Theory and technology of green filling of solid waste in underground mine at coal power base of Yellow River Basin

Nine of the 14 large⁃scale coal bases in China are located in the Yellow River Basin. For a long time，the sustained high⁃intensity development and utilization of coal resources have caused surface subsidence and solid waste accumulation，which has seriously affected the high⁃quality development of the ecological environment in the Yellow River Basin. Back⁃fill coal mining is an important way to free the coal resources with the “three under one up” condi⁃ tions，extend the service life of the mine，and solve the ecological environment problem caused by gangue pollution in the mining area，which can effectively reduce the impact and damage of coal mining on the natural，social and eco⁃ logical environment. In view of the demand of coal and ecological environment protection in the ecologically fragile area of the Yellow River Basin，the development status of coal mine back⁃fill mining technology was comprehensively in⁃ vestigated and analyzed，and the development process and mining characteristics of coal mine back⁃filling at the coal power base of the Yellow River Basin were obtained. Based on this，in order to take advantage of energy support of coal base and underground space left by coal mining，a new mode of solid waste and underground green back⁃fill mining in the Yellow River Basin is proposed. Combined with the development characteristics of Ningdong coal mine，coal power and coal chemical industry cluster， it urgently needs to carry out research in five aspects， i. e.， underground coal gangue source reduction and intelligent separation，solid waste heavy metal complexing passivation， functional porous adsorption material，preparation of green filling materials，and the multi⁃field theory of underground solid waste back⁃fill mining. In addition，it urgently needs to develop four key technologies，namely，long⁃distance safe and efficient storage and transportation of filling materials，collaborative roof control between filling body and surround⁃ ing rock，monitoring and control of filling mining effect，and collaborative utilization of coal based solid waste in the whole industry. In this way，the technology and theory can be established for the green mining of coal resources and the clean utilization of solid waste in whole value chain. It also provides a technical support for achieving the solid waste reduction，resourcelization，large⁃scale green utilization and ecological environment protection in the Yellow Riv⁃ er coal basin.