A method of controlling the acid balance in a high chloride heap leach process tomaximise the copper dissolution in a cure step and to increase overall copper recovery which include an agglomeration stage in which acid and process solutions are combined with the ore prior to stacking to form a heap followed by a cure phase to leach a portion of the copper in the ore in the heap followed by an irrigated leach phase in which the remaining copper minerals are leached and copper is recovered from a pregnant leach solution by a solvent extraction step followed by an electrowinning step wherein the acid concentration in the pregnant leach solution which reports to the solvent extraction step is less than 10 g/L to allow effective copper recovery from the pregnant leach solution in the solvent extraction step.