M.Sc. (Chemistry) / Cobalt is mainly associated with copper, both in the primary ores and in the oxidation zone. In Southern Africa cobalt metal is produced as a by-product of the extraction of copper, nickel and platinum group metals. The hydrometallurgical route is commonly used, since cobalt bearing materials are acid leached prior to the clarification and impurity removal process preceding the electrowinning of the value. In order to understand the dissolution behaviour of cobalt and copper bearing minerals from Co-Cu oxide ores, the relationship between and the impact of physical, chemical and mineralogical properties of the materials and the dissolution behaviour of cobalt and copper bearing minerals contained in the feed materials was studied. Four Co-Cu oxide ore samples namely; high cobalt ore (HCo), high copper ore (HCu), low cobalt ore 1 (LCo1) and low cobalt ore 2 (LCo2) were characterised in terms of elemental composition, cobalt and copper species, functional groups, mineral phases, mineral abundances, mineral/ore grains size distribution, particle specific surface area, particle ore density and porosity, in order to elucidate the impact of these properties on the dissolution rate and percentage recovery of cobalt and copper in the acid generated leachate...