The geology, geochemistry, mineralogy and mineral beneficiation of platinum-group elements

Published for the Geological Society of Cim as Cim Special volume 54 by Canadian institute of mining, Metallurgy and petroleum. Contents. Preface iii. L.J. Cabri. Sample Preparation and Bulk Analytical Methods for Pge. E.L. Hoffman and B. Dunn. The Platinum-Group Minerals. L.J. Cabri. Ternary and Quaternary Phase Systems with Pge. E. Makovicky. Platinum-Group Element Geochemistry of Mafic and Ultramafic rocks. J.H. Crocket. The Aqueous Geochemistry of the Platinum-Group Elements with. Applications to Ore Deposits. S.A. Wood. A review of Rhenium-Osmium Isotope Geochemistry of Platinum-Group. Minerals and Platinum Mineralization. K.H. Hattori. Sudbury PGE Revisited: Toward an Integrated Model. C.E.G. Farrow and P.C. Lightfoot. Magmatic-Hydrothermal Cu- and Pd-rich Deposits in Gabbroic Rocks. from North America. D.H. Watkinson, M.J. Lavigne and P.E. Fox. Contact-type and Magnetitite Reef-type Pd-Cu Mineralization in Ferroan. Olivine Gabbros of the Coldwell Complex, Ontario. C.T. Barrie, A.D. MacTavish, P.C. Walford, R. Chataway and R. Middaugh. Platinum-Group Element Mineralization in Paleoproterozoic Basic Intrusions. in Central and Northeastern Ontario, Canada. R.S. James, S. Jobin-Bevans, R.M. Easton, P. Wood, J.L. Hrominchuk, R.R. Keays. and D.C. Peck. Stratiform and Contact-type PGE-Cu-Ni Mineralization in the Fox River Si. and the Bird River Belt, Manitoba. D.C. Peck, R.F.J. Scoates, P. Theyer, G. Desharnais, L.J. Hulbert and. M.A.E. Huminicki. Platinum-Group Element Deposits in the Bushveld Complex, South Africa. R.G. Cawthorn, R.K.W. Merkle and M.J. Viljoen. Platinum-Group Element Distributions in the Rustenberg Layered Suite. of the Bushveld Complex, South Africa. S.-J. Barnes and W.D. Maier. Platinum-Group Element Mineralization in the Stillwater Complex, Montana. M.L. Zientek, R.W. Cooper, S.R. Corson and E.P. Geraghty. Platinum-Group Element Mineralization of the Great Dyke, Zimbabwe. T. Oberthür. Platinum-Group Element Mineralization in Layered Intrusions of Northern. Finland and the Kola Peninsula, Russia. T.T. Alapieti and J.J. Lahtinen. The PGE Mineralization of Disseminated Sulphide Ores of the. Noril’sk-Taimyr Region. M.Z. Komarova, S.M. Kozyrev, O.N. Simonov and V.A. Lulko. PGE Mineralization of the Monchegorsk Layered Mafic-Ultramafic Intrusion. of the Kola Peninsula. A.V. Dedeev, T.N. Khashkovskaya and A.S. Galkin. Komatiite-associated Ni-Cu-(PGE) Deposits: Geology, Mineralogy, Geochemistry, and Genesis. C.M. Lesher and R.R. Keays. Magmatic Ni-Cu-(PGE) Sulphide Deposits in China. M.-F. Zhou, Z.-X. Yang, X.-Y. Song, R.R. Keays and C.M. Lesher. Platinum-Group Elements in the Palaeogene North Atlantic Igneous Province. J.C.Ø. Andersen, M.R. Power and P. Momme. Alaskan-type Complexes and Their Platinum-Group Element Mineralization. Z. Johan. Platinum-Group Minerals (PGM) in Placer Deposits. T.W. Weiser. The Mineralogy and Behaviour of PGM During Processing of the. Noril’sk-Talnakh PGE-Cu-Ni Ores. S.M. Kozyrev, M.Z. Komarova, L.N. Emelina, O.I. Oleshkevich, O.A. Yakovleva. D.V. Lyalinov and V.I. Maximov. The Mining and Beneficiation of South African PGE Ores — An Overview. R.K.W. Merkle and A.D. McKenzie. A Review of the Beneficiation and Extractive Metallurgy of the. Platinum-Group Elements, Highlighting Recent Process Innovations. S. Cole and C.J. Ferron. Authors’ Biographies. China is self-sufficient in nickel, but has a shortage of copper and precious metals: platinum-group elements (PGE) and gold. Over 98% of China's PGE resources are produced from magmatic Ni-Cu-(PGE) sulphide deposits. Currently, the majority of the PGE are produced as by-products from the Jinchuan Ni-Cu mine in NW China with minor amounts produced from the Hongqiling deposit in NE China and the Yangliuping deposit in SW China. The Jinchuan deposit contains 85% of China's Ni reserves (Tang et al., 1994; Tang, 1996; Liang et al., 1998) and is relatively well known in the western literature (Chai and Naldrett, 1992a, 1992b; Tang, 1993; X.