The finding is part of a published report which said the state’s coal miners owed MSHA $29.2 million in delinquent fines, representing 40% of all outstanding coal fines around the country.

The report and analysis conducted by Kentucky’s Courier-Journal said many of the unpaid penalties in Kentucky and around the US were years old, some dating to 1993.

The study cited D&C Mining of Harlan County alone as owing more than $2.1 million in unpaid fines.

Millions of dollars in fines have been referred to the Department of the Treasury or the Department of Justice for collection but the Courier-Journal said much of it was likely never to be paid due to company bankruptcy and the abandonment of mines.

Fines totaling nearly $US700,000 handed down for violations relating to Kentucky’s Darby mine explosion that killed five miners in 2006 had still not been paid.

Darby had since closed and though the company was not in business, its operators were mining under the names of other companies, the Courier-Journal reported.

The Darby incident was one of a rash of fatal accidents that led to the passage of the Miner Act.

Further legislation aimed at empowering MSHA to shut down mines that were delinquent in paying fines had been brought to the fore by the latest report.

“Mine operators have less incentive to keep miners safe when fines go uncollected,” California congressman George Miller said in a statement.

“If operators can ignore fines with impunity, enforcement efforts will have no deterrent effect.”

Regionally, Appalachia and the south were spotlighted as the biggest offenders in the report, which found West Virginia second in delinquent fines with $14.7 million in outstanding penalties.

Pennsylvania ranked third with $3.2 million in overdue fines while Virginia, Tennessee, Alabama and Texas followed in the fourth, fifth, sixth and seventh spots, respectively.

Ranked only 37th in size among US states, relatively small Kentucky hosts an exceptionally high density of small coal mines, counting more than 420 state-wide.