Height Detection Of Water-conducting Fracture Zone And Safety Zoning Of Fracture Caving In Huangling Mining Area

Detection of water-conducting fractured zone and safety zoning of fracturing are the basis of mine water control research.It is of great significance to accurately detect the development height of water-conducting fractured zone in coal seam after mining and correctly predict the safety of fracturing in coal mine area.In this paper,Huangling mining area is taken as the research area to carry out the research of water conduction fracture zone detection and fracture safety zoning prediction.Huangling mining area is an important coal production and transportation area in China.The topographic elevation difference is fluctuating and complex.The main coal-bearing stratum is the Jurassic Yan’an Formation.Coal Seam No.2 is the only coal seam with industrial value in the area,and is also the main coal seam currently mined.There are two main aquifers in the overburden bedrock of coal seam,namely,the sandstone aquifer in the lower part of Jurassic Zhiluo Formation and the confined aquifer in the lower part of Cretaceous Luohe Formation.The aquifer in the lower part of the Jurassic Zhiluo Formation is the main factor affecting its exploitation,and its water-rich is weak to medium.The development height of water conducting fractured zones with different mining thickness is detected by the method of subsection water injection drilling in downhole elevation hole.Taking 603 working face of Huangling No.1 Coal Mine as the detection object,the development height of water conduction fracture zone is calculated based on the leakage of borehole water.The detection results show that the height of caving zone is 42.2 m,the height of water-conducting fracture zone is 66.5 m and the ratio of crack to mining is 25.2.The detection results show that the height of caving zone is 62 m and the ratio of crack to mining is 16.5 for the 206 and 405 working faces of Huangling No.2 Coal Mine.The height of water-conducting fractured zone is predicted by using the developed height of water-conducting fractured zone obtained by drilling and the fracture-mining ratio in Huangling No.1 and Huangling No.2 coal mines respectively.The difference between the thickness of water-conducting fractured zone between No.2 coal seam and Zhiluo formation sandstone aquifer and the height of water-conducting fractured zone is taken as the index to predict the safety of fracturing,and the safety of fracturing in Huangling No.1 and No.2 coal mines is plotted.Full partition map.The results show that the unsafe area of cracking in Huangling No.1 Coal Mine is mainly located in the south-central part of the minefield and at the southwest boundary of the minefield.About 8.5 km2 is located in unsafe areas and even extremely unsafe areas;Huangling No.2 Coal Mine is more and more safe from south to north,and the area around the southern border is located in unsafe areas and unsafe areas.