Katowice Coal Holding (KHW) is one of the biggest coal companies in Europe. The company owns five coal mines with a daily output of around 60 000 tonnes of coal. In the Katowice city area, very good quality steam coal is extracted. The depth of mining varies from 400 to 1100 metres and some of our mines rank among the most afflicted with rockbursts in the Upper Silesian Coal Basin. The rockburst hazard has a very big impact on production and safety. Annually, several thousand seismic events occur there, of which the strongest ones reach very high energy level (Magnitude over 4). The destressing blasts carried out in both coal seams and roof rocks are designed to transform the rock mass structure and to release the accumulated seismic energy by safe and controllable means. As a result of blasting, the rock mass should be destressed. To assess the effectiveness of destressing blasting, informative geophysical parameters have been introduced. The distribution of these parameters allows rational control of preventive measures. This possibility has been confirmed by examples from longwalls and headings of KHW coal mines. The analysis and experiments allow some general rules to be stated for carrying out destressing blasts effectively. The effectiveness of blasting in the roof rocks and coal seam is very similar. The seismic energy released depends on the roof control system. For both, caving and hydraulic back filling systems, the performance of cyclic blasting in consistency with mining progress and working face advance is essential.
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