EE HAD DUMPED A LOAD IN A 10 TON DUMP TRUCK HE WAS OPERATING. CO-WORKER NOTICED A PIECE OF PLASTIC CONDUIT STUCK IN THE TAILGATE. EE UNLATCHED THE TAILGATE & WENT TO THE REAR OF THE TRUCK TO HELP REMOVE CONDUIT. HE WENT TO HELP OPEN THE GATES SO CO-WORKER COULD REMOVE CONDUIT. WHEN THE CONDUIT CAME OUT, THE TAILGATE CLOSED, PINCHING EE'S RT. RING FINGER.