Using Grout Curtain to Cut-Off Regional Groundwater in Maoping Lead–Zinc Mine, SW China

This paper presents a case presentation of using large-scale grout curtain to cut-off regional groundwater in a nonferrous metal mine with extremely complex hydrogeological conditions, Southwest China. When deep mining under strong karst aquifers, grout curtain method is usually adopted to control and mitigate water inrush risk, reduce mine drainage volume and power resource consumption. A large area of surrounding rocks along the grout curtain axis are reinforced by using grouting as an impermeability treatment. In Maoping Lead–zinc Mine, the average drainage volume of the whole mining area is about 35,000 m3/d and increased year by year with the continuous increase in the mining depth and intensity, which would consume huge power resources and bring huge economic pressure to mining enterprises. In order to reduce the risk of water inrush and discharge volume, two grout curtains were design and installed to cut-off regional groundwater from north and south of the mining area. A red clay slurry modified by cement and sodium silicate was used to install this two grout curtains. Using combined drilling methods to reduce the drilling hole amount and save construction investment. The two grout curtains have a great significance to ensure the safety of deep mining for Maoping Lead–zinc Mine and which will serve the whole life cycle of mine. At present, the average drainage volume of the whole mining area is significantly reduced, the sealing efficiency of grout curtains is more than 50%, the final target is 65%. This paper will analyze the hydrogeological conditions and the grout curtains of Maoping Lead–zinc Mine in detail, as well as give a current construction progress and positive effects correlating to these two grout curtains.