Diesel Particulate Matter Exposure of Underground Metal and Nonmetal Mines, 53280-53293 [05-17802]

Download as PDF 53280 Federal Register / Vol. 70, No. 172 / Wednesday, September 7, 2005 / Proposed Rules DEPARTMENT OF LABOR Mine Safety and Health Administration 30 CFR Part 57 RIN 1219–AB29 questions regarding these issues are discussed within the appropriate sections in the preamble. These questions are italicized for ease of the reader. Public hearing dates and locations are discussed in the SUPPLEMENTARY INFORMATION section below. If you wish to make an oral presentation for the record, we ask that you submit your request at least 5 days prior to the hearing dates. Comments and other appropriate data for the record must be received by close of business on October 14, 2005. ADDRESSES: (1) To submit comments, please include RIN: 1219–AB29 in the subject line of the message and send them to us at either of the following addresses. Federal e-Rulemaking portal: Go to https://www.regulations.gov and follow the online instructions for submitting comments. E-mail: zzMSHA-comments@dol.gov. If you are unable to submit comments electronically, please identify them by RIN: 1219–AB29 and send them to us by any of the following methods. Fax: (202) 693–9441. Mail, hand delivery, or courier: MSHA, Office of Standards, Regulations, and Variances, 1100 Wilson Blvd., Rm. 2350, Arlington, VA 22209–3939. (2) We will post all comments on the Internet without change, including any personal information they may contain. You may access the rulemaking docket via the Internet at https://www.msha.gov/ regsinfo.htm or in person at MSHA’s public reading room at 1100 Wilson Blvd., Rm. 2349, Arlington, VA. (3) To receive an e-mail notification when we publish rulemaking documents in the Federal Register, subscribe to our list serve at https:// www.msha.gov/subscriptions/ subscribe.aspx. DATES: Diesel Particulate Matter Exposure of Underground Metal and Nonmetal Mines Mine Safety and Health Administration (MSHA), Labor. ACTION: Proposed rule; notice of public hearings; close of comment period; request for data. AGENCY: SUMMARY: We propose to revise the January 20, 2006 effective date of the existing diesel particulate matter (DPM) final concentration limit of 160 micrograms of total carbon (TC) per cubic meter of air (160TCµg/m3) in the 2001 final rule ‘‘Diesel Particulate Matter Exposure of Underground Metal and Nonmetal Miners,’’ published in the Federal Register on January 19, 2001 (66 FR 5706). We are considering staggered effective dates for implementation of the final DPM limit, phased-in over a multi-year period, primarily based on feasibility issues that have surfaced since promulgation of the 2001 final rule. We also propose to delete the existing provision that restricts newer mines from applying for an extension of time for meeting the final concentration limit. In addition we are seeking specific comments and data on an appropriate conversion factor for the final DPM limit, technological implementation issues, and the costs and benefits of this rule. Finally, in this proposed rule, we are interested in comments on the appropriateness of including in a final rule a provision for medical evaluation of miners required to wear respiratory protection and transfer of miners who have been determined by a medical professional to be unable to wear a respirator. Specific For information contact Rebecca J. Smith, Acting Director of the Office of Standards, Regulations, and Variances, MSHA, 1100 Wilson Blvd., Arlington, Virginia 22209–3939. Ms. Smith can be reached at (202) 693–9440. SUPPLEMENTARY INFORMATION: FOR FURTHER INFORMATION CONTACT: Outline of Preamble This outline will assist the mining community in finding information in this preamble. I. Public Hearings II. Rulemaking Background A. First Partial Settlement Agreement B. Second Partial Settlement Agreement III. Rulemaking History A. Advance Notice of Proposed Rulemaking (ANPRM) on the Interim and Final Concentration Limits B. Notice of Proposed Rulemaking (NPRM) on the Interim Limit C. Final Rule Revising the Interim Concentration Limit IV. Technological Feasibility A. Introduction B. Background C. Remaining Technological Feasibility Issues V. Complexity of Developing an Appropriate Conversion Factor for the Final Concentration Limit VI. Economic Feasibility VII. Section 101(a)(9) of the Mine Act VIII. Section-by-Section Analysis A. Section 57.5060(b) B. Effect of Eliminating § 57.5060(c)(3)(i) IX. Medical Evaluation and Transfer X. Regulatory Impact Analysis A. Executive Order 12866 B. Costs C. Benefits XI. Regulatory Flexibility Act Certification XII. Paperwork Reduction Act XIII. Other Regulatory Considerations XIV. Proposed DPM Rule Text I. Public Hearings We will hold three public hearings on the proposed rule. The public hearings will be begin at 9 a.m., and will be held on the following dates and locations: Date Location September 26, 2005 ................................ September 28, 2005 ................................ September 30, 2005 ................................ Little America Hotel, 500 South Main Street, Salt Lake City, UT 84101 ................ Clarion Hotel Sports Complex, 9103 E. 39th Street, Kansas City, MO 64133 ...... Marriott Louisville Downtown, 280 West Jefferson Street, Louisville, KY 40202 ... If you wish to make an oral presentation for the record, we ask that you submit your request at least 5 days prior to the hearing dates. However, you do not have to make a written request to speak. Any unallotted time will be made available for persons making same-day requests. The hearings will begin with an opening statement from MSHA, VerDate Aug<18>2005 15:24 Sep 06, 2005 Jkt 205001 followed by an opportunity for members of the public to make oral presentations to a panel. Speakers will speak in the order that they sign in. At the discretion of the presiding official, the time allocated to speakers for their presentation may be limited. Speakers and other attendees may also present information to the MSHA panel for inclusion in the rulemaking record. PO 00000 Frm 00002 Fmt 4701 Sfmt 4702 Phone (801) 363–6781 (816) 737–0200 (800) 228–9290 The hearings will be conducted in an informal manner. The hearing panel may ask questions of speakers. Although formal rules of evidence and cross examination will not apply, the presiding official may exercise discretion to ensure the orderly progress of the hearing and may exclude irrelevant or unduly repetitious material and questions. E:\FR\FM\07SEP2.SGM 07SEP2 Federal Register / Vol. 70, No. 172 / Wednesday, September 7, 2005 / Proposed Rules A verbatim transcript of the proceedings will be included in the rulemaking record. Copies of this transcript will be available to the public, and can be viewed at https:// www.msha.gov. We will accept post-hearing written comments and other appropriate data for the record from any interested party, including those not presenting oral statements, through close of business on October 14, 2005. II. Rulemaking Background On January 19, 2001 we published a final rule addressing the health hazards to underground metal and nonmetal miners from exposure to diesel particulate matter (DPM) (66 FR 5706). The rule established new health standards for these miners by requiring, among other things, use of engineering and work practice controls to reduce DPM to prescribed limits. It set an interim and final DPM concentration limit in the underground metal and nonmetal mining environment with staggered effective dates for implementation of the concentration limits. The interim concentration limit of 400TC µg/m3 was to become effective on July 20, 2002. The final concentration limit of 160TC µg/m3 is scheduled to become effective January 20, 2006. In the 2001 final rule, we projected that the mining industry would meet the final concentration limit in their mines through the use of diesel particulate filtration devices, ventilation changes, and the turnover of equipment and engines to less polluting models (66 FR 5713, 5888). Several mining trade associations and individual mine operators challenged the final rule and the United Steelworkers of America (USWA) intervened in the case, which is now pending in the United States Court of Appeals for the District of Columbia Circuit. The parties agreed to resolve their differences through settlement negotiations with us and we delayed the effective date of certain provisions of the standard. A. First Partial Settlement Agreement On July 5, 2001, as a result of an agreement reached in settlement negotiations, we published two notices in the Federal Register. One notice (66 FR 35518) delayed the effective date of § 57.5066(b) related to tagging requirements in the maintenance standard. The second notice (66 FR 35521) proposed a rule to make limited revisions to § 57.5066(b) and added a new paragraph to § 57.5067(b) ‘‘Engines’’ regarding the definition of the term ‘‘introduced.’’ We published VerDate Aug<18>2005 15:24 Sep 06, 2005 Jkt 205001 the final rule on February 27, 2002 (67 FR 9180). B. Second Partial Settlement Agreement Settlement negotiations continued on the remaining unresolved issues in the litigation, and on July 15, 2002, the parties finalized a written agreement (67 FR 47296, 47297). Under the agreement, the interim concentration limit of 400TC µg/m3 became effective on July 20, 2002, without further legal challenge. We afforded mine operators one year to develop and implement good-faith compliance strategies to meet the interim concentration limit, and we agreed to provide compliance assistance during this one-year period. We also agreed to propose rulemaking on several other disputed provisions of the 2001 final rule. The legal challenge to the rule was stayed pending completion of the additional rulemakings. On July 20, 2003, we began full enforcement of the interim concentration limit of 400TC µg/m3. Our enforcement policy was also based on the terms of the second partial settlement agreement and includes the use of elemental carbon (EC) as an analyte to ensure that a citation based on the 400 TC concentration limit is valid and not the result of interferences (67 FR 47298). The policy was discussed with the DPM litigants and stakeholders on July 17, 2003. III. Rulemaking History A. Advance Notice of Proposed Rulemaking (ANPRM) on the Interim and Final Concentration Limits On September 25, 2002, we published an Advance Notice of Proposed Rulemaking (ANPRM) (67 FR 60199). We noted in the ANPRM that the scope of the rulemaking was limited to the terms of the Second Partial Settlement Agreement and posed a series of questions to the mining community related to the 2001 final rule. We also stated our intent to propose a rule to revise the surrogate for the interim and final concentration limits and to propose a DPM control scheme similar to that included in our longstanding hierarchy of controls scheme used in our air quality standards (30 CFR 56/ 57.5001–.5006) for metal and nonmetal mines. In addition, we stated that we would consider technological and economic feasibility for the underground metal and nonmetal mining industry to comply with revised interim and final DPM limits. We determined at that time that some mine operators had begun to implement control technology on their underground diesel-powered PO 00000 Frm 00003 Fmt 4701 Sfmt 4702 53281 equipment. Therefore, we requested relevant information on current experiences with availability of control technology, installation of control technology, effectiveness of control technology to reduce DPM levels, and cost implications of compliance with the 2001 final rule. B. Notice of Proposed Rulemaking (NPRM) on the Interim Limit In response to our publication of the ANPRM, some commenters recommended that we propose separate rulemakings for revising the interim and final concentration limits to give us an opportunity to gather further information to establish a final DPM limit, particularly regarding feasibility. In the subsequent notice of proposed rulemaking (NPRM) published on August 14, 2003 (68 FR 48668), we concurred with these commenters and notified the public in the NPRM that we would propose a separate rulemaking to amend the existing final concentration limit of 160TC µg/m3. We also requested comments on an appropriate final DPM limit and solicited additional information on feasibility. The proposed rule also addressed the interim concentration limit by proposing a comparable PEL of 308 µg/m3 based on the EC surrogate and included a number of other provisions. C. Final Rule Revising the Interim Concentration Limit We published the final rule revising the interim concentration limit on June 6, 2005 (70 FR 32868). This rule changed the interim concentration limit of 400 µg/m3 measured by TC to a comparable PEL of 308 µg/m3 measured by EC. The rule requires our longstanding hierarchy of controls that is used for our other exposure-based health standards at metal and nonmetal mines, but retains the prohibition on rotation of miners for compliance. Furthermore, the rule, among other things, requires us to consider economic as well as technological feasibility in determining if operators qualify for an extension of time in which to meet the final DPM limit, and deletes the requirement for a control plan. Currently, the following provisions of the DPM standard are effective: § 57.5060(a), establishing the interim PEL of 308 micrograms of EC per cubic meter of air which is comparable in effect to 400 micrograms of TC per cubic meter of air; § 57.5060(d), Addressing control requirements; § 57.5060(e), Prohibiting rotation of miners for compliance with the DPM standard; § 57.5061, Compliance determinations; § 57.5065, Fueling practices; § 57.5066, E:\FR\FM\07SEP2.SGM 07SEP2 53282 Federal Register / Vol. 70, No. 172 / Wednesday, September 7, 2005 / Proposed Rules Maintenance standards; § 57.5067, Engines; § 57.5070, Miner training; § 57.5071, Exposure monitoring; and, § 57.5075, Diesel particulate records. IV. Technological Feasibility A. Introduction When we promulgated the 2001 final rule, we determined that control technologies would be available by January 20, 2006 to reduce DPM concentrations to 160TC µg/m3 micrograms in all types of underground metal and nonmetal mines. In the 2001 final rule, we established a new compliance scheme for these mine operators to implement that was distinguishable from that of our other exposure-based health standards by requiring that miners’ exposures be reduced to a full-shift equivalent environmental or concentration limit where miners work or travel. Historically, our metal and nonmetal exposure-based health standards have been based on a miner’s full-shift personal exposure and required that mine operators reduce miners’ exposures to hazardous chemical substances by establishing a hierarchy of controls utilizing feasible engineering and administrative controls supplemented by respiratory protection, if necessary. Since, we were regulating DPM for the first time we needed a tool to help us to determine whether the mining industry was capable of meeting the interim and final concentration limits of the 2001 final rule using a combination of engineering and work practice controls. We also needed a compliance assistance tool to help mine operators with selection of feasible controls from technology unfamiliar to the mining industry. Consequently, we developed the Estimator. The Estimator mathematically calculates the effect of any combination of engineering and ventilation controls on existing DPM concentrations in a given production area of a mine. This model is in the form of a spreadsheet template that permits instant display of outcomes as inputs are altered. Depending on the amount and type of equipment an operator uses, mining companies could use the Estimator to evaluate the effectiveness of these controls prior to purchasing and installing such controls. We encouraged mine operators to use this tool to assist them in making their decisions regarding the appropriate controls for their mines in meeting the 2001 concentration limits. In the preamble to the 2001 final rule, we included data from our studies where we evaluated emissions VerDate Aug<18>2005 15:24 Sep 06, 2005 Jkt 205001 generated by diesel powered equipment in several diverse underground mining operations which included an underground limestone mine, an underground salt mine, and an underground gold mine. In each mine, we concluded that the necessary combination of controls was available to reduce DPM concentrations well below the final concentration limit. Based on these studies, we concluded that engineering and work practice controls were available to reduce DPM concentrations in all underground metal and nonmetal mines to the required limits. We also distributed to the mining community our publication of ‘‘Practical Ways to Control Exposure to Diesel Exhaust in Mining—a Toolbox’’ which addresses various categories of available DPM controls. These categories of controls include use of low emission engines, low sulfur fuel, aftertreatment devices, ventilation, enclosed cabs, engine maintenance, work practices and training, fleet management, and respiratory protective equipment (66 FR 5712–13). Furthermore, we also examined information regarding types of engines and equipment found in underground metal and nonmetal mines along with their various ventilation systems and concluded that the 2001 final rule was technologically feasible for the mining industry (66 FR 5889). We also concluded that the 2001 final rule was economically feasible but recognized the broad impact of the rule on the underground metal and nonmetal sector of the mining industry. We estimated that the annual cost of the 2001 final rule for these mines would be $25.1 million. The cost for an average underground metal and nonmetal mine was projected to be approximately $128,000 annually primarily for investment in equipment to meet the interim and final concentration limits. In reaching our cost estimates, we anticipated that the interim concentration limit would be met primarily with the use of diesel particulate filters (DPFs), environmental cabs, and ventilation; and the final concentration limit would be met with expanded use of DPFs, ventilation, and turnover in equipment to less polluting models (66 FR 5713, 5888). We included a provision in the 2001 final rule to allow an additional two years for mines experiencing difficulty in reducing DPM levels to the final concentration limit due to technological constraints (66 FR 5861). The June 6, 2005, final rule on the interim limit subsequently revised the extension requirement to provide one year, renewable, extensions to comply with the final limit, based on economic or PO 00000 Frm 00004 Fmt 4701 Sfmt 4702 technological infeasibility, but continues to prohibit newer mines from applying for extensions (70 FR 32966). Following promulgation of the 2001 final rule, we agreed to engage in a joint MSHA/industry 31-Mine Study to, among other things, assess the technological and economic feasibility of underground metal and nonmetal mine operators to achieve compliance with the interim and final DPM concentration limits. Feasibility at each of the 31 mines was determined using the Estimator. The analyses were based on the highest DPM sample result obtained at each mine and all major DPM emission sources at each mine plus spare equipment. On January 6, 2003, we issued our final report entitled, ‘‘MSHA’S Report on Data Collected during a Joint MSHA/Industry Study of DPM Levels in Underground Metal and Nonmetal Mines.’’ With regard to feasibility of compliance with both the interim and final concentration limits, we concluded in the study that it may be both technologically and economically feasible for metal and nonmetal underground mines to comply with the 2001 rule. At that time, however, we acknowledged our limited in-mine documentation on implementation of DPM control technology with issues such as retrofitting and regeneration of filters. Consequently, we committed to continue to consult with the National Institute for Occupational Safety and Health, industry and labor representatives on the availability of practical mine worthy filter technology. NIOSH peer reviewed our final report of the 31-Mine Study (70 FR 32870–73). Furthermore, by letter to MSHA dated June 25, 2003, NIOSH stated that: Operators will need to make informed decisions regarding filter selection, retrofitting, engine and equipment deployment, operation, and maintenance, and specifically work through issues such as in-use efficiencies, secondary emissions, engine backpressure, DPF regeneration, DPF reliability and durability. NIOSH is of the opinion that these issues can be solved if the informed decisions mentioned above are made. (70 FR 32923) In the 2005 rulemaking on the interim limit, we revised our approach to reducing DPM levels by establishing our longstanding hierarchy of controls used for regulating our other exposure-based health standards at metal and nonmetal mines. Also, we changed the concentration limit to a permissible exposure limit whereby we measure a miner’s personal exposure. The Estimator became less significant from our perspective in demonstrating feasibility since the 2005 rulemaking E:\FR\FM\07SEP2.SGM 07SEP2 Federal Register / Vol. 70, No. 172 / Wednesday, September 7, 2005 / Proposed Rules record included more extensive evidence on the ability of the mining industry to meet the interim limit in 2005. Specifically, our rulemaking record included: our final report on the 31-Mine Study; NIOSH’s peer review of the 31-Mine Study; results from our baseline sampling at mines covered under the DPM standard; results of our comprehensive compliance assistance work at mining operations with implementation issues affecting feasibility; NIOSH’s conclusions on the performance of the SKC sampler and the availability of technology for control of DPM; NIOSH’s Diesel Emissions Workshops in 2003 in Cincinnati and Salt Lake City; the Filter Selection Guide posted on the MSHA and NIOSH web sites; MSHA’s final report on DPM filter efficiency; NIOSH’s report titled, ‘‘Review of Technology Available to the Underground Mining Industry for Control of Diesel Emissions’; and, the NIOSH Phase I Isozone study titled, ‘‘The Effectiveness of Selected Technologies in Controlling Diesel Emissions in an Underground Mine— Isolated Zone Study at Stillwater Mining Company’s Nye Mine,’’ all of which were developed following promulgation of the 2001 DPM final rule (70 FR 32916). To attain the interim DPM limit, mine operators are required to install, use, and maintain engineering and administrative controls to the extent feasible. When these controls do not reduce a miner’s exposure to the DPM limit, controls are infeasible, or controls do not produce significant reductions in DPM exposures, operators must continue to use all feasible engineering and administrative controls and supplement them with respiratory protection. When respiratory protection is required under the final standard, mine operators must establish a respiratory protection program that meets the specified requirements. At this time, we believe that this compliance approach coupled with the time-frame for complying with the phased-in limits provides mine operators with maximum flexibility in compliance. We believe that this current compliance approach which incorporates the industrial hygiene concept of a hierarchy of controls scheme for implementing DPM controls would result in feasibility of compliance with each of the phased-in limits contained in this proposal. However, we continue to acknowledge that compliance difficulties may be encountered at some mines due to implementation issues and the cost of VerDate Aug<18>2005 15:24 Sep 06, 2005 Jkt 205001 purchasing and installing certain types of controls. 