Ore Texture, Mineralogy, and Flotation Response - A Case Study from the Nkomati Ni Mine, Uitkomst Complex, South Africa

摘要

The Nkomati Ni-Cu-Co-PGE deposit is located in the Uitkomst Complex, which is a layered mafic to ultramafic tabular intrusion situated approximately 300 km east of Johannesburg (Figure 1) and 50 km east of the eastern limb of the Bushveld Complex. It is believed to be coeval and cogenetic with the 2054 Ma Bushveld Complex. Based on ore texture, mineralogy, and associated alteration, a total of twenty-nine samples were selected from Pit 3 (Figure 2) at the Nkomati mine for laboratory scale flotation. Based on comparison of Ni grade ratios (cumulative grade in concentrate/grade in feed) to the cumulative recovery of Nickel, three flotation responses are recognized, being Good, Intermediate and Poor. Mineralogical characterization of feeds and concentrates was conducted by means of petrographic study, mineral liberation analyzer (MLA) and X-ray diffraction (XRD) analyses Based on mineralogical characterization of feed and concentrates, it was found that silicate mineralogy played a major role in Ni grade dilution whereas pyrrhotite caused major problem in terms of pentlandite liberation. Study serve to demonstrate that their is a direct link between flotation responses and ore texture, mineralogy and alteration state.