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

Federal RegisterJul 7, 2000

Ask Donna

What actually matters in this document.

Text

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 hearings.

SUMMARY:

MSHA is proposing to revoke existing operator respirable dust sampling procedures under parts 70 and 90, and to implement new regulations that would require each underground coal mine operator to have a verified mine ventilation plan. Under this proposal, MSHA would verify the effectiveness of the mine ventilation plan for each mechanized mining unit (MMU) in controlling respirable dust under typical mining conditions. MSHA would collect full-shift respirable dust samples, called “verification 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 2.0 mg/m

and 100

g/m

, respectively. The adequacy of these parameters would be demonstrated on shifts during which the amount of the 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.

The proposal would require mine operators to: First, set and maintain the dust control parameters during MSHA verification sampling at levels specified in the plan; second, maintain and make available to MSHA records of the amount of material produced by each mechanized mining unit during each production shift; and third, additional information in mine ventilation plans. For longwall mine operations, MSHA is also proposing to permit the use of either approved powered, air-purifying respirators (PAPRs) or verifiable administrative controls as a supplemental means of compliance if MSHA has determined that further reduction in respirable dust levels cannot be achieved using all feasible engineering or environmental controls appropriate for the operational conditions involved. In addition, through this rule, MSHA would conduct all compliance and abatement sampling under existing parts 70 and 90.

DATES:

Comments on the proposed rule should be submitted on or before August 7, 2000.

We are also announcing that we will hold public hearings on the proposed rule within 30 to 45 days of the publication of this rule. The hearing dates, times and specific locations will be announced by a separate document in the

Federal Register

. The rulemaking record will remain open 7 days after the last public hearing.

ADDRESSES:

You may use mail, facsimile (fax), or electronic mail to send your comments to MSHA. Clearly identify comments as such and send them—(1) By mail to: Carol J. Jones, Director, Office of Standards, Regulations, and Variances, MSHA, 4015 Wilson Boulevard, Room 631, Arlington, VA 22203;

(2) By fax to: MSHA, Office of Standards, Regulations, and Variances, 703-235-5551; or

(3) By electronic mail to: comments@msha.gov. Written comments on the information collection requirements may be submitted directly to the Office of Information and Regulatory Affairs, OMB, New Executive Office Building, 725 17th Street, NW, Washington, DC 20503, Attn: Desk Officer for MSHA; and to Carol J. Jones, Director, Office of Standards, Regulations, and Variances, MSHA 4015 Wilson Boulevard, Room 631, Arlington, VA 22203; by facsimile to MSHA, at 703-235-5551; or by electronic mail to comments@msha.gov.

The hearings will be held in the following locations: Prestonsburg, Kentucky, (Jenny Wiley State Resort Park); Morgantown, West Virginia; and Salt Lake City, Utah. The hearing dates, times and specific locations will be announced by a separate document in the

Federal Register

FOR FURTHER INFORMATION CONTACT:

Carol J. Jones, Director, Office of Standards, Regulations, and Variances, MSHA; 703-235-1910.

SUPPLEMENTARY INFORMATION:

I. Table of Contents

The preamble discusses: revocation of existing operator respirable dust sampling requirements, revised procedures for adjusting the respirable dust standard when quartz is present, the proposed rule, engineering controls for respirable coal mine dust, dust control parameters, supplemental controls, health effects of exposure to respirable coal mine dust, degree and significance of the reduction in the number of shifts during which there are overexposures, an analysis of the technological and economical feasibility of this proposed rule, and regulatory impact and flexibility analyses.

The preamble discussion follows this outline:

I. Table of Contents

II. Background

A. Coal Mine Respirable Dust Task Group

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

III. General Discussion

A. Revocation of the Operator Dust Sampling Program

1. Pre-1980 Sampling Program

2. Post-1980 Sampling Program

3. Issues Affecting the Credibility of Operator Compliance Sampling

4. Proposed Reforms to the Respirable Dust Monitoring Program

a. Bimonthly Sampling

b. Abatement Sampling

c. Advantages of MSHA Compliance Sampling Over Existing Program

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

1. Current Procedures

2. Proposed Revised Procedures

3. Validity of Averaging Percentages

C. Respirable Dust Control Program for Underground Coal Mines

1. Evaluating and Approving Plan Requirements for Respirable Dust Control

2. Compliance with Plan Requirements for Respirable Dust Control

3. Monitoring Effectiveness of Plan Requirements for Respirable Dust Control

(a) Monitoring by Mine Operators

(b) Monitoring by MSHA

4. Proposed Procedures for Evaluating, Approving, and Monitoring Plan Requirements

D. Hierarchy of Dust Controls

1. Selection of Respirators: Loose-Fitting PAPRs

2. Protection Factor for Loose-fitting Powered, Air-Purifying Respirators

E. Guidelines for Determining What is a Feasible Dust Control

F. Application of Continuous Monitoring Technology to Prevent Overexposure on Individual Shifts

IV. Discussion of Proposed Rule

A. Summary

B. Section-by-Section Discussion

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 (CWP) and Progressive Massive Fibrosis (PMF)

b. Other Health Effects

2. Toxicological Literature

3. Epidemiological Literature

a. Simple Coal Workers' Pneumoconiosis (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. Regulatory Impact Analysis

A. Costs and Benefits: Executive Order 12866

1. Compliance Costs

2. Benefits

B. Regulatory Flexibility Certification and Initial Regulatory Flexibility Analysis

X. Other Statutory Requirements

A. Plain Language

B. Unfunded Mandates Reform Act of 1995

C. Paperwork Reduction Act of 1995

D. National Environmental Protection Act

E. Executive Order 12630 (Governmental Actions and Interference with Constitutionally Protected Property Rights)

F. Executive Order 12988 (Civil Justice)

G. Executive Order 13045 (Protection of Children from Environmental Health Risks and Safety Risks)

H. Executive Order 13084 (Consultation and Coordination with Indian Tribal Governments)

I. Executive Order 13132 (Federalism)

XI. Public Hearings

Appendix A. Derivation of the Critical Values

Appendix B. References

XII. Regulatory Text

II. Background

Maintaining a work environment free of excessive levels of respirable coal mine dust and quartz dust (respirable dust) is essential for long-term health protection. Through the joint promulgation of the single, full-shift sample and plan verification proposals, miners would be further protected from the debilitating effects of occupational

respiratory disease by limiting their exposures to respirable coal mine dust to no more than the applicable standard on each shift.

For details, see Quantitative Risk Assessment and Significance of Risk Sections.

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/m

). Under current MSHA regulations, when coal mine dust contains more than five percent quartz, the respirable coal mine dust standard is further reduced, by means of a formula. Although MSHA does not currently 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 quartz concentrations to 100

g/m

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 work environment where miners work or travel through the application of feasible environmental or engineering control measures. Engineering or environmental control of respirable dust in the mine environment is the ultimate dust-control technique and the principal method for protecting miners' health. These include all methods that control respirable dust levels 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. For full compliance, mine operators must develop, implement, and maintain effective engineering or environmental control measures, and evaluate them at regular intervals to assure that they function as intended. These control measures or “dust control parameters,” are specified in the dust control portion of the operator's mine ventilation plan currently required under § 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 is 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. Section 70.2 defines an MMU to mean “a unit of mining equipment including hand loading equipment used for the production of material.” The plans provide a description of specific engineering control measures in use. The plans also contain 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. By monitoring the parameters, one can be assured that respirable dust levels are being adequately controlled without needing to rely on repeated dust sample analyses.

Implementing dust control parameters, which 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 currently used in underground coal mines, adhering to effective ventilation plans is the only practical means of reasonably assuring, 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. Based on the recommendations of the MSHA 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 § 75.362 are important for an effective respirable dust control strategy.

Recent advances in technology may 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). Section 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 for real-time data on the performance, the condition of key dust control parameters, and for immediate modification of controls, 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 inspector sampling results, the average dust concentration in the environment of a continuous miner operator (occupation code—036) has been reduced by 86 percent over the past 30 years, from 7.7 mg/m

to approximately 1.1 mg/m

. This accounts for the significant decline in the percentage of operator continuous miner designated occupation (DO) samples exceeding 2.0 mg/m

, from 49 percent (over 32,000 samples/shifts) in 1971, to 10 percent (over 2,500 samples/shifts) in 1999. Analysis of all valid operator DO samples indicates that in 1971, the 2.0 mg/m

-dust standard was exceeded on 53,463 (44 percent) of the 122,404 shifts sampled, compared to 3,002 (10 percent) of the 28,727 shifts sampled in 1999 (MSHA, DO Samples by Calendar Year, 1999). 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).

Certain aspects of the current respirable dust program limit MSHA's ability to assure the adequacy of the dust control parameters under typical mining conditions according to two expert panels which reviewed the federal program designed to prevent pneumoconiosis among coal miners. Both the

Coal Mine Respirable Dust 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,

established in 1995 by the Secretary of Labor, considered all aspects of the respirable coal mine dust control program and made recommendations for improvement.

A. Coal Mine Respirable Dust Task Group

In response to concerns about the Federal coal mine dust program (MSHA, 1992), MSHA's

Coal Mine Respirable Dust Task Group

(the 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. Among other recommendations, the Task Group recommended that MSHA require mine ventilation plans to be effective under typical mining conditions.

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 inspectors 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 quantity 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 volume quantities, air velocities, water spray pressures, etc., specified in the plan are considered to be a minimum 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 inspectors 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.

The Task Group determined that the use of minimum production levels for evaluating the effectiveness of dust control parameters can result in marginal or inadequate plans. A more detailed discussion of the impact of production on the quality of dust control parameters specified in mine ventilation plans is provided later in this document (in sections III.C.1. and IV.B.). 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 a “normal production shifts” for sampling purposes.

A follow-up survey conducted by MSHA in 1994 found that 43 percent or 539 of the 1,245 producing MMUs, worked at least a 9-hour shift. The Task Group also 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 recommendations of Advisory Committee on the Elimination of Pneumoconiosis Among Coal Mine Workers, which was convened in 1995.

B. 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

(the Advisory Committee). The 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 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 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 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 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 proposal:

1. MSHA should take full responsibility for all compliance sampling at a level which assures representative samples of respirable dust exposures under usual conditions of work without adversely impacting the remainder of the Agency's resources and responsibilities.

2. MSHA should, in consultation with the operator, perform scheduled independent dust monitoring to verify the operator's plan.

3. MSHA should redefine the range of production levels which must be maintained during sampling to verify the plan. The value should be sufficiently close to maximum anticipated production level in order to reasonably assure that the plan would be effective under typical operations.

4. MSHA should review compliance and production records to determine when there is a need for plan verification and modification.

5. MSHA should require that the results and monitoring of dust control parameters and production be recorded in order to correlate dust control parameters with dust measurements.

This proposal 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 Advisory Committee in the current respirable coal mine dust program. The proposal would revoke 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 the applicable standard on each shift. These ventilation plans would be verified by MSHA using single, full-shift respirable dust samples. The plans' effectiveness would be monitored on a regular basis by the use of inspector single, full-shift samples. The proposed rule regarding the use of single, full-shift measurements of respirable coal mine dust to determine average concentration is also published in today's

Federal Register

MSHA recognizes that the Secretary of Labor's Advisory Committee on the Elimination of Pneumoconiosis Among Coal Workers made several recommendations that also impact on surface coal mine workers. These surface coal mine issues will be addressed by the agency in a separate rulemaking which is currently underway. The scope of that rulemaking will include many of the issues that are addressed in this underground rule including requirements for duct control plans, verification of dust control plans prior to approval, on shift examination of dust control measures, and the elimination of operator sampling for compliance purposes.

