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CHARLESTON, W.Va. -- More than three-quarters of the samples taken from Massey Energy's Upper Big Branch Mine did not comply with existing standards for controlling the buildup of explosive coal dust underground, federal investigators have revealed.
This potentially key evidence, first revealed to families of the mine disaster victims Thursday night, supports the theory that a buildup of coal dust might have made a methane ignition at Upper Big Branch far worse than it otherwise would have been.
During a Friday morning media briefing, U.S. Mine Safety and Health Administration officials said 79 percent of the more than 1,800 dust samples taken at Upper Big Branch exceeded federal limits for the allowable "combustible content."
MSHA officials were measured in their public remarks about the samples, saying further analysis is still needed and a final conclusion cannot yet be reached about the role of coal dust in the April 5 explosion that killed 29 miners.
"It's going to be fair to say that coal dust played a role," MSHA coal administrator Kevin Stricklin told reporters, "but we don't know how big of a role."
Massey Energy quickly challenged the MSHA data, calling it "unproven or faulty," and noted that the agency lost a major case over dust sampling following the deaths of 13 miners in an Alabama explosion nearly a decade ago.
"MSHA's narrow-minded focus on compromised coal-dust evidence is doing a disservice to those UBB families entitled to concrete answers unequivocally supported by accurate scientific findings and the facts," the company responded.
The coal-dust sampling data was, by far, the biggest news to emerge from MSHA's Thursday evening meeting with Upper Big Branch families and a Friday morning media briefing, both held as the investigation into the worst U.S. coal-mining disaster in 40 years continued into its sixth month.
Among other news from the MSHA briefing and the earlier meeting with miners' families:
| Investigators have interviewed at least 235 witnesses and have another 20 witnesses on their list for future closed-door sessions. MSHA has not decided if it will seek to question Massey CEO Don Blankenship.
| Massey managers have sent a letter to the West Virginia Office of Miners Health, Safety and Training that challenges subpoenas issued to company officials by the state. Among other things, Massey has objected to MSHA officials taking part in interviews conducted under the authority of state agency subpoenas. Under federal law, MSHA would be able to subpoena witnesses itself only if federal officials decided to hold such sessions in a public hearing.
| Methane detectors indicate the time of the explosion was somewhere between 2:59 p.m. and 3:06 p.m., but MSHA believes other monitors indicate the exact time was 3:02 and 40 seconds. MSHA officials told family members that clocks on the mine's carbon monoxide alarms -- which indicated a potential time for the explosion was 3:08 p.m. -- were off by a few minutes.