ABSTRACT
Destress rock blasting is focused in the regions of expected high stress concentration. Destress blasting is used as a rockburst control technique mostly in the deep ore mines (e.g., Comeau et al., 1999, Mitri et al., 2000, Saharan & Mitri 2009) despite the fact that the idea comes from the coal mining industry (Springhill Colliery, Canada in 1930s;
1 INTRODUCTION
Rockbursts in the Upper Silesian Coal Basin (USCB, see Fig. 1) have represented a very dangerous phenomenon for a long period of time (e.g., Straube 1972, Petuchov & Zamarski 1990, Takla & Ptacek 1991, Holecko et al., 1999, Konecny 2005, Dubinski & Konopko 2000, Drewiecki & Kabiesz 2008, Drzewiecki et al., 2011). The rockburst problem relates primarily to the existence of competent rocks in the rock mass and to the irregular stress fields induced by long-term excavation. The occurrence of a critical stress field leads to brittle failure of not only the coal, but also adjacent rocks. Such rockbursts are then, as a rule, a result of long-term
McInnes et al., 1959). The presented system of destress rock blasting to provoke rockburst, is a unique European system used in the Czech part of the USCB, in areas of high stress in the rock mass (Dvorsky & Konicek 2005, Konicek et al., 2011b). Rockburst can be provoked by destress blasting in favourable conditions and two examples of provoked rockburst from the USCB are presented here.
