Mine Safety and Health Administration (MSHA), Labor.
Proposed rule; notice of hearings.
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
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.
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
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
Carol J. Jones, Director, Office of Standards, Regulations, and Variances, MSHA; 703–235–1910.
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:
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
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
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,
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
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
In response to concerns about the Federal coal mine dust program (MSHA, 1992), MSHA's
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),
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.
On January 31, 1995, the Secretary of Labor established the
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
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.
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.
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.
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.
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
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.
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
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
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.
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 (
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.
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
• 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 (
• The miners' representative will have walkaround rights during sampling, thereby increasing miners' confidence in the dust sampling program.
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
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.
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 (
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.
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
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].
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
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
For example, suppose that the MMU is on a 1.3-mg/m
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.
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 (
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
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.
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.
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.
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
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.
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.
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)
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
As discussed earlier, MSHA is proposing to revoke operators' sampling program in underground mines and assume full responsibility for all compliance sampling.
(b)
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.
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.
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 the VPL would provide assurance that excessive dust concentrations will be avoided, even on shifts with higher-than-average production. This is more protective of miners 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.
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
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.
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.
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 (
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,
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
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) (
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
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,
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
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
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
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,
Laboratory and in-mine studies (EPF studies) show that mine ventilation air flow or velocity, the primary means
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,
More recent studies conducted by Bhaskar,
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
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.
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
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
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
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.
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
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.
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.
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.
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:
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
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
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
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
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).
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).
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” 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” 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” 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
“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” 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” would mean Mining Research Establishment of the National Coal Board, London, England.
“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” 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” 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
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
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
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.
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” 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).
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
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
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
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
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 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.
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
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.
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.
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.
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.
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.
If you are starting a new MMU or mine, you may not have 30 shifts of production data available when you submit a new ventilation plan. In such cases, proposed § 70.208 requires you to establish the VPL as the minimum production level actually achieved on a shift used to verify the plan's effectiveness. For example, assume we initiate verification sampling of your longwall MMU. Based on the dust
This is a new section that proposes “critical values” that the District Manager would use to determine whether your plan's dust control provisions should be approved. These critical values, which differ according to the number of shifts used for verification, are listed in Table IV–1. When verification sample results do not exceed the appropriate critical value for respirable coal mine dust or quartz dust, we can be confident that the engineering or environmental controls in place during verification sampling successfully prevented excessive dust concentrations at the sampled locations. Therefore, MSHA would approve your plan when the dust control parameters are in place during verification sampling and none of the measurements obtained from your verification samples exceeded the appropriate critical value. Appendix A explains how the critical values were derived.
The proposed approval process would allow the District Manager to base verification sampling on a reasonably small number of shifts, while maintaining a high level of confidence that approved ventilation plans adequately prevent excessive dust concentrations. We would have to sample at least one full shift under the operating conditions specified in the mine ventilation plan before we could make any determination of the plan's adequacy. The plan would be approved if all samples on that shift meet the criteria for a verification sample as defined in § 70.2, and none of the sample results exceed the appropriate critical value for a single shift listed in Table IV–1. However, if any verification sample resulted in a coal mine dust measurement greater than 1.71 mg/m
The following two examples illustrate how we would determine if your plan's dust control provisions should be approved:
Suppose samples were taken on two shifts. We would approve the dust control provisions of your plan if all quartz and coal mine dust measurements obtained on the two shifts were less than 1.85 mg/m
Suppose verification samples were taken on four or more shifts. We would approve the dust control provisions as proposed if no measurement exceeded 2.0 mg/m
This is a new section that would require you to take certain actions whenever a verification sample results in a measurement exceeding the verification limit for either respirable coal mine dust (2.0 mg/m
When you receive notice from MSHA that you have exceeded either verification limit, you must immediately take corrective action. You must lower excessive respirable dust concentrations, so that none of your full shift measurements exceed verification limits in any of the identified occupational environments or sampling locations. At the same time, you must make approved respiratory equipment available to affected miners in accordance with § 70.300.
You would also be required to document the corrective actions taken for the District Manager, within five days of MSHA's notification that you have exceeded a verification limit. This documentation must describe all of your corrective actions, including proposed changes in dust control parameters. You would be encouraged to seek technical assistance from the District Manager to help you determine what additional corrective measures would be reasonably likely to reduce excessive dust concentrations.
The District Manager will notify you if your ventilation plan is provisionally approved and when MSHA will again commence verification sampling. The District Manager may require you to make additional changes in your plan parameter(s) based on the results of verification sampling before starting sampling over again. If no changes are required, MSHA will continue
The District Manager would choose, on a case-by-case basis, between resuming verification sampling or starting plan verification anew. MSHA would not necessarily require a revision of the ventilation plan nor start the ventilation verification process over again because a verification sample exceeded the verification limit by a small amount, such as 0.05 mg/m
MSHA would not issue citations for exceeding verification limits during the plan verification process. However, MSHA will issue citations under proposed § 70.210(a) for failure to take action required to address the cause of the excessive dust levels once you have been notified by MSHA.
This proposed section would continue to require you to use all feasible engineering or environmental controls before implementing any supplemental means of control at longwall mining operations. For continuous and conventional mining operations MSHA would suggest additional engineering and environmental controls. Even if these controls do not prevent full shift respirable dust concentrations from exceeding the verification limits, you must continue to use them to reduce respirable dust to the lowest feasible level. Engineering or environmental controls have been the primary form of dust control for the past 30 years. The Advisory Committee recommended that engineering or environmental controls remain the primary means of protecting coal miners. Consistent with the Mine Act and the Advisory Committee's recommendation, under this proposal engineering or environmental controls continue to be recognized the primary means to control exposure to respirable dust.
If you operate an MMU employing either a continuous or conventional mining method, we believe feasible engineering or environmental controls are available to control respirable dust to an acceptable level. Controls include better design of water spray systems for dust suppression and air movement, use of dust collectors, and improved face ventilation systems.
Of approximately 800 continuous miner MMUs operating in over 500 underground mines, over 90 percent employ extended cut techniques and are being operated remotely (Elam, August 1999). As a result, the continuous miner operator, the occupation normally identified as the DO for bimonthly sampling purposes, is no longer required to work close to the face area where material is being extracted.
Roof bolting machines, a major generator of respirable quartz dust on continuous miner MMUs, must be equipped with suitable drill dust controls. Under § 72.630, drill dust must be controlled by permissible dust collectors, by water, water with a wetting agent, by ventilation, or by any other method approved by MSHA.
These and other approaches, as well as results of laboratory and field studies of the effectiveness of various dust controls, can be found in several detailed compilations prepared by the former U.S. Bureau of Mines, whose responsibilities have now been transferred to NIOSH. (U.S. Bureau of Mines various reports, undated). If you exceed either verification limit, the District Manager will suggest that you implement additional controls.
As discussed in section II. B., MSHA recognizes that improvements in control technology have not kept pace with the increase in production technology associated with high-production longwall MMUs. Average longwall shift production reported during bimonthly sampling has increased from 890 tons per shift in 1980, to over 4900 tons per shift in 1999. Given the state of longwall dust control technology, the currently-available engineering or environmental controls may not succeed in sustaining continuous compliance at certain locations downwind of the longwall operator (occupation code—044) at some high-production longwall MMUs under typical mining conditions.
For your longwall operation, if you believe that you have implemented all feasible engineering or environmental controls, you may submit a written request to MSHA's Administrator for Coal Mine Safety and Health in Arlington, Virginia, to request for MSHA to review your longwall mining operation and determine if you have, in fact, implemented all feasible engineering controls.
Upon receipt of such a request, MSHA would solicit guidance from a panel of experts which would be established for making such determinations. Members of this panel would have extensive knowledge in respirable dust control and would represent the following organizations within MSHA: Technical Support, Division of Health, the MSHA District having jurisdiction over your mine, and one other MSHA District. In some cases, we may solicit advice from NIOSH. As part of their deliberations, the expert panel may visit your mine to observe the various controls in operation. Any decisions reached by this panel would be based on the review of available information, their combined experience in dust control, and sound engineering judgement.
If the Administrator determines that you are using all feasible engineering or environmental controls, we would notify you in writing that you have been granted approval to use either PAPRs approved under 42 CFR 84 or verifiable administrative controls as a supplemental means of control to protect miners required to work downwind of the longwall operator. You would also be informed that the location of the DO would be changed from the 060 to the 044 occupation, or other occupation designated by the District Manager depending on how your longwall MMU is ventilated. You must continue to maintain the work environment of the new DO at or below the verification limits using engineering or environmental controls, as demonstrated during plan verification. As discussed earlier, while it may be difficult to make the environment safe for some miners working on the longwall face under certain mining conditions, MSHA believes that an acceptable work environment can be provided for the longwall operator (occupation code—044) and other miners on a continuing basis. You must choose either PAPRs or verifiable administrative controls for your ventilation plan. The notification would grant approval of an interim verification plan allowing the use of PAPRs or administrative controls as a
These sections would establish the requirements for utilizing PAPRs to supplement engineering or environmental controls.
This proposed section would require you to submit a revised ventilation plan to MSHA within five days of receipt of MSHA's written approval in accordance with § 70.211 if you choose to use approved PAPRs to supplement engineering or environmental controls. Your revised plan must specify the engineering or environmental controls you believe are capable of maintaining respirable dust concentrations (1) at or below the verification limits in the environment of the new DO (previously occupation 060, and currently occupation 044 or another occupation designated by the District Manager), and (2) at or below two times the verification limits in the environment of any miner working on the longwall face (downwind of the DO) who is required to wear a PAPR.
This is based upon the demonstrated effectiveness of PAPRs on longwall MMUs and the range of longwall air velocities observed by MSHA inspectors discussed earlier in section II.B.2, which led MSHA to reduce the protection factor assigned to loose fitting, helmeted PAPRs from 25 to two. In other words, the maximum full shift, MRE-equivalent concentration of respirable dust allowed in the environment of any miner working on the longwall face (downwind of the DO) who is required to wear a PAPR cannot exceed 4.0 mg/m
In addition to specifying all feasible engineering or environmental controls to be used, you would be required to include in your plan a written respiratory protection program for PAPRs for all affected miners as described in § 72.710. MSHA's District Manager may require you to modify the respiratory protection program before granting provisional approval of your ventilation plan.
Once MSHA grants provisional approval, we will verify the effectiveness of the revised dust control provisions of the ventilation plan. We will sample the environment of the DO and of those miners that your plan requires to wear approved PAPRs. If effectiveness of the plan is verified, it would become your interim ventilation plan.
In order to continue using PAPRs for compliance purposes, you would be required to maintain the effectiveness of your engineering or environmental controls, as well as the effectiveness of your approved PAPR respiratory protection program. We believe that the effectiveness of a PAPR is dependent upon proper training and continued maintenance. Training and maintenance procedures are part of an effective respiratory protection program. The provision 30 CFR 72.710 requires all respirators used in an underground coal mine to be selected, fitted, used, and maintained in accordance with the provisions of the American National Standards Institutes “Practices for Respirator Protection ANSI Z88.2–1969.” These provisions include training miners in the use and maintenance of respirators and the limitations of the specific respirator worn. Necessary maintenance includes examining it for defects prior to use, charging the batteries properly, and appropriate replacement of parts including, but not limited to, the filter elements, visors, batteries, blowers, and face seals. Furthermore, all respiratory equipment used in an underground coal mine must be approved by the National Institutes for Occupational Safety and Health (NIOSH) under 42 CFR part 84.
The use of PAPRs is not intended to be permanent. Their use as a supplemental control would be permitted only on an interim basis, until feasible engineering or environmental controls become available. You would have to implement any feasible engineering and environmental controls, as they become available.
Approval of your interim mine ventilation plan would depend on the results of verification sampling and the operating conditions in effect for each sample. Paragraph (b) adds additional criteria or “critical values” for coal mine dust and quartz dust to those specified in § 70.209. These additional critical values, listed in Table IV–2, would apply to the environments of workers required to wear PAPRs under the plan. The critical values given in § 70.209 would continue to apply to DO samples. However, once an interim ventilation plan is approved, the position of the DO will change. Your plan would be approved if it reflects the dust control parameters in place during verification sampling and none of the verification samples exceed the corresponding critical values. No DO dust sample obtained during the verification process can exceed 2.0 mg/m
In order to continue use of PAPRs to supplement your engineering or environmental controls, you must comply at all times with the dust control provisions of your interim mine ventilation plan. This includes: (1) implementing and maintaining all feasible engineering or environmental controls on each shift; and (2) complying with all provisions of your approved PAPR respiratory protection program. In addition, to ensure the continued effectiveness of your approved dust control parameters, no DO sample taken by an MSHA inspector could exceed the applicable dust standard. Furthermore, no MSHA measurement for any miner working downwind of the DO could exceed twice the applicable dust standard.
