Since early June, federal and state investigators have focused on, among other things, incidents in 2003 and 2004 when methane "outbursts" from the mine floor inundated the Upper Big Branch with the explosive gas. No ignitions or injuries were reported in those two incidents.

MSHA documents show Massey had proposed a number of steps, including de-gasification wells, to prevent a recurrence, and federal experts proposed additional measures. But MSHA has been unable to explain which of those steps were eventually implemented, and Massey has not responded to questions about the matter.

During MSHA's meeting with families Tuesday night, Stricklin was adamant that a methane outburst like the ones in 2003 and 2004 did not cause the April 5 explosion, according to several people who attended the meeting. But during the media call and interview Wednesday, Stricklin said the issue needed more review before any conclusions could be made.

"I don't think we're ready to say it hasn't happened," Stricklin said. "It's one of the things we need to look at."

Stricklin said that even an event like that described in Massey's theory of the Upper Big Branch disaster -- a huge inundation of methane from a floor crack -- is preventable if mine operators take appropriate steps.

Mine operators can de-gas the area prior or during mining, and can be sure to eliminate any potential ignition sources in the vicinity. And if operators apply appropriate amounts of crushed limestone, or rock dust, any ignition that does occur could be kept small enough to avoid serious injuries or deaths.

Some experts say another option could have been to switch from longwall mining to the use of only continuous mining machines, a move that could have limited floor heaving but made the mine far less efficient and profitable.

"Methane has to be dealt with at the mines every day," Stricklin said. "It shouldn't ever get to a situation where we say we had a massive inundation and couldn't do anything about it."

Wednesday's MSHA briefing prompted more news releases in Massey Energy's continuing public relations battle with the agency.

First, Massey issued a statement announcing its release of photos showing the crack in the longwall section of the mine. Most of the photos had already been shown to reporters during an online news conference three weeks ago, but not permanently posted on Massey's special Upper Big Branch blog.

Then, Massey issued a follow-up statement to make public a page from the MSHA investigation's photo log to prove that a government photographer took the photos on July 14 at Upper Big Branch.

MSHA officials had not disputed the existence of floor cracks, only Massey's description of their size and the company's suggestion that the presence of cracks might mean there was nothing Massey could have done to prevent the disaster.

While family members say Massey told them the largest of the mine cracks measured 100 to 150 feet long, the company's public relations firm said Wednesday the crack had not been measured, but Massey believes "that it is approximately 50 feet in length."

MSHA officials told family members Tuesday night that the largest of the cracks measured about 10 feet long, according to several people who attended the meeting.

Main said that MSHA officials have no plans to provide more regular briefings to the press or the public, or take any other steps to combat Massey's aggressive public relations campaign to point fingers at the agency or characterize what may have caused the disaster.

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

CHARLESTON, W.Va. -- Federal investigators on Wednesday disputed Massey Energy's description of the size of a crack in the Upper Big Branch Mine's floor, but said they continue to closely examine possible connections between floor fracturing and the April 5 explosion that killed 29 miners.

U.S. Mine Safety and Health Administration officials also disclosed that they have not been able to locate records that describe what preventative steps -- if any -- Massey or MSHA eventually took after a pair of "methane outbursts" from the Upper Big Branch floor in 2003 and 2004.

Kevin Stricklin, MSHA's coal administrator, said agency officials have searched their files and put in a request for potentially relevant documents from government archives, but so far haven't turned up anything.

"We just don't have any information on that yet," Stricklin said in an interview with The Charleston Gazette.

Stricklin discussed the issue in more detail following a telephone news conference in which he and MSHA chief Joe Main updated the media on the ongoing investigation. The news event was scheduled to follow a closed-door meeting Tuesday evening with the disaster victims' families.

Main said investigators had interviewed 166 witnesses, collected 250 pieces of evidence and taken more than 1,800 samples from the Raleigh County mine. Main estimated the probe is about halfway done and emphasized that large portions of the mine, including two active mining sections, have not been examined by the investigation team, making it far too early to draw any serious conclusions about the disaster's cause.

Investigators have begun issuing subpoenas for all future witnesses and are starting to move up to higher level mine managers and Massey corporate officials.

