# 73 FR 34140: Refuge Alternatives for Underground Coal Mines

> Federal · Regulations · In force

URL: https://www.frixlaw.com/law-library/statutes/FR_PRORULE_E8-13565

## Section

- **Citation:** 73 FR 34140
- **Heading:** Refuge Alternatives for Underground Coal Mines
- **Jurisdiction:** Federal
- **Kind:** Regulations
- **Status:** In force
- **Text as of:** August 14, 2026
- **Source:** Compiled text
- **Location:** Federal Register / Vol. 73 / 73 FR 34140

## Text

DEPARTMENT OF LABOR Mine Safety and Health Administration 30 CFR Parts 7 and 75 RIN 1219-AB58 Refuge Alternatives for Underground Coal Mines AGENCY:
Mine Safety and Health Administration, Labor.

ACTION:
Proposed rule; notice of public hearings and close of comment period.

SUMMARY:
The Mine Safety and Health Administration (MSHA) is proposing requirements for refuge alternatives in underground coal mines and the training of miners in their use. The proposed rule also includes requirements for testing and approval of refuge alternatives. The proposal would implement section 13 of the Mine Improvement and New Emergency Response (MINER) Act of 2006. Consistent with the MINER Act, it includes MSHA's response to the National Institute for Occupational Safety and Health Report on Refuge Alternatives.

DATES:
All comments must be received by midnight Eastern Standard Time on August 18, 2008. MSHA will hold 4 public hearings on July 29, July 31, August 5, and August 7, 2008. Details about the public hearings are in the SUPPLEMENTARY INFORMATION section of this document.

ADDRESSES:
Comments must be clearly identified with “RIN 1219-AB58” and may be sent by any of the following methods:
(1) Federal e-Rulemaking Portal: http://www.regulations.gov. Follow the instructions for submitting comments.
(2) Electronic mail: zzMSHA-comments@dol.gov. Include “RIN 1219-AB58” in the subject line of the message.
(3) Facsimile: 202-693-9441. Include “RIN 1219-AB58” in the subject line of the message.
(4) Regular Mail: MSHA, Office of Standards, Regulations, and Variances, 1100 Wilson Boulevard, Room 2350, Arlington, Virginia 22209-3939.
tions.gov. Follow the instructions for submitting comments.
(2) Electronic mail: zzMSHA-comments@dol.gov. Include “RIN 1219-AB58” in the subject line of the message.
(3) Facsimile: 202-693-9441. Include “RIN 1219-AB58” in the subject line of the message.
(4) Regular Mail: MSHA, Office of Standards, Regulations, and Variances, 1100 Wilson Boulevard, Room 2350, Arlington, Virginia 22209-3939.
(5) Hand Delivery or Courier: MSHA, Office of Standards, Regulations, and Variances, 1100 Wilson Boulevard, Room 2350, Arlington, Virginia. Sign in at the receptionist's desk on the 21st floor.
Comments can be accessed electronically at http://www.msha.gov under the Rules and Regs link. MSHA will post all comments on the Internet without change, including any personal information provided. Comments may also be reviewed at the Office of Standards, Regulations, and Variances, 1100 Wilson Boulevard, Room 2350, Arlington, Virginia. Sign in at the receptionist's desk on the 21st floor.
MSHA maintains a list that enables subscribers to receive e-mail notification when rulemaking documents are published in the Federal Register . To subscribe, go to http://www.msha.gov/subscriptions/subscribe.aspx.
Information Collection Requirements: Comments concerning the information collection requirements of this proposed rule must be clearly identified with “RIN 1219-AB58” and sent to both the Office of Management and Budget (OMB) and MSHA. Comments to OMB may be sent by mail addressed to the Office of Information and Regulatory Affairs, Office of Management and Budget, New Executive Office Building, 725 17th Street, NW., Washington, DC 20503, Attn: Desk Officer for MSHA. Comments to MSHA may be transmitted either electronically to zzMSHA-Comments@dol.gov, by facsimile to (202) 693-9441, or by regular mail, hand delivery, or courier to MSHA, Office of Standards, Regulations, and Variances, 1100 Wilson Blvd., Room 2350, Arlington, Virginia 22209-3939.
FOR FURTHER INFORMATION CONTACT:
Patricia W
17th Street, NW., Washington, DC 20503, Attn: Desk Officer for MSHA. Comments to MSHA may be transmitted either electronically to zzMSHA-Comments@dol.gov, by facsimile to (202) 693-9441, or by regular mail, hand delivery, or courier to MSHA, Office of Standards, Regulations, and Variances, 1100 Wilson Blvd., Room 2350, Arlington, Virginia 22209-3939.
FOR FURTHER INFORMATION CONTACT:
Patricia W. Silvey at silvey.patricia@dol.gov (E-mail), 202-693-9440 (Voice), or 202-693-9441 (Fax).

SUPPLEMENTARY INFORMATION:
The outline of this proposal is as follows:
I. Introduction A. Rulemaking Background B. Discussion of the Hazard II. Section-by-Section Analysis A. Part 7 Approval B. Part 75 Safety Standards III. Executive Order 12866 A. Population at Risk B. Benefits C. Compliance Costs IV. Feasibility A. Technological Feasibility B. Economic Feasibility V. Regulatory Flexibility Act and Small Business Regulatory Enforcement Fairness Act A. Definition of a Small Mine B. Factual Basis for Certification VI. Paperwork Reduction Act A. Summary B. Procedural Details VII. Other Regulatory Analyses A. The Unfunded Mandates Reform Act of 1995 B. The Treasury and General Government Appropriations Act of 1999: Assessment of Federal Regulations and Policies on Families C. Executive Order 12630: Government Actions and Interference With Constitutionally Protected Property Rights D. Executive Order 12988: Civil Justice Reform E. Executive Order 13045: Protection of Children From Environmental Health Risks and Safety Risks F. Executive Order 13132: Federalism G. Executive Order 13175: Consultation and Coordination With Indian Tribal Governments H. Executive Order 13211: Actions Concerning Regulations That Significantly Affect Energy Supply, Distribution, or Use I. Executive Order 13272: Proper Consideration of Small Entities in Agency Rulemaking Public Hearings
MSHA will hold four public hearings on the proposed rule. These public hearings will begin at 9 a.m
ive Order 13175: Consultation and Coordination With Indian Tribal Governments H. Executive Order 13211: Actions Concerning Regulations That Significantly Affect Energy Supply, Distribution, or Use I. Executive Order 13272: Proper Consideration of Small Entities in Agency Rulemaking Public Hearings
MSHA will hold four public hearings on the proposed rule. These public hearings will begin at 9 a.m. and end after the last speaker speaks, and in any event not later than 5 p.m., on the following dates at the locations indicated:
Date Location Contact information July 29, 2008 Radisson Hotel Salt Lake City Downtown, 215 West South Temple, Salt Lake City, UT 84101 (801) 933-8022. July 31, 2008 Marriott Charleston Town Center, 200 Lee Street East, Charleston, WV 25301 (304) 345-6500. August 5, 2008 Hilton Suites Lexington Green, 245 Lexington Green Circle, Lexington, KY 40503 (859) 271-4000. August 7, 2008 Sheraton Birmingham, 2101 Richard Arrington Jr. Blvd., Birmingham, AL 35203 (205) 324-5000. The hearings will begin with an opening statement from MSHA, followed by an opportunity for members of the public to make oral presentations. Requests to speak at a hearing should be made at least 5 days prior to the hearing date. Requests to speak may be made by telephone (202-693-9440), facsimile (202-693-9441), or mail (MSHA, Office
Any unallocated time at the end of each hearing will be made available to persons making same-day requests to speak. Any unallocated time at the end of each hearing will be made available to persons making same-day requests to speak. Speakers will speak in the order that they sign in at the hearing. At the discretion of the presiding official, the time allocated to each speaker 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. Formal rules of evidence and cross examination will not apply
in the order that they sign in at the hearing. At the discretion of the presiding official, the time allocated to each speaker 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. Formal rules of evidence and cross examination will not apply. The hearing panel may ask questions of speakers. Speakers and other attendees may present written information to the MSHA panel for inclusion in the rulemaking record. MSHA will accept post-hearing written comments and data for the record from any interested party, including those not presenting oral statements, until the close of the comment period. MSHA will make transcripts of the hearings, post them on MSHA's Web site http://www.msha.gov , and include them in the rulemaking record.
I. Introduction
This proposed rule would implement section 13 of the Mine Improvement and New Emergency Response (MINER) Act of 2006. It would require that operators include refuge alternatives in the Emergency Response Plan required by section 2 of the MINER Act. MSHA's objective, consistent with the MINER Act, is to improve the safety of mines and mining. Toward that end, the proposal would improve mine operators' preparedness for mine emergencies and require refuge alternatives underground to protect persons trapped when a life-threatening event occurs that makes escape impossible. Refuge alternatives can also be used to assist miners in escaping from the mine. MSHA developed this proposed rule based on Agency data and experience, NIOSH recommendations, research on available and developing technology, and regulations of several states
cies and require refuge alternatives underground to protect persons trapped when a life-threatening event occurs that makes escape impossible. Refuge alternatives can also be used to assist miners in escaping from the mine. MSHA developed this proposed rule based on Agency data and experience, NIOSH recommendations, research on available and developing technology, and regulations of several states. The proposed rule includes—
• New requirements for testing and approval of refuge alternatives and components of refuge alternatives;
• Requirements for the availability and maintenance of refuge alternatives and communication facilities for refuge alternatives; and
• Requirements for miners to be trained in the location, use, maintenance, and transportation of refuge alternatives.
A. 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. P06-V-10 (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 in approving ERPs. MSHA issued Program Information Bulletin (PIB) No. P07-03 (February 8, 2007) to provide additional guidance to be used in conjunction with the PPL. The PIB represents the quantity of breathable air that would be sufficient to maintain persons for a sustained period of time.
Section 13 of the MINER Act directs NIOSH to conduct research on refuge alternatives and submit a report on the results of the research to the Secretary of Labor, among others
07-03 (February 8, 2007) to provide additional guidance to be used in conjunction with the PPL. The PIB represents the quantity of breathable air that would be sufficient to maintain persons for a sustained period of time.
Section 13 of the MINER Act directs NIOSH to conduct research on refuge alternatives and submit a report on the results of the research to the Secretary of Labor, among others. Section 13 also directs the Secretary of Labor to—
* * * 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 report, including proposed regulatory changes and the reasons for such actions. MSHA has reviewed NIOSH's report and determined that refuge alternatives are practical and will increase the chance for survival for persons trapped in underground coal mines, when integrated into the mine's comprehensive escape and rescue plans.
B. Discussion of the Hazard
MSHA reviewed a number of underground coal mine accident reports in the development of this proposed rule. The Agency discusses the following accidents, which reflect typical emergency conditions, hazards, and issues in underground coal mines.
On March 9, 1976, an explosion occurred at the Scotia Mine in Kentucky. Fifteen miners died from the explosion. Of these fifteen miners, six were found behind a partially built protective structure.
