Qualification of the microseismic monitoring technique applied to the risk of collapse in iron ore mines

Abstract : Experiments carried out in a working iron mine validated the microseismic monitoring technique as a means of detecting fracture noise emissions regarded as signals indicating an incipient collapse. In the experiment surface recordings were made of the microseismic signals corresponding to fractures and local collapse phenomena generated at the mine bottom by deliberately destroying pillars. The pillar removal operations and the collapse of the roof were systematically correlated with a series of microseismic events. The experiment served to validate the microseismic monitoring technique as a means of detecting surface precursors of a collapse, to demonstrate the effectiveness of the technique, and to calibrate the principal parameters of a microseismic monitoring System adapted to detection and monitoring in areas where there is a risk of collapse.