AS A SOMEWHAT INEXPERIENCE PREHEAT TOWER POKER, HE WAS USING A JACKHAMMER AND LONG BIT TO KNOCK SOME HARD BUILDUP OF MATERIAL OUT OF THE TOWER CHUTE. THE MATERIAL BROKE LOOSE IN THE DUCT AND HIT THE BIT CAUSING THE JACKHAMMER TO SEESAW QUICKLY & UNEXPECTEDLY. IT JERKED UPWARD & WHEN IT CAME DOWN IT HIT HIS LEFT SHOULDER FRACTURINGIT.