One of the most seismically active and also rockburst/rockfall prone areas in the mine is the production area called Block 33/34 (Fig. More than 1000 seismic events per day have been recorded in the whole mine during recent years. The mine has been seismically active since 2007 and the seismic activity increased as mining advanced deeper. Kiirunavaara mine (LKAB) is an underground sublevel caving iron ore mine located in Norrbotten county, Lapland Province, Sweden, and known as one of the largest and most modern underground mines in the world (Fig. As a result the importance of a reliable estimation of the seismic source parameters and understanding of the nature of the seismic events increases. ![]() Mine seismicity poses a hazard to the mine personnel and infrastructure and therefore it has become a major operational issue and a challenging planning factor for most underground mines worldwide, especially at depths greater than 900–1000 m. The energy and the apparent stress were found to be three times larger for FS events than for NS events.Īs the underground mining advances to greater depths, the stresses in the rock mass increase, and as a consequence the level of induced seismicity usually increases. The relationships between some source parameters and seismic moment/moment magnitude showed dependence on the type of the source mechanism. The rest 31 FS events were concentrated mostly around the production levels and slightly below them. Out of 46 events 15 events were classified as NS located almost in the whole range between 8 m, including many events below the production. The events were classified as shear/fault slip (FS) or non-shear (NS) based on the E s/ E p ratio (>10 or <10). 90% of the events were located in the footwall, close to the ore contact. The radiated energy for the studied events varied from 4.7 × 10 −1 to 3.8 × 10 7 J, the source radii from 4 to 110 m, the apparent stress from 6.2 × 10 2 to 1.1 × 10 6 Pa, energy ratio ( E s/ E p) from 1.2 to 126, and apparent volume from 1.8 × 10 3 to 1.1 × 10 7 m 3. The source parameters of the events were re-estimated using spectral analysis with a standard Brune model (slope −2). Hypocenter locations were refined using from 6 to 130 sensors at distances of up to 1400 m. The events occurred between 20 at mining level 850–1350 m in the Kiirunavaara Mine (Sweden). Forty-six mining-induced seismic events with moment magnitude between −1.2 and 2.1 that possibly caused damage were studied.
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