Abstract
Coal and gas burst is one of the significant and catastrophic hazards in underground longwall operations. To date, the protective coal seam mining has been recognized as the most effective mining method for minimizing or even avoiding the effect of the coal and gas burst. In this paper, numerical modelling and field test were carried out for the longwall operation in Qidong Coal Mine in order to investigate the induced stress and coal seam gas drainage performance in the protected coal seam after the complete extraction of the protective coal seam. It was found that four stress zones can be classified in the protected coal seam being the original stress zone, stress concentration zone, stress relief zone, and recompaction zone. In addition, the monitoring data of gas concentration and volume change in the field agree well with the numerical modelling results.
Highlights
China has one of the largest mining industries in the world and due to the increasing complex geological conditions and mining depth, the frequency of the coal and gas burst occurrence tends to increase. e number of incidents resulted by the coal and gas burst in China accounts for 40% globally
As the mining depth increases, the geological stress increases and so does the concentration of the coal seam gas. e existing mines that used to have low gas concentration are challenged by the increasing gas concentration as the mining operation moves deeper
The new mines face the challenge by high gas concentration from the beginning of the operation. e incidents caused by the coal and gas burst have been occurring from time to time [1,2,3]
Summary
China has one of the largest mining industries in the world and due to the increasing complex geological conditions and mining depth, the frequency of the coal and gas burst occurrence tends to increase. e number of incidents resulted by the coal and gas burst in China accounts for 40% globally. Chen et al [6,7,8] carried out research to investigate the permeability of the coal seam during mining operation and revealed that such a permeability would increase significantly due to the effect of stress relief and fractures in the seam resulted by mining activities. Wang et al [13] used the soft coal seam adjacent to the thick seam as the protective coal seam He et al [14] investigated the permeability change in the upper coal seam during the extraction of the lower protective coal seam and developed an analytical model to simulate such a change during mining operation. Xue et al [20] investigated the stress relief and permeability increase in the protective coal seam during mining operation and developed physical models that capture subsidence zone and fracture distribution zone in the protective coal seam. It was found that the numerical model results agree well with field monitoring data
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
