As the investigations progress officials say that a lack of protective measures, worn out drill bits and a presence of methane gas is what contributed to the mine blast which killed 29 coal miners last April. The West Virginian mine being investigated in Montcoal was an Upper Big Branch mine.
The U.S. Mine Safety and Health Administration and the U.S. Department of Labor officials released their preliminary findings of the investigation. These contradicted the statements given by mine owner Massey Energy according to whom a crack in the floor caused major leak of methane into the mine.
They claimed that the disaster could not be stopped unfortunately the investigations by the MSHA officials seems to prove otherwise. A water-spray system that helps suppress explosive coal dust wasn't functioning properly, and sparks from worn carbide bits on a piece of equipment known as a longwall shearer likely ignited gases that had reached explosive levels according to their report.
The worn drill bits of the shearer could have made a spark that would have ignites the very small amount of methane that was present. It would have then fueled the massive coal dust explosion in which the miners were killed. The representatives of Massey did not at present agree with the working theory of the MSHA.