2 CRANES & WINCH TRUCK HAD TURNED HAUL TRUCK BED UPSIDE DOWN, THEN 2 CRANES LOADED THE OVERTURNED BOX ON FLATBED TRAILER. INJURED EE THEN WAS CHECKING TO SEE IF THE TRUCK BED WAS CENTERED PROPERLY ON TRAILER. A LODGED PIECE OF EARTHEN MATERIAL CAME LOOSE COMING DOWN & STRIKING EE.