1.Coal Mining and Designing Branch, China Coal Research Institute, Beijing ,China; 2.Coal Mining and Designing Department, Tiandi Science and Technology Co., Ltd., Beijing ,China； 3.Huafeng Mine,Xinwen Coal Mining Group Cororation Ltd.,Tai’an ,China

Pressure release blasting of unreasonable parameters often damages surrounding rock supports, which reduce the anti-impact capability of supporting rocks. This paper presents a method to optimize parameters of blasting coal seams. The method was based on theory of pressure release and support coupling. A mathematical model was established to derive the optimum intensity of unloading pressure. The factors that influenced the optimum unloading pressure were then analyzed. The study indicated that the optimum intensity of unloading pressure had no correlation with the initial state before unloading and supporting. However, the weighted influence that the pressure release and supporting had on the risk of outburst, the correlation coefficient between pressure release and supporting and risk of outburst, and the conversion coefficient between pressure release and supporting had effects on the optimum intensity of unloading pressure. The optimization method was established a blasting plan for Gushan Coal Mine to achieve the goal of best effect of pressure release and least damage of supporting rock. The results showed that the optimum hole length was 12 m and the optimum mass of explosive per hole was 6 kg. The field practice implementing these optimum blasting parameters indicates that this optimized blasting plan has an excellent pressure release effect and reduces the damage of supporting, while a high work efficiency is maintained.