Abstract: The Ordovician and Taiyuan Group karst aquifers at the bottom of the coal measures in the North China-type coalfield have strong water abundance，high water pressure，and thin aquifuge. The confined water seriously threatens the safety production of coal mining enterprises. Based on the back⁃ ground of the mining face with pressure in a mine，it is analyzed that the water inrush coefficient of the floor of the 9303 working face is 0.094~0.126 MPa/m，and the mining will be threatened by confined wa⁃ ter damage. The ground directional drilling area grouting technology is used to carry out treatment for the target aquifer of 12~30 m below the top surface of Ordovician limestone. The results show that the thick⁃ ness of the aquifuge is increased by 45.22~64.60 m，and the water inrush coefficient is reduced to 0.073~ 0.085 MPa/m，which meets the requirements of the industry standard and realizes the safe mining above the confined water.

Key words: pressure water damage, mining under pressure, directional drilling, regional advanced grouting treatment