A small methane gas fire that wasn't doused because of broken equipment sparked a massive coal dust explosion that killed 29 miners at Massey Energy Co.'s Upper Big Branch mine, the U.S. Mine Safety and Health Administration said Wednesday.
Massey records and evidence found deep inside the southern West Virginia mine points to poor maintenance in the deadliest U.S. coal mine explosion since 1970, MSHA officials told reporters during a conference call. The agency expects to finish its probe in two to three months, but said it wanted to issue preliminary findings.
Those findings include worn and broken equipment investigators believe contributed to the initial fire and made it impossible to put out, and poor housekeeping that allowed excessive amounts of explosive coal dust to coat much of the mine just before the April 5 blast.
"We've always taken a position that all explosions are preventable," MSHA administrator Kevin Stricklin said. "We still stand by our point."
Investigators believe the explosion started when badly worn teeth on a 1000-foot-wide mining machine created a spark that ignited as little as 13 cubic feet of methane.
"It would be like a burst or a burst of flame," Stricklin said.
Tests that Massey resisted showed that some of the machine's 48 water sprayers for controlling dust and dousing sparks weren't working at the time.
"There are a number of sprays that are missing. It almost looks as if a garden hose has water coming out of it and the other sprays do not have water coming out of them," Stricklin said.
Richmond, Va.-based Massey stuck to its stance that a massive influx of natural gas from deep below the mine rushed in through a crack so quickly it overwhelmed safeguards.
"We do not currently believe that there were issues with the bits or the sprays on the shearer that contributed to the explosion," general counsel Shane Harvey said. "We likewise do not believe that coal dust played a meaningful role in the explosion. We currently believe the mine was well rock dusted."
MSHA cited Massey on Nov. 10 for impeding its investigation after mine employee Charlie Bearse refused to help supply water to test the sprayers.
Stricklin painted a horrifying picture of the moments leading up to the blast: At least two miners near the fire apparently alerted co-workers who shut off the equipment. They made a harrowing dash away from the flames, hurdling the bottoms of hydraulic jacks holding up the mine's roof. They ran perhaps as long as 90 seconds, covering about 400 to 500 feet.
"I really don't know what they're thinking at the time. I just know that they know they're in a bad issue and they're trying to get out of there as quickly as possible," Stricklin said.
They didn't make it. When the flames ignited coal dust, it unleashed a blast that killed everyone, including co-workers more than a mile away.
"It was a small amount of methane when it began," Stricklin said.
The Associated Press reported in September that handwritten inspection logs filled out by Massey employees before the explosion showed eight of the mine's conveyer belts had excessive amounts of coal dust before the explosion. MSHA cited those reports and dust samples taken after the blast that showed excessive coal dust throughout a wide area of the mine.
The worn teeth, which are more prone to sparking, and broken sprayers were not mentioned as required in a report on an examination conducted about 20 minutes before the explosion, Stricklin said. That report noted only that there was enough air blowing across the fact to ventilate the area and that no methane had been detected.
Massey records suggest production at the mine was lagging that day. Stricklin said records show the longwall broke down about 11 a.m. and wasn't running until as late as 2:15 p.m.
Investigators are still trying to determine whether the mine's ventilation system was working properly at the time.