Approche spatialisée dans la modélisation hydrogéologique d'un ancien secteur minier: Spatialized approach in the hydrogeological modeling of an abandoned mining sector

Spatialized approach in the hydrogeological modeling of an abandoned mining sector The present study deals with the specific hydrogeology of an old iron mining sector in north-eastern France. We modelled flows in three dimensions, particularly disturbed by the presence of old mine galleries. Four layers, representing the aquifer system and impermeable formations, were digitalized; the network of galleries was implemented in the iron-bearing formation by using an option of the code MARTHE, which takes into account the geometry of the network of galleries. After a history matching based on two criteria - the hydraulic head at a point of the network of galleries and the overflowed volumes over about six years at another point - a simulation over six years correctly forecasts the changes in hydraulic head evolution at one point. Furthermore, sensitivity analyses demonstrate that the model is rather robust. Even though the amount of available data is low, our study shows that a three dimensional modelling is not impossible to achieve. Key words: Finite differences, galleries, iron mine, karst, Lorraine, 3D modelling