3-D Interpretation and Cement Fill Monitoring Using GPR over an Abandoned Gypsum Mine

P051 3-D INTERPRETATION AND CEMENT FILL MONITORING USING GPR OVER AN ABANDONED GYPSUM MINE Summary A Ground Penetrating Radar survey was carried out for cavity mapping and monitoring of the shallow subsurface conditions. The survey is located on a building site at the flank of the Mont- Valérien (larger western Paris suburb France) where an indoor tennis hall is under construction. Ancient gypsum mine galleries at 10-30 metres depth are a safety hazard in the shallow subsurface. Ground stabilisation is achieved by injecting cement in the cavities. Problem is to predict the outline of the cavities as grid drilling is