Stress changes in underground mines – from investigation to practical tools

Purpose and goal

The aims are: 1) to develop methodologies for continuous monitoring of the stress changes in the mines using proxies (seismic tomography, stress inversion, grid analysis of seismic source parameters). Data from in-situ stress monitoring and high-quality numerical modelling will be used for verification and to show which methodology can be used and how. 2) to investigate the relationships between stress changes and seismicity in four different mines in Sweden using the new methodology. Results will be used for seismic hazard assessment and mine design purposes.

Expected results and effects

The results from the project will have direct practical application in all participating mines for sustainable mine production. The results will be used in a few different ways: 1) data (moment tensor, stress inversion results, numerical modelling results) have value by themselves; 2) practical recommendations/procedures (adjusted for each mine) can be used directly after the project is completed for stress monitoring using the proxies and for seismic hazard assessment, closing/re-opening of mine areas; 3) mine planning purposes based on identified stress changes.

Planned approach and implementation

The work is planned to be done by: Lulea University of Technology, Uppsala University, LKAB (Kiruna and Malmberget mines), Boliden (Garpenberg mine), and Zinkgruvan Mine by 15 people people (incl. a PhD and one postdoc) in 3 years. Stress- cells will be installed for stress monitoring in Kiruna and Malmberget mines. The methodological part will be completed in full extent in Kiruna and Malmberget mines and as much as possible for Garpenberg and ZInkgruvan mines. The relationships between stress changes and seismicity will be studied for all four participating mines.