<p>The present invention relates to a method of processing a sulphide mineral composition which at least partly comprises an iron containing mineral, the method comprising the steps of: (a) milling said composition to a particle size P80 of 20 microns or less; (b) leaching said composition with a solution comprising sulphuric acid and ferric ions at ambient pressure whilst sparging with an oxygen containing gas in an open tank reactor at a temperature of up to about the boiling point of the solution, whereby at least some of the acid and at least some of the ferric ions are obtained from dissolution of the iron containing mineral, and ferrous ions generated by the leaching reaction are substantially re-oxidised to ferric ions in the leaching solution; (c) precipitating excess iron and separating said iron together with any solid materials from the leaching solution; (d) extracting desired metal ions from the leaching solution by solvent extraction with an organic solvent, such that the raffinate comprises sulphuric acid and ferric ions; (e) returning the raffinate to the leaching tank and blending with further milled composition; (f) separating the metals from the organic phase obtained in step (c) by stripping with electrolyte and electrowinning.</p>
