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Abstract

In the past 20 years, the energy-efficient comminution technologies, including high pressure grinding rolls (HPGR) and high speed stirred mill, have been developed and adopted in the hard-rock mining operation in order to reduce the energy consumption and improve the process performance. The combination of HPGR and stirred mill in a single flowsheet without tumbling mills has been demonstrated to be technically feasible. This research focused on the energy and cost comparisons of the existing AG/SAG ball mill circuits with two proposed comminution circuits, including an HPGR - ball mill circuit and a novel HPGR - stirred mill circuit. The main objective of this research was to advance the understanding of the potential benefits of the proposed HPGR stirred mill-based comminution circuits for low-grade, high -tonnage base metal operation. Samples and operating data were collected directly from the existing SAB/AGBC/SABC circuits to establish a base case for comparison. To support the base case, the existing circuits were fitted and simulated using a JK SimMet® model. Specific energy requirements for the proposed HPGR - ball mill circuit and HPGR - stirred mill circuit were determined from a pilot-scale HPGR and stirred mill test, in association with a JK SimMet® simulation. Results obtained from the research showed that the HPGR - ball mill circuit and HPGR - stirred mill circuit achieved a substantial reduction in energy, with considerable cost advantage over the existing SAB/AGBC/SABC circuits.