Experimental changes in flow parameters and solute transport in agglomerated copper tailings after leaching

Abstract

Many years of copper mining in Chile have left large quantities of waste material stored in tailings ponds. The extraction of copper with sulfuric acid using heaps of agglomerated tailings has been a subject of recent study in Chile. Although the agglomeration of tailings improves the natural hydraulic properties of the material, it has been observed that the acid changes the hydrodynamic properties of the agglomerated tailings. To quantify these effects, the hydraulic and solute transport properties of this material were measured before and after leaching. Flow, tracer and leaching experiments were performed in a column under unsaturated con-ditions. The breakthrough curves obtained were analyzed by the convection-dispersion equation using a dual porosity model. The results demonstrated the effects of the acid on the agglomerated. The parameters most af-fected were the dispersion coefficient, the fraction of adsorption sites in contact with the mobile water and the adsorption coefficient.