One miner is dead and another missing after a roof collapse in a Harlan County (search) coal mine, and rescue crews are trying to dig their way through a wall of fallen rocks, authorities said.

Paris Charles, executive director of the Kentucky Office of Mine Safety and Licensing (search), said the body of one of the miners was recovered about 5:30 a.m. EDT. "There is an ongoing operation to find the other missing miner," he said. "At this point, we are calling this a rescue operation, until something tells us different."

A section of mine roof 20 feet wide, 20 feet long and 11 feet high collapsed without warning around midnight, Charles said. The two miners were part of a crew of about eight men who were working in the portion of the mine, performing what is called retreat mining in which coal pillars that support the roof are removed.

"It is one of the more dangerous aspects of mining," he said.

Kentucky State Police (search) were called to the scene to help with crowd control as anxious relatives sought information, said Trooper Walt Meachum, spokesman for the state police post in Harlan.

Authorities haven't released the names of the miners.

Charles said the roof fall occurred in the Stillhouse Mining Mine No. 1 just outside Cumberland. Stillhouse is owned by Black Mountain Resources (search), a division of Cumberland Resources. The mine has been in operation since 1999, and has 73 employees.

Miners who were working in the same area reported that they had no warning that the roof was about to give way, Charles said. Normally, miners would hear bumping noises and see smaller rocks falling before a major roof collapse.

Charles said rescue crews don't know whether the missing miner is beneath the fallen rocks or behind them.

"We always hope for the best," he said. "I can't really say one way or the other."

Crews were setting up steel arches Thursday morning to make the mine safe for would-be rescuers.

Charles he expects rescue crews to reach the missing miner by late Thursday or Friday morning.

If the miner is trapped behind the fallen rocks, Charles said "in all likelihood" he would have enough oxygen to survive until rescue crews arrive.

The confirmed death in Harlan County brings to 11 the number of coal miners who have been killed in coal mines in the United States so far this year, according to the U.S. Mine Safety and Health Administration (search). Two of those were in Kentucky.

The federal government's tally of mine deaths in the United States last year was 55, and 28 of those deaths were coal-related.

West Virginia led the nation in mine deaths last year with 12. Kentucky, with six miners killed, was second.

Industry representatives attribute the reduction in fatal accidents to increased emphasis on safety by companies and regulatory agencies, and better equipment. Jobs in mining have also decreased significantly in recent years, falling from 252,400 in 1995 to 202,700 in 2003 in all mining categories except oil and gas, according to the National Mining Association's (search) Web site.