Stefan Robertson A Vercuil PJ van Staden and P Craven Page 471 A BACTERIAL HEAP LEACHING APPROACH FOR THE TREATMENT OF LOW GRADE PRIMARY COPPER SULPHIDE ORE SW Robertson A Vercuil PJ van Staden and P Craven MINTEK ABSTRACT Mintek is currently developing a design approach for the heap leaching of low-grade primary copper sulphide material.
Heap leaching had become a fairly sophisticated practice at least 500 years ago. Georgius Agricola in his book De Re Metallica (publ. 1557) illustrates a heap leach with a 40-day leach cycle which could pass in many ways for a modem heap leach. The Agricola heap leach recovered aluminum (actually alum) for use in the cloth dying industry .
Heap leaching is a processing technology with low operating costs and is being increasing considered for the treatment of marginal grade metalliferous ores. However heap leach facilities significantly modify the site water balance and pose a risk of process water loss to the receiving environment.
The heat is maintained in the heap by regulating the flow of solution irrigation and aeration to the heap (Neale 2012; Pradhan et al. 2008). The leachate from the heap can be treated by a number of methods e.g. solvent extraction or using ion exchange technology (Libenberg et al. 2013). The ore from the heap is then reclaimed and
In 1969 gold heap leaching began in Nevada (birthplace of modern heap leaching) and in the middle of the 20th century the United States Bureau of Mines began applying this technology. Gold and silver heap leaching first began at Cortez in 1969.
In 2011 leaching both heap leaching and in-situ leaching produced 3.4 million metric tons of copper 22 percent of world production. The largest copper heap leach operations are in Chile Peru and the southwestern United States. Although heap leaching is a low cost-process it normally has recovery rates of 60-70%.
AGGLOMERATION-HEAP LEACHING OPERATIONS IN THE PRECIOUS METALS INDUSTRY By G. E. McClelland' D. L. Pool' and J.A. Eisele3 ABSTRACT During the 19701s the Bureau of Mines investigated a particle ag-