| U.S. Department of
Labor |
Mine Safety and Health Administration 1100 Wilson Boulevard Arlington, Virginia 22209-3939 |
 |
| EFFECTIVE DATE: 12/18/09 | EXPIRATION DATE: 03/31/2011 |
PROGRAM POLICY LETTER NO. P09-V-14
FROM: KEVIN G. STRICKLIN
Administrator for
Coal Mine Safety and Health
LINDA F. ZEILER
Acting Director of Technical Support
SUBJECT: 15 psi Stoppings as Structural Components for Refuge
Alternatives
Scope
This Program Policy Letter (PPL) is intended for Mine Safety and Health Administration (MSHA) Coal Mine Safety and Health (CMS&H) personnel, MSHA Technical Support personnel, coal mine operators, miners' representatives, and other interested parties.
Purpose
This PPL provides mine operators guidance in implementing section 75.1507(b)(2) of MSHA's final rule on Refuge Alternatives for Underground Coal Mines. Section 75.1507(b)(2), which applies to refuge alternatives consisting of 15 pounds per square inch (psi) stoppings constructed prior to an event in a secure space and isolated atmosphere, requires that the Emergency Response Plan (ERP) specify that the refuge alternative can withstand a pressure wave of 15 psi overpressure for 0.2 seconds. This guidance is provided to assist mine operators in constructing a refuge alternative using solid concrete blocks that reliably will withstand a pressure wave of 15 psi overpressure for 0.2 seconds, such that the stoppings will provide effective protection during an emergency.
Policy
This guidance represents MSHA's current thinking with respect to refuge alternatives consisting of 15 psi stoppings. It does not create or confer any rights for any person nor does it operate to bind mine operators or any other members of the public. Mine operators can use an alternative to the approach described in this guidance if the alternative approach satisfies the requirements of Section 75.1507(b)(2). If you are a mine operator, miners' representative, or miner and want to discuss this approach or an alternative approach, you may contact the District Manager for the area in which the mine is located or the individuals identified in this PPL. References to the District Manager in this PPL refer to the Agency's existing consultative process for reviewing ERPs, as opposed to the process for enforcement decisions related to citations.
One of the following methods should be used to ensure that stoppings used as the structural component of a refuge alternative reliably will withstand a pressure wave of 15 psi overpressure for 0.2 seconds:
- 1. Full-scale explosion testing or equivalent means of physical testing; and/or
2. Analytical design and certification
Analytical design and certification should show that the stopping is designed using current, recognized engineering and analytical techniques, which demonstrate the proposed design's capability to reliably resist the 15 psi explosive overpressure for 0.2 seconds. MSHA Technical Support will assist the District Managers with their review of analytical designs.
If a door is to be used in the stopping, the full-scale explosion testing or equivalent means of physical testing; and/or the analytical design and certification should include the stopping and door as a system. Doors should not be evaluated or approved separately. The installation of the door in the stopping is critical in determining its ultimate strength.
In addition to adopting a design derived from the above methods, mine operators may adopt the pre-engineered concrete block design that is based on a modified solid concrete block seal that was designed by the U.S. Bureau of Mines. MSHA's Technical Support group has modified this seal design to function as a 15 psi stopping. The design is attached to this PPL and is also available from MSHA by contacting the individuals identified in this PPL.
Background
MSHA's final rule on Refuge Alternatives for Underground Coal Mines was published on December 31, 2008. Section 75.1506(a)(2) allows mine operators to use refuge alternatives consisting of 15 psi stoppings constructed prior to an event in a secure space and isolated atmosphere. When using this type of refuge alternative, the mine operator must specify in the ERP that the refuge alternative can withstand a pressure wave of 15 psi overpressure for 0.2 seconds.
Authority
Section 316 of the Federal Mine Safety and Health Act of 1977, as amended, 30 U.S.C. § 876; 30 C.F.R. §§ 75.1506(a)(2) and 75.1507(b). MSHA considers this PPL to constitute a statement of agency policy and thus exempt from the requirements of notice-and-comment rulemaking. See 5 U.S.C. § 533(b)(A).
Internet Availability
This PPL may be viewed on MSHA's Home Page at http://www.msha.gov, choosing "Compliance Info," then choosing "Program Policy Letter."
Issuing Offices and Contact Persons
Coal Mine Safety and Health, Division of Safety
Erik Sherer, (202) 693-9523
E-mail: sherer.hubert@dol.gov
Technical Support, Pittsburgh Safety and Health Technology Center
Clete Stephan, (412) 386-6937
E-mail: stephan.clete@dol.gov
Distribution
MSHA Program Policy Manual Holders
Coal Mine Operators
Manufacturers of Communications and Electronic Tracking Systems
Miners' Representatives
Special Interest Groups
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