Hydrogeological characteristics and prevention countermeasures of “fifth aquifer” in Zhuxianzhuang coal mine

The main water hazard during mining of seam 8 in northern mining district comes from the "fifth aquifer" of the roof Jurassic in Zhuxianzhuang coal mine. During extraction in the first mining face 866-1 under the fifth aquifer, water and sand burst accidents of the "fifth aquifer" have occurred, causing significant losses. The "fifth aquifer" has complex occurrence conditions and exploration degree is low, it was necessary to further explore and analyze its hydrogeological conditions and characteristics of water disasters, so as to put forward the countermeasures to eradicate the threat of water hazards. It was needed to research the hydrogeological and water damage characteristics further. From the space distribution, geologic structure development, law of karst development, hydrogeology and zoning, water chemical features, water level dynamic changes and the supply relationships with the main aquifers, the thorough research of "fifth aquifer" was carried out. It is concluded that the main water disaster features of "fifth aquifer" is big static reserve and good runoff condition, with high water pressure and strong dynamic supply, then, "curtain closure" and "dewaterring mining" were put forward as the combined countermeasures used to prevent water disasters.