On December 19, 1984, a fire occurred at the Wilberg Mine in Utah. Twenty-eight miners were working on the section when the fire occurred. The intake airway and adjacent belt entry were impassable due to gas and smoke. One miner survived by using an SCSR and crawling on his stomach through the smoke-filled mine. The remaining twenty-seven miners who survived the fire, died while attempting to evacuate the mine
9, 1984, a fire occurred at the Wilberg Mine in Utah. Twenty-eight miners were working on the section when the fire occurred. The intake airway and adjacent belt entry were impassable due to gas and smoke. One miner survived by using an SCSR and crawling on his stomach through the smoke-filled mine. The remaining twenty-seven miners who survived the fire, died while attempting to evacuate the mine.
On July 24, 2002, a nonfatal entrapment accident caused by a water inundation occurred at Quecreek #1 Mine, Black Wolf Coal Company, Inc., located at Quecreek, Somerset County, Pennsylvania. Nine miners had attempted to escape, but were blocked by water. The miners were trapped for over 3 days before all were rescued.
On January 2, 2006, an explosion in which 12 miners were trapped occurred at the Sago Mine, located near Tallmansville, West Virginia. The explosion killed one miner instantly and destroyed seals and filled portions of the mine with toxic levels of carbon monoxide. The victims' attempts to evacuate were unsuccessful and they barricaded themselves on the section. Unfortunately, the barricade was constructed in an area with high concentrations of carbon monoxide. Eleven miners died before they could be rescued and one was rescued although severely injured.
On January 19, 2006, a fire occurred at the belt take-up storage unit of the Aracoma Alma Mine #1, located near Logan, West Virginia, resulting in the deaths of two miners. Miners in the affected area began an evacuation and, after traveling some distance out of the mine, encountered smoke and donned their self-contained self-rescue (SCSRs) devices. The two miners who died had become separated from their crew while attempting to escape.
On May 20, 2006, an explosion occurred at the Kentucky Darby, LLC, Darby Mine No. 1, located near Holmes Mill, Kentucky. The forces from the explosion killed two miners. Four other miners attempted to evacuate and encountered thick smoke
ered smoke and donned their self-contained self-rescue (SCSRs) devices. The two miners who died had become separated from their crew while attempting to escape.
On May 20, 2006, an explosion occurred at the Kentucky Darby, LLC, Darby Mine No. 1, located near Holmes Mill, Kentucky. The forces from the explosion killed two miners. Four other miners attempted to evacuate and encountered thick smoke. At this point they donned their SCSRs and attempted to continue their evacuation. The miners eventually became separated and three died from carbon monoxide poisoning.
Based on the MINER Act, MSHA data and experience, and the NIOSH report, MSHA is proposing regulations that address the approval and use of refuge alternatives in underground coal mines.
II. Section-By-Section Analysis
A. Part 7 Approval
The proposal includes new requirements for approval of refuge alternatives for underground coal mines. The proposal also includes approval of components of refuge alternatives. Under the proposal, manufacturers could apply for approval of a pre-fabricated self-contained refuge alternative or for approval of a refuge alternative component.
MSHA is proposing the approval requirements in part 7 to allow refuge alternatives or components to be tested by applicants or third-parties. MSHA has a 20-year history of administering this program, which has reduced product testing costs and improved approval efficiency. Under the proposal, the applicant, usually the manufacturer, would have to provide the required information and demonstrate that the refuge alternative or component meets the technical requirements and test criteria. Based upon an evaluation of this information, MSHA would issue an approval.
The proposal would: Provide alternatives for satisfying the requirements; provide performance-based approval criteria; and promote innovative new technology
facturer, would have to provide the required information and demonstrate that the refuge alternative or component meets the technical requirements and test criteria. Based upon an evaluation of this information, MSHA would issue an approval.
The proposal would: Provide alternatives for satisfying the requirements; provide performance-based approval criteria; and promote innovative new technology. The proposal addresses requirements for a pre-fabricated self-contained refuge alternative and components for a refuge alternative:
• Structural, which would create an isolated atmosphere and contain the other integrated components.
• Pre-fabricated self-contained rescue alternative.
• Breathable air, which would include the means to supply safe concentrations of oxygen and dilute harmful gases.
• Air-monitoring, which would provide occupants of the refuge alternative with devices to measure the concentrations of oxygen, carbon dioxide, carbon monoxide, methane, and other harmful gases.
• Harmful gas removal, which would provide for removal of harmful gases from the refuge alternative.
The refuge alternative would have to include provisions for sanitation, food, water, and first-aid. These items would have to be approved in the ERP.
The proposed requirements would assure that the refuge alternative could be used safely and effectively in underground coal mines and that the components could be used safely with each other.
All of the existing general provisions of subpart A of part 7 would apply to refuge alternatives. Existing § 7.8 addresses post-approval product audit and requires that, on request the approval-holder make a product available to MSHA for audit at no cost to MSHA, but no more than once a year except for cause. In addition, under existing § 7.8, an audit would be conducted at a mutually agreeable site and time
existing general provisions of subpart A of part 7 would apply to refuge alternatives. Existing § 7.8 addresses post-approval product audit and requires that, on request the approval-holder make a product available to MSHA for audit at no cost to MSHA, but no more than once a year except for cause. In addition, under existing § 7.8, an audit would be conducted at a mutually agreeable site and time. MSHA anticipates that in appropriate instances, the Agency would travel to the manufacturer's site particularly for pre-fabricated self-contained refuge alternatives and components. For refuge alternatives that are not pre-fabricated, i.e. constructed in place or materials pre-positioned, the structure would be approved by the District Manager in the Emergency Response Plan. Consistent with this requirement, the approval-holder must provide a refuge alternative or component to MSHA for audit.
Section 7.501 Purpose and Scope
This proposal would state that the purpose of approved refuge alternatives is to provide a life-sustaining environment for miners trapped underground when escape is impossible. The proposal would also define the scope as applying to underground coal mines. Under the proposal, refuge alternatives could also 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. In its report on refuge alternatives, NIOSH recognized that the “potential for 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.”
Refuge alternatives that states have approved and those that MSHA has accepted in approved ERPs would meet the requirements of this proposed rule
n its report on refuge alternatives, NIOSH recognized that the “potential for 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.”
Refuge alternatives that states have approved and those that MSHA has accepted in approved ERPs would meet the requirements of this proposed rule. When mine operators replace these refuge alternatives or components, the new refuge alternatives or components must meet the requirements of the proposed rule. Based on preliminary discussions with manufacturers, MSHA used the estimated service life of the pre-fabricated self-contained refuge alternative. This would allow refuge alternatives to be used until replaced or 10 years maximum. This would allow refuge components to be used until replaced or 5 years maximum. MSHA solicits comments on the estimated service life of the pre-fabricated self-contained units. Comments should be specific, including alternatives, rationale, and supporting data.
Section 7.502 Definitions
The proposed rule includes several definitions to assist applicants in preparing applications for approval. Because refuge alternatives represent a relatively new technology for underground coal mines, the terminology may not be widely used. MSHA intends that these definitions would facilitate the mining community's understanding of the proposal.
Apparent temperature.
MSHA proposes to define apparent temperature as the combined effects of air movement, heat, and humidity on the human body. 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. The international scientific community generally recognizes a maximum safe apparent temperature of 95° Fahrenheit (F) in confined survival environments, 1 such as a refuge alternative
ement, heat, and humidity on the human body. 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. The international scientific community generally recognizes a maximum safe apparent temperature of 95° Fahrenheit (F) in confined survival environments, 1 such as a refuge alternative. Body heat is the primary heat source in a refuge alternative and the humidity will likely be high in such a sealed environment. The carbon dioxide absorption process also generates heat and humidity. There is currently no permissible air conditioning equipment, which will overcome this problem in underground coal mines.
1 1 R.G. Steadman (1979).
Breathable oxygen.
MSHA proposes to define breathable oxygen as oxygen that is at least 99 percent pure with no harmful contaminants. Acceptable breathable oxygen is frequently supplied from a compressed gas cylinder as U.S. Pharmacopoeia medical oxygen or as aviator breathing oxygen. This definition is consistent with the attachment to MSHA's PIB P07-03: “Methods for Providing Breathable Air.” MSHA solicits comments on the proposed definition. Comments should be specific, including alternatives, rationale, and supporting data.
Flash fire.
MSHA proposes to define flash fire as a fire that rapidly spreads through a diffuse fuel, such as airborne coal dust or methane, without producing damaging pressure. 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
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 1000° to 1900 °F
e, a flash fire can be a rapidly moving flame front from a
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 1000° to 1900 °F.
Noncombustible material.
MSHA proposes to define noncombustible material as material that will not ignite, burn, support combustion, or release flammable vapors when subjected to fire or heat.
Overpressure.
MSHA proposes to define overpressure as the pressure above the background atmospheric pressure. 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 which is 14.7 psi or one atmosphere higher. Explosion pressures are normally expressed as an overpressure beyond standard atmospheric pressure.
Refuge alternative.
MSHA proposes to define refuge alternative as a protected, secure space with an isolated atmosphere and integrated components that create a life-sustaining environment for persons trapped in an underground coal mine.
The proposed rule addresses refuge alternatives that consist of a protective structure, an airlock, an interior space, and components that provide for breathable air, air monitoring, and harmful gas removal. The refuge alternative would also include provisions for sanitation, lighting, communications, food and water, and first aid.
Section 7.503 Application Requirements
Proposed paragraph (a) would require 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
include provisions for sanitation, lighting, communications, food and water, and first aid.
Section 7.503 Application Requirements
Proposed paragraph (a) would require 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.
Paragraph (a)(1) would require the application to contain the refuge alternative or component's make and model number, if applicable. This provision would assist MSHA in identifying specific units or parts from different companies.
Paragraph (a)(2) would require that the application list the refuge alternative or component's parts, including the MSHA approval number for electric-powered equipment; each component's or part's in-mine shelf life, service life, and recommended replacement schedule; and the materials used in each component or part with their MSHA approval number or a statement that the materials are noncombustible. This proposed provision would assure that materials are safe for use in an underground coal mine. The hazardous nature of an underground coal mine requires that sources of ignition be eliminated. MSHA may have approved some equipment as intrinsically safe or permissible that may be used in a refuge alternative component. 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.
Paragraph (a)(3) would require the application to specify the capacity and duration (the number of persons it is designed to maintain and for how long) of the refuge alternative or component on a per-person per-day basis. For example, the application would need to include the specific number of persons and a specific length of time that the refuge alternative or component could support
to heat.
Paragraph (a)(3) would require the application to specify the capacity and duration (the number of persons it is designed to maintain and for how long) of the refuge alternative or component on a per-person per-day basis. For example, the application would need to include the specific number of persons and a specific length of time that the refuge alternative or component could support. The application also would need to contain this same information for food, water, lighting, sanitation, and any other materials that must be provided to assure proper use of the refuge alternative or component. 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.
Paragraph (a)(4) would require the application to specify the length, width, and height of space required for storage of each component. MSHA 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.
Paragraph (b) would require that the application include additional information for the refuge alternative. This specific information is necessary for the applicant or third party to perform an adequate evaluation of the refuge alternative and for MSHA to approve the refuge alternative or component.
Paragraph (b)(1) would require the application to describe the breathable air component, including drawings, air-supply sources, piping, regulators, and controls. This information is necessary for the applicant to demonstrate that all systems are included and in their proper location, to assure proper functioning of this component.
Paragraph (b)(2) would require the application to specify the maximum volume of the refuge alternative, excluding the airlock; the dimensions of usable space provided for each person; and the interior dimensions of the airlock
This information is necessary for the applicant to demonstrate that all systems are included and in their proper location, to assure proper functioning of this component.
