ABSTRACT
The importance of using the destress blasting as an active rockburst mitigation measure has increased within the frame of present increase and development in mining depth and high horizontal stresses. The main goals of the destress blasting are softening of competent rock layers, reduction of strain energy storage and rock mass stress release, which together contribute to minimizing rockburst occurrence and risk. Case study of the destress blasting from Czech hardcoal mining in unfavorable geomechanical conditions is presented and evaluated in terms of rockburst prevention. Destress blasting stages were carried out in a group of boreholes (3–7) with the total explosive charge ranging from 1275 kg to 3075 kg, detonated regularly at a distance of 28 m to 52 m ahead of the advancing longwall face. Evaluation of destress blasting based on seismic monitoring revealed that the longwall blastings were very successful in terms of rock mass stress release and decrease the rockburst risk.
