Bacterial and chemical leaching pattern on copper ores of sandstone and limestone type.

Thin polished sections of copper sulphide ore were placed as an energy source in stationary cultures of wild strains and Thiobacillus neapolitanus at pH 7.5. Scanning electron microscopy revealed characteristic leaching patterns that depended on the type of leaching process and time of bioleaching. In some cases, a biological film on the ore surface was observed. Close contact between bacterial cells and ore seems necessary for leaching in some cases.