Finally, you would be required to continue to seek improvements and implement, when they became available, any feasible engineering or environmental controls. MSHA will follow-up on your efforts in this regard as part of its regular six-month review of your mine ventilation plan under § 75.370.
Respirator programs require continuous administrative attention to assure continued effectiveness. MSHA's District Manager would evaluate, at least quarterly, the effectiveness of all installed engineering or environmental controls, the effectiveness of your PAPR respiratory protection program, and your performance in complying with all other plan provisions.
This proposed section would require you to review your dust control procedures and promptly take action which would prevent similar occurrences in the future. Also, you must review your approved PAPR respirator program to assure its continued effectiveness. Dust levels in excess of the applicable standard could result from a change in operating conditions, because of an abnormal condition or work practice, or due to production exceeding the VPL. If you determine that you cannot comply with the dust standard, you would need to amend your interim ventilation plan and submit it to the District Manager for review and approval.
If you are cited under § 75.371 for failure to comply with your approved interim plan, the District Manager may conduct an investigation to determine if you are complying with the dust control provisions of your approved interim ventilation plan. If the investigation discloses that you are not following your plan, MSHA may revoke approval of your plan.
Finally, the District Manager may revoke your interim plan and withdraw permission to use PAPRs for compliance purposes if you have a record of noncompliance with your interim ventilation plan, or if MSHA samples indicate that miners are not adequately protected. If this occurs, your revised interim plan must include a VPL at which you can comply with the applicable standard.
These sections establish requirements for using verifiable administrative controls to supplement engineering or environmental controls.
“Verifiable administrative controls” are work practices that reduce miners' daily exposure to respirable dust by altering the way in which work is performed such as rotating miners to areas having lower concentrations of respirable dust. To be considered verifiable administrative controls, it is necessary that the practices: (1) Can be reviewed to confirm proper implementation, (2) are clearly understood by miners, and (3) can be applied consistently over time. If you choose to use verifiable administrative controls for compliance purposes, paragraph (a) requires you to submit a revised ventilation plan to MSHA's District Manager within five days of receiving MSHA's written approval in accordance with § 70.211. This plan must specify: (1) the feasible engineering or environmental controls to be used for reducing respirable dust concentrations to the lowest possible level; (2) the verifiable administrative controls to be implemented on the longwall MMU; and (3) the procedures to be employed for ensuring compliance with the verifiable administrative controls on every shift.
Once MSHA grants provisional approval, we will verify the effectiveness of the revised dust control provisions of the ventilation plan. We will sample
The use of verifiable administrative controls is not intended to be permanent. Their use for compliance purposes would be permitted only on an interim basis, until feasible engineering or environmental controls become available. You would have to implement any feasible engineering and environmental controls, as they become available. You must make sure that you continue to comply with your approved administrative controls, and you must maintain the effectiveness of your engineering or environmental controls. Finally, you must implement any feasible engineering or environmental controls methods that become available, and that would prevent full shift dust concentrations from exceeding the applicable dust standard at any location at which miners normally work at the longwall face.
Approval of the dust control provisions of your interim ventilation plan depends on the results of your verification samples and on the actual operating conditions under which each sample was taken. None of the samples obtained during the verification process may exceed 2.0 mg/m
Under this section, you must immediately review your dust control procedures, including the effectiveness of your administrative controls, and take action to prevent similar occurrences in the future if any MSHA compliance sample exceeds the applicable dust
If you are cited under § 75.371 for failure to comply with your approved plan, the District Manager may conduct an investigation to determine if you are complying with the dust control provisions of your approved interim ventilation plan. If the investigation discloses that you are not following your plan, approval of your plan may be revoked.
Finally, the District Manager may revoke your interim plan and withdraw permission to use administrative controls for compliance purposes if you have a record of noncompliance with your interim ventilation plan, or if MSHA samples indicate that miners are not adequately protected. If this occurs, your revised interim plan must include a VPL at which you can comply with the applicable standard.
If you are cited for violating § 70.100 or § 70.101, you would be required to promptly review your dust control practices to determine the cause of the excessive dust concentration. You would also be required to take corrective action to prevent miners from being overexposed in the future by lowering the concentration of respirable dust to comply with the applicable dust standard. You would be required to take these actions within the abatement period fixed in a citation.
After reviewing your dust control practices and taking corrective action, you would be required to incorporate changes reflecting these actions into your ventilation plan in accordance with § 75.370(a)(2). If, in your opinion, the corrective actions taken do not warrant a change in your plan's dust control parameters, you would need to explain that in your response to the District Manager. This will enable the District Manager to determine if the ventilation plan should be changed and re-verified.
Based on the dust parameters that were in use for the results of the compliance sample(s) dust concentrations measured by MSHA samples, and the information submitted by the operator regarding the type(s) of corrective action that were taken, MSHA may elect to sample the cited entity to determine the effectiveness of your abatement actions. If these samples indicate compliance with the applicable dust standard, you would be required to incorporate your corrective actions in your mine ventilation plan. At a minimum you would be required to incorporate in your plan the actual parameters that were in effect when MSHA sampled. If the MSHA samples indicate continued noncompliance, then MSHA may revoke approval of your ventilation plan.
This proposed section would provide ready access to current information relating to the plan verification process and to the respirable dust conditions in the mine. You would be required to post on the mine bulletin board the actual values of specific dust control parameters measured by MSHA on shifts used for plan verification and all sample results. For the same reason, the proposal would require that all written notifications received from the District Manager regarding any aspect of the plan verification process. You could remove the information from the mine bulletin board after the plan is approved by the District Manager.
Also, you would also be required to post the results of MSHA compliance sampling on the bulletin board. These results must be posted for at least 31 days. These posting requirements are intended to promote miner awareness of the conditions under which the mine ventilation plan has been shown to be effective in controlling dust levels in their work environment. The goal is consistent with the statutory intent that miners play a role in preventing unhealthy conditions and practices where they work.
In order to conduct verification and compliance sampling, it is essential that you provide current information to us concerning the production status of MMUs and DAs within those mines that are in producing status. Therefore, to reduce the chances of visiting a mine whose operating status prevents the MSHA inspector from sampling, you would continue to be required to report the change in operational status of the mine, MMU, or DA to the MSHA District Office or to any other MSHA office designated by the District Manager. You would also be required to report a change in operational status if it would affect the verification sampling requirements under this proposal. Status changes would be reported in writing within three working days after the status change occurred. The reporting of changes in operational status is not a new requirement and is contained in existing § 70.220. MSHA is renumbering existing § 70.220 as § 70.221.
This proposal would amend § 75.370 by adding a new paragraph (h). Paragraph (h) would require that records of the amount of material produced each production shift by each MMU during the previous six-month period be made available for inspection by authorized representatives of the Secretary and the miners' representative.
These records are essential for the plan verification process. The records are needed to establish the verification production level (VPL) required under proposed § 75.371(f) and to confirm that the 30-shift period on which the VPL is based represents typical production conditions for the MMU. Additionally, MSHA and the miners' representative need these records to monitor changes in production levels that may affect the plan's adequacy. Finally, because verification of a plan's effectiveness is conditioned on the VPL, these records are necessary to determine if the VPL used in approving a plan continues to reflect typical production levels at the mine.
The production records for each MMU may be maintained in any form utilized by the operator to measure the total amount of material produced, so long as the method is the same as that used to establish the VPL required for plan verification. For example: number of loaded shuttle cars, feet of advance, raw tonnage, or number of longwall passes would each be an acceptable method of recording production—so long as the same method was consistently used.
The proposal would revise paragraphs (f) and (t). Existing paragraph (f) would be revised to require the ventilation plan to include any specific work practices used to minimize the dust
Also, every ventilation plan would be required to include information on the length of each normal production shift and to specify the VPL as defined in § 70.2. Although a VPL would be included in the ventilation plan, MSHA 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 33 percent of the production shifts over a six-month period, then this may trigger the plan verification process using a higher VPL.
For interim plans involving the use of powered, air purifying respirators (PAPRs) or verifiable administrative controls, the plan must also include the information respectively required under § 70.212(b) or § 70.216(a). This additional information is necessary to fully assess the adequacy of mine ventilation plans.
Since MSHA is proposing to revoke existing §§ 70.207 and 70.208 which require sampling by mine operators, existing paragraph (t) would be revised to remove the provision that mine operators identify in the mine ventilation plan the locations where samples for designated areas (DA) will be collected, including the specific location of each sampling requirement, and the reference to § 70.208. However, to ensure that the mine atmosphere where miners are normally required to work or travel is continuously maintained in compliance, proposed paragraph (t) would continue to require mine operators to identify in the mine ventilation plan the location of each DA, defined in proposed § 70.2(e), and the particular dust control measures that would be used at the dust generating sources for these locations. These locations would continue to be sampled by MSHA inspectors as discussed earlier (see Background Section) to determine compliance with the applicable standard and to assess the adequacy of the operator's dust control measures.
The proposed rule would revoke all operator sampling requirements associated with coal miners who have evidence of the development of pneumoconiosis under Part 90. MSHA is republishing the entire regulatory text of Part 90 as it would appear under the proposal for ease of review. Aside from a few technical clarifications which are described below, the only change to Part 90 would be to remove all references to operator sampling.
The scope of part 90 would not change under the proposal. However, the phrase “including respirable dust sampling for Part 90 miners” would be removed from the end of the sentence which states that “the rule also sets forth the operator's obligations.”
All definitions would remain unchanged under the proposal with the exception of those for “concentration” and “mechanized mining unit” which have been clarified as described below. The definition for “valid respirable dust sample” would be removed because mine operators would no longer collect Part 90 samples under the proposal. No discussion has been included below if the definition would not change under the proposal. For ease of reference, subsection references have been added for each definition.
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.
The existing coal mine dust standards were developed from 8-hour shift exposure measurements. Therefore, if a sample is taken over a period other than eight hours, the concentration measurement must be adjusted to be equivalent to an eight-hour exposure. This is necessary in order to provide equal protection to miners working shifts greater than eight hours and would be accomplished by multiplying the sampler flow rate by 480 minutes, regardless of the length of time that the sample was actually collected.
For this 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 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
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
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
The Part 90 respirable dust standard would not change. Since MSHA would collect all Part 90 samples under the proposal, the sentence which provides that “concentrations shall be measured with an approved sampling device and expressed in terms of an equivalent concentration determined in accordance with § 90.206” would be removed.
Because MSHA would collect all Part 90 samples, this section would be
An example has been added to explain how a reduced standard is established when respirable dust associated with a part 90 miner contains quartz in the amount of 20%.
This section would remain unchanged.
This section would remain unchanged.
This section would remain unchanged.
Under the proposal, mine operators would no longer collect respirable dust samples under Subpart C of Part 90. Consequently, all of Subpart C, “Sampling Procedures,” including §§ 90.201–209 would be removed. Existing § 90.210 would be renumbered as § 90.201. The requirements of this section would remain unchanged.
Under the proposal, mine operators would no longer collect respirable dust samples under Subpart C of Part 90. Consequently, all of Subpart C, “Sampling Procedures,” including §§ 90.201–209 would be removed. Existing § 90.220 would be renumbered as § 90.202. The requirements of this section would remain unchanged.
There would be no change in the filing requirements for respirable dust control plans under the proposal.
There would be no change in the approval process or notice requirements for respirable dust control plans under the proposal.
Since the 1800s, occupational respiratory disease associated with working in a coal mine has been commonly referred to as “Black Lung.” As coal is mined, respirable-sized dust is generated. Depending upon the mine location and its geologic features, silica may also be present in the mine atmosphere. Dust in air that is breathed by miners has the potential to be deposited in their lungs. Some of this dust may be retained. Coal mine dust remaining in the lungs of miners for prolonged periods of time has the potential to result in respiratory diseases, sometimes even after occupational exposure to respirable coal mine dust has stopped. There is a clear and direct relationship between miners' cumulative exposures (
Diseases resulting from long-term retention of coal mine dust in the lung include chronic coal workers' pneumoconiosis (simple CWP), progressive massive fibrosis (PMF), silicosis, and chronic obstructive pulmonary disease (COPD) (
Miners with simple CWP have a substantially increased risk of developing PMF. In the advanced stages of pneumoconiosis (
Factors that are important in the development of simple CWP, PMF and COPD include the type of dust (
In 1998, MSHA estimated that approximately 45,000 miners and 39,000 miners were employed at underground and surface coal mines, respectively (Mattos, 1999). A small percentage of the mining involved anthracite coal, the highest rank coal, while most involved bituminous coal which is a medium rank coal.
