Influence of water yield property of Yan’an Formation aquifer on water yield of mines in southern Shenmu-Fugu mining area

Aiming at the large difference of water yield of different mine fields in Yushenfu mining area, based on a large amount of drilling, pumping test data collected in the area, from the weathering and denudation, burning effect, discontinuous distribution regions of aquifuges, microscopic pore structure, the influencing factors of water yield property of Yan’an Formation aquifer(YFA) are analyzed. Combined with the height of the water-conducting fissure zones, the influence of water yield property of YFA on water yield of mines is discussed. The results show that weathering and denudation cause the sandstone of Yan’an Formation to develop fissures and be broken seriously, enhance its permeability and connectivity. With the increase of weathering ratio, water yield property of YFA increases. The fissures and holes of sandstones in Yan’an Formation are significantly increased due to burning effect, and the water yield property is enhanced with the increase of the thickness of burnt rocks. Discontinuous distribution regions of aquifuges provide a hydraulic connection channel between the YFA and other aquifers. The water-conducting fissure zone formed by coal mining connects the weathered bedrock section and the burnt bedrock section of Yan’an Formation, resulting in a large amount of water yield of mines. The superposition of various factors in the region will lead to the enhancement of water yield property in the YFA, and the local area presents strong water yield property ~ extremely strong water yield property. After the water-conducting fissure zone is conducted, the water yield of mines will be large, threatening safety of coal mines. The influence of water yield property of Yan'an Formation on the large water yield of mines was further discussed. All these can provide the reference for safe mining and water hazard prevention of coal roofs in the Yushenfu Mining area.