In-situ leaching recovery of copper: what’s next?

Abstract

The recovery of mineral and metal values by solution mining has been practiced for centuries. What appears at first glance to be a simple, empirical technique, is in actuality a very complicated process involving a large number of critical parameters that encompass several scientific and engineering disciplines. Hydrometallurgy, hydrology, geology and geochemistry, rock mechanics, chemistry, and environmental engineering and management are a few of the specialties utilized by modern operators.Solution mining is conveniently divided into three main categories: heap leaching, dump leaching, and in situ leaching. In situ leaching (ISL) involves the application of a specific lixiviant to dissolve en masse minerals within the confines of a deposit or in very close proximity to its original geologic setting. Currently there is considerable interest in applying ISL technology to recover copper. Substantial research and engineering effort is being expended to recover copper from oxide ores. However, the greatest potential for copper ISL extraction remains with the deep seated deposits that would otherwise be left unmined by conventional methods.This paper highlights some historical aspects of copper in situ leaching, and also reviews some commercial and experimental projects involving both oxide and sulfide deposits. In addition, large whole-core leaching experiments using a copper oxide ore will be described. This work has provided better understanding of the physical and chemical factors associated with the in situ leaching response.