Experimental evaluation of a mineral exposure model for crushed copper ores

Copper mineral inclusions dispersed in crushed ore particles have a certain size distribution (grain-size distribution). For efficient heap leaching processes, the crushing plant should be designed and operated to crush the ore to an appropriate particle-size distribution so that copper mineral grains are exposed and can be leached. In this regard, based on the approach of Hsih, Wen, and Kuan (1995), a mineral exposure model has been evaluated to describe the extent of grain exposure as a function of particle size. Experimental evaluation of the mineral exposure model for different copper ores has been accomplished by 3D analysis of crushed ore particles using cone beam x-ray microtomography. The model evaluation with micro-CT data suggests that the extent of preferential grain boundary breakage varies both with ore type and with particle size for a given ore type.