CONTRACTOR WAS STANDING ON RIGHT FRONT TIRE OF LOADER WITH HIS KNEES AGAINST THE FENDER FOR SUPPORT IN PREPARATION OF RECEIVING A 75 LB HOIST CYLINDER PIN, WHICH WAS BEING HANDED TO HIM. HE SE T THE PIN ON THE FENDER, WHICH BROKE OFF CAUSING HIM TO LOST HIS BALANCE AND FALL 9' TO THE GROUND LANDING ON HIS HEAD, BACK AND SHOULDER. CUT FINGER (6 STITCHES) & STRAINED BACK MUSCLES.