Heap leaching as a key technology for recovery of values from low-grade ores - A brief overview

•Heap leach technology can be more profitable when compared to conventional process routes•Successful heap leach operation requires a thorough understanding of the underlying principles for optimal operation•Heap leaching offers a promising route for the processing of many different low-grade ores and urban ore type materials

Heap leaching technology is finding increasingly widespread application to recover values from low-grade ores, especially in the gold and copper industry. The particular attractiveness of the process is the relatively low-cost recovery of the target metal at site without the need for energy intensive comminution, providing the process can be combined with a selective solution recovery technology (for example solvent extraction). However, this is contrasted with often slow and inefficient recovery, and technical issues such as poor heap permeability and post-closure stability. This paper gives a comprehensive overview of the principles of heap leaching, offers a critical analysis of the economic viability of the process and how certain technical drawbacks of the technology affect this, as well as providing a brief overview of emerging and potential future applications of the technology.