III. General Discussion

This section describes the current respirable coal mine dust program and the role of mine ventilation plans in safeguarding the health of miners. Specifically, this section details:

(1) The reasoning behind MSHA's decision to revoke the operator dust sampling programs under 30 CFR parts 70 and 90 and to take full responsibility for all compliance sampling;

(2) The proposed procedures for arriving at an average quartz percentage that is used to establish an applicable dust standard under §§ 70.101 and 90.101;

(3) The existing means for evaluating the effectiveness of dust control parameters stipulated in mine ventilation plans;

(4) The plan approval process;

(5) Methods of assuring compliance with plan requirements; and

(6) MSHA's efforts to monitor plan effectiveness on a regular basis.

There is also a detailed discussion of the hierarchy of dust controls and the continued need for mine ventilation plans to specify dust control parameters in order to preserve the primacy of engineering controls. Finally, as a possible alternative to plan verification, we have included a discussion and a request for comments on the application of personal continuous monitoring technology which is, or may become available, to prevent overexposure on individual shifts.

A. Revocation of the Operator Dust Sampling Program

Under the Federal Coal Mine Health and Safety Act of 1969 (Coal Act) coal mine operators were required to take accurate dust samples at periodic intervals to measure the amount of respirable dust in the mine atmosphere where miners work or travel. The Coal Act also required that citations be issued whenever respirable dust samples collected either by an operator or by federal mine inspectors showed noncompliance with the applicable dust standard. The Coal Act was amended in 1977 (Mine Act), but the respirable dust provisions remained essentially unchanged.

1. Pre-1980 Sampling Program

In 1970, federal regulations were issued that established the first comprehensive coal mine operator dust sampling program. Those regulations required the environment of the occupation on a working section, or MMU, exposed to the highest respirable dust concentration to be sampled—the “high risk” occupation concept. All other miners working in the MMU in less risky occupations were assumed to be protected from excessive concentrations of respirable coal mine dust if the high risk occupation was in compliance. Under the program, each operator was required to initially collect and submit ten valid respirable dust samples to determine the average dust concentration (across ten production shifts). If analysis showed the average dust concentration to be within the applicable dust standard, the operator was required to submit only five valid samples a month. If compliance continued to be demonstrated, the operator was required to submit only five valid samples every other month. The initial, monthly, and bimonthly sampling cycles were referred to as the “original,” “standard,” and “alternative” sampling cycles, respectively. When the average dust concentrations exceeded the standard, the operator reverted back to the standard sampling cycle.

Additionally, each working miner was sampled individually every 120 or 180 days, depending on the miner's work assignment, or every 90 days for each miner (now referred to as a part 90 miner) who had a positive chest x-ray for coal workers' pneumoconiosis (CWP) and who elected to exercise the option of transferring to a less dusty area. However, except for the part 90 miner results, these early individual sample results were not used for enforcement, but were forwarded to the National Institute for Occupational Safety and Health (NIOSH) to develop a comprehensive exposure data base for research concerning black lung disease. Each sample was accompanied by a completed mine data card that included, among other things, the occupation and social security number of the sampled miner. This information was also included in the Agency's computer print-out of sampling results that was sent to mine operators.

2. Post-1980 Sampling Program

In 1980, following hearings held throughout the coal fields (in 1977 and 1978), regulations governing operator sampling were substantially revised by reducing the operator sampling burden, to simplify the sampling process, and to enhance the overall quality of the sampling program. The result was to replace the various sampling cycles with a bimonthly sampling cycle and to eliminate the requirement that each working miner be sampled. These are the regulations that currently govern the mine operator dust sampling program. Like the 1970 rules, the current regulations continue to rely on sampling the environment of the DO in the MMU that is exposed to the greatest concentration of respirable coal mine dust, but reduced the number of shifts required to be sampled from ten to five.

Other changes included replacing the requirement that each working miner be sampled individually with the bimonthly collection of one sample from each “designated area” (DA) to measure the dust concentrations associated with dust-generating sources in the active workings of the mine, such as along haulage ways, at underground crushers, or at transfer points. These locations are strategically selected so that the environment where miners normally work or travel is monitored for compliance with the applicable dust

standard. The operator's approved ventilation plan identifies the specific locations where DA samples are required to be collected and the dust control measures used at these locations. Another change was to increase the frequency of sampling part 90 miners from every 90 days to one sample every 60 days.

The revised regulations also eliminated the reporting of personal identifiers on the dust data card due to miner concerns that the data may be used by mine operators to characterize the exposure of an individual miner in future black lung claims. It also provided for sampling equipment to be properly maintained and calibrated, and examined during the shift. Additionally, operators' were required to demonstrate a certain level of competence by passing a test administered by MSHA. Since proper use of sampling equipment is essential to the integrity of the sampling process, the certification requirement was intended to provide reasonable assurance that the person conducting sampling was competent to perform the task. After samples have been collected, certified persons are required to properly fill out the dust data card that accompanies each filter cassette. These samples must then be transmitted unaltered to MSHA within 24 hours after the end of each sampling shift, to expedite compliance determinations and minimize periods of miner overexposure.

While not specified in the regulations, operators are permitted by practice to note on the dust data card any reason why they believe the sample(s) transmitted are not valid and should not be used by MSHA to determine compliance. Generally, such samples are voided by MSHA and the operator is required to submit a substitute sample within that bimonthly sampling period.

MSHA may also determine that an operator sample is invalid for many of the same reasons. MSHA may also void operator samples for technical and administrative reasons, such as samples submitted in excess of the number required, or DO samples if they were not taken during a “normal production shift.” “Normal production shift” is defined in existing §§ 70.2(k)(1), 70.207(a) and (d) as a “production shift during which the amount of material produced * * * is at least 50 percent of the average production for the last set of five valid samples * * *”

After MSHA has processed the samples, the operator is provided with a report of the sample results, which must be posted on the mine bulletin board for a period of 31 days to provide miners ready access to current information on respirable dust conditions in the mine. Operators are also required to report to MSHA in writing any change in the operating status of the mine, mining unit, or designated area that affects the sampling requirements, within three working days after the change occurs.

An operator who is found to be in violation of the reduced dust standard is issued a citation and must take steps to reduce the dust levels. After corrections have been made, the operator must collect five additional samples within a time period specified by MSHA to demonstrate compliance.

During the development of the 1980 regulations for operator sampling requirements, we received comments that indicated a lack of confidence in our reliance on operator samples for enforcement purposes. In response to these concerns, MSHA published a proposed regulation in 1980 that would have provided miners' representatives the right to observe each phase of the operator dust sampling process with no loss in pay. The proposal intended to promote better cooperation between mine operators and miners in order to improve the effectiveness of the program. In 1985, the Agency decided not to finalize regulations to provide miners' representatives the right to observe operator sampling, stating that compliance with the 1980 revisions to the sampling program had resulted in greater confidence in the overall dust program.

3. Issues Affecting the Credibility of Operator Compliance Sampling

As noted earlier in this proposal, there is general agreement that significant efforts have been made during the past 30 years to reduce dust levels in our Nation's mines. While most mine operators have conscientiously attempted to sample miners' exposure to respirable coal mine dust as required by regulation, because of the actions of some, the operator sampling program continues to be plagued by allegations of fraudulent sampling practices. Despite MSHA's efforts to improve the quality of the operator dust sampling program and to vigorously investigate such allegations and prosecute violators, sampling irregularities continue to be documented involving the physical alteration of the weight of dust collected on the filter, or the collection of samples in low-dust areas of the mine or even outside of the mine.

The Advisory Committee found that during the 10 years prior to the publication of their report, serious questions had been raised regarding the representativeness of respirable dust levels measured by mine operators, the handling of filter cassettes, and the changing of work assignments and/or working conditions during sample collection. The credibility of the operator sampling program was questioned by almost all the representatives of miners who testified before the Advisory Committee. Since 1990, more than 160 mine operators, agents and contractors have pled or been found guilty of submitting fraudulent samples to MSHA. These disclosures correspond with the concerns expressed by critics of the operator sampling program.

Detailed reviews of the respirable dust program by the Task Group and the Advisory Committee identified aspects of the current program that have the potential to negatively affect validity of sampling results which could impact miner health protection and, consequently, its credibility in the minds of the very people the program was designed to protect, the miner. For example, to effectively monitor the mine environment where miners work or travel, it is essential that respirable dust samples are “representative,” in that they reflect typical dust conditions to which miners are exposed. The recurrent pattern of disclosures of tampering with the sampling process has highlighted the vulnerability of the current monitoring system to the submission of unrepresentative samples. For example, during the period 1980 to 1990, over 137,000 of the 750,000, or approximately 18 percent of the operator DO samples showed extremely low concentrations (less than or equal to 0.1 mg/m

), compared to 10 percent for the MSHA samples. Since 1990, 14 percent of the operator DO samples and 3 percent of the MSHA samples were equal to 0.1 mg/m

The fact that sampling is controlled by the mine operator also allows the operator to determine when and under what conditions samples will be collected during all current bimonthly and abatement sampling. This permits the operator to conduct sampling during those periods in the mining cycle when conditions are anticipated to result in lower dust levels in the mine environment. For example, the operator may choose to sample during periods when the volume of air on the MMU is greatest or when ventilation controls are operating at optimum efficiently. Accordingly, these sample results may not be representative of typical exposure levels. Other aspects of the monitoring system that may allow the submission of unrepresentative samples were reported by the Task Group in its report of

findings. Because some operators do not sample every bimonthly period or fail to submit the required number of bimonthly samples, miners may be potentially exposed to excessive levels of respirable dust.

4. Proposed Reforms to the Respirable Dust Monitoring Program

Believing 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, one of the 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. It also recommended that compliance sampling should be carried out at a number and frequency at least at the level required of operators and MSHA.

Accordingly, MSHA is proposing to revoke the operator dust sampling programs under 30 CFR parts 70 and 90 and to take full responsibility for all compliance sampling (i.e., bimonthly 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, as modified herein.

(a) Bimonthly Sampling

MSHA would collect a full-shift sample from the working environment of at least five different occupations, if available, on each producing MMU, instead of sampling only the DO for five consecutive shifts or on shifts worked on five consecutive days as under the current bimonthly sampling program. Proposed revised § 70.2(j) defines full shift, for purposes of bimonthly compliance sampling, as the entire work shift including travel time but excluding any time in excess of 480 minutes. A full-shift sample would also be collected from each DA located inby the section dumping point (

i.e.

, intake air and roof bolter DAs) bimonthly, and from all other DAs once each year. All part 90 miners would be sampled bimonthly as under the current program.

MSHA would issue a citation for noncompliance when a single, full-shift measurement demonstrates, at a high level of confidence, that the applicable dust standard is exceeded. Although MSHA would collect multiple occupational samples from each MMU, we would issue only one citation on a single shift on any one MMU unless more than one dust-generating source was involved.

(b) Abatement Sampling

Under this proposal, MSHA would also assume responsibility for all abatement sampling. As recommended by the Advisory Committee, MSHA would utilize single, full-shift 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 bimonthly sampling, MSHA does not anticipate issuing many citations to MMUs and sectional DAs. However, should an MMU be cited for violation of the applicable dust standard, and a determination be made by the inspector who was onsite that the dust control parameters are no longer adequate for the present operating conditions, MSHA would require the operator to revise the dust control portion of the mine ventilation plan under proposed § 70.219. MSHA would then verify the effectiveness of the revised plan. Citations for violating the applicable dust standard would not be based on verification sampling.

If on the other hand, a determination is made that a change in the plan is not warranted, the operator would take corrective action to prevent miners from being exposed on subsequent shifts. MSHA would then sample the MMU, similarly to bimonthly compliance purposes described previously in paragraph (a) of this section. All five of the occupational samples taken on a single shift would have to be below the applicable standard to demonstrate abatement. If any sample result exceeds the applicable standard, but not at a sufficiently high level of confidence to warrant a citation, then MSHA may sample additional shifts or initiate the plan verification process.

We solicit comments on whether MSHA should require a higher level of confidence that the applicable standards are being complied with before abating a citation for excessive dust. Specifically, should abatement determinations be based on the critical values specified in § 70.209? We also solicit comments on whether abatement sampling should be conducted at or above the Verification Production Level (VPL) as defined in § 70.2(aa). Requiring that abatement be demonstrated under more typical production conditions, as represented by the VPL, would provide assurance that miners will continue to be protected on a majority of the production shifts.

