Coal mining accidents sound like the tragedy of a bygone era, but an accident Wednesday night that trapped a nine-man crew about 300 feet below ground is a grim reminder of how dangerous the job can be.
The U.S. Mine Safety and Health Administration reports there have been 17 mining-related fatalities in 2002, and that fatalities have increased every year for the past three years.
Nine men were trapped in a mine Wednesday night when they punched through the wall of an abandoned neighboring mine that held as much as 60 million gallons of trapped groundwater. The men radioed news of the accident to a second crew, who were able to wade out of the mine through water that was up to their necks.
Rescuers heard the trapped men banging on a pipe around 3 a.m. Thursday, and have monitored them since then using seismic technology. Rescuers estimate it will take 18 hours to drill a 36-inch-wide hole down into the mine to extract the men.
Keeping a Distance
Regulations require companies to maintain a distance of at least 200 feet between mines. At a certain distance, set by regulators and relative to the site, miners must begin drilling a 40-foot-long hole ahead of themselves to prevent just the sort of the accident that happened Wednesday night.
There was no immediate explanation for the Somerset, Pa., accident. Pennsylvania Department of Environmental Protection Secretary David Hess hinted today that Black Wolf Coal Co.'s map might have been inaccurate but said further investigation was needed. Rodney Brown, a spokesman for the U.S Mine Safety and Health Administration, said an investigation would take about a month.
The nine-man crew was performing a common technique called room-and-pillar mining: A machine called a continuous miner, a mechanized drumhead equipped with drill bits, digs parallel paths through the earth, each about 18 feet wide and as much as 3,000 yards deep. These "rooms" are separated by 50- to 100-foot wide pillars to support the roof of the mine. Cross-cuts between rooms are made every couple hundred yards.
As the machine plugs along, it grinds the coal and drops bits into a pan, where they are gathered and carted by an electric shuttle to a conveyor belt. Coal is brought to the ground surface by an elevator, then shipped by truck and train to power plants around the country.
"It's a very methodical process," said Karl Lasher, a spokesman for Pennsylvania's Department of Environmental Protection.
Digging a Mine
A nine-man crew works each mine: One worker to operate the continuous miner and one to assist, two drivers to steer the shuttles, two bolt-men to keep the ceiling aloft, one supply person, one mechanic and one supervisor.
As a crew retreats after mining a room, it turns the continuous miner on the supporting pillars and begins the careful process of collapsing the roof to collect the remaining coal.
The Somerset mine was a smaller operation with only 32 employees on site, but some larger mines have as many as 600 people. Coal mines can go 800 feet deep and cover as much as 25 square miles underground. The bituminous coal mined in western Pennsylvania largely is burned for steam and helps supply 60 percent of the nation's electricity.
Most fatalities occur when the roof of a mine collapses unexpectedly, though this year there has been a rash of electrical accidents, said Tim Baker, an assistant to the director of the United Mine Workers of America. Methane gas, which becomes explosive at concentrations of 5 to 15 percent, also creates a serious danger. Baker said flooding accidents such as the incident in Somerset County, Pa., are uncommon.