France had a significant mining activity during the second half of the 20th century, until the closing of the last uranium mine Jouac in 2001. The aftercare of mines was entrusted to AREVA SA. It includes arrangements for limiting and controlling discharges and impacts from them. This master thesis focuses on the effluent of a former uranium deposit in Limousin (Bessines-sur-Gartempe). At a field campaign water samples were taken out of existing piezometers. These water samples were analyzed to obtain their chemical composition by AAS, Emanometry, IC and ICP. At last step a simulation with the hydrodynamic program HYTEC was done. With this model the spreading of chemical elements and minerals in the groundwater for further ten years is described. The results show elevated levels of sulfate and several heavy metals. Uranium and radium values are often above the limits for a direct discharge into the receiving watercourse. The simulation shows that oxidation of pyrite causes a decrease in pH which leads to a release of heavy metals.