MSHA proposes to conduct abatement sampling involving non-MMU DAs and part 90 miners in the same way as it conducts bimonthly sampling. A violation would be abated if the result of an abatement sample was less than the applicable standard. If sample results exceed the applicable standard but not at a sufficiently high level of confidence to warrant a citation, MSHA may collect additional single, full-shift samples.

As in the case of MMU abatement samples, we solicit comments on whether MSHA should require a higher level of confidence that abatement samples for non-MMU DAs and for part 90 miners demonstrate compliance with the applicable standards before abating a citation for excessive dust. Specifically, should abatement determinations be based on the critical values specified in § 70.209?

According to section 101(a)(9) of the Mine Act, no health standard promulgated under this title shall reduce the protection afforded miners by an existing mandatory health standard.

For the reasons listed below, MSHA believes that, through the joint promulgation of this proposed rule and the proposed single, full-shift sample rule, miners would be further protected from the debilitating effects of occupational respiratory disease by limiting their exposures to respirable coal mine dust and quartz dust on every shift.

• 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, for the first time, have been determined effective under typical mining conditions, will provide reasonable assurance that no miner will be overexposed on individual shifts.

• Implementing single, full-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 MSHA would be sampling fewer shifts, MSHA believes the proposed sampling methodology

would provide a more accurate representation of dust conditions to which miners are exposed.

• Under the existing operator sampling program, only the DO is sampled. Under the proposed program, MSHA would sample multiple occupations on the same shift. This would provide a more comprehensive assessment of dust conditions to which miners are exposed.

• Since MSHA will be doing all the sampling, we 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 operator dust control program.

• Unlike the current sampling program, which allows operators control over when to sample and under what operating conditions, MSHA's visits 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.

• The miners' representative will have walkaround rights during sampling, thereby increasing miners' confidence in the dust sampling program.

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

Section 202(b)(2) of the Mine Act and the implementing MSHA regulations require 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 mg/m

. Under current MSHA regulations in §§ 70.101, and 90.101, the applicable coal mine dust standard is lowered further, by means of a formula (10 divided by the percentage of quartz) prescribed by 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.

This is based on the recognition that the toxicity of coal mine dust increases when higher levels of quartz are present. Consequently, as the quartz content of respirable coal mine dust present in the mine atmosphere increases over five percent, the applicable respirable coal mine dust standard is correspondingly lowered. For example, if 10 percent quartz was present, the mine operator would have to continuously maintain respirable dust at or below 1.0 mg/m

The applicable dust standard for intake air in § 70.100(b) and for miners who have exercised rights under part 90 regulations in § 90.100 is 1.0 mg/m

. Those standards are also lowered if quartz exceeds 5 percent. However, no effect occurs until the quartz content exceeds 10 percent.

The following provides an overview of MSHA's current and proposed revised procedures for arriving at an average quartz percentage that is used to establish an applicable dust standard.

1. Current Procedures

Until 1985, the applicable dust standard was adjusted based on the percentage of quartz determined from a single, full-shift (8 hours or less in duration) respirable dust sample taken by an MSHA inspector. Since MSHA sampled less frequently than we currently do, a reduced standard could remain in place anywhere from 12 to 24 months. During that period the level of quartz could have either increased or decreased significantly. As a result in December 1985, MSHA implemented the procedures in effect. This program, for the first time, enabled mine operators to participate voluntarily in the process of setting reduced dust standards. These procedures are contained in Chapter 1 of MSHA's Coal Mine Health Inspection Procedures Handbook.

The most significant program change involved the use of individual quartz percentages determined from one MSHA and, under certain conditions, up to two coal mine operator full-shift respirable dust samples, referred to as “optional samples,” to arrive at an average quartz percentage. It also provides for the automatic reevaluation of work areas and occupations on a reduced dust standard every six months.

Under the existing system, if an MSHA sample contains more than five percent quartz, an operator is afforded the opportunity to submit an optional sample. Provided it has sufficient weight gain (0.45 mg), the quartz content will be averaged with the MSHA sample when sample results do not differ by more than ± 2.0 percent, and the standard set accordingly. If an operator fails to submit an optional sample or it contains insufficient weight for analysis, the standard is adjusted based on the MSHA sample alone. Operators are afforded the ability to submit a second optional sample whenever sample results differ by more than ± 2.0 percent. All three results are then used to compute the average quartz percentage.

Also, in November 1994, MSHA refined its analytical procedure enabling us to analyze inspector low-mass respirable dust samples (0.100 to 0.449 mg) for quartz. Only those samples containing 25 micrograms or more of quartz were used in the standard-setting process. However, this change applied only to filters that were preweighed to 0.001 mg for use by MSHA enforcement personnel. It did not apply to operator-submitted optional samples, which were collected with filters preweighed to 0.01 mg, for which we required a minimum of 0.45 mg of dust to be analyzed for quartz. The ability to accurately analyze samples containing small amounts of dust reinforced MSHA's views about the severity of quartz exposures in some coal mining operations.

A review of MSHA data for FY 1999 shows that of the 778 entities (

i.e.,

MMUs, DAs, designated work positions (DWPs), roof bolters, and part 90 miners) (MSHA, Results of Quartz Sampling Operator Involvement, 1999) placed on an initial reduced standard as a result of an MSHA sample containing more than five percent quartz, 753 (96 percent) of the entities submitted an optional sample. One would expect the level of participation to be high since failure to respond would result in the setting of a lowered dust standard based on the result of the MSHA sample, which first triggered the standard-setting process. Of the 753 entities submitting an optional sample, 231 were afforded the ability to submit a second optional sample (Ibid.). Again, as expected, over 73 percent (170) of those 231 entities submitted a second optional sample, probably because doing so could reduce the quartz average quartz percentage used to establish the applicable dust standard. For comparison, in FY 1992, 93 percent of the operators afforded the opportunity submitted an optional first sample, and 82 percent of the operators given the opportunity submitted a second optional sample.

However, as the following data show, operator participation tended to decline significantly when operators were given the opportunity to submit samples involving established entities on reduced standards. Of the 1122 entities given the option to submit a sample, only 450 or 29 percent responded, compared to 96 percent for entities placed on an initial reduced standard. In 1992, 32 percent of the operators elected to participate.

2. Proposed Revised Procedures

Consistent with MSHA's decision to assume full responsibility for compliance sampling, the Agency is also proposing to rely only on MSHA samples as the basis for setting the applicable dust standard when quartz is present. As discussed below, while the proposed scheme reduces the burden and cost on mine operators to take and

submit optional samples, it does not diminish the protections afforded operators under the current program. It continues to consider temporal variability associated with quartz determinations by averaging three MSHA samples collected on different shifts. MSHA recently published a proposed “Program Policy Letter (PPL) on Samples Used to Determine the Respirable Dust Level When Quartz is Present” for public comment [64 FR 65671, November 23, 1999] whereby the applicable dust standard would be set based on the results of multiple MSHA samples. It proposes that mine operator samples would no longer be used in combination with MSHA samples to determine the average quartz percentage that is used to set an applicable dust standard. In the proposed rule, MSHA is adopting the sampling approach set out in the PPL. The proposed rule supercedes the proposed PPL, and consequently, the proposed PPL is withdrawn.

We believe that results under the proposed process will be more representative of the quartz level to which miners are exposed. Unlike the current process, which may cause a standard to be set based on the quartz content of a single MSHA sample, three valid MSHA samples would be used to set a reduced standard under the proposed revised procedures [64 FR 65671].

Since MSHA is sampling underground mines bimonthly and surface mines semi-annually, we 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 would also begin reporting quartz levels to the nearest tenth of a percent. This is intended to be more protective for the miner than the current truncation of results to a full percentage point.

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 proposed revised procedures, when an MSHA sample contains more than five percent quartz, we would average the percent of quartz present in three most recent MSHA respirable coal mine dust samples to set the applicable dust standard. If an MMU, DA, DWP, 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 proposed 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 an MMU is on a 1.0 mg/m

-standard (10 percent quartz). If the first MSHA sample contains 7.2 percent of quartz, the existing standard of 1.0 mg/m

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

>-standard (10 ÷ 11.1% = 0.9 mg/m

). For MMUs, DAs, DWPs, or part 90 miners not on a reduced standard, MSHA would collect and analyze three samples for quartz to determine if a reduced standard was warranted.

Under the proposed procedures, if the newly-established standard is lower than the one in effect, the new standard would 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 dust standard would become effective on the date of the notice.

As published elsewhere in today's

Federal Register

, MSHA is also proposing to take enforcement actions on the basis of inspector single, full-shift, respirable dust measurements. For entities on a reduced standard, MSHA would delay any 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 would be cited for violation of the applicable standard currently in effect. On the other hand, if the quartz content of the sample would cause the dust standard and the corresponding citation threshold value (CTV) to increase so that the single, full-shift measurement would no longer indicate noncompliance, no citation would be issued. This is illustrated by way of the following example.

For example, suppose that the MMU is on a 1.3-mg/m

standard and a single, full-shift measurement of 1.6 mg/m

is obtained. Since this measurement exceeds the applicable standard, the operator is in violation of the standard. However, analysis of the DO sample shows that the sample contained 6 percent quartz which, if used, would result in a 1.7-mg/m

standard. This indicates that the quartz level in the environment of the DO has changed, suggesting that the current standard may no longer be valid. Therefore, since the original measurement of 1.6 mg/m

is less than the 1.7-mg/m

standard that should have been in effect on the shift sampled, a citation should 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 may no longer be submitted for determining the applicable standard. It is our belief that the procedures being proposed for setting reduced standards should be more protective for the miners than those in effect. The proposed approach provides for stringent monitoring exposure to quartz which is consistent with Advisory Committee's recommendation that MSHA increase surveillance and reduce exposure to this serious health hazard.

As under the current program, if operating conditions should change following establishment of a lowered dust standard that affect the level of quartz in the working environment, mine operators or miners' representatives will be able to request MSHA to conduct a quartz reevaluation. In the absence of continuous monitoring, mine operators should be cautious in preventing overexposures when abnormal conditions (such as cutting rock to install an overcast or other frequent but short-lived events involving cutting of rock) are encountered between MSHA sampling visits.

3. Validity of Averaging Percentages

The average quartz percentage used to set the applicable dust standard for a particular sampling location or area of a mine is 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 the PPL (op cit.) 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 averaging method does not always result in a larger average quartz percentage value.

Table III-1.—For Two Scenarios, Using Alternate Methods, Percent of Quartz in Respirable Dust

Scenario I

Dust mass

SiO

mass

% SiO

Scenario II

Dust mass

SiO

mass

% SiO

1.7

0.136

1.7

0.17

1.0

0.04

1.0

0.08

2.5

0.3

2.5

0.15

MSHA's Method

Average of % SiO

= 8

MSHA's Method

Average of % SiO

= 8

Commenter's Method

Sum (SiO

Mass) ÷ Sum (Dust Mass) = 9.2%

Commenter's Method

Sum (SiO

Mass) ÷ Sum (Dust Mass) = 7.7%

These examples show that for situations where MSHA would have determined a quartz percentage of 8 percent, the commenter's method would yield 9 percent in one case and 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:

• Design a mine ventilation plan that effectively controls respirable dust under typical mining conditions;

• Implement the plan's dust control parameters when approved by MSHA before commencing production;

• Maintain the dust control parameters specified in the approved plan and to monitor their function and operation through required on-shift examinations; and

• Evaluate their effectiveness with bimonthly samples in order to provide reasonable assurance that the dust control parameters continue to function as intended.

To control dust in the work environment, existing § 75.370 requires mine operators to develop and submit ventilation plans that are designed to control methane and respirable dust in the mine to MSHA for approval. 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:

• The quantity and the velocity of the air current used to ventilate the MMU;

• The number, type, and location of water sprays;

• The pressure and quantity of water delivered by the sprays; and

• 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 fully describe all dust controls in use at the mine. If such information is not fully disclosed, it is impossible for MSHA to fully enforce the plan provisions and to determine when the MMU is out of compliance with the ventilation plan.

