What caused mine explosion in West Virginia?[ Wed, 7 Apr 2010 19:23:58 GMT ]Why did the explosion at the Upper Big Branch mine in West Virginia happen? Forensic teams will be investigating that issue over the next year or so, looking to see if safety regulations need to be updated. at there's no way to be certain methane caused the explosion — coal dust is everywhere in mines, and can ignite violently. Standard safety practice dictates that mines be "rock dusted" so that at least 65 percent of all dust in the mine is made up of harmless limestone.