Paragraph (b)(2) would require the application to specify the maximum volume of the refuge alternative, excluding the airlock; the dimensions of usable space provided for each person; and the interior dimensions of the airlock. This information is necessary to demonstrate that there is adequate usable space when all systems and components are shown in their respective place.
Paragraph (b)(3) would require the application to specify the maximum allowable positive pressures of the refuge alternative and airlock and describe the means used to limit or control the positive pressure in the refuge alternative and airlock. Information on the refuge alternative and airlock is essential for MSHA to determine whether the atmospheric pressure in the refuge alternative will maintain good air as miners enter and pass through the airlock. The information will be used to demonstrate that the pressure will be adequate for the intended purpose but not excessive, which could create adverse physiological effects for the miners.
Paragraph (b)(4) would require that the application specify the maximum allowable apparent temperature of the interior space of the refuge alternative and airlock and describe the means used to control the apparent temperature in the refuge alternative and airlock. This information provides a basis to determine whether the refuge alternative will protect miners from heat stress. Data show that apparent temperatures greater than 80 °F are generally associated with some discomfort. Medical evidence reveals that values approaching or exceeding 105 °F would be life-threatening, resulting in severe heat exhaustion or possible heatstroke if exposure is prolonged or physical activity high. The degree of heat stress would vary with age, health, and body characteristics
at stress. Data show that apparent temperatures greater than 80 °F are generally associated with some discomfort. Medical evidence reveals that values approaching or exceeding 105 °F would be life-threatening, resulting in severe heat exhaustion or possible heatstroke if exposure is prolonged or physical activity high. The degree of heat stress would vary with age, health, and body characteristics.
Paragraph (b)(5) would require that each application include drawings that show the features of each component and contain sufficient information to document that each component meets the technical requirements of this subpart. Drawings of each component would illustrate the internal configuration of the refuge alternative. Under the proposal, this information
Paragraph (b)(6) would require that the application include essential information or instructions, such as a training manual that contains sufficient detail to train personnel to transport, operate, and maintain the refuge alternative or component. MSHA recognizes that, as a general practice, manufacturers provide users with information necessary for safe and effective use of their products. Under the proposal, the applicant would be required to develop a training manual for each refuge alternative or component.
Paragraph (b)(7) would require a summary of the procedures for constructing and activating refuge alternatives. MSHA recognizes that, as a general practice, manufacturers provide users with information necessary for safe and effective use of their products. This summary information would include all of the steps and procedures to construct and activate a refuge alternative. This information would be used in evaluating the approval and for instruction in the construction and activation of refuge alternatives.
Paragraph (b)(8) would require a summary of the procedures related to using refuge alternatives. This summary information would include steps and procedures for using the refuge alternative during a substantial period of time
and activate a refuge alternative. This information would be used in evaluating the approval and for instruction in the construction and activation of refuge alternatives.
Paragraph (b)(8) would require a summary of the procedures related to using refuge alternatives. This summary information would include steps and procedures for using the refuge alternative during a substantial period of time. This information would be used in evaluating the approval and for instruction in using the refuge alternatives.
Paragraph (b)(9) would require that the application contain the results of inspections, evaluations, calculations, and tests conducted under this subpart. MSHA would use this information to evaluate the effectiveness and compatibility of refuge alternative components. For example, the application would 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.
Paragraph (c) would require that the application for the air-monitoring component include additional information. This information is necessary for the applicant or third party to make an effective evaluation of the component to provide a basis for MSHA approval of the air-monitoring component.
Paragraph (c)(1) would require that the application specify the types of sensors, their operating ranges, the gases measured, and any environmental limitations including the cross-sensitivity of each detector or device to other gases. This information on the air-monitoring component 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
etector or device to other gases. This information on the air-monitoring component 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.
Paragraph (c)(2) would require that the application include the method for operation of each device so that it functions as necessary to test gas concentrations over a 96 hour period. This information will assist MSHA's evaluation of whether the air-monitoring component can sustain persons for 96 hours. The Agency recognizes that different types and combinations of instruments from several manufacturers may be used in an air-monitoring component. MSHA needs to assure that the different components are available and will provide reliable monitoring of breathable air as necessary over the 96-hour period. MSHA believes that a properly designed system would control gas concentrations inside the refuge alternative. The intent of this provision is that detectors would be used to periodically check gas concentrations in the refuge alternative and provide miners with this information.
Paragraph (c)(3) would require that the application include procedures for monitoring and maintaining breathable air in the airlock, before and after purging. Under the proposal, breathable air must be provided in the airlock at all times. However, when miners enter the airlock following an emergency, it will be necessary to monitor and purge the air to remove any contaminants and minimize contamination inside the refuge alternative as miners pass through the airlock into the interior space.
Paragraph (c)(4) would require that the application include instructions for determining the quality of the atmosphere in the airlock and interior of the refuge alternative and a means to maintain breathable air in the airlock
o monitor and purge the air to remove any contaminants and minimize contamination inside the refuge alternative as miners pass through the airlock into the interior space.
Paragraph (c)(4) would require that the application include instructions for determining the quality of the atmosphere in the airlock and interior of the refuge alternative and a means to maintain breathable air in the airlock. The quality of air inside the refuge alternative is vital to sustain trapped miners. The procedures for using the air-monitoring component are essential for MSHA to determine whether the component provides adequate means for trapped miners to verify the quality of the air inside and outside the refuge alternative.
Paragraph (d) would require that the application specify the volume of breathable air available for removing harmful gas, both at start-up and while persons enter or exit through the airlock; and the maximum volume of each gas that the component is designed to remove on a per-miner per-day basis. Information on harmful gas removal is essential for MSHA to determine the ability of the refuge alternative to sustain occupants for 96 hours. The purpose of this component is primarily to remove carbon dioxide exhaled by the occupants. MSHA also intends that this component be capable of removing toxic and irritant gases, fumes, mists, and dusts that may enter the refuge alternative through the airlock.
Paragraph (e) would require that the applicant certify that each component is constructed of suitable materials, is of good quality workmanship, is based on sound engineering principles, is safe for its intended use, and is designed to be compatible with other components in the refuge alternative, within the limitations specified in the approval. This information is needed to assure that the application, test results, and construction quality are complete and accurate
nt is constructed of suitable materials, is of good quality workmanship, is based on sound engineering principles, is safe for its intended use, and is designed to be compatible with other components in the refuge alternative, within the limitations specified in the approval. This information is needed to assure that the application, test results, and construction quality are complete and accurate.
Section 7.504 Refuge Alternatives and Components; General Requirements
Proposed § 7.504 provides general safety and health requirements for refuge alternatives and components.
Paragraph (a)(1) would require refuge alternatives and components to be intrinsically safe for use in an underground coal mine and designed with fire and explosion-proof features for use with an oxygen supply component. This requirement would assure that the refuge alternative or component does not contribute to a secondary fire or explosion.
Paragraph (a)(2) would require that a refuge alternative or component not produce noise levels in excess of 85 dBA in the structure's interior. Noise above this level can be irritating and interferes with communication. Exposure to noise at or above the 85 dBA level could adversely affect hearing. Based on MSHA's knowledge, noise controls such as dampening material are available to control noise levels.
Paragraph (a)(3) would require that the refuge alternative or component not liberate harmful or irritating gases or
Paragraph (a)(4) would require that the refuge alternative or component be designed to be moved safely with devices such as tow bars. MSHA recognizes that refuge alternatives could be a hazard to miners during transport if not properly designed and if miners are not adequately trained. Based on MSHA's experience, inadequate rigging and towing devices could cause accidents to miners. The refuge alternative should be designed with proper connections and devices to eliminate or reduce the use of chains, ropes, and slings
tow bars. MSHA recognizes that refuge alternatives could be a hazard to miners during transport if not properly designed and if miners are not adequately trained. Based on MSHA's experience, inadequate rigging and towing devices could cause accidents to miners. The refuge alternative should be designed with proper connections and devices to eliminate or reduce the use of chains, ropes, and slings. In addition, miners would need training on how to move a refuge alternative to avoid injury.
Paragraph (a)(5) would require that the refuge alternative and components be designed to withstand damage during transport and handling. The proposed rule would require that designs incorporate bumpers, guarding, skids, packing and securing devices, and rigging components. Additionally the components and supplies must be configured, arranged, and stored to minimize shifting, movement, or damage during handling and routine transport. Training would incorporate precautions to prevent damage to the refuge alternatives and components while storing, handling, and transporting the equipment.
Paragraph (b) would require that the apparent inside temperature be controlled to prevent heat stroke. The miners will produce heat within the confined space of the refuge alternative. The chemicals used to remove carbon dioxide also generate heat. Over time, the heat build-up could produce heat stroke. NIOSH stated that—
Apparent temperature is a measure of heat stress, but other indices or standards could be used, such as the wet bulb globe temperature. Regardless of the index selected, the numerical value must be assigned to prevent heat stroke.
Paragraph (b)(1) would require that, when used in accordance with the manufacturer's instructions and defined limitations, the apparent temperature in the fully occupied refuge alternative not exceed 95° Fahrenheit. The 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
nt heat stroke.
Paragraph (b)(1) would require that, when used in accordance with the manufacturer's instructions and defined limitations, the apparent temperature in the fully occupied refuge alternative not exceed 95° Fahrenheit. The 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 is based on physiological studies of evaporative skin cooling for various combinations of ambient temperature and humidity. At higher dew-points, the apparent temperature exceeds the actual temperature and measures the increased physiological heat stress and discomfort associated with higher than comfortable 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 °F are generally associated with some discomfort. Temperatures in excess of 105 °F are considered life-threatening, with severe heat exhaustion or heatstroke possible after prolonged exposure or significant physical activity. There is a general consensus among researchers that the apparent temperature within a confined space occupied by humans should not exceed 95 °F. 2
2 U.S. Department of Defense, National Aviation and Space Administration, Canadian, Australian, and the United Kingdom.
MSHA recognizes that body heat and heat generated by chemical reactions (i.e., CO 2 scrubbing chemicals) are inherent heat-producing 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
mical reactions (i.e., CO 2 scrubbing chemicals) are inherent heat-producing 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.
Paragraph (b)(2) would require that calculations or tests be conducted to determine the maximum apparent temperature in the refuge alternative when used at maximum occupancy and in conjunction with required components calculations or test results. In addition, the proposed rule would require that an application include test results and calculations to demonstrate that the apparent temperature within the refuge alternative would not exceed 95 °F when used in conjunction with required components and fully occupied.
MSHA requests specific comments on the apparent temperature and mitigation of heat stress and heat stroke. Comments should address the generation of heat and the methods for measuring heat stress on persons occupying the refuge alternative. Comments should be specific including alternatives, rationale, safety benefits to miners, technological and economic feasibility, and supporting data.
Paragraph (c) would require that refuge alternatives include a number of auxiliary requirements to enhance the safety and survival of persons in a refuge alternative. These requirements would include a means for communicating with persons outside, lighting, and first aid, and provisions for food, water, and sanitation.
Paragraph (c)(1) would require that refuge alternatives accommodate communications. Paragraphs (c)(1)(i) and (ii) would require that refuge alternative accommodate a telephone or an equivalent two-way communication facility that can be used from inside the refuge alternative, or a two-way wireless system when it is approved in the operator's Emergency Response Plan (ERP)
, water, and sanitation.
