EMPLOYEES WERE CHANGING SHANK PROTECTORS ON PIT LOADER BUCKET. THE LEFT SIDE WAS STUCK SO THEY HAD TO HIT IT WITH A 8 LB SLEDGE HAMMER. A PIECE OF METAL BROKE OFF THE SHANK PROTECTOR AND STRUC K EE IN THE LEFT LEG CAUSING A PUNCTURE WOUND IN THE FRONT OF HIS THIGH AND THE METAL LODGED UNDERNEATH THE SKIN ON THE BACK OF HIS LEG.