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MSHA News Release: [05/18/2007]
Contact: Dirk Fillpot          Amy Louviere
Phone:    (202) 693-9406   (202) 693-9423
Release Number 07-751-NAT

U.S. Labor Department's MSHA issues emergency temporary standard
MSHA takes immediate action to strengthen mine safety

ARLINGTON, Va. - For only the fourth time in the history of the Mine Act, the U.S. Department of Labor's Mine Safety and Health Administration (MSHA) today issued an emergency temporary standard (ETS). It will become effective immediately upon publication in the Federal Register on May 22, exceeding by seven months the deadline established under the Mine Improvement and New Emergency Response (MINER) Act of 2006. This latest ETS is in response to the danger that miners face in the event of an underground seal failure.

"Based on MSHA's accident investigation reports of the Sago and Darby mine explosions, MSHA's in-mine seal evaluations and review of technical literature, and the National Institute for Occupational Safety and Health's reports on explosion testing and modeling, we have concluded that immediate action is necessary to provide additional protections for our nation's underground coal miners," said Richard E. Stickler, assistant secretary of labor for mine safety and health.

The ETS includes requirements to strengthen the design, construction, maintenance and repair of seals, as well as requirements for sampling and controlling atmospheres behind seals. For the construction of new seals, it establishes a three-tiered approach to preventing or withstanding overpressure-loading: (1) Seals may be constructed at 50psi, but the atmosphere behind them must be monitored and maintained inert. (2) If the atmosphere is not monitored and maintained inert, the seals must be constructed at 120psi. (3) Where higher explosion pressures are possible within sealed areas that are not monitored or maintained inert, the seals must be greater than 120psi.

Mine operators must submit design and installation applications for MSHA approval. The seal design plan must be certified by a professional engineer, and proper construction must be certified by the operator. In order to assist operators in complying with this regulation, MSHA has posted preliminary designs for 50psi and 120psi seals on the agency's Web site at For new 50psi seals and existing seals, operators must follow a gas sampling protocol that includes baseline sampling and periodic monitoring. They must develop an action plan to address explosive atmospheres in sealed areas, including withdrawal of miners if oxygen and methane reach certain levels. In addition, the ETS requires that insulated cables be removed from future areas to be sealed, and it prohibits welding, cutting and soldering with an arc or flame within 150 feet of a seal.

Seals are used to isolate and contain mined-out areas where coal dust and gas might accumulate. They must be designed to withstand elevated pressures and contain explosions by preventing potentially explosive or toxic gasses from entering the active working areas of underground coal mines.

MSHA will hold four public hearings on the ETS: July 10 in Morgantown, W.Va., July 12 in Lexington, Ky., July 17 in Denver, Colo., and July 19 in Birmingham, Ala.

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