1. MSHA’s 2001 Assumptions Regarding Compliance With the Final Concentration Limit The assumptions that we used in 2001 in support of our cost estimates included: (a) Fifty percent of the fleet will have new engines (these new engines do not impact cost of the rule) * * * Moreover, due to EPA [Environmental Protection Agency] regulations which will limit DPM emissions from engines used in surface construction, surface mining, and over-the-road trucks (the major markets for heavy duty diesel engines), the market for low tech ‘‘dirtier’’ engines will dry up * * * (b) one hundred percent of the production equipment and about fifty percent of the support equipment will be equipped with filters; (c) about thirty percent of all equipment will need to be equipped with environmentally controlled cabs; (d) twenty three percent of the mines would need new ventilation systems (fans and motors); (e) forty percent of the mines will need new motors on these fans; and (f) thirty two percent of the mines will need major ventilation upgrades (66 FR 5889–90). Furthermore, we concluded that it would not be feasible to require this sector, as a whole, to lower DPM concentrations further, or to implement the required controls more swiftly (66 FR 5888). 2. Reasons Why the 2001 Assumptions Are Now Being Questioned. During the 41⁄2 years since the 2001 final rule was promulgated, the mining industry and MSHA have gained considerable experience with the implementation, use, and cost of DPM control technology. Miners’ DPM exposures have also have declined significantly from a mean of 808DPM µg/m3 (646TC µg/m3 µg/m3 equivalent) prior to the implementation of the standard, to a mean of 233TC µg/ m3 based on current enforcement sampling. The industry, however, is encountering economic and technological feasibility issues with DPM controls as they strive to reduce levels below the interim limit. When we established the 2001 final limit, we were expecting some mine operators to encounter difficulties implementing control technology because the rule was technology forcing. We projected that by this time, practical and effective filter technology would be available that could be retrofitted onto most underground diesel powered equipment. However, as a result of our compliance assistance efforts and through our enforcement of the interim limit, we have become aware that this assumption may not be valid. The PO 00000 Frm 00005 Fmt 4701 Sfmt 4702 53283 applications, engineering and related technological implementation issues that we believed would have been easily solved by now are more complex and extensive than previously thought. Although DPF systems have been proven to be highly effective in reducing elemental carbon, mines are currently experiencing problems with selection and implementation of DPF systems for complying with the interim limit. Since the final limit will require mines to install more DPF systems, these selection and implementation problems will extend over a large portion of the mining industry. At this time we believe that solutions to the problems of selection and implementation have not proceeded as quickly as anticipated since promulgation of the 2001 final rule and many mines will not be able to achieve the final limit by January 20, 2006. Some of the implementation and operational difficulties encountered with the controls are discussed in the sections below. We seek additional information regarding technological difficulties and whether they will increase the cost to comply with the final concentration limit above that estimated in the 2001 final rule. We are particularly interested in whether mine operators have attempted to institute DPF systems that are impractical or have failed to work for their mining operations. We wish to know what types and sizes of DPFs have been evaluated, what types of equipment have been fitted with DPFs, what types and horsepower of engines were installed on the equipment, details concerning monitoring of equipment exhaust temperatures prior to specifying a DPF for a given application, whether DPF installations include a provision for backpressure monitoring, DPF maintenance intervals, DPF life, the results of any DPF failure mode analysis, DPM reductions obtained, and any other data related to in-mine experiences with DPFs on underground metal and nonmetal mining equipment. We believe that wider use of alternative fuels and filter technology can make the 160TC µg/m3 final limit feasible if a staggered phase-in approach is adopted. By lowering the exposure limit in intervals over five years beginning in January 2007, market forces should have sufficient time and incentive to adjust to the new standard. Specifically, a reliable alternative fuel distribution system should induce mine operators to adopt this relatively lowcost method to achieve compliance. The development and distribution of alternative fuels is also encouraged by existing tax credits. We believe that regional distribution networks are E:\FR\FM\07SEP2.SGM 07SEP2 53284 Federal Register / Vol. 70, No. 172 / Wednesday, September 7, 2005 / Proposed Rules beginning to emerge. We seek data on alternative fuel distribution systems. Retrofit options for self-cleaning filters should increase as the filter manufacturers become assured of a reliable market for the devices. Use of newer equipment with cleaner engines will also increase as older equipment is retired from service. We anticipate that this staggered approach will provide the needed time to resolve these logistical and operational issues, and consequently, may not increase our 2001 projection of the cost of compliance with the rule. During this phase-in, we will continue to work with the Diesel Partnership (discussed below) and the mining industry to address the DPF selection and implementation problems and identify effective solutions for the diverse metal and nonmetal mining environment. Additionally, we request comments on the percentage of diesel equipment, by mine size, in metal and nonmetal mines that currently have newer, low DPM emitting engines such as EPA Tier I and Tier 2 compliant engines. Our 2001 cost estimates were based, in part, on the assumption that by the effective date of the final limit, 50% of the diesel equipment fleet would have new engines (66 FR 5889). We are interested in whether our 2001 assumption was accurate. If the percentage is lower than originally estimated, it may require the industry to rely even more heavily on filters and other types of controls at added costs. Relying on DPFs to be installed on older, higher DPM emitting engines may also introduce additional implementation issues since DPF manufacturers normally do not recommend adding DPFs to older engines. Although we recognize various types of controls that mine operators could use to reduce miner exposure to DPM, we believe that turnover in equipment to less polluting models and the use of DPFs would be the primary method of achieving compliance with the final DPM limit. We also recognize promising advances in alternative fuel technology since the 2001 final rule was promulgated. These fuels can be extremely effective in reducing DPM emissions. Additionally, the fuels would be in tune with recent U.S. initiatives towards greater energy independence. On October 22, 2004, President Bush signed into law a 50cent-per-gallon tax credit for producers of bio-diesel. He also extended federal tax credits for ethanol through 2007 as part of H.R. 4520, also known as the American Jobs Creation Act of 2004 (Pub. L. 108–357). VerDate Aug<18>2005 15:24 Sep 06, 2005 Jkt 205001 Currently, however, logistical problems exist with the distribution of these fuels to remote mining areas, and the effect of these fuels on power output and operation at high altitude needs to be addressed more fully. Although MSHA, industry, and the Diesel Partnership are actively working to address these concerns, additional time may be needed to find effective solutions for the implementation of DPM controls. B. Background 1. Diversity of Underground Mines Affected By the Final DPM Concentration Limit The metal and nonmetal mining industry has 177 underground mines that use numerous pieces of diesel powered equipment, widely distributed throughout each mining operation. These mines employ an array of mining technologies to produce commodities including metals such as lead, zinc, platinum, gold, silver, etc. Also, there are different types of nonmetal mines that produce stone products such as limestone, dolomite, sandstone, and marble. Other underground nonmetal mines produce clay, potash, trona, soda ash, and salt. Not only do these mines vary in the commodities that they produce, but they also use different mine designs and mining techniques such as room and pillar mining and stope mining. Some of these mines are large, complex multilevel mines, while others are small adit-type mines. Ventilation levels in these mines also vary widely. Many limestone mines have only natural ventilation with variable air movement, whereas trona mines have high ventilation rates to dilute and remove methane gas released in the mining process. There are also deep metal mines with multiple levels that have far less ventilation than that found in underground trona mines. Furthermore, many metal and nonmetal mines are located in remote areas of the country, at high altitudes, or are subject to extremely hot or cold environments. Considering these factors as a whole, we have found that there is no single solution to control technology that would be effective for all metal and nonmetal mines in significantly reducing current DPM levels to or below the final DPM concentration limit of 160TC micrograms. Institute for Occupational Safety and Health (NIOSH), industry trade associations, and organized labor. We are not a member of the Partnership because of our ongoing DPM rulemaking activities. The primary purpose of the Partnership is to identify technologically and economically feasible controls using existing and available technology that can be retrofitted onto existing diesel powered equipment in underground metal and nonmetal mines to reduce diesel particulate matter emissions to, or below, our interim and final limits. The Partnership has been actively involved with NIOSH in its work on diesel particulate control technology including its isolated zone studies at the Stillwater Mine in Montana. NIOSH has published the following reports of its work with the Partnership: ‘‘The Effectiveness of Selected Technologies in Controlling Diesel Emissions in an Underground Mine—Isolated Zone Study at Stillwater Mining Company’s Nye Mine (Phase I Study);’’ ‘‘An Evaluation of the Effects of Diesel Particulate Filter Systems on Air Quality and Personal Exposure of Miners at Stillwater Mining Case Study: Production Zone (Phase II Study);’’ and, ‘‘The Effectiveness of Reformulated Fuels and Aftertreatment Technologies in Controlling Diesel Emissions (Phase III—A Study in an Isolated Zone at Stillwater Mining Company’s Nye Mine August 31–September 11, 2004).’’ NIOSH stated in its conclusion to the Phase III study that: 2. Work of the M/NM Diesel Partnership (the Partnership) This study did not address the important critical path of economic and technical aspects relating to implementation of the studied technologies into underground mines. The successful implementation of control technologies is predicated on addressing issues which are relatively unique to each mine and even to individual applications within a given mine. Most of these technical and operational issues could be investigated through a series of long-term field studies where control technologies would be wisely selected and optimized for the applications, performance of the technologies would be continuously monitored and the effects of the controls on concentrations of diesel pollutants in the mine air would be periodically assessed. The findings of such studies would allow operators to make informed decisions regarding the selection, optimization and implementation of control technologies for its applications and maximize the benefits of using those technologies. It is recommended that these studies be designed and undertaken under the leadership of the Metal/Nonmetal Diesel Partnership. Since promulgation of the January 2001 final rule, we have worked with a Partnership that is composed of representatives from the National On-going NIOSH diesel research related to the Partnership includes a contract that the NIOSH Pittsburgh Research Laboratory issued to Johnson PO 00000 Frm 00006 Fmt 4701 Sfmt 4702 E:\FR\FM\07SEP2.SGM 07SEP2 Federal Register / Vol. 70, No. 172 / Wednesday, September 7, 2005 / Proposed Rules Matthey Catalyst to develop a system to control nitrogen dioxide (NO2) emissions from diesel-powered underground mining vehicles equipped with the Johnson Matthey’s Continuously Regenerating Trap (CRT) system. This system promotes regeneration at lower temperatures and is widely used in urban bus applications. If the results of laboratory evaluations show that a system is suitable for use in underground mining, NIOSH would continue studying this control technology with a long-term field evaluation in an underground mine. C. Remaining Technological Feasibility Issues In January 2001, we concluded that technology existed to sample accurately for DPM with a TC method and to bring DPM levels to the 160 TC level by January 2006 (66 FR at 5889). We further concluded that if any particular mine found unforeseen technological barriers to meeting the January 2006 deadline, it could apply for an extension of up to two additional years to comply with the 160 limit (66 FR at 5889). Our discussion of technological feasibility in support of the interim PEL of 308EC µg/ m3 in the June 6, 2005 final rule concluded that it was technologically feasible to reduce underground miners’ exposures to the interim PEL by using available engineering control technology and various administrative control methods. In fact, our testing at Kennecott Minerals Green’s Creek Mine showed that ceramic diesel particulate filters (DPFs) were capable of reducing diesel exposures by 95%. However, we acknowledged that compliance difficulties may be encountered at some mines due to implementation issues and the cost of purchasing and installing certain types of controls. Specifically, implementation issues may adversely affect the feasibility of using DPFs to reduce exposures despite the results reported in NIOSH’s Phase I Isozone Study. Our experience since January 2001 has raised questions on technological feasibility for the mining industry as a whole, rather than for a small number of individual mines, to meet the 160 TC concentration limit by January 20, 2006. When we conducted our baseline sampling in 2002 and 2003, we found that over 75% of the underground mines covered by the 2001 final rule have levels that would exceed the final concentration limit of 160TC micrograms. Our current enforcement data indicate that approximately 65% of the underground mines covered by the 2001 final rule have levels that would VerDate Aug<18>2005 15:24 Sep 06, 2005 Jkt 205001 exceed the final concentration limit. Although exposures have decreased with implementation of controls and enforcement of the interim concentration limit, we have tentatively concluded that the 160TC microgram final concentration limit presents a significant challenge to a substantial number of underground mine operators and compliance may not be feasible by January 2006. That conclusion is supported by our current enforcement sampling results that indicate that many mining operations have exposures above the 160TC concentration limit, and availability of effective control technology that will reduce exposures to the final limit is speculative at this time. Moreover, comments from industry trade associations and individual mine operators in the post-January 2001 rulemakings recommended that we repeal the 160 limit as technologically infeasible. Organized labor, on the other hand, has recommended that a limit below 160 is technologically feasible. We request comments on whether compliance is technologically feasible by January 2006 and the appropriateness of a multi-year phasein of the final limit. We also request comments and data on when the technology will be feasible. Specific technological implementation issues are discussed in more detail in the following subsections C.1 through C.4. We also request comments on whether compliance difficulties may lead to another problem by requiring a large number of miners to wear respirators until feasible controls are fully implemented. We have never had a standard that resulted in a significant percentage of the workforce being required to wear respiratory protection, and we are concerned about the impact on worker acceptance of the rule and about mine operators’ ability to remain productive. We are interested in public comment on how many miners would need to wear respirators to comply with the 2001 final limit and proposed multiyear phase-in of the final limit, and whether in each case they would need to wear respirators for their entire work shift, whether this amount of respirator usage is practical, and any other comments or observations concerning this issue. 1. Implementation of Available DPFs We continue to project that many mine operators will have to use DPFs to reduce DPM levels to the final concentration limit. The mining industry maintains that while some operators are using DPFs to control miners’ exposures to the interim PEL, it is infeasible for them to further reduce PO 00000 Frm 00007 Fmt 4701 Sfmt 4702 53285 miners’ exposures through expanded use of DPFs. While passive DPF regeneration systems are preferred over active regeneration systems, many pieces of mining equipment do not have duty cycles that will consistently support passive regeneration. Passive regeneration is the process where the exhaust gas temperature produced by the engine is sufficient to burn off the collected DPM on the DPF. Passive regeneration is normally preferred because a DPF can be installed on a machine, and the operator does not have to be concerned with removing the DPF on a routine schedule that may occur at the end of every shift. However, passive regeneration does require the machine operator to monitor the engine’s exhaust gas backpressure. As the DPF loads up with DPM, the inability of the exhaust gas to burn off the DPM allows the backpressure to increase. Increasing the backpressure above the manufacturer’s specifications can cause engine and DPF damage. We request information on the number of currently installed passive regeneration DPF filters. Also, we are interested in the methods used by the industry to match a passive regeneration DPF to a machine. However, we are aware that two identical machines operating in two different mines may not both be able to use passive regeneration. We would be interested in comments about practical experience with these implementation issues. If passive regeneration is infeasible, active regeneration is an alternative. Active regeneration depends on an external heat source for burning off the DPM. Mine operators have informed us that some mining operations cannot utilize active regeneration due to physical size of filters, machine down time, or the cost associated with underground regeneration stations required for DPF regeneration. We request that commenters submit information from the mines that are utilizing active regeneration including data regarding the benefits and the practicability of active regenerating filters. Engine emissions and exhaust flows also affect the size of the DPF that needs to be installed. Both of these factors can affect both passive and active regeneration. If the DPF is undersized for a particular application due to high DPM emissions or high exhaust flows, a passive or active DPF system may not make it through the entire shift before it must be taken out of service for regeneration because of the high backpressure. E:\FR\FM\07SEP2.SGM 07SEP2 53286 Federal Register / Vol. 70, No. 172 / Wednesday, September 7, 2005 / Proposed Rules While some of the mining industry has made improvements by replacing older engines with newer engines in order to reduce DPM emissions, we believe this has occurred mostly for the larger horsepower engines, greater than 150 hp. Smaller engines normally found in the support equipment have not had DPM reductions equivalent to the larger engines. Since we estimated that 50% of the support equipment would probably need DPFs for compliance with the final limit (66 FR 5889–90), the higher DPM emissions from the engines used in support equipment can further complicate the impact on compliance. The mining industry has stated that it needs additional time to further evaluate the proper sizing of DPF systems for both passive and active regeneration. We seek further comment regarding these technological implementation issues as they affect feasibility of compliance with the final concentration limit including the practicality of available DPM control technology. We request that the mining community specifically address issues surrounding off-board regeneration: back pressure build up; frequency of the necessity to clean DPFs; the difficulty of placement of regeneration stations; and information on the extent to which diesel powered equipment accommodates a retrofit of the DPF. 2. Benefits of On-Board Regeneration a. ArvinMeritor System. The ArvinMeritor system, which utilizes active regeneration of the DPF, offers great potential for underground mines in further reducing DPM exposures. The ArvinMeritor system utilizes an onboard fuel burner system to regenerate DPFs. This system actively regenerates the filter media during normal equipment operations by causing the fuel to ignite the burner and thereby increase the exhaust temperature in the filter system. Consequently, this system does not require the host vehicle to travel to a regeneration station to regenerate the DPF. The condition of the DPF is monitored via sensors. While this product was successfully evaluated at Stillwater’s Nye Mine, we have recently learned that the manufacturer has decided to concentrate on working with Original Equipment Manufacturers (OEMs) where they would be selling 50 units or more to one customer rather than selling one or two units per customer. b. Johnson Matthey’s CRT System for DPM reduction (Johnson Matthey). As stated above, passive regeneration works by using the exhaust gas generated by the engine to burn the DPM. Normally, VerDate Aug<18>2005 15:24 Sep 06, 2005 Jkt 205001 DPF manufacturers utilize catalyst technology to lower the temperature needed for successful passive regeneration. By lowering the exhaust gas temperature needed for passive regeneration, a broader range of machines will have the necessary duty cycle to generate the exhaust gas temperature needed to burn the DPM. However, when a platinum coating is used as the catalyst, it can also increase the nitrogen dioxide (NO2) emissions from the engine exhaust. In mines with low ventilation rates, the increased NO2 emissions can also result in increased NO2 exposures to potentially dangerous levels for miners. We discuss this issue in the final rule on the interim PEL (70 FR 32924–26). Therefore, other methods for passive regeneration are being developed to resolve these issues. In 2004, the NIOSH Pittsburgh Research Laboratory issued a contract to Johnson Matthey to develop a system that can regenerate at lower exhaust gas temperatures and control NO2 emissions. The system is based on Johnson Matthey’s CRT system and promotes regeneration at lower temperatures. Such DPFs are widely used in urban bus applications and are capable of passively regenerating DPFs at the temperatures commonly seen in the exhausts of underground mining equipment (above 250 °C for at least 40% of the operation time). The laboratory evaluation of the systems is being executed under NIOSH contract by the Center for Diesel Research (CDR) at the University of Minnesota. The objective is to examine performance and suitability of the systems relative to heavy-duty diesel engines in underground mining applications, with specific focus on the effectiveness of controlling NO2. If the results of laboratory evaluations show that the system is suitable for use in underground applications, NIOSH would continue to study this promising control with a long-term field evaluation in an underground mine environment. We request comments from the mining community regarding the foreseeable utility of these and other new control technologies for reducing DPM levels in underground metal and nonmetal mines. 