Mechanism and technology of roof collaborative controlling in the process of Jurassic and Carboniferous coal mining in Datong mining area

The large space stope roof structure is complex, stope pressure appearing frequency is high, and the mine pressure is strength, that all affect the mine safety production. Based on the conditions of the Jurassic and Carboniferous coal mining in Datong mining area, the coal pillar impact was studied on the basis of the roof structure analysis, a roof structure model of the continuous arch was established, and the mechanism of roof collaborative controlling in the large space stope was revealed. The results show that the disturbance height was about 150 m in the process of the special thick coal seam mining; it formed a roof structure with the characteristic of low position composite beam + meso-position masonry beam + high position roof structure; and the structure unstability of the high position roof was the main controlling factor which inducing the stope strong pressure. The depth of stress concentration zone was about 100 m in floor strata under the Jurassic coal seam, and the continuous arch structure joint with the coal pillar transmitted load intensively, which was the strengthening condition that inducing the stope strong pressure. Thus, changing the roof structure of large space stope was the key to prevent and treat the stope strong pressure. The concept of roof collaborative controlling was proposed and the controlling technology of ground fracturing and confined blasting were curried out to obtain the better control effect. © 2018, Editorial Board of Journal of CUMT. All right reserved.