EMPLOYEE WAS OPERATING SCOOP. HE GOT OFF SCOOP TO HANG MINER CABLE. WHILE WALKING BESIDE SCOOP A PIECE OF DRAW ROCK FELL OUT BETWEEN RIB AND 1ST ROOF BOLT AND STRUCK HIM IN THE BACK. THE ROCK WAS APPROX TWO AND A HALF FOOT LONG, 17 INCHES WIDE, ONE AND HALF INCHES THICK.