EE WAS BLOW PIPING THE FEED CHUTE TO THE 3/W CRUSHER. SOME MUCK FELL AND STRUCK THE PIPE. HIS LEFT HAND WAS ON THE SHUT-OFF VALVE AND WHEN THE MUCK FELL, IT PUSHED THE PIPE BACK. HIS HAND STRU CK THE AIR CYLINDER, FRACTURING IT ABOVE HIS RING FINGER. RETURNED FULL DUTY.