3. Operators’ Limited Access to Alternative Fuels and Ultra LowSulphur Fuels During our compliance assistance efforts, we observed mines with several applications of alternative fuels, including water emulsion fuels and biodiesel fuels both of which are EPA approved fuels. We subsequently tested these alternative fuels to determine if PO 00000 Frm 00008 Fmt 4701 Sfmt 4702 they could decrease tailpipe DPM emissions. In each application the change to an alternative fuel had a positive impact on reducing engine emissions and miners’ exposures to DPM. In some cases, reductions of 50 to 80+ percent were measured. While we found notable benefits, the use of alternative fuels can also cause equipment operation issues for mine operators. These operational issues have included initial clogging of the fuel filters when bio-diesel is used, reduction of horsepower with the use of water emulsion fuels, and management of proper fueling of the correct fuel into specific machines. While these operational issues could be overcome, each mine has to work through implementation issues on a case-by-case basis. The most common problem with alternative fuels is lack of geographic proximity of most mines to a fuel distributor. Fuel distribution centers tend to be near large cities. As a result, alternative fuels need to be transported to mine sites, in some cases significantly increasing costs. Fuel manufacturers are building distribution centers near mining areas to reduce the transportation costs, but these centers will take some additional time to complete. Limited distribution is also a feasibility issue for metal and nonmetal mine operators who seek to obtain ultra low sulfur fuel. However, as discussed elsewhere in this preamble, the commercial availability of ultra low sulfur fuel will increase during 2006 and beyond when on-highway vehicles in the United States will be required by the EPA to use only this type of diesel fuel. a. Water Emulsion Fuels. Water emulsion fuels, such as PuriNox, are blends of diesel fuels and water. The water is held in suspension with a surfactant. The water in the fuel reduces the engine combustion temperature resulting in reduced NO2 and reduced DPM emissions. However, the added water also reduces the engine’s horsepower. While the per gallon price of the water emulsion fuel is the same as standard fuel, we are aware of increases in engine consumption of these fuels by as much as 15 percent. However, continued increased use in mines is currently limited due to lack of fuel availability in most mining regions. Manufacturers of this fuel must install centralized blender facilities in order to make the fuel more available and economically feasible for use by the metal and nonmetal mining industry. Some fuel system issues have also been observed with some engines using water emulsion fuels. One issue appears E:\FR\FM\07SEP2.SGM 07SEP2 Federal Register / Vol. 70, No. 172 / Wednesday, September 7, 2005 / Proposed Rules to be with the use of very efficient water separators used on engine fuel systems to remove water from the fuel lines. A very efficient water separator will actually remove the water from the emulsion, thus affecting the engine’s performance. An engine manufacturer that has experienced this with its engines has recommended replacing the more efficient water separator with a less efficient one. Another issue identified by some mine operators is that some small machines cannot run, or run poorly, on this fuel. We are not aware of any testing that has been done to prove or disprove this. This may or may not be due to less complex fuel systems that cannot handle a change in fuel properties. We request any information that would help a mine operator determine if certain machines in a fleet cannot run efficiently on this type of fuel. Since water emulsion fuels have been associated with horsepower loss, mines will have to determine through their own in-mine test if their machines can continue to operate efficiently even with the power loss. Some situations where the power loss could affect a machine’s productivity occur at multilevel underground mines at high altitudes. Also, mines that require the use of permissible engines with pre-chamber combustion, such as the metal and nonmetal gassy mines, may need to determine any additional effects on these types of engines. These mines may need additional time to assess the impact of the elevation and grade on power loss. We request comments on the mining industry’s experience with using water emulsion fuels to reduce DPM exposures. b. Bio-Diesel Fuels. While bio-diesel fuels are more readily available than water emulsion fuels, there has not been a consistent supply or standard cost of the fuel. Both costs and demand for these fuels in the mining industry have been related primarily to tax credits available for using the fuel. With current tax credits, bio-diesel can be an attractive fuel alternative for the mining industry. However, we have observed maintenance issues with application of bio-diesel fuels similar to those associated with water emulsion fuels. Particularly, bio-diesel functions as a solvent and cleans the fuel system. This results in increased clogging and replacement of fuel filters. It may take the mining industry some additional time to assess the impact of the increased maintenance on a mining operation. The other issue related to the use of bio-diesel fuel is the percent of soy oil VerDate Aug<18>2005 15:24 Sep 06, 2005 Jkt 205001 in the mixture. While any blend is available, B20 is a 20 percent blend, and B50 is a 50 percent blend, etc., we note that significant DPM reductions are not realized unless the bio-diesel blend exceeds 20 percent. We request comments on the mining industry’s experience with using bio-diesel fuels to reduce DPM exposures. 4. Installation of Environmental Cabs Environmental cabs are a proven means to reduce worker exposure to DPM. While much of the constructiontype equipment used in underground stone mines comes equipped with environmental cabs, the cabs on specialty mining equipment used in underground hard rock mining are less common, particularly in mines with narrow drifts or low seam heights. As mine operators realize the benefits of cabs, more and more pieces of equipment are being purchased or retrofitted with environmental cabs. These cabs provide protection for workers not only from diesel particulate but also from noise and dust. Many mines have begun a retrofit program, but may require additional time to design and retrofit specialty mining equipment with environmental cabs. We request comments on the mining industry’s experience with using environmental cabs to reduce DPM exposures. V. Complexity of Developing an Appropriate Conversion Factor for the Final Concentration Limit The June 6, 2005 rule uses a 1.3 conversion factor to convert the interim PEL of 400TC µg/m3 to 308EC µg/m3, because EC comprises only a fraction of TC. We used a factor of 1.3, to be divided into 400TC µg/m3, to produce a reasonable estimate of TC without interferences. The EC interim limit is based on the median TC to EC (TC/EC) ratio of 1.3 that was observed for valid samples in the 31-Mine Study and agreed to in the second partial DPM settlement agreement (70 FR 32944). Enforcement sample results to date have also shown that for the 400TC µg/m3 interim limit, 1.3 is the most appropriate conversion factor. However, we believe at this time that the 1.3 conversion factor may not be appropriate to convert the final phasedin TC limits to EC because of the variety of DPM controls being adopted by mine operators since the 31-Mine Study. Depending on the types of DPM controls being installed at the mines, a new conversion factor for EC may be needed. Clean engines have more of an impact on reducing OC levels. Alternative fuels, ventilation, and work practices seem to PO 00000 Frm 00009 Fmt 4701 Sfmt 4702 53287 lower EC and TC at similar rates, while DPF and environmental cabs appear to be more effective in reducing EC levels. The actual TC to EC ratio could vary from mine to mine, and even from one section in a mine to another, based on the mix of controls at a mine. We are seeking to maintain the level of protection for miners provided by the final limit promulgated by the 2001 final rule, pursuant to Section 101(a)(9) of the Mine Act. When considering the feasibility of compliance and sampling constraints, we believe that the conversion factor from TC to EC for the phased-in final limits should take into account the OC and EC ratios so that the OC and EC components together would be equivalent to a TC concentration. We are working with NIOSH to develop an appropriate conversion factor for converting the TC limits of this rulemaking to EC limits. Information provided by NIOSH indicated that the ratio of TC to EC in the 31-Mine Study is 1.25 to 1.67 (70 FR 32944). NIOSH’s report on the Phase I study conducted in May, 2003, shows that the EC reduction in the isolated zone with one DPF system was 88% and that two other systems gave greater than 96% EC reductions when the measured concentrations were normalized by ventilation rate. In the final report of the Phase II study, NIOSH indicated that higher EC reductions were observed in the field than were obtained in the laboratory for whole diesel particulate. The results of these studies, as well as other mine studies NIOSH has conducted, help inform us of the EC to TC ratio at different DPM concentrations. Measuring only the EC component ensures that only diesel particulate material is being measured. However, there are no established relationships between the concentration of EC and total DPM under various operating conditions. We welcome comments regarding the types of data we should request from NIOSH to assist us in developing an appropriate conversion factor for converting the TC limits of this proposed rule to EC limits. We will initiate a separate rulemaking to determine what the correct TC to EC conversion factor will be for the phasedin final limits. In the meantime, we are interested in receiving comments on whether the record supports an EC PEL without regard to any conversion factor, the appropriate conversion factor if one is used, and any other scientific approaches for converting the existing TC limit to an appropriate EC limit. However, if a rulemaking to establish a conversion factor is not complete before January 20, 2007, we are considering E:\FR\FM\07SEP2.SGM 07SEP2 53288 Federal Register / Vol. 70, No. 172 / Wednesday, September 7, 2005 / Proposed Rules using the current 1.3 conversion factor that we used to establish the interim DPM PEL of 308 EC micrograms to convert the phased-in final DPM TC limits to EC equivalents. As we did with the interim TC limit pursuant to the July 2002 settlement, we would use the EC equivalents as a check to validate that an overexposure is not the result of interferences. We are interested in receiving comments on this approach to enforcement of the 2007 PEL, assuming the conversion factor rulemaking is not completed before January 20, 2007. VI. Economic Feasibility In January 2001, we estimated that yearly cost of the final rule would be about 0.67% of yearly industry revenue, which was less than the 1% ‘‘screen’’ of costs relative to revenues that we use as a presumptive benchmark of economic feasibility (66 FR 5889). In this rulemaking to consider a phased-in approach to the final concentration limit of 160 TC micrograms, we intend to use the entire rulemaking record supporting the 2001 final rule and the new information gathered during the recent rulemaking to promulgate the new interim PEL. Our data in the rulemaking record established that few underground mines would experience severe economic hardship from enforcement of the interim PEL. Our subsequent enforcement data have confirmed that the interim PEL is economically feasible. In order to gain a more thorough rulemaking record, particularly in light of recent technological developments, we request comments on the economic feasibility of the final concentration limit of 160 TC micrograms and implications of the proposed phase-in approach on the economic feasibility. VII. Section 101(a)(9) of the Mine Act Section 101(a)(9) of the Mine Act provides that: ‘‘No mandatory health or safety standard promulgated under this title shall reduce the protection afforded miners by an existing mandatory health or safety standard.’’ We interpret this provision of the Mine Act to require that all of the health or safety benefits resulting from a new standard be at least equivalent to all of the health or safety benefits resulting from the existing standard when the two sets of benefits are evaluated as a whole. The U.S. Court of Appeals for the D.C. Circuit approved such a ‘‘net effects’’ application of Section 101(a)(9). Int’l Union, UMWA v. Federal Mine Safety and Health Admin., 407 F. 3d 1250, 1256–57 (DC Cir. 2005). We have tentatively concluded at this point that this proposed phase-in period of the effective date of existing VerDate Aug<18>2005 15:24 Sep 06, 2005 Jkt 205001 § 57.5060(b) of the 2001 final rule establishing a final DPM concentration limit of 160TC µg/m3 will not reduce miner protection. We are concerned that the final concentration limit may be infeasible for the mining industry in January 2006. Feasibility issues with respect to operator compliance are discussed above. Also, an additional concern is whether an effective sampling strategy exists to enforce the final TC concentration limits with TC as the surrogate. Evidence in the rulemaking record after January 2001 suggests that, in many cases, there is no practical sampling strategy that would adequately remove organic carbon interferences that occur when TC is used as the surrogate. Furthermore, the DPM settlement agreement does not address appropriate enforcement procedures for the final concentration limit. We also believe at this time that the 1.3 conversion factor used for the final interim limit may not be appropriate for substantially lower limits, such as the final TC concentration limit of 160TC µg/m3. Thus, we have concluded at this time that it is questionable whether the final concentration limit of 160TC µg/m3 would provide any more protection for miners than the 308EC µg/m3 interim limit. We have the burden of proof to confirm that an overexposure to DPM actually occurred and the sample result is not due to interferences. If we were to enforce the final DPM concentration limit of 160TC µg/m3, we would need to validate a TC sample result, which cannot be done without an appropriate conversion factor for EC. We request comments on whether a five-year phase-in period for lowering the final concentration limit to 160TC µg/m3 complies with Section 101(a)(9) of the Mine Act. VIII. Section-by-Section Discussion of the Proposed Rule A. Section 57.5060(b) Section 57.5060(b) in the 2001 rule established a final concentration limit of 160TC µg/m3 to become effective after January 19, 2006. In this rulemaking, we propose to stagger the effective dates for implementation of the final DPM limit, phased-in over a five year period. In a separate rulemaking, we will propose changing the phased-in limits from TC to EC. As previously discussed in Section IV, Technological Feasibility, issues have surfaced since promulgation of the 2001 final rule that indicate the mining industry, taken as a whole, may need additional time to address implementation issues. We are still committed to ensuring that mine PO 00000 Frm 00010 Fmt 4701 Sfmt 4702 operators continue the significant progress they have already demonstrated in reducing miners’ exposures to DPM. As a first step in revising the final concentration limit, we are proposing the interim PEL of 308 micrograms to remain in effect until January 20, 2007, based on feasibility concerns with respect to compliance and sampling strategy discussed above. MSHA is interested in whether the mining community believes at this time that a reduction, after that date, of the PEL equivalent by 50TC µg/m3 each year from 400TC µg/m3, is feasible and will provide additional time for the implementation of controls and development of distribution systems for alternative fuels. We also request information and comments on mining industry current experiences with feasibility of compliance with a limit lower than the current interim PEL of 308 µg/m3 of elemental carbon (EC). The proposed rule would establish the existing interim PEL of 308TC µg/m3 as the new final PEL for one year until January 20, 2007, and impose limits that are reduced by what we will determine in a separate rulemaking to be the equivalent of 50 micrograms of total carbon from 400TC µg/m3 each succeeding year until the final PEL of 160TC µg/m3 is reached in 2011. Consistent with the 2005 final rule on the interim limit, we propose to change the final limit from a concentration limit to a PEL. We request comments on whether five years is the correct timeframe for reducing miners’ exposures to the 160 micrograms of TC as originally established in the 2001 standard and to have been effective in January 2006. Also, we request information on whether the proposed annual 50 microgram reductions of the final DPM limit are appropriate or, in the alternative, should the final rule include an approach such as one or two reductions. We intend that the provisions regarding extensions of time in which to meet the final concentration limit pursuant to existing § 57.5060(c) would apply to the limits established in proposed § 57.5060(b) effective January 20, 2006. If a mine requires additional time to come into compliance with the revised limit of 308 EC for the first year as in proposed § 57.5060(b)(1) or with the final DPM limit established in any other paragraph of proposed § 57.5060(b) due to technological or economic constraints, the operator of the mine could file an application with our District Manager for a special extension. We request your comments on the impact of granting extensions for E:\FR\FM\07SEP2.SGM 07SEP2 Federal Register / Vol. 70, No. 172 / Wednesday, September 7, 2005 / Proposed Rules compliance with exposure limits that are greater than the 160 TC final limit. We intend to cite a violation of the DPM exposure limit only when we have solid evidence that a violation actually occurred. Accordingly, we would continue to determine that an overexposure has occurred when a sample exceeds the interim limit using an appropriate error factor. The appropriate error factor would be slightly different for each of the reduced PELs. Our error factor model accounts for both intra- and inter-laboratory analytical variability and combines that variability with variability in pump flow rate and other sampling and analytic variables. The appropriate error factors will be based on the same statistically sound paired-punch database as used for the existing exposure limit. When developed, they will be further discussed on our Web site at https:// www.msha.gov under, ‘‘Single Source Page for Metal and Nonmetal Diesel Particulate Matter Regulations.’’ B. Effect of Eliminating § 57.5060(c)(3)(i) The 2001 final rule included a requirement at § 57.5060(c)(3)(i) specifying that applications for a oneyear special extension in which to comply with the final DPM concentration limit of 160 micrograms of TC include information adequate for the Secretary to ascertain that dieselpowered equipment was used in the subject mine prior to October 29, 1998. In our 2005 rule addressing the interim limit, we revised the extension provisions, but we retained the October 29, 1998 factor for our District Manager to consider in granting extensions. The basis for limiting special extensions to underground mines that operated diesel-powered equipment prior to October 29, 1998 was that we released our NPRM of our 2001 final rule on that date. We reasoned that some mines in operation prior to that date could experience compliance difficulties relating to such factors as the basic mine design, use of older equipment with high DPM emissions, etc., and that as a result, some of these mines may require additional time to attain compliance with the final DPM limit. Also, we envisioned that mines opened after that date would be using cleaner engines that would greatly benefit them in complying with the 2001 final concentration limit. Now, we believe that our assumptions were incorrect. We now believe that it is unnecessary to limit the application of extensions to mines operating diesel equipment prior to October 29, 1998, because under current § 57.5060(c), it is voluntary as to whether a mine operator applies for a VerDate Aug<18>2005 15:24 Sep 06, 2005 Jkt 205001 special extension. Extensions involve paperwork which result in a document that a mine operator can rely on for one year (renewable) to show our inspectors that we have determined that it is technologically or economically infeasible at this time for that particular mine operator to achieve compliance with the final limit using engineering and administrative controls. If their miners are wearing respirators, they are in compliance and no citation is issued. This is exactly the same test and the same result under § 57.5060(d) at mines without a formal extension. Under the current rule, mine operators must use all feasible engineering and administrative controls to achieve compliance. If we determine that reaching the final limit is infeasible for technological or economic reasons, and over-exposed miners are in respirators, the operator is deemed to be in compliance and no citation is issued. We will periodically check to determine current DPM exposures and the ability of the mine operator to implement new control technology. We request comments on the benefits of current § 57.5060(c)(3)(i), and the effects of deleting the requirement, along with the number of miners that would be affected if § 57.5060(c)(3)(i) were eliminated. We also request comments on whether the elimination of § 57.5060(c)(3)(i) would result in a reduction in the current level of health protection afforded to miners. IX. Medical Evaluation and Transfer We believe that the phase-in approach of this proposed rule for ultimately reducing miners’ exposures to 160 micrograms of total carbon will resolve many of the existing feasibility issues related to effectively implementing more engineering and administrative controls in metal and nonmetal underground mines to enhance miners’ health. Consequently, fewer miners would be required to wear a respirator to supplement feasible engineering and administrative controls. Whereas most mines can feasibly comply with the existing DPM interim PEL of 308 micrograms of elemental carbon, we expect that some miners will continue to have to wear respirators. With each lower limit, more miners may have to wear respirators for longer time periods until controls become feasible. In the event that miners cannot wear a respirator, existing § 57.5060(d) allows for the use of an air purifying respirator, such as those that are integrated into a hardhat. We believe that such respirators are an effective option under the interim PEL for persons who cannot wear a negative-pressure respirator. PO 00000 Frm 00011 Fmt 4701 Sfmt 4702 53289 We are interested in comments from the mining community on whether we should include in the final rule, pursuant to Section 101(a)(7) of the Mine Act, a provision requiring a medical evaluation to determine a miner’s ability to use a respirator before the miner is fit tested or required to work in an area of the mine where respiratory protection must be used under the final limits. In addition, we are seeking comments on whether the final rule should contain a requirement for transfer of a miner to an area of the mine where respiratory protection is not required if a medical professional has determined in the medical evaluation that the miner is unable to wear a respirator for medical reasons. Currently, our standards do not require medical transfer of metal and nonmetal miners. We are interested in whether the public believes that we should amend the existing respiratory protection requirement at § 57.5060(d) by adding new paragraphs (d)(3) and (d)(4) that would address medical evaluation and transfer rights for miners. We particularly want to know if the final rule should include the following language: (3) The mine operator must provide a medical evaluation, at no cost to the miner, to determine the miner’s ability to use a respirator before the miner is fit tested or required to use the respirator to work at the mine. (4) Upon notification from the medical professional that a miner’s medical examination shows evidence that the miner is unable to wear a respirator, the miner must be transferred to work in an existing position in an area of the same mine where respiratory protection is not required. (i) The miner must continue to receive compensation at no less than the regular rate of pay in the classification held by that miner immediately prior to the transfer. (ii) The miner must receive wage increases based upon the new work classification. We also solicit comments from the public as to whether a transfer provision in the final rule should address issues of notification to the District Manager of the health professional’s evaluation and the fact that a miner will be transferred; the appropriate timeframe within which the transfer must be made; whether a record of the medical evaluation conducted for each miner should be maintained along with the correct retention period; medical confidentiality; and any other relevant issues such as costs to mine operators for implementing a rule requiring medical evaluations and transfer of miners. We preliminarily estimate that medical evaluation and transfer requirements, as described above in E:\FR\FM\07SEP2.SGM 07SEP2 Federal Register / Vol. 70, No. 172 / Wednesday, September 7, 2005 / Proposed Rules proposed § 57.5060(d)(3) and (3)(4), would affect about 50 miners annually for evaluation, about 3 miners annually for transfer, and cost about $40,000 annually. X. Regulatory Impact Analysis A. Executive Order 12866 Executive Order 12866 requires regulatory agencies to assess both the costs and benefits of regulations. In making this assessment, we determined that this final rule will not have an annual effect of $100 million or more on the economy, and therefore is not an economically significant regulatory action as defined by § 3(f)(1) of E.O. 12866. C. Benefits In Chapter III of the Regulatory Economic Analysis in support of the January 19, 2001 final rule (2001 REA), we demonstrated that the DPM final rule for M/NM mines will reduce a significant health risk to underground miners. This risk included the potential for illnesses and premature death, as well as the attendant costs of the risk to 1 The following section, discussing benefits of the proposed rule, notes that MSHA’s original estimate, in 2001, of the benefits of the final limit assumed that mean miner exposure to DPM was larger than VerDate Aug<18>2005 15:24 Sep 06, 2005 Jkt 205001 B. Costs In Chapter IV of the Regulatory Economic Analysis in support of the January 19, 2001 final rule (2001 REA), we estimated total yearly costs to underground M/NM mines for the DPM final rule of $25,149,179 (p. 106). Of this amount, $6,612,464 was the discounted incremental yearly cost of compliance with the final limit. The undiscounted incremental yearly cost for compliance with the final limit was estimated as $9,274,325 (p. 58).1 This proposed rule would amend the January 19, 2001 final DPM rule by phasing in the 160TC µg/m3 final limit over a five-year period to address technological feasibility constraints that have arisen. The discounted present value of the cost saving from this fiveyear phase-in period would be $25,512,045, if compliance with the 160TC µg/m3 final limit were technologically feasible in 2006. The annualized value of this cost saving, using a discount rate of 7%, would be $1,785,843. Table X–1 shows these calculations and also shows the breakdown of these cost savings by mine size. During the 41⁄2 years since the 2001 final rule was promulgated, the mining industry and MSHA have gained considerable experience with the implementation, use, and cost of DPM control technology, which could result in cost changes. Therefore, we solicit public comment concerning the cost of compliance, including any changes in costs that may have occurred since the 2001 REA. the miners’ families, to the miners’ employers, and to society at large. We have incorporated into this rulemaking record the previous DPM rulemaking records, including the risk assessment to the January 19, 2001 standard. Benefits of the January 19, 2001 final rule include continued reductions in lung cancers. In the long run, as the mining population turns over, we estimated that a minimum of 8.5 lung cancer deaths will be avoided per year. We noted that this estimate was a lower bound figure that could significantly underestimate the magnitude of the health benefits. For example, the estimate based on the mean value of all the quantitative estimates examined in the January 19, 2001 final rule was 49 lung cancer deaths avoided per year. that observed in subsequent sampling of baseline and current DPM concentrations experienced by underground M/NM miners. To the extent that benefits were accordingly overestimated in 2001, we expect that the 2001 estimates of cost impacts may have been inflated similarly. PO 00000 Frm 00012 Fmt 4701 Sfmt 4702 E:\FR\FM\07SEP2.SGM 07SEP2 EP07SE05.000</GPH> 53290 Federal Register / Vol. 70, No. 172 / Wednesday, September 7, 2005 / Proposed Rules Other benefits noted in the 2001 REA were reductions in the risk of premature death from cardiovascular, cardiopulmonary, or respiratory causes and reductions in the risk of sensory irritation and respiratory symptoms. However, we did not include these health benefits in its estimates because we could not make reliable or precise quantitative estimates of them. Nevertheless, we noted that the expected reductions in the risk of death from cardiovascular, cardiopulmonary, or respiratory causes and the expected reductions in the risk of sensory irritation and respiratory symptoms are likely to be substantial. You are encouraged to submit additional evidence of new scientific data related to the health risk to underground metal and nonmetal miners from exposure to DPM. The 2001 risk assessment used the best available data on DPM exposures at underground M/NM mines to quantify excess lung cancer risk. ‘‘Excess risk’’ refers to the lifetime probability of dying from lung cancer during or after a 45year occupational DPM exposure. This probability is expressed as the expected excess number of lung cancer deaths per thousand miners occupationally exposed to DPM at a specified mean DPM concentration. The excess is calculated relative to baseline, agespecific lung cancer mortality rates taken from standard mortality tables. In order to properly estimate this excess, it is necessary to calculate, at each year of life after occupational exposure begins, the expected number of persons surviving to that age with and without DPM exposure at the specified level. At each age, standard actuarial adjustments must be made in the number of 53291 survivors to account for the risk of dying from causes other than lung cancer. Occupational exposure is assumed to begin at age 20 and to continue, for surviving miners, until retirement at age 65. The accumulation of lifetime excess risk continues after retirement through the age of 85 years. Table X–2, taken from the 2001 risk assessment, shows a range of excess lung cancer estimates at mean exposures equal to the interim and final DPM limits. The eight exposure-response models employed were based on studies ¨ by Saverin et al. (1999), Johnston et al. (1997), and Steenland et al. (1998). Assuming that TC is 80 percent of whole DPM, and that the mean ratio of TC to EC is 1.3, the interim DPM limit of 500 µg/m3 shown in Table X–2 corresponds to the 308 µg/m3 EC surrogate limit adopted under the June 6, 2005 rulemaking. TABLE X–2.—EXCESS LUNG CANCER RISK EXPECTED AT SPECIFIED DPM EXPOSURE LEVELS OVER AN OCCUPATIONAL LIFETIME (EXTRACTED FROM TABLE III–7 OF THE 2001 RISK ASSESSMENT). Excess lung cancer deaths per 1000 occupationally exposed workers † Study and statistical model Final DPM limit 200 µg/ m3 ¨ Saverin et al. (1999) Poisson, full cohort ........................................................................................................................................... Cox, full cohort ................................................................................................................................................. Poisson, subcohort ........................................................................................................................................... Cox, subcohort ................................................................................................................................................. Steenland et al. (1998) 5-year lag, log of cumulative exposure ............................................................................................................ 5-year lag, simple cumulative exposure ........................................................................................................... Johnston et al. (1997) 15-year lag, mine-adjusted ............................................................................................................................... 15-year lag, mine-unadjusted ........................................................................................................................... Interim DPM limit 500 µg/ m3 15 70 93 182 44 280 391 677 67 159 89 620 313 513 724 783 † Assumes 45-year occupational exposure at 1920 hours per year from age 20 to retirement at age 65. Lifetime risk of lung cancer adjusted for competing risk of death from other causes and calculated through age 85. Baseline lung cancer and overall mortality rates from NCHS (1996). As explained in the June 6, 2005 final rule, the mean DPM concentration levels estimated from both the 31-Mine Study (432–492 µg/m3, depending on whether trona mines are included) and the baseline samples (≈320 µg/m3) fall between the interim and final DPM limits shown in Table X–2. All of the exposure-response models shown are monotonic (i.e., increased exposure yields increased excess risk, though not proportionately so). Therefore, using the most current available estimates of mean exposure levels, they all predict excess lung cancer risks somewhere between those shown for the interim and final limits. Thus, despite substantial improvements apparently attained since the 1989–1999 sampling period addressed by the 2001 risk assessment, underground M/NM miners VerDate Aug<18>2005 15:24 Sep 06, 2005 Jkt 205001 are still faced with an unacceptable risk of lung cancer due to their occupational DPM exposures. Another principal conclusion of the 2001 risk assessment was: By reducing DPM concentrations in underground mines, the rule will substantially reduce the risks of material impairment faced by underground miners exposed to DPM at current levels. Although DPM levels have apparently declined since 1889–1999, MSHA expects that further improvements will continue to significantly and substantially reduce the health risks identified for miners. There is clear evidence of DPM’s adverse health effects, not only at pre-2001 levels but also at the generally lower levels currently observed at many PO 00000 Frm 00013 Fmt 4701 Sfmt 4702 underground mines. These effects are material health impairments as specified under § 101(a)(6)(A) of the Mine Act. From the recent enforcement sample results, 135 out of the 183 mines (73.8%) had at least one sample exceeding the final exposure limit. Because the exposure-response relationships shown in Table X–2 are monotonic, MSHA expects that industry-wide implementation of the interim limit will significantly reduce the risk of lung cancer among miners. This proposed rule would amend the January 19, 2001 final DPM rule by phasing in the final limit over a fiveyear period to address technological feasibility constraints that have arisen. By addressing the technological feasibility issues in this way, this proposed rule would contribute to the E:\FR\FM\07SEP2.SGM 07SEP2 Federal Register / Vol. 70, No. 172 / Wednesday, September 7, 2005 / Proposed Rules realization of the benefits mentioned above. XI. Regulatory Flexibility Act Certification The Regulatory Flexibility Act (RFA) requires regulatory agencies to consider a rule’s economic impact on small entities. Under the RFA, we must use the Small Business Act definition of a small business concern in determining a rule’s economic impact unless, after consultation with the SBA Office of Advocacy, and after opportunity for public comment, we establish a definition which is appropriate to our XII. Paperwork Reduction Act There are no paperwork provisions in this proposed rule. XIII. Other Regulatory Considerations A. National Environmental Policy Act of 1969 We have reviewed this proposed rule in accordance with the requirements of the National Environmental Policy Act (NEPA) of 1969 (42 U.S.C. 4321 et seq.), the regulations of the Council on Environmental Quality (40 U.S.C. part 1500), and the Department of Labor’s NEPA procedures (29 CFR part 11). This proposed rule would have no significant impact on air, water, or soil quality; plant or animal life; the use of land; or other aspects of the human environment. As a result of this environmental assessment, we find that the proposed rule would have no significant impact on the human environment. Accordingly, we have not provided an environmental impact statement. We solicit public comment concerning the accuracy and completeness of this environmental assessment. B. The Unfunded Mandates Reform Act of 1995 This proposed rule does not include any Federal mandate that may result in increased expenditures by State, local, or tribal governments, nor would it VerDate Aug<18>2005 15:24 Sep 06, 2005 Jkt 205001 activities and publish that definition in the Federal Register. For the mining industry, SBA defines ‘‘small’’ as having 500 or fewer workers. We have traditionally considered small mines to be those with fewer than 20 workers. To ensure that the rule conforms to the RFA, we analyzed the economic impact on mines with 500 or fewer workers and also on mines with fewer than 20 workers. In Chapter V of the 2001 REA we estimated yearly revenues for these mine sizes. In Table X–1 of this preamble, we estimate the cost savings to mines of various employment sizes. In Table XI–1 of this preamble we combine these numbers and calculate cost savings as a percentage of revenues. Cost savings are 0.25% of revenues for mines with fewer than 20 employees and 0.06% of revenues for mines with 500 or fewer employees. Since both cost savings calculations are less than one percent of revenues, there is no need to conduct an initial regulatory flexibility analysis. We solicit public comment concerning the accuracy of these cost estimates. We certify that the rule will not have a significant economic impact on a substantial number of small entities under either definition. increase private sector expenditures by more than $100 million annually, nor would it significantly or uniquely affect small governments. Accordingly, the Unfunded Mandates Reform Act of 1995 (2 U.S.C. 1501 et seq.) requires no further agency action or analysis. E. Executive Order 12988: Civil Justice Reform C. The Treasury and General Government Appropriations Act of 1999: Assessment of Federal Regulations and Policies on Families This proposed rule would have no affect on family well-being or stability, marital commitment, parental rights or authority, or income or poverty of families and children. Accordingly, Section 654 of the Treasury and General Government Appropriations Act of 1999 (5 U.S.C. 601 note) requires no further agency action, analysis, or assessment. D. Executive Order 12630: Government Actions and Interference With Constitutionally Protected Property Rights This proposed rule would not implement a policy with takings implications. Accordingly, Executive Order 12630, Governmental Actions and Interference with Constitutionally Protected Property Rights, requires no further agency action or analysis. PO 00000 Frm 00014 Fmt 4701 Sfmt 4702 This proposed rule was written to provide a clear legal standard for affected conduct and was carefully reviewed to eliminate drafting errors and ambiguities, so as to minimize litigation and undue burden on the Federal court system. Accordingly, this proposed rule would meet the applicable standards provided in Section 3 of Executive Order 12988, Civil Justice Reform. F. Executive Order 13045: Protection of Children From Environmental Health Risks and Safety Risks This proposed rule would have no adverse impact on children. Accordingly, Executive Order 13045, Protection of Children from Environmental Health Risks and Safety Risks, as amended by Executive Orders 13229 and 13296, requires no further agency action or analysis. G. Executive Order 13132: Federalism This proposed rule would not have ‘‘federalism implications,’’ because it would not ‘‘have substantial direct effects on the States, on the relationship between the national government and the States, or on the distribution of power and responsibilities among the various levels of government.’’ Accordingly, Executive Order 13132, E:\FR\FM\07SEP2.SGM 07SEP2 EP07SE05.001</GPH> 53292 Federal Register / Vol. 70, No. 172 / Wednesday, September 7, 2005 / Proposed Rules Federalism, requires no further agency action or analysis. H. Executive Order 13175: Consultation and Coordination With Indian Tribal Governments This proposed rule would not have ‘‘tribal implications,’’ because it would not ‘‘have substantial direct effects on one or more Indian tribes, on the relationship between the Federal government and Indian tribes, or on the distribution of power and responsibilities between the Federal government and Indian tribes.’’ Accordingly, Executive Order 13175, Consultation and Coordination with Indian Tribal Governments, requires no further agency action or analysis. I. Executive Order 13211: Actions Concerning Regulations That Significantly Affect Energy Supply, Distribution, or Use Regulation of the metal/nonmetal sector of the mining industry has no significant impact on the supply, distribution, or use of energy. This proposed rule is not a ‘‘significant energy action,’’ because it would not be ‘‘likely to have a significant adverse effect on the supply, distribution, or use of energy * * * (including a shortfall in supply, price increases, and increased use of foreign supplies).’’ Accordingly, Executive Order 13211, Actions Concerning Regulations That Significantly Affect Energy Supply, Distribution, or Use, requires no further agency action or analysis. J. Executive Order 13272: Proper Consideration of Small Entities in Agency Rulemaking We have thoroughly reviewed this proposed rule to assess and take VerDate Aug<18>2005 15:24 Sep 06, 2005 Jkt 205001 appropriate account of its potential impact on small businesses, small governmental jurisdictions, and small organizations. As discussed in Section XI of this preamble, we have determined and certified that this proposed rule would not have a significant economic impact on a substantial number of small entities. Accordingly, Executive Order 13272, Proper Consideration of Small Entities in Agency Rulemaking, requires no further agency action or analysis. XIV. Proposed Rule Text List of Subjects in 30 CFR Part 57 Diesel particulate matter, Metal and nonmetal, Mine safety and health, Underground miners. Dated: September 1, 2005. David G. Dye, Deputy Assistant Secretary of Labor for Mine Safety and Health. For reasons set forth in the preamble, we propose to amend Chapter 1 of Title 30 as follows: PART —57 [AMENDED] 1. The authority citation for part 57 reads follows: Authority: 30 U.S.C. 811 2. Section 57.5060 is amended by revising paragraph (b) and removing paragraph (c)(3)(i) to read as follows: § 57.5060 Limit on exposure to diesel particulate matter. * * * * * (b)(1) Effective January 20, 2006, a miner’s personal exposure to diesel particulate matter (DPM) in an underground mine must not exceed an average eight-hour equivalent full shift airborne concentration of 308 PO 00000 Frm 00015 Fmt 4701 Sfmt 4702 53293 micrograms of elemental carbon per cubic meter of air (308EC µg/m3). (2) Effective January 20, 2007, a miner’s personal exposure to diesel particulate matter (DPM) in an underground mine must not exceed an average eight-hour equivalent full shift airborne concentration of 350 micrograms of total carbon per cubic meter of air (350TC µg/m3). (3) Effective January 20, 2008, a miner’s personal exposure to diesel particulate matter (DPM) in an underground mine must not exceed an average eight-hour equivalent full shift airborne concentration of 300 micrograms of total carbon per cubic meter of air (300TC µg/m3). (4) Effective January 20, 2009, a miner’s personal exposure to diesel particulate matter (DPM) in an underground mine must not exceed an average eight-hour equivalent full shift airborne concentration of 250 micrograms of total carbon per cubic meter of air (250TC µg/m3). (5) Effective January 20, 2010, a miner’s personal exposure to diesel particulate matter (DPM) in an underground mine must not exceed an average eight-hour equivalent full shift airborne concentration of 200 micrograms of total carbon per cubic meter of air (200TC µg/m3). (6) Effective January 20, 2011, a miner’s personal exposure to diesel particulate matter (DPM) in an underground mine must not exceed an average eight-hour equivalent full shift airborne concentration of 160 micrograms of total carbon per cubic meter of air (160TC µg/m3). * * * * * [FR Doc. 05–17802 Filed 9–6–05; 8:45 am] BILLING CODE 4510–43–P E:\FR\FM\07SEP2.SGM 07SEP2

