A. Statutory and Rulemaking Background

Section 2 of the MINER Act requires underground coal mine operators to develop and adopt a written Emergency Response Plan (ERP), which must be approved by MSHA. The ERP provides for the evacuation of all individuals endangered by an emergency and the maintenance of individuals trapped underground. All ERPs must provide for emergency supplies of breathable air for individuals trapped underground sufficient to maintain them for a sustained period of time.

MSHA issued Program Policy Letter (PPL) No. P06V10 (October 24, 2006) to implement section 2 of the MINER Act. The PPL provides guidance to mine operators for developing ERPs and to MSHA District Managers for approving ERPs. MSHA issued Program Information Bulletin (PIB) No. P0703 (February 8, 2007) to provide additional guidance to be used in conjunction with the PPL. The PIB includes options for the quantity of breathable air that would be sufficient to maintain persons for a sustained period of time.

[[Page 80657]]

Section 13 of the MINER Act provides that NIOSH conduct research on refuge alternatives and submit a report on the results of the research to the Secretary of Labor. NIOSH issued its report in January 2008.

Section 13 of the MINER Act also provides that the Secretary of Labor
* * * provide a response to the Committee on Health, Education, Labor, and Pensions of the Senate and the Committee on Education and the Workforce of the House of Representatives containing a description of the actions, if any, that the Secretary intends to take based upon the [NIOSH] report, including proposed regulatory changes and the reasons for such actions.

MSHA reviewed NIOSH's report and determined that refuge alternatives are practical and, when integrated into the mine's comprehensive escape and rescue plans, will increase the chance for survival for persons trapped in underground coal mines.

MSHA published the proposed rule for refuge alternatives on June 16, 2008 (73 FR 34140). MSHA held four public hearings on the proposed rule. The hearings were held on July 29 in Salt Lake City, UT; on July 31 in Charleston, WV; on August 5 in Lexington, KY; and on August 7 in Birmingham, AL. The comment period closed on August 18, 2008. B. Discussion of the Hazard

In developing the final rule, MSHA reviewed a number of underground coal mine accident reports and evaluated its accident and injury data from 1900 through 2006. During that period, 264 miners, who were alive after a mine accident, died later during rescue or escape. MSHA has estimated that recent MSHA standards could have saved the lives of 43 of these miners. Thus, for purposes of estimating benefits, this final rule could potentially have saved the lives of 221 miners over the 107 year period. If refuge alternatives had been available, MSHA estimates that the range of lives saved would have been between a low of 25 percent and a high of 75 percent. Using these estimates, the final rule potentially could save an average of from one to three lives every two years.

The preamble to the proposed rule discussed a number of accidents that reflect typical emergency conditions, hazards, and issues in underground coal mines. The explosions at the Sago Mine on January 2, 2006, and the Darby Mine No. 1 on May 20, 2006, which are especially relevant to this rulemaking, are summarized below.

The explosion at the Sago Mine killed one miner instantly and destroyed seals and filled portions of the mine with toxic levels of carbon monoxide. The remaining 12 miners barricaded themselves on the section when their attempts to evacuate were unsuccessful. The barricade was constructed in an area with high concentrations of carbon monoxide. Eleven miners died before they could be rescued. One miner was rescued, but was severely injured.

The force of the explosion at the Darby Mine No. 1 killed two miners. Four other miners encountered thick smoke and donned their SCSRs while attempting to evacuate. The miners eventually became separated and three died from carbon monoxide poisoning.

C. Timeline for Implementation of the Final Rule

MSHA is providing delayed compliance dates for some sections to give mine operators and applicants the time needed to comply with the stated requirements.

1. By April 30, 2009, an application for approval of a refuge alternative or component must be submitted for first year approval consideration by MSHA in accordance with Sec. 7.503. MSHA expects that first year approvals will be completed by December 31, 2009.

2. By April 30, 2009, mine operators must submit a revised program of instruction to the appropriate District Manager for approval in accordance with Sec. 75.1502. The operator must conduct initial mine emergency evacuation training and drills on refuge alternatives and components, under Sec. 75.1504(b)(3)(ii), (b)(4)(ii), and (b)(6) through (10), within 30 days of program approval.

If the refuge alternatives necessary for the training are not yet available, MSHA will accept, as good faith evidence of compliance with the final rule, a valid, bona fide, written purchase order with a firm delivery date for the refuge alternatives. The mine operator must submit a revised program of instruction to the appropriate District Manager for approval in accordance with Sec. 75.1502 within 30 days of receipt of the refuge alternatives. The operator must conduct initial mine emergency evacuation training and drills on refuge alternatives and components, under Sec. 75.1504(b)(3)(ii), (b)(4)(ii), and (b)(6) through (10), within 30 days of program approval.

3. By December 31, 2009, mine operators must complete the initial annual expectations training on the refuge alternatives and components required by Sec. 75.1504(c). However, if the refuge alternatives or components necessary for the training are not yet available, MSHA will accept, as good faith evidence of compliance with the final rule, a valid, bona fide, written purchase order with a firm delivery date for the refuge alternatives and components. The mine operator must complete the initial annual expectations training on the refuge alternatives and components no later than December 31, 2009 or within 60 days of receipt.

II. SectionbySection Analysis

In developing this final rule, MSHA relied on the NIOSH report on refuge alternatives; research studies on various refuge alternatives; accident investigation reports, especially those for the 2006 Sago and Darby mine explosions; as well as public comments, hearing transcripts, and supporting documentation from all segments of the mining community, including States that already require refuge alternatives.

A. Part 7 Approvals

The approval requirements for refuge alternatives are set out in 30 CFR Part 7Testing by Applicant or ThirdParty. The final rule provides approval criteria, allows alternatives for satisfying the requirements, and promotes the development of new technology. It provides requirements for a complete selfcontained refuge alternative and the following components:

Refuge alternatives also must include provisions for communications, lighting, sanitation, food, water, and first aid. These provisions must be approved in the ERP.

