Prediction of water inflow and evaluation of curtain water-blocking effect in the Panlong lead-zinc mining area

PENG Sanxi; LI Guifu; SHAN Huimei; LIU Yunquan; LU Danmei

doi:10.11932/karst20250507

Abstract：The importance of metal mineral resources as a vital component of China's social and economic development is self-evident.With the acceleration of industrialization,the demand for mineral resources has increased sharply,and mining activities have extended progressively deeper underground.However,the resulting water-inflow disasters are becoming increasingly frequent,seriously threatening both the safety of mine operations and balance of the ecological environment.Therefore,it is of great significance to scientifically and reasonably calculate and predict changes in water inflow and groundwater levels in mining areas,and to develop effective water prevention and control strategies to ensure safe production in these areas. Since the exploitation of the Panlong lead-zinc mine in Guangxi began,mine production has been affected by the erosion of surface water and groundwater.The Panlong lead-zinc mine is adjacent to the Datengxia Water Conservancy Project.When the Datengxia Water Conservancy Project commenced impoundment,the water level of the Qianjiang River rose significantly,enhancing the resistance to recharge of the Qianjiang River and greatly increased the risk of water inflow in the mining area.Focusing on the Panlong lead-zinc mine in Guangxi as the research subject,this study addresses the water inflow problems encountered during deep mining operations.By integrating with the hydrogeological conditions,karst development characteristics,and the current mining status,a three-dimensional numerical model of groundwater flow in the mining area was developed by GMS software.This model predicts water inflow and changes in underground flow field at different mining depths and evaluates the water-blocking effectiveness of grouting curtain project.The main research contents and conclusions are as follows: (1)Prior to the construction of the Datengxia Water Conservancy Project,the water level of the Qianjiang River reached 42 m,with the average total daily water inflow of the mine being 20,610 m3·d-1 and 21,263 m3·d-1,respectively,when mining extended to the middle of-3 80 m and-440 m. (2)Following reservoir impoundment with the water level of the Qianjiang River at 61.5 m,the total water inflow at the-440 m level increased to 26,639 m3·d-1,representing an increase of 5,376 m3·d-1 relative to pre-impoundment conditions.Meanwhile,a significant drawdown funnel developed,with recharge from the Qianjiang River on the eastern side and lateral groundwater inflow on the western side becoming the dominant water sources.This suggests that the elevated water level of the Qianjiang River,caused by the Datengxia Water Conservancy Project,may pose potential risks to the safety of mining operations. (3)Prior to the implementation of the eastern curtain,mining at the-440 m level under reservoir impoundment conditions resulted in a total water inflow rise of increase of 5,376 m3·d-1.Following the implementation of the eastern curtain grouting project,with reservoir impoundment(the water level of the Qianjiang River:61.5 m)and mining at the-440 m level,the total average daily water inflow was 23,548 m3·d-1,representing a reduction of approximately 3,091 m3·d-1 compared to pre-curtain conditions(26,639 m3·d-1).The results show that the eastern curtain project blocked only 3,091 m3·d-1 of water inflow,failing to completely eliminate the inflow problem. (4)Following the east-west curtain grouting project,under conditions of reservoir impoundment and mining at the-440 m level,the total average daily water inflow was 19,744 m3·d-1-an approximate reduction of 6,895 m3·d-1 compared to pre-curtain conditions.This effectively eliminates the increased water inflow caused by the impoundment-induced water-level rise,indicating the effective water prevention and control achieved by the east-west curtain project in the mining area. (5)Numerical simulation predicts that the total water inflow of the mine will reach 23,285 m3·d-1 when mining attains-740 m level,with the rate of water inflow increase slows down as the mining depth increases.In addition,flow field simulations indicate that,as mining depth increases,the range of the drawdown funnel gradually expands,hydraulic gradients intensify,and groundwater recharge pathways shift toward the bed of the Qianjiang River. This study can provide a scientific basis for the prevention and control of water inflow during the deep mining of the Panlong lead-zinc mine,while also offer theoretical support and practical guidance for safe mining and prevention and control of groundwater disasters in karst mining areas characterized by complex hydrogeological conditions.