There are complementary data sources, described below, which provide estimates of the prevalence of occupational respiratory disease among coal miners. Together these data demonstrate the progress over the last thirty years in the reduction of occupational respiratory disease among coal miners, as well as the need for further action to reduce occupational lung disease among today's coal miners.
Estimates of the prevalence of simple CWP and PMF among the underground coal miners are gathered from the x-ray program, through which operators are required to provide miners the opportunity to be evaluated periodically for the presence of occupational lung disease, mandated pursuant to Section 203(a) of the Mine Act (30 U.S.C. 843(a)). However, miners are not required to participate. From 1970 to 1995, the prevalence of simple CWP and PMF among miners participating in the mandated x-ray program has dropped from 11 percent to 3 percent (MSHA, Internal Chart, 1998).
In accordance with 30 CFR part 50, those cases of occupational illnesses which both surface and underground coal mine operators learn of must be reported to MSHA. Under this requirement, mine operators reported 224 cases of pneumoconiosis (simple CWP and PMF, combined) in 1998 (Mattos, 1999). Of these, 138 cases occurred among coal miners who worked underground, while the remaining 86 cases occurred among surface coal miners (Mattos, 1999). There were also 14 cases of silicosis, eight in underground mines, reported to MSHA in 1998 in accordance with 30 CFR part 50 (Mattos, 1999). Since miners participate in both these programs at their own discretion, these data do not include the occupational health experience of all coal miners. The prevalence of occupational lung disease among participating miners may significantly differ from the prevalence among non-participants. Thus, the data from these programs may not be representative of the true magnitude of the prevalence of simple CWP and PMF among today's coal miners.
In the 1990s, MSHA conducted a series of one-time medical surveillance programs, in various regions of the country, to develop a more accurate estimate of the prevalence of simple CWP and PMF. Through these special programs, MSHA tried to minimize obstacles which may prevent some miners from either participating in or reporting to operators the results of respiratory diagnostic procedures. Nine
Also, as part of its ongoing effort to “end black lung now and forever,” beginning in October 1999, MSHA implemented a pilot program to provide miners at both surface and underground mines with confidential health screening. Referred to as the “Miners’ Choice Health Screening,” the program addresses the key recommendations of the Secretary's Advisory Committee by (1) increasing participation toward the 85-percent level and (2) expanding the scope of the eligibility to include surface coal miners and surface coal mine independent contractors. The pilot program operates separately from the existing Coal Workers' X-ray Surveillance Program administered by NIOSH. Since the Miners' Choice Health Screenings' inception, over 7,000 miners have been screened, with the participation rate in most areas exceeding 50 percent. With half of the x-rays taken during the first six months having been processed by NIOSH, preliminary results indicate a prevalence rate of approximately 2.25 percent.
The National Institute for Occupational Safety and Health (NIOSH) and the Mine Safety and Health Administration (MSHA) are concerned about the prevalence of occupational lung disease among today's miners. Epidemiological studies from the U.S. and abroad have consistently shown that underground and surface coal miners are at risk of developing simple CWP, PMF, silicosis, and chronic obstructive pulmonary disease (NIOSH Criteria Document, 1995).
Coal is a fossil fuel derived from partial degradation of vegetation. Through its combustion, energy is produced which makes coal a valuable global commodity. It has been estimated that over one-third of the world uses energy provided by coal (Manahan, 1994). Approximately 1,800 underground and surface coal mines are in operation in the United States annually producing slightly over a billion short tons of coal (Mattos, 1999).
Coal may be classified on the basis of its type, grade, and rank. The type of coal is based upon the plant material (
Aerosols are a suspension of solid or liquid particles in air (Mercer, 1973); they may be dusts which are solid particles suspended in the air. Coal dust may be freshly generated or may be re-suspended from surfaces on which it is deposited in mines. As discussed below, coal mine dust may be inhaled by miners, depending upon the particle size.
Coal mine dust is a heterogenous mixture, signifying that all coal particles do not have the same chemical composition. The particles are influenced by the type, grade, and rank of coal from which they were generated (Manahan, 1994). Irrespective of differences in coal characteristics, these dusts are water-insoluble, which is important biologically and physiologically. Unlike soluble dusts which may readily pass into the respiratory system and be cleared via the circulatory system, insoluble dusts may remain in the lungs for prolonged periods of time. Thus, a variety of cellular responses may result that could eventually lead to lung disease.
The principal route of occupational exposure to respirable coal mine dust occurs via inhalation. As a miner breathes, coal mine dust enters the nose and/or mouth and may pass into the mid airways (
Coal mine dust has a size distribution that is estimated to range between 1 and 100 micrometer (μm) (1 μm = 10
Particles that are above 10 μm are largely filtered in the nasal passages, although some of these particles may reach the thoracic (or tracheal-bronchial) region of the lung (
For the purposes of this rule, “respirable dust” is defined as dust collected with a sampling device approved by the Secretary of Labor and the Secretary of the Department of Health and Human Services (DHHS) in accordance with 30 CFR Part 74 (Coal Mine Dust Personal Sampler Units). In practice, the coal mine dust personal sampler unit has been used in the U.S. The particles collected with an approved sampler approximate that portion of the dust which may be deposited in the lung (West, 1990; 1992). It does not, however, indicate pulmonary retention (
It is also important to note that silica may be present in the coal seam, within dirt bands in the coal seam, and in rock above and below coal seams. Of the silica found in coal mines, quartz is the form which is found. Thus, quartz may become airborne during coal removal operations (Manahan, 1994). Miners may inhale dust that is a mixture of quartz and coal. MSHA is concerned with the inhalation of quartz since it may be deposited in the lungs of miners and produce silicosis. This is a restrictive lung disease which is characterized by a stiffening of the lungs (West, 1990; 1992). Silicosis has been seen in coal miners (
Consistently, epidemiological studies have demonstrated miners to be at risk of developing respiratory symptoms, a loss of lung function, and lung disease as a consequence of occupational exposure to respirable coal mine dust. As noted previously, risk factors include type(s) of dust, dust concentration, duration of exposure, age of the miner (often measured as age at time of medical examination), and coal rank.
a.
To determine if a miner has simple CWP or PMF, chest x-rays are taken and classified by a certified radiologist or reader. Opacities are identified on chest films and then classified using a scale of 0–3 (
Simple CWP can be associated with a loss of lung function and with premature mortality (Morgan,
Progressive massive fibrosis (PMF) is associated with decreased lung function and increased premature mortality (Rasmussen,
b.
The term, chronic obstructive pulmonary disease (COPD), refers to three disease processes that are often difficult to properly diagnose and differentiate: chronic bronchitis, emphysema, and asthma (Coggon and Taylor, 1998; Garshick,
Chronic Obstructive Pulmonary Disease (COPD) is characterized by airflow limitations, and thus there is a loss of pulmonary function. As in simple CWP or PMF, a miner with COPD may have a variety of respiratory symptoms (
Briefly, in chronic bronchitis and in asthma, there is excess mucous
The Mine Safety and Health Administration (MSHA) and the NIOSH recognize that respiratory symptoms, loss of lung function, and COPD may impair the ability of a miner to perform his job and may diminish his quality of life. Additionally, miners having such health effects are at increased risk of morbidity (
To better understand the human health effects of exposure to respirable coal mine dust and to more fully characterize the associated risks, it is important to consider data that have been obtained in animal based toxicological studies. To date, sub-acute studies (a study with a duration of 30 days, or less, in which multiple exposures of the same agent are given) and chronic studies (a study with a duration of more than 3-months, in which multiple exposures of same agent are given) attempted to mimic miners' exposures. Inhalation was generally the route of exposure, although several studies have also employed instillation techniques (
Most recent toxicological studies have been short-term studies, largely focusing on “lung overload” (Sipes, 1996; Oberdorster, 1995; Morrow, 1988, 1992; Witschi, 1990), species-dependent lung responses (Nikula,
The data from Moorman,
Epidemiology studies have consistently demonstrated the serious health effects of exposure to high levels of respirable coal mine dust (
Table V–1 lists epidemiology studies since 1986 whose results will be discussed on the basis of the type of observed health effect. Studies completed even earlier including the early work of Cochrane (1962), McLintock,
Both early and recent studies have shown that the lung is the major target organ (
a.
Attfield and Seixas (1995) have demonstrated a relationship between cumulative exposure to respirable coal mine dust and predicted prevalence of pneumoconiosis (
The recent paper of Kuempel,
The data of Attfield and Seixas (1995) and Kuempel,
Recently, Goodwin and Attfield (1998) reported that there were concerns regarding methodological inconsistencies across surveys given during the four rounds of the NSCWP. In particular, they noted the discordance in classification of simple CWP and PMF among readers of chest films. Despite potential discordance, Goodwin and Attfield (1998) have confirmed previous findings of a decline in simple CWP prevalence from 1969 to 1988. Yet, these analyses also demonstrated that simple CWP has not been eliminated. The Round 4 prevalence rates were 3.9 percent for simple CWP category 1 and higher, and 0.9 percent for category 2 and higher. This illustrates the need for continued efforts to reduce dust exposures.
Given the current system for monitoring exposures and identifying overexposures in the U.S., miners are at
The Attfield and Seixas epidemiological study (1995) is the most appropriate to use in estimating the benefit of reduction of overexposures. The authors applied scientific rigor to the collection, categorization, and analyses of the radiographic evidence for the group of 3,194 underground bituminous coal miners who participated in Round 4, 1985–1988, of the National Study of Coal Workers' Pneumoconiosis (NSCWP); this study population excludes 86 miners for whom there was missing exposure data or unreadable x-rays. Radiologic evidence was carefully collected and analyzed by multiple independent, NIOSH certified B readers to identify stages of simple CWP and PMF. In the targeted population of 5,557 miners, the participating miners (3,280) were similar to the non-participants (2,277) with regard to age at the first medical examination and prevalence of simple CWP category 1 or greater. The non-participants had worked slightly longer, yet had lower prevalence of simple CWP category 2 or greater, than the participants. This study describes the differences among current miners and ex-miners (health-related or job-related) in the relationships between the estimated cumulative exposure to respirable coal mine dust and prevalence of simple CWP category 1 or greater. Such data and relationships were not available in other U.S. studies and non-U.S. studies.
A potential limitation in the U.S. studies is the possible bias in the exposure data, which has been the subject of several studies (Boden and Gold, 1984; Seixas
The most complete exposure data available are those for coal miners in the United Kingdom (Hurley,
Bourgkard,
Love,
These investigators found a doubling in the relative risk of developing profusion of simple CWP category 0/1 for every 10 years of work in the dustiest jobs in surface mines. These respirable coal dust exposures were under 1 mg/m
Meijers,
Morfeld,
Starzynski,
Yi and Zhang (1996) conducted a study to measure the progression from simple CWP to PMF or death among a cohort of 2,738 miners with simple CWP who were employed at the Huai-Bei coal mine in China. Relative risks (
Hurley and Maclaren (1987) studied British coal miners who were examined between 1953 and 1978, over 5-year intervals. They have shown that exposure to respirable coal dust increases the risks of developing simple CWP and of progressing to PMF. As seen in their data analysis, these responses were dependent upon dust concentration and coal rank. That is, greater responses were seen at higher dust concentrations and with higher rank coal (
b.
Henneberger and Attfield (1997; 1996), Kuempel,
Attfield and Hodous (1992) studied U.S. miners who had spent 18 years underground (on average) and who participated in Round 1 (1969–1971) of the NSCWP. They observed that greater reductions in pulmonary function were associated with exposure to higher ranks of coal (
Seixas,
The U.S. findings on respiratory symptoms and loss of lung function in miners have agreed with those of previous British studies by Marine,
Soutar and Hurley (1986) examined the relationship between dust exposure and lung function in British coal miners and ex-miners. The men who were studied were employed in coal mines in the 1950s and were followed up and examined 22 years later. These miners and ex-miners were categorized as smokers, ex-smokers, or nonsmokers. The Forced Expiratory Volume in one second (FEV
Recent studies from China (Wang,
Wang,
As noted above, Bourgkard,
Carta,
Lewis,
There have been two recent mortality studies that have demonstrated a relationship between exposure to respirable coal mine dust and development of COPD. This association was reported by Kuempel,
Kuempel,
Meijers,
As mentioned previously, in addition to this proposed notice of rulemaking, today's
Having reviewed the reported health effects associated with exposure to coal mine dust, we have evaluated the evidence to determine whether the current regulatory strategy can be improved. The criteria for this evaluation is established by the Mine Act under section 101(a)(6)(A) [30 U.S.C. 811(a)(6)(A)] which provides that:
The Secretary, in promulgating mandatory standards dealing with toxic materials or harmful physical agents under this subsection, shall set standards which most adequately assure on the basis of the best available evidence that no miner will suffer material impairment of health or functional capacity even if such miner has regular exposure to the hazards dealt with by such standard for the period of his working life.
