Targeting drainage technology of roof sandstone water in super-long working face of Muduchaideng coal mine

The deep Jurassic coalfield mines in Ordos basin are generally faced with some problems such as uneven water-rich distribution of roof,large amount of water falling in stope after mining,large amount of drainage works,and so on. The advantages and disadvantages of short-distance rotary drilling group hole drainage technology and long-distance directional drainage technology were analyzed. According to the mine sedimentary geological characteristics,based on the comprehensive geophysical exploration results and the drainage results of the mining face,it was considered that the aquifer of Zhiluo formation of 3-1 coal roof was the key aquifer for dewatering design. A water richness evaluation model including sandstone thickness,sedimentary environment impact index and core adoption rate was constructed by using AHP analytic hierarchy process,and the water richness of the drainage target face was evaluated. On this basis,the water targeting drainage technology of roof sandstone with the combination of long-distan