| Huangtun pyrite is located in the northeastern margin of Luzong volcanic basin.The main ore body occurs in the sedimentary rocks near the contact zone between volcanic rocks and basement sedimentary rocks below the surface of 100 ～ 300 m,which is a large concealed pyrite deposit.The mining area is covered by the Quaternary loose layer with the thickness of 20 ～ 50 m,and the pore confined aquifer is developed in the lower part of the Quaternary.In the surrounding rock near the orebody,the volcanic rock fissure-hole aquifer group with strong water-rich property constitutes the direct water-filled aquifer group of the mine;affected by faults and water-conducting fracture zones,the volcanic fissure-hole water-bearing rock group has good recharge conditions and high water pressure.In other words,Huangtun pyrite is a large-water mine located below the local erosion datum,mainly filled with bedrock fissure water,with complex hydrogeological conditions and large water inflow.The mine adopts the comprehensive water prevention and control scheme of the ground curtain grouting project,supplemented by the drainage of the mine inside the curtain;whether the curtain grouting project can effectively block the main supply channel of mine water inrush is the key to the success of the comprehensive water prevention scheme.The degree of curtain grouting engineering to block water inflow depends on the effectiveness evaluation of curtain engineering water plugging.In order to verify the overall water plugging effectiveness of curtain grouting project,after the implementation of the project,a long-term(continuous 7 months),large drawdown(maximum drawdown 120 m in the hole),large flow(2.4 ～ 3.0 million m3/d)group hole pumping test was carried out in the curtain.Under the influence of pumping,the groundwater in the direct water filling stratum in the curtain changes from pressure bearing to pressureless;under the influence of dewatering and drainage of the future mining conditions of the deposit,the groundwater in the direct water-filled strata inside the curtain will also be in an unpressurized state.The barrier of curtain engineering to the mine water inflow channel and the change of groundwater hydraulic properties in the direct water filling stratum will have a significant influence on the mine water inflow,which is also the evaluation result of the effectiveness of water plugging.Taking the curtain grouting project of Huangtun pyrite mine as the research object,the grouting project is tested and evaluated to meet the requirement of anti-seepage design q ≤ 3Lu.On the premise that the grouting curtain is qualified without affecting the effectiveness of curtain water plugging,according to the geological and hydrogeological conditions of the mining area,combined with the development and utilization scheme of the mine,the completed curtain project is regarded as a built-in water-resisting boundary in the groundwater flow system,and the hydrogeological conceptual model of the mining area is established.With the help of MODFLOW module in GMS software,the heterogeneous,anisotropic and quasi-three-dimensional numerical simulation model of groundwater flow with built-in impervious boundary is established.The numerical simulation model of groundwater flow is identified and verified based on the dynamic monitoring data of regional groundwater and the dynamic monitoring data of water level and flow during the long-term,deep drawdown and large flow group-hole pumping test.The numerical simulation model after identification and verification is used to predict the mine water inflow before and after curtain engineering.According to the change of mine water inflow before and after the curtain project,the reduction ratio of the curtain project to the mine water inflow,that is,the engineering water plugging rate,is evaluated to reflect the overall effectiveness of the curtain project.The research shows that for the three mining levels of-240 m,-290 m and-340 m designed for the development and utilization of the deposit,the water plugging rates provided by the curtain engineering for each mining level are 75.46 %,76.98 % and81.40 %,respectively,without considering the influence of the early mine inflow on the disturbance of groundwater flow field.Considering that the later replacement level(first mining-240 m,followed by horizontal replacement by depth)is affected by the early mine water inrush disturbance,the water plugging rates provided by curtain engineering for-240 m,-290 m and-340 m levels are 75.46 %,85.98 % and 89.08 %,respectively.The above water plugging rate evaluation shows that the curtain project effectively intercepts the lateral runoff of the main water-filled water-bearing rock group of mine water inrush.The main contents and results of this paper:Huangtun pyrite mine is a large,concealed and inflow mine with complex hydrogeological conditions.Taking the mine water prevention and control grouting curtain project as an example,the effectiveness of water plugging in grouting curtain project is evaluated.The main research contents and results are summarized as follows:(1)Main factors affecting the effectiveness of water plugging in curtain engineering,including the quality of curtain grouting project and the overall water plugging efficiency of the project;under the premise that the grouting quality is qualified and the construction meets the design requirements,the overall water plugging efficiency of the project is also related to whether the design meets the hydrogeological conditions.(2)The design value of the anti-seepage performance index of the ground grouting curtain project in Huangtun pyrite mine is q ≤ 3Lu.Through the corresponding in-situ test and detection of the grouting curtain project,the anti-seepage performance of the grouting project meets the design requirements and the quality is qualified,which does not affect the overall water plugging effectiveness of the curtain project.(3)According to the geological and hydrogeological conditions of the mining area,combined with the development and utilization scheme of the mine,the numerical simulation model of heterogeneous,anisotropic and quasi-three-dimensional groundwater flow with the built-in curtain engineering waterproof boundary is established.With the help of MODFLOW module in GMS software,based on the data of regional groundwater dynamic monitoring and large pumping test,the numerical simulation model of groundwater flow is identified and verified to predict the mine water inflow before and after the curtain project.(4)The overall effectiveness of curtain engineering is evaluated based on the prediction of mine water inflow before and after curtain engineering.The water plugging rate provided by the curtain project for each mining level is 75.46 % ～89.08 %,that is,the curtain project is more effective in the lateral runoff of the main water-filled water-bearing rock group of the mine water inrush. 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