
thousand instead of the 24.4 per thousand presented in Table VI-1. 
MSHA believes the method used in the current proposed rule more 
accurately represents the reduction in risk that can be expected if 
all individual shift overexposures are eliminated.

---------------------------------------------------------------------------

[[Page 10853]]

VII. Significance of Risk

    The proposed single sample and plan verification rules prevent 
respirable coal mine dust overexposures by identifying them and then 
requiring corrective actions. As discussed in the Health Effects 
Section, CWP is a progressive disease that develops after many years of 
cumulative exposure to respirable coal mine dust, which may include 
quartz, and is associated with material impairment of health and pre-
mature death (see Health Effects Section). The joint promulgation of 
the proposed single sample and plan verification rules would 
significantly reduce the risk of development of CWP over an 
occupational lifetime. The best available data were used to conduct the 
QRA.
    (A) Through the ``Benzene decision,'' the U.S. Supreme Court 
provided further guidance on determining and interpreting the 
significance of risks.

    It is the Agency's responsibility to determine, in the first 
instance, what it considered to be a ``significant'' risk. Some 
risks are plainly unacceptable. If, for example, the odds are one in 
a billion that a person will die from cancer by taking a drink of 
chlorinated water, the risk clearly could not be considered 
significant. On the other hand, if the odds are one in a thousand 
that regular inhalation of gasoline vapors that are 2% benzene will 
be fatal, a reasonable person might well consider the risk 
significant and take appropriate steps to decrease or eliminate it. 
Although the Agency has no duty to calculate the exact probability 
of harm, it does have an obligation to find that a significant risk 
is present before it can characterize a place of employment as 
`unsafe' (448 U.S. at 655).

    The industry recognizes the health significance of maintaining 
exposures at or below the applicable dust standard. For example, at the 
August 16, 2000 public hearing, the National Mining Association's 
representative Mr. Watzman, stated ``* * * (MSHA,) we don't want to see 
any miner overexposed. Our objective has been and will always be to 
maintain dust levels below the applicable dust standard.'' The United 
Mine Workers of America's written comments echoed the importance of 
reducing overexposures, ``Miners'' exposure to unhealthy levels of coal 
mine dust leads to the disabling and life shortening ``black lung'' 
disease [CWP].''
    The best estimates of reduction in risk for all categories of CWP, 
for miners who live to age 73, after a 45-year occupational exposure to 
respirable coal mine dust were: 2.3 per 1,000 affected non-designated 
occupation miners; 19.6 per 1,000 affected roofbolter designated areas 
miners; and, 24.4 per thousand affected designated occupation miners. 
These estimates quantitatively demonstrate MSHA's policy determination 
that there would be a significant reduction in risk of CWP as a 
consequence of the promulgation of these proposed rules.
    (B) There are many elements that compile a QRA. For each element of 
a QRA, there may be multiple assumptions (e.g., values of variables and 
sources of data) that could be applied. Various assumptions will differ 
in the extent to which they are less or more likely to occur (i.e., be 
representative). Assumptions may also have relative degrees of impact 
on the risk estimate, either increasing or decreasing it. To the extent 
that miners experience conditions that differ from the assumptions in 
the QRA, their risk of developing CWP will consequently be higher or 
lower. A ``conservative'' assumption in the QRA is one that results in 
a higher estimate of risk than a less ``conservative'' assumption 
would. Estimated benefits (i.e., the number of prevented cases of the 
outcome of concern, e.g., CWP) are greater under QRA assumptions that 
are ``conservative'' in this sense.\29\
---------------------------------------------------------------------------

    \29\ For example, in a hypothetical QRA there is a reduction in 
risk estimate for CWP of 2.4 per 1,000 affected miners, based on a 
relatively conservative assumption for a particular element (holding 
all other assumptions constant). A reduction in the risk estimate 
for CWP based on an equally likely although less conservative 
assumption is 1.0 per 1,000 affected miners, holding all other 
assumptions constant. Assuming that the population of affected 
miners is 20,000. The more conservative assumption would result in 
an estimated 48 (2.4/1,000 * 20,000) prevented cases of CWP compared 
to the less conservative assumption's 20 prevented cases of CWP.
---------------------------------------------------------------------------

    The discussion below identifies various elements of the QRA and how 
these choices may have affected the estimates in reduction of risk.
    i. The quantitative risk estimates are contingent on the 
representativeness of the exposure data in describing the exposures 
experienced by miners on all shifts. Currently, both operator and MSHA 
samples \30\, may be taken on production shifts that may not reflect 
production levels on the majority of non-sampled shifts.
---------------------------------------------------------------------------

    \30\ Valid MSHA samples require production to be at least 60 
percent of the average production for the last 30 days. Valid 
operator bimonthly samples must be taken on a normal production 
shift (i.e., a production shift during which the amount of material 
produced in a MMU is at least 50 percent of the average production 
reported for the last set of five valid samples) (30 CFR 70.100 
(k)(1)).
---------------------------------------------------------------------------

    Factors, such as mine ventilation and water sprays, mediate the 
amount of airborne respirable dust. Higher production is correlated 
with increased quantities of airborne respirable coal mine dust 
(Webster, et al., 1990; Haney, et al., 1993; O'Green, et al., 1994). 
Some earlier commenters, in these proceedings and before the Dust 
Advisory Committee, have asserted that production is reduced and/or 
dust controls are increased on sampled shifts.
    The estimates of risk reductions for affected miners are based on 
averages across those MMUs exhibiting a pattern of recurrent 
overexposures. In the QRA, the agency assumed representative operating 
conditions on those shifts sampled and extrapolated the results to all 
production shifts, including those that were not sampled. If there is 
diminished production and increased engineering controls on sampled 
shifts compared to the majority of non-sampled shifts, then this would 
mean that MSHA is underestimating the reduction(s) in risk to be 
expected from these proposed rules. (This is further discussed in the 
Benefits sections of the PREA and PV preamble).
    ii. The QRA applies the traditional coal miner work schedule of 8-
hours per day, 5-days per week, 48-weeks per year. Many of today's 
miners work longer hours per day, month, and year than the traditional 
work schedule. These longer work hours increase miners' cumulative 
exposure to respirable coal mine dust beyond what MSHA assumed in its 
risk estimates. Similarly, shorter work hours would decrease cumulative 
exposure below the values assumed in the QRA.
    iii. In their comments on the 2000 proposed rules, the National 
Mining Association (NMA) criticized MSHA's use of a 45-year 
occupational lifetime, stating ``the work experience of the vast 
majority of miners is far less than 45 years.'' Irrespective of the 
specific duration of a working lifetime of an individual worker or 
cohort of workers, health standards are promulgated to protect all 
workers from adverse health outcomes due to occupational exposure for 
an occupational lifetime. Under the Mine Act standards are set to 
protect miners for up to a full working lifetime (101 (a)(6)(A) (30 
U.S.C. 811(a)(6)(A)):


[[Page 10854]]


    The Secretary * * * shall set standards which most adequately 
assure on the basis of the best available evidence that no miner 
will suffer material impairment of health or functional capacity 
even if such miner has regular exposure to the hazards dealt with by 
such standard for the period of his working life. (emphasis added)

    Similarly, the Occupational Safety and Health Act, Public Law 51-
956 section 6(b)(5) states:

    The Secretary, in promulgating standards dealing with toxic 
materials or harmful physical agents under this subsection, shall 
set the standard which most adequately assures, to the extent 
feasible, on the basis of the best available evidence, that no 
employee will suffer material impairment of health or functional 
capacity even if such employee has a regular exposure to the hazard 
dealt with by such a standard for the period of his working life. 
(emphasis added).

    A 45-year ``working life'' (occupational lifetime) has 
conventionally been used in QRAs for occupational settings. For 
example, MSHA used a 45-year lifetime in its risk assessment for diesel 
particulate (66 FR 5526 and 66 FR 5706). Similarly, OSHA has used a 
working-life of 45 years in its QRAs to support health standards (see, 
for example, Benzene (52 FR 34460); Bloodborne Pathogens (65 FR 64004); 
Methylene Chloride (62 FR 1494); and 1,3-Butadiene, (61 FR 567467)). To 
the extent the proportion of miners' careers are shorter than 45 years, 
the actual benefits may be lower.
    iv. Due to the progressive nature of CWP even after occupational 
exposure has stopped (see Health Effects Section), the best estimate of 
the occupational-lifetime benefit of preventing respirable coal mine 
dust overexposures is based on the expected lifetime for all American 
males, 73 years of age.\31\ In the future, the extent to which coal 
miners have a greater life expectancy, the realized benefits would 
increase. For example, since females have a greater life expectancy 
than males, expected benefits will increase if the proportion of female 
miners increases substantially in the future.
---------------------------------------------------------------------------

    \31\ Conditional on their having reached 20 years of age 
(calculated from: the U.S. Census March 1997, Table 18; U.S. Census 
March 1997, Table 11).
---------------------------------------------------------------------------

    v. Applicable dust standards for RB-DAs are determined separately 
from the applicable dust standard shared by DOs and NDOs, even though 
they are on the same MMU. Since RB-DAs are often exposed to higher 
quartz concentrations than other miners on the same MMU, frequently, 
the RB-DA's applicable dust standard is lower than that for other 
miners working on the same MMU. Therefore, RB-DAs have their own 
percentage that exhibit a pattern of recurrent overexposures. 
Roofbolter DA MSHA samples were defined as samples with entity code 
900-0 through 999-9 and as a type 03 sample. Some MSHA RB-DA samples 
may have been incorrectly coded as a type 02 sample--an occasional 
problem with the data. Those incorrectly coded samples would not have 
been included in the QRA and therefore the number of RB-DAs with a 
pattern of recurrent overexposures may be underestimated.
    vi. Although the effect cannot be readily quantified, these rules 
would also reduce the cumulative exposure to respirable coal mine dust 
for those miners working on MMUs currently not exhibiting patterns of 
recurrent overexposures for either DOs and/or RB-DAs. Thus, the health 
benefit for all miners is expected to be greater than estimated for the 
sub-populations of miners in the QRA.
    MSHA has taken steps in the QRA to conduct a balanced analysis 
using available data. The data in the QRA have limitations, preventing 
MSHA from fully quantifying the frequency and average magnitude of 
overexposure of respirable coal mine dust for the entire population of 
underground coal miners whose cumulative exposure to respirable coal 
mine dust would be reduced due to the proposed rules. To the extent 
that MSHA has underestimated overexposure levels among underground coal 
miners, it has underestimated the reduction in risk for CWP and the 
number of prevented cases of CWP that would be realized through these 
proposed rules, over an occupational lifetime (For further discussion, 
see Benefits section of PREA and preamble).

VIII. Feasibility Issues

A. Technological Feasibility

    MSHA believes that the plan verification rule would be 
technologically feasible for the mining industry. An agency must show 
that modern technology has at least conceived some industrial 
strategies or devices that are likely to be capable of meeting the 
standard, and which industry is generally capable of adopting. American 
Iron and Steel Institute v. OSHA, (AISI-II) 939 F.2d 975, 980 (D.C. 
Cir. 1991); American Iron and Steel Institute v. OSHA, (AISI-I) 577 
F.2d 825 (3d Cir. 1978) at 832-835; and Industrial Union Dep't., AFL-
CIO v. Hodgson, 499 F.2d 467,478 (D.C. Cir. 1974).
    In designing the plan verification rule, MSHA has taken into 
account its experience and that of the operators to ensure that the 
rule provides additional protection from occupational exposure to 
respirable coal mine dust using current compliance technology (while 
encouraging technological improvements). For this reason, MSHA believes 
the proposed plan verification rule is technologically feasible. MSHA 
requires mine operators to utilize all feasible engineering or 
environmental controls, which are specified in the mine ventilation 
plan, to maintain concentrations of respirable dust in the work 
environment of MMUs at or below the applicable dust standard. Mine 
operators therefore would not be required to implement engineering or 
environmental controls that were not technologically feasible.

B. Economic Feasibility

    MSHA believes that the proposed Plan verification rule would be 
economically feasible for the underground coal mining industry. The 
proposed Plan verification rule would result in net compliance cost 
savings of approximately $2.1 million yearly. (Although implementing 
the proposed Plan verification rule would cost about $4.5 million 
yearly, there would be offsetting yearly savings of about $3.8 million 
from reduced citations and the elimination of operator abatement 
sampling; $2.2 million from the elimination of operator bi-monthly 
sampling; $0.3 million resulting from a reduction in MSHA-ordered mine 
closures; and $0.3 million from reduced payout by operators for Black 
Lung cases). Underground coal operators would also obtain a yearly cost 
savings of approximately $3.0 million in reduced penalty costs 
associated with the reduction in operator citations arising from the 
proposed plan verification rule. The proposed plan verification rule 
would therefore provide a total yearly cost savings (including net 
reduced penalty costs) of $5.1 million to the underground coal mining 
industry.

IX. Preliminary Regulatory Economic Analysis

A. Costs and Benefits: Executive Order 12866

1. Compliance Costs
    The proposed plan verification rule would impose a yearly net 
compliance cost savings to underground coal operators of about $2.1 
million. Although implementing the proposed plan verification rule 
would cost about $4.5 million yearly, there would be offsetting yearly 
savings of $6.6 million. The cost savings consist of: $3.8 million due 
to reduced citations and the elimination of operator abatement

[[Page 10855]]

sampling; $2.2 million resulting from the elimination of bi-monthly 
sampling; $0.3 million resulting from a reduction in MSHA-ordered mine 
closures; and $0.3 million resulting from reduced Black Lung payouts by 
underground coal operators. These costs include net first year 
compliance costs of approximately $2.1 million.
2. Benefits
    This benefits analysis is in support of the proposed single sample 
and plan verification rules, and updates information used in the 
single-shift sample (65 FR 42068) and plan verification proposed rules 
(65 FR 42122). It has been updated to include the revised QRA;\32\ the 
reduction in the number of active mines (and miners); and more recent 
information on the DOL's Black Lung Compensation Program. As a result, 
MSHA believes it has more comprehensively quantified the expected 
reduction in risk of CWP and the associated benefits (i.e., the number 
of prevented cases of CWP) for those miners currently subject to a 
pattern of recurrent overexposures to respirable coal mine dust.\33\
---------------------------------------------------------------------------

    \32\ The revised QRA is published in full in section IV.b of the 
2003 single sample reopening notice and section VI of the 2003 plan 
verification NPRM. The revised QRA has been expanded to include 
quantitative estimates of the reduction in CWP for affected 
roofbolters working in designated areas (RB-DA).
    \33\ The pattern of recurrent overexposure is defined by a MMU 
having any combination of two or more samples in excess of the 
applicable dust standard within a one-year period.
---------------------------------------------------------------------------

    MSHA notes that the methodology will almost certainly lead to an 
underestimate of the number of MMUs with recurrent overexposures. This 
is due to the fact that the agency must rely on samples taken for 30 or 
fewer shifts each year for each MMU. MSHA estimates that each MMU 
averages 384 production shifts per year, so samples are taken for only 
about 8 percent of all shifts. An MMU exhibits a pattern of recurrent 
overexposure when valid samples at the MMU exceed the applicable dust 
standard on at least two shifts during a year. MSHA uses data for those 
MMUs exhibiting such a pattern to estimate miners' overexposures and 
the reduction in dust that would be inhaled by miners if dust levels 
were reduced to the exposure limit on every shift.
    Due to the fact that only a small fraction of shifts are sampled, 
this approach will very likely underestimate the total number of shifts 
with excessive exposures. There is no straightforward way to determine 
the extent of the underestimate, but the following illustrates the 
likelihood of not identifying MMUs that experience excessive exposures. 
The table below shows the probability that an MMU will not exhibit a 
pattern of recurrent overexposures (i.e., 2 or more overexposures on 30 
randomly sampled shifts out of 384 working shifts in a year) when there 
are actually ``n'' noncompliant shifts during the year. For example, if 
an MMU exceeds the applicable standard on 25 shifts during a year, 
there is a 40 percent probability that fewer than two of the 30 samples 
for that MMU would be taken on those 25 shifts. Therefore, there is a 
good chance that such an MMU would not be identified as having a 
pattern of recurrent exposures. It should also be noted, however, that 
only 6.5 percent (i.e., 25/384) of production shifts would, on average, 
be out of compliance at such an MMU. This is substantially below the 
average of 20 percent of shifts found out of compliance at MMUs MSHA 
has identified as exhibiting a recurrent pattern.

  Table IX-2-1.--Relationship between the number of noncompliant shifts
       and the probability of not detecting a pattern of recurrent
                     overexposures for a single MMU
------------------------------------------------------------------------
                                                        Probability (%)
          Number of noncompliant shifts \34\              of not being
                                                        identified \35\
------------------------------------------------------------------------
5....................................................               94.9
10...................................................               82.0
15...................................................               67.0
20...................................................               52.5
25...................................................               40.0
30...................................................               29.7
35...................................................               21.6
40...................................................               15.4
45...................................................               10.9
50...................................................                7.5
55...................................................                5.1
60...................................................                3.5
65...................................................                2.3
70...................................................                1.5
75...................................................                1.0
80...................................................                0.6
85...................................................                0.4
90...................................................                0.3
95...................................................                0.2
100..................................................               0.1
------------------------------------------------------------------------
\34\ Number of individual shift overexposures out of 384 shifts in a
  year.
\35\ Probability (%) that an MMU will fail to display a pattern of
  recurrent overexposures, based on 30 sampled shifts, given ``n''
  individual shift overexposures out of 384 shifts in a year.

