Shanxi Fenxi Ruitai Jingxing Mining Group Zhenghang Mining Industry Corporation around the coal mine cross-border phenomenon was serious before integration, with broad goaf, inaccurate borders, east and south of Sanpan Area threatened by old mine area water. Through supplement hydrogeological exploration, old mine area water area was estimated by 682 743 m2, water volume was 1 073 181 m3. Based on this problem, through analysis of the ground, underground transient electromagnetic exploration achievements, and combined with borehole drilling, exploring the empty area boundary, discharging goaf water, which ensured Sanpan Area construction safe.