Development height measurement and water source analysis of water-conducting fractured zone in Hulusu Coal Mine

Predicting the development height of water-conducting fractured zones is crucial for roof water exploration and release design in order to eliminate water inrush or well flooding accidents in overlying aquifer. Through numerical simulation, drilling and water injection, observation, it is found that the development of water-conducting fractures in 21404 working face gradually evolved from an initial “arch shape” to a “saddle shape”. The height of water-conducting fractured zones show an upward trend, and the maximum value is achieved at a pushing distance of 90 m, which is 116.8 m. The actual water injection test results show that the maximum height of water-conducting fractured zones is 120.5 m, and the relative error with most methods is less than 5%. The hydrochemical and microbial characteristics indicate that the water quality type is typical of Zhiluo Formation water. It indicates that the direct water source of the goaf is Zhiluo Formation aquifer, which has the characteristics of retained and reduced water chemistry. The hydraulic connection between goaf and Cretaceous aquifer is weak.