As coal resources are mined at greater depths, ground stress, temperature, and water pressure increase. The changes in these conditions alter the effective stress distribution in deep rock formations. Primary fissures in the aquiclude are damaged, propagate, and progressively coalesce. Water flow channels are then formed, which may induce water inrush accidents from the coal seam floor. The mechanism of primary fissure extension leading to water inrush in the aquiclude of the 15252N working face in the Jiulong Mine, Fengfeng Mining Area, was investigated through theoretical analysis, numerical simulation, and physical similarity modeling. Key technologies for preventing and controlling water hazards in the working face were identified. The results show that mining at the 15252N working face causes the mining-induced failure zone to expand in both width and depth due to stress redistribution induced by excavation. Primary fissures in the aquiclude extend along the weakest structural direction. Confined water further promotes wedge-splitting and softening along fissures. This enhances the interaction between primary fissures and local shear-through fissure zones, and reduces the effective thickness of the aquiclude. Under the combined effects of mining-induced stress and confined water pressure, confined water migrates upward along fault-controlled seepage pathways, resulting in the further expansion of the confined water-conducting zone. When this zone connects with the primary fissures and the mining-induced failure zone, Ordovician limestone water enters the working face through the connected channels, causing floor water inrush.The research results provide theoretical support and technical guidance for the prevention and control of water hazards in deep coal mines with similar hydrogeological conditions.