Paragraph (c)(1) would require that refuge alternatives accommodate communications. Paragraphs (c)(1)(i) and (ii) would require that refuge alternative accommodate a telephone or an equivalent two-way communication facility that can be used from inside the refuge alternative, or a two-way wireless system when it is approved in the operator's Emergency Response Plan (ERP). Manufacturers would need to provide suitable ports, connections, jacks, and fittings for communication equipment, and ports and connections would need to be designed for electrical permissibility and maintaining air quality (gas tight cable entries) within the refuge alternative.
MSHA requests comments on including a requirement that refuge alternatives be designed with a means to signal rescuers on the surface. This would assure that rescuers on the surface could be contacted if the communications systems become inoperable. This signal would be 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. A signaling device would need to be configured to produce a sound on the roof, ribs, or floor while maintaining the isolated atmosphere. Comments should be specific, including alternatives, rationale, safety benefits to miners, technological and economic feasibility, and supporting data.
MSHA requests comments on including a requirement that the manufacturer design refuge alternatives with a means to signal underground rescuers with a homing device. This would assure that rescuers could detect the trapped miners within the mine. Comments should be specific, including alternatives, rationale, safety benefits to miners, technological and economic feasibility, and supporting data.
Paragraph (c)(2) would require that refuge alternatives include lighting sufficient to perform tasks. Lighting that generates significant heat, or requires continual manual power for light generation, would be unacceptable
miners within the mine. Comments should be specific, including alternatives, rationale, safety benefits to miners, technological and economic feasibility, and supporting data.
Paragraph (c)(2) would require that refuge alternatives include lighting sufficient to perform tasks. Lighting that generates significant heat, or requires continual manual power for light generation, would be unacceptable. Light is essential to allow persons to read instructions, warnings, and gauges; 3 The manufacturer or approval holder would have to measure the number of foot candles provided per miner per day and report this information in the refuge alternative's manual.
3 MIL-STD-1472F, Lighting for bomb shelters, NOTICE 1,05 December 2003.
MSHA requests comments on the types, sources, and magnitude of lighting needed for the proper functioning of a refuge alternative and the needs of the occupants. Comments should be specific, including alternatives, rationale, safety benefits to miners, technological and economic feasibility, and supporting data.
Paragraph (c)(3) would require that refuge alternatives include a means to effectively contain human waste and minimize objectionable odors. Information regarding the sanitation would assure that the manufacturer or approval holder has included an adequate means for containing waste.
The proposed provisions on sanitation would encompass containment and disposal of waste. This provision would also require a means for operation and use, and a means, such as a plastic bag and closed receptacle, to contain the waste to prevent objectionable odors from being detected within the interior space. Provisions should include individually packaged sanitation supplies, including toilet paper and hand sanitizer. The manufacturer or approval holder would have to measure the length, width, and height of the container housing the sanitation component and report this information, together with operating instructions, in the refuge alternative's manual
s from being detected within the interior space. Provisions should include individually packaged sanitation supplies, including toilet paper and hand sanitizer. The manufacturer or approval holder would have to measure the length, width, and height of the container housing the sanitation component and report this information, together with operating instructions, in the refuge alternative's manual.
Paragraph (c)(4) would require that refuge alternatives include first aid supplies to treat injuries. The provision would assure that a sufficient quantity of first aid supplies are available for injured miners.
Paragraph (c)(5) would require that refuge alternatives be stocked with materials, parts, and tools for repairs of components. This requirement would assure that refuge alternative manufacturers provide a repair kit with necessary materials and appropriate tools to perform repairs. This should include adequate tools, metal repair materials, fiber material, adhesives, sealants, tapes, and general hardware (i.e., screws, bolts, rivets, wire, zippers and clips). Powered tools must be intrinsically safe and permissible.
Paragraph (d) would require that containers used for storage of refuge alternative components be airtight, waterproof, and rodent-proof; easy to open and close without the use of tools; and conspicuously marked with an expiration date and instructions for use of the component. This requirement would assure that the containers' contents are useable when needed. Some contents should be individually packaged and stored in containers. For example, food and water should be provided in individual, disposable packages and stored in a container.
Section 7.505 Structural Components
Proposed § 7.505 Addresses the Structural Components Required for Refuge Alternatives
Paragraph (a)(1) would require that refuge alternatives provide a minimum of 15 square feet of usable floor space and a minimum of 60 cubic feet of usable volume per person
le, food and water should be provided in individual, disposable packages and stored in a container.
Section 7.505 Structural Components
Proposed § 7.505 Addresses the Structural Components Required for Refuge Alternatives
Paragraph (a)(1) would require that refuge alternatives provide a minimum of 15 square feet of usable floor space and a minimum of 60 cubic feet of usable volume per person. MSHA believes that these proposed minimums are necessary to provide adequate room for miners using the refuge alternative. Usable space or volume means space or volume without stored items. The space and volume requirements are exclusive of the airlock space and volume. NIOSH design parameters recommended 15 square feet and 85 cubic feet per miner. NIOSH stated that these recommendations were not to be considered absolute.
Under this proposed provision, a space of 6 feet of length and 2.5 feet of width would amount to 15 square feet. If the same area has a height of 4 feet, the miner would be provided with 60 cubic feet of space. For mines with lower heights, the 60 cubic feet of space may need to be attained by increasing the length or floor area.
MSHA solicits comments on these minimum space and volume requirements. Comments should be specific, including alternatives, rationale, safety benefits to miners, technological and economic feasibility, and supporting data.
The area cannot be determined solely by the number of miners that would be using the refuge alternative. Miners would need some free space to operate components, drink, eat, and use the sanitation facilities—and tend to injuries. Additional space may be needed for suspended curtains, as part of a passive system CO 2 removal system. Also larger volumes seem to be more effective at dissipating heat.
Paragraph (a)(2) would require that refuge alternatives include storage space for securing and protecting the components during transport and that permits ready access to components for inspection, maintenance, and activation
. Additional space may be needed for suspended curtains, as part of a passive system CO 2 removal system. Also larger volumes seem to be more effective at dissipating heat.
Paragraph (a)(2) would require that refuge alternatives include storage space for securing and protecting the components during transport and that permits ready access to components for inspection, maintenance, and activation.
The proposed rule is intended to provide adequate storage space in addition to the usable space required for persons occupying the unit. The storage space is required for the supplies in containers. The containers need to be secured to prevent movement during transport. The supplies should be located to provide usable space for miners and to be accessible for inspection while the refuge alternative is stored. The components should be positioned to allow for visual checks for availability, readiness and shelf life dates.
Paragraph (a)(3) would require that refuge alternatives include an airlock that creates a barrier to isolate the interior space from the mine atmosphere, except for a refuge alternative capable of maintaining adequate positive pressure. The intent of this provision is to provide breathable air to miners entering the refuge alternative if the mine atmosphere is contaminated. The miners would need to go into the refuge alternative through an airlock supplied with breathable air. The airlock would minimize the amount of contaminated mine air that could enter the interior space of the refuge alternative. The airlock would need to have positive pressure to prevent the contaminated atmosphere from entering the airlock when the outside door is opened. Conversely when the inside door of the airlock is opened, the air inside the airlock should not readily enter the interior space of the refuge alternative. Pressures need to be different between the interior space, airlock space and mine atmosphere
ive. The airlock would need to have positive pressure to prevent the contaminated atmosphere from entering the airlock when the outside door is opened. Conversely when the inside door of the airlock is opened, the air inside the airlock should not readily enter the interior space of the refuge alternative. Pressures need to be different between the interior space, airlock space and mine atmosphere. Pressures need to be incrementally higher in the interior space as compared to the airlock and the airlock pressure needs to be higher than the mine atmosphere. Miners will pass through the airlock via airtight doors into the interior space.
The proposed rule includes an exception for an airlock if the refuge alternative is capable of maintaining adequate positive pressure. The positive pressure would prevent outside air from contaminating the refuge alternative, therefore an airlock would not be necessary.
Paragraph (a)(3)(i) would require that the airlock be designed to be used multiple times to accommodate the structure's maximum occupancy. This provision would assure access for the number of persons for which the refuge alternative is designed.
Paragraph (a)(3)(ii) would require that the airlock be configured to accommodate a stretcher without compromising the airlock's function. Following a mine accident, miners that would use the refuge alternative may be injured and transported on a stretcher. The airlock would need to be an adequate length to accommodate the stretcher (with injured miner) in the airlock with the outside door closed (to allow the interior door to be opened for access to the interior space).
Paragraph (a)(4) would require that refuge alternatives be designed and constructed to withstand 15 pounds per square inch (psi) overpressure for 0.2 seconds prior to activation. Proposed paragraph (a)(5) would require that refuge alternatives be designed and constructed to withstand exposure to a flash fire of 300 °Fahrenheit for 3 seconds prior to activation
for access to the interior space).
Paragraph (a)(4) would require that refuge alternatives be designed and constructed to withstand 15 pounds per square inch (psi) overpressure for 0.2 seconds prior to activation. Proposed paragraph (a)(5) would require that refuge alternatives be designed and constructed to withstand exposure to a flash fire of 300 °Fahrenheit for 3 seconds prior to activation.
Paragraphs (a)(4) and (a)(5) would assure that the refuge alternative would be able to withstand an initial explosion and fire. These provisions would also assure that the components are not damaged and are able to function as intended.
Paragraph (a)(6) would require that refuge alternatives be constructed with materials that are noncombustible or MSHA-approved flame-resistant. MSHA tests for flame resistance of brattice cloth under 30 CFR 7.27 could be used to determine the flame resistance of noncombustible materials in refuge alternatives. Materials under this provision could include, but would not be limited to inflatable stoppings, inflatable shelters, and any materials providing a barrier used to protect the inside atmosphere from the hazardous outside atmosphere. Materials are generally tested for noncombustibility under ASTM E 136 “Standard Test Method for Behavior of Materials in a Vertical Tube Furnace at 750 Degrees C” (2004), although a similar ISO test, “ISO 1182:2002” also exists.
Paragraph (a)(7) would require that refuge alternatives be constructed from reinforced material that has sufficient durability to withstand routine handling and resist puncture and tearing during activation and use. Refuge alternatives need to be capable of withstanding the harsh mining environment and require materials to withstand abrasion, tears and punctures during handling and activation. This especially applies to inflatable-type stoppings and tent refuge alternatives. These materials must be made to isolate areas without compromising the interior atmosphere of the refuge alternative
activation and use. Refuge alternatives need to be capable of withstanding the harsh mining environment and require materials to withstand abrasion, tears and punctures during handling and activation. This especially applies to inflatable-type stoppings and tent refuge alternatives. These materials must be made to isolate areas without compromising the interior atmosphere of the refuge alternative.
Paragraph (a)(8) would require that refuge alternatives be guarded or reinforced to prevent damage that would hinder activation, entry, or use. This paragraph would assure the refuge alternative design incorporates protective features to protect the integrity of the barrier and operation of doors, inflatable extensions of the refuge alternative, or any other functions necessary to use the refuge alternative.
Paragraph (a)(9) would require that refuge alternatives be designed to permit measurement of outside gas concentrations without exiting the structure or allowing entry of the outside atmosphere. Miners would need to conduct gas monitoring of the atmosphere outside of the isolated interior space to monitor harmful gas levels outside the refuge alternative when there is a lack of communication with rescuers and the occupants are considering whether evacuation is a viable option. To assure the safety of the miners, the design should incorporate methods or equipment that can monitor outside of the interior space without contamination.
