Structural influence on plume migration from a tailings dam in the West Rand, Republic of South Africa

Abstract

AbstractGold mining activity in South Africa is a potential cause of groundwater contamination. In particular, leachate infiltrating from tailings dams can affect surface water, as well as groundwater quality. This study was aimed at assisting an individual mine to investigate the groundwater flow system downstream of a tailings dam in order to predict contaminant plume migration emanating from the decommissioned dam. During the investigation, evidence was found that the contaminant plume emanating from the dam was affecting the groundwater quality in the area, predominantly by impacting on chloride and sulphate concentrations. It was suspected that structural features influenced plume migration rather than lithology, hence a strong emphasis was placed on the structural geology. The orientation of tensional and compressional couples were derived through tectonic analysis and verified through field observations. Incorporation of tensional structural features, acting as preferential groundwater flow paths, into a numerical model enabled the simulatation of the groundwater flow regime in the area to predict plume migration.