    Occupational exposure to excessive levels of respirable coal mine 
dust, which includes quartz in varying proportions, imposes significant 
health risks. These include the following adverse health outcomes: 
simple coal worker's pneumoconiosis (simple CWP), progressive massive 
fibrosis (PMF), silicosis, and chronic obstructive pulmonary disease 
(COPD) (e.g., asthma, chronic bronchitis, emphysema) (See the Health 
Effects, section V., of the plan verification proposed rule and section 
VII of the single-shift sample proposed rule (65 FR 42068) for a more 
complete discussion). Cumulative exposure to respirable coal mine dust 
is the main determinant in the development of both simple CWP and PMF 
although other factors, such as the percentage of quartz in the 
respirable dust and the type of coal, also affect the risk of miners 
developing simple CWP and PMF (Jacobsen, et al., 1977; Hurley, et al., 
1987; Kuempel, et al., 1995; Attfield and Morring, 1992; Attfield and 
Seixas, 1995). The true magnitude of occupationally induced simple CWP 
and PMF among today's coal miners is unknown, although prevalence 
estimates are available from various surveillance systems. The overall 
prevalence rate of simple CWP, Categories 1, 2, 3, and PMF combined was 
2.8 percent among all miners examined in the Miners' Choice program 
during FY 2000-2002 (see Health Effects discussion). The combined 
prevalence rate of simple CWP and PMF for underground coal miners was 
3.8 percent during the same time period. Studies from the Coal Workers 
X-ray Surveillance Program (CWXSP) indicate a decline in the prevalence 
of CWP from 11 percent in the 1970s to 2.8 percent in the sixth round 
of CWXSP (1992-1996)(NIOSH, Table 2-11, 1999).
    The proposed single sample and plan verification rules present 
MSHA's strengthened plan to meet the Mine Act's requirement that a 
miner's exposure to respirable coal mine dust be at or below the 
applicable dust standard on each and every shift.
    The QRA estimates the reduction in risk for CWP as a result of 
reducing respirable coal mine dust concentrations over a miners' 45-
year occupational lifetime to be no more than the applicable dust 
standard on just that percentage of shifts currently exhibiting a 
pattern of recurrent overexposures.\36\ The term ``affected'' is used 
to identify those miners who work on a MMU or RB-DA where there is a 
recurrent

[[Page 10856]]

pattern of overexposure to respirable coal mine dust. There are three 
types of affected miners for whom reduction in risk estimates were 
calculated:
---------------------------------------------------------------------------

    \36\MMUs with a recurrent pattern of overexposure are defined as 
those MMUs with two or more of the DO samples exceeding the 
applicable dust standard. RB-DAs with a recurrent pattern of 
overexposure are defined as those with two or more RB-DA samples 
exceeding the applicable dust standard. (See the QRA section IV.b of 
the 2003 single sample reopening notice and section VI of the 2003 
plan verification NPRM for details).
---------------------------------------------------------------------------

    [sbull] DOs: Designated Occupation Miners.
    [sbull] NDOs: Faceworkers neither classified as a DO nor subject to 
a separate applicable dust standard applicable to a Designated Area.
    [sbull] RB-DA: Roofbolter Designated Area Miners.
    Since DOs and NDOs share the same applicable dust standard, the 
definition of recurrent pattern of overexposure for DOs and NDOs is the 
same. It is determined by the pattern of recurrent overexposures 
observed for DOs. This pattern of recurrent overexposure is sometimes 
referred as the MMU's pattern of recurrent overexposures.
    Applicable dust standards for RB-DAs are determined separately from 
the applicable dust standard shared by DOs and NDOs on the same MMU. 
Since RB-DAs are often exposed to higher quartz concentrations than 
other occupations (miners) on the same MMU, frequently, the RB-DA's 
applicable dust standard is more stringent (i.e., a lower applicable 
dust standard) than that for other occupations working on the same MMU. 
A separate pattern of recurrent overexposure is defined for the RB-DAs.
    To predict the benefits, MSHA applied its best estimate of 
reduction in risk of CWP for each type of affected miner (DO, NDO, and 
RB-DA) to estimated sub-populations of those affected miners.
    The factors taken into account to estimate each of the sub-
populations are:
    [sbull] A recent snapshot of the number of active MMUs and RB-DAs. 
(MSHA, Table, May 14, 2002)
    [sbull] The pattern of recurrent overexposures for affected MMUs 
and RB-DAs.
    [sbull] The distribution of MMUs by mine size (i.e., fewer than 20 
employees; 20 to 500 employees; and, more than 500 employees) and the 
number of production shifts (i.e. 1, 2, or 3) (MSHA, Table, July 10, 
2002 for DOs and NDOs; and MSHA, Table, September 4, 2002).
    [sbull] The average number of miners on a shift for each category.
    [sbull] One DO on each MMU.
    [sbull] Six NDOs for each MMU.
    [sbull] The number of RB-DAs on a shift, varied by mine size. (See 
Table IX-2-3 for specific numbers).
    Since NDOs and the DO on the same MMU share the same pattern of 
recurrent overexposures (i.e., 57.0 percent) and the same distribution 
of MMUs by mine size and number of production shifts, the estimates of 
affected populations of DOs and NDOs are both included in Table IX-2-2. 
The estimated sub-populations of affected miners working in DOs and 
NDOs are calculated as follows:
    (1) The distribution of active MMU entities was determined by mine 
size and number of production shifts (MSHA, Table, July 10, 2002).
    (2) The number of MMU entities that exhibited a pattern of 
overexposures for DOs (57.0 percent) was determined using operator and 
MSHA samples for respirable coal mine dust collected during the 
calendar year 2001 (MSHA data file: DO--2001.zip).
    (3) MSHA estimated the number of DOs to have been affected by 
recurrent overexposures by simultaneously applying the percentage of 
MMUs found to have patterns of recurrent overexposure (57.0 percent) to 
the number and type of active MMU entities by mine size (833 active 
MMUs; MSHA, Table May 14, 2002) and the distribution of production 
shifts by mine size mentioned in steps (1) and (2). MSHA estimates 
there would be 475 affected active MMUs.
    (4) The number of miners working in the DO position is proportional 
to the number of shifts each MMU is in production per day. The 
distribution of the number of affected MMU entities by production 
shifts (from step 3) is applied to the estimated number of DOs per MMU 
entity. Typically, there is one miner for each DO for each shift.
    (5) Typically, six other miners operating as NDOs simultaneously 
work on the same MMU. Therefore, the number of affected NDOs is six 
times the number of affected DOs.
    (6) Table IX-2-2 presents the estimated number of affected MMUs, 
DOs, and NDOs, by mine size and number of production shifts. The total 
number of affected DO and NDO miners is estimated to be 6,307.
    Since RB-DAs and the combination of DOs and NDOs do not share the 
same pattern of recurrent overexposures, nor the distribution of MMUs 
by mine size, the estimates of affected populations of RB-DAs are 
presented in their own table (Table IX-2-3). The estimated sub-
populations of affected miners working in the RB-DAs are calculated as 
follows:
    (1) The distribution of active RB-DA entities was recently 
determined by mine size and number of production shifts (MSHA, Table 
September 4, 2002).
    (2) The number of RB-DA entities that exhibit a pattern of 
overexposures (29.4 percent, 194/659 RB-DAs) was determined using 
operator and MSHA samples for respirable coal mine dust collected 
during the calendar year 2001 (MSHA data file: RB-DA2001.zip)
    (3) MSHA estimated the number of RB-DA entities affected by 
recurrent overexposures by simultaneously applying the percentage of 
RB-DAs found to have patterns of recurrent overexposure (29.4 percent) 
to the number and type of active RB-DA entities by mine size (449 
active RB-DAs; MSHA, Table May 14, 2002) and the distribution of 
production shifts by mine size mentioned in steps (1) and (2). MSHA 
estimates there would be 132 affected active RB-DAs.
    (4) The number of miners working in an RB-DA entity is proportional 
to the number of shifts each RB-DA is in production per day. The 
distribution of the number of affected RB-DA entities by production 
shifts (determined in step 3) is applied to the estimated number of 
roofbolters per RB-DA entity. The typical number of miners per RB-DA 
varies by mine size. It is MSHA's experience that, on average, one 
roofbolter works within the RB-DA in coal mines with fewer than 20 
employees, one and one half in coal mines with 20 to 500 employees, and 
two in coal mines with more than 500 employees.
    (5) Table IX-2-3 presents the estimated number of affected RB-DAs 
and miners by mine size and number of production shifts. The total 
number of affected miners working within an RB-DA is estimated to be 
368.
    The total number of affected miners working within the specified 
DO, NDO, and RB-DA positions among the faceworkers in underground coal 
mines is estimated to be 6,675.

[[Page 10857]]



  Table IX-2-2.--Estimated Number of Affected Mechanized Mining Units a (MMUs) and Affected Underground Coal Miners, by Production Shifts and Mine Size
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                         Mine size by number of employees                                                          Totals
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                    Less than 20 employees      20 to 500 employees          Greater than 500
                                 ------------------------------------------------------         employees                                        Total
   Number of production shifts                                                         --------------------------- NMUs n=   DOS b    NDO c    affected
                                  NMUs n=   DOS b    NDO c   NMUs n=   DOS b    NDO c             DOS b    NDO c               n=       n=     miners on
                                              n=       n=                n=       n=    NMUs n=     n=       n=                                  NMUs
--------------------------------------------------------------------------------------------------------------------------------------------------------
One.............................       98       98      588       24       24      144        0        0        0      122      122      732         854
Two.............................       16       32      192      264      528    3,168        0        0        0      280      560    3,360       3,920
Three...........................        0        0        0       55      165      990       18       54      324       73      219    1,314       1,533
                                 ----------
    Totals......................      114      130      780      343      717    4,302       18       54      324      475      901    5,406      6,307
--------------------------------------------------------------------------------------------------------------------------------------------------------
\a\ Affected MMUs in production are estimated by applying the observed percentage of MMUs' production shifts by mine size (as of July 10, 2002) to the
  snapshot of active MMUs as of May 14, 2002, by mine size, and multiplied by 0.570 (since fifty-seven percent of MMUs have a pattern of recurrent
  overexposures) (MSHA Table, July 10, 2002; MSHA Table, May 14, 2002).
Where:
\b\ DO = Designated Occupational Miners = (MMUs * 1 * production shifts).
\c\ NDO = Non-designated Occupational Miners = (MMUs * 6 * production shifts).


  Table IX-2-3.--Estimated Number of Affected Roofbolter Designated Areas (RB-DAs) and Affected Underground Coal Miners, by Production Shifts, and Mine
                                                                          Size
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                            Mine Size by Number of Employees
---------------------------------------------------------------------------------------------------------------------------------------------------------
          Number of Affected RB-DAs \a\            Less Than 20 Employees      20 to 500 Employees        Greater than 500               Totals
-----------------------------------------------------------------------------------------------------         Employees        -------------------------
                                                                                                     --------------------------                 Total
                                                                                                                                              miners on
           Number of production shifts             RB-DAs  n=   Miners n=    RB-DAs n=    Miners n=    RB-DAs n=    Miners n=    RB-DAs n=   affected RB-
                                                                                                                                                 DAs
--------------------------------------------------------------------------------------------------------------------------------------------------------
1...............................................           22           22            6            9            0            0           28           31
2...............................................            5           10           83          249            0            0           88          259
3...............................................            0            0           12           54            4           24           16           78
                                                 --------------
    Total.......................................           27           32          101          312            4           24          132          368
=================================================
Number of Miners per RB-DA......................             1.0
                                                             1.5
                                                             2.0            ...........  ...........
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Affected Roofbolter Designated Areas (RB-DAs) in production are estimated by applying the observed percentage of RB-DAs' production shifts by mine
  size (as of September 4, 2002) to the snapshot of active RB-DAs as of May 14, 2002, by mine size, and multiplied by 0.294 (since 29.4 percent of RB-
  DAs have a pattern of recurrent overexposures) (MSHA Table, July 10, 2002; MSHA Table, May 14, 2002). The number of miners per RB-DA varies with mine
  size and is applied to the estimated number of RB-DAs and the number of production shifts to determine the total number of affected faceworkers.

    The total number of cases of simple CWP categories 1, 2, 3 or PMF 
that would be prevented is determined by applying the estimated number 
of affected miners to our best estimates of reductions in risk. The 
estimates of reductions in risk for the three sub-populations of 
affected miners (24.4 per thousand DOs, 2.3 per thousand NDOs, and 19.6 
per thousand RB-DAs) are applied to the respective estimates of 
affected sub-populations of faceworkers (901 DOs, 5,406 NDOs, and 368 
RB-DAs).\37\ Table IX-2-4 presents a summary of the estimated number of 
cases among groups of simple CWP and PMF that would be prevented among 
the affected miners working at the 57.0 percent of MMUs and the 29.4 
percent of RB-DAs determined to exhibit a pattern of recurrent 
overexposures, by limiting their exposures to respirable coal mine dust 
to no more than the applicable dust standard on each and every shift. 
For all categories of simple CWP and PMF combined, MSHA estimates a 
minimum of 42 fewer cases among affected miners than would otherwise 
occur without the promulgation of the proposed single sample and plan 
verification rules. Thirteen of these cases would be the most severe 
form of coal miner's pneumoconiosis, PMF, and as such, these cases 
could be interpreted as prevented premature deaths due to occupational 
exposure to respirable coal mine dust. Since simple CWP is a 
progressive disease and predisposes the development of PMF, it is 
important that simple CWP also be prevented (Balaan, et al., 1993).
---------------------------------------------------------------------------

    \37\ See the Quantitative Risk Assessment (section VI. of the 
Plan Verification Notice of Proposed Rule Making in today's Federal 
Register) for details describing the methodology used to calculate 
the reduction of risk among the affected sub-populations and Table 
VI-1 for a summary of reduction in risk estimates.
---------------------------------------------------------------------------

    The benefits that would accrue to coal miners exposed to respirable 
coal mine dust and to operators, and ultimately to society at large, 
are substantial and take a number of forms. These proposed rules would 
reduce a substantial health risk to underground coal miners, lowering 
the potential for illnesses and premature death and their attendant 
costs to miners, their employers, their families, and society.
    These rules should realize a positive economic impact on the 
Department of Labor's (DOL's) Black Lung Program and relatedly on 
operators. The Black Lung Program compensates eligible miners and their 
survivors for benefits under the Black Lung Benefits Act. This program 
provides monthly payments and medical benefits (diagnostic and 
treatment) to miners who are determined to be totally disabled by black 
lung disease, including cases of PMF and simple CWP. In 1986, DOL's 
Employment Standards Administration

[[Page 10858]]

reported that 12 percent of approved cases to receive benefits within 
the Black Lung Program were identified as cases of PMF based on chest 
radiographs, while 64 percent had simple CWP based on chest radiographs 
(ESA, 1986). For miners who stopped working in coal mines after 1969 
and for whom DOL can establish that the miner worked for the same 
operator for at least one calendar year, and that miner had at least 
125 working days in that year, that operator is financially responsible 
for the miner's black lung benefits payments. If a responsible operator 
cannot be identified for an eligible miner, benefits payments are made 
by the Black Lung Disability Trust Fund.
    To the extent that the proposed single sample and plan verification 
rules reduce overexposures to respirable coal mine dust (which includes 
quartz), there should be fewer Black Lung Program cases. Therefore, 
over time, the associated financial outlay by responsible operators 
through either payments made into the Black Lung Disability Trust Fund, 
insurance premiums, or direct payments of black lung benefits should be 
lower than would otherwise occur. A decrease in black lung 
beneficiaries could help reduce the financial obligation of the Black 
Lung Program (see discussion in Chapter IV of the accompanying PREA for 
details: http://www.msha.gov/FLEX.HTM). In fiscal year 2000, 386 claims 
for Black Lung Benefits were accepted as new cases; 71 percent (273 
cases) are the financial responsibility of coal operators (ESA, OWCP 
2000 Annual Report).\38\
---------------------------------------------------------------------------

    \38\ The OWCP 2001 report is not representative of current 
trends because of recent changes to rules governing OWCP proceedings 
effective January 20, 2001 (Peed, September 12, 2002). Therefore, 
MSHA used information from the OWCP 2000 report.
---------------------------------------------------------------------------

    MSHA's quantitative estimate of benefits demonstrates and 
qualitative discussions punctuate that these proposed rules will have a 
significant positive impact on the health of the nation's coal miners 
when promulgated. Yet, due to the limitations in these data, MSHA 
believes its benefits estimates are likely to understate the number of 
cases of simple CWP and PMF that would be prevented over an 
occupational lifetime. As discussed in the significance of risk 
sections of the previously published single-shift sample (65 FR 42068) 
and plan verification (65 FR 42122) notices and as revised in the plan 
verification NPRM, the data used to estimate the average overexposure 
which will be prevented may not represent typical environmental 
conditions and the associated respirable coal mine dust exposure levels 
in underground coal mines.
    The degree to which the exposure level of respirable coal mine dust 
on sampling shifts may not be representative of typical exposure levels 
is affected by the following factors:
    (1) There exists a positive relationship between coal production 
and generation of respirable coal mine dust. While other factors may 
mediate the amount of airborne respirable dust, such as ventilation 
and water sprays, on average, higher production is correlated with 
increased quantities of airborne respirable coal mine dust (Webster, 
et al., 1990; Haney, et al., 1993; O'Green, et al., 1994);
    (2) Current sampling procedures permit sampling measurements to 
be taken at the mid-range of the distribution of the level of 
production--MSHA sampling measurements must be taken on shifts with 
production at least 60 percent of the average production during the 
last 30 days and the operator must have at least 50 percent of 
average production for the last valid set of five bimonthly samples 
for MSHA and operator samples, respectively;
    (3) Miners have reported, and MSHA data have demonstrated lower 
levels of production on sampling shifts versus non-sampling shifts; 
\39\
---------------------------------------------------------------------------

    \39\ Mine Safety and Health Administration. ``Report of the 
Statistical Task Team of the Coal Mine Respirable Dust Task Group.'' 
September 1993.
---------------------------------------------------------------------------

    (4) On some sampling shifts, miners have reported that more 
engineering controls may be engaged than on other shifts, thus 
reducing the measured amount of respirable coal mine dust;
    (5) MSHA analyses have demonstrated, even when controlling for 
production, in mines with fewer than 125 employees, on continuous 
mining MMUs, respirable coal mine dust exposures were much higher 
during the unannounced Spot Inspection Program (SIP) sampling shifts 
than on shifts operators sampled--this is consistent with the effect 
of increasing engineering controls on shifts during which bimonthly 
samples are conducted compared to the level of use of engineering 
controls on shifts for which the operator does not expect sampling 
to be conducted, given the same production level;\40\
---------------------------------------------------------------------------

    \40\ Mine Safety and Health Administration. ``Report of the 
Statistical Task Team of the Coal Mine Respirable Dust Task Group.'' 
September 1993.
---------------------------------------------------------------------------

    (6) Across mine size, designated area samples have had greater 
dust levels for shifts on which unannounced compliance sampling 
occurred compared to operator sampling shifts--in one study they 
differed by at least a factor of 40 percent in large mines and 100 
percent in the smallest mines;\41\
---------------------------------------------------------------------------

    \41\ Mine Safety and Health Administration. ``Report of the 
Statistical Task Team of the Coal Mine Respirable Dust Task Group.'' 
September 1993. Pp. 211-212.
---------------------------------------------------------------------------

    (7) Existing MSHA technical information indicates that some 
reduction in production levels occurs during some sampling periods 
on longwalls (Denk, 1990);
    (8) Longer work hours increase miners' cumulative exposure to 
respirable coal mine dust, which includes quartz, beyond what was 
assumed in our risk estimates (``Length of Shift'' survey, MSHA 
Office of Coal Mine Safety and Health); and
    (9) Because of heavy, physical work, some miners may have higher 
breathing rates and inhale more respirable coal mine dust, including 
quartz, than other miners exposed to the same airborne dust 
concentrations.

