Interrelationship of hydrology, microbial colonisation and hydrometallurgy in a simulated chalcopyrite heap leach

Includes bibliographical references (leaves 104-115).Chalcopyrite is the most abundant primary copper sulphide mineral found worldwide. As copper grades of ores available for extraction decrease, heap bioleaching is gaining interest as a potential operating alternative to traditional methods of roasting and smelting. The efficiency by which bacteria assist leaching chalcopyrite is governed by their interaction and association to the sulphide mineral in the ore. While both planktonic and mineral-associated micro-organisms contribute to the bioleaching of mineral sulphides through the oxidation of ferrous iron little information exists as to their ability to adhere and leach low grade chalcopyrite ore. This study was undertaken to determine the association of defined and mixed microbial species on a chalcopyrite concentrate and a chalcopyrite ore. At. ferrooxidans, At. caldus, At. thiooxidans and L. ferrooxidans were grown in pure culture and used to investigate the mineral-microbe association within defined experimental parameters of two experimental operations