METHANE GAS HAD ACCUMULATED IN DOME, FORMED OVER THE 36 RAW COAL FEEDER ON THE RAW COAL STOCKPILE. WHEN COAL WAS PUSHED ON TOP OF THE FEEDER, THE DOME COLLAPSED ALLOWING THE METHANE GAS TO ENT ER THE ENGINE COMPARTMENT. IT APPEARS THE METHANE WAS IGNITED FROM THE DIESEL EXHAUST CAUSING THE DOZER TO BECOME ENGULFED IN FLAME.