Roadway Backfill Coal Mining to Preserve Surface Water in Western China

In China's western eco-environmental area, water resources are very valuable. Longwall mining can cause these shallow water resources to leak, so most mines in this area use room-and pillar mining to prevent water inrush and protect water resources. However, over time, coal pillars can become unstable and collapse. To protect water resources and improve coal recovery, roadway backfill coal mining was proposed for the Ershike Coal Mine. The mechanical properties of backfill materials with different ratios of aeolian sand, fly ash, and Portland cement were studied in the laboratory to obtain an optimal ratio. Also, a 2-D physical simulation model was established to explore the development of mining-induced fractures and to conduct a stability analysis of aquiclude strata. The results can be used to guide coal mining in the study area and to protect local water resources.