Abstract: The process of open cut mining has an impact on the groundwater flow system，while few study reports the quantitative impact at present.In this study，a groundwater flow model in the Visual Modflow is built based on the hydrogeological conditions of an open-cut iron mining site in Sichuan.Then，the calibrated flow model was used to predict the distribution of groundwater flow，groundwater inflow rate and cone of groundwater drawdown at different mining elevations.The results showed that the groundwater flowed to the open pit locally.With the progress of mining lasting，the area of the groundwater drawdown increased from 0.54 km2 to 1.55 km2 and the groundwater inflow rate was 3 220~4 565 m3/d.The variation of groundwater inflow rate with seasons is revealed.The quantitative analysis by model predictions could provide a scientific support on the design of mining drainage and water control.

Key words: Open-cut mining, Groundwater inflow, Numerical simulation, Visual Modflow