Experiment of backfill mining with aeolian sand high water swelling material in Yuyang Coal Mine

Taking 2307 fully-mechanized backfill working face in Yuyang Coal Mine as background, mining experiment was carried out by use of backfill technology with aeolian sand high water swelling material. Aeolian sand, fly ash, gypsum, quicklime and other common building materials were used as backfill materials, and ratio of the backfill materials was determined according to requirements of the backfill material and test as follows: aeolian sand was 366.3 kg/m3, fly ash was 366.3 kg/m3, auxiliary material was 81.6 kg/m3, water was 650.8 kg/m3. Backfill step was 6.4 m in condition of no initial fracture in immediate roof. Backfill capacity could reach 360 m3/h by adopting two sets of backfill slurry preparation devices and backfill pipes with backfill capacity of 180 m3/h. Backfill technical process was proposed. The experimental results show that there is no obvious pressure phenomenon in the working face, backfill strength basically meets the requirements, deformation of roadway surrounding rock is small, and surface subsidence is controlled effectively, which achieves goal of water-preserved mining as well as good economic benefit.