EE WALKED OUT OF PRIMARY CRUSHER MCC BLDG. HE TURNED TO CLOSE DOORS. LONG STEEL HOOK, USED TO CLEAR CHOKES IN DEISTER FEEDER WAS STANDING IN CORNER. AS EE CLOSED DOORS, HOOK FELL HITTING EE ON TOP OF HIS HEAD. EE NOT WEARING HARD HAT. HOOK NOT STORED IN ITS NORMAL PLACE.