MSHA has a 20year history of administering the part 7 approval program, which has reduced product testing costs and improved approval efficiency. Under the final rule, new subpart L of part 7 requires that an applicant or a thirdparty must test the refuge alternative or component according to the final rule. The applicant, usually a manufacturer, provides the required information and test results to MSHA to demonstrate that the refuge alternative or component meets the applicable technical requirements and test criteria. MSHA will issue an approval for a refuge
[[Page 80658]]
alternative or one of its components based on the Agency's evaluation of the information and test results submitted with the approval application. The MSHA approval under part 7 assures operators and miners that the refuge alternative can be used safely and effectively in underground coal mines and that the components can be used safely with each other.

The existing general provisions of subpart A of part 7 (Sec. Sec. 7.1 through 7.10) apply to the testing and approval of refuge alternatives. Existing Sec. 7.3(f) addresses the certification statement and requires that each application for original approval, subsequent approval, or extension of approval of a product shall include a certification by the applicant that the product meets the design portion of the technical requirements, as specified in the appropriate subpart, and that the applicant will perform the quality assurance functions specified in Sec. 7.7. Consistent with the existing requirement, the applicant must provide a certification for refuge alternatives and components.

In addition, existing Sec. 7.8 addresses postapproval product audits and requires that, on request, the approvalholder make a product available to MSHA for audit at no cost to MSHA, but no more than once a year except for cause. Consistent with the existing requirement, the approvalholder must provide a refuge alternative or component to MSHA for audit.

Section 7.501 Purpose and Scope

Final Sec. 7.501, like the proposal, provides that subpart L establishes requirements for MSHA approval of refuge alternatives and components for use in underground coal mines. It states that the purpose of approved refuge alternatives is to provide a lifesustaining environment for persons trapped underground when escape is impossible. Refuge alternatives also can be used to facilitate escape by sustaining trapped miners until they receive communications regarding escape options or until rescuers arrive.

MSHA considers refuge alternatives as a last resort to protect persons who are unable to escape from an underground coal mine in the event of an emergency. NIOSH stated, in its report on refuge alternatives, that
* * * the potential of refuge alternatives to save lives will only be realized to the extent that mine operators develop comprehensive escape and rescue plans that incorporate refuge alternatives.

Several commenters expressed concern that refuge alternatives have not been proven effective in an actual mine and that human subject testing is necessary for proper functioning and durability of the units. Some commenters requested that MSHA defer promulgating a final rule until human subject testing is completed. Commenters also questioned the use of models and calculations in lieu of human subject testing. However, other commenters stated that human subject testing is not necessary nor is it the best proof of viability. One commenter stated that ``there is enough data available to properly simulate the metabolic heat and breathing of humans without necessarily subjecting humans to the risks of a manned test'' and that ``[t]his is not to say that some manned testing may not be valuable to validate portions [of] the test protocol and for training development.''

The requirements of the final rule are extrapolated from existing Federal and State requirements and from published reports from the U.S. Bureau of Mines and NIOSH. In addition, in developing the final rule, MSHA consulted with experts and other knowledgeable professionals, and evaluated the comments and testimony on the proposal. Based on MSHA's knowledge and experience, the Agency believes that the results of human subject testing, which may be appropriate at some later date, are not necessary for the final rule. Accordingly, the requirements of the final rule are not based on human subject testing.

MSHA continues to work with NIOSH on new technology requirements in the MINER Act. MSHA is aware that NIOSH is developing a protocol and seeking approval for human subject testing. If approved, the results of this human subject testing will not be available prior to the effective date of the final rule. The Agency will consider the results of such testing for future rulemaking, if warranted.

MSHA has analyzed various design specifications of manufactured refuge alternatives and has developed approval requirements that manufacturers must follow. Except as otherwise provided in the rule, mine operators are permitted to use only refuge alternatives and components for which the design specifications have been approved by MSHA. MSHA recognizes that, under the Mine Act, States generally may enact laws or prescribe by regulation additional refuge alternative requirements to the extent they are more stringent than MSHA's standards. Such laws and regulations are limited by principles of conflict preemption to requiring specific refuge alternatives that have been approved by MSHA, and cannot under any circumstances require the use of a refuge alternative that has not been approved. Moreover, it is MSHA's intent that its approval of specifications for a refuge alternative preempts private tort litigation questioning the propriety of those specifications. MSHA weighed various tradeoffs in setting requirements for approved refuge alternatives and components, such as those involved in arriving at space and volume requirements and strength requirements. Refuge alternatives and components cannot be altered once approved without seeking potentially timeconsuming approval for modifications. Tort suits deeming approved designs insufficient could introduce statebystate uncertainty to national manufacturers, thereby threatening the steady commercial supply of refuge alternatives and components and potentially leaving miners unprotected.

Section 7.502 Definitions

Final Sec. 7.502, like the proposal, establishes a number of definitions because refuge alternatives represent a relatively new technology for underground coal mines and the terminology may not be widely understood.

One commenter requested that a definition of ``component'' and ``examinable'' be included. MSHA does not believe that the Agency needs to define the term ``component'' because several sections in the final rule identify the four types of componentsstructural, breathable air, airmonitoring, and harmful gas removaland their specific
requirements. The final rule also clarifies examinations and inspections for structural components.

Apparent Temperature

The final rule clarifies the proposal, and defines apparent temperature as the measure of relative discomfort due to the combined effects of air movement, heat, and humidity on the human body. The final rule clarifies MSHA's intent that the term is used to measure relative discomfort. When no air movement is present, the apparent temperature equals the heat index. As heat and humidity increase, the amount of evaporation of sweat from the body decreases. MSHA received a comment that the Agency should specify the method for determining apparent temperature as part of the definition. The Agency has not specified the method in the definition, which is unchanged; however, the apparent temperature is addressed in the final rule under Sec. 7.504(b).
[[Page 80659]]

Breathable Oxygen

The final rule, like the proposal, defines breathable oxygen as oxygen that is at least 99 percent pure with no harmful contaminants. Some commenters suggested that MSHA provide performancebased approval criteria to promote innovative new technology, and that the proposal was unnecessarily restrictive. The final rule, like the proposal, includes necessary parameters for oxygen purity.

