A process for the recovery of copper and cobalt from the Kakanda tailings dump was developed and evaluated during an integrated pilot plant campaign at Mintek. The process involved a number of unit operations including leaching, copper solvent extraction, copper electrowinning, iron removal, manganese solvent extraction, cobalt solvent extraction, ion exchange for impurity removal, and cobalt electrowinning. This paper describes the laboratory test programme required to enable the design of an ion exchange circuit for the removal of traces of copper and zinc from the cobalt advance electrolyte, as well as the pilot plant campaign to evaluate the final design.^L^LA resin was chosen for the removal of copper, and occasionally copper and zinc, from the cobalt advance electrolyte. During the pilot plant campaign a lead-lag fixed-bed system was evaluated at a superficial linear velocity of 0.5 cm/s (to be employed on the full-scale plant). The concentration of copper in the ion exchange feed varied between 60 and 100 mg/l and that of zinc between less than 2 and 10 mg/l. Effluent concentrations for both metals of less than 2 mg/l, specified for electrowinning, were consistently delivered for both metals. ^L^LThe full- scale design was based on an ion-exchange feed flowrate of 200 m3/h, and the final dimensions of the two columns were: inside diameter 3.7 m, and height 7.5 m. Variations of copper and zinc concentrations in the ion exchange feed solution were accommodated by changes in the operating strategy of the plant during piloting.