Study On Gradually Crossing Coal Technology

It is greatly dangerous and often takes a long time for a tunnel to cross gas-logged coal inclined to coal and gas outburst at a coal mine, which is often a bottleneck for the mine's production plan and technology implementation. In view of imperfection of traditional crossing coal technology, this article has researched the gradually crossing coal technology developed at Songzao Coal Mine Bureau in Chongqing, Qijiang county after carefully analyzing mechanisms about coal and gas outburst presented from home and abroad and summarizing characteristics of coal and gas outburst when crossing coal.Considering that coal and gas outburst results from the combination of intrinsic properties of coal seam and some external incentive factors, physics and mechanics characteristics of coal have first been discussed, then relationship between coal's parameters and coal and gas outburst has been established. Furthermore, based on much experimental application, this technology doesn't emphasize so-called safety rock pillar as before, and it substitutes the traditional means of crossing coal seam through concussion blasting which is often responsible for many coal and gas outbursts with a moderate means crossing coal using smooth-surface blasting characterized by less excavation, less progress at a time; in addition, the safety in the process of crossing coal seam is guaranteed through establishment of safety screen by advanced bore hole which efficiently eliminates inducement of coal and gas outburst by external incentive factors.In this article, how these physics and mechanics parameters of coal seam interrelate to outburst and how to determine them have been elaborated, especially a method for quick surveying the gas pressure of coal seam has been developed; a new way based on experience at Songzao Coal Mine Bureau for more accurate prediction of coal and gas outburst has been presented; the rearrangement of holes for forecasting outburst in a three-dimension way further guarantees accuracy of forecast.The results attained in this article might benefit the current practice of crossing coal seam for a cross-cut in a theoretical and practical sense and also be a great contribution to crossing coal seam technology.