EE WAS TRAMMING A BATTERY COAL HAULER INTO THE MINE. HE WAS TRAVELING DOWN THE 8 DEGREE MAN & MATERIAL SLOPE & WHEN HE WAS APPROX 100 FT FROM REACHING THE BOTTOM OF THE SLOPE, HE REPORTED LSOI NG POWER ON THE MACHINE, CAUSING HIM TO LOSE BRAKE & STEERING FUNCTION.AFTER LOSING POWER ON THEMACHINE,, & WITH NO STEERING FUNCTIONS HE LOST CONTROL & STRUCK THE ARCH SUPPORTS NEAR THE SLOP