A HOISTING ACCIDENT HAS OCCURRED ONT HE MATERIAL SLOPE WHEN 4 MATERIAL CARS WHICH WERE UNCOUPLED FROM THE BONNY CAR BECAME RE ATTACHED WHEN THE HOIST OPERATOR PULLED THE BONNY CAR TO THE PITMO UTH. AS THE CARS TURNED OVER THE KNUCKLE THEY UNCOUPLED AND TRAVELED THE LENGTH OF THE MATERIAL SLOPE. NO INJURIED RESULTED FROM THIS ACCIDENT. ADDITIONAL POLICIES AND PROCEDURES HAVE BEEN IM