In-situ study of texture-breakage coupling in a copper ore using X-ray micro-CT

Abstract

As the mining industry continues to seek greater energy efficiency, it needs more effective characterization of ore material as it progresses from mine to mill. The energy cost of ore mineral liberation, for example, is critically dependent on management of rock breakage from blasting to comminution. The study reported here presents a quantitative method for 3D characterization of ore texture and breakage based on X-ray micro-CT and in-situ micromechanical test. A porphyry copper ore is studied from its initial mechanical failure to the onset of fragmentation. This work integrates a quantitative ore textural analysis with 3D mapping of both the dominant minerals and micro-porosity in the ore sample. It enables us to show, as the fractured ore is still under loading, that internal breakage of feldspar grains dominates grain boundary fracturing. We discuss how the microporous regions, mostly found in hydrothermally altered plagioclase, may act as a weakening factor leading to the dominant breakage of plagioclase. We measure quantitatively and discuss how size reduction, ore texture and breakage characteristics control the degree of liberation of Cu minerals. Combining characterisation of ore texture with breakage in 3D could provide much needed insights for achieving more energy-efficient comminution and optimal liberation of critical minerals.