When an operator submits a proposed mine ventilation plan or revision in accordance with § 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 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 inspector sampling or, to a lesser extent and only under certain circumstances, by mine operator bimonthly sampling. Generally, MSHA 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, plans may be implemented which are later determined to be inadequate under typical mining conditions under the existing process.

1. Evaluating and Approving Plan Requirements for Respirable Dust Control

Under the current program, the effectiveness of the plan's dust control parameters is assessed through sampling of the DO and other occupations associated with the MMU. Since there is no requirement for verifying plan effectiveness, we have had to rely on samples that may not be representative of dust concentrations to which miners are exposed.

MSHA sampled annually at each underground mine until recently. The Agency now samples bimonthly in each underground coal mine. This increased sampling effort is part of MSHA's initiative to increase confidence in the federal respirable dust program and to eliminate simple CWP, PMF, and silicosis among coal miners. During sampling inspections, we monitor compliance with the applicable dust standard, measure the concentration of respirable quartz dust; and identify occupations other than the DO that the mine operator should routinely monitor because they are at risk of exposure to excessive concentrations of respirable dust.

Under current inspection procedures, MSHA inspectors sample at least five different occupations, if available, on each MMU on each shift. Samples are normally taken under the mining conditions in effect during sampling. In conjunction with this sampling, the MSHA inspector checks and measures the dust control parameters early in the shift to determine whether the ventilation plan is being followed. The inspector records the findings, and all

the dust controls and work practices in use during sampling on MSHA Form 2000-86 (Revised),

Respirable Dust Sampling and Monitoring Data

. MSHA will issue a citation if the mine operator fails to follow any of the dust control parameters specified in the plan. Normally, the citation requires immediate corrective action to abate the violation. This may involve, for example, unplugging some water sprays or increasing the amount of ventilating air delivered to the MMU. At the conclusion of the sampling shift for an MMU, the inspector determines the total amount of material that was mined (in tons) during the shift.

If the average concentration of the samples taken in one shift is less than, or equal to, the applicable standard, and the actual production is at least 60 percent of the average production over the last 30 production shifts, the MSHA inspector will normally terminate sampling after the first day and will recommend that the plan parameters be approved by the District Manager. This would occur even if the samples were found to contain more than 5 percent of quartz. Such a finding could result in MSHA lowering the dust standard below that in effect at the MMU. Since 1985, MSHA has provided mine operators the opportunity to participate in the process to establish a lower dust standard based on the level of quartz. Mine operators can submit up to two optional samples which are averaged with the MSHA sample to determine the average percentage of quartz which is used to establish a new dust standard for the MMU. MSHA published a proposed Program Policy Letter for comment (64 FR 65671, November 23, 1999) whereby the standard would be determined based solely on the results of multiple MSHA samples. Under that proposal, mine operator samples would no longer be used to calculate a reduced dust standard. Instead, applicable dust standards will be set based solely on the results of MSHA samples.

If the average concentration falls below the standard in effect, but one or more samples exceed it, no decision is made regarding the plan's effectiveness or regarding compliance with the applicable standard. Instead, the inspector must collect additional samples on subsequent production days or shifts to establish that the dust control provisions of the ventilation plan are adequate.

To a lesser extent, if MSHA is unable to schedule a mine visit within the period established by the individual district, the District Manager may rely on the results of operator bimonthly sampling to approve a plan. Generally, this occurs in the case where a plan is upgraded with a change which has been established as effective. MSHA does not routinely approve plans based on operator bimonthly sampling because these samples may be collected during periods when production is not reflective of typical production levels. The current program permits the operator to submit samples which may not be representative of normal dust conditions in the working environment. Under current regulations, operator bimonthly samples will be considered valid, unless voided by MSHA, when the MMU produces at least 50 percent of the average level reported for the last set of five valid bimonthly samples. Since a mine's “normal production” level for sampling purposes and the typical production level may diverge greatly over the course of several sampling periods, granting approval under these conditions may not reflect the plan's effectiveness under more typical mining conditions.

2. Compliance with Plan Requirements for Respirable Dust Control

Once MSHA determines that the dust control measures are adequate and approves the mine ventilation plan, the specified dust control parameters are to be employed on a continuous basis to safeguard the health of miners. Since maintaining the approved dust control parameters provides reasonable assurance that respirable dust can be controlled, failure to comply with these requirements would defeat the purpose of the mine ventilation plan and needlessly expose miners to excessive concentrations of respirable dust. Section 75.362 requires mine operators to perform an on-shift examination of the dust control parameters before the MMU begins production in order to assure full compliance. Any deficiencies must be corrected before production begins.

Compliance with approved plan parameters is checked during MSHA's routine sampling inspections: as part of six-month plan reviews, during other non-sampling inspections or investigations, or in conjunction with an ongoing sampling inspection.

3. Monitoring Effectiveness of Plan Requirements for Respirable Dust Control

Because of the dynamic nature of mining, conditions can change significantly in a short period of time. For example, an increase in the concentration of respirable quartz dust will require the applicable standard to be reduced below the level that was effective when the dust control parameters were first evaluated. Such changes can directly impact the effectiveness of the dust-control measures. It is important to regularly monitor the adequacy of the approved dust control requirements to ensure that they remain suitable for the current conditions at the mine and to determine whether the plan should be upgraded. Currently, both MSHA and the mine operator regularly monitor the operator's dust control program. However, for MMUs the mine operator is responsible for making sure that all provisions of the ventilation plan are in effect on every shift.

(a)

Monitoring by Mine Operators

. Since 1980, the current regulations have required mine operators to take five valid samples from the DO in each MMU on a bimonthly basis and submit them to MSHA for processing, to determine compliance with the applicable dust standard. Section 70.207(e) identifies the DO for each method of mining. These are collected either on consecutive normal production shifts, or on production shifts worked on consecutive days, during which the amount of material produced by the MMU is at least 50 percent of the average production reported for the last bimonthly sampling period. These samples must be collected portal-to-portal during the entire shift or for 8 hours, whichever time is less.

Bimonthly samples have provided a periodic evaluation of the quality of the air miners breathe. They also have provided some insight into the effectiveness of the operator's dust control system on the days in which the samples are taken. Mine operators may exceed their minimum plan requirements once they have been approved as effective under current evaluation criteria. Currently, there is no requirement for mine operators to record the dust control measures in use as part of the on-shift examination. Because there is no requirement for such records, MSHA cannot assess the continued adequacy of the approved dust control requirements unless the inspector observes the sampling process.

Although the current operator sampling program may limit the utility of bimonthly samples for plan approval purposes, they allow MSHA to identify approved plans that may no longer be suitable to the conditions at a mine. If multiple individual samples, or their average, exceed the applicable dust standard after the required on-shift examination has been conducted, the approved plan parameters may no longer be effective and may need to be upgraded. If cited, the operator must

take corrective action to lower the concentration of respirable dust to within the permissible concentration as described in current § 70.201(d). The operator must demonstrate, through sampling, that the underlying condition(s) which caused the violation has been corrected. Since MSHA inspectors are not present to observe the action(s) taken by the operator to abate the violation, the ventilation plan is usually not amended to include the changes the operators make to the parameters in order to abate the violation. However, if the operator has a record of noncompliance and MSHA determines that the approved plan parameters may no longer be adequate, MSHA will notify the operator to submit an improved plan. Under current plan approval procedures, if the operator fails to address MSHA's concerns after receiving the second notification, MSHA will move to revoke the operator's mine ventilation plan. If the plan is revoked, the mine must not operate.

As discussed earlier, MSHA is proposing to revoke operators' sampling program in underground mines and assume full responsibility for all compliance sampling.

(b)

Monitoring by MSHA

. One of the objectives of MSHA's dust sampling program is to verify that the controls specified in the approved mine ventilation plan continue to control concentrations of respirable dust under existing mining conditions. As part of this program, the dust control parameters must be checked and measured early in the shift to assure compliance with the approved plan. These checks also verify that the operator is performing the required on-shift examinations. Operators have the opportunity to adjust their dust controls to reflect that which has been approved so the plan can be evaluated. However, most operators choose not to make adjustments for a number of reasons. While inspection procedures require the ventilation plan to include the dust control measures in use during the evaluation, most approved plans do not incorporate all the measures that were actually in place during MSHA sampling. This makes it difficult for MSHA to assess the continued adequacy of the approved dust control parameters. Frequently, decisions must be based only on prior experience or engineering judgment.

When an operator is cited based on MSHA samples, the inspector may require the operator to describe what type of corrective action will be taken. However, if a plan change is required, MSHA must follow similar plan approval procedures. The operator must be notified in writing that the plan is inadequate. In this case, MSHA has sample results and a record of the actual parameters in place which can be used to document the need for a plan change. Most plans which are revised simply incorporate only those dust controls that were in use when MSHA sampled.

MSHA reviews each mine ventilation plan every six months under § 75.370. The review includes: all plan revisions, respirable dust inspection reports, citations for exceeding the applicable dust standard, and comments from representatives of miners. When a deficiency in the respirable dust control portion of the plan is found, the MSHA inspector records comments on MSHA Form 2000-86. MSHA sends these results to the mine operator along with an explanation of whether the operator must make any changes, the reasons for the changes, and the date for submitting a plan revision. MSHA will send a second notification if the operator fails to respond. MSHA may revoke the operator's mine ventilation plan if the operator does not comply.

4. 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's proposal makes a number of changes to the process for evaluating, approving, and monitoring mine ventilation plans, many of which are based on the Advisory Committee's recommendations.

Consistent with the Advisory Committee recommendations, MSHA proposes to add provisions to verify the effectiveness of the ventilation plan in controlling dust, at a production level high enough to demonstrate the plan's effectiveness under typical operating conditions. This would require that MSHA implement procedures for reviewing compliance and production records. It would also require that dust control parameters and production associated with samples on a given shift be recorded in order to demonstrate that parameters specified continue to be effective in controlling dust.

This proposal would require 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 current program, you would have to identify all measures necessary for achieving continuous compliance with the applicable dust standard in the plan.

MSHA proposes to require you to include information on the length of each normal production shift in § 75.371(f) and to specify the VPL as defined in § 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 would require you to maintain records of the amount of material produced by each MMU during each shift. This would enable you 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 higher-than-average production. Although a VPL would be included in the ventilation plan, MSHA would not cite you for producing at levels exceeding the VPL.

Under the proposed plan verification procedures, MSHA will notify you of when we intend to initiate verification sampling. To enable MSHA to evaluate the effectiveness of the plan parameters at or above the VPL, you must make sure that all the dust control parameters specified in your ventilation plan are fully implemented. On the date scheduled for verification sampling, you should arrange to be producing at or above the VPL specified in the plan, using only the dust control parameters and other measures listed in the plan.

Under the proposal, MSHA would perform the sampling necessary to verify your plan. We will collect full-shift samples from the work environment of multiple occupations on each MMU, including the DO. We will collect all samples in accordance with procedures described in Chapter 1 of MSHA's Coal Mine Health Inspection Procedures Handbook (op cit.). In addition, on every shift on which we

collect verification samples, we would measure and record all of the quantitative engineering or environmental parameters. We would also record any other means used to reduce miners' dust exposure on the sampled shift. We will provide you with this information, along with verification sample results, for posting on your mine bulletin board.

In accordance with section 103(f) of the Mine Act, you must provide miners and their representatives the same walkaround rights during plan verification sampling as they are provided during any other physical inspection made pursuant to the provisions of section 103(a) by an authorized representative of MSHA.

MSHA believes that under the guidance of the Interpretive Bulletin 43 FR 17546 (April 25, 1978) these 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.

Verification sampling is necessary to obtain information related to approval of the mine's ventilation plan and whether coal mine dust will be adequately controlled to protect miners health. Consequently, miners and their representative would have the right to accompany the inspector with no loss of pay for the time during which the representative exercises this right. However, this right is limited by Section 103(f) to only one such representative of miners.