Agencies

[Federal Register Volume 70, Number 172 (Wednesday, September 7, 2005)]
[Proposed Rules]
[Pages 53280-53293]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 05-17802]



[[Page 53279]]

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Part III





Department of Labor





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Mine Safety and Health Administration



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30 CFR Part 57



Diesel Particulate Matter Exposure of Underground Metal and Nonmetal 
Mines; Proposed Rule

Federal Register / Vol. 70, No. 172 / Wednesday, September 7, 2005 / 
Proposed Rules

[[Page 53280]]


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DEPARTMENT OF LABOR

Mine Safety and Health Administration

30 CFR Part 57

RIN 1219-AB29


Diesel Particulate Matter Exposure of Underground Metal and 
Nonmetal Mines

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

ACTION: Proposed rule; notice of public hearings; close of comment 
period; request for data.

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SUMMARY: We propose to revise the January 20, 2006 effective date of 
the existing diesel particulate matter (DPM) final concentration limit 
of 160 micrograms of total carbon (TC) per cubic meter of air 
(160TC[mu]g/m3) in the 2001 final rule ``Diesel 
Particulate Matter Exposure of Underground Metal and Nonmetal Miners,'' 
published in the Federal Register on January 19, 2001 (66 FR 5706). We 
are considering staggered effective dates for implementation of the 
final DPM limit, phased-in over a multi-year period, primarily based on 
feasibility issues that have surfaced since promulgation of the 2001 
final rule. We also propose to delete the existing provision that 
restricts newer mines from applying for an extension of time for 
meeting the final concentration limit. In addition we are seeking 
specific comments and data on an appropriate conversion factor for the 
final DPM limit, technological implementation issues, and the costs and 
benefits of this rule. Finally, in this proposed rule, we are 
interested in comments on the appropriateness of including in a final 
rule a provision for medical evaluation of miners required to wear 
respiratory protection and transfer of miners who have been determined 
by a medical professional to be unable to wear a respirator. Specific 
questions regarding these issues are discussed within the appropriate 
sections in the preamble. These questions are italicized for ease of 
the reader.

DATES: Public hearing dates and locations are discussed in the 
SUPPLEMENTARY INFORMATION section below. If you wish to make an oral 
presentation for the record, we ask that you submit your request at 
least 5 days prior to the hearing dates. Comments and other appropriate 
data for the record must be received by close of business on October 
14, 2005.

ADDRESSES: (1) To submit comments, please include RIN: 1219-AB29 in the 
subject line of the message and send them to us at either of the 
following addresses.
    Federal e-Rulemaking portal: Go to https://www.regulations.gov and 
follow the online instructions for submitting comments.
    E-mail: zzMSHA-comments@dol.gov. If you are unable to submit 
comments electronically, please identify them by RIN: 1219-AB29 and 
send them to us by any of the following methods.
    Fax: (202) 693-9441.
    Mail, hand delivery, or courier: MSHA, Office of Standards, 
Regulations, and Variances, 1100 Wilson Blvd., Rm. 2350, Arlington, VA 
22209-3939.
    (2) We will post all comments on the Internet without change, 
including any personal information they may contain. You may access the 
rulemaking docket via the Internet at https://www.msha.gov/regsinfo.htm 
or in person at MSHA's public reading room at 1100 Wilson Blvd., Rm. 
2349, Arlington, VA.
    (3) To receive an e-mail notification when we publish rulemaking 
documents in the Federal Register, subscribe to our list serve at 
https://www.msha.gov/subscriptions/subscribe.aspx.

FOR FURTHER INFORMATION CONTACT: For information contact Rebecca J. 
Smith, Acting Director of the Office of Standards, Regulations, and 
Variances, MSHA, 1100 Wilson Blvd., Arlington, Virginia 22209-3939. Ms. 
Smith can be reached at (202) 693-9440.

SUPPLEMENTARY INFORMATION:

Outline of Preamble

    This outline will assist the mining community in finding 
information in this preamble.

