Method of gangue grouting filling in subsequent space of coal mining

The disposal and utilization of mine solid waste is a common problem in China’s coal mining，which seri⁃ ously restricts the coordinated development of coal resources and environment. Underground filling is one of the impor⁃ tant approaches for environmentally friendly and efficient disposal of solid waste in mines. However，the existing fill⁃ ing technology increases the production process of the working face and reduces the mining efficiency by 15%-20%. It is urgent to solve the problem of time⁃space interference between solid waste filling and coal mining， and break through the technical bottleneck of underground solid waste backfill in coal mines. In this paper，the present situation and existing problems of the disposal and utilization of gangue were summarized，the method of grouting filling in the space after mining with gangue was raised，the connotation and key problems of grouting filling after coal mining were systematically expounded，the spatial layout of grouting filling system was given. The research highlights of the steady⁃ state control mechanism of the fluidity of heterogeneous gangue slurry，the characteristics of void structure of the space after mining and space⁃time evolution law，the migration and diffusion law of slurry and the control mechanism of rock stratum with grouting filling were discussed. The research difficulties of millimeter grouting filling materials，the effi⁃ cient preparation and transportation of slurry，the layout and time control of grouting boreholes，and the intelligent mo⁃ nitoring of grouting filling were analyzed. The research results of this paper can innovate a new mode of efficient dis⁃ posal of gangue underground coal mine，and further improve the technical system of comprehensive disposal and utili⁃ zation of gangue，and lead the new direction of environmentally friendly，safe and efficient development of coal in Chi⁃ na，and there are broad application prospects in efficient disposal of solid waste in mines and ecological environment protection，which can promote the construction of environmentally friendly development mode of source emission reduc⁃ tion，on⁃site disposal and recycling of solid waste in mines.