Under MSHA's changes, the incombustible content of dust in all areas of underground mines would have to be at least 80 percent. Higher incombustible percentages would be required where methane is present.
MSHA estimated that the change would cost the nation's 415 underground coal mines a total of $22 million a year for additional rock dust and for employee time applying that rock dust. The agency noted that six coal dust explosions killed 46 miners over the past 26 years, an average of two miners per year.
"MSHA acknowledges that the requirements in this ETS probably would not have prevented all of the deaths from the six explosions, and estimates that the ETS would have prevented approximately one to one and a half deaths per year," MSHA said in a Federal Register notice.
At Thursday's public hearing, several Massey employees and a lobbyist for the West Virginia Coal Association complained that MSHA should be more focused on allowing mine operators to use scrubbers mounted to mining machines to control dust and allowing extended cuts of coal that involve less moving of machines underground.
"That's a major concern we have here in West Virginia," said Chris Hamilton, the coal association's vice president. "That's a much greater concern here throughout West Virginia and Appalachia than putting an additional 5 or 10 or 15 percent more rock dust."
MSHA officials have said Massey's scrubbers weren't meeting dust standards, and that the company is merely upset about the agency blocking extended cuts, which allow more coal to be more quickly mined, but also can create roof-control problems.
On Thursday, MSHA also announced a second phase of its "Rules to Live By" enforcement initiative to target the types of violations agency officials believe can lead to explosions and fires.
"Too many miners have lost their lives in catastrophic accidents over the past 10 years," Main said. "That is simply unacceptable."
Reach Ken Ward Jr. at kw...@wvgazette.com or 304-348-1702.