Application of short-wall continuous mining and continuous backfilling cemented-fill mining technology

The development and utilization of coal resources have caused serious surface collapse and destruction and ecological, environmental pollution. As the main method of green mining, backfill mining fills gangue and other wastes into the goaf to control the surface subsidence and processing coal gangue, which has broad application prospects. Aiming at the practical needs and significance of reducing gangue emission and controlling surface subsidence caused by high-intensity mining in fragile environmental areas in western China, this work proposed a short-wall continuous mining and continuous backfilling (CMCB) cemented-fill mining technology. On the basis of studying the mining principle of the short-wall CMCB cemented-fill mining technology, this work introduced layouts of this technology’s working face and mining and filling crafts according to the longwall working face and the short-wall working face, respectively, realizing the parallel operation of mining and backfilling by skip mining. The mineral composition, microscopic characteristics, and gradation characteristics of various filling materials were analyzed, and the strength and flow characteristics of the cemented filling materials under different proportions were tested on the basis of a filling material test combined with pipeline transportation characteristics and filling methods of the coal mine cemented-fill slurry. The composition and overall design ideas of the filling system of this technology were put forward, including four parts: slurry preparation system, pipeline transportation system, monitoring system, and working face filling system. The on-site test showed that the short-wall CMCB cemented-filling mining technology achieves a compression ratio of more than 98% in a 5-m thick near-level coal seam. The maximum roof subsidence is 102 mm, and the maximum surface subsidence is 8.9 mm. 245000 t of gangue were used, and a good application effect was observed.