Senators demanded answers from MSHA chief Richard Stickler yesterday, accusing his agency of ignoring signs of unsafe conditions at the Crandall Canyon mine in Utah, which collapsed last month, entombing six miners, theLos Angeles Timesreports.

At the first congressional hearing on mine safety since the Aug. 6 collapse, members of a Senate Appropriations subcommittee cited multiple safety violations at the mine, a lack of substantial fines for those violations, and roof collapses or "bumps" at the mine beginning in March.

"With these nine deaths," said Sen. Arlen Specter (R-Pa.), referring to the six trapped miners and three rescuers killed ten days later, "there was criminal negligence here with all these threats being known."

But MSHA’s Stickler told the panel that he was unaware of the March bumps until after the August mine disaster. He said he was unable to answer many of the questions posed by the senators until his agency's investigation is completed.

Three mine experts blasted Stickler, according to the Timesreport, for his agency's approval in June of a plan to allow retreat mining — whereby miners extract mineral remaining in pillars of coal and hurry out before the roof collapses — in the area where the six men were trapped.

Cecil E. Roberts, president of the United Mine Workers of America, and J. Davitt McAteer, a former mine safety chief, said Stickler elevated the possibility of a roof collapse by permitting retreat mining in a mine that had a history of bumps. The National Institute for Occupational Safety and Health (NIOSH) defines a mine bump as a sudden outburst of coal and rock caused when stresses in a pillar of coal, left for support of a work area, cause the pillar to rupture.

Rescue efforts at the mine were suspended indefinitely Friday, apparently forever entombing the six trapped miners. It is not known whether the six men survived the first thunderous mountain shudder that caused the mine's support system to collapse.

Three rescue workers died during a second collapse Aug. 16, bringing a halt to tunnel-clearing efforts to reach the trapped men.

Mine co-owner Robert Murray declined an invitation to attend the hearing, said Specter. Panel members said they would subpoena Murray to answer questions if necessary. Additional hearings are expected next month.