WAS OPERATING THE SHEARER PREPARING TO CUT OUT AT THE HEADGATE. THE AREA WAS HIGH DUE TO ADVERSE ROOF CONDITIONS. HE WAS LOWERING THE CUTTING HORIZON TRYING TO BRING THE ROOF BACK TO NORMAL HE IGHT. A PIECE OF ROCK 22"" X 7"" X 4"" FELL OUT AND HIT THE CUTTING DRUM & BOUNCED OFF THE SHEARER & HIT HIM ON THE FOOT.