    Although the effects cannot readily be quantified, to the extent 
that these rules will also reduce the cumulative exposure to respirable 
coal mine dust among some miners working in those MMUs currently not 
exhibiting a pattern of overexposures, it is reasonable to expect an 
incremental benefit among that sub-population of coal miners. Likewise, 
to the extent that the cumulative exposure to respirable coal mine dust 
affects other adverse health outcomes, such as silicosis and chronic 
obstructive pulmonary disease, it is reasonable to expect a reduction 
in the number and/or severity of cases for these diseases among 
underground coal miners.
    Further, MSHA firmly believes that non compliance determinations 
based on single-sample measurements will significantly improve working 
conditions for miners because overexposures will be more readily 
identified and appropriate corrective action will be taken to reduce 
respirable dust levels. This is because individual sample results will 
not be masked due to the averaging of multiple samples. The health 
effects of individual shift overexposures was addressed in 
Consolidation Coal Company versus Secretary of Labor 8 FMSHRC 890, 
(1986), aff'd 824 F. 2d 1071, (D.C. Cir. 1987). In that case, the 
Commission found that each episode of a miner's overexposure to 
respirable dust significantly and substantially contributes to the 
health hazard of contracting chronic bronchitis or coal workers 
pneumoconiosis, diseases of a fairly serious nature.
    Since the proposed single sample rule would also apply to surface 
coal mines, it is reasonable to expect that the cumulative exposure of 
some surface coal miners would also be lowered, providing them with 
increased health protection.
    As indicated elsewhere in this preamble, three significant studies 
have been published in the last 10 years that examined the current 
federal program to control respirable coal mine dust in U.S. mines. 
They include the MSHA Respirable Dust Task Group Report, NIOSH's 
Criteria Document on Occupational Exposure to Respirable

[[Page 10859]]

Coal Mine Dust, and the Report of the Secretary of Labor's Advisory 
Committee on the Elimination of Pneumoconiosis Among Coal Workers. The 
individuals that contributed to these reports represented a wide 
spectrum of society including health professionals, mine operators, 
miners and their representatives, academia, engineers, lawyers, 
physicians, and health and safety specialists. While recognizing that 
significant progress has been made to reduce respirable dust levels in 
coal mines, these reports all concluded that there are existing 
practices in the federal program that should be changed to provide 
miners with improved health protection. This rulemaking was initiated 
to address many of the recommendations outlined in those studies.
    The primary benefit of the changes recommended by the authors of 
the various studies, and subsequently in this proposal, is to reduce 
occupational lung disease among coal miners by improving the existing 
federal program to control exposure to respirable coal mine dust and 
quartz. That benefit is addressed in detail in this section. There are, 
however, other significant intangible benefits that will result from 
these program improvements.
    As stated in the report of the Advisory Committee, one of MSHA's 
primary objectives must be to restore the confidence of individual 
miners that the federal program to control respirable dust will protect 
their health. The testimony of miners and their representatives made 
during the deliberations of at least two of the study groups found that 
coal miners believe that MSHA and operator sampling results are not 
representative of the mine environment to which they are exposed during 
normal mining operations. Consequently, many miners believe that 
overexposures are not being identified and corrected. This belief is 
attributable to several factors including, MSHA's policy of accepting 
as valid samples that were taken at production levels significantly 
below normal; the use of dust control measures during sampling that are 
not incorporated in the approved ventilation plan; and the averaging of 
multiple-shift sample results which can mask individual overexposures 
and prevent action from being taken to correct the condition. All of 
these practices are addressed in this proposal and, therefore, should 
significantly improve miner confidence that MSHA and operator sampling 
results are typical of the operating conditions to which they are 
routinely exposed.
    The requirement that operator sampling results be used by MSHA to 
make compliance determinations has been unfairly perceived by some as 
fundamentally flawed because operators allegedly have conflicting 
objective of avoiding citations and protecting miner health. This 
perception is difficult to address. As recommended by the Advisory 
Committee, this proposal eliminates the requirement that operator 
samples be used for compliance purposes. Operators will only be subject 
to enforcement action on their sample results if they fail to take 
action to correct any overexposure. Since only MSHA samples taken 
during unannounced inspections will be used to make compliance 
determinations, any real or perceived opportunity by mine operators to 
inappropriately impact sampling results will be eliminated or 
significantly reduced.
    All of the studies recognized that significant improvements in 
preventing overexposure can occur if real-time continuous monitors were 
available. Such devices would allow exposure levels to be monitored 
during the production shift and action could be taken during the shift 
to prevent overexposure as miners approached the upper limit. This is 
in contrast to the current system that requires samples to be sent to a 
laboratory for analysis and, as a result, only allows for overexposures 
to be recorded rather than prevented. This proposal recognizes that the 
potential for the introduction of such continuous monitoring devices is 
likely in the near future. As a result, provisions are included for the 
use of such instruments in lieu of the current approved sampling 
devices. Accordingly, this proposal encourages the development and 
introduction of this new technology into coal mines to benefit miner 
health.
    MSHA's belief that the projected 42 prevented cases of simple CWP 
and PMF over a 45-year working life likely understates the true number 
of cases of simple CWP and PMF is further supported by the fact that 
during the past few years, the Black Lung Benefits Program has been 
approving roughly 400 claims each year. Most of these claims come from 
individuals whose occupational exposure to respirable coal mine dust 
occurred under the current respirable coal mine dust program, including 
the 2.0 mg/m3 standard, which began in 1972 (ESA, September 
19, 2002). The observation that roughly 400 claims have been approved 
each year, for the past several years, supports MSHA's belief that the 
true lifetime occupational health benefits of the proposed rules are 
higher than MSHA has been able to quantify. Even assuming that over 
time, the number of new claims would decline in future years simply due 
to the continuing decline in the number of coal miners, MSHA expects 
that assuring future exposures are maintained below the applicable dust 
standard would reduce the number of new cases of CWP than would 
otherwise occur.
    In addition to the cases of simple CWP and PMF that would be 
prevented among the miners working on affected MMUs and RB-DAs, other 
health benefits would also be realized because the cumulative exposure 
to respirable coal mine dust would be limited to no more than the 
applicable standard on each and every shift. Health benefits associated 
with a reduction in exposures to respirable coal mine dust would 
include a decrease in incidence of silicosis, asthma, chronic 
bronchitis, and emphysema.
    All cases of simple CWP and PMF, which MSHA expects to be prevented 
through promulgation of the single sample and plan verification rules 
and attributable to eliminating individual shift overexposures, are not 
expected to materialize immediately after overexposures have been 
substantially reduced or eliminated. Because these diseases typically 
arise after many years of cumulative exposure, allowing for a period of 
latency, and the pre-existing occupational exposure histories of 
members of the current coal mining workforce, the beneficial effects of 
reducing exposures are expected to become evident only after a 
sufficient time has passed so that the reduction in cumulative exposure 
could have its effect. The total realized benefits would not be fully 
evident until after the youngest of today's underground coal miners 
retire. If the size of this workforce substantially changed in the 
future and the projected pattern of prevented overexposures remained 
the same, the number of cases of prevented simple CWP and PMF would 
need to be adjusted to account for the change.
    Various data, assumptions and caveats were used to conduct the 
benefits analyses. Therefore, MSHA requests any information which would 
enable it to conduct more accurate analyses of the estimated health 
benefits of the single sample and plan verification rules, both 
individually, and in combination.

[[Page 10860]]



 Table IX-2-4.--Over a Working Lifetime Among Affected Miners, Estimated Number of Cases of CWPa and PMFb Prevented Due to the Implementation of Single
                                                              Sample and Plan Verification
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                           Simple CWP categories 1,   Simple CWP categories 2              PMF
                                                                                 2, 3 or PMF                or 3 or PMF        -------------------------
                       Type of miner                           Affected  ------------------------------------------------------
                                                             miners,  n=   Reduction     Prevented    Reduction     Prevented    Reduction    Prevented
                                                                           in risk\c\   cases,  n=     in risk     cases,  n=     in risk     cases,  n=
--------------------------------------------------------------------------------------------------------------------------------------------------------
Affected Designated Occupational Miners\d\.................          901    24.4/1000          22.0    15.5/1000          14.0     7.6/1000          6.8
Affected Non-Designated Occupational Miners\e\.............        5,406     2.3/1000          12.4     1.5/1000           8.1     0.7/1000         3.18
Affected Roofbolters in Designated Areas\f\................          368    19.6/1000           7.2    12.1/1000           4.5     6.0/1000          2.2
==========================================================================
--------------------------------------------------------------------------------------------------------------------------------------------------------
\a\ Simple CWP: simple coal workers' pneumoconiosis.
\b\ PMF: progressive massive fibrosis.
\c\ Reduction in Risk per 1,000 affected miners, over a 45-year working lifetime, at age 73.
\d\ Affected Designated Occupation (DO) Miners: includes all miners who work at the 57.0 percent of the Mechanized Mining Units under consideration and
  who are exposed to dust concentrations similar to the DO, over a 45-year occupational lifetime.
\e\ Affected Non-Designated Occupation (NDO) Miners: includes all underground faceworkers under consideration who are not classified as the DO or a
  designated area roofbolter.
\f\ Affected Roofbolter Designated Area (DA) Miners: includes all miners working as roofbolters in the 29.4 percent of roofbolter designated areas
  exhibiting a pattern of recurrent overexposures.
\g\ The total miners affected (6,675) is a sub-population of the estimated number of underground coal miners (12,317) working at the mine face.

B. Regulatory Flexibility Certification and Regulatory Flexibility 
Analysis

    MSHA has consulted with the Chief Counsel for Advocacy on this 
proposed rule and on the Agency's certification of no significant 
economic impact on a substantial number of small entities covered by 
this rule. Consistent with Agency practice, notes of any meetings with 
the Chief Counsel's office on these rules, or any written 
communications, will be placed in the rulemaking record.
    Using both definitions of small mines, one with fewer than 20 
employees and one with 500 or fewer employees, the estimated compliance 
costs of the proposed rule is either negative or substantially less 
than 1 percent of estimated coal revenues, well below the level 
suggesting that they might have a significant economic impact on a 
substantial number of small entities. Accordingly, MSHA has certified 
that this proposed rule would not have a significant economic impact on 
a substantial number of small entities that are covered by this 
proposed rule.

   Table IX-3.--Estimated Yearly Costs of the Proposed Plan Verification Rule Relative to Yearly Revenues for
                                             Underground Coal Mines
                                             [dollars in thousands]
----------------------------------------------------------------------------------------------------------------
                                                                                    Underground      Costs as
                   Mine size                      PV rule  net yearly costs\a\       coal mine    percentage  of
                                                                                    revenues\b\      revenues
----------------------------------------------------------------------------------------------------------------
< 20 emp......................................  ($685)                                  $201,700             N/A
<=500 emp.....................................  ($2,535)                               5,644,194            N/A
----------------------------------------------------------------------------------------------------------------
\a\ Estimated yearly costs are composed of ``adjusted'' first year costs that have been annualized plus annual
  costs.
\b\ Data for revenues derived from: U.S. Department of Labor, Mine Safety and Health Administration, 2000 PEIR
  data; and U.S. Department of Energy, Energy Information Administration, Coal Industry Annual 2000, January
  2002, p. 206.

X. Other Statutory Requirements

A. Unfunded Mandates Reform Act of 1995

    For purposes of the Unfunded Mandates Reform Act of 1995, this rule 
does not include any Federal mandate that may result in increased 
expenditures by State, local, and tribal governments, or increased 
expenditures by the private sector of more than $100 million.

B. Paperwork Reduction Act of 1995

    The proposed plan verification rule contains information 
collections which are subject to review by the Office of Management and 
Budget (OMB) under the Paperwork Reduction Act of 1995 (PRA95). The 
proposed plan verification rule has first year only burden hours (those 
that occur only in the first year) and annual burden hours (which occur 
in the first year and every year thereafter).
In the First Year of the Plan Verification Proposed Rule
    In the first year the proposed plan verification rule is in effect, 
there would be a net decrease of 34,929 burden hours and a related cost 
reduction of $704,474.
    Table VII-2 in the PREA shows that with respect to first year-only 
burden hours and costs, there would be a net increase of 7,609 burden 
hours and related costs of $371,273. Table VII-2(a) in the PREA shows 
that with respect to every year that the proposed plan verification 
rule is in effect (including the first year), there would be a net 
decrease of 42,538 burden hours and a related cost reduction of 
$1,075,747.
In the Second Year of the Proposed Plan Verification Rule and for Every 
Year Thereafter
    After the first year of the proposed plan verification rule, those 
burden hours and related costs occurring only in the first year would 
no longer occur, and what remains are only the annual burden hours and 
related costs.

[[Page 10861]]

Therefore, in the second year of the proposed plan verification rule 
and for every year thereafter, there would be a net decrease of 42,538 
burden hours and a related cost reduction of $1,075,747.
    We invite public comments and are particularly interested in 
comments which:
    1. Evaluate whether the proposed collection of information 
(presented here and in Chapter 7 of the PREA for the proposed plan 
verification rule) is necessary for the proper performance of the 
functions of MSHA, including whether the information would have 
practical utility;
    2. Evaluate the accuracy of our estimate of the burden of the 
proposed collection of information, including the validity of the 
methodology and assumptions used;
    3. Enhance the quality, utility, and clarity of the information to 
be collected; and
    4. Minimize the burden of the collection of information on 
respondents, including through the use of appropriate automated, 
electronic, mechanical, or other technological collection techniques or 
other forms of information technology, e.g., permitting electronic 
submissions of responses.
    We have submitted a copy of this proposed rule to OMB for its 
review and approval of these information collections. Interested 
persons are requested to send comments regarding this information 
collection, including suggestions for reducing this burden, if under 10 
pages, by facsimile (202) 395-6974 to Attn: Desk Officer for MSHA; or 
by email to: [email protected]. All comments may be sent by mail 
addressed to the Office of Information and Regulatory Affairs, OMB New 
Executive Office Building, 725 17th St., NW., Rm. 10235, Washington, DC 
20503, Attn: Desk Officer for MSHA. Please send a copy of your comments 
to MSHA at the address listed in the ADDRESSES section of the preamble. 
Submit written comments on the information collection not later than 
June 4, 2003.
    Our paperwork submission summarized above is explained in detail in 
Chapter 7 of the PREA. The PREA includes the estimated costs and 
assumptions for each proposed paperwork requirement related to the 
proposed plan verification rule. These paperwork requirements have been 
submitted to the Office of Management and Budget for review under 
section 3504(h) of the Paperwork Reduction Act of 1995. Respondents are 
not required to respond to any collection of information unless it 
displays a current valid OMB control number. The PREA is located on our 
Web site at http://wwww.msha.gov/REGSINFO.HTM.

C. National Environmental Policy Act

    The National Environmental Policy Act (NEPA) of 1969 requires each 
Federal agency to consider the environmental effects of proposed 
actions and to prepare an Environmental Impact Statement on major 
actions significantly affecting the quality of the human environment. 
MSHA has reviewed the proposed standard in accordance with the 
requirements of the NEPA (42 U.S.C. 4321 et seq.), the regulation of 
the Council on Environmental Quality (40 CFR part 1500), and the 
Department of Labor's NEPA procedures (29 CFR part 11). As a result of 
this review, MSHA has preliminarily determined that this proposed 
standard will have no significant environmental impact.
    Commenters are encouraged to submit their comments on this 
determination.

D. Executive Order 12630: Governmental Actions and Interference With 
Constitutionally Protected Property Rights

    This proposed rule is not subject to Executive Order 12630, 
Governmental Actions and Interference with Constitutionally Protected 
Property Rights, because it does not involve implementation of a policy 
with takings implications.

E. Executive Order 12988: Civil Justice Reform

    The Agency has reviewed Executive Order 12988, Civil Justice 
Reform, and determined that this rulemaking will not unduly burden the 
Federal court system. The regulation has been written so as to provide 
a clear legal standard for affected conduct, and has been reviewed 
carefully to eliminate drafting errors and ambiguities.

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

    In accordance with Executive Order 13045, protection of children 
from environmental health risks and safety risks, MSHA has evaluated 
the environmental health or safety effects of the proposed rule on 
children. The Agency has determined that this proposed rule would not 
have an adverse impact on children.

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

    MSHA certifies that this proposed rule does not impose substantial 
direct compliance costs on Indian tribal governments.

H. Executive Order 13132: Federalism

    MSHA has reviewed this rule in accordance with Executive Order 
13132 regarding federalism, and has determined that it does not have 
``federalism implications.'' The rule 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.''

I. Executive Order 13211: Energy

    MSHA has reviewed this proposed rule in accordance with Executive 
Order 13211 regarding the energy effects of Federal regulations and has 
determined that this proposed rule does not have any adverse effects on 
energy supply, distribution, or use. Therefore, no reasonable 
alternatives to this action are necessary.

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

    In accordance with Executive Order 13272, MSHA has thoroughly 
reviewed the Plan Verification proposed rule to assess and take 
appropriate account of its potential impact on small businesses, small 
governmental jurisdictions, and small organizations. As discussed in 
Chapter V of the PREA, MSHA has determined that the proposed rule would 
not have a significant economic impact on a substantial number of small 
entities.

XI. Public Hearings

    MSHA plans to hold public hearings on the proposed rule. The 
hearings will be held under Section 101 of the Federal Mine Safety and 
Health Act of 1977. The hearings will be held in the following cities:
    (a) Evansville, Indiana;
    (b) Charleston, West Virginia;
    (c) Grand Junction, Colorado;
    (d) Birmingham, Alabama;
    (e) Lexington, Kentucky;
    (f) Washington, Pennsylvania, and
    The specific dates, times and facilities for the hearings will be 
announced by a separate notice in the Federal Register.

Appendix A--Derivation of the Critical Values

    All measurements of respirable dust concentration are subject to 
potential sampling and analytical errors. Because of such errors, a 
measurement may fall slightly below the verification limit even when 
the true concentration of

[[Page 10862]]

respirable coal mine dust or respirable quartz dust does not. 
Therefore, to ensure that the verification limits have actually been 
met, it is necessary to provide for a margin of error in each 
measurement. The critical values provide this margin of error. MSHA can 
be confident that the verification limits have not been exceeded at the 
sampled locations. When valid measurements do not exceed the 
appropriate critical values listed in Table 70-1, corresponding to the 
number of shifts sampled.
    To explain how the verification limits were derived, it is helpful 
to define some symbolic notation. Let X represent a measurement, and 
let [mu] represent the true value of whatever quantity is being 
measured i.e., the full-shift average concentration, at a specific 
sampling location, of either respirable coal mine dust or respirable 
quartz dust. The difference between X and [mu] is the measurement error 
and is denoted by [egr] X = [mu] + [egr].
    In accordance with standard statistical and industrial hygiene 
practice, [egr] (but not [mu]) is assumed to be normally distributed. 
Since the approved sampling and analytical methods for measuring 
concentrations of respirable coal mine dust and respirable quartz dust 
are both statistically unbiased, [egr] has a mean value of zero and a 
degree of variability represented by its standard deviation, denoted by 
[sigma] [egr]. The ratio of [sigma][egr] to [mu] is called the 
measurement coefficient of variation (CV) due to sampling and 
analytical errors.\42\ The CV relates entirely to variability due to 
measurement errors and not at all to variability in actual dust 
concentrations.
---------------------------------------------------------------------------

    \42\ In some publications, this ratio is called the relative 
standard deviation (RSD). It is sometimes also denoted by 
CVtotal, where ``total'' refers to all sources of 
potential sampling and analytical error but does not cover 
variability in [mu] itself.
---------------------------------------------------------------------------

    For respirable coal mine dust, the value of CV used in calculating 
critical values was chosen to be consistent with the value proposed at 
[mu] = 2.0 mg/m\3\ in the Notice of Final Policy published in the 
Federal Register: Coal Mine Respirable Dust Standard Noncompliance 
Determinations (63 FR 5700, February 3, 1998):
[GRAPHIC] [TIFF OMITTED] TP06MR03.009

    The 7-percent term in this formula accounts for uncertainty due to 
potential weighing error, and the two 5-percent terms account for 
differences between individual cyclones and for variability in the 
exact volume of air pumped through the filter during a 480-minute 
shift.
    For respirable quartz dust, the value of CV used in calculating 
critical values is:
[GRAPHIC] [TIFF OMITTED] TP06MR03.010

    The 5.3-percent term in this formula accounts for imprecision in 
the Infrared (Infrared Spectrophotometer or IR) measurement of quartz 
mass deposited on the filter, the 4.2-percent term represents 
variability in air volume, and the final 5.6-percent term accounts for 
uncertainty due to variability between individual cyclones, given the 
size distribution of quartz dust encountered in mining environments 
(Bartley, November 1999).
    Each critical value (c) was calculated to provide a confidence 
level of at least 95 percent that the dust control parameters specified 
in the ventilation plan were effective in preventing dust 
concentrations from exceeding the verification limits. Using a 
confidence coefficient of 1.645, based on the standard normal 
probability distribution, knowledge of the CV makes it possible to 
calculate a 1-tailed, 95-percent upper confidence limit (UCL) for [mu], 
given a single measurement X. The UCL is X[middot](1 + 
1.645[middot]CV). When X <= c, the UCL for [mu] is less than or equal 
to the verification limit. When X  c, the UCL for [mu] 
exceeds the verification limit.
    For example, suppose X = 1.71 mg/m\3\ respirable dust. Then the UCL 
for [mu] would be 1.71[middot](1 + (10% of 1.645)) = 1.99 mg/m\3\, 
which is less than the verification limit for respirable coal mine 
dust. If, however, X = 1.72 mg/m\3\, then the UCL for [mu] would be 
1.72[middot]1.1645 mg/m\3\, which slightly exceeds the verification 
limit. Similarly, for respirable quartz dust, the UCL for [mu] is 
87[middot](1 + (9% of 1.645)) = 99.9 [mu]g/m\3\ when X = 87 [mu]g/m\3\ 
and slightly above the verification limit of 100 [mu]g/m\3\ when X = 88 
[mu]g/m\3\.
    If more than one measurement is available, then the confidence 
coefficient changes to reflect multiplication of the tail probabilities 
for independent measurement errors. When n measurements are available, 
the objective is to calculate a critical value (c) such that if each of 
the n measurements is <= c, then the 1-tailed 95-percent UCL for [mu] 
is <= the verification limit. Since the product of the n individual 
tail probabilities must equal 0.05, the appropriate 1-tail probability 
for each measurement individually is the nth root of 0.05.
    For example, if n = 3, then the appropriate 1-tail probability for 
each measurement is the cube root of 0.05, or 0.3684. The standard 
normal confidence coefficient corresponding to this tail probability is 
0.336. Therefore, when all three measurements have the same value (X), 
the UCL is X[middot](1+0.336[middot]CV). Substituting the appropriate 
CV estimate, the UCL is X[middot]1.0336 for respirable coal mine dust 
or X[middot]1.0302 for respirable quartz dust. Consequently, to obtain 
the critical value, the verification limit is first divided by 1.0336 
(coal mine dust) or 1.0302 (quartz dust) and then truncated to the 
desired number of decimal digits. This yields 1.93 mg/m\3\ for coal 
mine dust and 97 [mu]g/m\3\ for respirable quartz dust.
    The confidence coefficients used to establish critical values by 
this method are as follows:

------------------------------------------------------------------------
                                                            Confidence
                            n                               coefficient
------------------------------------------------------------------------
1.......................................................           1.645
2.......................................................           0.760
3.......................................................           0.336
4.......................................................           0.068
------------------------------------------------------------------------

    For n  4, the confidence coefficient is less than 0.068. 
It should be noted that although the critical value calculated for n 
= 4 is slightly below the verification limit for both types 
of respirable dust, for simplicity it was set equal to the verification 
limit as a close approximation.

