Pretreatment of copper ore prior to heap leaching

Pretreatment of copper ore prior to heap leaching includes crushing and agglomeration processes which were studied in this thesis research. Crushing is a high energy consuming process. In mining operations generally jaw and gyratory crushers are used for primary crushing and cone crushers are used for secondary crushing. During the past couple of decades High Pressure Grinding Roll (HPGR) crushers are being considered by mining companies due to lower energy consumption. In the present research copper ores (copper oxide and copper sulfide ores) were crushed by a jaw crusher and by HPGR and the products evaluated for particle damage, as well as by column leaching to determine the rate and extent of copper recovery. X-ray computed tomography analysis and laboratory column leaching experiments on copper oxide samples revealed that products from HPGR crushing have more particle damage and higher copper recoveries when compared with products from jaw crusher crushing. As expected copper recovery increased with a decrease in particle size for the copper oxide ore. However, at smaller particle sizes (below 20 x 40 mesh) copper recovery became independent of the crushing technique.