Unlike the existing program, the proposal would allow you, for the first time, to use either approved PAPRs or verifiable administrative controls to supplement your engineering or environmental controls for compliance purposes at longwall mining operations. This would be permitted only on an interim basis and only after MSHA determined that you had exhausted all feasible engineering or environmental controls.

Finally, under this proposal, MSHA has established rigorous criteria for determining when to approve a plan. We 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.

Hierarchy of Dust Controls

Consistent with the Mine Act, engineering or environmental controls have been the principal method used for preventing or minimizing miners' exposure to these primary and secondary dust sources in the workplace over the past 30 years. Control of dust throughout the work environment gives 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 insure that they are functioning as intended. 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. 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 not only recognized by the Advisory Committee, but also by NIOSH in its criteria document:

Occupational Exposure to Respirable Coal Mine Dust

(NIOSH, 1995), when it 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 is preserved under this proposal. The proposal requires mine operators to utilize all feasible engineering or environmental controls to reduce concentrations of respirable dust to a level at or below the applicable standard.

Administrative controls are another method of avoiding overexposure. Administrative controls refer to work practices that reduce 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 operator, or the occupation designated as 044 by MSHA. This particular form of administrative control is 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 Advisory Committee Report states 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 standard. However, the 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).”

Under the Mine Act and current regulations, mine operators are required to make approved respiratory equipment available to all affected underground miners whenever exposure to concentrations of respirable dust exceeds the applicable dust standard. However, miners are not compelled to use them. While required for interim protection, mine operators cannot use respirators as a substitute for engineering or environmental control measures. Engineering or environmental controls have been found to provide more consistent and reliable protection to all workers. In comparison to respirator programs, the effectiveness of engineering or environmental controls does not rely heavily upon constant supervision or miners' consistent and correct use of the equipment. Furthermore, we can measure dust concentrations to which miners are exposed when engineering or environmental controls are in use. It is more difficult to monitor the effectiveness of a respirator program because the assessment methods are indirect. For these reasons, MSHA's longstanding policy has been that respirators should be used in underground coal mines only as an interim method of protection until feasible engineering or environmental controls are available.

Approved respirators are not acceptable substitutes for feasible engineering or environmental controls.

It is MSHA's position that technology is available to control respirable dust to at or below the applicable standard at MMUs employing continuous and conventional methods of mining. However, MSHA recognizes that, unlike other mining systems, longwall MMUs may have acute dust problems caused by the face-ventilation airstream carrying the shearer-generated face dust over the miners working along the face downwind of the shearer operator (occupation code 044). This makes it more difficult to control the work environment 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 five-fold since 1980, from approximately 890 tons per shift (tps) to more than 4,900 tps in 1998. 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 history 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, most of these particles do not become airborne. Nevertheless, given the amount of dust that is produced per ton of coal mined, a larger quantity of respirable dust would be generated from cutting 8,000 tons of coal than from cutting 4,000 tons. An operator is not required to produce, on a sampled shift, more than 50 percent of the average production reported during the last bimonthly period. Therefore, dust concentrations on sampled shifts may be substantially lower than what is typical and therefore not reflect the dust exposure on that shift.

While significant efforts have been made to implement available control technology, no significant new advancements in longwall control technology have been reported since 1989 (U.S. Bureau of Mines, undated). From 1989 to 1999, the percentage of operators' longwall DO samples exceeding 2.0 mg/m

dropped from 34 percent to 20 percent, reflecting the impact of the implementation of those advances in longwall control technology. Although this represents a significant improvement, especially in view of the five-fold increase in average shift production, the 1999 data clearly show 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, such a study has never been undertaken because no industry partner has agreed to participate. Based on our experience, MSHA's position remains that feasible engineering and environmental controls exist for maintaining dust exposures at or below the applicable standard, even at longwall operations. MSHA has concluded that the proposed plan verification process will lead to further improvements in the design and quality of mine ventilation plans. At some high-producing longwall MMUs, however, the engineering or environmental controls available may not succeed in sustaining continuous compliance with the applicable dust standard at certain locations downwind of the longwall operator (occupation code—044).

Mining industry representatives have repeatedly urged MSHA to accept the use of powered, air-purifying respirators (PAPRs) (

e.g.,

Racal® Airstream helmets),

as an alternative means of complying with the applicable dust standard when engineering or environmental controls failed or were not feasible. The Airstream helmet originated in the early 1970s at the Safety in Mines Research Establishment in England which developed it primarily for mining use to provide protection for head, eyes, and lungs in a single convenient unit. Because these devices provide a continuous stream of filtered air over the miner's face, it has been suggested that they be viewed as miniature environmental controls, rather than respirators. In September 1997, Energy West Mining Company (Energy West) petitioned the Secretary of Labor to amend the mandatory health standards for underground coal mines at 30 CFR part 70 to allow Airstream helmets or other types of PAPRs to be used as a supplemental means of complying with the applicable dust standard. The petition for rulemaking proposed that the Secretary issue a standard which would supersede the current interim statutory standard, specified in Section 202(h) of the Mine Act. Energy West contended that PAPRs are necessary as a supplemental means of controlling respirable dust because even the most diligent application of feasible engineering/environmental controls could not always prevent overexposure. MSHA has consistently acknowledged that PAPRs can be effective as an interim method of protecting miners when properly selected, used, and maintained. However, MSHA has never considered the Racal® Airstream helmet (or the 3M

Airstream

Helmet-Mounted PAPR), or any other respiratory protective device approved and labeled as such by the National Institute for Occupational Safety and Health (NIOSH), to be an engineering, environmental, or administrative control. Hence, it cannot be used as an environmental control to comply with the respirable dust standard.

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

In order to provide the greatest possible protection for all miners under typical mining conditions, MSHA is proposing to permit, under certain circumstances, the limited use of either approved loose-fitting PAPRs or verifiable administrative controls for compliance purposes. This would provide you with the flexibility to select the most appropriate option for supplementing your engineering or environmental controls. We believe that permitting longwall mine operators to use loose-fitting PAPRs or verifiable administrative controls for compliance purposes will not reduce the level of protection afforded longwall miners by the existing standard.

This aspect of the proposal is limited to longwall mine operations because technology is available to control respirable dust at or below the applicable standard at MMUs employing continuous and conventional methods of mining. Their use at longwall operations would be permitted

only after MSHA determines that for a specific MMU, excessive dust concentrations cannot be prevented in the environment of miners required to work downwind of the longwall shearer operator (occupation code—044) by implementing all feasible engineering or environmental controls. We solicit comments concerning the availability of feasible engineering or environmental controls to lower dust levels.

1. Selection of Respirators: Loose-Fitting PAPRs

Loose-fitting PAPRs completely surround the head and cover the face with a full visor or shield. The functional and physical characteristics of loose-fitting PAPRs as described below make them especially well-suited to underground coal mining conditions, and it is for these reasons that MSHA determined that loose-fitting PAPRs are the most suitable type of respirator protection for these conditions.

A loose-fitting PAPR protects the wearer from excessive levels of respirable dust by providing a continuous flow of filtered air and imposing minimal breathing resistance upon the wearer. Loose-fitting PAPRs do not require fit-testing,

6 7

unlike tight-fitting respirators. Furthermore, it is not necessary to be clean shaven for this type of PAPR to be protective.

6 7

Quantitative fit testing and qualitative fit testing are methods used to determine the facepiece seal and fit of a tight-fitting respirator.

Loose-fitting PAPRs provide safety advantages over other forms of PAPRs or tight-fitting respirators. In addition to protecting the lungs, the helmet and visor of a PAPR can simultaneously protect the eyes and head from high-velocity nuisance dust, spray, and small pieces of coal from the cutting drums and face and from loose coal falling from the roof. Loose-fitting PAPRs provide easier communication between miners, rather than the muffled communication between workers which is experienced between miners wearing tight-fitting facepieces.

The Racal® Airstream helmet has been in use in underground coal mines since the late 1970s. Over 50 percent of the longwall mines operating have miners who wear Airstream helmets for added protection. This respirator was developed primarily for mining use by the Safety in Mines Research Establishment (SMRE) in England. It combines face, head, and respiratory protection in a single convenient unit. The support hardware which provides the filtered air is packaged in the helmet. Power for the system is provided by a belt-mounted battery. Dusty 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, and exits at the chin. Soft plastic seals join the face-shield visor to the sides of the head and jaw limiting entry of unfiltered mine air (Greenough, 1979). The original Airstream helmet has undergone numerous design improvements since it was first introduced in British coal mines in the mid 1970s. The Airstream helmet is produced by 3M (3M

Helmet-Mounted Airstream

series).

2. Protection Factor for Loose-fitting Powered, Air-Purifying Respirators

The type and degree of protection of any respirator depends on the ability of a respirator to prevent hazards from entering the worker's breathing zone. In an underground coal mine, the level of protection afforded by a loose-fitting PAPR to protect a miner depends on the type and condition of the filter material of the air-purifying element, the nature and concentration of the respirable coal mine dust, proper maintenance of the PAPR and battery pack, and especially, how consistently the miner properly wears the PAPR, including having the visor properly lowered. The protection factor, the ratio of the respirable dust concentration outside the respirator to the concentration inside, measure how much protection a respirator might provide to the wearer.

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 loose-fitting, 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 caveat 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 invade the miners' breathing zone through openings along the side and bottom of the visor, even when it is maintained in the full lowered position. The extent to which respirable dust invades a miner's breathing zone, depends, in part, on the MMU's ventilation air velocity and on the miner's work rate and his angle of orientation to the airflow.

Questions have arisen concerning the applicability of NIOSH's APF of 25 for loose-fitting PAPRs to some work environments. It has been contended that NIOSH overestimates the minimum level of protection provided in the workplace even when used within the context of a good respirator program (Myers,

et al.,

1984). The environmental conditions assumed in NIOSH's estimation of the APF for loose-fitting PAPRs are not consistent with those in underground longwall mining operations. For example, various unique conditions of coal mining (obstructed views and difficulty communicating) may 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. Also, the high velocities of air customarily found on longwall mining faces, 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. 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 protection provided in the workplace. Unlike an APF, an effective protection factor (EPF) reflects the protection provided by a respirator over an actual work shift given specific occupational environmental conditions such as ventilation velocity, when the wearer performs typical work activities and uses the respirator in a typical manner.

Laboratory and in-mine studies (EPF studies) show that mine ventilation air flow or velocity, the primary means

longwall operators use to control respirable dust levels, may be the single biggest factor affecting the level of protection provided by the PAPR on a longwall mining face. Cecala,

et al.

, (1981) found protection of loose fitting PAPRs (Racal® 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 level of protection from a loose-fitting PAPR is also affected by the orientation of the helmet to the airflow. Cecala's wind tunnel tests clearly showed that, at the higher flow 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 loose-fitting, helmeted PAPRs produced an EPF confirming the inverse relationship between wind speed and the level of protection provided by PAPRs shown during wind tunnel testing. Air velocity in underground mines is measured in units of feet per minute (fpm). Under normal face-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 high face-velocity conditions (1,200 fpm), the helmet's dust reduction efficiency decreased significantly, averaging only 49 percent, which is equivalent to an EPF of 2.

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 protection factor of 6.3. This met the target protection factor 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 medium-velocity western longwalls indicated loose-fitting PAPRs had an average dust reduction efficiency of 83.8 percent (Ibid.). Although a different sampling procedure was used, this result is consistent with the average value of 84 percent obtained by Cecala,

et al.,

under normal mine face-velocity conditions. During the test period, the headgate velocity ranged from 345 to 500 fpm, with approximately 88 percent of the recorded velocities falling below 500 fpm. The tailgate velocities ranged from 280 to 550 fpm and only one exceeded 500 fpm. No tests were conducted under high mine face-velocity conditions.

The headgate and tailgate velocities observed by MSHA inspectors at 55 longwall MMUs were reviewed in 1999. The headgate and tailgate 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.

