Generic source term determination for tailings storage facilities in the East Rand Basin

Abstract

The prolonged leaching of gold tailings is a continuous concern in the East Rand Basin typically resulting in acid generation and the release of elements. The leachable constituents from the tailings influences the water quality of both surface and subsurface water negatively, resulting in degradation of the water sources through Acid Mine Drainage (AMD). A combination of samples was subjected to XRD, XRF, static tests, leach tests and geochemical modelling; with the aim to develop a generic sulphate source term of tailing impoundments in the East Rand Basin. A leachable sulphate production was determined for the East Rand Basin tailing dams. Geochemical and moisture profiles were used to produce a generic source term equation through PYROX, based on a generic function of sulphide and developed standardised moisture content within the tailings storage facilities. It was found that the modelling results over estimates the integrated sulphate production rate due to several unknown input parameters. Overall the generic source term equation was in close proximity to the PYROX simulated results, predicting a sulphate load based on the fraction sulphide present as the main variable input. The generic source term can be considered as an approximate estimation of loads expected within the East Rand Basin. The equation makes for a time conserving approach when compared to the PYROX software.