Riding a mantrip into the mine the mantrip jumped track. He hit his shoulder against the inside compartment of the manbus injuring himself. Cause of this injury was manbus striking rib and coming to a fast stop. Compliance with rules a factor, miner proficiency a factor, protective equip. not a factor, mining equip. not a factor. EMPLOYEE DID NOT START TO MISS WORK UNTIL 8/11/06.