Reuse and stabilization of sulphide mine tailings as fine aggregate for construction mortar

The processing of low-grade sulphide gold ores generates a significant volume of tailings which impacts the environment. The reuse of sulphide mine tailings as a substitute for sand in construction mortar offers the advantages of reducing costly tailings management whilst promoting sustainable construction. However, the acceptance of mine tailings as alternative sand for construction depends on its effective stabilization during use. In this study, hardened mortar cubes have been prepared by varying the substitution of river sand with sulphide mine tailings. The stabilization effects of cement, cement-lime and cement-pozzolana on sulphide mine tailings have been investigated. The water demand, slump behaviour, bulk density, water absorption, compressive strength, and X-ray diffraction (XRD) were examined to observe the physical and mechanical properties of the mortars. The water demand and bulk density decreased whilst the slump value and water absorption increased with increased tailings replacement. The highest 28-day compressive strength of 12.2 MPa was achieved at 25% tailing replacement with a cement binder. Cement proved to be the best binder for the stabilization of the tailings which was followed by cement-pozzolana and cement-lime respectively.