[[Page 10863]]

Appendix B--Model Powered Air-Purifying Respirator (PAPR) Program

    Note: The following is an example of a Model PAPR Protection 
Program. Not all items contained in this example would be required 
for all mines. Additional items not included in this example might 
be required depending on the conditions at your mine.

1.0 Purpose

    Wellington Mining Company and the Mine Safety and Health 
Administration (MSHA) have determined that, after installing all 
feasible engineering and environmental controls on the 002-0 MMU 
longwall mining section, miners working downwind of the shearer 
continue to be exposed to respirable coal mine dust concentrations in 
excess of the allowable standard during routine mining operations. As a 
result, Wellington Mining Company has been granted permission by MSHA 
to use powered air-purifying respirators to protect affected miners 
from overexposure to this respiratory hazard until such time as other 
feasible engineering controls become available.
    During mining of development entries, Wellington Mining Company, 
for brief periods of time, intermittently encounters high quartz 
concentrations while mining through rock partings. The approved 
ventilation plan parameters likely will not prevent overexposure to 
some miners during these brief occurrences. Accordingly, MSHA has 
approved a revision to the ventilation plan to allow for the use of 
PAPRs, for a period not to exceed 30 days, when these unusual operating 
conditions occur.
    The purpose of this PAPR Protection Program is to specify who is 
required to wear PAPRs and the conditions under which the respirators 
must be used. The miners, occupations, work location or tasks requiring 
PAPR use at Wellington Mining Company are listed in Section 4.0.

2.0 Scope and Application

    This PAPR Protection Program is applicable to all miners who are 
required by the provisions of the approved ventilation plan to wear 
PAPRs. This includes supply and maintenance personnel, electrical crews 
or supervisors working in those areas, occupations or tasks designated 
in Wellington's PAPR Protection Program.
    Miners participating in the PAPR Protection Program do so at no 
cost to them. The expense associated with training, providing and 
maintaining PAPRs will be borne by Wellington Mining Company.

3.0 Responsibilities

Program Administrator

    The Program Administrator is the management official designated by 
Wellington Mining Company who is responsible for administering the PAPR 
Program. The duties of the Program Administrator include:
    [sbull] Selection of the PAPR.
    [sbull] Monitoring respirator use to ensure that PAPRs are used in 
accordance with this program.
    [sbull] Arranging for and conducting training.
    [sbull] Ensuring proper storage and maintenance of PAPRs.
    [sbull] Evaluating the program.
    [sbull] Updating the written programs as needed.
    The Program Administrator for Wellington Mining Company is John 
Doe.

Mine Supervisors

    Mine supervisors are responsible for ensuring that the PAPR 
Protection Program is implemented in their area(s) of responsibility. 
In addition to being knowledgeable about the program requirements for 
their own protection, mine supervisors must also ensure that the 
program is understood and followed by the miners under their 
supervision. Duties of the mine supervisor include:
    [sbull] Ensuring that miners under their supervision have received 
appropriate training.
    [sbull] Ensuring the availability of PAPRs and accessories.
    [sbull] Being aware of miners, areas, occupations or tasks 
requiring the use of PAPRs.
    [sbull] Enforcing the proper use of PAPRs when necessary.
    [sbull] Ensuring that PAPRs are properly cleaned, maintained, and 
stored according to the PAPR Protection Program.
    [sbull] Ensuring that PAPRs fit properly and do not cause 
discomfort.
    [sbull] Coordinating with the Program Administrator on how to 
address respirable coal mine dust hazards or other concerns regarding 
the program.

Miners

    Each miner has the responsibility to wear the PAPR when and where 
required and in the manner in which he or she was trained. Miners must 
also:
    [sbull] Care for their PAPRs as instructed.
    [sbull] Inform their mine supervisor if the PAPR is no longer 
operating properly.
    [sbull] Inform their mine supervisor or the Program Administrator 
of any concerns they have regarding the program.

4.0 Program Elements

Selection Procedures

    The Program Administrator will select the PAPRs to be used on site 
in accordance with all MSHA requirements. The Program Administrator 
will provide all miners who wear PAPRs with a copy of the 
manufacturer's instructions including the use, care, maintenance and 
storage of the PAPR.
    [sbull] PAPRs utilized will be 3M model AS-600LBC, certified by the 
National Institute for Occupational Safety and Health (NIOSH) under 42 
CFR part 84 and approved by MSHA under 30 CFR part 18 and will be used 
in accordance with the terms of certification and approval. The main 
PAPR filter will be the AS-140 HE or equivalent as approved by NIOSH.

PAPR Protection Factor

    The minimum air velocity specified in the approved ventilation plan 
at the headgate of the MMU 002-0 longwall is 550 fpm. Accordingly, the 
assigned protection factor for the use of PAPRs is 2.9.
    When PAPRs are required to be used while mining through rock 
partings on development entries, the air velocity is less than 400 fpm 
which results in an assigned protection factor of 4.0.

PAPR Use

    PAPR protection is required as follows:
    [sbull] For all miners who work or travel downwind of the shearer 
operator when material is being produced on the 002-0 MMU longwall 
section.
    [sbull] For all miners who work or travel on the active production 
face or work or travel downwind of that face when it has been 
determined by mine management that unique operating conditions caused 
by mining through rock partings has or will occur.

General Use Procedures

    [sbull] PAPRs assigned for the exclusive use of a miner will be 
identified by labeling the outside with the miner's full name.
    [sbull] Miners will use PAPRs under conditions specified by the 
program, and in accordance with the training they have received on the 
use of the device. The PAPR will not be used in a manner for which it 
is not certified by NIOSH or approved by MSHA.
    [sbull] All miners should examine the PAPR prior to each shift of 
use for a new main filter, integrity of the visor, and proper 
functioning of the battery and motor assembly.

[[Page 10864]]

Cleaning, Maintenance and Storage

Cleaning
    PAPRs are to be regularly cleaned and disinfected at the designated 
PAPR cleaning station located in the lamproom. Units issued for the 
exclusive use of a miner shall be cleaned prior to use on the next 
shift. Those not assigned for the exclusive use of a miner will be 
cleaned and disinfected prior to the next shift of use or assignment to 
a different miner. All PAPRs will be cleaned by the lamproom attendant.
    The following procedures are to be used when cleaning and 
disinfecting PAPRs:
PAPRs Issued for Exclusive Use
    [sbull] Wipe the Helmet/Headband/Cradle assembly/Head seal/Temple 
seal/visor with a soft cloth dampened with a solution of mild soap and 
water.
    [sbull] Vacuum the motor housing.
    [sbull] Replace the main filter.
    [sbull] Inspect all parts for damage or wear. Replace any parts 
that may affect the performance of the respirator.
    [sbull] All components may be wiped with a soft cloth dampened with 
a solution of disinfectant and water.
PAPRs Not Issued for Exclusive Use
    [sbull] Disassemble the motor housing assembly, the head harness 
assembly, the head seal assembly, the visor assembly, the main filter 
and the expander.
    [sbull] Clean all parts by wiping them with a soft cloth dampened 
with a solution of mild soap and water. Wipe each component with a soft 
cloth dampened with disinfectant.
    [sbull] Allow all parts to dry prior to reinstallation.
    [sbull] Inspect all parts for damage or wear. Replace any parts 
that may affect the performance of the respirator.
    [sbull] Replace the main filter with a new filter.


    Note: The PAPR Program Administrator will ensure an adequate 
supply of appropriate cleaning and disinfection material at the 
cleaning station.

Maintenance

    PAPRs are to be maintained at all times in order to ensure that 
they function properly and adequately protect the miner. Maintenance 
involves a thorough visual inspection for cleanliness, defects and 
operational function. Worn, damaged, defective, or exhausted parts will 
be replaced prior to use. No components will be replaced or repairs 
made beyond those recommended by the manufacturer. All routine 
maintenance will be performed by the lamproom attendant.
    The following checklist will be used when inspecting PAPRs:

[sbull] Headgear
    --Check that there are no dents or cracks in the headgear assembly
    --Look closely at the faceseals. There should be no tears or loss 
of elasticity that could permit contaminated air to enter the headgear.
    --Check that the headseal and temple seals are in good condition.

[sbull] Faceshield
    --Check the faceshield for correct placement in the visor surround. 
Also look for scratches or other visual distortions that make it 
difficult to see through the faceshield.
[sbull] Blower Assembly
    --Remove the blower from the headgear
    --Examine the blower housing and replace it if cracked or damaged.
    --Examine the inside of the blower intake manifold for accumulated 
dust. Clean as described above, if required.

[sbull] Power supply and motor
    --Check operational function
    --Examine for tears or damage to the wiring or cable jacket.
    --Check for compliance with electrical permissibility requirements.

[sbull] PAPR battery packs will be placed on charge if not already 
indicating a full charge.

Storage

    PAPRs will be stored in a clean, dry area, and in accordance with 
the manufacturer's recommendations. Clean/disinfected and inspected 
units will be placed in a sealed plastic bag and stored in the 
lamproom.

Defective PAPRs

    PAPRs that have defective parts shall be removed from service 
immediately. If, during an examination or during the work shift, a 
miner discovers a defect in a PAPR, it should be brought to the 
attention of the supervisor. The supervisor will have the Program 
Administrator or delegate make immediate repairs or secure a 
replacement prior to the miner returning to the work area that requires 
PAPR use. With the approval of the supervisor, miners will be permitted 
to leave the work area to perform limited maintenance on their PAPR in 
a designated area that is free of respirable coal mine dust hazards. 
Situations when this will be permitted include: to wash their PAPR 
facepiece, to replace a filter, leaking hose or exhausted power supply 
(battery), or to repair a damaged/missing visor.

Training

    The Program Administrator will provide training to PAPR users and 
their mine supervisors on the contents of the Wellington Mining 
Company's PAPR Protection Program, on the applicable portions of the 
mine's approved mine ventilation plan revisions, and on MSHA 
respiratory protection standards. Miners will be trained prior to using 
a PAPR in the active workings. Supervisors will also be trained prior 
to using a PAPR in the active workings or prior to supervising miners 
who must wear PAPRs.
    The training course will cover these topics:

[sbull] The Wellington Mining Company's PAPR Protection Program
[sbull] Applicable MSHA standards
[sbull] Respirable coal mine dust (including quartz) hazards 
encountered at Wellington Mining Company's operations and their health 
effects.
[sbull] Limitations of PAPRs
[sbull] PAPR donning, doffing and user fit check
    Miners will be retrained at least annually. Miners must demonstrate 
their understanding of the topics covered in the training through 
hands-on exercises. PAPR training will be documented by the Program 
Administrator.

5.0 Program Evaluation

    The Program Administrator will conduct periodic evaluations of the 
active workings to ensure that the provisions of the program are being 
implemented. The evaluations will include regular consultations with 
miners who use PAPRs and their supervisors, site inspections, an 
examination of respirable coal mine dust sampling results, and a review 
of training records.

6.0 Documentation and Recordkeeping

    A written copy of this program and the MSHA requirements will be 
posted on the mine bulletin board for the review by interested miners, 
and a copy will be kept in the Program Administrator's office.
    Also maintained in the Program Administrator's office are copies of 
training records. Those records will be updated as new miners are 
trained, and as existing miners receive annual refresher training.

[[Page 10865]]

Appendix C--Citation Threshold Values (CTV)

I. Interpretation of the CTV Table

    Each CTV was calculated to ensure that, if the CTV is met or 
exceeded, noncompliance with the applicable dust standard can be 
inferred with at least 95-percent confidence. It is assumed that 
whatever applicable dust standard happens to be in effect at the 
sampling location is binding, and that a citation is warranted whenever 
there is sufficient evidence that an established standard has been 
exceeded. The CTV table does not depend on how the applicable dust 
standard was established, or on any measurement uncertainties in the 
process of setting the applicable dust standard.
    The CTV table provides criteria for testing a tentative, or 
presumptive, hypothesis that the true single-shift average dust 
concentration did not exceed the applicable dust standard (S) at each 
of the individual locations sampled during a particular shift. For 
purposes of this test, the mine atmosphere at each such location is 
presumed to be in compliance unless the corresponding single-shift 
measurement provides sufficient evidence to the contrary. The ``true 
single-shift average'' does not refer, in this context, to an average 
across different occupations, locations, or shifts. Instead, it refers 
entirely to the dust concentration at the specific location of the 
sampler unit, averaged over the course of the particular shift during 
which the measurement was obtained. The CTV table is not designed to 
estimate or test the average dust concentration across occupational 
locations, or within any zone or mine area, or in the air actually 
inhaled by any particular miner.
    The CTV table ensures that noncompliance is cited only when there 
is a 95-percent level of confidence that the applicable dust standard 
has actually been exceeded. A single-shift measurement that does not 
exceed the applicable CTV value, does not necessarily imply probable 
compliance with the applicable dust standard--let alone compliance at a 
95-percent confidence level. For example, a single-shift measurement of 
2.14 mg/m3 would not, according to the CTV table, indicate 
noncompliance with sufficient confidence to warrant a citation if S = 
2.0 mg/m3. This does not imply that the mine atmosphere was 
in compliance on the shift and at the location sampled. On the 
contrary, unless contradictory evidence were available, this 
measurement would indicate that the MMU was probably out of compliance. 
However, because there is a small chance that the measurement exceeded 
the standard only because of measurement error, a citation would not be 
issued. Additional measurements would be necessary to verify the 
apparent lack of adequate control measures. Similarly, a single-shift 
measurement of 1.92 mg/m3 would not warrant citation; but, 
because of possible measurement error, neither would it warrant 
concluding that the mine atmosphere sampled was in compliance. To 
confirm that control measures are adequate, it would be necessary to 
obtain additional measurements.
    Furthermore, even if a single-shift measurement were to 
demonstrate, at a high confidence level, that the mine atmosphere was 
in compliance at the sampling location on a given shift, additional 
measurements would be required to demonstrate compliance on each shift. 
For example, if S = 2.0 mg/m3, then a valid measurement of 
1.65 mg/m3 would demonstrate compliance on the particular 
shift and at the particular location sampled. It would not, however, 
demonstrate compliance on other shifts or at other locations.

II. Derivation of the CTV Table

    To understand how the CTVs are derived and justified, it is first 
necessary to distinguish between variability due to measurement error 
and variability due to actual differences in dust concentration. The 
variability observed among individual measurements obtained at 
different locations (or at different times) combines both: dust 
concentration measurements vary partly because of measurement error and 
partly because of genuine differences in the dust concentration being 
measured. This distinction, between measurement error and variation in 
the true dust concentration, can more easily be explained by first 
carefully defining some notational abbreviations.
    One or more dust samples are collected in the same MMU or other 
mine area on a particular shift. Since it is necessary to distinguish 
between different samples in the same MMU, let Xi represent 
the MRE-equivalent dust concentration measurement obtained from the 
ith sample. The quantity being measured is the true, single-
shift average dust concentration at the ith sampling 
location and is denoted by [mu]i. Because of potential 
measurement errors, [mu]i can never be known with complete 
certainty. A ``sample,'' ``measurement,'' or ``observation'' always 
refers to an instance of Xi rather than [mu]i.
    The overall measurement error associated with an individual 
measurement is nothing more than the difference between the measurement 
(Xi) and the quantity being measured ([mu]i). 
Therefore, this error can be represented as

[egr]i = Xi - [mu]i.

    Equivalently, any measurement can be regarded as the true 
concentration in the atmosphere sampled, with a measurement error added 
on:

Xi = [mu]i + [egr]i.

    For two different measurements (X1 and X2), 
it follows that X1 may differ from X2 not only 
because of the combined effects of [egr]1 and 
[egr]2, but also because [mu]1 differs from 
[mu]2.
    The probability distribution of Xi around 
[mu]i depends only on the probability distribution of 
[egr]i and should not be confused with the statistical 
distribution of [mu]i itself, which arises from spatial and/
or temporal variability in dust concentration. This variability (i.e., 
among [mu]i for different values of I) is not associated 
with inadequacies of the measurement system, but real variation in 
exposures due to the fact that contaminant generation rates vary 
greatly in time and contaminants are heterogeneously distributed in 
workplace air.
    Since noncompliance determinations are made relative to individual 
sampling locations on individual shifts, derivation of the CTV table 
requires no assumptions or inferences about the spatial or temporal 
pattern of atmospheric dust concentrations--i.e., the statistical 
distribution of [mu]i. MSHA is not evaluating dust 
concentrations averaged across the various sampler locations. 
Therefore, the degree and pattern of variability observed among 
different measurements obtained during MSHA sampling are not used in 
establishing any CTV. Instead, the CTV for each applicable dust 
standard (S) is based entirely on the distribution of measurement 
errors ([egr]i) expected for the maximum dust concentration 
in compliance with that standard--i.e., a concentration equal to S 
itself.
    If control filters are used to eliminate potential biases, then 
each [egr]i arises from a combination of four weighing 
errors (pre- and post-exposure for both the control and exposed filter 
capsule) and a continuous summation of instantaneous measurement errors 
accumulated over the course of an eight-hour sample. Since the eight-
hour period can be subdivided into an arbitrarily large number of sub-
intervals, and some fraction of [egr]i is associated with 
each sub-interval, [egr]i can be represented as comprising 
the sum of an

[[Page 10866]]

arbitrarily large number of sub-interval errors. By the Central Limit 
Theorem, such a summation tends to be normally distributed, regardless 
of the distribution of sub-interval errors. This does not depend on the 
distribution of [mu]i, which is generally represented as 
being lognormal.
    Furthermore, each measurement made by MSHA personnel is based on 
the difference between pre- and post-exposure weights of a dust sample, 
as determined in the same laboratory, and adjusted by the weight gain 
or loss of the control filter capsule. Any systematic error or bias in 
the weighing process attributable to the laboratory is mathematically 
canceled out by subtraction. Furthermore, any bias that may be 
associated with day-to-day changes in laboratory conditions or 
introduced during storage and handling of the filter capsules is also 
mathematically canceled out. Elimination of the sources of systematic 
errors identified above, together with the fact that the concentration 
of respirable dust is defined by section 202(e) of the Mine Act to mean 
the average concentration of respirable dust measured by an approved 
sampler unit, implies that the measurements are unbiased. This means 
that [egr]i is equally likely to be positive or negative 
and, on average, equal to zero.
    Therefore, each [egr]i is assumed to be normally 
distributed, with a mean value of zero and a degree of variability 
represented by its standard deviation
[GRAPHIC] [TIFF OMITTED] TP06MR03.011