One commenter suggested that the final rule include a definition of breathable air. MSHA issued a Program Information Bulletin on Breathable Air (PIB P0703), which addressed the recommended standards for breathable air as identified by the American National Standards Institute (ANSI)/Compressed Gas Association (CGA) Commodity Specifications for Grade D Breathable Compressed Air. Accordingly, the final rule does not define breathable air.

Flash Fire

The final rule, like the proposal, defines flash fire as a fire that rapidly spreads through a diffuse fuel, such as airborne coal dust or methane, without producing damaging pressure. MSHA notes that a flash fire may occur in an environment, such as an underground coal mine, where fuel and air become mixed in adequate concentrations to combust. In an underground coal mine, a flash fire can be a rapidly moving flame front from a combustion explosion. In its report, NIOSH recommended that the fire resistance for refuge alternatives be 300 [deg]F for 3 seconds. NIOSH based its recommendation on NFPA 21132007, the National Fire Protection Association's ``Standard on Selection, Care, Use, and Maintenance of FlameResistant Garments for Protection of Industrial Personnel Against Flash Fire,'' but advised that additional investigation is warranted.

A flash fire is defined by NFPA 2113 as ``a fire that spreads rapidly through a diffuse fuel, such as dust, gas, or vapors of an ignitable liquid, without the production of damaging pressure.'' NFPA 2113 also includes a longer explanation of flash fire in the Annex A.3.3.16. This explanation addresses flame temperatures for diffused fuel flash fires ranging from 1,000[deg] to 1,900 [deg]F. A commenter requested that MSHA clarify the definition of flash fire by adding that a flash fire is not an ongoing fire. MSHA has explained heat transfer and duration and believes the definition given is adequate. The final rule is unchanged.

Noncombustible Material

The final rule, like the proposal, defines noncombustible material as material, such as concrete or steel, that will not ignite, burn, support combustion, or release flammable vapors when subjected to fire or heat. MSHA received one comment requesting modification of the proposed definition to include tent deployment information. MSHA has addressed this comment elsewhere in this preamble under final Sec. 7.505(a)(6) and believes that the proposed definition is adequate. The final rule is unchanged.

Overpressure

The final rule, like the proposal, defines overpressure as the highest pressure over the background atmospheric pressure that could result from an explosion, which includes the impact of the pressure wave on an object. MSHA notes that explosion pressures are normally expressed as an overpressure beyond standard atmospheric pressure. Standard atmospheric pressure is 14.7 pounds per square inch (psi) (one atmosphere) at sea level. For example, air pressure in a car tire is measured with a pressure gauge as 30 psi, which is an overpressure. The absolute pressure of the air inside the tire is 44.7 psi. One commenter supported and no commenters opposed the proposal.

Refuge Alternative

The final rule, like the proposal, defines refuge alternative as a protected, secure space with an isolated atmosphere and integrated components that create a lifesustaining environment for persons trapped in an underground coal mine.

One commenter requested that the proposed definition be modified to emphasize the importance of protecting persons from toxic gases entering the space prior to occupancy and to allow the use of an individual breathable air supply. Under the final rule, refuge alternatives must have an isolated atmosphere and lifesustaining environment. Another commenter requested that the term be defined with more clarity. MSHA believes that the definition as stated provides sufficient detail and concludes that no change to the final rule is necessary.

Section 7.503 Application Requirements

Final Sec. 7.503(a), like the proposal, requires that an application include information to assure that MSHA can determine if a refuge alternative or component meets the technical requirements for approval, functions as intended, and is safe for use in an underground coal mine.

Final paragraph (a)(1), like the proposal, requires that the application contain the refuge alternative's or component's make and model number, if applicable. This provision assists MSHA in identifying specific units or parts from different companies.

One commenter requested that the final rule allow approval of design criteria rather than approval of specific models. MSHA has considered the implications of making this change, such as auditing critical characteristics and integration of components, and determined that no change to the rule is necessary.

Final paragraph (a)(2)(i), like the proposal, requires that the application list the refuge alternative's or component's parts, and include the MSHA approval number for electricpowered equipment. With the approval number, MSHA would be able to verify that electricpowered equipment is either approved as permissible or, with respect to certain equipment such as airmonitoring equipment or gas detectors, is approved as intrinsically safe. MSHA received no comments on this provision.

Final paragraph (a)(2)(ii), like the proposal, requires that the list of a refuge alternative's or component's parts in the application include each component's or part's inmine shelf life, service life, and recommended replacement schedule. Comments concerning shelf life, service life, and replacement schedule are addressed elsewhere in this preamble under final Sec. Sec. 7.508(c)(4) and 75.1506(a)(3).

Final paragraph (a)(2)(iii) clarifies the proposal and requires that the application list the refuge alternative's or component's parts that include materials, which have a potential to ignite, used in each component or part with their MSHA approval number. The proposal would have required that the application list the materials used in each component or part with their MSHA approval number or statement that the materials are noncombustible. One commenter stated that not all materials used in refuge alternatives or components can be noncombustible. Another commenter requested clarification of noncombustible materials and MSHA approved electrical components. The final rule clarifies that the MSHA approval number must be included for materials that have a potential to ignite. This provision helps assure that materials are safe for use in an underground coal mine. The hazardous nature of an underground coal mine requires that
[[Page 80660]]
sources of ignition be eliminated. The confined space of an underground coal mine necessitates that materials be designed so that they will not contribute to a fire or give off harmful gases when exposed to heat.

