Seismic activity reduction with the use of blasting and passive seismic tomography control, a case study from copper ore mine, Poland

Deep copper ore mines in Poland have been struggling with seismic hazard since almost fifty years ago when the first rock burst occurred. Increasing exploitation depth and mined-out space make the mining conditions constrained and severe causing the seismic activity to grow substantially. Consequently, rock burst preventive activities have to be incorporated into mining technology to provide work safety. To date, the group winning blasting has posed the most commonly used preventive measure, so its efficiency in seismic energy reduction is of significant importance for the rock burst hazard mitigation. The more energy blasting works provoke to release the safer the work environment gets. The article aimed to assess the efficiency of such an energy reduction, which was approached in two ways. Firstly, the drop of energy and in turn its reduction efficiency was assessed simply using a percentage of provoked tremors’ energy and number. Next, the analysis employed passive seismic tomography results to find if provoked tremors took place in high-velocity zones. The analysis made it possible to verify the assumption that the more provoked energy occurs in such zones the more successful preventive blasting is.