Bioprocessing of nickeliferous sulphidic wastes from mining activities

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We propose to investigate the amenability to bio-processing of a metallurgical waste stream produced by the Xstrata Nickel smelting operations in Sudbury, Ontario, namely nickeliferous pyrrhotite concentrate. This is an iron-sulphur mineral (approx. stoichiometry Fe1-xS) that is rejected because it is unsuitable for smelting. Large quantities are stored in ponds under water. The rejected pyrrhotite contains about 1%wt of nickel in solid solution which is lost from Xstrata's potential production capacity and poses an environmental risk by having an enormous potential for acid mine drainage. The concept is the development of a process using an industrial residue as the feed material to recover a valuable resource (i.e., nickel) and reduce the toxicity of the residue. Apart from the feed being a Canadian resource, no additional mining is required. We propose to assist the development of new technology to treat this waste stream by a low-cost process. That is by bioprocessing based on recent advances in biotechnology in the areas of copper and gold extraction, but not on nickel, by employing bacterially assisted leaching. Such technology will open the road for widespread bio-leach operations in Canada, and revitalize the minerals economy by low-cost and environmentally responsible processes. The project brings together five partners, namely Xstrata Nickel, the Ontario Centers of Excellence, the Center for Excellence in Mining Innovation and NSERC, as funding agencies and the University of Toronto as the executioner of the research. The hydrometallurgy, bioremediation and metabolic modelling groups of the University of Toronto will team-up and engage in an interdisciplinary research effort. Three MASc students, one PDF and at least two undergraduate students will be trained in a collaborative environment and state-of-the-art bioprocessing facilities over a period of two years.