Proposed § 7.505(b) would address tests for the structural components required for refuge alternatives.
Paragraph (b)(1) would require that tests be conducted to determine or demonstrate that the refuge alternative can be constructed, activated and used as intended. Under this provision, trained persons would need to be able to fully activate the structure, without the use of tools, within 10 minutes of reaching the refuge alternative.
This provision would assure that miners can use the refuge alternative upon reaching it
quire that tests be conducted to determine or demonstrate that the refuge alternative can be constructed, activated and used as intended. Under this provision, trained persons would need to be able to fully activate the structure, without the use of tools, within 10 minutes of reaching the refuge alternative.
This provision would assure that miners can use the refuge alternative upon reaching it. Following an accident, the first actions of the miners are to attempt to evacuate wearing SCSRs. In a worst-case scenario, only one SCSR may be available to provide 60 minutes of breathable air. The first 30 minutes would enable the miner to attempt to evacuate and return to the refuge alternative if escape is impossible. If the miner cannot escape, and returns to a refuge alternative, the miner would have 10 minutes to establish a barrier between the interior and exterior atmospheres. The remaining 20 minutes of breathable air provided by the SCSR will allow refuge alternative purging to establish a breathable air atmosphere. It is expected that the testing under this paragraph would be conducted using simulated real-life situations and conditions, such as smoke, heat, humidity and darkness using SCSRs.
Paragraph (b)(2) would test that an overpressure of 15 psi applied to the pre-activated refuge alternative structure for 0.2 seconds would not allow gases to pass through the barrier separating the interior and exterior atmospheres. Paragraph (b)(3) would test that a flash fire of 300° Fahrenheit for 3 seconds would not allow gases to pass from the outside to the inside of the structure.
Paragraphs (b)(2) and (b)(3) would assure that the refuge alternative is tested to verify that it will withstand an initial explosion and fire. It would also assure the structure and components are intact following a fire or explosion. The testing should demonstrate that the integrity of the barrier and operation of doors is maintained
ses to pass from the outside to the inside of the structure.
Paragraphs (b)(2) and (b)(3) would assure that the refuge alternative is tested to verify that it will withstand an initial explosion and fire. It would also assure the structure and components are intact following a fire or explosion. The testing should demonstrate that the integrity of the barrier and operation of doors is maintained.
MSHA tests for flame resistance of brattice cloth at 30 CFR 7.27 could be used to determine the flame resistance of noncombustible materials in refuge alternatives. Materials under this provision could include, but would not be limited to inflatable stoppings, inflatable shelters, and any materials providing a barrier used to protect the inside atmosphere from the hazardous outside atmosphere. Materials are generally tested for noncombustibility using ASTM E 136 “Standard Test Method for Behavior of Materials in a Vertical Tube Furnace at 750 Degrees C” (2004), although a similar ISO test, “ISO 1182:2002” also exists.
Paragraph (b)(4) would test that the expected overpressure forces do not prevent the stored components from operating. Paragraph (b)(5) would test that a flash fire does not prevent the stored components from operating. Paragraphs (b)(4) and (b)(5) would assure that refuge alternatives are tested to demonstrate that they will withstand an initial explosion and fire. Additionally, the test should assure that an isolated atmosphere is provided for the miners and the components are not damaged and are able to function as intended.
Paragraph (b)(6) would require testing to demonstrate that each structure resists puncture and tearing when tested in accordance with ASTM D2582-07 “Standard Test Method for Puncture-Propagation Tear Resistance of Plastic Film and Thin Sheeting.” This provision will test the capability of material used to construct the refuge alternative
ents are not damaged and are able to function as intended.
Paragraph (b)(6) would require testing to demonstrate that each structure resists puncture and tearing when tested in accordance with ASTM D2582-07 “Standard Test Method for Puncture-Propagation Tear Resistance of Plastic Film and Thin Sheeting.” This provision will test the capability of material used to construct the refuge alternative. The material must withstand the harsh mining environment and abrasion, tears, and punctures during handling, transportation and activation. This especially applies to inflatable-type stoppings and tent refuge alternatives. These materials must be made to maintain barriers without compromising the atmosphere established on the interior of the refuge alternative.
Paragraph (b)(7) would require that each reasonably anticipated repair can be completed within 10 minutes of opening the storage space for repair
Paragraph (b)(8) would require that nonmetallic materials used to construct the refuge alternative, not release harmful gases or noticeable odors before or after the flash fire test. The test would determine the identity and concentrations of gases released. This provision would require a test of the material used to construct the refuge alternative to assure that the materials do not emit noticeable odors that may sicken the miners occupying the refuge alternative. The testing should include provisions and instruments for detecting any released gases. Materials (i.e., paints, plastics, fiber, etc.) used in the manufacturing of the refuge alternative should not release harmful fumes, vapors, or gases.
Proposed § 7.505(c) addresses refuge alternatives that use pressurized air to activate the structure or maintain its shape.
Paragraph (c)(1) would require a pressure regulator or other means to prevent over-pressurization of structures that use pressurized air to activate the structure or maintain its shape
facturing of the refuge alternative should not release harmful fumes, vapors, or gases.
Proposed § 7.505(c) addresses refuge alternatives that use pressurized air to activate the structure or maintain its shape.
Paragraph (c)(1) would require a pressure regulator or other means to prevent over-pressurization of structures that use pressurized air to activate the structure or maintain its shape. Over-pressurization of the interior space or airlock space would be detrimental to the safety of the miners. The regulator should be designed to assure that proper relief of overpressure can be accomplished.
Paragraph (c)(2) would require inclusion of a means to repair and repressurize the structure in case of failure of the structure or loss of air pressure. If the inflatable-type structure is damaged or leaks, it will need repair and additional compressed air to establish the pressure and volume of air that was lost.
Proposed § 7.505(d)(1) would require that refuge alternatives be designed such that pre-shift examination of the components critical for activation can be conducted without entering the structure. Paragraph (d)(2) would require that a refuge alternative be designed to provide a means to indicate unauthorized entry or tampering. Paragraphs (d)(1) and (d)(2) would assure that the refuge alternative is designed to allow for all necessary inspections. The gauges and controls for critical components, such as compressed air and oxygen, should be easy to observe to determine the readiness of those components.
Section 7.506 Breathable Air Components
Paragraph (a) would require that breathable air be supplied by compressed air cylinders, compressed breathable-oxygen cylinders, fans installed on the surface or compressors installed on the surface. Only uncontaminated breathable air is allowed to be supplied to the refuge alternative.
Maintaining breathable air inside the refuge alternative is vital to sustain persons trapped underground
nts
Paragraph (a) would require that breathable air be supplied by compressed air cylinders, compressed breathable-oxygen cylinders, fans installed on the surface or compressors installed on the surface. Only uncontaminated breathable air is allowed to be supplied to the refuge alternative.
Maintaining breathable air inside the refuge alternative is vital to sustain persons trapped underground. Currently MSHA will accept compressed air cylinders and compressed breathable-oxygen cylinders as a means to supply breathable air in underground coal mines. MSHA will also accept fans or compressors installed on the surface as a means to supply breathable air in these mines. The proposed rule addresses MSHA's need to evaluate whether breathable air components will meet the requirement for sustaining persons for 96 hours in a refuge alternative. Provisions regarding the proper use of approved breathable air components are important for MSHA to use in determining that a component will provide adequate air inside the refuge alternative.
The Agency recognizes that different types and combinations of breathable air components from several manufacturers may be used to provide breathable air for refuge alternatives. MSHA needs to assure that these components and combination of components are reliable and ready to use for maintaining persons as necessary over the 96-hour period.
Paragraph (b) would require that mechanisms be provided and procedures be followed within the refuge alternative such that (1) breathable air sustain each person for 96 hours; (2) the oxygen concentration be maintained at levels between 18.5 and 23 percent; and (3) the average carbon dioxide concentration be maintained at 1.0 percent or less, with excursions not to exceed 2.5 percent.
Paragraph (b)(1) addresses MSHA's need to evaluate the effectiveness and compatibility of the breathable air components to assure that the supply of breathable air is sufficient to sustain persons occupying the refuge alternative for 96 hours
ween 18.5 and 23 percent; and (3) the average carbon dioxide concentration be maintained at 1.0 percent or less, with excursions not to exceed 2.5 percent.
Paragraph (b)(1) addresses MSHA's need to evaluate the effectiveness and compatibility of the breathable air components to assure that the supply of breathable air is sufficient to sustain persons occupying the refuge alternative for 96 hours. In MSHA's February 8, 2007, Program Information Bulletin No. P07-03, (PIB P07-03), MSHA addressed that the Agency considered 96 hours to be necessary. MSHA concluded that a 96-hour supply was warranted, and accordingly, the Agency is proposing 96 hours as a time that breathable air would need to be provided. MSHA solicits comments on the proposed 96-hour supply of breathable air. Comments should be specific, including alternatives, rationale, safety benefits to miners, technological and economic feasibility, and supporting data.
In arriving at this 96-hour minimum, MSHA reviewed recent and historical data on entrapments. While it is clear that refuge alternatives can save the lives of trapped persons, it was not clear how long refuge alternatives should be capable of sustaining miners. The depth of the mine, the geology of the overburden, and the terrain above the mine significantly affects rescue activities.
Paragraph (b)(2) would require that mechanisms be provided and procedures be followed within the refuge alternative such that the oxygen concentration be maintained at levels between 18.5 and 23 percent. In this subpart, MSHA is defining breathable oxygen as oxygen that is at least 99 percent pure with no harmful contaminants. Acceptable breathable oxygen is frequently supplied from a compressed gas cylinder as U.S. Pharmacopoeia medical oxygen or as aviator breathing oxygen. In addition, consistent with NIOSH's recommendation, the Agency proposes that breathable air contain an oxygen concentration between 18.5 and 23 percent
ning breathable oxygen as oxygen that is at least 99 percent pure with no harmful contaminants. Acceptable breathable oxygen is frequently supplied from a compressed gas cylinder as U.S. Pharmacopoeia medical oxygen or as aviator breathing oxygen. In addition, consistent with NIOSH's recommendation, the Agency proposes that breathable air contain an oxygen concentration between 18.5 and 23 percent.
Paragraph (b)(3) would require that the average carbon dioxide concentration be maintained at 1.0 percent or less, with excursions not to exceed 2.5 percent. In this subpart, MSHA proposes that breathable air contain no harmful quantities of asphyxiant, irritant, or toxic gases, fumes, mists, or dusts. This is consistent with NIOSH's recommendation. The provision proposes that the carbon dioxide concentration not exceed a 1.0 percent time weighted average over the rated duration of the refuge alternative with excursions not to exceed 2.5 percent.
