CHARLESTON, W.Va. — Air samples did not show high levels of explosive gases just before an explosion in a West Virginia coal mine that killed 29 workers, and what caused the disaster remains unknown, the mine's owner said Monday.
Massey Energy Co. board director Stanley Suboleski said the samples were taken by foremen as part of a shift-change exam at the Upper Big Branch mine, just "tens of minutes" before the blast. Massey spokesman Jeff Gillenwater later said he could not be more specific about the time.
The examination also showed that air flow in the underground mine was fine, Suboleski said.
"All the indicators are that at the start of the shift, everything was okay," said Suboleski, a mining engineer.
Suboleski, two other Massey board directors and chief executive Don Blankenship spoke at a news conference Monday to address several issues related to the explosion, the nation's worst coal mining disaster in 40 years.
"This has left us humbled and hurt, and searching for answers," Blankenship said.
Federal regulators have identified highly explosive methane gas, coal dust or a mixture of the two as the likely cause of the blast, but the ignition source is unknown. Methane levels in the mine remain unsafe, and it could be a month before investigators can get inside to determine what caused the blast.
The nation's top mine safety official is expected to testify at a Senate hearing today, and President Barack Obama has ordered a broad review of coal mines with poor safety records.
While saying that he was not alleging they had made the mine less safe, Suboleski cited how U.S. Mine Safety and Health Administration officials had ordered changes to the ventilation system that Massey's engineers initially opposed. These changes made the system more complicated and reduced its air flow, he said.
MSHA spokeswoman Amy Louviere said, "The system in place could not be effectively maintained by the operator to ventilate the mine. Massey had one of two choices: either repair the conditions or revise the ventilation plan."
The company also promised to provide financial packages to the families of the miners killed. It will include five times the miner's annual pay as life insurance benefits, an additional payment to surviving spouses, health coverage for them and dependent children, and four years' worth of college or vocational education at any accredited school in West Virginia for those children.