Hydrological conceptual model characterisation of an abandoned mine site in semiarid climate. The Sierra de Cartagena-La Unión (SE Spain) Robles-Arenas, Virginia María Candela, Lucila Fractured aquifer Open-pit and underground mining Sierra de Cartagena-La Unión Acid mine drainage Semi-arid zone hydrology A comprehensive study at Sierra de Cartagena-La Unión (SE Spain) abandoned mine site was carried out to characterise the regime and water quality of the groundwater system after the mine closure. The system consists of five geologic fractured blocks belonging to the Alpujarride and Nevado-Filabride complexes. The aquifer units are composed of limestone and dolostone materials. Recharge is mainly controlled by the N-130 fault system, man-made induced fractures, open-pits and underground workings. Discharge is indicated from open pit lakes by the proximal dome-shaped groundwater level contours. Aquifer natural recharge, assessed by fracture density maps and chloride mass balance, provided consistent results. The water hydrochemical facies show a marked sulphate concentration and acidic pH (average pH of 2.53-6.30). A maximum concentration of 4,100 mg/L of Zn and 40,000 mg/L of sulphate was observed in open-pit lakes. Springs present the lowest residence time and are low mineralised with an average pH of 7.6. Geochemical modelling based on the PHREEQCI code indicates water undersaturation with respect to almost all related mineral species and anoxic conditions prevail in the system. Although an adequate understanding of the regional system is provided, a further detailed hydrochemical study is necessary to assess the undergoing geochemical changes. 2014-10-22T11:05:20Z 2014-10-22T11:05:20Z 2010 info:eu-repo/semantics/article Robles-Arenas, V.M.; Candela, L. Hydrological conceptual model characterisation of an abandoned mine site in semiarid climate. The Sierra de Cartagena-La Unión (SE Spain). Geologica Acta, 8(3): 235-248 (2010). [http://hdl.handle.net/10481/33462] 1695-6133 http://hdl.handle.net/10481/33462 10.1344/105.000001532 eng http://creativecommons.org/licenses/by-nc-nd/3.0/ info:eu-repo/semantics/openAccess Creative Commons Attribution-NonCommercial-NoDerivs 3.0 License Universidad de Barcelona