THE INJURED HAD WRAPPED A PULL CHAIN AROUND A PIECE OF CONVEYER BELT SO THAT IT COULD BE PULLED WITH A TRACK MOTOR. WHEN THE CHAIN WAS PULLED THE BELT SLIP THROUGH THE CHAIN INSTEAD OF THE C HAIN PULLING IT. THE INJURED HAD THE LOCOMOTIVE STOP PULLING THE CHAIN. HE HIT THE CHAIN WITH HIS HAMMER WHICH ALLOWED THE CHAIN TO TIGHTEN AND THE CONVEYER STRUCK HIM ON THE RT LEG.