"We are going to scour the Earth to determine what happened at the Upper Big Branch Mine," Main said.

Main said investigators have found eight hand-held methane detectors, along with two methane monitors from the mine's longwall mining section, but said it is far too soon to know if any of the safety equipment was tampered with or malfunctioned.

MSHA officials also confirmed that two executives from Massey's Performance Coal Co. subsidiary were discovered inside the Upper Big Branch Mine after the explosion, but before MSHA took control of access to the operation.

It's not clear what the two men were doing, though Stricklin said mine employees often rush underground after an accident to try to find survivors. Stricklin did not name the two men, but said they did not have mine rescue training and "had no reason to be underground."

Main and Stricklin responded to Massey's theory that the disaster may have been caused by a flood of methane gas from a massive floor crack, an occurrence Massey has suggested it could do nothing to prevent.

During their telephone news conference, Main and Stricklin said family members reported that Massey had told them during a private meeting last week that investigators had found a 100- to 150-foot long crack in mine floor.

But Main said, "I have seen nothing to represent a crack that large, nor have I talked to anybody who has."

Stricklin said investigators have seen floor "heaving," smaller cracks mixed with heaped up rock and earth. Heaving is typically caused by the shifting of ground pressures during highly mechanized longwall mining, and can release methane from coal seams and geologic formations below.

Since early June, federal and state investigators have focused on, among other things, incidents in 2003 and 2004 when methane "outbursts" from the mine floor inundated the Upper Big Branch with the explosive gas. No ignitions or injuries were reported in those two incidents.

MSHA documents show Massey had proposed a number of steps, including de-gasification wells, to prevent a recurrence, and federal experts proposed additional measures. But MSHA has been unable to explain which of those steps were eventually implemented, and Massey has not responded to questions about the matter.

During MSHA's meeting with families Tuesday night, Stricklin was adamant that a methane outburst like the ones in 2003 and 2004 did not cause the April 5 explosion, according to several people who attended the meeting. But during the media call and interview Wednesday, Stricklin said the issue needed more review before any conclusions could be made.

"I don't think we're ready to say it hasn't happened," Stricklin said. "It's one of the things we need to look at."

Stricklin said that even an event like that described in Massey's theory of the Upper Big Branch disaster -- a huge inundation of methane from a floor crack -- is preventable if mine operators take appropriate steps.

Mine operators can de-gas the area prior or during mining, and can be sure to eliminate any potential ignition sources in the vicinity. And if operators apply appropriate amounts of crushed limestone, or rock dust, any ignition that does occur could be kept small enough to avoid serious injuries or deaths.

Some experts say another option could have been to switch from longwall mining to the use of only continuous mining machines, a move that could have limited floor heaving but made the mine far less efficient and profitable.

"Methane has to be dealt with at the mines every day," Stricklin said. "It shouldn't ever get to a situation where we say we had a massive inundation and couldn't do anything about it."

Wednesday's MSHA briefing prompted more news releases in Massey Energy's continuing public relations battle with the agency.

First, Massey issued a statement announcing its release of photos showing the crack in the longwall section of the mine. Most of the photos had already been shown to reporters during an online news conference three weeks ago, but not permanently posted on Massey's special Upper Big Branch blog.

Then, Massey issued a follow-up statement to make public a page from the MSHA investigation's photo log to prove that a government photographer took the photos on July 14 at Upper Big Branch.

MSHA officials had not disputed the existence of floor cracks, only Massey's description of their size and the company's suggestion that the presence of cracks might mean there was nothing Massey could have done to prevent the disaster.

While family members say Massey told them the largest of the mine cracks measured 100 to 150 feet long, the company's public relations firm said Wednesday the crack had not been measured, but Massey believes "that it is approximately 50 feet in length."

MSHA officials told family members Tuesday night that the largest of the cracks measured about 10 feet long, according to several people who attended the meeting.

Main said that MSHA officials have no plans to provide more regular briefings to the press or the public, or take any other steps to combat Massey's aggressive public relations campaign to point fingers at the agency or characterize what may have caused the disaster.

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