A process for the extraction of a base metal such as Ni, Co or Zn, from suiphide ore or concentrate containing copper and the base metal comprises the step of subjecting the ore or concentrate to pressure oxidation in the presence of oxygen and an acidic solution containing halide and sulphate ions to produce a product solution containing copper and the base metal. The product solution is subjected to a copper extraction process for recovering copper from the solution and the product solution containing the base metal after copper recovery is recirculated for recycled to the pressure oxidation to effect build-up of the base metal in the product solution. Preferably, a stream which is split from the product solution is treated for the recovery of the base metal.