MSHA is assuming that breathing rates for miners who have reached refuge alternatives would consist of activity levels of 4/5 at rest and 1/5 moderate activity. Therefore, using the respiratory quotient, which is the ratio of CO 2 that expelled to O 2 consumed, the average carbon dioxide generation is 1.08 cubic feet per hour per person. These breathing rates were based upon the U.S. Bureau of Mines Foster Miller Report of 1983, “Development of
The Agency recognizes that in an enclosed space, miners may die from the effects of CO 2 rather than the effects of O 2 deficiency. In PIB P07-03, MSHA demonstrated the rate at which a person would overexpose from carbon dioxide if carbon dioxide were not removed from the environment. MSHA used air supply calculations and activity levels based upon information provided in the Foster Miller report. The Agency used a hypothetical sealed enclosed space with a volume of 1,800 cubic feet (20 feet long, 18 feet wide and 5 feet high) that contained one person
trated the rate at which a person would overexpose from carbon dioxide if carbon dioxide were not removed from the environment. MSHA used air supply calculations and activity levels based upon information provided in the Foster Miller report. The Agency used a hypothetical sealed enclosed space with a volume of 1,800 cubic feet (20 feet long, 18 feet wide and 5 feet high) that contained one person. The initial air quality was assumed to be 19.5% O 2 , and 0.03% CO 2 , and the breathing rate ( 4/5 at rest and 1/5 moderate activity) for oxygen inhaled is 0.022 cubic feet per minute per person.
For this example, MSHA found that one miner could be maintained 49.5 hours in an enclosed space with 1,800 cubic feet and initial air quality of 19.5% O 2 , and 0.03% CO 2 . This equates to 1.65 minutes per cubic foot of enclosed space (volume). Correspondingly, 10 miners could be maintained in a 1,800 cubic foot space for 4.95 hours before the CO 2 concentration reached the defined unacceptable level. In addition, 10 miners in the above defined 1,800 cubic feet volume would reach 10% CO 2 and resulting unconsciousness in approximately 16.6 hours. Unacceptable level for CO 2 would be 3% based on Peele Mining Engineers' Handbook and current MSHA Short Term Exposure Limits.
Paragraph (c) would require that breathable air supplied by compressed air from cylinders, fans, or compressors provide a minimum flow rate of 12.5 cubic feet per minute of breathable air for each miner. MSHA proposes to use 12.5 cubic feet per minute of breathable air as a required volume for each miner based on the amount of air needed for respiration and dilution of CO 2 and other harmful gases. In addition, the 12.5 cubic feet per minute flow rate would assure positive pressure to prevent contamination from the mine atmosphere. A maximum positive relief valve would need to be located in the refuge alternative. MSHA requests comments regarding the flow rate
r as a required volume for each miner based on the amount of air needed for respiration and dilution of CO 2 and other harmful gases. In addition, the 12.5 cubic feet per minute flow rate would assure positive pressure to prevent contamination from the mine atmosphere. A maximum positive relief valve would need to be located in the refuge alternative. MSHA requests comments regarding the flow rate. Comments should be specific including alternatives, rationale, safety benefits to miners, technological and economic feasibility, and supporting data.
MSHA considered the enclosed space as similar to a loose-hood respirator using supplied air. Flair Corporation Bulletin 270 revision H (4-01) indicates that OSHA requires a supply air of 6 to 15 cfm (360 to 900 cfm) for supplied air hoods (continuous flow supplied air respirators) to purge accumulated carbon dioxide. The 12.5 cfm per person fell within this range. Engineering handbooks recommend ventilation rates in the range 10-15 cfm of fresh air per person for offices with 12.5 cfm per person being the midpoint of this range. MSHA believes that these quantities are conservative. However, they are design parameters for a life support system, which demands a more cautious approach. In addition, compressor wear reduces performance and the system will become less efficient with age.
The Agency considers that the use of compressed air cylinders as the sole means of providing breathable air may be impractical and encourages mine operators to consider other options. As MSHA pointed out in PIB P07-03, a fan or equivalent method should be used to force fresh air into the hole with enough positive pressure to overcome total mine pressure to deliver sufficient quantities of breathable air. Compressor air intakes should be installed and maintained to assure that only clean, uncontaminated air enters the compressors. Mines should assure compressors have the capacity to deliver the required volume of air at the point of expected usage
e used to force fresh air into the hole with enough positive pressure to overcome total mine pressure to deliver sufficient quantities of breathable air. Compressor air intakes should be installed and maintained to assure that only clean, uncontaminated air enters the compressors. Mines should assure compressors have the capacity to deliver the required volume of air at the point of expected usage.
Paragraph (c)(1) would require that compressed air from cylinders, fans or compressors provide a minimum flow rate of 12.5 cubic feet per minute of breathable air for each miner. Fans or compressors would be required to (i) be equipped with a carbon monoxide detector located at the surface that automatically provides a visual and audible alarm if carbon monoxide in supplied air exceeds 10 ppm; (ii) provide in-line air-purifying sorbent beds and filters or other equivalent means to assure the breathing air quality and prevent condensation; (iii) include maintenance instructions that provide specifications for periodic replacement or refurbishment of sorbent beds and filters or alternate means; (iv) provide an automatic means to assure that the maximum allowable positive pressure is not exceeded in the refuge alternative; (v) include warnings to assure that only uncontaminated breathable air is supplied to the refuge alternative; (vi) include air lines to supply breathable air from the fan or compressor to the refuge alternative; and (vii) assure that harmful or explosive gases, water, and other materials cannot enter the breathable air. In addition, the proposal would require that air lines be capable of preventing or removing water accumulation, and be designed and protected to prevent damage during normal mining operations, a flash fire of 300° F for 3 seconds, a pressure wave of 15 psi overpressure for 0.2 seconds, and ground failure.
In PIB P07-03, MSHA provided a number of recommendations regarding hazards stemming from the use of compressors to provide breathable air underground
capable of preventing or removing water accumulation, and be designed and protected to prevent damage during normal mining operations, a flash fire of 300° F for 3 seconds, a pressure wave of 15 psi overpressure for 0.2 seconds, and ground failure.
In PIB P07-03, MSHA provided a number of recommendations regarding hazards stemming from the use of compressors to provide breathable air underground. The Agency also acknowledges that these recommendations would apply to the use of fans used for the same purpose. As such, MSHA recommended that compressor air intakes should be installed to assure that only clean, uncontaminated air enters the compressors. Care should be exercised when using compressors in the vicinity of other equipment having gas or diesel engines. Gas engines emit carbon monoxide (toxic fumes) and diesel engines emit sulfur dioxide (noxious fumes) and nitrogen oxides. Compressors requiring oil can generate carbon monoxide (CO) internally which can be supplied inadvertently to miners. Oil-type compressors could be used; however, the air quality must be sampled and/or controlled using CO filtration. Oil-less compressors do not generate carbon monoxide; thus, no CO filtering is required.
Paragraph (c)(1)(i) would require carbon monoxide detectors for compressors or fans at the surface that automatically provide a visual and audible alarm if carbon monoxide in supplied air exceeds 10 ppm because compressors powered by gas engines emit carbon monoxide. Through the use of detectors at the surface, this provision is intended to assure that harmful levels of carbon monoxide would not be transferred into the refuge alternative from this equipment. MSHA is proposing to use the same early warning level for carbon monoxide in compressor supplied breathable air as established by OSHA, which will maintain uniformity in requirements for the use of such specialized equipment. MSHA believes warning operators when the CO level exceeds 10 ppm will help maintain safe breathable air in the refuge alternative
the refuge alternative from this equipment. MSHA is proposing to use the same early warning level for carbon monoxide in compressor supplied breathable air as established by OSHA, which will maintain uniformity in requirements for the use of such specialized equipment. MSHA believes warning operators when the CO level exceeds 10 ppm will help maintain safe breathable air in the refuge alternative. MSHA solicits comments on this provision including alternatives.
Paragraph (c)(1)(ii) would require in-line air-purifying sorbent beds and filters or other equivalent means to assure the breathing air quality and prevent condensation. Sorbent beds and filters would help assure that the air quality is maintained and condensation is prevented.
Paragraph (c)(1)(iii) would require maintenance instructions that provide specifications for periodic replacement or refurbishment of sorbent beds and filters or alternate means. Proper
Paragraph (c)(1)(iv) would require that fans or compressors provide positive pressure and an automatic means to assure that the pressure is relieved in the refuge alternative at 0.25 psi above mine atmospheric pressure. MSHA believes that positive pressure to exceed total mine pressure will prevent contamination and allow sufficient quantities of breathable air. The pressure should be adequate for the intended purpose, but not excessive where it creates adverse physiological effects for the miners. An automatic means, such as a relief valve set at 0.25 psi, should be provided to assure that the refuge alternative is not over-pressurized if breathable air is being supplied through a borehole or other means. The Foster Miller report specifies a minimum of 5 inches of water gage overpressure in the refuge alternative which is equivalent to approximately 0.18 psi. Currently, most manufactured refuge alternatives have relief valves set at 0.25 psi. Having too much pressure differential would make opening doors difficult for miners entering the refuge alternative
upplied through a borehole or other means. The Foster Miller report specifies a minimum of 5 inches of water gage overpressure in the refuge alternative which is equivalent to approximately 0.18 psi. Currently, most manufactured refuge alternatives have relief valves set at 0.25 psi. Having too much pressure differential would make opening doors difficult for miners entering the refuge alternative. MSHA requests comments on the proposed setting for pressure relief and whether a higher pressure relief should be required. Comments should be specific including alternatives, rationale, safety benefits to miners, technological and economic feasibility, and supporting data.
Paragraph (c)(1)(v) would require warnings to assure that only uncontaminated breathable air is supplied to the refuge alternative. This provision is intended to assure that only clean, uncontaminated air enters the compressors. Care should be exercised when using compressors or fans in the vicinity of other equipment having gas or diesel engines.
Paragraph (c)(1)(vi) would require that fans or compressors supplying breathable air underground include air lines to supply the air to the refuge alternative, that (A) air lines be capable of preventing or removing water accumulation, and that (B) air lines be designed and protected to prevent damage during normal mining operations, a flash fire of 300 °F for 3 seconds, a pressure wave of 15 psi overpressure for 0.2 seconds, and ground failure.
Proposed paragraph (c)(1)(vi)(A) is intended to prevent accumulation of water, which could affect the quantity and quality of breathable air provided underground. Moisture-laden air should not be pumped into the area where miners are trapped. If this moisture is not removed water could accumulate in the refuge alternative. All air supply systems must provide a means of preventing and removing the accumulation of water. MSHA anticipates air dryers with drain valves will be used
ich could affect the quantity and quality of breathable air provided underground. Moisture-laden air should not be pumped into the area where miners are trapped. If this moisture is not removed water could accumulate in the refuge alternative. All air supply systems must provide a means of preventing and removing the accumulation of water. MSHA anticipates air dryers with drain valves will be used. Air lines or pipes that are pre-installed must also be capped to prevent the entry of rain or moisture-laden air. If horizontal runs of air lines or pipes are used, they must be provided with a means to automatically drain any water accumulation.
Proposed paragraph (c)(1)(vi)(B) is intended to provide protection for lines that come from boreholes or air lines from the surface that are extended underground to a refuge alternative. This protection could consist of burying pipes by trenching deep enough to protect the pipes from mine traffic, explosions, ground movement or equipment damage.
Paragraph (c)(1)(vii) would assure that harmful or explosive gases, water, and other materials cannot enter the breathable air. When connecting equipment to boreholes that enter the mine, precautions must be taken to prevent explosive or harmful gases from entering the equipment supplying the breathable air. Harmful gases could contaminate filters or other components or collect in the equipment and affect the quality of the air being supplied to the trapped miners.