    Since Xi = [mu]i + [egr]i, it 
follows that for a given value of [mu]i, Xi is 
normally distributed with expected value equal to [mu]i and 
standard deviation equal to [sigma]i. CVtotal, is 
the coefficient of variation in measurements corresponding to a given 
value of [mu]i. CVtotal relates entirely to 
variability due to measurement errors and not at all to variability in 
actual dust concentrations.
    MSHA's procedure for citing noncompliance based on the CTV table 
consists of formally testing a presumption of compliance at every 
location sampled. Compliance with the applicable dust standard at the 
ith sampling location is expressed by the relation [mu]i <= 
S. Max{[mu]i{time}  denotes the maximum dust concentration, 
among all of the sampling locations within a MMU. Therefore, if 
Max{[mu]i{time}  <= S, none of the sampler units in the MMU 
were exposed to excessive dust concentration. Since the burden of proof 
is on MSHA to demonstrate noncompliance, the hypothesis being tested 
(called the null hypothesis, or H0,) is that the 
concentration at every location sampled is in compliance with the 
applicable dust standard. Equivalently, for a MMU the null hypothesis 
(H0) is that max{[mu]i{time}  <= S. In other 
areas, where only one, full-shift measurement is made, the null 
hypothesis is simply that [mu]i <= S.
    The test consists of evaluating the likelihood of measurements 
obtained during an MSHA sample, under the assumption that H0 
is true. Since Xi = [mu]i + [egr]i, 
Xi (or max{Xi{time}  in the case of a MMU) can 
exceed S even under that assumption. However, based on the normal 
distribution of measurement errors, it is possible to calculate the 
probability that a measurement error would be large enough to fully 
account for the measurement's exceeding the standard. The greater the 
amount by which Xi exceeds S, the less likely it is that 
this would be due to measurement error alone. If, under H0, 
this probability is less than five percent, then H0 can be 
rejected at a 95-percent confidence level and a citation is warranted. 
For a MMU, rejecting H0 (and therefore issuing a citation) 
is equivalent to determining that [mu]i  S for at 
least one value of I.
    Each CTV listed was calculated to ensure that citations will be 
issued at a confidence level of at least 95 percent. As described in 
MSHA's February 1994 notice and explained further by Kogut [2], the 
tabled CTV corresponding to each S was calculated on the assumption 
that, at each sampling location:
[GRAPHIC] [TIFF OMITTED] TP06MR03.012

    The MSHA and NIOSH joint finding establishes that for valid 
measurements made with an approved sampler unit, CVtotal is 
in fact less than CVCTV at all dust concentrations 
([mu]i).
    The situation in which measurement error is most likely to cause an 
erroneous noncompliance determination is the hypothetical case of 
[mu]i = S for either a single-shift sample measurement or 
for all of the measurements made in the same MMU. In that borderline 
situation--i.e., the worst case consistent with H0--the 
standard deviation is identical for all measurement errors. Therefore, 
the value of [sigma] used in constructing the CTV table is the product 
of S and CVCTV evaluated for a dust concentration equal to 
S:
[GRAPHIC] [TIFF OMITTED] TP06MR03.013

    Assuming a normal distribution of measurement errors as explained 
above, it follows that the probability a single measurement would equal 
or exceed the critical value
[GRAPHIC] [TIFF OMITTED] TP06MR03.020

is five percent under H0 when CVtotal = 
CVCTV. The tabled CTV corresponding to S is derived by 
simply raising the critical value c up to the next exact multiple of 
0.01 mg/m\3\.
    For example, at a dust concentration ([mu]i) just 
meeting the applicable dust standard of S = 2 mg/m\3\, CVCTV 
is 9.95 percent. Therefore, the calculated value of c is 2.326 and the 
CTV is 2.33 mg/m\3\. Any valid single-shift measurement at or above 
this CTV is unlikely to be this large simply because of measurement 
error. Therefore, any such measurement warrants a noncompliance 
citation.
    The probability that a measurement exceeds the CTV is even smaller 
if [mu]i < S for any I. Furthermore, to the extent that 
CVtotal is actually less than CVCTV, [sigma] is 
actually less than S[middot]CVCTV. This results in an even 
lower probability that the critical value would be exceeded under the 
null hypothesis. Consequently, if any single-shift measurement equals 
or exceeds c, then H0 can be rejected at confidence level of 
at least 95-percent. Since rejection of H0 implies that 
[mu]i  S for at least one value of I, this 
warrants a noncompliance citation.
    It should be noted that when each of several measurements is 
separately compared to the CTV table, the probability that at least one 
[egr]i will be large enough to force Xi 
= CTV when [mu]i <= S is greater than the 
probability when only a single comparison is made. For example (still 
assuming S = 2 mg/m3), if CVtotal is actually 
6.6%, then the standard deviation of [egr]i is 6.6% of 2.0 
mg/m3, or 0.132 mg/m3, when [mu]i = S. 
Using properties of the normal

[[Page 10867]]

distribution, the probability that any single measurement would exceed 
the CTV in this borderline situation is calculated to be 0.0062. 
However, the probability that at least one of five such measurements 
results in a citation is 1 - (0.9938)5 = 3.1 percent. 
Therefore, the confidence level at which a citation can be issued, 
based on the maximum of five measurements made in the same MMU on a 
given shift, is 97%.
    The constant 1.64 used in calculating the CTV is a 1-tailed 95-
percent confidence coefficient and is derived from the standard normal 
probability distribution. Since the purpose of the CTV table is to 
provide criteria for determining that the true dust concentration 
strictly exceeds the applicable dust standard and such a determination 
can occur only when a single-shift measurement is sufficiently high, 
there is exactly zero probability of erroneously citing noncompliance 
when a measurement falls below the lower confidence limit. 
Consequently, the total probability of erroneously citing noncompliance 
equals the probability that a standard normal random variable exceeds 
1.64, which is 5 percent.

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129-135, 1996.

Appendix E--Supplemental References

    The following references have been added to the Single Sample 
rulemaking record.
    3M AirstreamTM High Efficiency Headgear Systems: User 
Instructions for: AS-200LBC, AS-400LBC, AS-600LBC, 3M Occupational 
Health and Environmental Safety Division, January 1999.
    3M AirstreamTM High Efficiency Headgear Systems: New 
Parts Insert
    3M AirstreamTM Powered Air Purifying Respirator High 
Efficiency Headgear: Number 4046, Occupational Health and Environmental 
Safety Division, Issue Date 9/01/01.
    3M AirstreamTM High Efficiency Helmet, User 
Instructions, January 21, 1999.
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Meretricious Effects of Coal Dust [letter]. (See Beeckman-Wagner et 
al., 2002 for authors' response). AM J Respir Crit Care, Feb 15; 
165(4):552-43, 2002.
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J.E. Parker, Surveillance of pneumoconiosis morbidity in U.S. 
underground coal miners: 1975-1995. 1998 Elsevier Sciences BV. Advances 
in the Prevention of Occupational Respiratory Diseases. K. Chiyotani, 
Y. Hosoda and Y. Aizawa, editors.
    American Industrial Hygiene Association, American National Standard 
for Color Coding of Air-Purifying Respirator Canisters, Cartridges, and 
Filters, ANSI/AIHA Z88.7-2001.
    American National Standards Institute, American National Standard 
for Respiratory Protection, ANSI Z88.2-1992.
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Appearances of Small Opacities and their Correlation with Pathology 
Grading of Macules, Nodules and Dust Burden in the Lungs. Ann. Occup. 
Hyg., Volume 38, Supplement I:783-789, 1994.
    Beeckman-Wagner, L.F.; Wang, M.; Petsonk, E. and G.R. Wagner. 
Meretricious effects of coal dust [authors' response]. American Journal 
of Respiratory Critical Care Medicine. February 15; 165(4):553, 2002.
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Declines in FEV1 and Subsequent Respiratory Symptoms, 
Illnesses, and Mortality in Coal Miners in the United States. American 
Journal of Respiratory Critical Care Medicine. Vol 163:633-639, 2001.

[[Page 10872]]

    Bureau of Labor Statistics, U.S. Department of Labor. Respirator 
Use and Practices. Press Release USDL 02-141, March 20, 2002.
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Pneumoconiosis, Environmental Health Perspectives, Vol 108, Supplement 
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Department of Labor, Occupational Safety and Health Administration, The 
Workplace Performance of a Loose-Fitting Facepiece Powered Air-
Purifying Respirator with High Efficiency Filters. Prepared for 
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Conference and Exposition, Orlando Florida.
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exposure, dust recovered from the lung, and associated pathology in a 
group of British coalminers. British Journal of Industrial Medicine. 
43:795-801, 1986.
    Fernie, J.M. and V.A. Ruckley, Coalworkers' pneumoconiosis: 
correlation between opacity profusion and number and type of dust 
lesions with special reference to opacity type. British Journal of 
Industrial Medicine, 44:273-277, 1987.
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the Study of Chronic Occupational Lung Disease: A Comparison of 
Different Exposure Assessment Strategies. American Journal of 
Epidemiology, 151:(10):982-990, 2000.
    Jimenez-Ruiz, C.A., Masa, F.; Miravitlles, M., Gabriel, R.; Vieho, 
J.L.; Villsante, C.; Sobradillo, V.; and the IBERPOC Study 
Investigators, Smoking Characteristics: Differences in Attitudes and 
Dependence Between Healthy Smokers and Smokers with COPD. Chest, 
119:(5):1365-1370, May 2001.
    Kuempel, E.D.; O'Flaherty, E.J.; Stayner, L.T.; Smith, R.J.; Green, 
F.H.Y.; and V. Vallyathan. A Biomathematical Model of Particle 
Clearance and Retention in the Lungs of Coal Miners. Regulatory 
Toxicology and Pharmacology, 34:69-87, 2001.
    Kuempel, E.D.; Tran, C.; Smith, R.; and A.J. Bailer. A 
Biomathematical Model of Particle Clearance and Retention in the Lungs 
of Coal Miners. Regulatory Toxicology and Pharmacology, 34:88-101, 
2001.
    Li, H.; Wang, M.; Seixas, N.; Ducatman, A.; and E.L. Petsonk. 
Respiratory Protection: Associated Factors and Effectiveness of 
Respirator Use Among Underground Coal Miners. American Journal of 
Industrial Medicine, 42:55-62, 2002.
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Workers with Simple Pneumoconiosis: Early Detection of Functional 
Abnormalities. Kaohsiung J Med Sci. 17(5):245-52, May 2001.
    Meyer, J.D.; Holt, D.L.; Chen, Y.; Cherry, N.M.; and J.C. McDonald. 
SWORD '99: surveillance of work-related and occupational respiratory 
disease in the UK. Occup Med (Lond), 51(3):204-208, May 2001.
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Coal General Inspection Procedures Handbook, Chapter 5, Release 1 (June 
1992).
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Safety and Health Administration, dated September 30, 2002, correcting 
a July 11, 2002 letter from Dr. Gregory R. Wagner to Ms. Pon, Re: 
CWXSP.
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Test for PAPR, Task Number: TN-11893, Reference No.: CFR 84.1157, April 
17, 2001.
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Relationship Among Coal Rank, Airborne Dust, and Incidence of Workers' 
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Health Administration, Subject: 2001 OWCP Report Statistics, September 
11, 2002.
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Statistician, Employment Standards Administration, DOL, to William 
Baughman, Standards and Variances Specialist, Mine Safety and Health 
Administration, Subject: Black Lung Program Statistics.
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Administration, Subject: Draft. Tables Associated with the 2001 OWCP 
Annual Report.
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lung disease. Curr Opin Pulm Med. 8(2):117-125, March 2002.
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Respirator (PAPR) with High-Efficiency Particulate Air (HE) Filter, 
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526000. July 1992/April 1996.
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2000.
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March 2001.

XII. Regulatory Text

List of Subjects

30 CFR Part 70

    Coal, Mine safety and health, Underground coal mines, Respirable 
dust.

30 CFR Part 75

    Coal, Mine safety and health, Underground coal mines, Ventilation.

30 CFR Part 90

    Coal, Mine safety and health.

    Dated: February 12, 2003.
Dave D. Lauriski,
Assistant Secretary of Labor for Mine Safety and Health.

    Accordingly, MSHA proposes to amend Chapter I of Title 30 of the 
Code of Federal Regulations as follows:

[[Page 10873]]

PART 70--MANDATORY HEALTH STANDARDS--UNDERGROUND COAL MINES

    1. The authority citation for part 70 is revised to read as 
follows:

    Authority: 30 U.S.C. 811, 813(h), 957 and 961.

    2. Subpart A is revised to read as follows:

Subpart A--General

Sec.
70.1 Scope.
70.2 Definitions.


Sec.  70.1  Scope and purpose.

    This part sets forth mandatory health standards for each 
underground coal mine subject to the Federal Mine Safety and Health Act 
of 1977.


Sec.  70.2  Definitions.

    Act. The Federal Mine Safety and Health Act of 1977, Public Law 91-
173, as amended by Public Law 95-164, 30 U.S.C. 801 et seq.
    Active workings. Any place in a coal mine where miners are normally 
required to work or travel.
    Administrative controls. Methods of controlling the respirable dust 
exposure of an individual miner assigned to a specific work position or 
occupation by job rotation, altering the way in which the assigned work 
is performed, providing time periods away from dust-generating sources. 
These procedures must be:
    (1) Capable of being reviewed to confirm their proper 
implementation,
    (2) Clearly understood by the affected miners, and
    (3) Applied consistently over time.
    Approved sampling device. A sampling device of the constant-flow 
type:
    (1) Approved by the Secretary and the Secretary of Health and Human 
Services under part 74 of this title; or
    (2) Approved by the Secretary when it has been determined that the 
measured concentration of respirable dust can be converted to an 
equivalent concentration as measured with a sampling device approved 
under part 74 of this title.
    Certified person. An individual certified by the Secretary to take 
respirable dust samples and/or to perform the maintenance and 
calibration of approved sampling devices.
    Citation threshold value (CTV). The lowest equivalent concentration 
measurement demonstrating that the applicable dust standard has been 
exceeded at a confidence level of at least 95 percent.
    Concentration. The amount of respirable dust contained per unit 
volume of air.
    Control filter. An unexposed filter cassette of the same design and 
material as the filter cassette used for sampling that is pre- and 
post-weighed on the same day as the exposed filters.
    Critical value. The highest equivalent concentration measurement 
demonstrating that the applicable verification limit has been met at a 
confidence level of at least 95 percent.
    Designated area (DA). An area of a mine identified by the operator 
under Sec.  75.371(t) of this title and approved by the district 
manager, or identified by the Secretary. Each DA is identified by a 
four-digit identification number assigned by MSHA.
    Designated occupation (DO). The occupation or work location on a 
mechanized mining unit that has been determined by results of 
respirable dust samples to exhibit the greatest respirable dust 
concentration.
    District manager. The manager of the Coal Mine Safety and Health 
District in which the mine is located.
    Dust control parameters. Specific engineering or environmental 
controls, maintenance procedures, and other measures specified in the 
approved mine ventilation plan for controlling respirable dust in the 
mine atmosphere of the active workings.
    Engineering or environmental controls. Methods of controlling the 
level of respirable dust by reducing the quantity released into the 
work environment, by diluting, capturing or diverting the generated 
dust.
    Equivalent concentration. The concentration of respirable coal mine 
dust, as measured by an approved sampling device, converted to an MRE 
8-hour equivalent as follows:
    (1) Multiply the concentration measured by the approved sampling 
device by the constant factor prescribed by the Secretary for that 
device and then apply criteria in paragraphs (2) and (3) of this 
definition if applicable.
    (2) If the sampled shift is longer than 8 hours, multiply the 
concentration obtained in paragraph (1) of this definition by t/480 
where t is the length of the sampled work shift in minutes.
    (3) If using PAPRs, divide the concentration obtained in paragraph 
(1) or (2) of this definition (whichever is applicable) by the 
protection factor assigned to the mechanized mining unit.
    Material produced. Coal and/or any other substance(s) extracted by 
a mechanized mining unit during any production shift.
    Mechanized mining unit (MMU). A set of mining equipment, including 
hand loading equipment, used for the production of material; or a 
specialized set which utilizes mining equipment other than specified in 
Sec.  70.206(d) for the production of material. Each MMU is assigned a 
four-digit identification number by MSHA. The identification number is 
retained by the MMU regardless of where the unit relocates within the 
mine. When two sets of mining equipment are provided in a series of 
working places and only one production crew is employed at any given 
time on either set of mining equipment, the two sets of equipment are 
identified as a single MMU. When two or more sets of mining equipment 
are simultaneously engaged in the production of material within the 
same working section, each such mechanized mining unit is identified 
separately.
    MRE. The Mining Research Establishment of the National Coal Board, 
London, England.
    MRE instrument. A gravimetric dust sampler with a four channel 
horizontal elutriator developed by the MRE.
    MSHA. The Mine Safety and Health Administration of the Department 
of Labor.
    Personal continuous dust monitor (PCDM). An instrument that 
monitors the concentration of respirable dust on a continuous basis and 
displays in real-time the measured dust exposure information.
    Powered air-purifying respirator (PAPR). A type of air-purifying 
respirator that uses a blower to force ambient air through the air-
purifying elements to the inlet covering (a visor), which forms a 
partial seal with the face, to deliver filtered air into the miner's 
breathing area.
    Protection factor (PF). A measure of the level of respiratory 
protection that would be expected in the workplace from a properly 
functioning PAPR when correctly worn and used. The protection factor is 
the ratio of the respirable dust concentration outside the respirator 
facepiece to the concentration inside the facepiece. For MMUs with 
average air velocity in the working face:
    (1) <400 feet per minute (fpm), PF = 4;
    (2) 800 fpm, PF = 2; and
    (3) between 400 fpm and 800 fpm, the applicable PF is determined by 
the following formula: 2 x (800 fpm/actual air velocity).
    Production shift.
    (1) With regard to a MMU, a shift during which material is 
produced; or
    (2) With regard to a DA, a shift during which material is produced 
and routine day-to-day activities occur in the DA.
    Quartz. Crystalline silicon dioxide (SiO2) as measured 
by:

[[Page 10874]]

    (1) MSHA's Analytical Method P-7: Infrared Determination of Quartz 
in Respirable Coal Mine Dust; or
    (2) any method approved by MSHA as providing a measurement of 
quartz equivalent to that measured by Analytical Method P-7.
    Respirable dust. Dust collected with an approved sampling device.
    Secretary. The Secretary of Labor or delegate.
    Valid sample. A respirable dust sample collected and submitted as 
required by this part, and not voided by MSHA.
    Verification limits. 2.0 mg/m3 of respirable coal mine 
dust and 100 [mu] g/m3 of respirable quartz dust, each 
expressed as an equivalent concentration.
    Verification production level (VPL). The tenth highest production 
level recorded in the most recent 30 production shifts; or, if fewer 
than 30 shifts of production data are available, the minimum production 
level attained on any shift used to verify the adequacy of the dust 
control parameters.
    Working face. Any place in a coal mine in which work of extracting 
coal from its natural deposit in the earth is performed during the 
mining cycle.
    3. Subpart B is revised to read as follows:

Subpart B--Dust Standards

Sec.
Sec.  70.100 Respirable dust standards when quartz is not present.
Sec.  70.101 Respirable dust standard when quartz is present.


Sec.  70.100  Respirable dust standard when quartz is not present.

    (a) Each operator must continuously maintain the average 
concentration of respirable dust in the mine atmosphere during each 
shift to which each miner in the active workings of each mine is 
exposed at or below 2.0 milligrams per cubic meter of air (mg/
m3) as measured with an approved sampling device and in 
terms of an equivalent concentration determined in accordance with 
Sec.  70.2.
    (b) Each operator must continuously maintain the average 
concentration of respirable dust within 200 feet outby the working 
faces of each section in the intake airways at or below 1.0 mg/
m3 as measured with an approved sampling device and in terms 
of an equivalent concentration determined in accordance with Sec.  
70.2.


Sec.  70.101  Respirable dust standard when quartz is present.

    When the respirable dust contains more than five percent quartz, as 
determined by the average of the most recent three MSHA samples, the 
operator must continuously maintain the average concentration of 
respirable dust in the mine atmosphere during each shift in the active 
workings of each mine, as measured with an approved sampling device and 
in terms of an equivalent concentration determined in accordance with 
Sec.  70.2, at or below the applicable dust standard. The applicable 
dust standard is determined by dividing the average quartz percentage 
into the number 10.

    Example: Assume a MMU or a DA is on a 2.0-mg/m3 dust 
standard (5% or less). If the first MSHA sample contains 7.2% of 
quartz, and the required two subsequent samples contained 9.5% and 
10.6%, respectively, the average quartz percentage would be 9.1% 
[(7.2% + 9.5% + 10.6%)/3 = 9.1%]. Therefore, the equivalent 
concentration of respirable dust in the mine atmosphere associated 
with that MMU or DA must, on each shift, be maintained at or below 
1.1 mg/m3 [10/9.1% = 1.1 mg/m3].

