Bismuth and Antimony at Olympic Dam: The Connection Between Orebody Knowledge and the Copper Refinery

The Olympic Dam operation consists of an underground mine, mineral processing plant and copper smelter and refinery. The Olympic Dam breccia-hosted Fe-oxide Cu-U-Au-Ag (IOCG) deposit is, like all ore deposits, zoned with respect to the ore, gangue and deleterious/sub-economic minerals. This zoning can also be further disrupted by significant post-mineralisation vertical faulting. Short-range variability from drill core to blast packet to production stope and mine area scale typifies the deposit. Often, geometallurgy is associated with mill throughput or flotation recovery; however, the vertically integrated operation means that the geometallurgy program must consider all minerals and elements which affect the mills, concentrator, hydrometallurgy plant, smelter and ultimately the copper refinery. During an extensive drilling and testing program in the Southern Mine Area of the deposit, an area of higher bismuth (Bi) and antimony (Sb) was identified. Using a combination of mineralogy and metallurgical testwork, the geometallurgy program predicted the levels of Bi and Sb in concentrate would significantly increase on historic levels and would likely exceed the level that the existing refinery impurity removal system could manage. Therefore, a project was initiated to add a Bismuth and Antimony Removal System (BARS) to the refinery based on ion exchange technology. This system was commissioned in 2023. This paper describes the focus of our geometallurgy program on deleterious elements which affect the refinery and copper cathode quality, discusses impacts on the refinery of elevated Bi and Sb as we began mining in the SMA, and presents early results from the new removal system.