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CHARLESTON, W.Va. -- Massey Energy revealed Thursday that its corporatewide accident rates for each of the last three years were up to 40 percent worse than the company had originally reported.
Massey also disclosed what it called "mistakes" -- involving electric equipment and underground mine ventilation systems -- that occurred at its Upper Big Branch Mine prior to the April 5 explosion that killed 29 miners.
The company said none of the mistakes "contributed in any way to the accident," but were being disclosed "in the interests of transparency and accountability."
Massey said that it wrongly did not remove rail tracks from part of the mine's longwall area, leaving a potential pathway for an electrical current in place.
The company also said that Massey workers and federal inspectors moved some "non-permissible" equipment -- meaning gear that was not certified as not producing sparks that could ignite an explosion -- on that track. Massey said this may have occurred because of "confusion" about recent ventilation changes at the mine.
Massey also said that, in some places underground, air-lock doors were used instead of more permanent ventilation structures called overcasts. Air-lock doors, if left open, can cause potentially dangerous changes in underground mine airflow. Massey said MSHA approved the doors, but that their use violated the company's own "best practices."
Federal investigators have said that their probe of the Upper Big Branch explosion includes a close look at the placement and operation of the mine's air-lock doors.
Regarding its accident rates, Massey said after the explosion it "began a meticulous review of the company's accident reporting at all of its facilities." That review, Massey said, "revealed errors" in previously reported nonfatal injury rates from 2007 to 2009.
Based on nonfatal days lost injuries per 200,000 hours worked -- the standard industry measure -- Massey's 2007 rate increased from 2.05 to 2.63. The company's 2008 rate increased from 1.94 to 2.52, and its 2009 rate from 1.67 to 2.33, Massey said.
"While the company is disappointed in the lapses in its reporting procedures, it recognizes that the revised NFDL rates for the 2007, 2008 and 2009 calendar years still rank better than the industry averages for those annual periods," Massey said. "The company is working to ensure that similar reporting errors are avoided in the future and Massey remains committed to putting the safety and health of our miners first."