Mine safety experts have said the explosion was almost certainly caused by a buildup of methane that was somehow ignited, and then made far worse by accumulations of coal dust underground.

Upper Big Branch had been repeatedly cited for violating its mine ventilation plan and for allowing explosive coal dust to accumulate.

During a Jan. 9 inspection that focused on the misdirected air flow, the unnamed MSHA inspector pulled workers on the affected part of the mine aside and asked them about the problem.

"[The workers] informed me that they questioned management about this condition and they were told it was fine, not to worry about it," the MSHA inspector said.

The workers told the inspector they had questioned Performance Coal President Chris Blanchard and company Vice President Jamie Ferguson about the ventilation issue.

Moore, the mine foreman, told the inspector the problem had existed since he took over that job three weeks earlier.

The violation was fixed later that day, but MSHA inspectors cited the company for "unwarrantable failure" to follow safety rules and fined the company $70,000, according to agency records.

"Mr. Moore engaged in aggravated conduct constituting more than ordinary negligence in that he was aware of the condition" for three weeks without making sure it was fixed, the MSHA citation said.

Massey has defended its safety record and company CEO Don Blankenship has said "any suspicion that the mine was improperly operated or illegally operated or anything like that would be unfounded."

In a prepared statement, Massey has also said, "We do not condone any violation of MSHA regulations, and we strive to be in compliance with all regulations at all times."

But during one inspection in early January, mine official Gary May complained that MSHA "comes in here expecting the worst and not giving them the benefit of the doubt," according to the inspector's notes.

"I explained to him that I would be writing what I saw," the inspector added.

Reach Ken Ward Jr. at kw...@wvgazette.com or 304-348-1702.

CHARLESTON, W.Va. -- Three months before last week's deadly explosion, Massey Energy managers at the Upper Big Branch Mine told workers "not to worry" that the flow of air in the mine -- meant to control deadly gases and coal dust -- was headed in the wrong direction, a federal government inspector said in newly released U.S. Mine Safety and Health Administration records.

The comment was made in January, when state and federal inspectors were battling Massey over what MSHA and the state Office of Miners' Health, Safety and Training said were major ventilation problems.

"When questioned, Terry Moore, mine foreman, said he knew of [the] condition and that he asked Everett Hager, superintendent, about it and he was told not to worry about it," the MSHA inspector, whose name was not released, wrote in his official notebook.

The inspector's notes were among the Upper Big Branch enforcement documents MSHA continues to dribble out to the public and the press as federal and state officials begin a long and complex effort to figure out what caused the worst U.S. coal-mining disaster in 40 years.

On Tuesday, Gov. Joe Manchin announced a move that had been expected for several days -- his appointment of longtime mine safety advocate Davitt McAteer to conduct an independent investigation into the deaths of the 29 Upper Big Branch miners.

"We owe it to the families of the 29 miners we lost last week to find out what caused this," Manchin said. "And we owe it to them and every coal miner working today to do everything humanly possible to prevent this from happening again."

McAteer said, "This will be an independent review of the accident and the agencies and we will put together our recommendations on what we can do to improve mine safety overall and prevent another accident like this."

McAteer said that he would hold a public hearing, but was still working out how the format might differ from the one he put together as part of an independent probe of the 2006 Sago Mine disaster.

Among other things, McAteer said he would consider trying to open the process of witness interviews to the press and the public, or at least whether transcripts from those interviews would be released in a timely fashion as the probe progresses.

"I expect we will have periodic briefings with the media to try to provide information," McAteer said.

McAteer said his investigation would be coordinated with the one being conducted by the state mine safety office, but it was not clear yet how it might mesh with MSHA's investigation.

Labor Secretary Hilda Solis and MSHA chief Joe Main have appointed an investigation team, but have not said if they will conduct any of their review in public, whether they will allow families of the victims to be involved, or what sort of examination will be done of MSHA's own potential failures at the Upper Big Branch Mine.

Solis and Main are scheduled to meet Thursday with President Obama, who has ordered them to provide a preliminary report on the potential causes for the disaster.

Various congressional reviews are also expected, but elected officials have not yet said if they will hold hearings in the coalfields to give miners and their families a chance to take part.

Mine safety experts have said the explosion was almost certainly caused by a buildup of methane that was somehow ignited, and then made far worse by accumulations of coal dust underground.

Upper Big Branch had been repeatedly cited for violating its mine ventilation plan and for allowing explosive coal dust to accumulate.

During a Jan. 9 inspection that focused on the misdirected air flow, the unnamed MSHA inspector pulled workers on the affected part of the mine aside and asked them about the problem.

"[The workers] informed me that they questioned management about this condition and they were told it was fine, not to worry about it," the MSHA inspector said.

The workers told the inspector they had questioned Performance Coal President Chris Blanchard and company Vice President Jamie Ferguson about the ventilation issue.

Moore, the mine foreman, told the inspector the problem had existed since he took over that job three weeks earlier.

The violation was fixed later that day, but MSHA inspectors cited the company for "unwarrantable failure" to follow safety rules and fined the company $70,000, according to agency records.

"Mr. Moore engaged in aggravated conduct constituting more than ordinary negligence in that he was aware of the condition" for three weeks without making sure it was fixed, the MSHA citation said.

Massey has defended its safety record and company CEO Don Blankenship has said "any suspicion that the mine was improperly operated or illegally operated or anything like that would be unfounded."

In a prepared statement, Massey has also said, "We do not condone any violation of MSHA regulations, and we strive to be in compliance with all regulations at all times."

But during one inspection in early January, mine official Gary May complained that MSHA "comes in here expecting the worst and not giving them the benefit of the doubt," according to the inspector's notes.

"I explained to him that I would be writing what I saw," the inspector added.

Reach Ken Ward Jr. at kw...@wvgazette.com or 304-348-1702.