Federal mine safety officials are seeking the permanent reinstatement of a miner who claims he was fired for complaining about dangerous working conditions at Massey Energy mines, including the mine where 29 men were killed.

The federal Mine Safety and Health Administration also is seeking back wages for Ricky Lee Campbell, a $20,000 civil penalty against the Richmond-based company and other unspecified relief. MSHA filed its complaint with the federal Mine Safety and Health Review Commission on Wednesday.

MSHA chief Joe Main said Campbell was fired April 23 after talking to reporters about safety issues at Massey's Upper Big Branch mine. Campbell had briefly worked at the Raleigh County mine and was working at another Massey operation the day of the April 5 explosion.

Campbell's comments were made during a television interview two days after the explosion. Campbell claims he also complained about mechanical problems with a piece of heavy equipment he operated at Massey's Slip Ridge Cedar Grove Mine.

Massey spokesman Jeff Gillenwater disputed the allegations.

"As the facts in this matter come to light, it will be very clear why Mr. Campbell was terminated and that his termination had nothing to do with him raising concerns about Massey Energy's safety practices," Gillenwater said. "All Massey Energy members are encouraged to raise any concerns and suggestions about safety."

Wednesday's filing marks the second time MSHA has filed actions on Campbell's behalf. In June, an administrative law judge ordered Massey to temporarily rehire Campbell after MSHA filed a complaint.

"While this case is being tried, we want to send a clear message that operators who punish employees for expressing concerns about safety conditions should be held accountable for their actions," Main said in a prepared statement.

Federal and state investigators are still trying to determine what caused the Upper Big Branch explosion, the worst U.S. coal mining disaster in 40 years.