I. Public Hearings
II. Rulemaking Background
    A. First Partial Settlement Agreement
    B. Second Partial Settlement Agreement
III. Rulemaking History
    A. Advance Notice of Proposed Rulemaking (ANPRM) on the Interim 
and Final Concentration Limits
    B. Notice of Proposed Rulemaking (NPRM) on the Interim Limit
    C. Final Rule Revising the Interim Concentration Limit
IV. Technological Feasibility
    A. Introduction
    B. Background
    C. Remaining Technological Feasibility Issues
V. Complexity of Developing an Appropriate Conversion Factor for the 
Final Concentration Limit
VI. Economic Feasibility
VII. Section 101(a)(9) of the Mine Act
VIII. Section-by-Section Analysis
    A. Section 57.5060(b)
    B. Effect of Eliminating Sec.  57.5060(c)(3)(i)
IX. Medical Evaluation and Transfer
X. Regulatory Impact Analysis
    A. Executive Order 12866
    B. Costs
    C. Benefits
XI. Regulatory Flexibility Act Certification
XII. Paperwork Reduction Act
XIII. Other Regulatory Considerations
XIV. Proposed DPM Rule Text

I. Public Hearings

    We will hold three public hearings on the proposed rule. The public 
hearings will be begin at 9 a.m., and will be held on the following 
dates and locations:

------------------------------------------------------------------------
             Date                      Location              Phone
------------------------------------------------------------------------
September 26, 2005............  Little America Hotel,     (801) 363-6781
                                 500 South Main
                                 Street, Salt Lake
                                 City, UT 84101.
September 28, 2005............  Clarion Hotel Sports      (816) 737-0200
                                 Complex, 9103 E.
                                 39th Street, Kansas
                                 City, MO 64133.
September 30, 2005............  Marriott Louisville       (800) 228-9290
                                 Downtown, 280 West
                                 Jefferson Street,
                                 Louisville, KY 40202.
------------------------------------------------------------------------

    If you wish to make an oral presentation for the record, we ask 
that you submit your request at least 5 days prior to the hearing 
dates. However, you do not have to make a written request to speak. Any 
unallotted time will be made available for persons making same-day 
requests.
    The hearings will begin with an opening statement from MSHA, 
followed by an opportunity for members of the public to make oral 
presentations to a panel. Speakers will speak in the order that they 
sign in. At the discretion of the presiding official, the time 
allocated to speakers for their presentation may be limited. Speakers 
and other attendees may also present information to the MSHA panel for 
inclusion in the rulemaking record.
    The hearings will be conducted in an informal manner. The hearing 
panel may ask questions of speakers. Although formal rules of evidence 
and cross examination will not apply, the presiding official may 
exercise discretion to ensure the orderly progress of the hearing and 
may exclude irrelevant or unduly repetitious material and questions.

[[Page 53281]]

    A verbatim transcript of the proceedings will be included in the 
rulemaking record. Copies of this transcript will be available to the 
public, and can be viewed at https://www.msha.gov.
    We will accept post-hearing written comments and other appropriate 
data for the record from any interested party, including those not 
presenting oral statements, through close of business on October 14, 
2005.

II. Rulemaking Background

    On January 19, 2001 we published a final rule addressing the health 
hazards to underground metal and nonmetal miners from exposure to 
diesel particulate matter (DPM) (66 FR 5706). The rule established new 
health standards for these miners by requiring, among other things, use 
of engineering and work practice controls to reduce DPM to prescribed 
limits. It set an interim and final DPM concentration limit in the 
underground metal and nonmetal mining environment with staggered 
effective dates for implementation of the concentration limits. The 
interim concentration limit of 400TC [mu]g/m3 was 
to become effective on July 20, 2002. The final concentration limit of 
160TC [mu]g/m3 is scheduled to become effective 
January 20, 2006. In the 2001 final rule, we projected that the mining 
industry would meet the final concentration limit in their mines 
through the use of diesel particulate filtration devices, ventilation 
changes, and the turnover of equipment and engines to less polluting 
models (66 FR 5713, 5888).
    Several mining trade associations and individual mine operators 
challenged the final rule and the United Steelworkers of America (USWA) 
intervened in the case, which is now pending in the United States Court 
of Appeals for the District of Columbia Circuit. The parties agreed to 
resolve their differences through settlement negotiations with us and 
we delayed the effective date of certain provisions of the standard.

A. First Partial Settlement Agreement

    On July 5, 2001, as a result of an agreement reached in settlement 
negotiations, we published two notices in the Federal Register. One 
notice (66 FR 35518) delayed the effective date of Sec.  57.5066(b) 
related to tagging requirements in the maintenance standard. The second 
notice (66 FR 35521) proposed a rule to make limited revisions to Sec.  
57.5066(b) and added a new paragraph to Sec.  57.5067(b) ``Engines'' 
regarding the definition of the term ``introduced.'' We published the 
final rule on February 27, 2002 (67 FR 9180).

B. Second Partial Settlement Agreement

    Settlement negotiations continued on the remaining unresolved 
issues in the litigation, and on July 15, 2002, the parties finalized a 
written agreement (67 FR 47296, 47297). Under the agreement, the 
interim concentration limit of 400TC [mu]g/m3 
became effective on July 20, 2002, without further legal challenge. We 
afforded mine operators one year to develop and implement good-faith 
compliance strategies to meet the interim concentration limit, and we 
agreed to provide compliance assistance during this one-year period. We 
also agreed to propose rulemaking on several other disputed provisions 
of the 2001 final rule. The legal challenge to the rule was stayed 
pending completion of the additional rulemakings.
    On July 20, 2003, we began full enforcement of the interim 
concentration limit of 400TC [mu]g/m3. Our 
enforcement policy was also based on the terms of the second partial 
settlement agreement and includes the use of elemental carbon (EC) as 
an analyte to ensure that a citation based on the 400 TC concentration 
limit is valid and not the result of interferences (67 FR 47298). The 
policy was discussed with the DPM litigants and stakeholders on July 
17, 2003.

III. Rulemaking History

A. Advance Notice of Proposed Rulemaking (ANPRM) on the Interim and 
Final Concentration Limits

    On September 25, 2002, we published an Advance Notice of Proposed 
Rulemaking (ANPRM) (67 FR 60199). We noted in the ANPRM that the scope 
of the rulemaking was limited to the terms of the Second Partial 
Settlement Agreement and posed a series of questions to the mining 
community related to the 2001 final rule. We also stated our intent to 
propose a rule to revise the surrogate for the interim and final 
concentration limits and to propose a DPM control scheme similar to 
that included in our longstanding hierarchy of controls scheme used in 
our air quality standards (30 CFR 56/57.5001-.5006) for metal and 
nonmetal mines. In addition, we stated that we would consider 
technological and economic feasibility for the underground metal and 
nonmetal mining industry to comply with revised interim and final DPM 
limits. We determined at that time that some mine operators had begun 
to implement control technology on their underground diesel-powered 
equipment. Therefore, we requested relevant information on current 
experiences with availability of control technology, installation of 
control technology, effectiveness of control technology to reduce DPM 
levels, and cost implications of compliance with the 2001 final rule.

B. Notice of Proposed Rulemaking (NPRM) on the Interim Limit

    In response to our publication of the ANPRM, some commenters 
recommended that we propose separate rulemakings for revising the 
interim and final concentration limits to give us an opportunity to 
gather further information to establish a final DPM limit, particularly 
regarding feasibility. In the subsequent notice of proposed rulemaking 
(NPRM) published on August 14, 2003 (68 FR 48668), we concurred with 
these commenters and notified the public in the NPRM that we would 
propose a separate rulemaking to amend the existing final concentration 
limit of 160TC [mu]g/m3. We also requested 
comments on an appropriate final DPM limit and solicited additional 
information on feasibility. The proposed rule also addressed the 
interim concentration limit by proposing a comparable PEL of 308 [mu]g/
m3 based on the EC surrogate and included a number of other 
provisions.

C. Final Rule Revising the Interim Concentration Limit

    We published the final rule revising the interim concentration 
limit on June 6, 2005 (70 FR 32868). This rule changed the interim 
concentration limit of 400 [mu]g/m\3\ measured by TC to a comparable 
PEL of 308 [mu]g/m\3\ measured by EC. The rule requires our 
longstanding hierarchy of controls that is used for our other exposure-
based health standards at metal and nonmetal mines, but retains the 
prohibition on rotation of miners for compliance. Furthermore, the 
rule, among other things, requires us to consider economic as well as 
technological feasibility in determining if operators qualify for an 
extension of time in which to meet the final DPM limit, and deletes the 
requirement for a control plan.
    Currently, the following provisions of the DPM standard are 
effective: Sec.  57.5060(a), establishing the interim PEL of 308 
micrograms of EC per cubic meter of air which is comparable in effect 
to 400 micrograms of TC per cubic meter of air; Sec.  57.5060(d), 
Addressing control requirements; Sec.  57.5060(e), Prohibiting rotation 
of miners for compliance with the DPM standard; Sec.  57.5061, 
Compliance determinations; Sec.  57.5065, Fueling practices; Sec.  
57.5066,

[[Page 53282]]

Maintenance standards; Sec.  57.5067, Engines; Sec.  57.5070, Miner 
training; Sec.  57.5071, Exposure monitoring; and, Sec.  57.5075, 
Diesel particulate records.

IV. Technological Feasibility

A. Introduction

    When we promulgated the 2001 final rule, we determined that control 
technologies would be available by January 20, 2006 to reduce DPM 
concentrations to 160TC [mu]g/m\3\ micrograms in all types 
of underground metal and nonmetal mines. In the 2001 final rule, we 
established a new compliance scheme for these mine operators to 
implement that was distinguishable from that of our other exposure-
based health standards by requiring that miners' exposures be reduced 
to a full-shift equivalent environmental or concentration limit where 
miners work or travel. Historically, our metal and nonmetal exposure-
based health standards have been based on a miner's full-shift personal 
exposure and required that mine operators reduce miners' exposures to 
hazardous chemical substances by establishing a hierarchy of controls 
utilizing feasible engineering and administrative controls supplemented 
by respiratory protection, if necessary. Since, we were regulating DPM 
for the first time we needed a tool to help us to determine whether the 
mining industry was capable of meeting the interim and final 
concentration limits of the 2001 final rule using a combination of 
engineering and work practice controls. We also needed a compliance 
assistance tool to help mine operators with selection of feasible 
controls from technology unfamiliar to the mining industry. 
Consequently, we developed the Estimator.
    The Estimator mathematically calculates the effect of any 
combination of engineering and ventilation controls on existing DPM 
concentrations in a given production area of a mine. This model is in 
the form of a spreadsheet template that permits instant display of 
outcomes as inputs are altered. Depending on the amount and type of 
equipment an operator uses, mining companies could use the Estimator to 
evaluate the effectiveness of these controls prior to purchasing and 
installing such controls. We encouraged mine operators to use this tool 
to assist them in making their decisions regarding the appropriate 
controls for their mines in meeting the 2001 concentration limits.
    In the preamble to the 2001 final rule, we included data from our 
studies where we evaluated emissions generated by diesel powered 
equipment in several diverse underground mining operations which 
included an underground limestone mine, an underground salt mine, and 
an underground gold mine. In each mine, we concluded that the necessary 
combination of controls was available to reduce DPM concentrations well 
below the final concentration limit. Based on these studies, we 
concluded that engineering and work practice controls were available to 
reduce DPM concentrations in all underground metal and nonmetal mines 
to the required limits. We also distributed to the mining community our 
publication of ``Practical Ways to Control Exposure to Diesel Exhaust 
in Mining--a Toolbox'' which addresses various categories of available 
DPM controls. These categories of controls include use of low emission 
engines, low sulfur fuel, aftertreatment devices, ventilation, enclosed 
cabs, engine maintenance, work practices and training, fleet 
management, and respiratory protective equipment (66 FR 5712-13). 
Furthermore, we also examined information regarding types of engines 
and equipment found in underground metal and nonmetal mines along with 
their various ventilation systems and concluded that the 2001 final 
rule was technologically feasible for the mining industry (66 FR 5889).
    We also concluded that the 2001 final rule was economically 
feasible but recognized the broad impact of the rule on the underground 
metal and nonmetal sector of the mining industry. We estimated that the 
annual cost of the 2001 final rule for these mines would be $25.1 
million. The cost for an average underground metal and nonmetal mine 
was projected to be approximately $128,000 annually primarily for 
investment in equipment to meet the interim and final concentration 
limits. In reaching our cost estimates, we anticipated that the interim 
concentration limit would be met primarily with the use of diesel 
particulate filters (DPFs), environmental cabs, and ventilation; and 
the final concentration limit would be met with expanded use of DPFs, 
ventilation, and turnover in equipment to less polluting models (66 FR 
5713, 5888).
    We included a provision in the 2001 final rule to allow an 
additional two years for mines experiencing difficulty in reducing DPM 
levels to the final concentration limit due to technological 
constraints (66 FR 5861). The June 6, 2005, final rule on the interim 
limit subsequently revised the extension requirement to provide one 
year, renewable, extensions to comply with the final limit, based on 
economic or technological infeasibility, but continues to prohibit 
newer mines from applying for extensions (70 FR 32966).
    Following promulgation of the 2001 final rule, we agreed to engage 
in a joint MSHA/industry 31-Mine Study to, among other things, assess 
the technological and economic feasibility of underground metal and 
nonmetal mine operators to achieve compliance with the interim and 
final DPM concentration limits. Feasibility at each of the 31 mines was 
determined using the Estimator. The analyses were based on the highest 
DPM sample result obtained at each mine and all major DPM emission 
sources at each mine plus spare equipment. On January 6, 2003, we 
issued our final report entitled, ``MSHA'S Report on Data Collected 
during a Joint MSHA/Industry Study of DPM Levels in Underground Metal 
and Nonmetal Mines.'' With regard to feasibility of compliance with 
both the interim and final concentration limits, we concluded in the 
study that it may be both technologically and economically feasible for 
metal and nonmetal underground mines to comply with the 2001 rule. At 
that time, however, we acknowledged our limited in-mine documentation 
on implementation of DPM control technology with issues such as 
retrofitting and regeneration of filters. Consequently, we committed to 
continue to consult with the National Institute for Occupational Safety 
and Health, industry and labor representatives on the availability of 
practical mine worthy filter technology. NIOSH peer reviewed our final 
report of the 31-Mine Study (70 FR 32870-73).
    Furthermore, by letter to MSHA dated June 25, 2003, NIOSH stated 
that:

    Operators will need to make informed decisions regarding filter 
selection, retrofitting, engine and equipment deployment, operation, 
and maintenance, and specifically work through issues such as in-use 
efficiencies, secondary emissions, engine backpressure, DPF 
regeneration, DPF reliability and durability. NIOSH is of the 
opinion that these issues can be solved if the informed decisions 
mentioned above are made. (70 FR 32923)

    In the 2005 rulemaking on the interim limit, we revised our 
approach to reducing DPM levels by establishing our longstanding 
hierarchy of controls used for regulating our other exposure-based 
health standards at metal and nonmetal mines. Also, we changed the 
concentration limit to a permissible exposure limit whereby we measure 
a miner's personal exposure. The Estimator became less significant from 
our perspective in demonstrating feasibility since the 2005 rulemaking

[[Page 53283]]

record included more extensive evidence on the ability of the mining 
industry to meet the interim limit in 2005. Specifically, our 
rulemaking record included: our final report on the 31-Mine Study; 
NIOSH's peer review of the 31-Mine Study; results from our baseline 
sampling at mines covered under the DPM standard; results of our 
comprehensive compliance assistance work at mining operations with 
implementation issues affecting feasibility; NIOSH's conclusions on the 
performance of the SKC sampler and the availability of technology for 
control of DPM; NIOSH's Diesel Emissions Workshops in 2003 in 
Cincinnati and Salt Lake City; the Filter Selection Guide posted on the 
MSHA and NIOSH web sites; MSHA's final report on DPM filter efficiency; 
NIOSH's report titled, ``Review of Technology Available to the 
Underground Mining Industry for Control of Diesel Emissions'; and, the 
NIOSH Phase I Isozone study titled, ``The Effectiveness of Selected 
Technologies in Controlling Diesel Emissions in an Underground Mine--
Isolated Zone Study at Stillwater Mining Company's Nye Mine,'' all of 
which were developed following promulgation of the 2001 DPM final rule 
(70 FR 32916).
    To attain the interim DPM limit, mine operators are required to 
install, use, and maintain engineering and administrative controls to 
the extent feasible. When these controls do not reduce a miner's 
exposure to the DPM limit, controls are infeasible, or controls do not 
produce significant reductions in DPM exposures, operators must 
continue to use all feasible engineering and administrative controls 
and supplement them with respiratory protection. When respiratory 
protection is required under the final standard, mine operators must 
establish a respiratory protection program that meets the specified 
requirements. At this time, we believe that this compliance approach 
coupled with the time-frame for complying with the phased-in limits 
provides mine operators with maximum flexibility in compliance. We 
believe that this current compliance approach which incorporates the 
industrial hygiene concept of a hierarchy of controls scheme for 
implementing DPM controls would result in feasibility of compliance 
with each of the phased-in limits contained in this proposal. However, 
we continue to acknowledge that compliance difficulties may be 
encountered at some mines due to implementation issues and the cost of 
purchasing and installing certain types of controls.
1. MSHA's 2001 Assumptions Regarding Compliance With the Final 
Concentration Limit
    The assumptions that we used in 2001 in support of our cost 
estimates included:

    (a) Fifty percent of the fleet will have new engines (these new 
engines do not impact cost of the rule) * * * Moreover, due to EPA 
[Environmental Protection Agency] regulations which will limit DPM 
emissions from engines used in surface construction, surface mining, 
and over-the-road trucks (the major markets for heavy duty diesel 
engines), the market for low tech ``dirtier'' engines will dry up * 
* * (b) one hundred percent of the production equipment and about 
fifty percent of the support equipment will be equipped with 
filters; (c) about thirty percent of all equipment will need to be 
equipped with environmentally controlled cabs; (d) twenty three 
percent of the mines would need new ventilation systems (fans and 
motors); (e) forty percent of the mines will need new motors on 
these fans; and (f) thirty two percent of the mines will need major 
ventilation upgrades (66 FR 5889-90).