Final paragraph (a)(2)(iv) was not in the proposed rule. It requires that the application list the refuge alternative's or component's parts that include a statement that the component or part is compatible with other components; and upon replacement, is equivalent to the original component or part.

Commenters expressed concern regarding the reliability of refuge alternatives that consist of multiple separate components. Some commenters opposed mixing different models of breathable air components because miners might get confused during an emergency and be placed at greater risk.

This new provision is responsive to comments and clarifies MSHA's intent to assure that components or parts that are approved must be interchangeable or must integrate with the other components or parts in the refuge alternative so that the refuge alternative will continue to operate as intended. Under the final rule, if the component or part is a replacement, it must be equivalent to the original component or part. The component or part must be designed for the capacity of the refuge alternative for which it is intended.

Final paragraph (a)(3) is substantively the same as the proposal. It requires that the application specify the capacity and duration (the number of persons it is designed to maintain and for how long) of the refuge alternative or component. For example, the application must include a specific length of time that the refuge alternative or component could support a specified number of persons. This information is necessary so that MSHA can appropriately evaluate the performance of the refuge alternative or component and determine if it meets the requirement that it sustain persons for 96 hours. The final rule includes a nonsubstantive change. It does not include the ``perperson perday'' measurement. Comments on capacity and duration and shift changeover are discussed elsewhere in this preamble under final Sec. 75.1506(b)(2).

Final paragraph (a)(4), like the proposal, requires that the application specify the length, width, and height of the space required for storage of each component. The Agency needs this information for components approved separately to assure that the refuge alternative will have enough usable space for occupants when all components are stored. MSHA did not receive comments on this provision.

Final Sec. 7.503(b), like the proposal, requires that the application provide additional specific information. Final paragraph (b)(1) requires that the application specify a description of the breathable air component, including drawings, airsupply sources, piping, regulators, and controls. This information establishes that the component is included and is in its proper location. MSHA received no comments on the proposed requirement.

Final paragraph (b)(2) requires that the application specify the maximum volume of the refuge alternative, excluding the airlock; the dimensions of floor space and volume provided for each person using the refuge alternative; and the floor space and volume of the airlock. This information assures that there is adequate usable space for occupants when all components, parts, equipment, and material are shown in drawings under paragraph (b)(6) in their respective place.

One commenter stated that the phrase in the preamble ``in their respective place'' implied that the rule required defined locations for specific items. The final rule clarifies that the application specify the dimensions of floor space and volume for each person to assure that the space and volume provided for persons is usable and not reserved for storage.

Another commenter questioned why the airlock in a unit is excluded from the space calculations. In response to comments, final Sec. Sec. 7.505(a)(1) and 75.1506(b)(1) clarify that the airlock may be included in the space and volume of the refuge alternative if waste is disposed outside the unit. Therefore, final Sec. 7.503(b)(2) replaces the term ``interior dimensions'' of the airlock with ``floor space and volume'' of the airlock which must be included in the application.

Final paragraph (b)(3), like the proposal, requires that the application specify the maximum positive pressures in the interior space and airlock and a description of the means used to limit or control the positive pressure. This information allows MSHA to determine whether the atmospheric pressure in the refuge alternative will maintain good air, without being excessive, as persons enter and pass through the airlock. Excessive pressure could create adverse physiological effects on persons. MSHA did not receive comments on this provision. The final rule includes a nonsubstantive change. MSHA deleted the term ``allowable.''

Final paragraph (b)(4), like the proposal, requires that the application specify the maximum allowable apparent temperature of the interior space and the airlock and the means to control the apparent temperature. MSHA will use this information to evaluate the approval of the refuge alternative. MSHA did not receive comments on this provision. Comments concerning the apparent temperature inside the refuge alternative are discussed elsewhere in this preamble under Sec. 7.504(b)(1).

Paragraph (b)(5) is new and provides further clarification of the Agency's intent with respect to controlling internal apparent temperature. This provision requires that applicants specify in the application the maximum mine air temperature under which the refuge alternative is designed to operate when the unit is fully occupied.

This provision is added in response to commenters' concerns regarding the effect that the mine temperature has on the internal apparent temperature in the refuge alternative. Commenters stated that the temperature outside of the unit must be taken into consideration because of heat transfer. This provision corresponds to the requirement in Sec. 75.1507(a)(12) that the Emergency Response Plan (ERP) include the maximum mine air temperature at each of the locations where refuge alternatives are to be placed.

Final paragraph (b)(6) is redesignated from proposed paragraph (b)(5). Like the proposal, it requires that each application include drawings that show the features of each component and contain sufficient information to document compliance with the technical requirements. MSHA's intent is that the drawings of each component should illustrate the internal configuration of the refuge alternative. Drawings should include the dimensions and layout of the refuge alternative components, controls, and materials necessary for proper operation. This information provides a basis for MSHA approval of the refuge alternative. MSHA did not receive comments on this provision.

Final paragraph (b)(7) is redesignated from proposed paragraph (b)(6) and has been changed from the proposal. It requires that the applicant provide a manual rather than a training manual that contains sufficient detail for each refuge alternative or component addressing inmine transportation, operation, and maintenance of the unit.

Commenters generally supported the proposal. However, one commenter expressed concern that the manuals not be used as a substitute for miner training because the manufacturer's manual may be too detailed and complicated. Another commenter requested that training materials include
[[Page 80661]]
detailed information on turning off devices between readings to conserve battery life and adjusting oxygen flow. Another commenter stated the manual should be written in a manner that includes individual mine specific information such as SCSR caches, communication and tracking, and life lines.

