Application of surface directional drilling technology in reforming the confined aquifer with high pressure in coal seam floor

The limestone water of Taiyuan Formation in the coal floor of No.6 coal seam in Hengyuan coal mine of Wanbei Coal and Electricity Group is a great security threat, especially in the fold and tectonic development area. However, the conventional control period is long and the effect is poor, the water threat cannot completely be eliminated. To solve the water disaster, the surface multi-branch drilling and grouting along coal seam and precise guiding technology were applied in mining district II63. The application results show that the surface directional drilling and grouting technology along the floor can realize the directional drilling along coal seam. Based on the strategy of "the synchronous exploration and grouting, the combination of exploration and treatment", the disorder of drilling, grouting, tunneling and mining is completely solved. The underground water inflow was less than 5 m³/h, and the working face II632 was mined in security and coal production was 1.68 million tons. There is no limestone water during the entire mining process, and the expected goal of water disaster prevention has been achieved. The successful application of the above technology guarantees the safe and efficient mining in the high risk working face with the extremely complex geological structure, and also provides a new water-disaster control method for the similar working face in the same kind of coal mine.