Based on Court interpretations of similar language under the Occupational Safety and Health Act, there are three questions that must be addressed: (1) Whether health effects associated with the current pattern of overexposures on individual shifts constitute a material impairment to miner health or functional capacity; (2) whether the current pattern of overexposures on individual shifts places miners at a significant risk of incurring any of these material impairments; and (3) whether the proposed rules would substantially reduce those risks.
The criteria for evaluating the health effects evidence do not require scientific certainty. The need to evaluate risk does not mean that an agency is placed into a “mathematical straightjacket.”
As explained earlier, MSHA's objective in strengthening the requirements for verifying the effectiveness of dust control plans, and in enforcing effective plans through the new enforcement policy proposed in this notice, is to ensure that no miner is exposed to an excessive concentration (
Based on 1999 operator data, there were 704 MMUs (out of 1,251 total) at which dust concentrations for the designated occupation (DO) exceeded the applicable standard on at least two of the sampling shifts (MSHA, Datafile:Operator.ZIP).
These results are based on a large number of shifts (an average of approximately 26 at each of the 704 MMUs). Therefore, assuming representative operating conditions on these shifts, the results can be extrapolated to all production shifts, including those that were not sampled, at these same 704 MMUs. With 99-percent confidence, the overall percentage of production shifts on which the DO sample exceeded the standard was between 20.6 percent and 22.2 percent for 1999. At the same confidence level, again assuming representative operating conditions, the overall mean excess on noncompliant shifts at these MMUs was between 0.96 mg/m
In 1998, MSHA attempted to enforce compliance on individual shifts. Therefore, to compare the 1999 pattern of excess exposures on individual shifts to that of previous years under the current enforcement policy, MSHA examined the regular bimonthly DO sample data submitted to MSHA by mine operators in the eight years from 1990 through 1997. The same three parameters were considered as discussed above for 1997: (1) The percentage of MMUs exhibiting a pattern of recurrent overexposures, as indicated by at least two of the valid measurements above the applicable standard in a given year; (2) for those and only those MMUs exhibiting recurrent overexposures, the overall percentage of production shifts on which the DO was overexposed, as estimated by the percentage of valid measurements above the applicable standard; and (3) for the MMUs identified as exhibiting recurrent overexposures, the mean excess above the applicable standard, as calculated for just those valid measurements that exceeded the applicable standard in a given year.
Although MSHA found minor differences between individual years, there was no statistically significant upward or downward trend in any of these three parameters over the 1990–1997 time period (see Table VI–1). In 1999, however, there was a significant decrease in the average excess above the applicable standard (Parameter #3) for MMUs exhibiting recurrent overexposures. MSHA attributes this decrease to two important changes in the Agency's inspection program, beginning near the end of 1998. These changes, which both resulted in increased inspector presence, were: (1) An increase in the frequency of MSHA dust sampling at underground coal mines; and (2) initiation of monthly spot inspections at mines that were experiencing difficulty in maintaining consistent compliance with the applicable dust standard.
MSHA invites public comment on whether these three parameters, based on operators' 1999 samples, under-represent or over-represent the frequency and/or magnitude of excessive dust concentrations on
• Approximately 56 percent of all MMUs would continue to have a pattern of recurrent overexposures on individual shifts;
• At those MMUs with recurrent overexposures, full shift average respirable dust concentrations for the DO would continue to exceed the applicable standards on about 21 percent of all production shifts;
• Among those shifts on which DO exposure exceeds the applicable standards, the mean excess for the DO would continue to be
If all overexposures on individual shifts are eliminated, the reduction in total respirable coal mine dust inhaled by a miner over a working lifetime will depend on the following factors: the average volume of air inhaled on each shift that would otherwise have exceeded the applicable standard, the degree of reduction in respirable dust concentration in the air inhaled on such shifts, and the number of such shifts per working lifetime. If a miner inhales ten cubic meters of air on a shift (U.S. EPA, 1980), reducing the respirable dust concentration in that air by 1.0 mg/m
The Secretaries invite comments on the health benefits expected from reducing the total coal mine dust inhaled over a working lifetime by this amount.
In Section V, the strengths and weaknesses of various epidemiological studies were presented, supporting the selection of Attfield and Seixas (1995) as the study that provides the best available estimate of material health impairment with respect to CWP and PMF. Two of the distinguishing qualities of this study are the dose-response relationship over a miners' lifetime and the fact that these data best represent the recent conditions experienced by miners in the U.S. Using this relationship it is possible to evaluate the impact on risk of both simple CWP and PMF expected from bringing dust concentrations down to or below the applicable standard on every shift. This is the only contemporary epidemiological study of CWP and PMF providing such a relationship.
Attfield and Seixas used two or three B readers to identify the profusion of opacities using the ILO classification scheme. If three readings were available, the median value was used. If two readings were available, the higher of the two ILO categories was recorded. Eighty radiographs were eliminated because only one reading was available. The most inclusive category of CWP 1
Attfield and Seixas (1995) provided logistic regression models for the prevalence for CWP 1
At the MMUs being considered (those exhibiting a pattern of recurrent overexposures), bringing dust concentrations down to no more than the applicable standard on each and every production shift would reduce DO exposures on the affected shifts by an average of 1.04 mg/m
The Attfield and Seixas models predict the prevalence of CWP 1
This 11 per thousand, however, applies only to miners of age 65. The Attfield and Seixas models provide different predictions for each year of age that a miner attains. The predicted benefit turns out to be smaller for younger miners and larger for older miners. This is partly because younger miners will have accumulated less exposure reduction from the proposed changes, and partly because the Attfield and Seixas models depend directly on age as well as on cumulative exposure. The health effects of recurrent overexposures can occur long after the overexposures occurred. Even after a miner retires and is no longer exposed to respirable coal mine dust, the extra risk attributable to an extra 10 mg-year/m
To project the benefits of the two rules expected from eliminating overexposures on individual shifts, MSHA applied the Attfield and Seixas models to a hypothetical population of miners who, on average, begin working at age 20 and retire at age 65, assuming different lifetimes. The risks for three different ages have been presented to show a range of risk depending on the lifetime: 65, 73, and 80 years. During the 45 “working years” between 20 and 65, the lifetime benefit accumulates at a rate of 0.22 mg-yr/m
The expected lifetime for all American males conditional on their having reached 20 years of age, is 73 years (calculated from: U.S. Census March 1997, Table 18; U.S. Census March 1997, Table 119).
• Reduce the combined risk of simple CWP and PMF by at least 18 cases per 1000 affected DO miners;
• Reduce the combined risk of simple CWP (category 2 and 3) and PMF by at least 9.8 cases per 1000 affected DO miners;
• Reduce the risk of PMF by at least 5.1 cases per 1000 affected DO miners.
Presented in the first row of Table VI–2 are the average reductions in risk for simple CWP and PMF combined, and PMF alone, over an occupational lifetime, among affected DO miners who live to ages 65, 73, and 80, who have worked at an MMU exhibiting a pattern of recurrent overexposures. Across health outcomes, the benefit due to the predicted reduction in cumulative exposure to respirable coal mine dust, through limiting miners' exposure to no more than the applicable standard on each and every shift, increases with age.
When the dust concentration measured for the DO exceeds the applicable standard, measurements for at least some of the other miners may also exceed the standard on the same shift, though usually by a lesser amount. Furthermore, although the DO represents the occupation most likely to receive the highest exposure, other miners working in the same MMU may be exposed to even higher concentrations than the DO on some shifts. Therefore, in addition to the affected DO miners, there is a population of other affected miners who are also expected to experience a significant reduction in risk as a result of eliminating overexposures on their individual shifts.
To estimate how many miners other than the DO would be substantially affected, MSHA examined the results from all valid dust samples collected by MSHA inspectors in underground MMUs during 1999 (MSHA, Data file: Inspctor.zip). Within each MMU, the inspector typically takes one full-shift sample on the DO and, on the same shift, four or more additional samples representing other occupations. On 896 shifts, at a total of 450 distinct MMUs, the DO measurement exceeded the applicable standard and there were at least four valid measurements for other
Combining these results with the 21-percent rate of excessive exposures observed for the DO on individual shifts, it is reasonable to infer that, at the MMUs under consideration, an average of 1.2 other miners, in addition to the one classified as DO, is overexposed on at least 21 percent of all production shifts. Over the course of a working year, the reduction in exposure expected for these other miners is 0.17 mg-yr/m
To assess the reduction in risk expected from eliminating all single-shift exposures for faceworkers experiencing lower exposures than the DO, MSHA again applied the Attfield and Seixas models to miners who begin working at age 20, retire at age 65, assuming various lifetimes: 65, 73, and 80 years. This time, however, the resulting decrease in predicted prevalence was multiplied by 1.2/7=0.171, to reflect the fact that the assumed rate of overexposure applies, on average, to about 17 percent of the faceworkers not classified as the DO.
In the second row of Table VI–2, we see that over an occupational lifetime, the beneficial average reduction in risk for simple CWP and PMF combined, and for PMF alone, increases with age. However, the magnitude of the risk reduction is smaller for the affected non-DOs than the affected DOs. This is expected because the estimated probability that a non-DO will be overexposed on a given shift is only 17 percent of the corresponding probability for the DO. Based on this calculation for the MMUs under consideration, the predicted reduction in risk for faceworkers other than the DO who live an expected lifetime of 73 years is at least: 2.3 fewer cases of PMF or simple CWP per thousand affected miners; 1.3 fewer cases of PMF or simple CWP, categories 2 or 3, per thousand affected miners; and 0.7 fewer cases of PMF per thousand affected miners.
Various data, assumptions and caveats were used to conduct the quantitative risk assessment and benefits analyses. Therefore, we request any information which would enable us to conduct more accurate analyses of the estimated health benefits of the single, full-shift sample rule and plan verification rule, both individually and in combination.
The criteria for evaluating the evidence to determine whether these proposed standards improve the regulatory strategy for controlling exposures to respirable coal mine dust are established by the Mine Act pursuant to section 101(a)(6)(A) (30 U.S.C. 811(a)(6)(A))which provides that:
The Secretary, in promulgating mandatory standards dealing with toxic materials or harmful physical agents under this subsection, shall set standards which most adequately assure on the basis of the best available evidence that no miner will suffer material impairment of health or functional capacity even if such miner has regular exposure to the hazards dealt with by such standard for the period of his working life.
Based on Court interpretations of similar language under the Occupational Safety and Health Act, there are three questions that must be addressed: (1) Whether health effects associated with the current pattern of overexposures on individual shifts constitute a material impairment to miner health or functional capacity; (2) whether the current pattern of overexposures on individual shifts places miners at a significant risk of incurring any of these material impairments; and (3) whether the proposed rules would substantially reduce those risks.
The statutory criteria for evaluating the health evidence do not require MSHA to wait for absolute certainty and precision. MSHA is required to use the “best available evidence” (section 101(a)(6)(A) of the Mine Act (30 U.S.C. 811(a)(6)(A)). The need to evaluate risk does not mean that an agency is placed into a “mathematical straightjacket.”
We have taken steps in our quantitative risk assessment to conduct a balanced analysis using available data. Some of our assumptions were conservative, others were not.
In identifying the number and percentage of MMUs exhibiting a pattern of recurrent overexposures on individual shifts we chose to include only those MMUs with two or more 1999-operator bimonthly samples in excess of the applicable standard, rather than the population of MMUs with any overexposures.
Another important decision impacting choice in this risk assessment involves the use of the traditional coal miner work schedule of 48-weeks per year. Many of today's miners work longer hours per day, month, and year than the traditional work schedule. These longer work hours increase miners' cumulative exposure to respirable coal mine dust beyond the parameters of exposure used in our estimates of risk. Even so, to the extent that a proportion of miners may have a more limited work schedule (and occupational exposure), either in number of years, weeks per year, or hours per week, their expected benefit would have to be adjusted downward, all other variables being constant.
Also, because of heavy, physical work, some miners may work at ventilatory rates in excess of the above-cited 10 cubic meters per 8-hour shift; an estimate of this ventilatory rate is 13.5 cubic meters per 8-hour shift (ICRP, 1994). The sub-population of miners with higher breathing rates would inhale more respirable coal mine dust than would otherwise occur given the same environmental exposures, thereby increasing their risks for the development of simple CWP and PMF.
