WAS REPAIRING A TAIL SHAFT OM A FEEDER. HE WAS IN A KNEELING POSITION INSIDE FEEDER USING A RATCHET TO TIGHTEN BOLT. AS HE REACHED HE FELT PAIN IN HIS ABDOMEN. HE WAS DIAGNOSED WITH AN UMBILIC AL HERNIA AND BEGAN MISSING WORK ON 5-29, WHEN HE HAD SURGERY TO REPAIR HERNIA.