MSHA recognizes that, in general, manufacturers provide information necessary for safe and effective use of their products. Consistent with this general practice, the final rule requires the applicant to provide a manual which contains detailed information on inmine transportation, operation, and maintenance of the refuge alternative. The manual would be used by MSHA to evaluate and approve the refuge alternative. The final rule clarifies MSHA's intent that the manual be used by operators to develop training material required under Sec. 75.1502(c), concerning mine emergency evacuation program of instruction; Sec. 75.1504(b), concerning quarterly training; Sec. 75.1504(c), concerning annual expectations training; and Sec. 75.1508 concerning training on examinations, maintenance, or repairs.

Final paragraph (b)(8) is redesignated from proposed paragraph (b)(7) and has been changed from the proposal. It clarifies that the applicant must provide a summary of procedures for deploying refuge alternatives. MSHA will use this information to evaluate the approval and the operator may use this information to develop instructions for persons in the deployment of refuge alternatives. This provision changes the proposed requirement that the applicant provide a summary of procedures for ``constructing'' refuge alternatives because prefabricated units do not require construction, and the structural components of units consisting of 15 psi stoppings constructed prior to an event do not require approval under part 7.

Final paragraph (b)(9), redesignated from proposed paragraph (b)(8) and the same as the proposal, requires that the application include a summary of the procedures for using the refuge alternative. This information will be used by MSHA to evaluate the approval and by operators to develop instructions for persons using refuge alternatives. MSHA did not receive comments on this provision.

Final paragraph (b)(10), redesignated from proposed paragraph (b)(9) and the same as the proposal, requires that the application specify the results of inspections, evaluations, calculations, and tests conducted under this subpart. MSHA will use this information to evaluate the effectiveness and compatibility of refuge alternative components. For example, the application must contain the calculation of the rate oxygen is delivered on a per person basis and the results of tests, including calculations, of the carbon dioxide removal (scrubbing) to demonstrate that the refuge alternative will maintain a safe atmosphere for 96 hours. Without having these calculations readily available, the Agency would have difficulty independently verifying that the test results are satisfactory. MSHA did not receive comments on this provision.

Final Sec. 7.503(c), like the proposal, requires that the application for approval of the airmonitoring component provide specific information. This information is necessary for the applicant or third party to make an effective evaluation of the component and to provide a basis for MSHA approval of the airmonitoring component.

Final paragraph (c)(1), like the proposal, requires that the application specify the operating range, type of sensor, gases measured, and any environmental limitations including the cross sensitivity to other gases, of each detector or device in the air monitoring component. The Agency believes that this information is essential for MSHA to determine that persons inside the refuge alternative will be aware of the concentrations of carbon dioxide, carbon monoxide, and methane, inside and outside the refuge alternative, including the airlock. In addition, this will assure that oxygen concentrations can be monitored simultaneously. MSHA did not receive comments on this provision.

Final paragraph (c)(2), like the proposal, requires that the application include the procedures for operation of the individual devices so that they function as necessary to test gas concentrations over a 96hour period. Manufacturers must properly design the system to control gas concentrations inside the refuge alternative. This provision will assist MSHA's evaluation of the airmonitoring component.

One commenter stated that ``few if any monitors exist that will operate for 96 hours continuously.'' The commenter stated that provisions must be made for recharging or changing batteries and that instrument manufacturers should provide ``options for extending the operational life of their devices in a potentially explosive atmosphere.'' In the proposal, MSHA did not state that air monitoring instruments or devices were intended to operate continuously. This issue is discussed elsewhere in this preamble under Sec. 7.507 concerning air monitoring components. The Agency anticipates that refuge alternative manufacturers will work with monitoring instrument manufacturers to satisfy the requirements of this provision. The final rule is the same as the proposal, except for an editorial change for clarity.

Final paragraph (c)(3), like the proposal, requires that the application include procedures for monitoring and maintaining breathable air in the airlock, before and after purging. Monitoring and maintaining breathable air in the airlock is necessary to remove contaminants and minimize contamination inside the refuge alternative as miners pass through the airlock into the interior space. MSHA did not receive comments on this provision.

Final paragraph (c)(4), like the proposal, requires that the application include instructions for determining the quality of the atmosphere in the airlock and refuge alternative interior and a means to maintain breathable air in the airlock. Determining the quality of the air and maintaining breathable air are necessary to sustain trapped miners. MSHA did not receive comments on this provision.

Final Sec. 7.503(d)(1) and (2), like the proposal, require that the application for approval of the harmful gas removal component specify the volume of breathable air available for removing harmful gas both at startup and while persons enter through the airlock; and the maximum volume of each gas that the component is designed to remove on a perperson perhour basis. Information on harmful gas removal is essential for MSHA to determine the ability of the refuge alternative to sustain occupants for 96 hours. These final provisions also provide information on the removal of carbon dioxide that is exhaled by the occupants and the removal of other harmful gases.

One commenter stated that this provision is not practical and should be removed. Another commenter recommended that the requirement be performancebased. MSHA does not agree since the Agency needs this information to evaluate the adequacy of the harmful gas removal systems to meet the needs of the occupants for 96 hours. The applicant can calculate the amount of purge air available or scrubbing capability for a range of expected conditions. MSHA expects the application to contain sufficient information to enable the Agency to determine whether the refuge alternative or component meets the technical and performance requirements of this subpart.

[[Page 80662]]

Proposed Sec. 7.503(e) is not included in the final rule. It would have required the applicant to certify that each component was constructed of suitable materials, was of good quality workmanship, was based on sound engineering principles, was safe for its intended use, and was designed to be compatible with other components in the refuge alternative, within the limitations specified in the approval.

Several commenters objected to the Agency's use of ``subjective terms.'' One commenter stated that the provision ``leaves itself open to a broad range of interpretations that will result in considerable confusion on the part of applicants and reviewers.'' Commenters stated that the final rule ``must have specific parameters that are measurable and have a clear limit beyond which they fail'' and ``stipulate what these phrases exactly mean'' or remove the provision.

