Description: Publication date: Available online 30 June 2018 Source: Water Science Author(s): M. Gomo This article presents and discusses conceptual hydrogeochemical characteristics of dolomite and calcite acid mine drainage (AMD) neutralised circumneutral groundwater system. The conceptual discussions are based on the consideration of calcite and dolomite AMD buffering hydrogeochemical processes. Using theoretical chemical reaction stoichiometry, predictions are made for molar ratios of associated AMD – calcite and dolomite buffering reaction products (SO 4 2− , Ca 2+ and Mg 2+ ). Comparison is made between stoichiometrically predicted molar ratios of SO 4 2− /Ca 2+ , SO 4 2− /Mg 2+ , Ca 2+ /Mg 2+ and field data from previous studies in South Africa. There is a close match between stoichiometrically predicted molar ratios of the calcite and dolomite AMD neutralisation reaction products and field data. The results provide basis to improve the conceptual understanding of hydrogeochemical processes associated with dolomite and calcite AMD neutralisation which is important for field investigations related to mine-water quality, water management, remediation and overall environmental protection. Results further demonstrates the potential usefulness of relating ion concentration molar ratios of field measurements to stoichiometric predictions as a tool to identify hydrogeochemical processes controlling the evolution of groundwater chemistry.