Its effective date is May 22, and the agency said its deadline will exceed the initial target outlined in the MINER Act of 2006 by seven months.

“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 [NIOSH] reports on explosion testing and modelling, we have concluded that immediate action is necessary to provide additional protections for our nation’s underground coal miners,” MSHA assistant secretary Richard Stickler said Tuesday.

Included in the new ETS is the improvement of the design, construction, maintenance and repair of seals and new requisites for the sampling of air behind seals and keeping it at controlled levels.

According to the 23-page document: “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.”

To aid operators, who must submit their plans for design and installation to the agency for its approval, with their fulfilment of the new rules, MSHA this week posted “preliminary designs” for seals registering 50psi and 120psi on its website. For the former, mines must follow baseline sampling and monitoring details included in the ETS.

“They must develop an action plan to address explosive atmospheres in sealed areas, including withdrawal of miners if oxygen and methane reach certain levels,” the agency said.

“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.”

To collect information on the ETS from the industry public, the agency will hold four meetings throughout the US where attendees are invited to speak and share opinions.

The first will be held July 10 in Morgantown, West Virginia at the Lakeview Golf Resort, while the others will be hosted by the Crowne Plaza Hotel in Lexington, Kentucky (July 12), the Embassy Suites Denver in Colorado (July 17) and the Sheraton Birmingham Hotel in Alabama (July 19).

The comment period will close on July 6, MSHA said. For the complete ETS or for information on the public hearings and process for submitting input, visit http://www.msha.gov/Seals/SealsSingleSource2007.asp.