A preliminary investigation into the feasibility of a novel HPGR-based circuit for hard, weathered ores containing clayish material

The paper reports the progress of a research project using rock samples from a large copper–gold mining project. The orebody contains a mixture of hard rock, softer material, and clays (sericite), in proportions that are expected to vary throughout the mine-life. The feasibility of a novel comminution circuit, using an autogenous (AG) mill/scrubber and parallel trains of cone crushers and high-pressure grinding rolls (HPGR) is being investigated. The process enables the application of energy-efficient HPGR to base and precious metal hard-ores containing clay, which are usually processed using SAG mill circuits.The work presented in this paper involved laboratory testwork including pilot HPGR testing, and modelling and simulation of both the HPGR-based circuit and an equivalent SAG-based circuit. The preliminary analysis reported herein includes a comparison of the energy consumption of both circuits; complete operating and capital cost comparisons will be reported in a future paper.

Research highlights
► The development of a more rigorous approach to testing HPGR circuits.
► The development and evaluation of a novel HPGR circuit for clayish ores.
► Potential for significant energy and steel savings with a novel HPGR circuit.
► The demonstration of the benefit of scrubbing in HPGR circuit for screen efficiency.
► Demonstration that partially truncated HPGR feed can be effectively processed.