PAPRs have been demonstrated to be effective on longwall MMUs when air velocities do not exceed 500 fpm, but, as described above, there is evidence that their effectiveness is reduced when air velocities are increased. Therefore, given the range of observed longwall face air velocities to which miners are exposed and the proposed requirement that the verified ventilation plan demonstrate that the longwall shearer operator (occupation code—044) be at or below the applicable standard, MSHA is proposing to grant a protection factor of two for loose-fitting PAPRs used under this proposal. Multiplying either the respirable dust standard or the verification limit (whichever is applicable) by the protection factor yields the maximum concentration of respirable dust against which a particular type of respirator can be used. In other words, if MSHA permits a longwall operator to use PAPRs, then the maximum concentration of respirable coal mine dust and quartz dust against which these particular respirators can be used are 4.0 mg/m

and 200 μg/m

, respectively. A complete respiratory protection program is required to assure that a respirator's protective value is not compromised by improper fitting or usage.

MSHA's determination is based on the best scientific and technical information available as well as sound engineering judgment. However we encourage you to submit comments on the protection factor. We are particularly interested in obtaining more recent data that may be available concerning protection factors as well as the conditions for the use of PAPRs. If you believe MSHA should establish a different protection factor, please submit these data supporting your position.

E. Guidelines for Determining What Is a Feasible Dust Control

The proposal would require a mine operator to implement all feasible engineering or environmental controls that are technologically and economically feasible. 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

Callanan Industries, Inc.,

5 FMSHRC

19 00 (1983), and Secretary of Labor

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 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 proposed § 70.211 in Section IV of the

proposal, 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 would be made by the Administrator for Coal Mine Safety and Health based on the best available information, experience, and engineering judgment.

F. Application of Continuous Monitoring Technology to Prevent Overexposures on Individual Shifts

Because approved technology that continuously monitors respirable dust and displays dust concentrations in real-time is not available, effective ventilation plans remain the only practical means to provide reasonable assurance, on a continuous basis, that miners are not overexposed on individual shifts. However, MSHA recognizes that person-wearable continuous respirable dust monitors under development may lead to significant improvements in monitoring the work environment in order to improve miner health protection. In an effort to reduce occupational respiratory disease among underground coal miners, MSHA encourages mine operators to adopt new and better dust monitoring technology as part of the approved ventilation plan.

Unlike the current monitoring system, which relies on periodic sampling and requires that corrective action be taken after the necessary delay in obtaining dust level information, continuous monitoring would allow mine operators and miners to be aware of the actual dust conditions at all times, thereby enabling immediate action to avert possible overexposure. The ability to monitor dust exposure continuously during the shift, predict end-of-shift cumulative exposures, and to display the actual end-of-shift exposure would be far more effective in preventing simple CWP and PMF than the current system.

The health benefits of continuous monitoring were clearly recognized by both the Task Group and the Advisory Committee. Both recommended development, field testing, and immediate deployment of such monitors for a variety of purposes. The Task Group concluded that continuous monitoring of the mine environment and dust control parameters offered the best long-term solution for improving the existing federal program designed to prevent simple CWP and PMF among coal miners. Similarly, the Advisory Committee stated in its report 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 availability of this information on a real-time basis would enable mine personnel to focus attention immediately on the need to adjust control parameters to avert possible overexposure. The recent development of continuous dust and continuous dust control parameter monitors, which have both direct reading and data recording/processing capabilities, offers the potential to improve monitoring of the work environment significantly and contribute to the effective control of exposure. (MSHA, 1996).

MSHA has sought a means to measure the concentration of respirable coal mine dust in coal mines on a continuous basis for nearly two decades. Beginning in the 1970's, at the request of MSHA, the former U.S. Bureau of Mines funded several developments of fast-response, direct-readout respirable dust monitors for measuring the concentration of respirable dust.

One type of fast-response respirable dust monitor determined the mass of respirable dust particles collected on a grease-coated disk by the attenuation of beta radiation caused by the dust spot on the impaction disk. The unit was capable of operating for long periods, taking up to 450 1-minute samples, and printing the individual and time-integrated concentrations on a tape.

Other devices have used light-scattering technology to measure and provide an immediate direct readout of dust concentrations. Since light scattering is often dependent on particle characteristics such as size, surface properties, and refractive index, this type of dust monitor does not measure a mass concentration directly and can provide only a relative measurement. However, it can be calibrated in the laboratory to give an approximate mass concentration.

The light-scattering technology was later incorporated in a machine-mounted, continuous respirable dust monitor for use in underground mines. In the early 1980's, however, it was determined that this technology was not effective for monitoring compliance with the applicable dust standard. Nevertheless, instruments which used the light scattering principle were found to be useful tools to locate dust sources and to determine its magnitude. Such instruments continue to be especially useful for evaluating dust-control techniques such as dust collectors and water sprays that can be turned on and off quickly and repeatedly.

The 1992 Task Group report recommended the accelerated development of a fixed-site underground dust monitor, capable of providing continuous information on dust levels and personal sampling devices capable of providing both short-term and full-shift exposure measurements. In response to this recommendation, the former Bureau of Mines, with MSHA's assistance, again evaluated existing technology that could be used in the development of a fixed-site underground mine dust monitor. This was made possible because of advances in sensing and electronic signal processing technology that had occurred since development of the first generation machine-mounted dust monitor in the late 1970's. Eventually a fixed site/machine-mounted continuous respirable dust monitor based on the proprietary mass-measurement technology known as the tapered element oscillating microbalance (TEOM®) was developed and field tested.

The TEOM technique is capable of continuously weighing a filter upon which dust is collected. It provides a real-time record and a permanent record of the total mass collected on the filter. The device can display the time-weighted average (TWA) concentration of respirable coal mine dust (total mass of dust collected divided by the length of time the unit was operated), the instantaneous (real-time) concentration, and the projected full-shift concentration. This would allow a mine operator to adjust control measures or optimize mining procedures to prevent miner overexposure. The full-shift concentration of respirable coal mine dust would be available at the end of the shift. The developer of the fixed-site monitor is also working on a person-wearable, end of shift/continuous respirable dust monitor using the same TEOM technology.

In addition to the TEOM technology, NIOSH is developing another person-wearable device that has the potential for continuously monitoring the mine environment. This device measures the mass of respirable dust indirectly based on the amount of pressure drop detected across the collection filter.

MSHA is seeking ways to encourage voluntary deployment of this technology, once it has been verified as reliable. MSHA has considered allowing mine operators to adopt a continuous personal monitoring strategy as part of the approved ventilation plan, in lieu of plan verification. Under this approach, the operator would have the flexibility of choosing from several technologies available for continuous personal monitoring. If an operator adopts continuous personal monitoring, the following additional information, at a

minimum, would be required for the mine ventilation plan:

1. The specific continuous personal monitoring device the operator intends to use which has been approved by the Secretary;

2. The DO and other occupations or individuals, including part 90 miners, that will be sampled on every production shift and the length of the production shift to be sampled;

3. The procedures for preventing exposure above the applicable dust standard;

4. The manufacturer's calibration and maintenance requirements, and a description of how records of calibration and maintenance will be made available to MSHA, miners and the miner's representatives; and

5. A description of how end-of shift measurements will be recorded, who will certify that such records are accurate and properly taken, how long such records will be maintained, where such records will be made available for inspection by MSHA, miners and the miner's representatives, and how miners will be notified on each production shift of the end-of-shift measurements.

At the present time, we do not believe that technology to enable continuous monitoring of respirable dust has advanced to the point where it could be relied upon as an alternative to plan verification. In the future, when this technology is available, MSHA will consider the implementation of such an alternative to the proposed plan verification program. We request comments on this approach as a possible alternative to plan verification. MSHA is specifically interested in any proposals for the use of continuous personal monitoring, as well as any information which may be available concerning developing technology. Should an operator be interested in implementing a continuous personal monitoring program at a specific mine, MSHA will review the plan and consider development of a pilot program to develop information which may be useful for future rulemaking. MSHA is interested in comments concerning the specific provisions which should be included in the ventilation plan to assure that, if an operator does develop a continuous monitoring program, miners will not be overexposed on any individual shift.

IV. Discussion of Proposed Rule

A. Summary

As recommended by the Advisory Committee in 1996, MSHA is proposing to assume responsibility for all compliance sampling for respirable dust in underground coal mines as required under CFR parts 70 and 90. This proposal includes revocation of bimonthly compliance sampling requirements, abatement sampling requirements, the process for establishing a reduced standard when quartz is present, and operator sampling requirements for miners who have evidence of the development of pneumoconiosis under part 90. In order to provide a greater level of protection than that provided under these sampling requirements, MSHA is proposing to require each underground coal mine operator to have a verified mine ventilation plan. Under this proposal, MSHA would verify the effectiveness of the mine ventilation plan for each mechanized mining unit (MMU) in controlling respirable dust under typical mining conditions.

Mine ventilation plans have long been recognized as a means of addressing mine-specific health and safety issues. Existing § 75.370 requires that each mine operator design a ventilation plan to control methane and respirable dust in the mine. It further requires that the plan be suitable to the conditions and mining system at the mine. However, there is no current provision requiring the effectiveness of mine ventilation plans to be verified under typical mining conditions.

Since 1970, beginning with enforcement of the Federal Coal Mine Health and Safety Act of 1969, the level of respirable dust in underground coal mines has been significantly reduced. Although much progress has been made, MSHA sampling data indicate that some work environments continue to have excessive concentrations of respirable dust. It is MSHA's position that excessive dust levels can be substantially reduced, if not eliminated, by implementing the Advisory Committee's recommendations to enhance plan quality and strengthen the plan approval process. Toward this end, this proposal would revise 30 CFR by revising part 70, subparts A, B, and C amending two existing sections of part 75.

This proposal would require evidence that the mine ventilation plan is effective in controlling respirable dust as required by § 75.370. Within the first 30 days of operating a new MMU, or when required to do so by the District Manager, mine operators would have to specify the operating parameters of an effective plan and then MSHA would verify the plan's effectiveness based on a sufficient number of full-shift samples taken at designated locations.

Under this proposal, we would collect full-shift respirable dust samples, called “verification 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 2.0 mg/m

and 100

g/m

, respectively.

For purposes of plan verification, “full-shift” would refer to the entire work shift during which material is produced by an MMU. Currently, many mining operations have work shifts of more than 8 hours. Miners working extended shifts should be protected from the hazards of respirable dust and quartz by the ventilation plan. Accordingly, the proposed verification samples would not be limited to 8 hours or less, as under the current bimonthly operator sampling regulations.

A sample would be valid for verification purposes only if the shift on which it was taken met certain requirements. This is necessary in order to verify that dust controls specified in the plan are sufficient to prevent excessive dust concentrations, even when a higher-than-average amount of material is produced. The proposed operator's requirements for a shift used for verification sampling are:

(1) The dust controls and work practices utilized must be those listed in the mine ventilation plan;

(2) MSHA's measurements of the engineering or environmental control parameters must not exceed 115% of the quantities specified in the plan; and

(3) The amount of material produced must be at least the “verification production level” or VPL.

The VPL is defined as the tenth highest production level recorded in the most recent 30 production shifts.

The proposed rule would require mine operators to: (1) Set and maintain the dust control parameters during MSHA verification sampling at levels specified in the plan; (2) maintain and make available to MSHA records of the amount of material produced by each mechanized mining unit during each production shift; and (3) provide additional information in mine ventilation plans.

The number of samples necessary to verify that the dust control parameters proposed for an MMU are effective would depend on the individual sample. Since all such measurements are subject to potential sampling and analytical errors, some of them may fall slightly below the verification limit even when the true concentration of respirable coal mine dust or quartz 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” established by MSHA provide this margin of error. If the VPL is achieved and dust concentrations are sufficiently low, the District Manager could approve a plan based on as few as one shift of sampling. However, if dust concentration measurements are higher, or if the actual production was less than the VPL MSHA would sample additional shifts.

