Simultaneous Impact of Open-Pit and Underground Mining on the Subsurface and Induced Seismicity

Resumo

In the fourth quarter of 2016, the system for monitoring induced seismicity in the Kuznetsk Basin (Kuzbass) began to record increasing seismic activity in the area of the Kaltan open-pit coal mine, which was struck by a series of seismic events felt in cities and settlements of the Kuzbass. In addition to the existing monitoring network, a temporary network of stations has been established, which has significantly increased the accuracy and representativeness of technogenic earthquake records. Markedly expressed seismic activation near open mine works (the Kaltan open-pit mine) has been revealed. The seismically activated area covers several open mine works and their vicinity. The strongest earthquakes have occurred outside the open-pit mine at the boundary of the dump. Inside the activated area, near the operating underground mine works (the Alarda mine), local seismic activation represented by low-energy technogenic earthquakes has been recorded. The largest number of perceptible earthquakes occurred in the fourth quarter of 2016. According to the monitoring data, the number of earthquakes with magnitudes 2.5–4 decreased in early 2017, but since February 2017, seismic activation has increased around the underground mine works, which was manifested as a significant increase in the number of low-energy technogenic earthquakes. In fact, the technogenic seismic hazard has shifted from open mine works towards the area of the operating underground mine.