A BULK TRUCK BACKED IN TO BE LOADED. EMPLOYEE STEPPED ONTO TOP OF TRUCK TO OPEN HATCH; DRIVER NOT KNOWING THIS, DECIDED TO PULL OUT & REPOSITION THE TRUCK MORE SQUARELY IN LINE WITH SPOUT. EMP LOYEE SCRAMBLED TO REAR OF TRUCK, DESCENDED LADDER & JUMPED THE REMAINING 2' TO THE GROUND & WAS STOPPED BY THE LIFE LINE JUST AS HIS FEET MADE CONTACT WITH THE GROUND, BRUISING HIS ABDOMEN.