WHILE CRAWLING UNDERGROUND, HIS KNEE PAD ROLLED TO THE SIDE AND HIS LEFT KNEE CAME DOWN ON A PIECE OF ROCK. HE CONTINUED TO WORK BUT AFTER SOME TIME HE STILL HAD DISCOMFORT IN THE LEFT KNEE. AFTER SEEKING MEDICAL TREATMENT AND HAVING TESTSDONE IT WAS DETERMINED HE HAD A MANICUS TEAR IN THE KNEE WHICH REQUIRED SURGERY. EMPLOYEE THEN WENT OFF WORK ON 1/31/02 TO HAVE SURGERY DONE.