    4. Subpart C is revised to read as follows:

Subpart C--Sampling Procedures

Sec.
70.201 Sampling; general and technical requirements.
70.202 Approved sampling devices; maintenance and calibration.
70.203 Approved sampling devices; operation; air flowrate.
70.204 Demonstrating the adequacy of the dust control parameters 
specified in a mine ventilation plan; verification sampling.
70.205 Verification sampling; when required; time for completing.
70.206 Verification sampling; procedures for sampling.
70.207 Approval of dust control parameters by district manager; 
revocation of approval.
70.208 Follow-up action when either verification limit is exceeded.
70.209 Use of supplementary control measures; types and conditions 
for use; request for approval.
70.210 Powered air-purifying respirators (PAPRs); requirements for 
approval.
70.211 Powered air-purifying respirators (PAPRs); approval and 
conditions for continued use; revocation of approval.
70.212 Powered air-purifying respirators (PAPRs); conditions of use 
under special circumstances.
70.213 Administrative controls; requirements for approval.
70.214 Administrative controls; approval and conditions for 
continued use; revocation of approval.
70.215 Quarterly evaluation of approved plan parameters.
70.216 Respirable dust samples; transmission by operator.
70.217 Respirable dust samples; report to operator; and posting.
70.218 Violation of respirable dust standard; issuance of citation; 
action required by operator; and termination of citation.
70.219 Status change reports.
70.220 Personal continuous dust monitor (PCDM).


Sec.  70.201  Sampling; general and technical requirements.

    (a) Each operator must conduct respirable dust sampling required by 
this part with an approved sampling device.
    (b) Sampling must be performed by a certified person. To be 
certified, a person must pass the MSHA examination on sampling of 
respirable coal mine dust.
    (c) Sampling devices must be worn or carried directly to and from 
the MMU to be sampled and must be operated in accordance with the 
requirements of this part.
    (d) Except as provided in paragraph (h) of this section, one 
control filter must be used for each shift of sampling. Each control 
filter must have the same preweight date (noted on the dust data card) 
as the ones that are used for sampling; must remain plugged at all 
times; must be exposed to the same time, temperature, and handling 
conditions as the ones used for sampling; and must be kept with the 
exposed samples after sampling.
    (e) Except as provided in paragraph (i) of this section, sampling 
must be conducted on a shift during which the amount of material 
produced by the MMU is at or above the verification production level 
(VPL), as defined in Sec.  70.2, and using only the dust control 
parameters listed in the approved mine ventilation plan, at levels not 
exceeding 115 percent of the specified quantities.
    (1) If the VPL is not achieved, the samples for that shift will be 
voided by MSHA. However, any sample, regardless of production, that 
exceeds either verification limit or applicable dust standard will be 
used to determine the equivalent concentration for that occupation.
    (2) If the MMU being evaluated is authorized to use PAPRs under 
special circumstances (see Sec.  70.212) and those circumstances 
prevent the operator from achieving the VPL, the sample(s) for that 
shift will be used to determine the equivalent concentration for the 
affected occupations.
    (f) Each operator must provide affected miners and their 
representatives with an opportunity to observe respirable dust sampling 
required by this part and must give prior notice of the date and time 
of intended sampling to affected miners and their representatives. An 
operator is exempt from this requirement if using personal

[[Page 10875]]

continuous dust monitors in accordance with Sec.  70.220.
    (g) Upon request from the district manager, the operator must 
submit the date and time when any sampling required by this part will 
begin.
    (h) Paragraph (d) of this section does not apply if sampling to 
conform with the requirements of Sec.  70.215 or Sec.  70.220(d).
    (i) Paragraph (e) of this section does not apply if sampling to 
conform with the requirements of Sec.  70.220(d).


Sec.  70.202  Approved sampling devices; maintenance and calibration.

    (a) Sampling devices must be maintained as approved and calibrated 
by a certified person in accordance with MSHA Informational Report IR 
1240 (1996) ``Calibration and Maintenance Procedures for Coal Mine 
Respirable Dust Samplers (supersedes IR 1121)'' or in accordance with 
the manufacturer's specifications if using a personal continuous dust 
monitor (PCDM) under Sec.  70.220. To be certified, a person must pass 
the MSHA examination on maintenance and calibration for approved 
sampling devices.
    (b) Sampling devices must be calibrated at the flowrate of 2.0 
liters of air per minute, or at a different flowrate as prescribed by 
the Secretary and the Secretary of Health and Human Services for the 
particular device, before they are put into service and, thereafter, at 
time intervals prescribed by the manufacturer.
    (c) If equipped with a flowmeter, a calibration mark must be placed 
on the flowmeter of each sampling device to indicate the proper 
position of the float when the sampler is operating at a flowrate of 
2.0 liters of air per minute or other flowrate prescribed by the 
Secretary and the Secretary of Health and Human Services for the 
particular device. The standard to denote proper flow is when the 
lowest part of the float is lined up with the top of the calibration 
mark.
    (d) Except as provided in paragraph (f) of this section, each 
sampling device must be tested and examined immediately before each 
sampling shift and necessary external maintenance must be performed by 
a certified person to assure that the sampling device is clean and in 
proper working condition. This testing and examination must include the 
following:
    (1) Testing the voltage of each battery while under actual load to 
assure the battery is fully charged. The voltage for nickel cadmium 
cell batteries must not be lower than the product of the number of 
cells in the battery pack multiplied by 1.25. The voltage for other 
than nickel cadmium cell batteries must not be lower than the product 
of the number of cells in the battery pack multiplied by the 
manufacturer's nominal voltage per cell.
    (2) Examination of all components of the cyclone to assure that 
they are clean and free of dust and dirt;
    (3) Examination of the inner surface of the cyclone on the approved 
sampling device to assure that it is free of scoring;
    (4) Examination of the external tubing on the approved sampling 
device to assure that it is clean and free of leaks, and;
    (5) Examination of the clamping and positioning of the cyclone 
body, vortex finder and cassette to assure that they are rigid, in 
alignment, and firmly in contact.
    (e) In accordance with 5 U.S.C. 552(a) and 1 CFR, part 51, MSHA 
Informational Report No. 1240 (1996) referenced in paragraph (a) of 
this section is incorporated-by-reference. Copies may be inspected or 
obtained without charge at each Coal Mine Safety and Health District 
office of MSHA.
    (f) Paragraphs (d)(1) through (d)(5) of this section do not apply 
if using a PCDM. The operator must follow the examination procedures 
recommended by the manufacturer or prescribed by the Secretary and the 
Secretary of Health and Human Services for the particular device.


Sec.  70.203  Approved sampling devices; operation; air flowrate.

    (a) Sampling devices must be operated at the flowrate of 2.0 liters 
of air per minute, or at a different flowrate as prescribed by the 
Secretary and the Secretary of Health and Human Services for the 
particular device.
    (b) Except as provided in paragraphs (c) and (d) of this section, 
each sampling device must be examined each shift by a person certified 
to sample during:
    (1) The second hour after being put into operation to assure that 
the sampling device is operating properly and at the proper flowrate. 
If the proper flowrate is not maintained, necessary adjustments must be 
made by the certified person.
    (2) The last hour of operation to assure that the sampling device 
is operating properly and at the proper flowrate. If the proper 
flowrate is not maintained, the respirable dust sample must be 
transmitted to MSHA with a notation by the certified person on the back 
of the dust data card stating that the proper flowrate was not 
maintained. Also to be noted are any other events occurring during 
sampling that may affect the validity of the sample.
    (c) Paragraph (b)(1) of this section will not apply if the approved 
sampling device is being operated in a breast or chamber of an 
anthracite coal mine where the full box mining method is used.
    (d) Paragraphs (b)(1) and (2) of this section do not apply if using 
a personal continuous dust monitor in accordance with Sec.  70.220. To 
assure that the personal dust monitor is operating properly and at the 
proper flowrate, the operator must follow the procedures recommended by 
the manufacturer or prescribed by the Secretary and the Secretary of 
Health and Human Services for the particular device.


Sec.  70.204  Demonstrating the adequacy of the dust control parameters 
specified in a mine ventilation plan; verification sampling.

    As of ---------- (Insert date which must be within 12 months of the 
effective date of this rule), each operator of an underground coal mine 
must have a ventilation plan in which the dust control parameters 
specified for each MMU have been verified through sampling to be 
adequate in controlling respirable dust as required by Sec.  
75.370(a)(1) of this title. To demonstrate that the plan parameters for 
each MMU are adequate, the operator must show, with a high level of 
confidence, that the equivalent concentration of respirable coal mine 
dust and respirable quartz dust can be maintained at or below the 
verification limits (2.0 mg/m3 and 100 [mu]g/m3, 
respectively) as determined by meeting the critical values in Table 70-
1.


Sec.  70.205  Verification sampling; when required; time for 
completing.

    (a) The operator must, within 45 calendar days after obtaining 
provisional approval, verify the adequacy of the dust control 
parameters for each MMU when:
    (1) Submitting a ventilation plan under Sec.  75.370 for a newly 
established MMU.
    (2) The district manager determines that the previously approved 
plan parameters are inadequate to control respirable dust under the 
prevailing operating conditions and requires the operator to revise the 
plan parameters.
    (b) The district manager may, upon written request, grant the 
operator an extension of up to 30 calendar days to complete 
verification sampling.
    (c) All previously approved ventilation plans must be revised in 
accordance with Sec.  75.371(f) of this title and the adequacy of the 
dust control parameters verified by ---------- (Insert date which must 
be within 12 months of the effective date of this rule.)

[[Page 10876]]

Sec.  70.206  Verification sampling; procedures for sampling.

    (a) Each operator must sample the following occupations for each 
MMU:
    (1) Designated occupation (DO);
    (2) Roof bolter operator(s);
    (3) Longwall jack setters; and
    (4) Any other occupation designated by the district manager.
    (b) Each sampling device must be turned ``ON'' upon arriving at the 
MMU to be sampled, must remain operational the entire period spent in 
the MMU, and must be turned ``OFF'' at the end of the shift as the 
device exits the MMU.
    (c) Multiple-shift samples are not required to be collected on 
consecutive shifts. All samples collected during verification sampling 
must be submitted to MSHA.
    (d) Unless otherwise directed by the district manager, the DO 
samples must be collected by placing the sampling device as follows:
    (1) Conventional section using cutting machine--on the cutting 
machine operator or on the cutting machine within 36 inches inby the 
normal working position;
    (2) Conventional section shooting off the solid--on the loading 
machine operator or on the loading machine within 36 inches inby the 
normal working position;
    (3) Continuous mining section other than auger-type--on the 
continuous mining machine operator or on the continuous mining machine 
within 36 inches inby the normal working position;
    (4) Continuous mining machine; auger-type--on the jacksetter who 
works nearest the working face on the return air-side of the continuous 
mining machine or at a location that represents the maximum 
concentration of dust to which the miner is exposed;
    (5) Scoop section using cutting machine--on the cutting machine 
operator or on the cutting machine within 36 inches inby the normal 
working position;
    (6) Scoop section, shooting off the solid--on the coal drill 
operator or on the coal drill within 36 inches inby the normal working 
position;
    (7) Longwall section--on the miner who works nearest the return 
air-side of the longwall working face or along the working face on the 
return side within 48 inches of the corner;
    (8) Hand loading section with a cutting machine--on the cutting 
machine operator or on the cutting machine within 36 inches inby the 
normal working position;
    (9) Hand loading section shooting off the solid--on the hand loader 
exposed to the greatest dust concentration or at a location that 
represents the maximum concentration of dust to which the miner is 
exposed; and
    (10) Anthracite mine sections--on the hand loader exposed to the 
greatest dust concentration or at a location that represents the 
maximum concentration of dust to which the miner is exposed.
    (e) When sampling an occupation other than the DO, the sampling 
device must be placed on the miner assigned to that occupation, unless 
directed otherwise by the district manager.


Sec.  70.207  Approval of dust control parameters by district manager; 
revocation of approval.

    (a) Approval of the dust control parameters specified in the 
ventilation plan will be granted when:
    (1) No valid equivalent concentration measurement exceeds the 
critical values listed in Table 70-1 that correspond to the number of 
shifts sampled, and
    (2) The specified dust control parameters incorporate the 
parameters used during verification sampling.
    (b) MSHA approval may be revoked based on samples collected by MSHA 
or in accordance with Sec.  70.215.

                Table 70-1.--Critical Values for Determining Compliance With Verification Limits
----------------------------------------------------------------------------------------------------------------
                                                                      Critical values
       If samples are submitted for       ----------------------------------------------------------------------
                                                Respirable coal mine dust            Respirable quartz dust
----------------------------------------------------------------------------------------------------------------
1 shift..................................  1.71 mg/m3........................  87 [mu]g/m3
2 shifts.................................  1.85 mg/m3........................  93 [mu]g/m3
3 shifts.................................  1.93 mg/m3........................  97 [mu]g/m3
4 or more shifts.........................  2.0 mg/m3.........................  100 [mu]g/m3
----------------------------------------------------------------------------------------------------------------

Sec.  70.208  Follow-up action when either verification limit is 
exceeded.

    If either verification limit is exceeded, the operator must:
    (a) Stop sampling and make approved respiratory equipment available 
to affected miners in accordance with Sec.  70.300;
    (b) Determine the cause and take action to reduce the concentration 
of respirable dust to within the applicable verification limit; and
    (c) Submit in writing, within 5 calendar days of receiving results 
of sampling, any proposed revision to the plan parameters to the 
district manager. The district manager will notify the operator in 
writing if the proposed revision is provisionally approved and whether 
to resume sampling from the point it was stopped or to begin sampling 
all over again. The district manager may require additional control 
measures before the operator may resume or initiate sampling in 
accordance with the requirements of Sec.  70.206.


Sec.  70.209  Use of supplementary control measures; types and 
conditions for use; request for approval.

    (a) If either verification limit is exceeded and the operator 
believes that the MMU is using all feasible engineering or 
environmental controls, the operator may request the Administrator for 
Coal Mine Safety and Health to approve the use of supplementary control 
measures to reduce exposure of individual miners assigned to work in 
the affected occupations to within the applicable verification limits. 
The operator must provide a copy of the submitted request to the 
representative of miners at the time of submittal. MSHA will consider 
all comments from the representative of miners and provide copies of 
these comments to the operator upon request.
    (b) The Administrator will approve or deny the operator's request 
to use supplementary controls within 30 calendar days or as soon as 
practicable after its receipt by MSHA.
    (1) If approval is denied, the operator will be notified in writing 
of specific reasons for disapproval.
    (2) If approval is granted, the operator will be permitted to use 
either powered air-purifying respirators (PAPRs), approved by NIOSH 
under 42 CFR part 84 and by MSHA under part 18 of this title, 
administrative controls, or a combination of both, provided the 
requirements of Sec. Sec.  70.210 and 70.211 or Sec. Sec.  70.213 and 
70.214 are met. The operator will be permitted to use these

[[Page 10877]]

supplementary controls until additional feasible engineering controls 
become available and are implemented or until the district manager 
revokes the approval.
    (c) MSHA approval to use supplementary controls may be revoked for 
failure to comply with requirements of Sec.  70.211(b) or Sec.  
70.214(b).


Sec.  70.210  Powered air-purifying respirators (PAPRs); requirements 
for approval.

    (a) Within 5 calendar days of receiving MSHA approval to use 
supplementary controls, the operator must submit, in writing, a 
revision to the ventilation plan to the district manager. The proposed 
revision must include:
    (1) Feasible engineering controls capable of:
    (i) Reducing the concentration of respirable dust in every 
occupational environment where a PAPR is required as low as achievable; 
and
    (ii) Maintaining other occupational environments at or below the 
verification limits.
    (2) A written PAPR protection program which meets the requirements 
of Sec.  72.710 and includes:
    (i) The protection factor assigned to the MMU as determined in 
accordance with Sec.  70.2; and
    (ii) The specific occupation(s), work locations or tasks affected 
in the MMU. The district manager may require adjustments in the PAPR 
protection program.
    (3) The location(s) in a MMU where warning signs with the statement 
``RESPIRATORY PROTECTION REQUIRED IN THIS AREA'' will be posted.
    (b) Within 30 calendar days of receiving provisional approval of 
the plan revision, the operator must verify, in accordance with Sec.  
70.206(b) through (e), the adequacy of the proposed revision by 
sampling the occupation(s) being affected by the PAPR protection 
program, the DO, and/or other occupation(s) designated by the district 
manager.


Sec.  70.211  Powered air-purifying respirators (PAPRs); approval and 
conditions for continued use; revocation of approval.

    (a) MSHA approval of the proposed plan revision incorporating a 
PAPR protection program will be granted when:
    (1) No valid equivalent concentration measurement exceeds the 
critical values listed in Table 70-1 to Sec. 70.207 that correspond to 
the number of shifts sampled; and
    (2) The revision incorporates the dust control parameters used 
during verification sampling.
    (b) MSHA may revoke approval to use supplementary controls for 
failure to:
    (1) Comply with the plan requirements on each shift;
    (2) Maintain the equivalent concentration of respirable coal mine 
dust for any occupation affected by a PAPR protection program and other 
occupations within the MMU at or below the applicable dust standard; 
and
    (3) Implement other feasible engineering controls to reduce dust 
concentrations as low as achievable when such controls become 
available. The approved plan parameters will be reviewed every 6 months 
to assure that the operator is using all feasible engineering controls 
and that the plan parameters continue to be effective under current 
operating conditions.


Sec.  70.212  Powered air-purifying respirators (PAPRs); conditions of 
use under special circumstances.

    (a) When unusual operating conditions are either encountered or 
anticipated, which are known to occur briefly and intermittently, and 
the operator has reason to believe that the approved plan parameters 
will not maintain all occupational environments in the MMU in 
compliance with Sec.  70.100 or Sec.  70.101, the operator may submit a 
written request to the district manager, along with a proposed revision 
to the plan parameters, for the use of PAPRs as a supplementary control 
measure to prevent individual miners from being overexposed and to 
comply with the applicable dust standard during such periods. The 
operator must provide a copy of the request to the representative of 
miners at the time of submittal. MSHA will consider all comments from 
the representative of miners and provide copies of these comments to 
the operator upon request.
    (b) The district manager will approve the use of PAPRs on an 
intermittent basis as a result of the operational factors set forth in 
paragraph (a) of this section when the operator:
    (1) Shows that the unusual conditions are atypical, intermittent 
and beyond the control of the operator; and
    (2) Revises the previously approved dust control provisions of the 
ventilation plan to comply with requirements of Sec.  70.210(a)(1), (2) 
and (3) when PAPRs are used.
    (c) The operator also must:
    (1) Notify the district manager and the representative of miners in 
writing or by electronic means within 24 hours of the occurrence of 
unusual conditions which requires the use of PAPRs;
    (2) Comply with the requirements of Sec.  70.211(b)(1) and (2); and
    (3) Not use PAPRs for a period longer than 30 consecutive calender 
days;
    (d) If PAPR use is to exceed 30 consecutive calendar days or if any 
equivalent concentration measurements indicate that miners are being 
overexposed, the operator must revise and verify the adequacy of the 
plan parameters under the prevailing operating conditions.


Sec.  70.213  Administrative controls; requirements for approval.

    (a) Within 5 calendar days of receiving MSHA approval to use 
supplementary controls, the operator must submit, in writing, a 
revision to the ventilation plan to the district manager. The proposed 
revision must include:
    (1) Feasible engineering controls capable of maintaining the 
environment of any occupation under administrative controls and other 
occupational environments at or below the verification limits; and
    (2) The administrative controls to be implemented and the method 
for ensuring that the procedures for such controls are complied with on 
each shift. The district manager may require additional procedures in 
the plan revision.
    (b) Within 30 calendar days of receiving provisional approval of 
the plan revision, the operator must verify, in accordance with Sec.  
70.206(b) through (e), the adequacy of the proposed revision by 
sampling the occupation(s) under administrative control, the DO, and/or 
other occupation(s) designated by the district manager.


Sec.  70.214  Administrative controls; approval and conditions for 
continued use; revocation of approval.

