EE IS STATING HE AND ANOTHER EE WERE WORKING TO CHANGE ONE OF THE TRACKS ON A D11 CAT DOZER. INJURED EE WAS STRUCK BY METAL FRAGMENT IN THE CHEST AREA WHEN THE OTHER EE STRUCK THE MASTER LINK WITH A 17# HAMMER. EE WENT TO ER ON 5-2-03, SENTTO A SURGEON PM 5/5 AND HAD METAL PIECE REMOVED ON 5-6-03