Microseismic monitoring strategy as a key component of post-mining risk management : review and feedback experience over the past decade
Résumé
The ceasing of a two centuries intense French underground mining industry has let a stupendous number of disused mines exploited by the room and pillar method. By the end of the 1990s, a series of catastrophic ground collapse and subsidence phenomena in urbanized zones occurred, triggering the foundation of a post mining national policy and launching a national scale prevention strategy. The high number of densely inhabited zones rated at risk along with the infrequency of such unpredictable events that may be delayed for decades oriented the decision makers to deploy the use of permanent monitoring as a key component of the prevention plan. Field experiments were undertaken for careful validation and optimal design in different geological and mine settings, including a controlled collapse experiment. A decade has passed since a first early warning microseismic system was set up. An overall review of this strategy, based on a global cost-benefit approach, is described and discussed by the authors.