EE WAS OPERATING CMO IN NO.5 RT CROSS CUT. HE LOADED SHUTTLE CARS AND WAS IN PROCESS OF GETTING CABLE IN PLACE FOR REMAINDER OF CUT. AS HE BENT DOWN TO MOVE CABLE A ROCK FELL FROM MINING ROOF PINNING HIM TO MINE FLOOR. ROCK MEASURED 80"" X 24"" X 16"". ROCK FELL BETWEEN RT RIB AND MIDDLE ROW OF BOLTS.