Due to commenters concerns, MSHA evaluated the information, design criteria, and testing results required to be specified in the application for approval. Based on this evaluation, MSHA determined that the content of the application will be sufficient to allow MSHA to evaluate whether the refuge alternative or component meets the requirements for approval. In addition, existing Sec. 7.3(f) requires an applicant's certification that the product meets the requirements specified in the appropriate subpart. Also, to clarify the Agency's intent, and in response to comments, MSHA added a requirement, final Sec. 7.503(a)(2)(iv), that the application provide a statement that the component is compatible with other components. With this change, and with the existing requirements, the Agency determined that it is not necessary to include proposed Sec. 7.503(e) in the final rule. Section 7.504 Refuge Alternatives and Components; General Requirements

Final Sec. 7.504, like the proposal, addresses safety and health requirements that refuge alternatives and components must meet to gain MSHA approval.

Final Sec. 7.504(a)(1) clarifies the proposal and requires that electrical components that are exposed to the mine atmosphere must be approved as intrinsically safe for use in an underground coal mine. Further, it provides that electrical components located inside the refuge alternative must be either approved as intrinsically safe or approved as permissible.

One commenter supported the proposal stating that refuge alternatives and components should be explosionproof or intrinsically safe. Another commenter stated that the rule should clarify the use of approved permissible electrical equipment and approved intrinsically safe equipment.

The final rule clarifies MSHA's intent that electrical components of refuge alternatives that are exposed to the mine atmosphere must be approved as intrinsically safe. However, because a nonexplosive atmosphere exists inside a refuge alternative, electrical components located inside the unit must be either approved as intrinsically safe or approved as permissible. This provision helps assure that the refuge alternative or component will not contribute to a secondary fire or explosion.

Final paragraph (a)(2), like the proposal, requires that a refuge alternative or component not produce continuous noise levels in excess of 85 dBA in the structure's interior. One commenter stated that noise is not likely to be a problem in a shelter during occupancy and questioned the logic for the proposal. MSHA included this requirement in the final rule because continuous noise above 85 dBA can interfere with communication and could adversely affect hearing, and the Agency is aware that noise controls, such as dampening material, are available to control noise levels.

Final paragraph (a)(3), like the proposal, requires that the refuge alternative or component not liberate harmful or irritating gases or particulates into the structure's interior or airlock. The Agency is aware that some nonmetallic materials offgas. Vapors, aerosols or particulates should not be released into the refuge alternative. The provision requires that materials used in a refuge alternative or component be tested and evaluated to verify that they do not release harmful or irritating gases. The application would have to include the results of the tests and evaluation. No commenters opposed the proposal.

Final paragraph (a)(4), like the proposal, requires that the refuge alternative or component be designed to be moved safely with the use of appropriate devices, such as tow bars. MSHA recognizes that refuge alternatives could be a hazard to miners during transport. Based on MSHA's experience, the Agency believes that inadequate rigging and towing devices could result in hazards to miners. The refuge alternative should be designed with proper connections and devices to eliminate or reduce hazards that may occur when chains, ropes, or slings are used.

Commenters supported the proposal. One commenter noted that the refuge alternative can be moved safely using a tow bar. The final rule remains unchanged from the proposal.

Final paragraph (a)(5), like the proposal, requires that the refuge alternative and components be designed to withstand forces from collisions of the structure during transport and handling. This provision helps assure that the refuge alternative and components are not damaged during transport and handling.

One commenter suggested that all components be subjected to shock testing. Another commenter noted that many mines have required special attachments or bumpers, and requested that the final rule include these modifications.

Different mining conditions warrant different designs. The final rule is performanceoriented, allowing operators to tailor refuge alternative and component designs to the specific conditions in their mines. Designs can incorporate bumpers, guarding, skids, packing and securing devices, and rigging components. In addition, components should be configured, arranged, and stored to minimize shifting, movement, or damage during handling and routine transport. MSHA has evaluated all comments, and determined that the final rule should be the same as the proposal.

Final paragraph Sec. 7.504(b), like the proposal, requires that the apparent inside temperature be controlled. Body heat and heat generated by chemical reactions (i.e., carbon dioxide scrubbing chemicals) are inherent heatproducing sources within a refuge alternative. Ambient temperature in a refuge alternative also is affected by the mine temperature compounded by high humidity in the sealed environment. High humidity reduces a body's ability to regulate temperature by sweating, which could result in a dangerously elevated internal body temperature. The carbon dioxide absorption process also generates heat and humidity. There is currently no permissible air conditioning equipment that will address heat and humidity in underground coal mines.

Final paragraph (b)(1), like the proposal, requires that when a refuge alternative is fully occupied and used in accordance with the manufacturer's instructions and defined limitations, the apparent temperature in the refuge alternative must not exceed 95[deg] Fahrenheit. MSHA requested comments on the apparent temperature and mitigation of heat stress and heat stroke, and requested that commenters address
[[Page 80663]]
the generation of heat and the methods for measuring heat stress on persons occupying the refuge alternative.

Most commenters generally supported the proposal. Some commenters noted that the proposal did not include airconditioning to address metabolic heat buildup. One commenter stated that the proposal stifles creativity and eliminates innovative new technology, and one commenter suggested using chemical cooling packs or cooling vests to maintain core body temperature at a safe level. MSHA believes that there could be methods, including air conditioning, for controlling temperature that would be acceptable under the final rule. Chemical cooling packs or cooling vests may be used to supplement maintaining core body temperature. However, these devices have not been established as reliable, and therefore, may not be used as a substitute to the requirement for maintaining the apparent temperature inside the refuge alternative.

