Lateral curtain interception technology and water conservation effect in groundwater abundant mines of China

There are many types and numbers of mines in China, covering coal, metallurgy, non-ferrous metals, chemical industry and so on. Most of the mines use dewatering and drainage to control groundwater, and some of the water abundant mines have tens of thousands of m³ to hundreds of thousands of m³ of mine drainage per day, which causes the problems of declining groundwater level, water resources depletion, karst collapse and ground subsidence, surface water pollution, and deterioration of groundwater environment. In order to solve the problem of safe mining and water waste in water abundant mines, research on mine water cut-off curtain technology has been carried out since 1960 s, and after nearly 60 years of development, it has developed from single ground straight drilling and grouting to various water cut-off curtain technologies such as ground directional drilling and grouting, downhole drilling and grouting, combined drilling and grouting up and down the shaft, row of piles, continuous wall and seepage control membrane, etc. In more than 80 mines, semi-closed, closed, drop-bottom and suspended water interception curtains have been successfully applied, with water interception rate mostly above 60% and water level on the outside of the curtain significantly raised, achieving very good application results and protecting mine water resources and mine ecological environment. Four typical water interception curtain cases, such as metal mine karst fissure water fully closed curtain, coal mine bedrock drop bottom type slurry curtain, loose layer and karst stratum directional horizontal hole slurry curtain, loose layer impermeable membrane drop bottom type curtain, were selected for detailed elaboration, and the water interception technology and water resource protection effect of typical water interception curtain cases were analyzed, and the effective water interception rate was above 75%. Based on the development trend of curtain water interception technology, it is proposed that the technologies of continuous jointless water curtain in the lateral direction of loose layer, directional diffusion grouting in the lateral water curtain of bedrock, and lateral water curtain in the thick grass-roots level with low permeability are future directions, so as to practice the concept of “Green Mountains Are Mountains of Gold”, to protect the groundwater resources of mine, and to realize water conservation, ecology conservation, loss reduction and green mining.