EE WAS STANDING NEAR A FLAT CAR LOADED WITH 60"" 500' OF CONVEYOR BELTING THAT WAS HOISTED UP ON ITS END IN ORDER. TO PLACE IT ON THE SUPPLY CAGE ELEVATOR. ONE OF THE CHAINS BEING USED TO SECUR E SEVERAL OF THE LAYERS OF BELTING ONTO THE CAR BROKE CAUSING APPROX. 40' OF THE BELTING TO SLIDE DOWN OFF THE CAR STRIKING THE EE AND KNOCKING HIM DOWN.