Research progress on in-situ intelligent sorting and filling technology of coal gangue underground

Coal gangue needs to be transported to the ground for further treatment in traditional underground mines, which not only occupies land spaces, but also causes atmospheric and environmental pollutions due to spontaneous combustion and rainwater leaching. Moreover, energy consumption problems caused by long-distance ineffective transportation have become a key bottleneck restricting the low-carbon development of coal mines. In order to realize the underground disposal of coal gangue, and to reduce carbon emission and energy resource consumption per unit output from the source of coal production, as well as to realize the green low-carbon intelligent mining of coal, the present situation and intelligent progress of underground sorting and filling technology of coal gangue are comprehensively reviewed, and in this regard, the developing trend of underground sorting and filling technology of coal gangue is also anticipated. Meanwhile, an innovative method of underground in-situ green intelligent sorting and filling of coal gangue is proposed, and the structure and principle of coal gangue intelligent sorting and new filling hydraulic support are described in detail, so as to minimize the invalid transportation distance of gangue. In order to deal with the gangue of coal mining face and prevent the dynamic disaster of coal and rock, an intelligent integrated system of mining, sorting and filling in coal mine is designed, including four subsystems, i.e., an intelligent mining system with less gangue, an in-situ intelligent sorting system, a mine pressure inversion system of working face and a precise scientific filling system. Meanwhile, new logic relationships among multiple subsystems are discussed, so as to form a virtuous cycle of coal mining conducive to sorting, sorting conducive to filling and filling conducive to coal mining. In order to deal with the gangue in the heading face, an intelligent integrated system of underground excavation, aimed at sorting and filling in coal mine is proposed also with four subsystems, i.e., an intelligent fast excavation system, an intelligent sorting system, a coal gangue transportation system and an intelligent filling system, and the work and intelligent realization of each subsystem are described. The proposed new process in this study is expected to realize the underground disposal of coal gangue, and provide new ideas for the research of in-situ intelligent sorting and filling method of coal gangue and the integrated system of mining, sorting and filling.