ABSTRACTIn 1964 a waste disposal firm began dumping neutralized spent pickling liquors into an abandoned strip mine in eastern Ohio. In 1970 the disposal pit was enlarged and shortly thereafter significant water pollution problems began to occur. Highly mineralized fluids began to leak from the disposal pit into the surrounding spoil material and eventually into streams and ponds. These solutions are characterized by a low pH and excessive concentrations of dissolved solids, hardness, sulfate, chloride, nitrate, iron, fluoride, aluminum, chromium, nickel, and zinc.In addition to the contamination by steel mill wastes, acid‐mine drainage from surrounding areas degrades both surface and ground water. Acid‐mine drainage is characterized by a low pH, and high concentrations of dissolved solids, hardness, sulfate, and iron.Geohydrologic and geochemical data clearly illustrate that abandoned strip mines should not be used for the storage of toxic liquid or semiliquid materi