On the optimization of heap leaching

Although heap leaching has become established as the technology for treatment of some copper, gold, and zinc minerals, as well as its extension to the treatment of other types of minerals such as saltpeter and mine tailings, little study has been made on the optimization of this technology. Usually the operation of heap leaching is carried out until the maximum recovery has been obtained, or until observing that the concentration in the output solution of the heap exhibits no further extraction. The present study makes an analysis to determine if these criteria present the best conditions from the economic standpoint. Two variables are examined including, (1) leaching time, and (2) height of the heap, at a copper mineral treatment plant. The results of the study showed that the design (height of the heap), and planning of the operation (operational time) were interactive factors, and that maximum recovery was not necessarily the best measure of operational efficiency based on economic considerations.