Abstract:Huibaoling iron deposit is a large concealed sedimentary metamorphic rock type iron deposit, with large water inflow, high drainage cost and a threat to mine safety production. Before water control, the normal water inflow of the mine is about 530m3/h, including 163.5m3/h of the water inflow of the discovered poorly closed boreholes, which accounts for an important part of the mine water inflow. In this paper, characteristics of water inflow, water pressure and water filling source of the poorly closed borehole have been analyzed, and three underground grouting technologies, namely, grouting at the bottom of the borehole, staged pressure relief grouting and grouting with water cutoff wall have been put forward for the first time in the deep concealed iron deposit, and the underground grouting water stop system of the poorly closed borehole in the concealed iron deposit has been established. It has achieved good water stopping effect, which has important guiding significance for water stopping of poorly closed boreholes in similar mines.