Updated

Federal prosecutors should open a criminal investigation into the deaths of nine people in a Utah mine collapse last year, a leading House Democrat said Thursday.

Rep. George Miller, D-Calif., the chairman of the House Education and Labor Committee, said he made a criminal referral to the Justice Department on the August 2007 collapse of the Crandall Canyon mine.

The Mine Safety and Health Administration is still investigating the two cave-ins that killed six miners and three rescuers.

"I was concerned that the mine operator may have willfully misled MSHA about information that could have affected MSHA's decision to approve the mining plans," Miller said.

The U.S. attorney's office in Utah said Thursday it would take Miller's request "very seriously."

A representative of the mining company called Miller's announcement "deplorable."

"There is no credible basis for Mr. Miller's reckless allegations," said Kevin N. Anderson, lawyer for Genwal Resources, Inc., owned by Murray Energy Corp. "They are merely political grandstanding as he continues to play to his constituents."

MSHA spokesman Matthew Faraci said it would be "premature and speculative" to comment on Miller's report.

Rep. Howard "Buck" McKeon of California, the committee's ranking Republican, said there was little new in Miller's report and officials should wait until MSHA finishes its investigation.

UtahAmerican Energy Inc., a subsidiary of Murray Energy, owns the mine.

Miller said UtahAmerican Energy failed to report correctly a March 2007 "bump" — where a pillar or series of pillars holding the mine roof burst — in another section of the mine.

After that accident, plans to work in the area where the miners died should never have been approved by MSHA, Miller said. Miller wants the Justice Department to investigate the mine's general manager, Laine W. Adair, and others.

"I believe that UtahAmerican Energy may have deliberately and significantly downplayed the extent of the March bump in its conversations with MSHA staff," Miller said.

Adair's lawyer, Gregory Poe, said the criminal referral was "deeply disappointing and utterly unjustified."

The Senate Health, Education, Labor and Pensions Committee also asked the Justice Department to investigate the Crandall Canyon collapse in March.