Abstract: The Gaojiabu Mine in the Binchang mining area is located in the middle of the Huanglong Jurassic coalfield. The main coal seam is overlaid by the Luhe Formation sandstone aquifer, which is characterized by great thickness, low permeability and uneven water abundance. As the mining depth increases, water hazards in the mine seriously threaten safe production. The existing drainage system is unable to meet the demand and needs to be expanded. Therefore, a centralized drainage system was constructed, and large-diameter drainage boreholes were implemented, with a borehole diameter of Φ950mm and a depth of 810m. A novel method was adopted to fabricate the casing cement buoyancy plug using "casing inner diameter reducer + welded threaded steel ring + prefabricated steel hook", and 378.8t of drainage pipelines were installed. During the construction of large-diameter drainage boreholes in this area, complex geological conditions were encountered, and accidents such as hole wall collapse and stuck pipe due to reduced diameter were prone to occur. The construction passed through the thick Luhe Formation sandstone aquifer, and the rock drillability was poor in some sections, resulting in low drilling efficiency and high overall project difficulty. To address these issues, this paper proposed targeted solutions such as controlling drilling fluid loss, optimizing drill string combinations, and maintaining drilling fluid performance, which achieved good practical application results and provided a feasible solution for water hazard prevention and control in the mining area.