EE & CO-WORKER WERE CHANGING SPLIT SEGMENT ON DRAG CONVEYOR DRIVE. THE USED A SMALL CRANE TO REMOVE 2 SPROCKET HALVES & INSTALL THE FIRAST HALF OF THE NEW SPROCKET. THE DECIDED TO LIFT THE 2ND HALF INTO PLACE INSTEAD OF USING CRANE. INJUREDFELT A PAIN IN HIS BACK. SEVERAL WEEKS LATER HE WAS DIAGNOSED WITH A HERNIATED DISC. HE IS TO RECEIVE PHYSICAL THERAPY BEGINNING LATE APRIL.