In the QRA, to estimate average reduction in exposure, we chose the best available data sets: 1999 operator bimonthly samples for DOs and NDOs, respectively. Currently, both operator bimonthly and inspector samples
Based on MSHA's and NIOSH's experience and expertise, and previous comments, we believe the production levels observed on sampling shifts are indeed lower than typical (See discussion in Benefits section). We also believe at some MMUs, more engineering controls at higher levels of efficacy are used during sampling shifts than on the majority of shifts (See discussion in Benefits section). Thus, it is reasonable to conclude that the number of MMUs exhibiting a pattern of recurrent overexposures is greater than the 704 captured in this Quantitative Risk Assessment. Furthermore, the severity and rate of overexposures to respirable coal mine dust among the 704 MMUs exhibiting a pattern of recurrent overexposures are probably also greater than we have estimated. We have derived our best estimate of the reduced risk using the best available data. Yet due to limitations in the data, we believe that we have underestimated the magnitude and frequency of typical respirable coal mine exposures. To the extent that our values underestimate the true reduction in respirable coal mine dust exposures, we have underestimated the benefits of these rules.
Other aspects of our risk assessment methodology reflect more conservative choices including the selection of an occupational lifetime of 45-years. Various factors may affect the consistency of the type and duration of jobs miners hold and hence their associated cumulative exposure levels. For example, some miners who lose their jobs upon mine closure are employed by other mines, sometimes in less-exposed jobs. Some miners may chose to move from job to job over their careers at underground coal mines, sometimes preferring positions away from the mining face. Moreover, if the trend of increasing mechanization continues, there will be fewer miners, and for some of them, their occupational lifetimes will be shorter.
For reasons already explained, we believe these choices are appropriate for this risk assessment. We also recognize that use of the most conservative approach at every step of the risk assessment analysis could produce mathematical risk estimates which, because of the additive effect of multiple conservative assumptions, may overstate the likely risk. We believe this QRA for simple CWP and PMF strikes a reasonable balance based on available data. To the extent that we may have underestimated the magnitude of overexposures which would be prevented, we believe the actual benefits to be greater than we have estimated.
It should be noted that reductions in the prevalence of simple CWP and PMF attributable to eliminating individual shift overexposures are not expected to materialize immediately after the overexposures have been substantially reduced or eliminated. Because these diseases typically arise after many years of cumulative exposure, allowing for a period of latency, the beneficial effects of reducing exposures are expected to become evident only after a sufficient time has passed that the reduction in cumulative exposure could have its effect. The total realized benefits would not be fully evident until after the youngest of today's underground coal miners retire.
Section 101(a)(6)(A) of the Mine Act (30 U.S.C. 811(a)(6)(A)) requires the Secretary of Labor to set standards which most adequately assure, on the basis of the best available evidence, that no miner will suffer material impairment of health or functional capacity even if such miner has regular exposure to such hazards dealt with by
In relation to promulgating health standards, the legislative history of the Mine Act states that:
* * * This section further provides that “other considerations” in the setting of health standards are “the latest available scientific data in this field, the feasibility of the standards, and experience gained under this and other health and safety laws.” While feasibility of the standard may be taken into consideration with respect to engineering controls, this factor should have a substantially less significant role. Thus, the Secretary may appropriately consider the state of the engineering art in industry at the time the standard is promulgated.
In
MSHA believes that the plan verification rule would be technologically feasible for the mining industry. An agency must show that modern technology has at least conceived some industrial strategies or devices that are likely to be capable of meeting the standard, and which industry is generally capable of adopting.
In designing the plan verification rule, MSHA has taken into account its experience and those of the operators to ensure that the rule provides additional protection from occupational exposure to respirable coal mine dust using current compliance technology (while encouraging technological improvements). For this reason, MSHA believes the proposed plan verification rule is technologically feasible. MSHA requires mine operators to utilize all
Based on its vast experience in the sampling of respirable dust levels in the MMU work environment, MSHA believes that technology is currently available to control respirable dust to levels at or below the applicable level 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 downwind along the face. In these high-production longwall MMUs, improvements in dust control technology have not kept pace with increases in production technology. For this reason, the proposed plan verification rule would allow longwall operators who have trouble in meeting MSHA's respirable dust standard and who have exhausted all feasible engineering and environmental controls to use administrative controls or loose-fitting powered air-purifying respirators (PAPRs), until other feasible controls become available.
The plan verification rule would clearly be economically feasible for the underground coal mining industry since the underground coal mining industry would derive net compliance cost savings of approximately $2.04 million yearly from the proposed plan verification rule. (Although implementing the plan verification rule would cost about $4.75 million yearly, there would be the following offsetting yearly savings: $2.19 million from reduced mine operator citations based on results from inspector single, full-shift samples and associated abatement sampling, $1.61 million from reduced mine operator citations on results from operators' bi-monthly samples and associated abatement sampling, $2.73 million from the elimination of operator bi-monthly sampling, and $0.27 million from reduced payouts by mine operators for Black Lung cases.) Underground coal mine operators would also obtain a yearly cost savings of approximately $0.42 million in reduced penalty costs associated with the reduction in mine operator citations arising from the proposed plan verification rule. The proposed plan verification rule would therefore provide a total yearly cost savings of about $2.46 million to the underground coal mining industry.
MSHA's improved program to eliminate overexposures on each and every shift includes (1) the simultaneous implementation of the use of inspector single, full-shift respirable coal mine dust samples to identify overexposures more effectively in both underground and surface coal mines (single, full-shift sample), and (2) in underground coal mines, verified ventilation plans to maintain miners' respirable dust exposure at or below the applicable standard on each and every shift (plan verification). The single, full-shift sample NPRM is published elsewhere in today's
Assumptions for the requirements of the plan verification rule are based upon information provided by MSHA technical personnel. We encourage the mining community to provide detailed comments in this regard to ensure that plan verification cost assumptions and estimates are as accurate as possible.
In accordance with Executive Order 12866, we have prepared a detailed PREA of the estimated costs and benefits associated with the proposed rule for the underground coal mining sector. We have fulfilled this
The proposed plan verification rule would provide yearly
Table IX–1 summarizes the estimated net compliance costs by provision for underground coal mines, for the following three mine size categories: (1) those employing fewer than 20 workers; (2) those employing between 20 and 500 workers; and (3) those employing more than 500 workers.
In addition to these estimated compliance costs, mine operators would derive yearly penalty cost reductions of about $0.4 million (See Table IX–1(a)). Penalty costs conventionally are not considered to be a cost of a rule (and, in fact, are clearly not a compliance cost) but merely a transfer payment from a party violating a rule to the government. Therefore, the penalty costs are not included as part of the compliance costs of the proposed plan verification rule. These penalty costs are relevant, however, in determining the economic feasibility of the proposed plan verification rule.
The derivation of the above cost figures are presented in Chapter IV of the PREA that accompanies this rule.
Occupational exposure to excessive levels of respirable coal mine dust imposes significant health risks. These include the following adverse health outcomes: simple coal worker's pneumoconiosis (simple CWP), progressive massive fibrosis (PMF), silicosis, and chronic obstructive pulmonary disease (COPD) (e.g., asthma, chronic bronchitis, emphysema) (See the Health Effects section for details). Cumulative exposure to respirable coal mine dust is the main determinant in the development of both simple CWP and PMF although other factors such as the percentage of quartz in the respirable dust and the type of coal also affect the risk of miners developing simple CWP and PMF (Jacobsen,
Through the joint promulgation of single, full-shift sample and plan verification rules, 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 and every shift.
Based on 1999 operator data, there were 704 MMUs (out of 1,251) at which regular (not abatement) designated occupational (DO) samples exceeded the applicable standard on at least two of the sampling shifts reported in 1999 (MSHA, Data file:Operator.ZIP). MSHA considers these 704 MMUs, representing more than one-half of all underground coal miners working in production areas, to have exhibited a pattern of recurrent overexposures. Based on valid DO operator samples were collected on a total of 18,569 shifts at these 704 MMUs; the applicable standard was exceeded on 3,977 of these shifts or 21.4 percent.
At the MMUs being considered (those exhibiting a pattern of recurrent overexposures),
When the dust concentration measured for the DO exceeds the applicable standard, measurements for at least some of the other miners working in the same MMU may also exceed the standard on the same shift, though usually by a smaller amount. Furthermore, although the DO represents the occupation most likely to receive the highest exposure, other miners working in the same MMU may be exposed to even higher concentrations than the DO on some shifts. Therefore, in addition to the affected DO miners, there is a population of other affected miners who are also expected to experience a significant reduction in risk as a result of eliminating overexposures on their individual shifts.
To estimate how many miners other than the DO would be substantially affected, MSHA examined the results from all valid dust samples collected by MSHA inspectors in underground MMUs during 1999 (MSHA, Data file: Inspctor.zip). Within each MMU, the inspector typically takes one full-shift sample on the DO and, on the same shift, four or more additional samples representing other occupations. On 896 shifts, at a total of 450 distinct MMUs, the DO measurement exceeded the applicable standard and there were at least three valid measurements for other occupations available for comparison. There was an average of 1.2 non-DO
Combining these results with the 21-percent rate of excessive exposures observed for the DO on individual shifts, it is reasonable to infer that, at the MMUs under consideration, an average of 1.2 other miners, in addition to the one classified as DO, is overexposed on at least 21 percent of all production shifts. Over the course of a working year, the reduction in exposure expected for these affected non-designated occupational (NDO) miners, is 0.17 mg-yr/m
The expected lifetime for all American males, conditional on their having reached 20 years of age, is 73 years (U.S. Census March 1997, Table 18; U.S. Census March 1997, Table 119).
To estimate the benefits (i.e., number of cases of simple CWP and PMF prevented) of single, full-shift sample and plan verification combined, we applied these estimates of risk reduction to the estimated sub-populations of affected miners. As of February 12, 1999, there were 984 producing MMUs;
The benefits that will accrue to coal miners exposed to respirable coal mine dust and to mine operators, and ultimately to society at large, are substantial and take a number of forms. These proposed rules would reduce a significant health risk to underground coal miners, reducing the potential for illnesses and premature death and their attendant costs to miners, their employers, their families, and society.
The joint promulgation of these rules should realize a positive economic impact on the Department of Labor's (DOL's) Black Lung Program and relatedly on mine operators. The Black Lung Program compensates
Table IX–2 presents the estimated number of cases of simple CWP and PMF that would be prevented among the 56 percent of MMUs exhibiting a pattern of recurrent overexposures. For all categories of simple CWP and PMF combined, we estimate 37 fewer of these cases, among affected miners, than would otherwise occur without the promulgation of single, full-shift sample and plan verification rules. Eleven of these cases would be the most severe form of coal miners pneumoconiosis, PMF, and as such this benefit could be interpreted as prevented premature deaths due to occupational exposure to respirable coal mine dust. Since simple CWP predisposes the development of PMF, it is important that it also be prevented (Balaan,
As discussed in the Significance of Risk sections, MSHA believes this QRA for simple CWP and PMF strikes a reasonable balance based on available data. Yet, our estimates likely understate the true impact of these rules since our analyses are restricted to a sub-population of affected miners, those working at MMUs exhibiting a pattern of recurrent overexposures, not the broader population of coal miners who will benefit from these rules. Furthermore, to estimate the average
The degree to which the exposure level of respirable coal mine dust on sampling shifts may not be representative of typical exposure levels is affected by the following factors:
(1) There exists a positive relationship between coal production and generation of respirable coal mine dust;
(2) Current sampling procedures permit sampling measurements to be taken at the mid-range of the distribution of level of production—sampling measurements must be taken on shifts with production at least 60% of the average production during the last 30 days and at least 50% of average production for the last valid set of bimonthly samples for inspector and operator samples, respectively;
(3) Miners have reported and MSHA data have demonstrated lower levels of production on sampling shifts versus non-sampling shifts (MSHA, September 1993);
(4) On some sampling shifts, miners have reported that more engineering controls may be used than on other shifts, thus reducing the measured amount of respirable coal mine dust;
(5) MSHA analyses have demonstrated, even when controlling for production, in mines with fewer than 125 employees, on continuous mining MMUs, respirable coal mine dust exposures were much higher during the unannounced Spot Inspection Program (SIP) sampling shifts than on shifts operators sampled—this is consistent with the effect of increasing engineering controls on shifts during which bimonthly samples are conducted compared to the level of use of engineering controls used on shifts for which the operator does not expect sampling to be conducted given the same production level (Denk, 1993);
(6) Across mine size, designated area samples have been found to be larger for shifts on which unannounced compliance sampling occurred compared to operator sampling shifts— in one study they differed by at least a factor of 40 percent in large mines and 100 percent in the smallest mines (ibid. p 211–212); and
(7) Existing MSHA technical information indicates that some reduction in production levels occurs during some sampling periods on longwalls (Denk, 1990).
