Microseismic monitoring strategy as a key component of post-mining risk management: Review and feedback experience over the past decade

摘要

In France, abandoned anthropogenic underground excavations underlie tens of thousands of squared kilometres, disseminated through most regions in various geological settings, at depths ranging from a few meters down to hundreds of meters. A significant part of those ancient mines have been exploited by room and pillar techniques, with extended, multi-level, varied geometries and interlaced voids, creating uncountable specific situations. Most of the mines are ancient and were closed with no or very poor considerations about long term stability, at a time when knowledge in rock mechanics was not as advanced as nowadays. But time adversity is ineluctable with ageing man-made geostructures and key issues posed by abandoned room and pillar mines has focused an important societal attention with a series of large-scale ground collapses and subsidence phenomena that occurred in the old iron basin of Lorraine from 1996 to 1999, triggering emergency evacuations and reopening brutally socio-economic scars let by the mine industry decline after-effects. Numerous sinkholes were also reported during that same period of time unveiling eventually the whole mining industry inheritance and its potential toll for the next decades to come.