A method is proposed for assisting the commercial electrowinning of copper at current densities up to 600 A m(-2). The method utilises modifications to existing electrode feed manifolds to produce an air-electrolyte jet that mixes the cell contents and improves the copper mass transfer by shrinking the Cu2+ concentration boundary layer around the cathode. A series of design criteria for the modified manifolds are proposed and utilised to select an appropriate orifice diameter (d(i) = 2 mm). Experimental flow modelling studies showed that acceptable mixing performance was possible for current densities in the range 400-600 A m(-2), with appropriate air and electrolyte pressure operating parameters also provided. Pilot-scale electrowinning trials indicated that for no air sparging, industrially unacceptable copper cathode was produced at current densities of 600 A m(-2). However, the proposed air-electrolyte system could produce high quality cathode at these conditions with little apparent evidence of unwanted dendrites or nodules.