Paper Title
HYDRO GEOCHEMICAL CONTROLS OF SALINITY IN CIRCUMNEUTRAL COALMINE GROUNDWATER

Abstract
Abstract - Circumneutral groundwater prevents the leaching of toxic trace metals but poses huge salinity problems on the groundwater quality. The salinity problem in circumneutral groundwater has rarely attention as compared to the effects of metal leaching in the absence of buffering capacity. The study uses bivariate scatterplots and correlations analysis to elucidate the hydrogeochemical controls of salinity in the circumneutral coalmine groundwater. 770 field data sets from groundwater systems reported to be under circumneutral conditions in coalmines in South Africa are probed. The study identified the major hydrogeochemical processes contributing to salinity in typical circumneutral coalmine groundwater. Results show that salinity in such a circumneutral system is strongly and positively associated with sulphate, calcium, magnesium, bicarbonate, sodium and potassium released during the AMD-buffering hydrogeochemical process. Calcium and magnesium evolve from the buffering of AMD by calcite and dolomite while sodium and potassium emanate from AMD buffering by albite and K-feldspar respectively. Sulphate is the major contributor to salinity from these different buffering processes. Furthermore, the salinity evolution is not pH dependent on the circumneutral groundwater but rather the governing buffering equations. Keywords - Acid Mine Drainage; Buffering, Circumneutral; Groundwater Quality; Hydrogeochemical process, Salinity