A SEMI COAL TRUCK HAD GOTTEN STUCK ON THE COAL PILE. EE HOOKED A 12' X 3/8"" CHAIN TO A D-8 DOZER TO PULL THE TRUCK OUT. AFTER THE DOZER OPERATOR TIGHTENED THE CHAIN, EE BACK AWAY APPROXIMATELY 35'. AS PRESSURE WAS THEN APPLIED, THE HOOK ON THE CHAIN BROKE, SENDING THE 1 1/2"" FRAGMENT FLYING AND STRIKING EE ON THE BRIDGE OF THE NOSE. HE HAD 2 LACERATIONS AND A FRACTURED NOSE.