    Furthermore, we concluded that it would not be feasible to require 
this sector, as a whole, to lower DPM concentrations further, or to 
implement the required controls more swiftly (66 FR 5888).
2. Reasons Why the 2001 Assumptions Are Now Being Questioned.
    During the 4\1/2\ years since the 2001 final rule was promulgated, 
the mining industry and MSHA have gained considerable experience with 
the implementation, use, and cost of DPM control technology. Miners' 
DPM exposures have also have declined significantly from a mean of 
808DPM [mu]g/m\3\ (646TC [mu]g/m\3\ [mu]g/m\3\ 
equivalent) prior to the implementation of the standard, to a mean of 
233TC [mu]g/m\3\ based on current enforcement sampling. The 
industry, however, is encountering economic and technological 
feasibility issues with DPM controls as they strive to reduce levels 
below the interim limit. When we established the 2001 final limit, we 
were expecting some mine operators to encounter difficulties 
implementing control technology because the rule was technology 
forcing. We projected that by this time, practical and effective filter 
technology would be available that could be retrofitted onto most 
underground diesel powered equipment. However, as a result of our 
compliance assistance efforts and through our enforcement of the 
interim limit, we have become aware that this assumption may not be 
valid. The applications, engineering and related technological 
implementation issues that we believed would have been easily solved by 
now are more complex and extensive than previously thought.
    Although DPF systems have been proven to be highly effective in 
reducing elemental carbon, mines are currently experiencing problems 
with selection and implementation of DPF systems for complying with the 
interim limit. Since the final limit will require mines to install more 
DPF systems, these selection and implementation problems will extend 
over a large portion of the mining industry. At this time we believe 
that solutions to the problems of selection and implementation have not 
proceeded as quickly as anticipated since promulgation of the 2001 
final rule and many mines will not be able to achieve the final limit 
by January 20, 2006. Some of the implementation and operational 
difficulties encountered with the controls are discussed in the 
sections below.
    We seek additional information regarding technological difficulties 
and whether they will increase the cost to comply with the final 
concentration limit above that estimated in the 2001 final rule. We are 
particularly interested in whether mine operators have attempted to 
institute DPF systems that are impractical or have failed to work for 
their mining operations. We wish to know what types and sizes of DPFs 
have been evaluated, what types of equipment have been fitted with 
DPFs, what types and horsepower of engines were installed on the 
equipment, details concerning monitoring of equipment exhaust 
temperatures prior to specifying a DPF for a given application, whether 
DPF installations include a provision for backpressure monitoring, DPF 
maintenance intervals, DPF life, the results of any DPF failure mode 
analysis, DPM reductions obtained, and any other data related to in-
mine experiences with DPFs on underground metal and nonmetal mining 
equipment.
    We believe that wider use of alternative fuels and filter 
technology can make the 160TC [mu]g/m\3\ final limit 
feasible if a staggered phase-in approach is adopted. By lowering the 
exposure limit in intervals over five years beginning in January 2007, 
market forces should have sufficient time and incentive to adjust to 
the new standard. Specifically, a reliable alternative fuel 
distribution system should induce mine operators to adopt this 
relatively low-cost method to achieve compliance. The development and 
distribution of alternative fuels is also encouraged by existing tax 
credits. We believe that regional distribution networks are

[[Page 53284]]

beginning to emerge. We seek data on alternative fuel distribution 
systems.
    Retrofit options for self-cleaning filters should increase as the 
filter manufacturers become assured of a reliable market for the 
devices. Use of newer equipment with cleaner engines will also increase 
as older equipment is retired from service. We anticipate that this 
staggered approach will provide the needed time to resolve these 
logistical and operational issues, and consequently, may not increase 
our 2001 projection of the cost of compliance with the rule. During 
this phase-in, we will continue to work with the Diesel Partnership 
(discussed below) and the mining industry to address the DPF selection 
and implementation problems and identify effective solutions for the 
diverse metal and nonmetal mining environment.
    Additionally, we request comments on the percentage of diesel 
equipment, by mine size, in metal and nonmetal mines that currently 
have newer, low DPM emitting engines such as EPA Tier I and Tier 2 
compliant engines. Our 2001 cost estimates were based, in part, on the 
assumption that by the effective date of the final limit, 50% of the 
diesel equipment fleet would have new engines (66 FR 5889). We are 
interested in whether our 2001 assumption was accurate. If the 
percentage is lower than originally estimated, it may require the 
industry to rely even more heavily on filters and other types of 
controls at added costs. Relying on DPFs to be installed on older, 
higher DPM emitting engines may also introduce additional 
implementation issues since DPF manufacturers normally do not recommend 
adding DPFs to older engines. Although we recognize various types of 
controls that mine operators could use to reduce miner exposure to DPM, 
we believe that turnover in equipment to less polluting models and the 
use of DPFs would be the primary method of achieving compliance with 
the final DPM limit.
    We also recognize promising advances in alternative fuel technology 
since the 2001 final rule was promulgated. These fuels can be extremely 
effective in reducing DPM emissions. Additionally, the fuels would be 
in tune with recent U.S. initiatives towards greater energy 
independence. On October 22, 2004, President Bush signed into law a 50-
cent-per-gallon tax credit for producers of bio-diesel. He also 
extended federal tax credits for ethanol through 2007 as part of H.R. 
4520, also known as the American Jobs Creation Act of 2004 (Pub. L. 
108-357).
    Currently, however, logistical problems exist with the distribution 
of these fuels to remote mining areas, and the effect of these fuels on 
power output and operation at high altitude needs to be addressed more 
fully.
    Although MSHA, industry, and the Diesel Partnership are actively 
working to address these concerns, additional time may be needed to 
find effective solutions for the implementation of DPM controls.

B. Background

1. Diversity of Underground Mines Affected By the Final DPM 
Concentration Limit
    The metal and nonmetal mining industry has 177 underground mines 
that use numerous pieces of diesel powered equipment, widely 
distributed throughout each mining operation. These mines employ an 
array of mining technologies to produce commodities including metals 
such as lead, zinc, platinum, gold, silver, etc. Also, there are 
different types of nonmetal mines that produce stone products such as 
limestone, dolomite, sandstone, and marble. Other underground nonmetal 
mines produce clay, potash, trona, soda ash, and salt. Not only do 
these mines vary in the commodities that they produce, but they also 
use different mine designs and mining techniques such as room and 
pillar mining and stope mining. Some of these mines are large, complex 
multilevel mines, while others are small adit-type mines. Ventilation 
levels in these mines also vary widely. Many limestone mines have only 
natural ventilation with variable air movement, whereas trona mines 
have high ventilation rates to dilute and remove methane gas released 
in the mining process. There are also deep metal mines with multiple 
levels that have far less ventilation than that found in underground 
trona mines. Furthermore, many metal and nonmetal mines are located in 
remote areas of the country, at high altitudes, or are subject to 
extremely hot or cold environments. Considering these factors as a 
whole, we have found that there is no single solution to control 
technology that would be effective for all metal and nonmetal mines in 
significantly reducing current DPM levels to or below the final DPM 
concentration limit of 160TC micrograms.
2. Work of the M/NM Diesel Partnership (the Partnership)
    Since promulgation of the January 2001 final rule, we have worked 
with a Partnership that is composed of representatives from the 
National Institute for Occupational Safety and Health (NIOSH), industry 
trade associations, and organized labor. We are not a member of the 
Partnership because of our ongoing DPM rulemaking activities. The 
primary purpose of the Partnership is to identify technologically and 
economically feasible controls using existing and available technology 
that can be retrofitted onto existing diesel powered equipment in 
underground metal and nonmetal mines to reduce diesel particulate 
matter emissions to, or below, our interim and final limits.
    The Partnership has been actively involved with NIOSH in its work 
on diesel particulate control technology including its isolated zone 
studies at the Stillwater Mine in Montana. NIOSH has published the 
following reports of its work with the Partnership: ``The Effectiveness 
of Selected Technologies in Controlling Diesel Emissions in an 
Underground Mine--Isolated Zone Study at Stillwater Mining Company's 
Nye Mine (Phase I Study);'' ``An Evaluation of the Effects of Diesel 
Particulate Filter Systems on Air Quality and Personal Exposure of 
Miners at Stillwater Mining Case Study: Production Zone (Phase II 
Study);'' and, ``The Effectiveness of Reformulated Fuels and 
Aftertreatment Technologies in Controlling Diesel Emissions (Phase 
III--A Study in an Isolated Zone at Stillwater Mining Company's Nye 
Mine August 31-September 11, 2004).'' NIOSH stated in its conclusion to 
the Phase III study that:

    This study did not address the important critical path of 
economic and technical aspects relating to implementation of the 
studied technologies into underground mines. The successful 
implementation of control technologies is predicated on addressing 
issues which are relatively unique to each mine and even to 
individual applications within a given mine. Most of these technical 
and operational issues could be investigated through a series of 
long-term field studies where control technologies would be wisely 
selected and optimized for the applications, performance of the 
technologies would be continuously monitored and the effects of the 
controls on concentrations of diesel pollutants in the mine air 
would be periodically assessed. The findings of such studies would 
allow operators to make informed decisions regarding the selection, 
optimization and implementation of control technologies for its 
applications and maximize the benefits of using those technologies. 
It is recommended that these studies be designed and undertaken 
under the leadership of the Metal/Nonmetal Diesel Partnership.

    On-going NIOSH diesel research related to the Partnership includes 
a contract that the NIOSH Pittsburgh Research Laboratory issued to 
Johnson

[[Page 53285]]

Matthey Catalyst to develop a system to control nitrogen dioxide 
(NO2) emissions from diesel-powered underground mining 
vehicles equipped with the Johnson Matthey's Continuously Regenerating 
Trap (CRT[supreg]) system. This system promotes regeneration at lower 
temperatures and is widely used in urban bus applications. If the 
results of laboratory evaluations show that a system is suitable for 
use in underground mining, NIOSH would continue studying this control 
technology with a long-term field evaluation in an underground mine.

C. Remaining Technological Feasibility Issues

    In January 2001, we concluded that technology existed to sample 
accurately for DPM with a TC method and to bring DPM levels to the 160 
TC level by January 2006 (66 FR at 5889). We further concluded that if 
any particular mine found unforeseen technological barriers to meeting 
the January 2006 deadline, it could apply for an extension of up to two 
additional years to comply with the 160 limit (66 FR at 5889). Our 
discussion of technological feasibility in support of the interim PEL 
of 308EC [mu]g/m\3\ in the June 6, 2005 final rule concluded 
that it was technologically feasible to reduce underground miners' 
exposures to the interim PEL by using available engineering control 
technology and various administrative control methods. In fact, our 
testing at Kennecott Minerals Green's Creek Mine showed that ceramic 
diesel particulate filters (DPFs) were capable of reducing diesel 
exposures by 95%. However, we acknowledged that compliance difficulties 
may be encountered at some mines due to implementation issues and the 
cost of purchasing and installing certain types of controls. 
Specifically, implementation issues may adversely affect the 
feasibility of using DPFs to reduce exposures despite the results 
reported in NIOSH's Phase I Isozone Study.
    Our experience since January 2001 has raised questions on 
technological feasibility for the mining industry as a whole, rather 
than for a small number of individual mines, to meet the 160 TC 
concentration limit by January 20, 2006. When we conducted our baseline 
sampling in 2002 and 2003, we found that over 75% of the underground 
mines covered by the 2001 final rule have levels that would exceed the 
final concentration limit of 160TC micrograms. Our current 
enforcement data indicate that approximately 65% of the underground 
mines covered by the 2001 final rule have levels that would exceed the 
final concentration limit. Although exposures have decreased with 
implementation of controls and enforcement of the interim concentration 
limit, we have tentatively concluded that the 160TC 
microgram final concentration limit presents a significant challenge to 
a substantial number of underground mine operators and compliance may 
not be feasible by January 2006. That conclusion is supported by our 
current enforcement sampling results that indicate that many mining 
operations have exposures above the 160TC concentration 
limit, and availability of effective control technology that will 
reduce exposures to the final limit is speculative at this time. 
Moreover, comments from industry trade associations and individual mine 
operators in the post-January 2001 rulemakings recommended that we 
repeal the 160 limit as technologically infeasible. Organized labor, on 
the other hand, has recommended that a limit below 160 is 
technologically feasible. We request comments on whether compliance is 
technologically feasible by January 2006 and the appropriateness of a 
multi-year phase-in of the final limit. We also request comments and 
data on when the technology will be feasible. Specific technological 
implementation issues are discussed in more detail in the following 
subsections C.1 through C.4.
    We also request comments on whether compliance difficulties may 
lead to another problem by requiring a large number of miners to wear 
respirators until feasible controls are fully implemented. We have 
never had a standard that resulted in a significant percentage of the 
workforce being required to wear respiratory protection, and we are 
concerned about the impact on worker acceptance of the rule and about 
mine operators' ability to remain productive. We are interested in 
public comment on how many miners would need to wear respirators to 
comply with the 2001 final limit and proposed multi-year phase-in of 
the final limit, and whether in each case they would need to wear 
respirators for their entire work shift, whether this amount of 
respirator usage is practical, and any other comments or observations 
concerning this issue.
1. Implementation of Available DPFs
    We continue to project that many mine operators will have to use 
DPFs to reduce DPM levels to the final concentration limit. The mining 
industry maintains that while some operators are using DPFs to control 
miners' exposures to the interim PEL, it is infeasible for them to 
further reduce miners' exposures through expanded use of DPFs.
    While passive DPF regeneration systems are preferred over active 
regeneration systems, many pieces of mining equipment do not have duty 
cycles that will consistently support passive regeneration. Passive 
regeneration is the process where the exhaust gas temperature produced 
by the engine is sufficient to burn off the collected DPM on the DPF. 
Passive regeneration is normally preferred because a DPF can be 
installed on a machine, and the operator does not have to be concerned 
with removing the DPF on a routine schedule that may occur at the end 
of every shift. However, passive regeneration does require the machine 
operator to monitor the engine's exhaust gas backpressure. As the DPF 
loads up with DPM, the inability of the exhaust gas to burn off the DPM 
allows the backpressure to increase. Increasing the backpressure above 
the manufacturer's specifications can cause engine and DPF damage. We 
request information on the number of currently installed passive 
regeneration DPF filters. Also, we are interested in the methods used 
by the industry to match a passive regeneration DPF to a machine. 
However, we are aware that two identical machines operating in two 
different mines may not both be able to use passive regeneration. We 
would be interested in comments about practical experience with these 
implementation issues.
    If passive regeneration is infeasible, active regeneration is an 
alternative. Active regeneration depends on an external heat source for 
burning off the DPM. Mine operators have informed us that some mining 
operations cannot utilize active regeneration due to physical size of 
filters, machine down time, or the cost associated with underground 
regeneration stations required for DPF regeneration. We request that 
commenters submit information from the mines that are utilizing active 
regeneration including data regarding the benefits and the 
practicability of active regenerating filters.
    Engine emissions and exhaust flows also affect the size of the DPF 
that needs to be installed. Both of these factors can affect both 
passive and active regeneration. If the DPF is undersized for a 
particular application due to high DPM emissions or high exhaust flows, 
a passive or active DPF system may not make it through the entire shift 
before it must be taken out of service for regeneration because of the 
high backpressure.