Therefore, at a bare minimum, over an occupational lifetime (45-years) for miners who live to age 73 who worked at MMUs exhibiting a pattern of recurrent overexposures, we estimate at least 37 fewer cases of pneumoconiosis (simple coal workers pneumoconiosis (CWP) and progressive massive fibrosis (PMF)) than would otherwise occur without the promulgation of these rules.
Our current quantitative estimate of benefits demonstrates and qualitative discussions punctuate that these rules will have a significant positive impact on the health of our Nation's coal miners when promulgated. Yet,
MSHA believes that cases of simple CWP and PMF would also be prevented among other types of underground miners, such as roofbolters working in designated areas (DA). Based on MSHA experience it is reasonable to expect roofbolter DA's pattern of overexposures for respirable coal mine dust to be similar to that for miners with the highest exposure on an MMU. If so, we would expect 13 additional cases of simple CWP and PMF to be prevented. Affected DAs include DAs who work at the 56 percent of the MMUs under consideration who are exposed to dust concentrations similar to the DO, over a 45-year occupational lifetime (MSHA Table, November 18, 1999; MSHA Table, February 12, 1999).
Although the effect cannot readily be quantified, to the extent that these rules would also reduce the cumulative exposure to respirable coal mine dust among some miners working in those MMUs not exhibiting overexposures, it is reasonable to expect that we would observe an incremental benefit among that sub-population of coal miners. Moreover, to the extent that the cumulative dust exposure is reduced for miners working in the “out by” areas, away from the mining face (i.e., MMU) where coal is extracted from the coal seam, they too may realize occupational health benefits due to the simultaneous promulgation of these proposals. Therefore, our best estimate of 37 prevented cases of simple CWP and PMF, combined, among all affected miners
Clearly PMF is associated with premature death. Since simple CWP may evolve to PMF, even after occupational exposure has ceased, it has the propensity to become a life threatening illness. By reducing the total number of simple CWP and PMF cases among affected miners from 259 to 222, over 45 years, these standards, at a minimum, are projected to prevent an average of four cases of simple CWP and PMF for each 5-year interval.
For all those reasons previously identified, MSHA believes that its estimate of 37 prevented cases of simple CWP and PMF over a 45 year working life understates the true number of cases of simple CWP and PMF which would be prevented. This belief is further supported by the fact that during the past few years, the Black Lung Benefits Program has been approving roughly 400 claims each year. These claims come from individuals whose exposure for the most part came after the current standard of 2.0 was established in 1972. Thus, we believe the consistent annual approval by the Black Lung Benefits Program, of hundreds of new cases of simple CWP and PMF per year, supports our belief that the true lifetime occupational health benefits of the proposed rules are higher than we have estimated. Even assuming that the number of new claims would decline in future years simply due to the continuing decline in the number of coal miners, MSHA expects that assuring that future exposures are maintained below the 2.0 exposure limit will reduce the number of new cases of simple CWP and PMF by considerably more than 1 per year.
In addition to the prevention of simple CWP and PMF, each of the 8,640 affected miners at MMUs exhibiting a pattern of recurrent overexposures will realize some health benefit by limiting his or her cumulative exposure to respirable coal mine dust to no more than the applicable standard on each and every shift.
The expected number of prevented cases of simple CWP and PMF would not be realized for some time even after the pattern of overexposures has been minimized or eliminated. This is due, in part, to the latency—that is, the disease does not develop immediately after exposure—of the development of simple CWP and PMF and the pre-existing occupational exposure histories of members of the current coal mining workforce. Our estimated benefit is based on the estimated number of underground coal miners working at the mine face, 17,280. If the size of this workforce significantly changed in the future and the projected pattern of prevented overexposures remained the same, the number of cases of prevented
Various data, assumptions and caveats were used to conduct the quantitative risk assessment, significance of risk discussion, and benefits analyses. Therefore, we request any information which would enable us to conduct more accurate analyses of the estimated health benefits of the single, full-shift sample rule and plan verification rule, both individually, and in combination.
The Regulatory Flexibility Act requires MSHA to conduct an analysis of the effects of the proposed plan verification rule on small entities. That analysis is summarized here; a copy of the full analysis is included in Chapter V of our PREA in support of the proposed single, full-shift sample and plan verification rules. We encourage the mining community to provide comments on this analysis.
The Small Business Administration generally considers a small entity in the mining industry to be one with 500 or fewer workers. MSHA has traditionally defined a small mine to be one with fewer than 20 workers, and has focused special attention on the problems experienced by such mines in implementing safety and health rules. Accordingly, we have separately analyzed the impact of the joint notice proposed rule both on mines with 500 or fewer workers and on those with fewer than 20 workers.
Pursuant to the Regulatory Flexibility Act, MSHA must determine whether the costs of the joint notice proposed rule constitute a “significant impact on a substantial number of small entities.” Pursuant to the Regulatory Flexibility Act, if an Agency determines that a proposed rule would not have such an impact, it must publish a “certification” to that effect. In such a case, no additional analysis is required (5 U.S.C. § 605). In evaluating whether certification is appropriate, MSHA utilized a “screening test,” comparing the costs of the proposed plan verification rule to the revenues of the affected coal sector. If the estimated costs are less than 1 percent of revenues for the affected entities, or they are negative (that is, they provide a cost savings), then the rule is assumed not to have a significant impact on small mine operators.
Table IX–3 compares, for small underground coal mines (using both MSHA's and SBA's definition), MSHA's estimated total annual compliance costs of the proposed plan verification rule to estimated annual revenues.
Table IX–3 shows that under either MSHA's or SBA's definition of a small mine, the proposed plan verification rule would provide a net cost savings to small underground coal mines. As a result, MSHA is certifying that the proposed plan verification rule for underground coal mines would not have a “significant impact on a substantial number of small entities,” and has performed no further analyses.
We (MSHA) wrote appropriate portions of this proposed rule in the more personal style advocated by the President's Memorandum on “plain language.” “Plain language” encourages the use of personal pronouns (we and you); sentences in the active voice; a greater use of headings, lists, and questions, as well as charts, figures, and tables.
In this proposed rule, “you” refers to production-operators and independent contractors because they have the primary responsibility for compliance with MSHA regulations. In addition, we recognize and appreciate the value of comments, ideas, and suggestions from labor organizations, industry associations, and other parties who have an interest in health and safety training for miners.
We would appreciate comments and suggestions from all parties on this proposed rule and on our use of “plain language.” How could we improve the clarity of this style?
For purposes of the Unfunded Mandates Reform Act of 1995, this rule does not include any Federal mandate that may result in increased expenditures by State, local, and tribal governments, or increased expenditures by the private sector of more than $100 million.
The proposed plan verification rule contains information collections which are subject to review by the Office of Management and Budget (OMB) under the Paperwork Reduction Act of 1995 (PRA95). The proposed rule has first year burden hours (those that occur
How some types of burden hours and costs were handled requires explanation. In a few cases, the proposed plan verification rule imposes burden hours and costs that would be the same every year, beginning with the first year that the rule takes effect. These are “annual” burden hours and costs, as traditionally defined.
In most cases, however, the proposed plan verification rule imposes burden hours and costs which would be the same each year starting with the second year the proposed rule is in effect, but whose first year burden hours and costs would be different. MSHA transformed these first year burden hours and costs and annual burden hours and costs starting in Year 2 into adjusted first year burden hours and costs (first year burden hours and costs minus an amount equal to annual burden hours and costs starting with Year 2 after the rule takes effect) and true annual burden hours and costs starting in Year 1 after the rule takes effect.
In the first year the plan verification rule is in effect, there would be a total
There would be a total
We invite public comments and are particularly interested in comments which:
1. Evaluate whether the proposed collection of information (presented here and in the PREA for the proposed single, full-shift sample and plan verification rules) is necessary for the proper performance of the functions of MSHA, including whether the information will have practical utility;
2. Evaluate the accuracy of our estimate of the burden of the proposed collection of information, including the validity of the methodology and assumptions used;
3. Enhance the quality, utility, and clarity of the information to be collected; and
4. Minimize the burden of the collection of information on respondents, including through the use of appropriate automated, electronic, mechanical, or other technological collection techniques or other forms of information technology,
We have submitted a copy of this proposed rule to OMB for its review and approval of these information collections. Interested persons are requested to send comments regarding this information collection, including suggestions for reducing this burden, to the Office of Information and Regulatory Affairs, OMB New Executive Office Building, 725 17th St., NW, Rm. 10235, Washington, DC 20503, Attn: Desk Officer for MSHA. Submit written comments on the information collection not later than September 5, 2000.
Our paperwork submission summarized above is explained in detail in the PREA. The PREA includes the estimated costs and assumptions for each proposed paperwork requirement related to this proposed rule. A copy of the PREA is available from us. These paperwork requirements have been submitted to the Office of Management and Budget for review under section 3504(h) of the Paperwork Reduction Act of 1995. Respondents are not required to respond to any collection of information unless it displays a current valid OMB control number.
The National Environmental Policy Act (NEPA) of 1969 requires each Federal agency to consider the environmental effects of proposed actions and to prepare an Environmental Impact Statement on major actions significantly affecting the quality of the human environment. We have reviewed the proposed standard in accordance with the requirements of the NEPA (42 U.S.C. 4321
Commenters are encouraged to submit their comments on this determination.
This proposed rule is not subject to Executive Order 12630, Governmental Actions and Interference with Constitutionally Protected Property Rights, because it does not involve implementation of a policy with takings implications.
The Agency has reviewed Executive Order 12988, Civil Justice Reform, and determined that this rulemaking will not unduly burden the Federal court system. The regulation has been written so as to provide a clear legal standard for affected conduct, and has been reviewed carefully to eliminate drafting errors and ambiguities.
In accordance with Executive Order 13045, protection of children from environmental health risks and safety risks, we have evaluated the environmental health or safety effects of the proposed rule on children. The Agency has determined that this proposal would not have an adverse impact on children.
We certify that this proposed rule does not impose substantial direct compliance costs on Indian tribal governments.
We have reviewed this rule in accordance with Executive Order 13132 regarding federalism, and have determined that it does not have “federalism implications.” The rule does not “have substantial direct effects on the States, on the relationship between the national government and the States, or on the distribution of
MSHA plans to hold public hearings on the proposed rule. The hearings will be held in 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
All measurements of respirable dust concentration are subject to potential sampling and analytical errors. Because of such errors, a measurement may fall slightly below the verification limit even when the true concentration of respirable coal mine dust or crystalline silica does not. Therefore, to ensure that the verification limits have actually been met, it is necessary to provide for a margin of error in each measurement. The critical values provide this margin of error. When valid measurements do not exceed the appropriate critical values, we can be confident that the verification limits have not been exceeded at the sampled locations.
To explain how the verification limits were derived, it is helpful to define some symbolic notation. Let X represent a measurement, and let μ represent the true value of whatever quantity is being measured—i.e., the full shift average concentration, at a specific sampling location, of either respirable coal mine dust or respirable crystalline silica dust. The difference between X and μ is the measurement error and is denoted by ε. X = μ + ε.
In accordance with standard statistical and industrial hygiene practice, ε (but not μ) is assumed to be normally distributed. Since the approved sampling and analytical methods for measuring concentrations of respirable coal mine dust and respirable silica dust are both statistically unbiased, ε has a mean value of zero and a degree of variability represented by its standard deviation, denoted by σ
For respirable coal mine dust, the value of CV used in calculating critical values was chosen to be consistent with the value proposed at μ = 2.0 mg/m
For respirable silica dust, the value of CV used in calculating critical values is:
Each critical value (c) was calculated to provide a confidence level of at least 95 percent that the ventilation plan was effective in preventing dust concentrations from exceeding the verification limits. Using a confidence coefficient of 1.645, based on the standard normal probability distribution, knowledge of the CV makes it possible to calculate a 1-tailed, 95-percent upper confidence limit (UCL) for μ, given a single measurement X. The UCL is X·(1 + 1.645·CV). When X ≤ c, the UCL for μ is less than or equal to the verification limit. When X > c, the UCL for μ exceeds the verification limit.
For example, suppose X = 1.71 mg/m
If more than one measurement is available, then the confidence coefficient changes to reflect multiplication of the tail probabilities for independent measurement errors. When n measurements are available, the objective is to calculate a critical value (c) such that if each of the n measurements is ≤ c, then the 1-tailed 95-percent UCL for μ is ≤ the verification limit. Since the product of the n individual tail probabilities must equal 0.05, the appropriate 1-tail probability for each measurement individually is the n
For example, if n = 3, then the appropriate 1-tail probability for each measurement is the cube root of 0.05, or 0.3684. The standard normal confidence coefficient corresponding to this tail probability is 0.336. Therefore, when all three measurements have the same value (X), the UCL is X·(1+0.336·CV). Substituting the appropriate CV estimate, the UCL is X·1.0336 for coal mine dust or X·1.0302 for crystalline silica. Consequently, to obtain the critical value, the verification limit is first divided by 1.0336 (coal mine dust) or 1.0302 (crystalline silica dust) and then truncated to the desired number of decimal digits. This yields 1.93 mg/m
The confidence coefficients used to establish critical values by this method are as follows:
It should be noted that although the critical value calculated for n ≥ 4 is slightly below the verification limit for both types of dust, for simplicity it was set equal to the verification limit as a close approximation.
