The Moroccan phosphate deposits are the largest in the world. Phosphatic layers are extracted in open-pit mines mainly in the sedimentary basins of Gantour and Ouled Abdoun in Central Morocco. The purpose of this study was to prospect and evaluate the water potential of aquifers incorporated in the phosphatic series using the following geophysical methods: Magnetic resonance sounding (MRS), electrical resistivity tomography (ERT), time-domain electromagnetics (TDEM), and frequency-domain electromagnetics (FDEM). The objective was, on the one hand, to contribute to the success of the drinking water supply program in rural areas around mining sites, and on the other hand, to delimit flooded layers in the phosphatic series to predict the necessary mining design for their extraction. The use of geophysical methods made it possible to stratigraphically locate the most important aquifers of the phosphatic series. Their hydraulic parameters can be evaluated using the MRS method while the mapping of their recharge areas is possible through FDEM surveys. The results obtained in two selected experimental zones in the mining sites of Youssoufia and Khouribga are discussed in this paper. The application of the implemented approach to large phosphate mines is in progress in partnership with the mining industry.

To improve the knowledge on available groundwater and to better characterize the aquifers on the phosphate deposits at Youssoufia and Khouribga (Morocco), several geophysical surveys using Magnetic Resonance soundings (MRS), Frequency Domain Electromagnetic Method (FDEM), Time Domain Electromagnetism (TDEM) and Electrical Tomography (ERT) were performed. The goal was to test the capability of these methods to localize an aquifer and estimate its hydrogeological properties. The first experimental results indicate the presence of highly conductive zones that could be related to the presence of water. MRS data has permitted to better constrain the aquifer parameters. The hydrogeological model provided by these methods is similar to the one obtained by piezometric data.