THE INJURED WAS HELPING TO PUT BELT STRUCTURE ( TOP STRUCTURE FOR 48""BELT)IN THE #2 BELT LINE. WHEN HE TURNED TO PICK UP THE NEXT PIECE OF STRUCTURE TO BE INSTALLED, HIS FOOT SLIPPED ON THE WET MINE FLOOR ALLOWING HIS RT. KNEE TO TWIST RESULTING IN PAIN AND SWELLING TO HIS RT. KNEE.