Potential for bulk mining of oxidized platinum-group element deposits

Abstract

The market for platinum-group elements (PGE) is profitable, but difficult to enter for newcomers. The main difficulties are in extraction technology, economics and marketing. Novel metallurgical processing technology may offer a route for the development of currently sub-economic PGE deposits that are amenable to surface mining. The merits of various pyro- and hydrometallurgical process routes are discussed. Before more detailed process development work can proceed it is necessary to understand the mineralogical balance of the PGE in oxidized mineralization. An example is presented from the Main Sulphide Zone (MSZ) mineralization of the Great Dyke, Zimbabwe. The PGE in the sulphide zone occur dominantly in the form of discrete bismuthotelluride, arsenide and sulphide minerals, whereas in the oxidized zone they occur as oxide or hydroxide minerals and aggregates as well as relics of the primary minerals. Such mineralogical contrasts have important implications for potential open-pit mining and processing.