Microseismic monitoring and rock mechanical back-analysis of the flooded Praid salt mine

The Praid salt mine disaster started by the Corund stream flood, which has penetrated into the mined areas. The National Salt Company SNS SA (SALROM) is in need for detection and localization of micro tremors generated by salt deformation; which is an early warning system for mine collapse. Beside the microseismic (MS) monitoring it is working a complex automatic total station (ATS) which by it is continuously monitored the ground surface displacements above the mined area and the village buildings at risk. Nevertheless, it is possible to record underground events using the monitoring system. In combination with geotechnical and surveying monitoring, a complex image of the processes taking place underground can thus be derived. In this article it is visualized also the hypocenters of the microseismic events in 3D view by using LeapFrog software together with the main geological features. The examination is followed by a previously developed method that originally used acoustic emission (AE) monitoring data when we started to use the solution, in combination with a primary BEM and FEM stress analysis, to visualize the possible stress nodes or concentrations and to back-calculate rock mass strength. In this study microseismic monitoring data will be used from Praid salt mine. AE and MS monitoring able to detect the pre-peak, peak, and post-peak stress changes in different rock masses beside the localization of the sudden stress redistributions..