EMPLOYEE HAD FINISHED ROOF BOLTING & WAS PULLING BACK ROOF BOLTER CABLE WHEN A ROCK APPROX. 3'X 3'X 2"" FELL OUT BETWEEN THE RIB & RIB PIN & STRUCK HIM ON THE LOWER BACK. HE RECEIVED A PUNCTURE WOUND TO HIS LOWER BACK AND 5 SUTURES WERE REQUIRED TO CLOSE THE WOUND.