One commenter suggested that it was not appropriate to require an interior temperature without a corresponding ambient rock temperature. MSHA reviewed NIOSH/Raytheon UTD's Report on Miner Refuge Chamber Thermal Analysis (NIOSH/Raytheon report). The NIOSH/Raytheon report concluded that the rock type has a negligible effect on the conduction of heat away from a refuge alternative in an underground mine. In addition, the NIOSH/Raytheon report stated that the amount of heat conducted through the floor of a refuge alternative is small compared to the amount of heat that is carried away by convection. Accordingly, the final rule does not include a provision for corresponding ambient rock temperature.

One commenter stated that the International Standards Organization (ISO) standard, ISO 7243:1989(E), ``Hot environmentsEstimation of the heat stress on working man, based on the WBGTindex (wet bulb globe temperature),'' should be used to evaluate heat stress.

ISO 7243 specifies periods of work and rest based on the air temperature and the level of activity throughout a workday for working in a hot environment daily, with breaks during the day and periods of relief between exposures. The ISO standard does not apply to the conditions addressed by the final rule because persons in a refuge alternative could be exposed for several days without an opportunity to recover.

Apparent temperature is a measure of relative discomfort due to the combined effect of heat and humidity. The concept of apparent temperature was developed by R.G. Steadman (1979) and was based on physiological studies of evaporative skin cooling for various combinations of ambient temperature and humidity. The likelihood of adverse effects from heat may vary with a person's age, health, and body characteristics; however, apparent temperatures greater than 80 [deg]F are generally associated with some discomfort. Core body temperatures in excess of 104 [deg]F are considered lifethreatening, with severe heat exhaustion or heat stroke possible after prolonged exposure or significant physical activity. The December 2007 Foster Miller Report\1\ concluded that the apparent temperature within a confined space occupied by humans should not exceed 95 [deg]F. \1\ Foster Miller. Phase II Report, December 2007.

Based on the Agency's review of many standards, studies, and reports, and the comments and testimony, MSHA believes that applying ISO 7243 could result in dangerously high apparent temperatures in the refuge alternative. This is because the limit specified in ISO 7243 is an 8hour average, not a maximum continuous exposure. Therefore, using the ISO 7243 average as a maximum exposure level would allow as much as 50% higher temperature than even the ISO 7243 standard allows, and for a continuous 96hour period as opposed to 8 hours. This would be fatal to the occupants. Accordingly, the final rule is the same as proposed.

Final paragraph (b)(2) clarifies the proposal and requires that tests be conducted to determine the maximum apparent temperature in the refuge alternative when used at maximum occupancy and in conjunction with required components. In addition, the final rule requires that an application include these test results including calculations. The final rule clarifies MSHA's intent that tests be conducted and that the test results including calculations be reported on the application. Test results could also include data, records, and other supporting documentation reported on the application. MSHA received no comments on this provision.

Final Sec. 7.504(c), like the proposal, requires that refuge alternatives include additional measures to protect the safety and survival of miners. These requirements include a means for communicating with persons on the surface, lighting, sanitation, first aid, and repairs.

Final paragraph (c)(1), requires a twoway communication facility that is a part of the mine communication system, which can be used from inside the refuge alternative; and accommodations for an additional communication system and other requirements as defined in the communications portion of the operator's approved Emergency Response Plan (ERP). MSHA is aware that these additional systems may not yet be available, but as they are developed, mine operators will be required to include them in their ERPs. The MINER Act requires, by June 15, 2009, that ERPs contain wireless communication systems. MSHA is working with NIOSH on this emerging technology and will provide further guidance to the mining community with respect to the Agency's expectations for ``wireless communication'' systems in ERPs. Manufacturers may need to provide other accommodations for these systems. In the final rule, this provision has been revised to reflect the language in the safety standards for communications facilities in this rulemaking. Comments addressing these communication systems are addressed in that section.

In the preamble to the proposed rule and in the Agency's opening statements at the public hearings, MSHA requested comments on including a requirement that refuge alternatives be designed with a means to signal rescuers on the surface. This was intended to be a means to assure that rescuers on the surface could be contacted if the communications systems become inoperable. This signal would have been similar to what miners had done in the past by hammering on the roof, ribs, or floor to create sounds that can be detected by seismic devices located on the surface.

One commenter stated that the final rule should not require the use of a seismic location device unless MSHA is willing to obtain significant upgrades to its seismic capabilities. However, most commenters did not respond to MSHA's request on this issue.

MSHA also requested comments on whether the final rule should include a requirement that the manufacturer design refuge alternatives with a means to signal underground rescuers with a homing device. Such a requirement would assure that rescuers could detect the trapped miners within the mine.

Some commenters supported adding a provision for a homing device in refuge alternatives. They stated that the signal could help rescuers determine whether anyone was in the refuge alternative. Several opposed such a provision, for example, stating that the homing device was unnecessary because there already is a requirement to identify the locations of the units on the escapeway maps.

The final rule, like the proposal, does not contain a provision addressing
[[Page 80664]]
signaling or homing devices. After reviewing the comments, MSHA agrees with commenters opposing such provisions and has determined that the requirements for a signaling device that would create a seismic sound to be detected by rescuers on the surface should not be included in the final rule. Likewise, the Agency has determined that the requirements for a homing device that would create an electronic signal to be detected by rescuers underground should not be included in the final rule.

Final paragraph (c)(2), like the proposal, requires that refuge alternatives include lighting sufficient for persons to perform tasks. Lighting is essential to allow persons to read instructions, warnings, and gauges; operate gas monitoring detectors; and perform other activities related to the operation of the refuge alternatives.

In the preamble to the proposal, MSHA recommended a minimum of 1 foot candle of lighting be provided per miner per day.\2\ The Agency also noted that lighting should not generate significant heat, or require continual manual power for light generation.
\2\ MILSTD1472F, Lighting for bomb shelters, NOTICE 1, 05 December 2003.

Several commenters recommended light sticks and cap lamps. Another commenter stated that MSHA should be flexible with respect to a lighting requirement and that the proposal requires technology that may not be currently available. One commenter stated that MSHA should not require 1 footcandle per day per miner. Another commenter pointed out that there may be added risks of electrical hazards and requested that, as the provision presents more potential problems than it solves, it be omitted from the final rule.

