EE WAS PUTTING FIRST BOLT(OUTSIDE BOLT) UP IN FACE OF #3 ENTRY.THE RIB NEXT TO EE ROLLED OFF AND HIT EE ON THE LT SIDE CAUSING RT SIDE TO STRIKE THE ROOF BOLTER.EE STATED THAT EE HAD MADE A VISUAL EXAM OF THE AREA PRIOR TO BOLTING AND THE AREA APPEARED TO BE GOOD. THE RIB WAS 5' HIGH X 16"" X 16"". EE DID NOT START MISSING WORK UNTIL 03/07/05.