HELPING CO-WORKERS SPLICE THE #4 UNIT FACE BELT, HE WAS LAYING UNDER THE BELT ON HIS STOMACH DRIVING A BELT SPLICE PIN THROUGH A NEW SET OF BELT CLIPS. THE BELT CHAIN HOLDING THE BELT STRUCTUR E SLIPPED FROM THE FRAME SLOT ALLOWING THE STRUCTURE TO FALL WITHOUT WARNING ONTO HIS BACK. THE FORCE OF THE STRUCTURE STRIKING HIS BACK RESULTED IN A HAIRLINE FRACTURE TO 1 RIB, RIGHT CHEST.