    (a) MSHA will approve the proposed plan revision incorporating the 
use of administrative controls when:
    (1) No valid equivalent concentration measurement exceeds the 
critical values listed in Table 70-1 that correspond to the number of 
shifts sampled; and
    (2) The revision incorporates the dust control parameters used 
during verification sampling.
    (b) MSHA may revoke approval to use supplementary controls for 
failure to:
    (1) Comply with the plan requirements on each shift;
    (2) Maintain the equivalent concentration of respirable coal mine 
dust for any occupation under administrative controls and other 
occupations in the MMU at or below the applicable dust standard; and
    (3) Implement other feasible engineering controls to reduce dust 
concentrations as low as achievable when such controls become 
available. MSHA will review the approved plan

[[Page 10878]]

parameters every 6 months to assure that the operator is using all 
feasible environmental controls and that the plan parameters continue 
to be effective under current operating conditions.


Sec.  70.215  Quarterly evaluation of approved plan parameters.

    (a) For those MMUs designated by MSHA, one valid respirable dust 
sample from the DO and the occupation(s) under supplementary controls 
must be submitted to MSHA on a quarterly basis. The occupations must be 
sampled in accordance with paragraphs (b), (d) and (e) of Sec.  70.206.
    (1) MSHA designates an MMU for sampling when any MSHA equivalent 
concentration measurement exceeds the applicable dust standard by at 
least 0.1 mg/m3.
    (2) Sampling is required until all MSHA and operator sample results 
remain at or below the applicable dust standard for at least four 
quarters.
    (3) Sampling begins during the next quarterly period following MSHA 
designation of the MMU. The quarterly periods are:
    (i) January 1-March 31
    (ii) April 1-June 30
    (iii) July 1-September 30
    (iv) October 1-December 31.
    (b) If any valid equivalent concentration measurement exceeds the 
applicable dust standard by 0.1 mg/m3 or more , the operator 
must, make approved respiratory equipment available to affected miners 
in accordance with Sec.  70.300, unless already under a PAPR protection 
program; and within 15 calender days after receipt of the respirable 
dust sample data report from MSHA:
    (1) Determine the cause and take corrective action to reduce the 
equivalent concentration of respirable coal mine dust to within the 
applicable dust standard;
    (2) Make a record of the reported excessive dust condition. The 
record must include the following:
    (i) Date of sampling;
    (ii) Location within the mine and the occupation where the sample 
was collected;
    (iii) Measured dust concentration of each sample collected;
    (iv) Corrective action being taken to reduce the concentration of 
respirable coal mine dust.
    (c) If any valid equivalent concentration measurement exceeds the 
citation threshold value (CTV) listed in Table 70-2 that corresponds to 
the applicable dust standard, the district manager may require the 
operator to revise the plan parameters and verify their adequacy under 
the prevailing operating conditions.
    (d) MSHA will cite an operator for failure to take corrective 
action to reduce the concentration of respirable dust in accordance 
with Sec.  70.215(c)(1).
    (e) Paragraph (a) of this section does not apply if using a 
personal continuous dust monitor under Sec.  70.220.


Sec.  70.216  Respirable dust samples; transmission by operator.

    (a) Within 24 hours after the end of the sampling shift, the 
operator must transmit, in containers provided by the manufacturer of 
the filter cassette, all samples collected to fulfill the requirements 
of this part, including the control filter cassettes if required to be 
used, to: Respirable Dust Processing Laboratory, Pittsburgh Safety and 
Health Technology Center, Cochrans Mill Road, Building 38, P.O. Box 
18179, Pittsburgh, Pennsylvania 15236-0179, or to any other address 
designated by the district manager.
    (b) The operator must not open or tamper with the seal of any 
filter cassette or alter the weight of any filter cassette before or 
after it is used.
    (c) A person certified to take respirable dust samples must 
properly complete the dust data card for each filter cassette. The card 
must have an identification number identical to that on the cassette 
used to take the sample or used as a control filter and be submitted to 
MSHA with the sample. Each card must be signed by the certified person 
and must include that person's certification number. Samples with data 
cards not properly completed will be voided by MSHA.
    (d) All samples submitted by the operator must be considered taken 
to fulfill the sampling requirement of this part, unless the sample has 
been identified in writing by the operator to the district manager, 
prior to the intended sampling shift, as a sample to be used for 
purposes other than required by this part.
    (e) Paragraphs (a) through (d) of this section do not apply if 
using a PCDM under Sec.  70.220, except when transmitting samples for 
quartz analysis along with the control filter cassette required by 
Sec.  70.220(c).


Sec.  70.217  Respirable dust samples; report to operator; and posting.

    (a) MSHA will provide the operator a report with the following data 
on all samples submitted in accordance with this part and samples 
collected by MSHA:
    (1) The mine identification number;
    (2) The location within the mine from which the samples were taken;
    (3) The result of each sample taken in accordance with this part 
and by MSHA;
    (4) The occupation code, where applicable;
    (5) The reason for voiding any sample; and
    (6) The engineering controls and their measured quantities, 
including other dust control parameters that were being used in the MMU 
when sampled by MSHA.
    (b) The operator must post the following information on the mine 
bulletin board:
    (1) The report of the results of all samples described in paragraph 
(a) of this section and the end-of-shift exposure data if using a 
personal continuous dust monitor (PCDM) under Sec.  70.220.
    (2) The engineering controls and their measured quantities, 
including other dust control parameters that were being used in the MMU 
when sampled by the operator or by MSHA.
    (3) All written notifications from the district manager regarding 
any aspect of the verification procedures, including all correspondence 
submitted by the operator in accordance with Sec. Sec.  70.209 and 
70.212.
    (c) The operator may remove all information pertaining to the 
verification process, such as sample results, the information specified 
in paragraph (b)(3) of this section, and written correspondence, after 
the district manager approves the dust control parameters specified in 
the ventilation plan. The notification required under Sec.  
70.212(c)(1) of the occurrence of special circumstances requiring the 
use of PAPRs must be posted no longer than 30 calendar days or until 
such time when it is no longer necessary to continue to use PAPRs, 
whichever time period is less.
    (d) Results of samples collected by the operator in accordance with 
Sec.  70.215 or by MSHA must be posted for at least 31 calendar days 
following receipt, including the information specified in paragraph 
(b)(2) of this section. If using a PCDM, the end-of-shift exposure data 
and information specified in paragraph (b)(2) of this section must be 
posted for at least 7 calendar days.


Sec.  70.218  Violation of respirable dust standard; issuance of 
citation; action required by operator; and termination of citation.

    (a) If a valid equivalent concentration measurement for any 
occupation sampled by MSHA meets or exceeds the citation threshold 
value (CTV) listed in Table 70-2 that corresponds to the applicable 
dust standard in effect, the operator will be cited for a violation of 
Sec.  70.100 or Sec.  70.101.
    (b) Upon receipt of a citation issued in accordance with paragraph 
(a) of this

[[Page 10879]]

section, the operator must take the following actions within the time 
for abatement fixed in the citation:
    (1) Make respiratory equipment available to affected miners in 
accordance with Sec.  70.300, unless already under a PAPR protection 
program;
    (2) Determine the cause and take corrective action to reduce the 
equivalent concentration of respirable coal mine dust to within the 
applicable dust standard;
    (3) Revise the plan parameters if the corrective action taken 
indicates that the dust control parameters originally approved for the 
MMU are inadequate for the current operating conditions; and
    (4) Notify the district manager, in writing or by electronic means, 
within 24 hours after implementing corrective action(s).
    (c) The citation will be terminated when:
    (1) All valid equivalent concentration measurements of MSHA 
abatement samples are at or below the applicable dust standard. If 
compliance is demonstrated, the plan must incorporate the dust control 
parameters used during MSHA sampling; or,
    (2) The revised plan parameters have been verified for the current 
operating conditions, if required by the district manager.

 Table 70-2.--Citation Threshold Values (CTV) for Citing Respirable Dust
              Violations Based on Single-Shift Measurements
------------------------------------------------------------------------
             Applicable dust standard  (mg/m3)               CTV (mg/m3)
------------------------------------------------------------------------
2.0........................................................         2.33
1.9........................................................         2.22
1.8........................................................         2.11
1.7........................................................          2.0
1.6........................................................         1.90
1.5........................................................         1.79
1.4........................................................         1.68
1.3........................................................         1.58
1.2........................................................         1.47
1.1........................................................         1.36
1.0........................................................         1.26
0.9........................................................         1.15
0.8........................................................         1.05
0.7........................................................         0.94
0.6........................................................         0.84
0.5........................................................         0.74
0.4........................................................         0.64
0.3........................................................         0.53
0.2........................................................         0.43
------------------------------------------------------------------------

Sec.  70.219  Status change reports.

    (a) If there is a change in operational status of the mine or a MMU 
that affects either the sampling requirements of this part or MSHA's 
ability to carry out its sampling responsibilities, the operator must 
report the change to the MSHA District Office or to any other MSHA 
office designated by the district manager. Status changes must be 
reported in writing within 3 working days after the change has 
occurred.
    (b) Each specific operational status is defined as follows:
    (1) Underground mine:
    (i) Producing--has at least one MMU producing material.
    (ii) Nonproducing--no material is being produced.
    (iii) Abandoned--the work of all miners has been terminated and 
production activity has ceased.
    (2) Mechanized mining unit:
    (i) Producing--producing material from a working section.
    (ii) Nonproducing--temporarily ceased production of material.
    (iii) Abandoned--permanently ceased production of material.


Sec.  70.220  Personal continuous dust monitor (PCDM).

    (a) An operator may implement a miner protection program based on 
the use of approved personal continuous dust monitors (PCDM) in 
conjunction with engineering and administrative controls specified in 
the ventilation plan.
    (b) If PCDMs are to be used, the operator may include 
administrative controls in the proposed plan without obtaining approval 
from the Administrator for Coal Mine Safety and Health under Sec.  
70.209. The proposed plan must include:
    (1) The engineering and administrative controls to be used and the 
method for ensuring that such controls are complied with each shift;
    (2) The miners or occupations that will wear a PCDM each shift; and
    (3) The procedures that ensure no miner will be exposed above the 
applicable dust standard in Sec.  70.100(a) or Sec.  70.101.
    (c) The adequacy of the proposed plan in controlling exposure to 
respirable dust must be demonstrated as prescribed in Sec.  70.204 by 
monitoring each miner's exposure. Each PCDM must be operated portal-to-
portal and must remain operational the entire work shift or for 12 
hours, whichever time is less. In addition, the operator must collect a 
respirable dust sample for quartz analysis from each occupation 
specified in paragraph (a) and in accordance with paragraphs (b), (d) 
and (e) of Sec.  70.206. The district manager will approve the proposed 
plan in accordance with Sec.  70.207(a).
    (d) Following approval by the district manager, the exposure of 
each miner on a MMU must be monitored on every shift under the 
prevailing operating conditions, unless the operator demonstrated 
through verification sampling that the exposure of each miner working 
on the same shift is represented by sampling only the DO and/or another 
occupation(s) specified in Sec.  70.206(a). Each PCDM must be operated 
portal-to-portal and must remain operational the entire shift or for 12 
hours, whichever time is less.
    (e) If any end-of-shift equivalent concentration measurement 
exceeds the applicable dust standard by 0.1 mg/m\3\ or more, the 
requirements in paragraphs (c)(1) through (3), (d) and (e) of Sec.  
70.215 will apply.

PART 75--[AMENDED]

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

    Authority: 30 U.S.C. 811.

    6. Section 75.370 of Subpart D is amended by adding paragraph (h) 
to read as follows:


Sec.  75.370  Mine ventilation plan; submission and approval.

* * * * *
    (h) The operator must record the amount of material produced, as 
defined in Sec.  70.2 of this title, by each MMU during each production 
shift, retain the records for six months, and make the records 
available to authorized representatives of the Secretary and the 
miners' representative.
    7. Section 75.371 of Subpart D is amended by revising paragraphs 
(f) and (t) to read as follows:


Sec.  75.371  Mine ventilation plan; contents.

* * * * *
    (f) Section and face ventilation systems used, including drawings 
illustrating how each system is used; and a description of each 
different dust suppression system used on equipment on working 
sections, including any specific work practices used to minimize the 
dust exposure of individual miners, along with information on the 
location of the roof bolter(s) during the mining cycle for each 
continuous miner section, and the cut sequence for each longwall mining 
section. For plans required to be verified pursuant to Sec.  70.204 of 
this title, the length of each normal production shift and the 
verification production level (VPL), as determined in accordance with 
Sec.  70.2 of this title, must be included for each working section.
* * * * *
    (t) The location of each ``designated area,'' and the respirable 
dust controls

[[Page 10880]]

used at the dust generating sources for these locations.
* * * * *
    8. Part 90 is revised to read as follows:

PART 90--MANDATORY HEALTH STANDARDS--COAL MINERS WHO HAVE EVIDENCE 
OF THE DEVELOPMENT OF PNEUMOCONIOSIS

Subpart A--General
Sec.
90.1 Scope.
90.2 Definitions.
90.3 Part 90 option; notice of eligibility; exercise of option.
Subpart B--Dust Standards, Rights of Part 90 Miners
90.100 Respirable dust standard when quartz is not present.
90.101 Respirable dust standard when quartz is present.
90.102 Transfer; notice.
90.103 Compensation.
90.104 Waiver of rights; re-exercise of option.
Subpart C--Sampling Procedures
90.201 Sampling; general requirements.
90.202 Approved sampling devices; maintenance and calibration.
90.203 Approved sampling devices; operation; air flowrate.
90.204 Respirable dust sampling.
90.205 Respirable dust samples; transmission by operator.
90.206 Respirable dust samples; report to operator and Part 90 
miner.
90.207 Violation of respirable dust standard; issuance of citation; 
action required by operator; and termination of citation.
90.208 Status change reports.
Subpart D--Respirable Dust Control Plans
90.300 Respirable dust control plan; filing requirements; contents.
90.301 Respirable dust control plan; approval by district manager; 
copy to Part 90 miner.

    Authority: 30 U.S.C. 811, 813(h).

Subpart A--General


Sec.  90.1  Scope.

    This Part 90 establishes the option of miners who are employed at 
underground coal mines or at surface work areas of underground coal 
mines and who have evidence of the development of pneumoconiosis to 
work in an area of a mine where the average concentration of respirable 
dust in the mine atmosphere during each shift is continuously 
maintained at or below 1.0 milligrams per cubic meter of air. The 
proposed rule sets forth procedures for miners to exercise this option, 
and establishes the right of miners to retain their regular rate of pay 
and receive wage increases. The proposed rule also sets forth the 
operator's obligations, including respirable dust sampling for Part 90 
miners. This Part 90 is promulgated pursuant to section 101 of the Act 
and supercedes section 203(b) of the Act.


Sec.  90.2  Definitions.

    Act. The Federal Mine Safety and Health Act of 1977, Public Law 91-
173, as amended by Public Law 95-164, 30 U.S.C. 801 et seq.
    Active workings. Any place in a coal mine where miners are normally 
required to work or travel.
    Approved sampling device. A sampling device of the constant-flow 
type:
    (1) Approved by the Secretary and the Secretary of Health and Human 
Services under part 74 of this title; or
    (2) Approved by the Secretary when it has been determined that the 
measured concentration of respirable dust can be converted to an 
equivalent concentration as measured with a sampling device approved 
under part 70 of this title.
    Certified person. An individual certified by the Secretary to take 
respirable dust samples and/or to perform the maintenance and 
calibration of approved sampling devices.
    Citation threshold value (CTV). The lowest equivalent concentration 
measurement demonstrating that the applicable dust standard has been 
exceeded at a confidence level of at least 95 percent.
    Concentration. The amount of respirable dust contained per unit 
volume of air.
    District manager. The manager of the Coal Mine Safety and Health 
District in which the mine is located.
    Equivalent concentration. The concentration of respirable coal mine 
dust, as measured by an approved sampling device, converted to an MRE 
8-hour equivalent as follows:
    (1) Multiply the concentration measured by the approved sampling 
device by the constant factor prescribed by the Secretary for that 
device and then apply criteria in paragraph (2) of this definition if 
applicable.
    (2) If the sampled shift is longer than 8 hours, multiply the 
concentration obtained in paragraph (1) of this definition by t/480 
where t is the length of the sampled work shift in minutes.
    Mechanized mining unit (MMU). A set of mining equipment, including 
hand loading equipment, used for the production of material; or a 
specialized set which utilizes mining equipment other than specified in 
Sec.  70.206(d). Each MMU is assigned a four-digit identification 
number by MSHA. The identification number is retained by the MMU 
regardless of where the unit relocates within the mine. When two sets 
of mining equipment are provided in a series of working places and only 
one production crew is employed at any given time on either set of 
mining equipment, the two sets of equipment are identified as a single 
MMU. When two or more MMUs are simultaneously engaged in the production 
of material within the same working section, each such MMU is 
identified separately.
    MRE. The Mining Research Establishment of the National Coal Board, 
London, England.
    MRE instrument. A gravimetric dust sampler with a four channel 
horizontal elutriator developed by the MRE.
    MSHA. The Mine Safety and Health Administration of the Department 
of Labor.
    Normal work duties. Duties which the Part 90 miner performs on a 
routine day-to-day basis in his or her job classification at a mine.
    Part 90 miner. A miner employed at an underground coal mine or at a 
surface work area of an underground coal mine who has exercised the 
option under the old section 203(b) program, or under Sec.  90.3 of 
this part to work in an area of a mine where the average concentration 
of respirable dust in the mine atmosphere during each shift to which 
that miner is exposed is continuously maintained at or below 1.0 
milligrams per cubic meter of air (mg/m3), and who has not 
waived these rights.
    Quartz. Crystalline silicon dioxide (SiO2) as measured 
by:
    (1) MSHA's Analytical Method P-7: Infrared Determination of Quartz 
in Respirable Coal Mine Dust; or
    (2) Any method approved by MSHA as providing a measurement of 
quartz equivalent to that measured by Analytical Method P-7.
    Respirable dust. Dust collected with an approved sampling device.
    Secretary. The Secretary of Labor or a designee.
    Surface work area of an underground coal mine. The surface areas of 
land and all structures, facilities, machinery, tools, equipment, 
shafts, slopes, excavations, and other property, real or personal, 
placed upon or above the surface of such land by any person, used in, 
or to be used in, or resulting from, the work of extracting bituminous 
coal, lignite, or anthracite from its natural deposits underground by 
any means or method, and the work of preparing extracted coal, and 
includes custom coal preparation facilities.

[[Page 10881]]

    Transfer. (1) Any change in the work assignment of a Part 90 miner 
by the operator and includes--
    (i) any change in occupation code of a Part 90 miner;
    (ii) any movement of a Part 90 miner to or from a MMU; or
    (iii) any assignment of a Part 90 miner to the same occupation in a 
different location at a mine.
    (2) A change in work assignment that lasts no longer than one shift 
would not constitute a transfer under Part 90 if circumstances beyond 
the control of the operator interrupt work being performed by a Part 90 
miner because of equipment malfunction or absenteeism, and necessitate 
the operator to temporarily assign the Part 90 miner to perform work 
duties outside of his or her regular work classification.
    Underground coal mine. An area of land and all structures, 
facilities, machinery, tools, equipment, shafts, slopes, tunnels, 
excavations, and other property, real or personal, placed upon, under, 
or above the surface of such land by any person, used in, or to be used 
in, or resulting from the work of extracting in such area bituminous 
coal, lignite, or anthracite from its natural deposits in the earth by 
any means or method, and the work of preparing the coal so extracted.
    Valid sample. A respirable dust sample collected and submitted as 
required by this part, and not voided by MSHA.


Sec.  90.3  Part 90 option; notice of eligibility; exercise of option.

