EMPLOYEE WAS ROOF BOLTING ON UNIT 2. HE WAS IN THE PROCESS OF REPOSITIONING THE ROOF BOLTER BOOM FOR THE NEXT HOLE. AS HE DROPPED THE ATRS THE CANOPY FLIPPED A ROOF BOLT STEEL AND THE STEEL ST RUCK THE EMPLOYEE ON THE LEFT SIDE OF THE HEAD. HE WILL BE INSTRUCTED TO ALWAYS STORE THE ROOF BOLT STEEL IN AN AREA CLEAR OF THE ATRS AND CANOPY. HE STARTED MISSING TIME ON 12/30/03.