Methods for water resource protection and water hazard prevention in sandstone aquifers of ancient river channels

HUA Zhaolai; FAN Limin; LI Zenglin; SUN Kui; WANG Lu; LÜ Yang; MA Wanchao; LI Qiang

Abstract：There are 24 mining areas in the Ordos Basin that exploit Jurassic coal seams,with raw coal production ac-counting for about 45%of the national total.With the increase of mining depth,the sandstone aquifer of the Zhiluo Formation in the coal seam roof has become the main source of water inrush in coal mines.The water content of the Zhiluo Formation sandstone aquifer is relatively weak,but the water release effect is significant under mining condi-tions,making it the main source of long-term and sustainable water supply for coal mines.At the same time,the area belongs to an ecologically fragile area with relatively scarce water resources.How to effectively utilize limited water re-sources is undoubtedly an important foundation for the protection of the groundwater system and ecological environment in the mining area.Taking the Yushen mining area and Caojiatan coal mine as examples,this paper proposes the tech-nical route,main research content,and research methods for studying the sandstone aquifer in ancient river channels.Using comprehensive sedimentology,hydrogeology,and mine water prevention and control theory to assist necessary field geological surveys,typical profile measurements,specialized investigations of hydrogeological and environmen-tal geological typical elements,drilling,geophysical logging and sampling testing,numerical simulation,and oth-er methods.We will focus on conducting research on three aspects:the sedimentary evolution and physical character-istics of ancient channel sandstone aquifers,the groundwater system characteristics of ancient channel sandstone aqui-fers,and the mutual feedback mechanism between ancient channel sandstone aquifers and coal seam mining.The re-search practice in Shenfu South District shows that the sand body of the ancient river channel in the lower section of the Zhiluo Formation has a huge scale and good pore and fracture structure characteristics,with good underground water storage and transportation performance.Overall,it is distributed in a NW-SE trending strip along the Hongjian-nao Erlintu Jinjie line as the axis.The fourth and fifth sections of the Yan'an Formation were eroded by the ancient river channel of the Zhiluo Formation.The main river channel area has a stronger water richness than the branch riv-er channel and diversion bay area,and is a high-risk area for mine water inrush.Therefore,water hazard prevention and control should be done well.