Consistent with the Mine Act and its implementing regulations, MSHA's longstanding policy has been to preserve the primacy of engineering controls, to the extent that they are technologically and economically feasible. Consequently, MSHA has not accepted the use of approved respiratory protection or administrative controls as a means of achieving compliance with the respirable dust standard. In order to provide all miners with the highest possible level of health protection, as intended by the Mine Act, MSHA is now proposing to permit the use of approved PAPRs or verifiable administrative controls to supplement engineering or environmental controls under certain circumstances for compliance purposes. Their use would be limited to longwall mining operations and permitted only after MSHA has determined, upon request of the operator, that all feasible engineering or environmental controls cannot maintain the mine atmosphere within applicable standards. In such cases, specific requirements governing the use of PAPRs or verifiable administrative controls would be specified in the mine ventilation plan.

Finally, the proposal would require you to maintain, and make available to MSHA inspectors, records of the amount of material produced by each MMU during each production shift over a running six-month period. This, along with routine bimonthly and other sampling data, would enable us to review the suitability of the plan parameters on an ongoing basis.

Although a VPL would be included in the ventilation plan, we would not cite you for producing at levels exceeding the VPL. We would expect production on an MMU to exceed the VPL on about 33 percent of all production shifts. If the District Manager determines that your production exceeds the VPL on more than about 33 percent of the production shifts over a six-month period, then this may trigger the plan verification process using a higher VPL.

These and other provisions of the proposed rule are explained in more detail in the following section-by-section discussion.

B. Section-by-Section Discussion

This section of the preamble explains, section-by-section, the provisions of the proposed rule. The text of the proposed rule is included at the end of the document.

Section 70.2 Definitions

The existing definitions of certified person, concentration, and designated area (DA) are being modified to more clearly convey the intended meaning under the proposal. These modifications reflect necessary changes as a result of the removal of existing paragraphs and the transfer of other paragraphs, as well as the addition of new references. The proposal also includes definitions of new terms to clarify the mine ventilation plan verification process as it applies to mechanized mining units (MMUs). Some of the definitions are for technical terms developed specifically for this proposal, such as “verification limit” and “verification production level.” Finally, the definitions of “certified person,” “normal production shift,” and “valid respirable dust sample” would be removed.

We explain these new and revised definitions of terms below. You should also closely examine each proposed section where the term is used to review the context in which it is used.

The following existing definitions are being modified:

Concentration

The existing definition would be modified so that “concentration” refers to an 8-hour Mining Research Establishment (MRE) equivalent measure of the amount of sampled material contained per unit volume of air. The proposed revision would include the constant factor of 1.38 which the Secretary currently uses to convert concentration of respirable dust measured with approved sampling devices to an equivalent concentration as measured with an MRE instrument.

MSHA developed the existing coal mine dust standards from 8-hour shift exposure measurements. Therefore, if you take a sample over a period other than eight hours, you must adjust the concentration measurement to be equivalent to an eight-hour exposure. This will protect miners working shifts longer than eight hours, and would be accomplished by multiplying the sampler flow rate by 480 minutes, regardless of the length of time during which the sample was actually collected. (In these examples, to determine equivalent concentrations of respirable coal mine dust: MRE equivalent concentration (mg/m

EP07JY00.001

where: rate of sampling = 0.002 m

/min).

For example, suppose a DO sample is collected over a 9-hour shift that includes one hour of travel time. Suppose that the amount of dust accumulated during travel is negligible, and the amount of dust accumulated during production is 1.5 mg. If the concentration were not adjusted to an 8-hour equivalent, it would be diluted by the time spent traveling and calculated as 1.92 mg/m

. Under the proposed definition, the calculated concentration would be 2.16 mg/m

The proposed definition does not change the daily limit on accumulated exposure 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 exposure limit of 8 × 2.0 = 16 mg-hr/m

. The proposed definition of concentration would maintain this same MRE-equivalent 16 mg-hr/m

daily limit, regardless of the length of any shift worked.

To continue the example, the exposure accumulated during a day is the same, whether from 8 hours at an average of 2.16 mg/m

or from 9 hours at an average of 1.92 mg/m

. In either case, the MRE-equivalent exposure accumulated for the day is 17.3 mg-hr/m

, which exceeds the intended daily limit of 16 mg-hr/m

. Under the proposed definition, this would be reflected by the fact that the calculated concentration exceeds 2.0 mg/m

. MSHA solicits comments on this method of adjusting concentrations to an 8-hour equivalent.

Designated Area (DA)

The existing definition would be modified to permit the Secretary to identify designated areas and to remain consistent with existing procedures which have been in effect since 1980. Once identified, the location of these DAs and the respirable dust measures to be used at the dust generating sources for these locations must be contained in the operator's mine ventilation plan as provided for under § 75.371(t). However, the operator would not be required to sample these DA's under the proposal. MSHA is also proposing to transfer the requirement for identifying each DA specified in existing § 70.208(e), which will be removed, to revised § 70.2(e).

Mechanized Mining Unit (MMU)

The existing definition would be modified by removing § 70.207(e) (Bimonthly sampling; mechanized mining units) which will be deleted, and revising § 70.207; and by transferring the requirements for identifying each MMU specified in existing §§ 70.207(f)(1) and (f)(2), to revised § 70.2(o).

Quartz

The existing definition of quartz 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 procedure, thereby enabling other laboratories to reproduce quartz determinations made by MSHA.

The following new definitions are being proposed:

Critical Value

“Critical value” would mean the maximum acceptable full shift dust concentration measurement demonstrating that the applicable verification limit has been met at a high level of confidence. Appendix A explains how each critical value was derived. The specific critical values and their use are detailed in §§ 70.209 and 70.213.

Dust Control Parameters

“Dust control parameters” would mean the respirable dust control requirements of a mine ventilation plan, including engineering or environmental controls, maintenance procedures, and any other requirements described in a ventilation plan. These requirements are intended for the protection of miners from excessive levels of respirable dust and must be in place on every production shift. To assure compliance with the ventilation plan, you must check the dust control parameters on each MMU before beginning production, as required under § 75.362(a)(2). This term has not been formally defined until now.

Engineering or Environmental Controls

“Engineering or environmental controls” would mean all methods that control the level of respirable dust in the work environment by either reducing dust generation or by suppressing, diluting, capturing or diverting the dust being generated during the mining process. Throughout the proposal, the terms “engineering” and “environmental” controls are used interchangeably. The Racal® Airstream helmet (or the 3M

Airstream

Helmet-Mounted PAPR), or any other respiratory protective device approved and labeled as such by the National Institute for Occupational Safety and Health (NIOSH), is not defined as an engineering or environmental control.

Full Shift

“Full shift” is defined differently for purposes of plan verification and abatement sampling, and for bimonthly compliance determinations. For purposes of abatement and plan verification, “full shift” would mean an entire work shift, including travel time to and from the MMU. Because of the way MSHA intends to define “concentration,” this would be equally protective regardless of the production and travel times. For example, suppose miners at one MMU travel for one hour and mine for eight hours. Miners at another travel for two hours and also mine for eight hours. Suppose, further, that the dust concentration during travel is negligible and that the dust concentrations are identical during production at the two MMUs. Then the amount of dust accumulated on a filter will be the same, say 1.0 mg, in both cases. Applying the proposed definition, the dust concentration calculated for both MMUs would be 1.44 mg/m

For purposes of bimonthly compliance determination, MSHA would continue its current practice of limiting sampling to a 480-minute maximum. MSHA solicits comments on whether “full shift” for compliance sampling purposes should be defined in the same way as for abatement and plan verification purposes. MSHA also solicits comments on whether “full shift” should be defined, as proposed, in the same way for abatement and plan verification purposes.

Material Produced

“Material produced” would mean the total amount of coal and/or other substance extracted by an MMU during any production shift. In order to properly assess the effectiveness of the mine 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 MMU each shift under a new paragraph (h) of § 75.370.

MRE

“MRE” would mean Mining Research Establishment of the National Coal Board, London, England.

Powered Air-Purifying Respirators (PAPRs)

“Powered, air-purifying respirators (PAPR)” would mean a NIOSH approved loose-fitting respirator that uses a blower to force the ambient air through air-purifying elements to deliver filtered air to the miner's breathing area. Under the proposal, an operator who employs longwall mining has the option of using either powered, air-purifying respirators (PAPRs) or verifiable administrative controls as a supplemental means of control once MSHA has determined that concentrations of respirable dust have been reduced as low as is feasible with engineering and environmental controls. This may include RACAL® Airstream helmets or similar devices that are available now or in the future. The reason for excluding other types of approved respirators is discussed in section II.B.1.

Verifiable Administrative Control

“Verifiable administrative control” would mean a work practice intended to reduce the miner's full shift exposure to respirable dust hazards by altering the way in which work is performed. Examples include rotation of miners to areas having lower concentrations of respirable dust, rescheduling of tasks, and modifying work activities to reduce exposure. A “verifiable administrative control” must be (1) capable of review to confirm proper implementation; (2) clearly understood by miners; and (3) applied consistently over time.

Verification Limits

“Verification limits” would mean the maximum dust concentration for which the ventilation plan has been verified as effective in maintaining during the full shift. There are two separate verification limits: An MRE-equivalent concentration of 2.0 mg/m

for respirable coal mine dust and an MRE-equivalent concentration of 100 μg/m

for respirable quartz dust. Both of these

limits apply to dust concentrations measured over a full shift.

MSHA does not enforce a separate standard for quartz dust. It regulates exposures to quartz and coal mine dust by reducing the applicable standard for coal mine dust, by means of a formula, when quartz content of the respirable dust is above 5 percent. This formula (10 divided by the concentration of quartz, expressed as a percentage) establishes an applicable coal mine dust standard that, in effect, limits quartz concentrations in the mine environment to no more than 100 μg/m

. For example, when the quartz content is 5 percent, the applicable standard is 2.0 mg/m

; when the quartz content is 10 percent, the applicable standard is 1.0 mg/m

. Five percent of 2.0 mg/m

and 10 percent of 1.0 mg/m

are each 0.100 mg/m

or 100 μg/m

The Advisory Committee recognized that a significant quartz exposure hazard continues to exist in coal mines, especially for operations such as roof bolting. Based on MSHA data, 66 percent of underground coal mines are operating on a reduced dust standard due to the respirable dust in the mine environment containing a high percentage of quartz. MSHA data also indicates that 73 percent of the over 600 roof bolters and over 29 percent of the MMUs sampled bimonthly by mine operators are operating under reduced dust standards. The number of reduced standards in effect indicates that a significant potential health risk due to quartz exposure continues to exist. Under the current program, miners can be exposed to excessive quartz levels while the dust standard-setting process takes place. For example, consider a recent situation where an MSHA dust sample of a roof bolter was 0.9 mg/m

; a level that was in compliance with the applicable standard, 1.3 mg/m

. However, when the sample was analyzed for quartz the results indicated that the actual concentration of quartz dust in the mine environment exceeded 270 μg/m

; or more than two and a half times above the permissible level of 100 μg/m

. The only action that could be taken in this particular situation was to initiate the dust standard-setting process, which, on average, can take at least one month or longer. The existing standard-setting process continues from the time the operator is cited for violating the reduced standard through the time MSHA enforces final corrective action.

Under this proposal, MSHA would require operators to anticipate the potential for quartz exposure and to incorporate controls prior to approval of the mine ventilation plan. In order to verify that the operator has incorporated such controls, 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 percent quartz in the dust during the verification process.

This process would require operators to address both the potential for respirable coal mine dust and quartz dust exposure. As recommended by the Advisory Committee, the proposed plan verification process would establish a monitoring and compliance framework to aid MSHA and the coal mine operator in targeting mining situations where quartz exposure constitutes a significant hazard and enhanced dust control procedures are required.

Verification Production Level (VPL)

The “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 an MMU. (§ 70.208 explains how to establish the VPL if you do not have records for 30 production shifts.)

