Abstract
Abstract : This paper presents the results of laboratory investigations conducted on gold mine tailings (GMT) to assess their chemical, mineralogical, leaching and geotechnical characteristics as well their acid generating potential in view of assessing its suitability as an alternative backfilling solution in mine reclamation. Chemical characterisation revealed that GMT is dominated by Si, Al and Fe with notable amounts of Cr, Zr, Zn, Pb, Ce, As, Ba, Ni, V, Sr, Nd, Cu, U and Co. Mineralogical characterisation revealed a composition of silicate minerals with secondary minerals such as jarosite, goethite and hematite. Acid base accounting (ABA) results showed that GMT are acid generating. During column leach experiments, leaching of elements and SO42- was significant at initial stages and became negligible thereafter. GMT composites exhibited moderate strength parameters. The effect of curing age and addition of cement contributed to the shear strength of the material. Furthermore, GMT showed favourable characteristics for use in mine backfilling; however, solid/liquid ratios should be maintained to ensure maximum strength. The use of GMT for backfilling is therefore possible; however, blending with higher percentages of cement and alkaline materials such as coal fly ash should be considered to chemically stabilise the material.