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Accordingly, it is proposed to amend Chapter I of Title 30 of the Code of Federal Regulations as follows:
1. The authority citation for part 70 continues to read as follows:
30 U.S.C. 811, 813(h), 957 and 961, unless otherwise noted.
2. Section 70.2 is revised to read as follows:
(a)
(b)
(c)
(d)
(e)
(f)
(g)
(h)
(i)
(j)
(k)
(l)
(m)
(n)
(o)
(p)
(q)
(r)
(s)
(t)
(1) With regard to a mechanized mining unit, a shift during which material is produced, or
(2) With regard to a designated area of a mine, a shift during which material is produced and routine day-to-day activities are occurring in the designated area.
(u)
(v)
(w)
(x)
(y)
(1) Can be reviewed to confirm its proper implementation,
(2) Is clearly understood by miners, and
(3) Can be applied consistently over time.
(z)
(aa)
(bb)
3. Subpart B is revised to read as follows:
30 U.S.C. 811 and 813(h).
When quartz is not present:
(a) Each operator shall continuously maintain the average concentration of respirable dust in the mine atmosphere during each shift to which each miner in the active workings of each mine is exposed at or below 2.0 milligrams of respirable dust per cubic meter of air as measured with an approved sampling device and in terms of an equivalent concentration determined in accordance with § 70.2(c).
(b) Each operator shall continuously maintain the average concentration of respirable dust within 200 feet outby the working faces of each section in the intake airways at or below 1.0 milligrams of respirable dust per cubic meter of air as measured with an approved sampling device and in terms of an equivalent concentration determined in accordance with § 70.2(c).
When the respirable dust in the mine atmosphere of the active workings contains more than 5 percent quartz as determined by samples taken by the Secretary, the operator shall continuously maintain the average concentration of respirable dust in the mine atmosphere during each shift to which each miner in the active workings is exposed at or below a concentration of respirable dust, expressed in milligrams per cubic meter of air as measured with an approved sampling device and in terms of an equivalent concentration determined in accordance with § 70.2(c), computed by dividing the percent of quartz into the number 10.
Example: The respirable dust associated with a mechanized mining unit or a designated area in a mine contains quartz in the amount of 20%. Therefore, the average concentration of respirable dust in the mine atmosphere associated with that mechanized mining unit or designated area shall be continuously maintained at or below 0.5 milligrams of respirable dust per cubic meter of air (10/20=0.5 mg/m
4. Subpart C is revised to read as follows:
30 U.S.C. 811, 813(h), and 957.
All underground coal mine operators must have a verified ventilation plan.
A verified ventilation plan is a plan that has been demonstrated as 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
MSHA will initiate the plan verification process when:
(a) You submit a new ventilation plan under § 75.370 or you amend a previously approved ventilation plan under § 75.371(f); or
(b) The District Manager requires you to change the ventilation plan after determining that your dust control parameters no longer effectively control the concentration of respirable dust in the working environment of an MMU under the current mining conditions; or
(c) 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.
The District Manager will notify you of the schedule for verification sampling after granting provisional approval of your ventilation plan. Before you receive provisional approval, however, 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.
To comply with this standard, at the time the District Manager notifies you that MSHA will conduct verification sampling you must:
(a) Set your operating conditions so as to mine at or above the VPL and use only the dust control parameters and other measures listed in your plan on the date scheduled for verification sampling;
(b) For each MMU to be sampled, make available records of the amount of material produced each shift during the previous six-month period as prescribed in § 75.370(h);
(c) Provide the additional information described under § 75.371(f); and
(d) Notify the District Manager if you cannot meet the conditions described in paragraph (a) on the scheduled date.
(a) MSHA will sample the environment of:
(1) The designated occupation (DO); roofbolter operators; longwall jack setters; and
(2) Any other occupation designated by the District Manager.
(b) Unless otherwise directed by the District Manager, MSHA will take DO samples by placing the sampling device(s) in the following locations:
(1) Conventional section using cutting machine—on the cutting machine operator or on the cutting machine within 36 inches inby the normal working position;
(2) Conventional section shooting off the solid—on the loading machine operator or on the loading machine within 36 inches inby the normal working position;
(3) Continuous mining section other than auger-type—on the continuous mining machine operator or on the continuous mining machine within 36 inches inby the normal working position;
(4) Continuous mining machine; auger-type—on the jacksetter who works nearest the working face on the return air side of the continuous mining machine or at a location that represents the maximum concentration of dust to which the miner is exposed;
(5) Scoop section using cutting machine—on the cutting machine operator or on the cutting machine within 36 inches inby the normal working position;
(6) Scoop section shooting off the solid—on the coal drill operator or on the coal drill within 36 inches inby the normal working position;
(7) Longwall section—on the miner who works nearest the return air side of the longwall working face or along the working face on the return side within 48 inches of the corner;
(8) Hand loading section with a cutting machine—on the cutting machine operator or on the cutting machine within 36 inches inby the normal working position;
(9) Hand loading section shooting off the solid—on the hand loader exposed to the greatest dust concentration or at a location that represents the maximum concentration of dust to which the miner is exposed; and
(10) Anthracite mine sections—on the hand loader exposed to the greatest dust concentration or at a location that represents the maximum concentration of dust to which the miner is exposed.
MSHA can approve your ventilation plan based on only one shift of sampling, provided all the samples taken on that shift meet the criteria for a verification sample and none of them exceed the critical values for a single shift specified in §§ 70.209 and 70.213. We will sample additional shifts if one verification sample exceeds the specified critical values, or if any of the samples taken do not meet the criteria for a verification sample.
If you do not have 30 shifts of production data to establish a VPL, the VPL will be the minimum production level attained on a shift that was sampled to verify the plan's effectiveness. This production level must be incorporated into the ventilation plan that is ultimately approved by the District Manager.
MSHA will approve your ventilation plan when:
(a) None of the verification samples exceed the following critical values for respirable coal mine dust and quartz dust:
(1) For respirable coal mine dust, the critical value is:
(i) 1.71 mg/m
(ii) 1.85 mg/m
(iii)1.93 mg/m
(iv) 2.0 mg/m
(2) For respirable quartz dust, the critical value is:
(i) 87 “μg/m
(ii) 93 “μg/m
(iii) 97 “μg/m
(iv) 100 “μg/m
(b) You adjust your plan, if necessary, to include all the dust control parameters that were in effect during verification sampling.
If a verification sample exceeds either verification limit, you must:
(a) Immediately take corrective action to lower the concentration of respirable dust in the work environment of the affected occupation or location to a level no greater than the applicable verification limit;
(b) Make approved respiratory equipment available to affected miners following the procedures in § 70.300; and
(c) Within 5 days of receiving results of verification sampling, submit changes in your dust control parameters and any other corrective actions you implemented to the District Manager for review. The District Manager will notify you if your ventilation plan is provisionally approved under § 70.210 (c).
(1) If your ventilation plan is provisionally approved, the District Manager will notify you when MSHA will start verification sampling over again, or continue verification sampling.
(2) If your ventilation plan is not provisionally approved, the District Manager will require you to make additional changes in your plan parameters. Once you have made all required changes to your plan parameters, you will receive provisional approval of your ventilation plan. Then, the District Manager will notify you when MSHA will start verification sampling over again, or continue verification sampling from the point at which it stopped.
If verification samples continue to exceed the verification limit and you believe all feasible engineering and environmental controls are in place, then:
(a) If the ventilation plan being verified is for an MMU that uses a mining system other than longwall mining, MSHA may suggest additional controls for you to implement.
(b) If the MMU employs a longwall mining system, MSHA may suggest additional controls for you to implement; and, you may request in writing that the Administrator for Coal Mine Safety and Health determine whether or not you are using all feasible engineering or environmental controls to reduce concentrations of respirable dust to as low a level as possible; and
(c) If MSHA determines that you are using all feasible engineering or environmental on your longwall, based on its assessment of the suitability of available control measures to your particular MMU, MSHA will notify you that you may use either powered, air-purifying respirators (PAPRs) approved under 42 CFR 84, or verifiable administrative controls on an interim basis to supplement the engineering or environmental controls you have implemented to achieve compliance, until additional feasible engineering or environmental controls become available. If you use these supplements, the DO would be changed from the 060 to the 044 occupation.
In order to use PAPRs to supplement engineering or environmental controls, you must:
(a) Submit a revised ventilation plan to the District Manager within 5 days of receiving notification allowing you to supplement the engineering or environmental controls on your longwall for compliance purposes. Your plan must include feasible engineering or environmental controls capable of maintaining concentrations of respirable dust in the environment of:
(1) The DO (Occ 044—longwall operator or the occupation selected by the District Manager) at or below the verification limits; and
(2) Any miner working downwind of the DO, who is required to wear a PAPR,
(b) Incorporate in your plan a respiratory protection program for the use of PAPRs following the procedures specified in § 72.710. MSHA's District Manager may require you to make modifications to your respiratory protection program before granting provisional approval;
(c) Obtain provisional approval of your ventilation plan from the District Manager;
(d) Have MSHA verify your plan's effectiveness by sampling the environment of the DO (Occ 044—longwall operator) or other occupation directed by the District Manager and those miners working downwind of the DO who are required to wear approved PAPRs on the longwall face following the verification sampling procedures in §§ 70.205 and 70.206;
(e) Maintain and monitor compliance with the revised ventilation plan; and
(f) Continue to look for improvements that you can make and implement feasible solutions when they become available that would maintain the environment of the miners required to wear PAPRs at or below the verification limits.
MSHA will approve your interim ventilation plan when:
(a) None of the verification samples for the DO exceed the critical values for respirable coal mine dust and quartz dust specified in § 70.209;
(b) None of the verification samples for the miners working downwind of the DO, who are required to wear approved PAPRs, exceed the following critical values for respirable coal mine dust and quartz dust:
(1) For respirable coal mine dust, the value is:
(i) 3.54 mg/m
(ii) 3.77 mg/m
(iii)3.89 mg/m
(iv) 4.0 mg/m
(2) For respirable quartz dust, the value is:
(i) 174 μg/m
(ii) 187 μg/m
(iii) 194 μg/m
(iv) 200 μg/m
(c) You adjust your plan, if necessary, to include all the dust control parameters that were in effect during verification sampling.
You may continue to use approved PAPRs for compliance purposes under the following conditions:
(a) You implement and maintain all feasible engineering or environmental controls on each shift;
(b) You implement and maintain the PAPR respiratory protection program as approved by the District Manager;
(c) No MSHA DO sample exceeds the applicable dust standards, and no MSHA sample for any miner working downwind of the DO and required to wear a PAPR exceeds two times the applicable dust standards; and
(d) You continue to look for improvements that you can make and implement feasible solutions when they become available that would maintain the environment of the miners required to wear PAPRs at or below the verification limits.
If an MSHA DO sample exceeds the dust standard you must:
(a) Promptly review your dust control procedures to determine the cause of the high dust concentration levels and take appropriate action to prevent similar occurrences in the future;
(b) Promptly review the continued effectiveness of your approved PAPR respiratory protection program; and
(c) If necessary, make changes to your dust control parameters and submit them to the District Manager for review and approval.
In order to use administrative controls for longwall operations you must:
(a) Submit a revised ventilation plan to the District Manager within 5 days of receiving notification allowing you to supplement the engineering or environmental controls on your longwall for compliance purposes. The plan must include the feasible engineering or environmental controls being used to reduce the concentrations of respirable dust on your longwall to as low a level as possible, the verifiable administrative controls to be implemented on the MMU, and a method for ensuring that the administrative controls are complied with at all times;
(b) Obtain provisional approval of your ventilation plan from the District Manager;
(c) Have MSHA verify your plan's effectiveness by sampling all miners working along the longwall face, including the DO (Occ 044—longwall operator) or other occupation designated by the District Manager;
(d) Maintain and monitor compliance with the revised ventilation plan; and
(e) Continue to look for improvements that you can make and implement feasible solutions when they become available that would maintain the environment of the miners required to work downwind of the DO and whose exposure is being controlled by administrative controls at or below the verification limits.