    (a) Any miner employed at an underground coal mine or at a surface 
work area of an underground coal mine who, in the judgment of the 
Secretary of Health and Human Services, has evidence of the development 
of pneumoconiosis based on a chest X-ray, read and classified in the 
manner prescribed by the Secretary of Health and Human Services, or 
based on other medical examinations must be afforded the option to work 
in an area of a mine where the average concentration of respirable dust 
in the mine atmosphere during each shift to which that miner is exposed 
is continuously maintained at or below 1.0 milligrams per cubic meter 
of air (mg/m3). Each of these miners must be notified in 
writing of eligibility to exercise the option.
    (b) Any miner who is a section 203(b) miner on January 31, 1981, 
must be a Part 90 miner on February 1, 1981, entitled to full rights 
under this part to retention of pay rate, future actual wage increases, 
and future work assignment shift and respirable dust protection.
    (c) Any Part 90 miner who is transferred to a position at the same 
or another coal mine must remain a Part 90 miner entitled to full 
rights under this part at the new work assignment.
    (d) The option to work in a low dust area of the mine may be 
exercised for the first time by any miner employed at an underground 
coal mine or at a surface work area of an underground coal mine who was 
eligible for the option under the old section 203(b) program, or is 
eligible for the option under this part by signing and dating the 
Exercise of Option Form and mailing the form to the Chief, Division of 
Health, Coal Mine Safety and Health, MSHA, 1100 Wilson Boulevard, 
Arlington, Virginia 22209.
    (e) The option to work in a low dust area of the mine may be re-
exercised by any miner employed at an underground coal mine or at a 
surface work area of an underground coal mine who exercised the option 
under the old section 203(b) program, or exercised the option under 
this part by sending a written request to the Chief, Division of 
Health, Coal Mine Safety and Health, MSHA, 1100 Wilson Boulevard, 
Arlington, Virginia 22209. The request should include the name and 
address of the mine and operator where the miner is employed.
    (f) No operator shall require from a miner a copy of the medical 
information or notification of any chest X-ray evaluation received from 
the Secretary or Secretary of Health and Human Services.

Subpart B--Dust Standards, Rights of Part 90 Miners


Sec.  90.100  Respirable dust standard when quartz is not present.

    After the 20th calendar day following receipt of notification from 
MSHA that a Part 90 miner is employed at the mine, the operator must 
continuously maintain the average concentration of respirable dust in 
the mine atmosphere during each shift to which the Part 90 miner in the 
active workings of the mine is exposed at or below 1.0 mg/
m3, as measured with an approved sampling device and in 
terms of an equivalent concentration determined in accordance with 
Sec.  90.2.


Sec.  90.101  Respirable dust standard when quartz is present.

    When the respirable dust in the mine atmosphere of the active 
workings to which a Part 90 miner is exposed contains more than 10 
percent quartz, as determined by the average of the most recent three 
MSHA samples, the operator must continuously maintain the average 
concentration of respirable dust in the mine atmosphere during each 
shift to which a Part 90 miner is exposed at or below the applicable 
dust standard, as measured with an approved sampling device and in 
terms of an equivalent concentration determined in accordance with 
Sec.  90.2. The applicable dust standard is determined by dividing the 
average quartz percentage into the number 10. The application of the 
formula must not result in an applicable dust standard in excess of 1.0 
mg/m3.

    Example: Assume a Part 90 miner is on a 1.0-mg/m3 
applicable dust standard (10% quartz or less). If the first MSHA 
sample contains 12.2% of quartz, and the required two subsequent 
samples contained 14.6% and 10.4%, respectively, the average quartz 
percentage would be 12.4% [(12.2% + 14.6% + 10.4%)/3 = 12.4%]. 
Therefore, the average concentration of respirable dust in the mine 
atmosphere associated with that Part 90 miner must, on each shift, 
be maintained at or below 0.8 mg/m3 [10/12.4% = 0.8 mg/
m3].


Sec.  90.102  Transfer; notice.

    (a) Whenever a Part 90 miner is transferred in order to meet the 
applicable dust standard in Sec. Sec.  90.100 or 90.101, the operator 
must transfer the miner to an existing position at the same coal mine 
on the same shift or shift rotation on which the miner was employed 
immediately before the transfer. The operator may transfer a Part 90 
miner to a different coal mine, a newly-created position or a position 
on a different shift or shift rotation if the miner agrees in writing 
to the transfer. The requirements of this paragraph do not apply when a 
Part 90 miner's work position complies with the applicable dust 
standard but circumstances, such as reductions in workforce or changes 
in operational methods, require a change in the miner's job or shift 
assignment.
    (b) On or before the 20th calendar day following receipt of 
notification from MSHA that a Part 90 miner is employed at the mine, 
the operator must give the district manager written notice of the 
occupation and, if applicable, the mechanized mining unit to which the 
Part 90 miner will be assigned on the 21st calendar day following 
receipt of the notification from MSHA.
    (c) After the 20th calendar day following receipt of notification 
from MSHA that a Part 90 miner is employed at the mine, the operator 
must give the district manager written notice before any transfer of a 
Part 90 miner. This notice must include the scheduled date of the 
transfer.


Sec.  90.103  Compensation.

    (a) The operator must compensate each Part 90 miner at not less 
than the regular rate of pay received by that

[[Page 10882]]

miner immediately before exercising the option under Sec.  90.3.
    (b) Whenever a Part 90 miner is transferred, the operator must 
compensate the miner at not less than the regular rate of pay received 
by that miner immediately before the transfer.
    (c) Paragraphs (a) and (b) of this section do not apply when a Part 
90 miner initiates and accepts a change in work assignment for reasons 
of job preference.
    (d) The operator must compensate each miner who is a section 203(b) 
miner on January 31, 1981, at not less than the regular rate of pay 
that the miner is required to receive under section 203(b) of the Act 
immediately before the effective date of this part.
    (e) In addition to the compensation required to be paid under 
paragraphs (a), (b) and (d) of this section, the operator must pay each 
Part 90 miner the actual wage increases that accrue to the 
classification to which the miner is assigned.
    (f) If a miner is temporarily employed in an occupation other than 
his or her regular work classification for two months or more before 
exercising the option under Sec.  90.3, the miner's regular rate of pay 
for purposes of paragraph (a) and (b) of this section is the higher of 
the temporary or regular rates of pay. If the temporary assignment is 
for less than two months, the operator may pay the Part 90 miner at his 
or her regular work classification rate regardless of the temporary 
wage rate.
    (g) If a Part 90 miner is transferred, and the Secretary 
subsequently notifies the miner that notice of the miner's eligibility 
to exercise the Part 90 option was incorrect, the operator must retain 
the affected miner in the current position to which the miner is 
assigned and continue to pay the affected miner the applicable rate of 
pay provided in paragraphs (a), (b), (d) and (e) of this section, 
until:
    (1) The affected miner and operator agree in writing to a position 
with pay at not less than the regular rate of pay for that occupation; 
or
    (2) A position is available at the same coal mine in both the same 
occupation and on the same shift on which the miner was employed 
immediately before exercising the option under Sec.  90.3 or under the 
old section 203(b) program.
    (i) When such a position is available, the operator must offer the 
available position in writing to the affected miner with pay at not 
less than the regular rate of pay for that occupation.
    (ii) If the affected miner accepts the available position in 
writing, the operator must implement the miner's reassignment upon 
notice of the miner's acceptance. If the miner does not accept the 
available position in writing, the miner may be reassigned and 
protections under this Part 90 shall not apply. Failure by the miner to 
act on the written offer of the available position within 15 days after 
notice of the offer is received from the operator shall operate as an 
election not to accept the available position.


Sec.  90.104  Waiver of rights; re-exercise of option.

    (a) A Part 90 miner may waive his or her rights and be removed from 
MSHA's active list of miners who have rights under Part 90 by:
    (1) Giving written notification to the Chief, Division of Health, 
Coal Mine Safety and Health, MSHA, that the miner waives all rights 
under this part;
    (2) Applying for and accepting a position in an area of a mine 
which the miner knows exceeds the applicable dust standard; or
    (3) Refusing to accept another position offered by the operator at 
the same coal mine that meets the requirements of Sec. Sec.  90.100, 
90.101 and 90.102(a) after dust sampling shows that the existing work 
position exceeds the applicable dust standard.
    (b) If rights under this Part 90 are waived, the miner gives up all 
rights under this Part 90 until the miner re-exercises the option in 
accordance with Sec.  90.3(e).
    (c) If rights under this Part 90 are waived, the miner may re-
exercise the option under this part in accordance with Sec.  90.3(e) at 
any time.

Subpart C--Sampling Procedures


Sec.  90.201  Sampling; general requirements.

    (a) Each operator must conduct respirable dust sampling required by 
this part with an approved sampling device to assure that the assigned 
work position of a new or transferred Part 90 miner meets Sec. Sec.  
90.100 or 90.101.
    (b) Sampling must be performed by a certified person. To be 
certified, a person must pass the MSHA examination on sampling of 
respirable coal mine dust.
    (c) The sampling device must be worn by each Part 90 miner, must be 
operated portal-to-portal, and must be operational during the Part 90 
miner's entire work shift.
    (d) Sampling required by this part must be conducted while the Part 
90 miner is performing normal work duties.
    (e) Unless otherwise directed by the district manager, the sampling 
device must be placed:
    (1) On the Part 90 miner;
    (2) On the piece of equipment which the Part 90 miner operates 
within 36 inches of the normal working position; or
    (3) At a location that represents the maximum concentration of 
respirable dust to which the Part 90 miner is exposed.
    (f) Upon request from the district manager, the operator must 
submit the date and time when sampling required by this part will 
begin.


Sec.  90.202  Approved sampling devices; maintenance and calibration.

    (a) Sampling devices must be maintained as approved and calibrated 
by a certified person in accordance with MSHA Informational Report IR 
1240 (1996) ``Calibration and Maintenance Procedures for Coal Mine 
Respirable Dust Samplers ``(supercedes IR 1121).'' To be certified, a 
person must pass the MSHA examination on maintenance and calibration 
for approved sampling devices.
    (b) Sampling devices must be calibrated at the flowrate of 2.0 
liters of air per minute, or at a different flowrate as prescribed by 
the Secretary and the Secretary of Health and Human Services for the 
particular device, before they are put into service and, thereafter, at 
time intervals prescribed by the manufacturer.
    (c) If equipped with a flowmeter, a calibration mark must be placed 
on the flowmeter of each sampling device to indicate the proper 
position of the float when the sampler is operating at a flowrate of 
2.0 liters of air per minute or other flowrate prescribed by the 
Secretary and the Secretary of Health and Human Services for the 
particular device. The standard to denote proper flow is when the 
lowest part of the float is lined up with the top of the calibration 
mark.
    (d) Each sampling device must be tested and examined immediately 
before each sampling shift and necessary external maintenance must be 
performed by a certified person to assure that the sampling device is 
clean and in proper working condition. This testing and examination 
must include the following:
    (1) Testing the voltage of each battery while under actual load to 
assure the battery is fully charged. The voltage for nickel cadmium 
cell batteries must not be lower than the product of the number of 
cells in the battery pack multiplied by 1.25. The voltage for other 
than nickel cadmium cell batteries must not be lower than the product 
of the number of cells in the battery pack multiplied by

[[Page 10883]]

the manufacturer's nominal voltage per cell value;
    (2) Examination of all components of the cyclone to assure that 
they are clean and free of dust and dirt;
    (3) Examination of the inner surface of the cyclone on the approved 
sampling device to assure that it is free of scoring;
    (4) Examination of the external tubing on the approved sampling 
device to assure that it is clean and free of leaks; and
    (5) Examination of the clamping and positioning of the cyclone 
body, vortex finder and cassette to assure that they are rigid, in 
alignment, and firmly in contact.
    (e) In accordance with 5 U.S.C. 552(a) and 1 CFR, part 51, MSHA 
Informational Report No. 1240 (1996) referenced in paragraph (a) of 
this section is hereby incorporated-by-reference. Copies may be 
inspected or obtained at each Coal Mine Safety and Health office of 
MSHA.


Sec.  90.203  Approved sampling devices; operation; air flowrate.

    (a) Sampling devices must be operated at the flowrate of 2.0 liters 
of air per minute, or at a different flowrate as prescribed by the 
Secretary and the Secretary of Health and Human Services for the 
particular device.
    (b) Except as provided in paragraph (c) of this section each 
sampling device must be examined each shift by a person certified to 
sample during:
    (1) The second hour after being put into operation to assure that 
the sampling device is operating properly and at the proper flowrate. 
If the proper flowrate is not maintained, necessary adjustments must be 
made by the certified person.
    (2) The last hour of operation to assure that the sampling device 
is operating properly and at the proper flowrate. If the proper 
flowrate is not maintained, the respirable dust sample must be 
transmitted to MSHA with a notation by the certified person on the back 
of the dust data card stating that the proper flowrate was not 
maintained. Other events occurring during sampling that may affect the 
validity of the sample must also be noted on the back of the dust data 
card.
    (c) Paragraph (b)(1) of this section will not apply if the sampling 
device is being operated in a breast or chamber of an anthracite coal 
mine where the full box mining method is used.


Sec.  90.204  Respirable dust sampling.

    (a) The operator must collect five valid samples for each Part 90 
miner within 15 calendar days after:
    (1) The 20-day period specified for each Part 90 miner in Sec.  
90.100; and
    (2) Implementing any transfer after the 20th calendar day following 
receipt of notification from MSHA that a part 90 miner is employed at 
the mine; and
    (b) When any valid sample collected in accordance with either 
paragraph (a) or (b) of this section exceeds the applicable dust 
standard by at least 0.1 mg/m3, the operator must, within 15 
calendar days following receipt of notification from MSHA:
    (1) Take corrective action by reducing the respirable dust level in 
the Part 90 miner's assigned work position or transferring the Part 90 
miner to another work position that meets the applicable dust standard; 
and
    (2) Sample the affected Part 90 miner until five valid samples are 
collected.
    (c) When any valid sample taken in accordance with paragraph (b)(2) 
of this section exceeds the applicable dust standard by at least 0.1 
mg/m3, the operator will be cited for a violation of 
paragraph (b)(1) of this section.


Sec.  90.205  Respirable dust samples; transmission by operator.

    (a) Within 24 hours after the end of the sampling shift, the 
operator must transmit, in containers provided by the manufacturer of 
the filter cassette, all samples collected to fulfill the requirements 
of this part to: Respirable Dust Processing Laboratory, Pittsburgh 
Safety and Health Technology Center, Cochrans Mill Road, Building 38, 
P.O. Box 18179, Pittsburgh, Pennsylvania 15236-0179, or to any other 
address designated by the district manager.
    (b) The operator must not open or tamper with the seal of any 
filter cassette or alter the weight of any filter cassette before or 
after it is used.
    (c) A person certified to take respirable dust samples must 
properly complete the dust data card for each filter cassette. The card 
must have an identification number identical to that on the cassette 
used to take the sample and be submitted to MSHA with the sample. Each 
card must be signed by the certified person and must include that 
person's certification number. Samples with data cards not properly 
completed will be voided by MSHA.
    (d) All samples submitted by the operator must be considered taken 
to fulfill the sampling requirements of this part, unless the sample 
has been identified in writing by the operator to the district manager, 
prior to the intended sampling shift, as a sample to be used for 
purposes other than required by this part.


Sec.  90.206  Respirable dust samples; report to operator and Part 90 
miner.

    (a) MSHA will provide the operator a report with the following data 
on all samples submitted by the operator in accordance with this part 
and samples collected by MSHA:
    (1) The mine identification number;
    (2) The location within the mine from which the samples were taken;
    (3) The results of each sample taken in accordance with this part 
and by MSHA;
    (4) The occupation code;
    (5) The reason for voiding any sample;
    (6) The Social Security Number of the Part 90 miner; and
    (7) The respirable dust control measures that were being used in 
the position of the Part 90 miner sampled by MSHA and their measured 
quantities;
    (b) Upon receipt, the operator must provide a copy of this report 
to the Part 90 miner. The operator must not post the original or a copy 
of this report on the mine bulletin board.


Sec.  90.207  Violation of respirable dust standard; issuance of 
citation; action required by operator; and termination of citation.

    (a) If a valid equivalent concentration measurement for any Part 90 
miner sampled by MSHA meets or exceeds the citation threshold value 
(CTV) listed in Table 70-2 to Sec. 70.218 of this title that 
corresponds to the applicable dust standard in effect, the operator 
will be cited for a violation of Sec.  90.100 or Sec.  90.101.
    (b) Upon receipt of a citation issued in accordance with paragraph 
(a) of this section, the operator must take the following action within 
the time for abatement fixed in the citation:
    (1) Make approved respiratory protection equipment available to the 
affected Part 90 miner in accordance with Sec.  70.300;
    (2) Determine the cause and take corrective action to reduce the 
equivalent concentration of respirable coal mine dust to within the 
applicable dust standard. If the corrective action involves:
    (i) Reducing the respirable dust level in the position of the Part 
90 miner, the operator must notify the district manager, in writing or 
by electronic means, within 24 hours after implementing the control 
measures.
    (ii) Transferring the Part 90 miner to another position at the mine 
to meet the applicable dust standard, the operator must comply with 
Sec.  90.102(c) and then sample the affected miner until five valid 
samples are collected.
    (c) The citation will be terminated when a valid equivalent 
concentration measurement taken by MSHA is at or below the applicable 
dust standard. If the violation was abated by:

[[Page 10884]]

    (1) Reducing the respirable dust level in the working position of 
the Part 90 miner, the operator must submit a respirable dust control 
plan to the district manager for approval in accordance with Sec.  
90.300.
    (2) Transferring the Part 90 miner to another position at the mine, 
a respirable dust control plan is not required to be submitted to the 
district manager for approval.


Sec.  90.208  Status change reports.

    If there is a change in the status of the Part 90 miner that either 
affects the sampling requirements of this part or MSHA's ability to 
carry out its sampling responsibilities (such as entering a terminated, 
injured or ill status, or returning to work), the operator must report 
the change in the status of the Part 90 miner to the MSHA District 
Office or to any other MSHA office designated by the district manager. 
Status changes must be reported in writing within 3 working days after 
the status change has occurred.

Subpart D--Respirable Dust Control Plans


Sec.  90.300  Respirable dust control plan; filing requirements; 
contents.

    (a) Within 15 calendar days after the termination date of a 
citation for violation of Sec.  90.100 or Sec.  90.101, the operator 
must submit to the district manager for approval a written respirable 
dust control plan applicable to the Part 90 miner in the position 
identified in the citation. The dust control plan and revisions thereof 
must be suitable to the conditions and the mining system of the coal 
mine and must be adequate to continuously maintain respirable dust 
within the permissible concentration for the Part 90 miner in the 
position identified in the citation.
    (b) The dust control plan must contain the information described 
below and any additional provisions required by the district manager:
    (1) The mine identification number assigned by MSHA, the operator's 
name, mine name, mine address, and mine telephone number and the name, 
address and telephone number of the principal officer in charge of 
health and safety at the mine;
    (2) The name and Social Security number of the Part 90 miner and 
the position at the mine to which the plan applies;
    (3) A detailed description of the specific dust control measures 
used to abate the violation of Sec.  90.100 or Sec.  90.101; and
    (4) A detailed description of how each of the dust control measures 
described in response to paragraph (b)(3) of this section will continue 
to be used by the operator, including at least the specific time, place 
and manner the control measures will be used.


Sec.  90.301  Respirable dust control plan; approval by district 
manager; copy to Part 90 miner.

    (a) The district manager will approve each dust control plan on a 
mine-by-mine basis. Additional measures may be required in plans by the 
district manager. When approving such plans, the district manager will 
consider the results of MSHA sampling and whether:
    (1) The dust control measures specified in the plan would be likely 
to continuously maintain compliance with the applicable dust standard; 
and
    (2) The operator's compliance with all plan provisions could be 
readily verified by MSHA.
    (b) MSHA will conduct sampling to monitor the continued 
effectiveness of the approved plan provisions in maintaining compliance 
with the applicable dust standard.
    (c) The operator must comply with all plan provisions upon notice 
from MSHA that the dust control plan is approved.
    (d) The operator must provide a copy of the dust control plan 
required under this part to the Part 90 miner. The operator must not 
post the original or a copy of the plan on the mine bulletin board.
    (e) The operator may review respirable dust control plans and 
submit proposed revisions to such plans to the district manager for 
approval.

[FR Doc. 03-3941 Filed 3-5-03; 8:45 am]
BILLING CODE 4510-43-P