Paragraph (c)(2) would require redundant fans or compressors and power sources to permit prompt reactivation of equipment in the event of failure. It is crucial to maintain a continuous supply of breathable air to persons trapped underground and MSHA believes that redundant systems would assure that the supply is maintained in the event of failure of one of these systems
d to the trapped miners.
Paragraph (c)(2) would require redundant fans or compressors and power sources to permit prompt reactivation of equipment in the event of failure. It is crucial to maintain a continuous supply of breathable air to persons trapped underground and MSHA believes that redundant systems would assure that the supply is maintained in the event of failure of one of these systems.
Paragraph (d) would require that compressed, breathable oxygen (1) include instructions for activation and operation; (2) provide oxygen at a minimum flow rate of 1.32 cubic feet per hour per miner; (3) include a means to readily regulate the pressure and volume of the compressed oxygen; (4) include an independent regulator as a backup in case of failure; and (5) be used only with regulators, piping, and other equipment that is certified and maintained to prevent ignition or combustion.
Paragraph (d)(1) would require that compressed, breathable oxygen include instructions for activation and operation. This information will assure that mine operators have the proper information to correctly perform the tasks involving activating compressed oxygen cylinders. MSHA believes that failure to properly perform these tasks may imperil the lives of the miners within the refuge alternative. Instructions could include such items as checking for loose connections, leaking gas sounds, damage to hoses along their lengths or at their fittings, and broken gauges. The instructions would also help to assure that tanks are secured and pressure regulators are properly set and that wrenches and pliers will be in proper working order. Safe Use of Oxygen and Oxygen Systems: Guidelines for Oxygen System Design, Materials Selection, Operations, Storage, and Transportation, ASTM Stock No.: MNL 36.
Paragraph (d)(2) would require that compressed, breathable oxygen provides oxygen at a minimum flow rate of 1.32 cubic feet per hour per miner
ure regulators are properly set and that wrenches and pliers will be in proper working order. Safe Use of Oxygen and Oxygen Systems: Guidelines for Oxygen System Design, Materials Selection, Operations, Storage, and Transportation, ASTM Stock No.: MNL 36.
Paragraph (d)(2) would require that compressed, breathable oxygen provides oxygen at a minimum flow rate of 1.32 cubic feet per hour per miner. MSHA is assuming that breathing rates for miners who are using a refuge alternative would reflect activity levels of 4/5 at rest and 1/5 moderate activity. Oxygen consumption at this assumed breathing rate would be 1.32 cubic feet per hour per person (0.022 cubic feet per minute per person). These oxygen consumption rates were based upon the U.S. Bureau of Mines Foster Miller Report of 1983, “Development of Guidelines for Rescue Chambers,” Volume I.
Paragraph (d)(3) would require that compressed, breathable oxygen provide a means to readily regulate the pressure and volume of the compressed oxygen. Regulating is necessary to assure that oxygen levels remain within the recommended values. In addition, all oxygen valves should be opened slowly to prevent the oxygen from heating.
Paragraph (d)(4) would require that compressed, breathable oxygen include an independent regulator as a backup in case of failure. It is crucial to maintain a continuous supply of breathable air to persons trapped underground. MSHA believes that redundant regulators would assure that the miners are maintained in the event of failure of one of these regulators. MSHA expects redundant oxygen control valves and regulators will be provided to assure continual availability of breathable oxygen. This provision is meant to assure that pre-connected valves and regulators are available. This will assure that miners will always have breathable air available in case of component failures
the miners are maintained in the event of failure of one of these regulators. MSHA expects redundant oxygen control valves and regulators will be provided to assure continual availability of breathable oxygen. This provision is meant to assure that pre-connected valves and regulators are available. This will assure that miners will always have breathable air available in case of component failures.
Paragraph (d)(5) would require that compressed, breathable oxygen be used only with regulators, piping, and other equipment that is certified and maintained to prevent ignition or combustion. Components such as
Paragraph (e) would require that carbon dioxide removal components (1) include instructions for activation and operation; (2) be used with breathable air cylinders or oxygen cylinders; (3) remove carbon dioxide at a rate of 1.08 cubic feet per hour per miner; (4) be contained to prevent contact with the chemicals and the release of airborne particles; (5) be provided and packaged with all necessary means to expedite use, such as hangers, racks, and clips; and (6) be stored in containers that are conspicuously marked with instructions for disposal of used chemicals.
Paragraph (e)(1) would require that carbon dioxide removal components include instruction for activation and operation. MSHA needs this information to assure that mine operators have the proper information to correctly perform tasks involving activating carbon dioxide removal components. Carbon dioxide is a natural asphyxiant produced through human respiration. To prevent the accumulation of harmful concentrations of carbon dioxide, scrubbing systems have been developed to chemically absorb the carbon dioxide. When entering a refuge alternative, miners would have to perform tasks to activate the carbon dioxide removal components. The miners would have to purge the atmosphere (in some cases), turn on the breathable air and maintain a viable atmosphere
on. To prevent the accumulation of harmful concentrations of carbon dioxide, scrubbing systems have been developed to chemically absorb the carbon dioxide. When entering a refuge alternative, miners would have to perform tasks to activate the carbon dioxide removal components. The miners would have to purge the atmosphere (in some cases), turn on the breathable air and maintain a viable atmosphere. Depending on the type of CO 2 removal system, instructions could include activation scheduling and proper handling of these materials. MSHA believes that failure to properly perform these tasks may imperil the lives of the miners within the refuge alternative.
Paragraph (e)(2) would require that carbon dioxide removal components be used with breathable air cylinders or oxygen cylinders. MSHA needs to assure that carbon dioxide removal components are compatible with the overall system for providing breathable air.
Paragraph (e)(3) would require that carbon dioxide removal components remove carbon dioxide at a rate of 1.08 cubic feet per hour per miner. MSHA is assuming that breathing rates for miners who have reached refuge alternatives would reflect activity levels of 4/5 at rest and 1/5 moderate activity. Therefore, using the respiratory quotient, which is the ratio of CO 2 expelled to O 2 consumed, the average carbon dioxide generation is 1.08 cubic feet per hour per person. These breathing rates were based upon the Foster Miller report.
Paragraph (e)(4) would require that carbon dioxide removal components be contained to prevent contact with the chemicals and the release of airborne particles. Commonly used CO 2 removal systems include lithium hydroxide or soda lime curtains or soda lime cartridges. These systems will require proper handling and may involve using personal protective equipment. The NIOSH report stated that the scrubbing material must not become airborne or otherwise cause respiratory distress or other acute reaction
th the chemicals and the release of airborne particles. Commonly used CO 2 removal systems include lithium hydroxide or soda lime curtains or soda lime cartridges. These systems will require proper handling and may involve using personal protective equipment. The NIOSH report stated that the scrubbing material must not become airborne or otherwise cause respiratory distress or other acute reaction.
Paragraph (e)(5) would require that carbon dioxide removal components be provided and packaged with all necessary means to expedite use. Depending on the type of CO 2 removal component, items such as hangers, racks, and clips may be required to activate and use this component.
Paragraph (e)(6) would require that carbon dioxide removal components be stored in containers that are conspicuously marked with instructions for disposal of used chemicals. Manufacturers would need to provide instructions for disposal of used chemicals.
Paragraph (f) would require the carbon dioxide removal component be tested and evaluated to demonstrate that it can maintain average carbon dioxide concentration at 1.0 percent or less, with excursions not to exceed 2.5 percent under the following conditions: (1) at 55 °F (±4 °F), 1 atmosphere (±0.5 percent), and 50 percent (±0.5 percent) relative humidity; (2) at 55 °F (±4 °F), 1 atmosphere (±0.5 percent), and 100 percent (±0.5 percent) relative humidity; (3) at 90° F (±4 °F), 1 atmosphere (±0.5 percent), and 50 percent (±0.5 percent) relative humidity; (4) at 82 °F (±4 °F), 1 atmosphere (±0.5 percent), and 100 percent (±0.5 percent) relative humidity.
The Agency is proposing testing and evaluating of the CO 2 removal component to assure that the concentration not exceed a 1.0 percent time-weighted average over the rated duration of the refuge alternative with excursions not to exceed 2.5 percent. The provisions in proposed paragraph (f) are consistent with NIOSH's recommendation
±0.5 percent), and 100 percent (±0.5 percent) relative humidity.
The Agency is proposing testing and evaluating of the CO 2 removal component to assure that the concentration not exceed a 1.0 percent time-weighted average over the rated duration of the refuge alternative with excursions not to exceed 2.5 percent. The provisions in proposed paragraph (f) are consistent with NIOSH's recommendation.
MSHA recognizes that some CO 2 scrubbing components may not perform as well as others and that the most commonly used CO 2 scrubbing chemicals performed their function within an acceptable range of the conditions found in underground mines. The testing procedure that would be required under proposed paragraphs (f)(1) through (4) are representative of extreme conditions that CO 2 scrubbing components may be exposed to in different underground mines. The increased temperature and humidity ranges between these provisions reflect increases that would result from occupancy of a refuge alternative, although MSHA assumes that some body heat and moisture generation will be dissipated by contact with the refuge alternative or mine roof, ribs, and floor.
Therefore, it is important to evaluate these CO 2 scrubbing components and determine the differences in levels of effectiveness with currently available components. This will enable mine operators to make more informed choices in selecting scrubbing components to be used in their particular mining operation.
Paragraph (g) would require that respirators or breathing apparatus used with a breathable air component (1) be NIOSH-approved with a means of flow and pressure regulation; (2) be equipped with fittings that connect only to a breathable air compressed line; (3) allow for communication, and the provision of food, and water while preventing the entry of any outside atmosphere; and (4) be capable of being worn for up to 96 hours. The proposed rule addresses the need to have provisions to assure the safe use of respirators or breathing apparatus
and pressure regulation; (2) be equipped with fittings that connect only to a breathable air compressed line; (3) allow for communication, and the provision of food, and water while preventing the entry of any outside atmosphere; and (4) be capable of being worn for up to 96 hours. The proposed rule addresses the need to have provisions to assure the safe use of respirators or breathing apparatus.
Paragraph (g)(1) would require that respirators or breathing apparatus used for a breathable air component have a NIOSH approval with a means of flow and pressure regulation.
Paragraph (g)(2) would require that respirators or breathing apparatus be equipped with fittings that connect only to a breathable air compressed line. This provision would prevent respirators from being connected to piping that is not designed for breathing apparatus or to gas sources that are not capable of sustaining life. Compressed air regulating valves and supply hoses are generally shipped with quick-connect industrial interchange safety fittings/couplings that prevent accidental separation of the hoses. The proposed rule would require that these fittings be
[t]he employer shall ensure that breathing air couplings are incompatible with outlets for nonrespirable worksite air or other gas systems. No asphyxiating substance shall be introduced into breathing air lines. Paragraph (g)(3) would require that respirators or breathing apparatus used with breathable air components allow for communication, and the provision of food and water while at the same time preventing the entry of any outside atmosphere. MSHA is proposing this requirement because communications with and between persons in refuge alternatives to convey and share information are vital to mine rescue efforts. The knowledge of where persons are in refuge alternatives, their condition and the conditions in the mine may make the difference between life and death in a post-accident crisis
e preventing the entry of any outside atmosphere. MSHA is proposing this requirement because communications with and between persons in refuge alternatives to convey and share information are vital to mine rescue efforts. The knowledge of where persons are in refuge alternatives, their condition and the conditions in the mine may make the difference between life and death in a post-accident crisis. In addition, being able to consume food and water is critical for the 96-hour confinement. MSHA believes that the proposed requirements could be met with full-faced respirators or breathing apparatus that have ports for the use of liquids, such as those used by commercial divers.
