Over the past 25 years, underground mine flooding in the lorraine iron Basin (France) has resulted in a high concentration of dissolved sulphate and have made the water unsuitable for human consumption. this problematic issue has led to the development of numerical tools to support waterresource management in mining contexts. as water flows mainly in galleries and collapsed zones, we consider the flooded mine as a network of pipes and tanks. the software used for simulating flow andreactive transport in this network is the ePanet 2 code. a simplified sulphate dissolution-precipitation model, based on previous works, is included as source/sink in the tanks. Flow rates are calculated by processing data records with a rainfall-discharge model. the simulator gives good agreement between the calculated and observed sulphate concentrations.