EMPLOYEES WERE ROLLING DRAG CHAINS ON THE BUCKET OF A 1370 DRAGLINE. THEY WERE HOOKING UP THE DRAG CHAIN CLEVIS AND WHILE LIFTING THE CLEVIS PIN INTO POSITION, EE HURT HIS BACK. THE PIN WAS 6"" IN DIA BY 18"" LONG AND WEIGHS ABOUT 150 LBS. TWO EE'S LIFTED THE PIN FROM THE GROUND TO THE SHOULDER LEVEL. EE'S SHOULD HAVE USED AVAILABLE BOOM TRUCK. 1ST DAY MISSED 4-3-02.