Shane Harvey, Massey's general counsel, said the company believes it is "a distinct possibility" that the disaster was a natural event beyond Massey's control.
Other mine safety experts noted that Massey's methane data shows only that the rate the explosive gas was exiting the Upper Big Branch Mine increased greatly in the hours after the disaster, which doesn't necessarily mean anything about how great the methane liberation rate was just prior to the explosion.
At a news conference on April 26, Massey board member Stan Suboleski told reporters that the last methane checks -- taken just before the shift change that was occurring when the mine exploded -- showed no methane problems.
"No hazards were found and methane measurements ranged from zero to nearly zero, a max of three-tenths of 1 percent," Suboleski said.
MSHA said Thursday that elevated methane liberation after the explosion "would be expected if the explosion damaged ventilation controls and if mine gases from sealed areas or from the longwall gob were pulled into the ventilation air current.
"This would cause a rise in methane after the explosion and could account for elevated methane in the samples," the MSHA statement said.
The Gazette has previously disclosed MSHA records that documented methane "outbursts" from the Upper Big Branch Mine's floor in 2003 and 2004, but neither MSHA nor Massey had provided complete answers about what steps -- if any -- were taken to avoid repeats of those incidents or at least mitigate the potential damage.
McAteer has said that his independent team is looking into what Massey did following those incidents and whether state and federal agencies required proper safeguards by the company.
"If a mining method or a mine seam is vulnerable or prone to methane outbursts, then the question is what precautions were taken or have been taken or have been implemented to prevent these outbursts from turning into a cataclysmic event," McAteer said in an interview.
In his memo, written for top Labor Department lawyer Patricia Smith, MSHA's Wagner outlined the long list of ventilation and related violations by Massey subsidiary Performance Coal at Upper Big Branch.
Contrary to Massey's assertion that its in-house engineers knew better than MSHA how to ventilate the mine, Wagner wrote that company officials did not even have a copy of federal safety regulations they were supposed to follow. MSHA sent the company a copy in early December as "a courtesy," Wagner wrote.
But Wagner's memo did not include any formal MSHA documents to back up its version of events, and the Obama administration has posted incomplete copies of the Upper Big Branch's ventilation files on the MSHA Web site.
Phil Smith, a spokesman for the United Mine Workers, said the back-and-forth between Massey and MSHA demonstrates that the union and others were right to try to persuade MSHA to conduct its disaster investigation through an open, public hearing.
"One of the reasons the UMWA called for an open investigation at the outset was to make it much harder for Massey to use public relations and media manipulation to misdirect attention from the company's potential culpability in this disaster," Smith said. "That is, in fact, exactly what has happened, and what could have been a strong investigation now has the potential to be trivialized by the army of straw men coming out of Massey's high-priced Washington PR firm."
Reach Ken Ward Jr. at kw...@wvgazette.com or 304-348-1702.