The storage of coal gangue, a solid waste byproduct, occupies valuable land resources and contributes to environmental pollution, making it a major concern. To enhance the utilization of coal gangue and promote its reduction at the source, resource recovery, and harmless disposal, this study investigates the preparation of cemented backfill materials using coal gangue from Bulianta Coal Mine as the binding agent. This approach aims to reduce the cost of cemented backfill. Three crushing methods were tested: two-stage crushing of coal gangue larger than 80mm, single-stage crushing of full-size coal gangue, and two-stage crushing of full-size coal gangue. The study involved crushing, screening, optimizing backfill proportions, and analyzing mechanical properties. Techniques such as X-ray diffraction (XRD) and X-ray fluorescence (XRF) were employed to support the research, yielding key performance indicators such as particle size distribution, uniaxial compressive strength, and bleeding rate. The results indicate that coal gangue particles were relatively coarse after single-stage crushing of full-size material, while the crushing method above 80mm yielded superior results. The particle size distribution post-crushing, with +4.75mm particles comprising 13.6%, was reasonable, and the resulting backfill slurry exhibited good workability. Among the three particle size combinations from the different crushing methods, the compressive strength of the backfill was significantly influenced. The highest compressive strength was achieved with two-stage crushing of coal gangue above 80mm, reaching 1.8 MPa at 7 days and nearly 4 MPa at 28 days. As the concentration increased, the coal gangue content rose, showing a positive correlation with strength. Coarse-grained coal gangue improved the bleeding properties of the backfill slurry, and as concentration increased and coal gangue content decreased, the bleeding rate gradually reduced.
gangue; crushing; particle; grading; uniaxial compressive strength
Luo W., Yang Z., Research on Cemented Paste Backfill Materials Based on the Crushing Effectiveness of Coal Gangue from Bulianta Coal Mine. Int. J. Geo-Energy, 2024, 2(4), doi: 10.58531/ijge1031000006
