To assess the performance of underground excavations and ground support when subjected to mining-induced seismicity, a site has been instrumented at the Kiirunavaara mine. Geophones, multi-point extensometers and instrumented bolts were installed at the site. After the installation, several large seismic events (local magnitude>1.5) have occurred near the site and caused serious damages. The results from site monitoring indicate that the seismic waves are amplified near the excavation surface. The rock mass and rock bolts respond to mining-induced seismicity with step changes in displacement. The ejection velocity back-calculated from the energy absorbed in the rock bolts shows good agreement with the measured peak particle velocity (PPV). It is concluded that the scaling law used to evaluate the ground motion near excavation surface needs to be improved by considering velocity amplification. Repeated loading from multiple seismic events should be considered to assess rockburst damage.
ISBN för värdpublikation: 978-0-367-42284-4; 978-0-367-82317;
Funder: LKAB (2014-01944, 2017-02228); Lundin Mining; Conselho Nacional de Desenvolvimento Científico e Tecnológico