Although MSHA agrees that light sticks can be used, higher intensity lighting may be required for certain tasks. The final rule includes the same performanceoriented requirement as the proposal. The final rule includes a nonsubstantive change. It includes the term ``for persons.''

Final paragraph (c)(3), like the proposal, requires that refuge alternatives include a means to contain human waste effectively and minimize objectionable odors. A plastic bag and closed receptacle could be used to contain waste and prevent objectionable odors. The final rule does not require a specific method of waste disposal. The length, width, and height of the container housing the sanitation system, including operating instructions, should be in the refuge alternative's manual. Information regarding sanitation assures that the applicant has included an adequate means for containing waste.

One commenter pointed out a number of options for sanitation and waste disposal that are currently available. Some commenters requested that the final rule require that human waste be disposed of outside the refuge alternative. Under the final rule, waste can be disposed of from the interior of the refuge alternative, as long as the disposal does not compromise the integrity of the refuge alternative or affect its operation. The final rule is the same as proposed.

Final paragraph (c)(4), like the proposal, requires that refuge alternatives include first aid supplies. This requirement assures that first aid supplies are available for treating injured miners.

One commenter requested that the Agency specify the nature and quantity of required supplies. Another commenter stated that first aid kits should contain instructions for treating injuries that could be anticipated in the aftermath of an accident and warned that the inclusion of ``anxiety and or sleep inducing drugs'' could present medical issues.

First aid supplies must be adequate to provide for the number of persons injured in an emergency. In an underground mine emergency, MSHA expects that there will be a proportionally higher number of injuries related to lacerations, burns, and fractures resulting from explosions and fires. The refuge alternative must contain first aid supplies to address these injuries, but the final rule does not specify the content of the first aid kit. The final rule is the same as the proposal and is consistent with the safety standards for ERPs in this final rule.

Final paragraph (c)(5), like the proposal, requires that refuge alternatives be stocked with materials, parts, and tools for repair of components. Manufacturers could provide a repair kit with necessary materials and appropriate tools to perform repairs. Materials and tools should include metal repair materials, fiber material, adhesives, sealants, tapes, and general hardware (i.e., screws, bolts, rivets, wire, zippers and clips). Powered tools must be approved as intrinsically safe and permissible. One commenter supported and no commenters opposed the proposal. The final rule is the same as the proposal.

Final paragraph (c)(6), is redesignated and clarified from proposed Sec. 7.506(i). It requires a fire extinguisher that meets the requirements for portable fire extinguishers used in underground coal mines under part 75; and that is appropriate for fires involving the chemicals used for harmful gas removal; and that uses a lowtoxicity extinguishing agent that does not produce a hazardous byproduct when activated. One commenter supported and no commenters opposed the proposal. The final rule clarifies MSHA's intent. MSHA's intent is that the fire extinguisher must protect miners from potentially toxic chemicals in the confined atmosphere of a refuge alternative. The final rule requires that a fire extinguisher meet the requirements of MSHA's existing standards for portable fire extinguishers. It changes the proposed requirement limited to carbon dioxide chemicals to chemicals used for harmful gas removal, and nontoxic extinguishing agent to low toxicity extinguishing agent. The final rule does not include the proposed requirement that the fire extinguisher not produce hazardous byproduct when heated.

Final Sec. 7.504(d)(1), (2), and (3) are substantively the same as the proposal, and require that containers used for storage of refuge alternative components or provisions be airtight, waterproof, and rodentproof; easy to open and close without the use of tools; and conspicuously marked with an expiration date and instructions for use. These requirements assure that the containers' contents will be useable when needed.

One commenter requested clarification of the components that are covered by this provision. Another commenter requested that the final rule only apply to specific items, such as food and water, which are subject to degradation.

The final rule clarifies the proposal by including the term ``or provisions.'' Provisions include items such as supplies, materials, systems, and food and water. Food and water would need to be contained in airtight, waterproof, and rodentproof containers because these provisions are subject to degradation.

Section 7.505 Structural Components

Final Sec. 7.505, like the proposal, addresses structural component requirements for refuge alternatives.

Final paragraph (a)(1) requires that refuge alternatives provide at least 15 square feet of floor space per person, like the proposal, but includes changes in the required cubic feet of volume per person according to the following chart for mining heights:
[[Page 80665]]
Unrestricted volume (cubic Mining height (inches) feet) per person * 36 or less................................ 30
>36<=42.................................. 37.5
>42<=48.................................. 45
>48<=54.................................. 52.5
>54....................................... 60

* Includes an adjustment of 12 inches for clearances.

In addition, the final rule clarifies that the airlock can be included in the space and volume if waste is disposed outside the refuge alternative.

The volume of the refuge alternative is calculated by assuming two factors: (1) 6 inches is necessary to allow for clearance of the refuge alternative to be moved; and (2) the usable interior height of the refuge alternative is reduced by 6 inches for the roof and floor beams. As an example, a 36inch mine height is reduced by 6 inches for clearance and 6 inches for inside beams leaving 24 inches or 2 feet. The 24 inches or 2 feet multiplied by 15 square feet of floor space equals 30 cubic feet of volume per person. Under the final rule, MSHA intends for persons to have this space without being affected by other factors such as stored items.

In the preamble to the proposed rule and in the Agency's opening statements at the public hearings, MSHA requested comments on the proposed requirement of at least 15 square feet of floor space and 60 cubic feet of volume per person, particularly in low mining heights. MSHA received comments in support of and opposed to the proposal.

Some commenters supported 15 square feet

FOR FURTHER INFORMATION CONTACT

Patricia W. Silvey at silvey.patricia@dol.gov (Email), 2026939440 (Voice), or 2026939441 (Fax).