Drilling Holes Spacing Optimization for Breaking Roof Blasting Pressure Releasing in Deep Hole of Jixian Coal Mine

In order to guarantee the safe mining of left 1^# working face of west 2^# mining area, the deep hole blasting technology has been used for rock burst prevention. The blasting hole spacing was preliminarily determined by 4.8 m through theoretical calculation, three groups of 3 m, 5 m and 7 m drilling holes spacing were chosen for industrial test, and blasting effect was analyzed by use of drilling hole imaging technology. The results show that fracture length, development density and porosity has a tendency to decrease with the increase of drilling hole spacing. In order to guarantee the blasting effect, and considering the quantities and costs, eventually, the reasonable drilling hole spacing of 5 m is determined, it provides a certain guidance and reference for the next phase of deep hole blasting in rock burst prevention.