EE HAD JUST ARRIVE AT THE LONGWALL SHEARER AND WAS PREPARING TO CHANGE SOME OF THE BITS ON THE TAIL AND DRUM. HE HAD HIT A COUPLE OF THE BITS, TO LOOSEN THEM, WHEN MATERIALS FELL FROM THE MINE ROOF, STRIKING HIM ON THE HEAD, NECK, AND RIGHT SHOULDER. THE MATERIALS WERE A COMBINATION OF ROCK AND COAL AND WAS APPROX. 30"" X 36"" X 1 1/2"" THICK.