EE AND OTHER MECH. WERE WELDING PATCHES IN CEMENT MILL #1 SEPARATOR AND WERE TAKING TURNS WELDING AND HOLDING PATCHES. THEY HAD TO LAY ON THEIR BACK OR SIDE TO WORK. SOMETIME DURING THE DAY A METALLIC FOREIGN BODY ENTERED THE EMPLOYEE'S RIGHT EYE (EYE PROTECTION WAS USED). DID NOT SEE PHYSICIAN UNTIL 2/4/2000.