Application of Biohydrometallurgy to Copper Mining in Zambia: Prospects and Opportunities

Abstract

The consumption of copper worldwide has grown fast since 2000; the mining industry is increasingly faced with the necessity to process low grade ores and waste tailings, from current mining operations. The economic extraction of copper from low-grade ores requires low-cost processing methods such as biohydrometallurgy. This study looks at a general panorama of copper mining in Zambia and discusses biohydrometallurgy as a novel and economically viable process for copper extraction. It also presents future prospects of this technology in Zambia. Since early 1930s, the copper mining industry has been the economic and social pillar of Zambia with about 80% contribution to the total export earnings and about 13% Gross Domestic Product (GDP). Mineralisation in the Zambian Copperbelt is dominantly sulphide, comprising of chalcopyrite, bornite and chalcocite among others with grades of the ore deposits generally in the range of 3 - 4% copper and 0.1 - 0.2% cobalt. Huge low grade copper deposits (~0.67% Cu) which are dominantly sulphides (chalcopyrite) were recently discovered in Lumwana area in the North-western Zambia and are currently being exploited. Reports show that more than one billion tons of ore (c.2.7% Cu) has so far been mined from the mines on the Copperbelt Province of Zambia and conservative estimates suggest that a further two billion tons await exploitation. This provides considerable opportunities for further exploration and mining in Zambia. However, there is currently no commercial copper processing plants in operation on a large-scale in Zambia via biohydrometallurgical process. In order for Zambian mining industry to considerably improve recoveries at inherently lower capital cost, there is need to focus effort on research in this innovative technology and its application.