[[Page 53286]]

    While some of the mining industry has made improvements by 
replacing older engines with newer engines in order to reduce DPM 
emissions, we believe this has occurred mostly for the larger 
horsepower engines, greater than 150 hp. Smaller engines normally found 
in the support equipment have not had DPM reductions equivalent to the 
larger engines. Since we estimated that 50% of the support equipment 
would probably need DPFs for compliance with the final limit (66 FR 
5889-90), the higher DPM emissions from the engines used in support 
equipment can further complicate the impact on compliance. The mining 
industry has stated that it needs additional time to further evaluate 
the proper sizing of DPF systems for both passive and active 
regeneration.
    We seek further comment regarding these technological 
implementation issues as they affect feasibility of compliance with the 
final concentration limit including the practicality of available DPM 
control technology. We request that the mining community specifically 
address issues surrounding off-board regeneration: back pressure build 
up; frequency of the necessity to clean DPFs; the difficulty of 
placement of regeneration stations; and information on the extent to 
which diesel powered equipment accommodates a retrofit of the DPF.
2. Benefits of On-Board Regeneration
    a. ArvinMeritor[supreg] System. The ArvinMeritor[supreg] system, 
which utilizes active regeneration of the DPF, offers great potential 
for underground mines in further reducing DPM exposures. The 
ArvinMeritor[supreg] system utilizes an on-board fuel burner system to 
regenerate DPFs. This system actively regenerates the filter media 
during normal equipment operations by causing the fuel to ignite the 
burner and thereby increase the exhaust temperature in the filter 
system. Consequently, this system does not require the host vehicle to 
travel to a regeneration station to regenerate the DPF. The condition 
of the DPF is monitored via sensors. While this product was 
successfully evaluated at Stillwater's Nye Mine, we have recently 
learned that the manufacturer has decided to concentrate on working 
with Original Equipment Manufacturers (OEMs) where they would be 
selling 50 units or more to one customer rather than selling one or two 
units per customer.
    b. Johnson Matthey's CRT[supreg] System for DPM reduction (Johnson 
Matthey). As stated above, passive regeneration works by using the 
exhaust gas generated by the engine to burn the DPM. Normally, DPF 
manufacturers utilize catalyst technology to lower the temperature 
needed for successful passive regeneration. By lowering the exhaust gas 
temperature needed for passive regeneration, a broader range of 
machines will have the necessary duty cycle to generate the exhaust gas 
temperature needed to burn the DPM. However, when a platinum coating is 
used as the catalyst, it can also increase the nitrogen dioxide 
(NO2) emissions from the engine exhaust. In mines with low 
ventilation rates, the increased NO2 emissions can also 
result in increased NO2 exposures to potentially dangerous 
levels for miners. We discuss this issue in the final rule on the 
interim PEL (70 FR 32924-26). Therefore, other methods for passive 
regeneration are being developed to resolve these issues.
    In 2004, the NIOSH Pittsburgh Research Laboratory issued a contract 
to Johnson Matthey to develop a system that can regenerate at lower 
exhaust gas temperatures and control NO2 emissions. The 
system is based on Johnson Matthey's CRT[supreg] system and promotes 
regeneration at lower temperatures. Such DPFs are widely used in urban 
bus applications and are capable of passively regenerating DPFs at the 
temperatures commonly seen in the exhausts of underground mining 
equipment (above 250 [deg]C for at least 40% of the operation time).
    The laboratory evaluation of the systems is being executed under 
NIOSH contract by the Center for Diesel Research (CDR) at the 
University of Minnesota. The objective is to examine performance and 
suitability of the systems relative to heavy-duty diesel engines in 
underground mining applications, with specific focus on the 
effectiveness of controlling NO2. If the results of 
laboratory evaluations show that the system is suitable for use in 
underground applications, NIOSH would continue to study this promising 
control with a long-term field evaluation in an underground mine 
environment. We request comments from the mining community regarding 
the foreseeable utility of these and other new control technologies for 
reducing DPM levels in underground metal and nonmetal mines.
3. Operators' Limited Access to Alternative Fuels and Ultra Low-Sulphur 
Fuels
    During our compliance assistance efforts, we observed mines with 
several applications of alternative fuels, including water emulsion 
fuels and bio-diesel fuels both of which are EPA approved fuels. We 
subsequently tested these alternative fuels to determine if they could 
decrease tailpipe DPM emissions. In each application the change to an 
alternative fuel had a positive impact on reducing engine emissions and 
miners' exposures to DPM. In some cases, reductions of 50 to 80+ 
percent were measured. While we found notable benefits, the use of 
alternative fuels can also cause equipment operation issues for mine 
operators. These operational issues have included initial clogging of 
the fuel filters when bio-diesel is used, reduction of horsepower with 
the use of water emulsion fuels, and management of proper fueling of 
the correct fuel into specific machines. While these operational issues 
could be overcome, each mine has to work through implementation issues 
on a case-by-case basis.
    The most common problem with alternative fuels is lack of 
geographic proximity of most mines to a fuel distributor. Fuel 
distribution centers tend to be near large cities. As a result, 
alternative fuels need to be transported to mine sites, in some cases 
significantly increasing costs. Fuel manufacturers are building 
distribution centers near mining areas to reduce the transportation 
costs, but these centers will take some additional time to complete. 
Limited distribution is also a feasibility issue for metal and nonmetal 
mine operators who seek to obtain ultra low sulfur fuel. However, as 
discussed elsewhere in this preamble, the commercial availability of 
ultra low sulfur fuel will increase during 2006 and beyond when on-
highway vehicles in the United States will be required by the EPA to 
use only this type of diesel fuel.
    a. Water Emulsion Fuels. Water emulsion fuels, such as PuriNox, are 
blends of diesel fuels and water. The water is held in suspension with 
a surfactant. The water in the fuel reduces the engine combustion 
temperature resulting in reduced NO2 and reduced DPM 
emissions. However, the added water also reduces the engine's 
horsepower. While the per gallon price of the water emulsion fuel is 
the same as standard fuel, we are aware of increases in engine 
consumption of these fuels by as much as 15 percent. However, continued 
increased use in mines is currently limited due to lack of fuel 
availability in most mining regions. Manufacturers of this fuel must 
install centralized blender facilities in order to make the fuel more 
available and economically feasible for use by the metal and nonmetal 
mining industry.
    Some fuel system issues have also been observed with some engines 
using water emulsion fuels. One issue appears

[[Page 53287]]

to be with the use of very efficient water separators used on engine 
fuel systems to remove water from the fuel lines. A very efficient 
water separator will actually remove the water from the emulsion, thus 
affecting the engine's performance. An engine manufacturer that has 
experienced this with its engines has recommended replacing the more 
efficient water separator with a less efficient one.
    Another issue identified by some mine operators is that some small 
machines cannot run, or run poorly, on this fuel. We are not aware of 
any testing that has been done to prove or disprove this. This may or 
may not be due to less complex fuel systems that cannot handle a change 
in fuel properties. We request any information that would help a mine 
operator determine if certain machines in a fleet cannot run 
efficiently on this type of fuel.
    Since water emulsion fuels have been associated with horsepower 
loss, mines will have to determine through their own in-mine test if 
their machines can continue to operate efficiently even with the power 
loss. Some situations where the power loss could affect a machine's 
productivity occur at multilevel underground mines at high altitudes. 
Also, mines that require the use of permissible engines with pre-
chamber combustion, such as the metal and nonmetal gassy mines, may 
need to determine any additional effects on these types of engines. 
These mines may need additional time to assess the impact of the 
elevation and grade on power loss. We request comments on the mining 
industry's experience with using water emulsion fuels to reduce DPM 
exposures.
    b. Bio-Diesel Fuels. While bio-diesel fuels are more readily 
available than water emulsion fuels, there has not been a consistent 
supply or standard cost of the fuel. Both costs and demand for these 
fuels in the mining industry have been related primarily to tax credits 
available for using the fuel. With current tax credits, bio-diesel can 
be an attractive fuel alternative for the mining industry. However, we 
have observed maintenance issues with application of bio-diesel fuels 
similar to those associated with water emulsion fuels. Particularly, 
bio-diesel functions as a solvent and cleans the fuel system. This 
results in increased clogging and replacement of fuel filters. It may 
take the mining industry some additional time to assess the impact of 
the increased maintenance on a mining operation.
    The other issue related to the use of bio-diesel fuel is the 
percent of soy oil in the mixture. While any blend is available, B20 is 
a 20 percent blend, and B50 is a 50 percent blend, etc., we note that 
significant DPM reductions are not realized unless the bio-diesel blend 
exceeds 20 percent. We request comments on the mining industry's 
experience with using bio-diesel fuels to reduce DPM exposures.
4. Installation of Environmental Cabs
    Environmental cabs are a proven means to reduce worker exposure to 
DPM. While much of the construction-type equipment used in underground 
stone mines comes equipped with environmental cabs, the cabs on 
specialty mining equipment used in underground hard rock mining are 
less common, particularly in mines with narrow drifts or low seam 
heights. As mine operators realize the benefits of cabs, more and more 
pieces of equipment are being purchased or retrofitted with 
environmental cabs. These cabs provide protection for workers not only 
from diesel particulate but also from noise and dust.
    Many mines have begun a retrofit program, but may require 
additional time to design and retrofit specialty mining equipment with 
environmental cabs. We request comments on the mining industry's 
experience with using environmental cabs to reduce DPM exposures.

V. Complexity of Developing an Appropriate Conversion Factor for the 
Final Concentration Limit

    The June 6, 2005 rule uses a 1.3 conversion factor to convert the 
interim PEL of 400TC [mu]g/m3 to 308EC 
[mu]g/m3, because EC comprises only a fraction of TC. We 
used a factor of 1.3, to be divided into 400TC [mu]g/
m3, to produce a reasonable estimate of TC without 
interferences. The EC interim limit is based on the median TC to EC 
(TC/EC) ratio of 1.3 that was observed for valid samples in the 31-Mine 
Study and agreed to in the second partial DPM settlement agreement (70 
FR 32944). Enforcement sample results to date have also shown that for 
the 400TC [mu]g/m3 interim limit, 1.3 is the most 
appropriate conversion factor.
    However, we believe at this time that the 1.3 conversion factor may 
not be appropriate to convert the final phased-in TC limits to EC 
because of the variety of DPM controls being adopted by mine operators 
since the 31-Mine Study. Depending on the types of DPM controls being 
installed at the mines, a new conversion factor for EC may be needed. 
Clean engines have more of an impact on reducing OC levels. Alternative 
fuels, ventilation, and work practices seem to lower EC and TC at 
similar rates, while DPF and environmental cabs appear to be more 
effective in reducing EC levels. The actual TC to EC ratio could vary 
from mine to mine, and even from one section in a mine to another, 
based on the mix of controls at a mine. We are seeking to maintain the 
level of protection for miners provided by the final limit promulgated 
by the 2001 final rule, pursuant to Section 101(a)(9) of the Mine Act. 
When considering the feasibility of compliance and sampling 
constraints, we believe that the conversion factor from TC to EC for 
the phased-in final limits should take into account the OC and EC 
ratios so that the OC and EC components together would be equivalent to 
a TC concentration. We are working with NIOSH to develop an appropriate 
conversion factor for converting the TC limits of this rulemaking to EC 
limits. Information provided by NIOSH indicated that the ratio of TC to 
EC in the 31-Mine Study is 1.25 to 1.67 (70 FR 32944). NIOSH's report 
on the Phase I study conducted in May, 2003, shows that the EC 
reduction in the isolated zone with one DPF system was 88% and that two 
other systems gave greater than 96% EC reductions when the measured 
concentrations were normalized by ventilation rate. In the final report 
of the Phase II study, NIOSH indicated that higher EC reductions were 
observed in the field than were obtained in the laboratory for whole 
diesel particulate. The results of these studies, as well as other mine 
studies NIOSH has conducted, help inform us of the EC to TC ratio at 
different DPM concentrations. Measuring only the EC component ensures 
that only diesel particulate material is being measured. However, there 
are no established relationships between the concentration of EC and 
total DPM under various operating conditions. We welcome comments 
regarding the types of data we should request from NIOSH to assist us 
in developing an appropriate conversion factor for converting the TC 
limits of this proposed rule to EC limits.
    We will initiate a separate rulemaking to determine what the 
correct TC to EC conversion factor will be for the phased-in final 
limits. In the meantime, we are interested in receiving comments on 
whether the record supports an EC PEL without regard to any conversion 
factor, the appropriate conversion factor if one is used, and any other 
scientific approaches for converting the existing TC limit to an 
appropriate EC limit. However, if a rulemaking to establish a 
conversion factor is not complete before January 20, 2007, we are 
considering

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using the current 1.3 conversion factor that we used to establish the 
interim DPM PEL of 308 EC micrograms to convert the phased-in final DPM 
TC limits to EC equivalents. As we did with the interim TC limit 
pursuant to the July 2002 settlement, we would use the EC equivalents 
as a check to validate that an overexposure is not the result of 
interferences. We are interested in receiving comments on this approach 
to enforcement of the 2007 PEL, assuming the conversion factor 
rulemaking is not completed before January 20, 2007.

VI. Economic Feasibility

    In January 2001, we estimated that yearly cost of the final rule 
would be about 0.67% of yearly industry revenue, which was less than 
the 1% ``screen'' of costs relative to revenues that we use as a 
presumptive benchmark of economic feasibility (66 FR 5889). In this 
rulemaking to consider a phased-in approach to the final concentration 
limit of 160 TC micrograms, we intend to use the entire rulemaking 
record supporting the 2001 final rule and the new information gathered 
during the recent rulemaking to promulgate the new interim PEL. Our 
data in the rulemaking record established that few underground mines 
would experience severe economic hardship from enforcement of the 
interim PEL. Our subsequent enforcement data have confirmed that the 
interim PEL is economically feasible. In order to gain a more thorough 
rulemaking record, particularly in light of recent technological 
developments, we request comments on the economic feasibility of the 
final concentration limit of 160 TC micrograms and implications of the 
proposed phase-in approach on the economic feasibility.

VII. Section 101(a)(9) of the Mine Act

    Section 101(a)(9) of the Mine Act provides that: ``No mandatory 
health or safety standard promulgated under this title shall reduce the 
protection afforded miners by an existing mandatory health or safety 
standard.'' We interpret this provision of the Mine Act to require that 
all of the health or safety benefits resulting from a new standard be 
at least equivalent to all of the health or safety benefits resulting 
from the existing standard when the two sets of benefits are evaluated 
as a whole. The U.S. Court of Appeals for the D.C. Circuit approved 
such a ``net effects'' application of Section 101(a)(9). Int'l Union, 
UMWA v. Federal Mine Safety and Health Admin., 407 F. 3d 1250, 1256-57 
(DC Cir. 2005).
    We have tentatively concluded at this point that this proposed 
phase-in period of the effective date of existing Sec.  57.5060(b) of 
the 2001 final rule establishing a final DPM concentration limit of 
160TC [mu]g/m3 will not reduce miner protection. 
We are concerned that the final concentration limit may be infeasible 
for the mining industry in January 2006. Feasibility issues with 
respect to operator compliance are discussed above. Also, an additional 
concern is whether an effective sampling strategy exists to enforce the 
final TC concentration limits with TC as the surrogate. Evidence in the 
rulemaking record after January 2001 suggests that, in many cases, 
there is no practical sampling strategy that would adequately remove 
organic carbon interferences that occur when TC is used as the 
surrogate. Furthermore, the DPM settlement agreement does not address 
appropriate enforcement procedures for the final concentration limit. 
We also believe at this time that the 1.3 conversion factor used for 
the final interim limit may not be appropriate for substantially lower 
limits, such as the final TC concentration limit of 160TC 
[mu]g/m3. Thus, we have concluded at this time that it is 
questionable whether the final concentration limit of 160TC 
[mu]g/m3 would provide any more protection for miners than 
the 308EC [mu]g/m3 interim limit. We have the 
burden of proof to confirm that an overexposure to DPM actually 
occurred and the sample result is not due to interferences. If we were 
to enforce the final DPM concentration limit of 160TC [mu]g/
m3, we would need to validate a TC sample result,