The electrochemical rate constant shows that all the minerals have greater reactivity for the reduction of copper(II) than iron(III) ions

The rate constant varies by about an order of magnitude within the mineral group for both iron(III) and copper(II) reduction

The ratio of the rate of copper(II) reduction to iron(III) reduction is significantly greater for the minerals containing copper than for those without copper

The observed influence of mass transport on the cathodic currents close to the mixed potentials for the reduction of copper(II) on platinum, pyrite and enargite has been quantitatively explained in terms of the effect of mass transport on the surface concentration of copper(I)

There do not appear to be any semiconducting effects on the reduction of iron(III) or copper(II) on these minerals