Paragraph (g)(4) would require that respirators or breathing apparatus used with breathable air components be capable of being worn for up to 96 hours. The refuge alternative standard would require that breathable air be provided in the refuge alternative at all times. Among the concerns addressed by this provision are that if respirators or apparatus are required to be worn for extended periods of time, the respirators or breathing apparatus would need to be of such a type or configuration that it would not become dislodged when sleeping or when activities are performed.
Paragraph (h) would require that an applicant prepare and submit a risk analysis to assure that the breathable air component will not cause an ignition. The proposed provision requires that an analysis be conducted to evaluate the potential fire and ignition risks of the equipment and components.
Paragraph (h)(1) would require that the risk analysis specifically address oxygen fire hazards and fire hazards from chemicals used for removal of carbon dioxide. This provision addresses MSHA's specific concern that the use of oxygen presents inherent potential fire hazards. The provision also focuses on assuring that fire hazards from chemicals used for removal of carbon dioxide are addressed by manufacturers of refuge alternative components
alysis specifically address oxygen fire hazards and fire hazards from chemicals used for removal of carbon dioxide. This provision addresses MSHA's specific concern that the use of oxygen presents inherent potential fire hazards. The provision also focuses on assuring that fire hazards from chemicals used for removal of carbon dioxide are addressed by manufacturers of refuge alternative components.
Paragraph (h)(2) would require that the risk analysis identify the means used to prevent any ignition source. This provision addresses the need to assure that refuge alternative manufacturers analyze inherent potential fire hazards and, if any potential exists, that the mitigation plan includes the means to prevent ignition of breathable air component equipment or materials.
Paragraph (i) would require that the breathable air component shall include a fire extinguisher that (1) is compatible with the chemicals used for removal of carbon dioxide; and (2) uses a non-toxic extinguishing agent that does not produce a hazardous by-product when heated or activated. This paragraph addresses the need to assure that refuge alternative manufacturers analyze inherent potential fire hazards and develop means to prevent the ignition of breathable air component equipment or materials. The proposed requirements in paragraphs (h)(1) and (2) would help assure that the fire extinguisher used in a refuge alternative or component does not contribute to a secondary fire or explosion. The provisions would assist MSHA in determining that materials used in the fire extinguisher are safe for use in an underground mine and do not give off harmful gases when exposed to heat.
Section 7.507 Air-Monitoring Components
Proposed § 7.507(a) would include requirements for an air-monitoring component that provides persons inside the refuge alternative with the ability to determine the concentrations of carbon dioxide, carbon monoxide, oxygen, and methane, inside and outside the structure, including the airlock
nd mine and do not give off harmful gases when exposed to heat.
Section 7.507 Air-Monitoring Components
Proposed § 7.507(a) would include requirements for an air-monitoring component that provides persons inside the refuge alternative with the ability to determine the concentrations of carbon dioxide, carbon monoxide, oxygen, and methane, inside and outside the structure, including the airlock. This proposal would assure that breathable air is properly monitored and that air-monitoring equipment is properly inspected, tested, maintained, and stored so that it is fully charged and available for immediate use.
The monitoring of these gases is critical to the survival of miners occupying a refuge alternative. The proposal includes the recommended values provided in the NIOSH report for oxygen, carbon monoxide, and carbon dioxide. NIOSH recommended values and gas concentration ranges that would assure that the quality of breathable air is maintained. The ability to monitor the atmosphere outside the refuge alternative would assist miners inside the refuge alternative in making crucial decisions in the event of a mine emergency. Additionally, methane would be monitored to negate the possibility of oxygen deficiency or the potential for explosion.
Paragraph (b) would require that refuge alternatives designed for use in mines with a history of harmful gases, other than carbon monoxide, carbon dioxide, and methane be equipped to measure those harmful gas concentrations. Some mines have a history of liberating harmful gases such as hydrogen sulfide, volatile hydrocarbons, or sulfur dioxide. Miners would need to be prepared for potential liberating of these harmful gases and have appropriate monitoring equipment readily available.
Paragraph (c) would require that the air-monitoring component be inspected or tested and the test results are included in the application
e mines have a history of liberating harmful gases such as hydrogen sulfide, volatile hydrocarbons, or sulfur dioxide. Miners would need to be prepared for potential liberating of these harmful gases and have appropriate monitoring equipment readily available.
Paragraph (c) would require that the air-monitoring component be inspected or tested and the test results are included in the application. This provision will assure that all types of monitors or detectors that are included in the refuge alternative will be tested for the conditions for which they are intended. Performance testing will assure the components will operate for which the air monitoring is intended as well as meet the intrinsic safety requirements. Additionally, visual inspection, calibration, and performance test reports will need to be included in the application to verify performance.
Paragraph (d) would require that all air-monitoring components be approved as permissible by MSHA and the MSHA approval number be specified in the application. MSHA will only accept MSHA approved permissible components to assure an explosion hazard does not exist in an explosive atmosphere and the components will serve the purpose for which they are intended. MSHA would allow third party testing of the components for air monitoring. Approval information will assure the components are performance-tested for safe usage in the refuge alternative.
Paragraph (e) would require that air-monitoring components meet the following: (1) The total measurement error, including the cross-sensitivity to other gases, shall not exceed ±10 percent of the reading, except as specified in the approval, and (2) the measurement error limits not exceed after startup, after 8 hours of continuous operation, after 96 hours of storage, and after exposure to atmospheres with a carbon monoxide concentration of 999 ppm (full scale), a carbon dioxide concentration of 3 percent, and full-scale concentrations of other gases
n the instruments' specified acceptable limits, or when the instrument is in need of calibration, can result in the measurement value falling outside the ±10% limit. Measurements that fall outside of the ±10% limit are not in compliance. The applicant needs to determine what environmental or calibration issues exist and resolve them to keep the combined instrument and measurement error within ±10%.
Paragraph (e)(2) would require testing to demonstrate that the gas monitors or detectors will afford miners the capability to determine accurate gas concentrations throughout the duration of refuge occupancy and at different parameters such as startup, after 8 hours of continuous operation, during storage when continuously exposed to the maximum recommended gas concentrations, and at other concentrations much higher than the recommended maximum values. This requirement takes into account the effects high gas concentration levels may have on these measurements over extended periods of time. A consensus standard for instruments, ANSI/ISA-92.02.01, Part I-1998 Performance Requirements for Carbon Monoxide Detection Instruments (50-1000 ppm full scale), specifies carbon monoxide instrument range limits of 1000 ppm, 2000 ppm overload, and the standard specifies these instruments be able to withstand a carbon monoxide shock loading of 4000 ppm.
Paragraph (e)(3) would require that calibration gas values be traceable to the National Institute for Standards and Testing (NIST) “Standard Reference Materials” (SRMs). This procedure will assure proper calibration of the air-monitoring equipment. These standards are recognized and accepted by industry. This provision is based upon existing § 7.86(b)(16), which references NIST SRMs.
Paragraph (e)(4) would require that the analytical accuracy of the calibration gas values be within 2.0 percent of NIST gas standards. This provision is based upon existing § 7.86(b)(16), which also references analytical accuracy of calibration gases within 2 percent of NIST gas standards
d and accepted by industry. This provision is based upon existing § 7.86(b)(16), which references NIST SRMs.
Paragraph (e)(4) would require that the analytical accuracy of the calibration gas values be within 2.0 percent of NIST gas standards. This provision is based upon existing § 7.86(b)(16), which also references analytical accuracy of calibration gases within 2 percent of NIST gas standards.
Paragraph (e)(5) would require that the analytical accuracy of the span gas values be within 2.0 percent of NIST gas standards. This provision is based upon existing § 7.86(b)(17) which also references analytical accuracy of span gases within 2 percent of NIST gas standards.
Paragraph (e)(6) would require the detectors be capable of being kept fully charged and ready for immediate use. MSHA needs to assure that the detectors are reliable and ready to use for maintaining persons as necessary over the 96-hour period.
Section 7.508 Harmful Gas Removal Components
This section addresses removing harmful gases to assure that breathable air is maintained for persons occupying refuge alternatives during the 96-hour period.
Paragraph (a)(1) would require purging or other effective methods be provided for the airlock to dilute the carbon monoxide concentration to 25 ppm or less and the methane concentration to 1.5 percent or less as persons enter, within 20 minutes of miners activating the refuge alternative. The NIOSH recommended value of maximum concentration of carbon monoxide is 25 ppm. This provision is intended to address evacuating contaminated air by forcing the contaminated air out of the refuge alternative environment. Airlocks are intended to speed up the process of ingress and egress, because this is a smaller volume as compared to the interior space to purge. MSHA believes that following the miners' attempt to escape and time required for constructing and activating the refuge alternative, the SCSRs would allow 20 minutes for purging the airlock to establish a breathable air atmosphere
lternative environment. Airlocks are intended to speed up the process of ingress and egress, because this is a smaller volume as compared to the interior space to purge. MSHA believes that following the miners' attempt to escape and time required for constructing and activating the refuge alternative, the SCSRs would allow 20 minutes for purging the airlock to establish a breathable air atmosphere.
In addition, purge air should be provided from compressed air cylinders. The allowable carbon monoxide contamination level is the NIOSH recommended value contained in the NIOSH report. The methane concentration action level in 30 CFR 75.323(b)(2)(i) of less than 1.5 percent is the limit established for persons to be allowed to occupy an area.
Paragraph (a)(2) would require that chemical scrubbing or other effective methods be provided to maintain the average carbon dioxide concentration in the occupied structure at 1.0 percent or less with excursions not to exceed 2.5 percent. The provision addresses the harmful effects of carbon dioxide, a natural asphyxiant produced through human respiration. To prevent the accumulation of harmful concentrations of carbon dioxide, scrubbing systems have been developed to chemically absorb the carbon dioxide. Carbon dioxide scrubbing systems are described as active or passive. Passive systems rely solely on natural air currents for the air to react with the chemical bed. Passive systems chemicals are usually packaged in curtains that are suspended in the refuge chamber environment. Active systems were designed to increase efficiency of CO 2 scrubbing systems. This is accomplished by forcing the air through the chemical bed by fans or compressed air. The recommended average carbon dioxide concentration came from the NIOSH report.
Paragraph (b)(1) would require that chemicals used in harmful gas removal be contained such that when stored or used they cannot come in contact with persons. Because these harmful gas removal chemicals are caustic, they would need to be contained
y forcing the air through the chemical bed by fans or compressed air. The recommended average carbon dioxide concentration came from the NIOSH report.
Paragraph (b)(1) would require that chemicals used in harmful gas removal be contained such that when stored or used they cannot come in contact with persons. Because these harmful gas removal chemicals are caustic, they would need to be contained. One way of packaging these chemicals is in curtains or cartridges that are isolated so that contact with or exposure to the chemicals is prevented. MSHA does not condone the use of uncontained materials because of the caustic nature of these materials. Chemicals must be activated without com

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Source: Frix Law Library, https://www.frixlaw.com/law-library/statutes/FR_PRORULE_E8-13565. Check the current official text before relying on it. Not legal advice.