EE WAS STANDING NEAR BY WHEN ANOTHER EE WAS USING A 8 LB HAMMER TO KNOCK THE BUSHING DOWN IN THE HUB OF THE KELLY DRIVE ON THE DM-25 DRILL. A SMALL FRAGMENT APPROX 1/8"" IN SIZE CAME OFF THE EA R OF THE BUSHING AND STRUCK HIM IN THE STOMACH. EE USING THE SLEDGE HAMMER SAID HE COULD ONLY SWING ABOUT 6 INCH, WHICH IS VERY LITTLE FORCE. THEY THINK EAR WAS ALREADY CRACKED.