Unexpected sericite-chalcocite mineral particles' hetero-aggregation occurs under aqueous processing conditions where both minerals display negative zeta potentials. In this study, the use of anionic copolymers (carboxylate-versus sulphonate-substituted) as dispersants to suppress the hetero-aggregation behaviour was investigated in the pH range 5-9. Both polymers showed strong substrate and pH-dependent adsorption and electrokinetic potential characteristics onto both minerals. The adsorption propensity was considerably higher onto chalcocite than sericite particles and dramatically accentuated at pH 5 for the former due to leached electropositive Cu(II) species' surface activation effect. At high polymer dosages (>1.5 g kg(-1) solid) leading to plateau adsorption density, the magnitude of both mineral particles' zeta potential increased to a maximum. Furthermore, the adsorbed polymer layer dominated the interfacial chemistry that showed Subtle mineral phase and pH dependency. The concomitant particle interactions reflected a marked reduction of dispersion shear yield stress and the suppression of sericite-chalcocite particulate adsorption. Electro-steric repulsive forces are believed to be responsible for the dispersing mechanism. Both polymers displayed similar, high dispersing efficacy at dosages >1.5 g kg(-1) solid for sericite-chalcocite mix dispersions, regardless of the pH. Crown Copyright (C) 2009 Published by Elsevier B.V. Ail rights reserved.