A BLAST HOLE DRILLER EMPLOYED BY INDEPENDENT CONTRACTOR GENERAL DRILLING WAS MAKING A REPAIR TO THE MUD FLAP ON HIS DRILL TRUCK. USING A PUNCH TO MAKE A HOLE IN THE MUD FLAP, HE MISSED AND HIT HIS LEFT HAND WITH HIS HAMMER. THE ACCIDENT OCCURRED IN THE QUARRY SHOP. HE WAS TREATED AND RELEASED AT A CLINIC. THE DOCTOR REPORTED ""NO PERMANENT IMPAIRMENT"". HE WAS RELEASED TO RETURN 9/29