Operators at the Crandall Canyon mine experienced serious structural problems in the mine in March and entirely abandoned work in an area about 900 feet from where six miners remained trapped Saturday.
A memo obtained by The Salt Lake Tribune shows that mine owners were trying to work around "poor roof conditions" before halting mining of the northern tunnels in early March after a "large bump occurred . . . resulting in heavy damage" in those tunnels.
A bump or bounce occurs when the intense pressure on the coal pillars supporting the mine causes the pillars to burst, "sending coal and rock flying with explosive force," according to that National Institute for Occupational Safety and Health.
The memo indicates that mine operators knew the tremendous pressures of a mountain bearing down on the mine were creating problems with the roof, and they were searching for a way to safely keep the mine from falling in as they cut away the coal pillars supporting the structure.
"It's dangerous. Damn dangerous I would say," Robert Ferriter, now director of the mine safety program at the Colorado School of Mines and a 27-year veteran of the Mine Safety and Health Administration. "What is MSHA doing in all this? They're the ones who are supposed to catch this sort of thing." Read more...