Deadly Mining Method Often Used
Monday, August 6, 2007; 9:27 PM
WASHINGTON -- The method of mining used at the Utah mine that collapsed Monday, trapping six miners, has a history of being disproportionately deadly, according to federal safety studies.
The Crandall Canyon mine collapse happened while miners were engaged in a method called "retreat mining," in which pillars of coal are used to hold up an area of the mine's roof. When that area is completely mined, the company pulls the pillar and grabs the useful coal, causing an intentional collapse.
It is "the most dangerous type of mining there is," said Tony Oppegard, a former top federal and state of Kentucky mine safety official who is now a private attorney in Lexington, Ky., representing miners.
According to the American Society of Safety Engineers, retreat mining requires very precise planning and sequencing to ensure roof stability while the pillars supporting the roof are removed.
The reason the practice is used is that it pays off: The last bit of coal taken from pillars is pure profit, Oppegard said. Plus, if someone violates rules during pillar removal and there is a collapse, the evidence of rule violations are gone, he said.
Retreat pillar mining is one of the biggest causes of mine roof collapse deaths, according to studies done by the National Institutes of Occupational Safety and Health.
Three of the nine roof fatalities in 2001 were from retreat mining, according to a 2003 NIOSH paper. Between 1992 and 2001, 100 miners died in roof collapses, 27 of them during retreat mining the study found.
Yet that type of mining only provides 10 percent of underground coal production, the report said, concluding "mathematically a coal miner on a pillar recovery section was more than three times as likely to be fatally injured" in a roof collapse than colleagues in other parts of a mine.
"Pillar recovery continues to be one of the most hazardous activities in underground mining," the report said. A NIOSH study six years earlier found the same thing.
Dennis O'Dell, occupational safety and health chief for the United Mine Workers of America, used to do retreat mining when he was younger.
"The only support you had basically were five breaker posts; five posts would be between you and the roof falling in," O'Dell said. "It's a pretty spooky way of mining."
But Bruce Hill, president of UtahAmerican Energy, Inc. which operates and co-owns the mine, called it a safe practice.