After reviewing more than 100,000 pages of documents produced by Murray Energy, which operates the mine, and more than 300,000 pages from the Labor Department, Miller said the investigation found that the accident resulted from a mining plan that "never should have been submitted by the mine safety operator and never been approved by the Mine Safety and Health Administration," mainly because the March bounce before the accident should have alerted those involved that the mine was unsafe.

Two attorneys, one representing Murray Energy and responding on behalf of Genwal Resources, and the other representing Adair directly, responded to Miller's press conference.

"As with many of his prior statements, there is no credible basis for Mr. Miller's reckless allegations," said attorney Kevin N. Anderson, who was speaking for Genwal. "They are merely political grandstanding as he continues to play to his constituents. We are confident that any impartial investigator will reject Mr. Miller's allegation."

Anderson acknowledged the possibility of a criminal investigation has been in play for some time. "Mr. Miller sent a letter last month to the Justice Department recommending a criminal investigation of Laine Adair, the general manager at Genwal Resources' Crandall Canyon Mine. This callous inference is based on a radically incomplete review of the facts by Mr. Miller and ignores contradictory records and prior investigators' findings."

The House committee used Northwest Corp., an engineering firm, to re-evaluate the work Agapito Associates did in creating the mining plan at Crandall Canyon and to figure out whether MSHA should have approved an amendment concerning the mine's roof control plan and other technical matters.

During the course of its investigation, which started shortly after the August accident, the committee learned that Murray Energy and its subsidiaries knew about a "significant bump that occurred within the mine on or about March 10, 2007," but did not properly report it to MSHA. Instead, mine management invited the Bureau of Land Management to the mine.

"This is curious: While MSHA is the federal agency responsible for the health and safety of mine workers, BLM is the federal agency responsible for collecting lease payments from mining companies that operate on federal lands. The mine operator called BLM," according to the committee report.

During a deposition for the investigation, Allyn Davis, MSHA District 9 supervisor, told the committee that photos of the damage after the March bump and his conversations with Adair about the bump "don't match." Miller said Adair "minimized the severity of the March bump" based on what the committee learned.

"It is quite possible that had MSHA known the full severity of the March bump, MSHA would not have approved the subsequent development and retreat mining of the south barrier," according to the committee's report.