In the Lorraine area of eastern France, decades of iron-ore mining from 1850 to 1997 have left vast underground cavities beneath or in the vicinity of urban areas. Several major collapses occurred in the southern part of this iron-ore basin in the 1990s, after the mine closure and the flooding of underground mine workings. Following these large-scale collapses, the French government initiated a strategy of post-mining risk management to prevent and control risks associated with these ground failures. The high-risk zones are secured either by reducing the vulnerability while the moderate risk zones are monitored for public safety purposes by using in situ monitoring. This monitoring relies mainly on real-time microseismic systems, to detect precursors to a rapid large-scale collapse. After the progressive closing and then flooding of the northern iron basin ending in 2008, subsidence was observed in a town of the Lorrain basin in

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The excavation of a deep underground structure induces a stress field redistribution that creates an Excavation Damaged Zone (EDZ). Study of EDZ physical properties is of prime importance in the framework of nuclear waste geological storage, where EDZ constitutes a preferential pathway for storage materials towards the biosphere. Use of ultrasonic wave propagation inside the rock media is of great help as a near field non-intrusive technique for this. The significant research activity in the laboratory offers a large number of boreholes. These boreholes form linear excavations with a perfectly round section. It is for this reason that a specific probe and inversion method have been developed in order to reconstruct the image of the velocity field all around the environment of the boreholes. In order to recover all data needed with high accuracy and minimum effort, the probe is fully monitored for automatic data acquisition.This numerical inversion method has been preliminarily applied to a multi layer test bed in order to validate and optimise the experimental and numerical procedures. Based on those results, an in situ experiment has been performed in the Meuse/Haute-Marne Underground Research Laboratory (URL) in France for the safety assessment of nuclear waste storage in the Callovo-Oxfordian argillaceous layer.