EE WAS STANDING ON THE LEFT SIDE OF THE MINER TO HELP THE ROOF BOLTER WHEN IT WAS TIME TO INSTALL A VENTILATION TUBE WHEN THE RIB FELL AGAINST THE VENTILATION TUBE AND THEN STRUCK HIM CATCHING HIM BETWEEN THE RIB AND THE MINER. THE PIECE OF RIB HAD BROKEN OFF APPROX 4' FROM THE BOTTOM AND MEASURED 10' X 4' X 16"" THICK