A sealing material that failed in two deadly explosions can no longer be used in coal mines until tests determine whether it is safe, a federal official said Monday.
The U.S. Mine Safety and Health Administration is banning the construction of any new mine seal that uses Omega Blocks or any other material except for solid concrete blocks, said David Dye, the agency's acting administrator.
Burrell Mining Inc., of New Kensington, Westmoreland County, manufactures Omega Blocks. Charles Booth Jr., owner and CEO of parent company Burrell Group Inc., couldn't be reached for comment.
A Jan. 2 explosion in the Sago Mine in Buckhannon, W.Va., started in a sealed-off area, demolished several Omega Block seals and directly killed a miner working near those seals. The failure of the seals also killed 11 other miners who died of carbon monoxide poisoning from gases created by the explosion.
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An explosion Saturday in the Darby No. 1 Mine near Holmes Mill, Ky., killed two miners directly. Another three died from carbon monoxide poisoning, according to The Associated Press.
Federal investigators haven't determined whether the Darby explosion started in a sealed area, but rescue teams reported several Omega Block seals were demolished by the explosion.
"While MSHA investigates this tragedy to determine the cause and location of the explosion, we are concerned that the alternative seals did not withstand a blast and exposed miners to unacceptable hazards," Dye said.
In a related development, federal officials confirmed the three Kentucky miners who died from carbon monoxide poisoning were using the same air packs as the 11 poisoned West Virginia miners. The air packs are manufactured by CSE Corp. of Monroeville. (See story on page A6.)
The agency has allowed mine operators to use "alternative seals" such as the dense foam Omega Blocks since 1992. The approval was based on tests showing several alternative designs withstood the same design pressure -- 20 pounds per square inch -- as the concrete block seals.
The federal order doesn't require mine operators to remove alternative seals, but it does require them to start monitoring the atmosphere behind them to see if it is explosive. If so, mine operators will have to take additional precautions to protect the miners from an explosion, Dye said. Mine operators also will have to test the structural integrity of any existing alternative seals, he said.
MSHA is still working out the methods by which mine operators will carry out these mandates, said agency spokesman Dirk Fillpot.
The ban on constructing new alternative seals will remain in effect until testing verifies their ability to withstand explosive forces, Dye said. As part of the Sago investigation, the National Institute of Occupational Safety and Health already has run a new test on an Omega Block seal that confirmed it meets the agency's specifications.
Officials at International Coal Group, which owns the Sago Mine, contend the agency's 20-pounds-per-square-inch standard is inadequate. The Ashland, Ky., company hired a structural engineer, who determined explosive forces in the West Virginia mine reached as high as 60 to 90 psi.