EMPLOYEE BENT DOWN TO CHECK THE OIL LEVEL IN THE TRANSFER CASE OF THE COAL HAULER HE WAS OPERATING AND EXPERIENCED PAIN IN HIS RIGHT KNEE. THE COAL HAULER WAS PARKED ON A FLAT, DRY, SMOOTH SUR FACE. AFTER SEEKING MEDICAL OBSERVATION BY A DR HE WAS RETURNED TO WORK AT 100% CAPACITY. ON 4/1/01 & ON 5/16/01 HE SOUGHT MEDICAL ATTENTION. DR REPORTS A TORN MENISCUS LIGAMENT REQUIRE SURGE