EMPLOYEE WAS CLEARING ROCK OFF A CONVEYER BELT. HE STARTED TO WALK BACK DOWN ON THE CATWALK AND SLIPPED ON SOME LOOSE GRAVEL. HE FELL, BRUISING HIS LOWER BACK AND BUTTOCKS. HE INITIALLY DECLIN ED MEDICAL HELP BUT THE NEXT DAY INFORMED HIS SUPERVISOR THAT HE FELT HE NEEDED TO BE SEEN BY A PHYSICIAN.