Technology and application of water-preserving mining in Jurassic coalfield in Ordos Basin

Coal is the ballast of energy security in China. Under the premise of ensuring the safety of coal resources development,the protection of water resources to the greatest extent is a major scientific problem facing the high quality development of coal industry in the Yellow River Basin. Taking the Jurassic coalfield in Ordos Basin as the background,the structural types of overburden,the development law of water-conducting fracture zone,the distribution characteristics of the surface fractures,the stability of the mining water-proof layer and the water-control scheme under different hydrogeological and mining conditions were carried out. For the protection of shallow groundwater in thick bedrock,monitoring and analyzing the development characteristics and connectivity between water-conducting fracture zone and surface fracture,this paper put forward the water-maintaining mining technology to ensure the stability of water-isolating layer; aiming at the surface water body protection under the condition of shallow-buried thin bedrock and thick soil layer,the restraining effect of the clay water-isolating layer on water-conducting fracture zone and water-resistance effect under the influence of mining were discussed,and the water-retaining mining technology based on the water blocking effect of the mining clay was studied; for the deep multi-high-pressure aquifer,the water-retaining technology of "first dredging then mining and the combination of dredging while mining" was put forward,realizing the maximum protection of water resources under the premise of safe mining.