EE AND OTHER EES WERE INSTALLING A PARTIAL DECK INTO THE TOP DECK OF THE 3 DECK SKAKER. A GIN POLE WAS USED TO HOIST THE DECK TO THE SHAKER. HE THOUGHT HE HAD CLEARANCE AND MOTIONED OPERATOR PULL FORWARD. WHEN DOING SO, DECK BUMPED PART OF THE STRUCTURE. HE HEARD CHAINS RATTLE. DECK RELEASED AND SHIFTED STRIKING HIM IN LEFT AND RIGHT SHOULDER