OUR CREW WAS RELINING THE STD. CONE. EE WAS HOLDING A BAR FOR A COWORKER TO HIT WITH A SLEDGE HAMMER. EE WAS NOT STANDING BACK FAR ENOUGH & GOT IN THE LINE OF THE COWORKER'S SWING. EE WAS HIT BY THE SLEDGE HAMMER ON THE RIGHT SIDE OF HIS BACK. HE SOUGHT MEDICAL ATTENTION.