-Z. Yang et al., 1994a, 1994b; Barnes and Tang, 1999), whereas, very little has been published on the other deposits. Chinese geologists have carried out extensive research on the sulphide deposits and have classified them according to their host rocks (X. Yang et al., 1993; Liang et al., 1998). The deposits have traditionally been interpreted to have formed from mafic-ultramafic magmas that segregated sulphides at depth (Tang, 1999), however, there is an outstanding need for a re-evaluation of the genesis of these deposits within the context of research done on other deposits of this type. Magmatic deposits hosted within large layered intrusions, such as Stillwater and Bushveld, are not known in China. Instead, most of the sulphide deposits are hosted by small mafic-ultramafic bodies, some of which are poorly differentiated, olivine-rich cumulate bodies similar to those in Thompson, Manitoba (Zurbrigg, 1963); some of which are strongly differentiated, non-cumulate gabbro/peridotite bodies similar to weakly-mineralized bodies in the Cape Smith Belt, northern Québec (Giovenazzo et al., 1989; see also Lesher and Keays, this volume). Several Ni-Cu(PGE) sulphide deposits are associated with the Late Permian Emeishan large igneous province in SW China and several groups of mafic intrusions with significant sulphide deposits are associated with Late Permian magmatism in northern China. These deposits are poorly understood in terms of their geological settings, but their host intrusions and associated volcanic successions suggest links with mantle plumes, similar to those in the Noril'sk-Talnakh area, Siberia (Naldrett and Lightfoot, 1999). The aim of this paper is to provide an overview of Chinese Ni-Cu-(PGE) deposits and to classify them within the context of re Although platinum-group element (PGE) enrichment at the margins of large mafic-ultramafic intrusions has been known since the discovery of the Platreef in the Bushveld Complex by Hans Merensky in 1929, there remain fundamental questions about how this enrichment occurs. When a large hot sill is placed in the upper permeable crust, several phenomena occur. The country rock is commonly heated to, and then above, its solidus; partial melting occurs, and the siliceous volatile-rich melt "back-veins" into the fine-grained margins of the newly formed sill. Intrusion breccias may form with multiple pulses of magma into the country rock. Connate fluids in the country rock are initially driven away from the intrusion, but soon they convect and hydrothermally alter the contact zone (Barrie et al., 1999). In the contact environment, all of these processes may occlude the evidence for the primary magmatic processes responsible for initial metal enrichment (e.g., Naldrett, 1989). This contribution provides a preliminary assessment of the geology and Pd-Cu mineral deposits and occurrences in the Coldwell Complex, and addresses how both contact-type mineralization and magnetitite-associated reef-type mineralization occur in this setting. Generally, contact-type mineralization is characterized by: (1) a low sulphide content over tens of metres of thickness, (2) ubiquitous gabbroic (and/or ultramafic) pegmatite, and (3) the presence of magmatic breccias within and adjacent to the PGE-rich zones. Examples of contact-type PGE mineralization have been described recently for the Palaeoproterozoic East Bull Lake intrusion and suite in the Sudbury area (e.g., Peck et al., 2001). Reef-type mineralization occurs in stratiform layers in layered mafic-ultramafic intrusions, with the Merensky Reef of the Bushveld Complex, South Africa, as a classic example (Sharpe, 1986; Barnes and Maier, this volume; Cawthorne et al., this volume). The Coldwell Complex is a large (-530 km2) transitional tholeiitic to alkalic sill or lopolith that was emplaced during the early stages of rifting in the Mid-Continent Rift system, which includes the Keweenawan flood basalts, the Duluth Gabbroic Complex, and the Nipigon and Logan sills (Fig. 1). It contains the Marathon Pd-Cu deposit that occurs at the intrusion base and margin. The Marathon mineralization is associated with pegmatitic textures that indicate a role for exotic or deuter