We believe that the 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 this VPL would provide assurance that excessive dust concentrations would be avoided on a majority of production shifts. MSHA believes that using this VPL is more protective of miners' health than the current practice of evaluating plan adequacy based on MSHA inspector samples taken when production can be as low as 60 percent of the average production. We note however, that a VPL defined as a higher production percentile than is being proposed would likely assure that miners would be more protected on a majority of production shifts. The Agency welcomes comments on both the use of a VPL and the appropriate production percentile to use to define it.

Since approximately 50 percent of all production shifts are expected to exceed average production, it follows that the vast majority of all production shifts exceed 60 percent of average production. Therefore, by using 60 percent of average production as the lower range of the production criteria for plan evaluation purposes, as required under current inspection procedures, we have no assurance that the plan would be effective under the vast majority of production conditions.

If you do not have records for 30 production shifts, you can use the minimum production actually achieved on a shift used to verify the plan's effectiveness as your VPL.

Verification Sample

“Verification sample” would mean a sample collected for purposes of plan verification. In order to be valid the sample must be collected on a full shift during which the amount of material produced is at or above the VPL. Only those engineering or environmental controls and other measures listed in the mine ventilation plan may be employed, at levels not exceeding 115% of the quantities specified in the plan during the shift in which the sample is collected. For example, if the plan specifies an air quantity of 4,000 cfm, the quantity measured during verification must not exceed 4,600 cfm (4,000 cfm x 1.15 = 4,600).

Section 70.100 What are the respirable dust standards when quartz is not present?

MSHA is proposing no substantive changes to existing § 70.100(a) and (b), except for removing the reference to § 70.206 (Approved sampling devices; equivalent concentrations) from existing paragraphs (a) and (b) and replacing it with revised § 70.2(c). The requirements of revised § 70.2(c) are similar to the previous standard in § 70.206. The proposal retains the respirable dust standard of 2.0 mg/m

in existing paragraph (a) and the intake air standard for respirable dust of 1.0 mg/m

in existing paragraph (b).

Section 70.101 What is the 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 respirable dust standard below 2.0 mg/m

when the quartz content of the respirable dust in the mine atmosphere is above 5 percent. However, the Agency is proposing to change how it arrives at an average quartz percentage that is used to establish an applicable dust standard.

MSHA recently published a proposed “Program Policy Letter (PPL) on Samples Used to Determine the Respirable Dust Level When Quartz is Present” for public comment [64 FR 65671, November 23, 1999] whereby the standard would be determined based solely on the results of multiple MSHA samples. Under this proposal, as in the PPL, MSHA would no longer be using a combination of MSHA and mine operator sampling for determining the average quartz percentage, which has been the practice since 1985. Instead, as discussed in section III.B, this proposal

would establish MSHA sampling as the exclusive basis for determining the reduced standard and require three valid MSHA samples to set a reduced standard. Since we are sampling underground mines bimonthly, we will have no difficulty in collecting the required number of samples to arrive at the average quartz percentage. We believe our samples will be more representative of the level of quartz to which miners are exposed than as determined currently. This increased level of sampling should also allay any operator concerns regarding the collection of “misleadingly high” samples during atypical periods. We would also begin reporting quartz levels to the nearest tenth of a percent. This is intended to be more protective for the miner than under the current program of truncating results to the nearest full percent. We believe that the method for establishing reduced standards will be more protective for the miners than the current program.

Verification of Ventilation Plan Effectiveness.

Existing § 75.370 requires you to develop an underground coal mine ventilation plan that is designed to control methane and respirable dust in the mine. It further requires that the plan be suitable to the conditions and mining systems at the mine. Proposed §§ 70.201 to 70.211 sets forth the steps that MSHA will follow to demonstrate that your mine ventilation plan required by § 75.370 is effective in controlling respirable dust under typical mining conditions. This demonstration would be required before MSHA approves the mine ventilation plan.

Under §§ 70.201 to 70.211, MSHA would verify the effectiveness, for the control of respirable dust, of all mine ventilation plans submitted to the District Manager for approval under § 75.370. To do this, MSHA would collect full shift samples, called “verification samples.” For MSHA to approve the plan, these samples would have to demonstrate that the plan's dust control parameters are effective in maintaining concentrations of respirable coal mine dust and quartz dust in the working environment of MMUs at or below 2.0 mg/m

and 100 μg/m

, respectively, under typical mining conditions.

MSHA has drafted the regulatory text of this proposal in a question and answer format. The remainder of the Section-by-Section discussion also follows this format. As discussed in Chapter IV paragraph A below, we request your comments on this format.

Section 70.201 Who must have a verified ventilation plan?

Section 75.370 requires all underground coal mine operators to submit a mine ventilation plan for approval. The proposed § 70.201 would require the verification of these plans in terms of their effectiveness in controlling dust.

Section 70.202 What is a verified ventilation plan?

A ventilation plan submitted under § 75.370 must be designed to control respirable dust and must be suitable to the conditions and mining systems at the mine. In order for the plan to be verified under this proposal, the plan's dust control parameters must be demonstrated to be effective, at a high level of confidence, in maintaining the concentration of respirable coal mine dust and quartz dust in each MMU at or below 2.0 mg/m

and 100 μg/m

, respectively. This demonstration would be based on MSHA full shift verification samples, which are collected when the amount of material produced is at or above the VPL and only the engineering or environmental controls and other measures included in the ventilation plan are in place, at levels not exceeding 115% of the quantities specified in the plan.

Section 70.203 What will trigger the plan verification process?

There are several ways in which the plan verification process could be initiated. You would trigger the process by submitting a new ventilation plan under § 75.370, or amending a previously approved ventilation plan under § 75.371(f). The verification process could also be triggered if the District Manager requires you to change your plan after determining that your dust control parameters are no longer effective. Finally the verification process could be triggered if you propose revisions to a previously verified ventilation plan and the District Manager determines that the proposed revisions may cause the plan to be inadequate.

Once your ventilation plan has been verified as effective, it should not be necessary to reverify your plan every six months. However, you may be required to change your plan parameters based on (1) results of the MSHA six-month review of the ventilation plan as required by § 75.370(g), (2) excessive dust concentrations measured by MSHA sampling, 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 plan. For example, if you are cited by MSHA for exceeding the applicable dust standard the District Manager may have cause to question the adequacy of the previously-approved plan.

Also, depending on sampling results and production records, if your production exceeds the VPL during MSHA sampling, the District Manager may require you to verify the ventilation plan at the higher production level. For example, suppose your VPL is 10,000 tons and all five MSHA concentration measurements exceed the applicable standard on a shift for which the production is 12,000 tons. Then, if your production records indicate that you have exceeded the VPL on more than 33 percent of all production shifts during the previous six months, MSHA would initiate the verification process.

Section 70.204 When will MSHA conduct verification sampling?

The District Manager will notify you of the schedule for verification sampling after granting provisional approval of your ventilation plan. However, before you receive provisional approval, you may be required to change your plan if the District Manager determines that your dust control parameters are inadequate or unsuitable for the current mining conditions. If provisional approval is not granted, you may not operate the affected MMUs. Since more than 700 existing mine ventilation plans may require verification, MSHA will not be able to verify all plans immediately. Under proposed § 70.204 the District Manager would notify you of the date when MSHA intends to collect verification samples.

Section 70.205 What must I (the operator) do to comply this standard?

When the District Manager notifies you that your mine has been scheduled for verification sampling, you would need to make sure that all the dust control parameters specified in your ventilation plan are fully implemented. Since the objective of plan verification is to determine the effectiveness of the plan's dust control parameters in controlling respirable dust under typical mining conditions, paragraph (a) would require you to utilize only the dust control parameters listed in the ventilation plan that was provisionally approved by the District Manager. On the date scheduled for verification sampling, you should establish production levels at or above the VPL specified in the plan, using only the dust control parameters and other measures listed in the plan.

Recognizing that engineering or environmental controls such as air quantity and velocity 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 levels specified in the plan. If, on the date of verification sampling, a measured quantity exceeds the corresponding quantity specified in the plan by more than 15 percent, you will have the option to either (1) adjust the parameter(s) to what is specified in the plan before verification sampling begins or (2) make no adjustment to the parameter(s) prior to verification sampling. Under the second option, plan approval will be contingent on incorporating into your plan the maximum values of parameters in effect during verification sampling. If verification samples were taken when a parameter measurement exceeded 115 percent of the level specified in the plan, then (assuming none of the verification samples exceeded the critical values) that parameter quantity, as measured, would be incorporated in the plan ultimately approved by the District Manager.

As of the effective date of the final rule, you would be required to begin maintaining records of the amount of material produced by each MMU during each shift. This would enable you to establish the “verification production level” (VPL)—the minimum production level at which you must demonstrate the plan's effectiveness.

Before you submit a previously approved ventilation plan to the District Manager for review and approval, proposed paragraph (c) would require you to provide additional information. This additional information is described under § 75.371(f) of this proposal.

To enable us to maximize our inspection resources and to promote an orderly verification process, proposed paragraph (d) would require you to notify the District Manager in a timely manner if you are unable to meet the conditions for verification sampling on the scheduled date. Failure to provide notification may be cause for revocation of the provisional approval of your ventilation plan.

In accordance with section 103(f) of the Mine Act and the recommendations of the Advisory Committee, miners and their representatives would be provided the same walkaround rights during plan verification sampling as they are provided during any other physical inspection made pursuant to the provisions of section 103(a) by an authorized representative of MSHA.

MSHA believes that under the guidance of the Interpretive Bulletin (43 FR 17546, April 25, 1978) these 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.

The process of plan verification sampling is necessary to obtain information related to approval of the mine's ventilation plan and whether coal mine dust will be adequately controlled to protect miners health. Consequently, miners and their representative would have the right to accompany the inspector with no loss of pay for the time during which the representative exercises this right. However, this right is limited by Section 103(f) to only one such representative of miners.

Section 70.206 Who will MSHA sample and where will MSHA place the sampling device(s) when conducting verification sampling?

MSHA will sample specific occupations within an MMU to demonstrate your plan's adequacy. These occupations would be selected because, based on past experience, within an MMU they would likely be exposed to the highest respirable coal mine dust concentration and, therefore, would be at greatest risk of overexposure. Therefore, MSHA would sample the environment of the DO (as under existing § 70.207), the roof bolter operator(s) (occupation codes—012, 014 or 046), the longwall jack setters (occupation code—041), and any other occupation that the District Manager may designate for sampling after reviewing your ventilation plan.

Section 70.207 How many shifts will MSHA sample to verify my ventilation plan?

This proposed section would explain that the number of shifts required to verify your ventilation plan would depend on two factors: first, the actual operating conditions during the shift that is sampled; and, second, the sample results. To qualify as a verification sample, 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 you are able to achieve these operating conditions. We may need to sample several production shifts before the production level on any single shift qualifies for verification purposes. We may verify the plan based on this single shift—but only if all concentration measurements on the sampled shift are at or below the appropriate critical values proposed in § 70.209. This would demonstrate the plan's effectiveness at a high level of confidence. If any of the measurements exceed the appropriate critical value, then we would collect verification samples taken on one to three additional shifts, depending on the concentrations measured on those shifts. Since these additional shifts must also meet the criteria for production, and use only the engineering or environmental controls and other measures specified in the ventilation plan, we may have to sample a total of more than four shifts.

Assuming that you make 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 you made no special production effort, there would be a 13-percent chance we would need to sample more than five shifts and a 1.7-percent chance we would have to sample more than 10 shifts.

On the other hand, again assuming no special production effort, there would be a 98-percent chance we would need 10 or fewer shifts and a 70-percent chance that we would need three or fewer shifts.

This assumes that the dust concentration measurement for each shift does not exceed the critical value corresponding to the number of shifts sampled. If you make a special effort to achieve high pr

This text is long and has been trimmed here. Open the source document for the complete record.

This is a copy of a public record, reproduced as it was published. It is not legal advice, and it may not be the version a court would rely on. Check the official source before you cite it.