MSHA will approve your interim ventilation plan and use of administrative controls on your longwall when:
(a) None of the verification samples exceed the critical values for respirable coal mine dust and quartz dust specified in § 70.209; and
(b) Adjust your plan if necessary, to include all the dust control parameters that were in effect during verification sampling.
If an MSHA sample exceeds the dust standard you must:
(a) Promptly review your dust control procedures to determine the cause of the excessive dust concentration(s) and take appropriate action to prevent similar occurrences in the future;
(b) Promptly review the continued effectiveness of the administrative controls in use; and
(c) If necessary, make changes to your dust control parameters and submit them to the District Manager for review and approval.
If you are cited for exceeding the dust standard, you must:
(a) Promptly review your dust control procedures to determine the cause of the excessive dust concentration(s); and
(b) Take corrective action to lower the concentration of respirable dust to comply with the applicable standard and notify the District Manager within 24 hours after implementing the corrective action(s). MSHA will then sample to determine the effectiveness of your abatement actions or require reverification of your ventilation plan under proposed § 70.203. If MSHA samples demonstrate:
(1) Compliance—you must incorporate these corrective actions in your mine ventilation plan. MSHA may re-verify your ventilation plan after determining that your dust control parameters originally approved may be ineffective in controlling the concentrations of respirable dust in the working environment of the MMU under the current mining conditions.
(2) Noncompliance—the District Manager may revoke approval of your mine ventilation plan.
You must post the following information on the mine bulletin board:
(a) All MSHA sample results;
(b) For each MMU, the engineering and environmental controls and other practices in effect on each shift of the verification process, along with the associated values of the dust control parameters measured;
(c) All written notifications from the District Manager regarding any aspect of the plan verification process.
(d) You may remove the posted verification results after the District Manager approves the plan. You must post the results of MSHA respirable dust compliance samples upon receipt for 31 days.
(a) You must report the change in operational status of the mine, MMU, or DA to the MSHA District Office or to any other MSHA office designated by the District Manager. You must report status changes in writing within 3 working days after the status change has occurred.
(b) Each specific operational status is defined as follows:
(1) Underground mine:
(i) Producing—has at least one mechanized mining unit producing material.
(ii) Nonproducing—no material is being produced.
(iii) Abandoned—the work of all miners has been terminated and production activity has ceased.
(2) Mechanized Mining Unit:
(i) Producing—producing material from a working section.
(ii) Nonproducing—temporarily ceased production of material.
(iii) Abandoned—permanently ceased production of material.
(3) Designated Area:
(i) Producing—activity is occurring.
(ii) Nonproducing—activity has ceased.
(iii) Abandoned—the dust generating source has been withdrawn and activity has ceased.
6. The authority citation for part 75 continues to read as follows:
30 U.S.C. 811.
7. Paragraph (h) of § 75.370 of Subpart D is added to read as follows:
(h) The operator must record the amount of material produced by each MMU during each production shift, retain the records for six months, and make the records available to authorized representatives of the Secretary and the miners' representative.
8. Section 75.371 of Subpart D is amended by revising paragraphs (f) and (t) to read as follows:
(f) Section and face ventilation systems used, including drawings illustrating how each system is used; and a description of each different dust suppression system used on equipment on working sections, including any specific work practices used to minimize the dust exposure of individual miners, along with information on the location of the roof bolter(s) during the mining cycle for each continuous miner section, and the cut sequence for each longwall mining section. For plans required to be verified pursuant to § 70.201, the length of each normal production shift, the verification production level (VPL) as defined in § 70.2, and additional provisions for the use of powered, air purifying respirators (PAPRs) or verifiable administrative controls required under § 70.212–215 and § 70.216–218, respectively, must be included for each working section.
(t) The location of each “designated area,” and the respirable dust measures used at the dust generating sources for these locations.
9. The authority citation for part 90 continues to read as follows:
30 U.S.C. 811, 813(h).
10. Subpart A is revised to read as follows:
This part 90 establishes the option of miners who are employed at underground coal mines or at surface work areas of underground coal mines and who have evidence of the development of pneumoconiosis to work in an area of a mine where the average concentration of respirable dust in the mine atmosphere during each shift is continuously maintained at or below 1.0 milligrams per cubic meter of air. The rule sets forth procedures for miners to exercise this option, and establishes the right of miners to retain their regular rate of pay and receive wage increases. The rule also sets forth the operator's obligations. This part 90 is promulgated pursuant to section 101 of the Act and supercedes section 203(b) of the Act.
(a)
(b)
(c)
(d)
(e)
(1) A unit of mining equipment including hand loading equipment used for the production of material; or
(2) A specialized unit which utilizes mining equipment other than specified in § 70.206(c). MSHA assigns each MMU a four digit identification number. The MMU retains the identification number regardless of where the unit relocates within the mine. When two sets of mining equipment are provided in a series of working places and only one production crew is employed at any given time on either set of mining equipment, the two sets of equipment are be identified as a single MMU. When two or more MMUs are simultaneously engaged in the production of material within the same working section, each such MMU is identified separately.
(f)
(g)
(h)
(i)
(j)
(k)
(l)
(m)
(n)
(o)
(p)
(1) Any change in occupation code of a part 90 miner;
(2) Any movement of a part 90 miner to or from a mechanized mining unit; or
(3) Any assignment of a part 90 miner to the same occupation in a different location at a mine.
(q)
(a) Any miner employed at an underground coal mine or at a surface work area of an underground coal mine who, in the judgment of the Secretary of Health and Human Services, has evidence of the development of pneumoconiosis based on a chest X-ray, read and classified in the manner prescribed by the Secretary of Health and Human Services, or based on other medical examinations shall be afforded the option to work in an area of a mine where the average concentration of respirable dust in the mine atmosphere during each shift to which that miner is exposed is continuously maintained at or below 1.0 milligrams per cubic meter of air. Each of these miners shall be notified in writing of eligibility to exercise the option.
(b) Any miner who is a section 203(b) miner on January 31, 1981, shall be a part 90 miner on February 1, 1981, entitled to full rights under this part to retention of pay rate, future actual wage increases, and future work assignment, shift and respirable dust protection.
(c) Any part 90 miner who is transferred to a position at the same or another coal mine shall remain a part 90 miner entitled to full rights under this part at the new work assignment.
(d) The option to work in a low dust area of the mine may be exercised for the first time by any miner employed at an underground coal mine or at a surface work area of an underground coal mine who was eligible for the option under the old section 203(b) program (36 FR 20601, October 27, 1971), or is eligible for the option under this part by signing and dating the Exercise of Option Form and mailing the form to the Chief, Division of Health, Coal Mine Safety and Health, MSHA, 4015 Wilson Boulevard, Arlington, Virginia 22203.
(e) The option to work in a low dust area of the mine may be re-exercised by any miner employed at an underground coal mine or at a surface work area of an underground coal mine who exercised the option under the old section 203(b).
12. Subpart B is revised to read as follows:
After the twentieth calendar day following receipt of notification from MSHA that a part 90 miner is employed at the mine, the operator shall continuously maintain the average concentration of respirable dust in the mine atmosphere during each shift to which the part 90 miner in the active workings of the mine is exposed at or below 1.0 milligrams per cubic meter of air.
When the respirable dust in the mine atmosphere of the active workings to
The respirable dust associated with a part 90 miner contains quartz in the amount of 20%. Therefore, the average concentration of respirable dust in the mine atmosphere associated with that part 90 miner shall be continuously maintained at or below 0.5 milligrams of respirable dust per cubic meter of air (10/20=0.5 mg/m
(a) Whenever a part 90 miner is transferred in order to meet the respirable dust standard in § 90.100 (Respirable dust standard) or § 90.101 (Respirable dust standard when quartz is present), the operator shall transfer the miner to an existing position at the same coal mine on the same shift or shift rotation on which the miner was employed immediately before the transfer. The operator may transfer a part 90 miner to a different coal mine, a newly-created position or a position on a different shift or shift rotation if the miner agrees in writing to the transfer.
(b) On or before the twentieth calendar day following receipt of notification from MSHA that a part 90 miner is employed at the mine, the operator shall give the District Manager written notice of the occupation and, if applicable, the mechanized mining unit to which the part 90 miner will be assigned on the twenty-first calendar day following receipt of the notification from MSHA.
(c) After the twentieth calendar day following receipt of notification from MSHA that a part 90 miner is employed at the mine, the operator shall give the District Manager written notice before any transfer of a part 90 miner. This notice shall include the scheduled date of the transfer.
(a) The operator shall compensate each part 90 miner at not less than the regular rate of pay received by that miner immediately before exercising the option under § 90.3 (part 90 option; notice of eligibility; exercise of option).
(b) Whenever a part 90 miner is transferred, the operator shall compensate the miner at not less than the regular rate of pay received by that miner immediately before the transfer.
(c) The operator shall compensate each miner who is a section 203(b) miner on January 31, 1981, at not less than the regular rate of pay that the miner is required to receive under section 203(b) of the Act immediately before the effective date of this part.
(d) In addition to the compensation required to be paid under paragraphs (a), (b) and (c) of this section, the operator shall pay each part 90 miner the actual wage increases that accrue to the classification to which the miner is assigned.
(e) If a miner is temporarily employed in an occupation other than his or her regular work classification for two months or more before exercising the option under § 90.3 (part 90 option; notice of eligibility; exercise of option), the miner's regular rate of pay for purposes of paragraph (a) and (b) of this section is the higher of the temporary or regular rates of pay. If the temporary assignment is for less than two months, the operator may pay the part 90 miner at his or her regular work classification rate regardless of the temporary wage rate.
(f) If a part 90 miner is transferred, and the Secretary subsequently notifies the miner that notice of the miner's eligibility to exercise the part 90 option was incorrect, the operator shall retain the affected miner in the current position to which the miner is assigned and continue to pay the affected miner the applicable rate of pay provided in paragraphs (a), (b), (c) and (d) of this section, until:
(1) The affected miner and operator agree in writing to a position with pay at not less than the regular rate of pay for that occupation; or
(2) A position is available at the same coal mine in both the same occupation and on the same shift on which the miner was employed immediately before exercising the option under Sec. 90.3 (Part 90 option; notice of eligibility; exercise of option) or under the old section 203(b) program (36 FR 20601, October 27, 1971).
(i) When such a position is available, the operator shall offer the available position in writing to the affected miner with pay at not less than the regular rate of pay for that occupation.
(ii) If the affected miner accepts the available position in writing, the operator shall implement the miner's reassignment upon notice of the miner's acceptance. If the miner does not accept the available position in writing, the miner may be reassigned and protections under Part 90 shall not apply. Failure by the miner to act on the written offer of the available position within 15 days after notice of the offer is received from the operator shall operate as an election not to accept the available position.
(a) A part 90 miner may waive his or her rights and be removed from MSHA's active list of miners who have rights under part 90 by:
(1) Giving written notification to the Chief, Division of Health, Coal Mine Safety and Health, MSHA, that the miner waives all rights under this part;
(2) Applying for and accepting a position in an area of a mine which the miner knows has an average respirable dust concentration exceeding 1.0 milligrams per cubic meter of air or the respirable dust standard established by § 90.101 (Respirable dust standard when quartz is present); or
(3) Refusing to accept another position offered by the operator at the same coal mine that meets the requirements of §§ 90.100, 90.101 and 90.102(a) after MSHA dust sampling shows that the average respirable dust concentration in his or her present position exceeds 1.0 milligrams per cubic meter of air or the respirable dust standard established by § 90.101 (Respirable dust standard when quartz is present).
(b) If rights under part 90 are waived, the miner gives up all rights under part 90 until the miner re-exercises the option in accordance with § 90.3(e) (part 90 option; notice of eligibility; exercise of option).
(c) If rights under part 90 are waived, the miner may re-exercise the option under this part in accordance with § 90.3(e) (part 90 option; notice of eligibility; exercise of option) at any time.
13. Subpart C is revised to read as follows:
(a) The Secretary shall provide the operator with a report of the following data on the MSHA respirable dust samples as soon as practicable:
(1) The mine identification number;
(2) The mechanized mining unit, if any, within the mine from which the samples were taken;
(3) The concentration of respirable dust, expressed in milligrams per cubic meter of air, for each valid sample;
(4) The average concentration of respirable dust, expressed in milligrams
(5) The occupation code;
(6) The reason for voiding any samples; and,
(7) The Social Security Number of the part 90 miner.
(b) Upon receipt, the operator shall provide a copy of this report to the part 90 miner. The operator shall not post the original or a copy of this report on the mine bulletin board.
If there is a change in the status of a part 90 miner (such as entering a terminated, injured or ill status, or returning to work), the operator must report the change in the status of the part 90 miner to the MSHA District Office or to any other MSHA office designated by the District Manager. Status changes shall be reported in writing within 3 working days after the status change has occurred.