CHARLESTON, W.Va. – A federal official says a handheld meter found deep inside the Upper Big Branch mine detected explosive levels of methane before a blast killed 29 miners.
The handheld meter is the first piece of equipment showing explosive levels of methane in the mine at the time of the April 5 blast. The Mine Safety and Health Administration's Kevin Stricklin says the device detected 5 percent methane in the mine's atmosphere that day.
Methane only explodes when it makes up 5 percent to 15 percent of the atmosphere.
Richmond, Va.-based Massey Energy Co. the mine's owner, has said that high methane levels just prior to the explosion overwhelmed safeguards.
A preliminary report issued by MSHA in April blamed methane and coal dust for the explosion.