Background: Leaching of copper has been improved in many instances by the inclusion of bacteria in the leaching solution. If such a system could be applied to extracting copper from the many mine dumps of low grade ore that exist in South Australia, it might reduce leaching costs to a point where these dumps could easily be treated economically. Objective: The work was aimed at determining the feasibility of using bacteria to increase the rate of dissolution of copper when leaching dump material. Summary of Results: Bacterial leaching tests were conducted on copper-bearing dump materials from the Wallaroo and Moonta mines areas, using bacteria obtained from mine shafts adjacent to the dumps. In an initial test, 20% of the copper contained in slime dump material was leaching in 126 days. The results of subsequent tests were inferior, due probably to degeneration of the bacterial culture. Bacteria of the Thiobacillus type could not be cultured from the mine waters sampled. However, it is now considered probable that such bacteria were present in the ore, and that the similarity of results between supposed bacterial leach and control samples was due to the same bacteria being present. Extractions of up to 40% were obtained, but it was not proven that any bacterial action promoted this extraction. Conclusions and Recommendations: It is considered that the work shows the feasibility of using bacteria to enhance the leaching of copper from mine dump material, and further work is warranted to define the bacteria species responsible and to determine the ideal environment for their development. When these aspects have been established, the optimum conditions for extraction should be evident. However, work of this nature is being conducted at the University of NSW, and pending the outcome of this, further wrok on the project should be postponed.