The federal agency that oversees mining safety announced plans Thursday to raise its fines amid criticism that it has been too lax in punishing mine operators who break safety rules.

The Mine Safety and Health Administration will develop rules that modernize the system under which it penalizes operators, and the change will include a hike in fines, said David Dye, acting administrator of the Labor Department agency.

"MSHA's current penalty structure is 25 years old and needs updating to strengthen incentives for compliance," Dye said in a statement. "Mine safety violations put workers at risk, so the penalties for those violations need to be serious and straightforward."

The agency has been deflecting criticism since the Jan. 2 accident at West Virginia's Sago Mine, which left 12 miners dead. Eight other coal miners have been killed on the job since then, including one who died Thursday when a roof collapsed in a Kentucky mine.

Miners' representatives were cautiously optimistic about the agency's plans to raise fines.

"We're glad to see that MSHA is taking this step, but we want to wait to see what sort of rules come out of this process," said Phil Smith, a spokesman for the United Mine Workers of America.

Smith said that in addition to the increase in fines, the government ought to make it more difficult for operators to whittle down fines on appeal. "When it gets to the review process, fines are often He cited the reduction of fines -- from $435,000 to $3,000 -- against a coal company in charge of reduced or eliminated entirely," Smith said in an interview.an Alabama mine where 13 people were killed in 2001.

There were 208 alleged violations of federal rules at the Sago Mine in the year before the accident there. The average citation was for $156, according to a congressional report released by Rep. George Miller, D-Calif., top Democrat on the committee that oversees workplace safety.

"These people were repeat offenders on serious violations," said Miller, who has urged the agency to raise fines. "We hope the secretary has gotten the message that repeat violations are unacceptable and that minimal fines are unacceptable," he said in an interview.

Labor Secretary Elaine Chao has asked Congress to raise the cap on the maximum fine it can impose on mine operators from $60,000 to $220,000. The maximum penalty was increased from $55,000 to $60,000 in 2003.

Under the Bush administration, the mine agency has levied the maximum penalty against operators 37 times, according to the report Miller released. In the five years before President Bush took office, the Clinton administration levied the maximum penalty 118 times, the report found.