Sustainable Mining and Metallurgy

In the mining of double-system extra-thick coal seams in Datong Coal Mine, the use of aggregate-containing slurry grouting filling technology to seal rock fractures can reduce the disturbance of mining to fractures and reduce the water conductivity of broken rock masses. It is a key measure to prevent goaf water and harmful gas leakage and prevent collapse of mining areas. Using mine solid waste fly ash as green filling material can realize the reuse of solid waste resources. Based on the Euler two-way coupling model, the CFD-DEM coupling model was constructed by using the coupling function of Fluent and Edem software. The migration and deposition behavior of aggregate particles in cracks with slurry and its influence on slurry flow velocity were analyzed. It is found that the aggregate particles with smaller particle size and lower density have a longer migration distance, and the particle size is a more important factor affecting the aggregate deposition rate compared with the density. During the migration process, the aggregate-solid ratio of each particle size and density shows a trend of increasing firstly and then decreasing. The sedimentation rate gradually increases with the increase of the migration distance, and at the same position, the aggregate with higher density shows a higher sedimentation rate. The research results provide a theoretical basis for the rational utilization of mine solid waste filling materials and the improvement of grouting plugging technology.