Modeling the Effects of Phosphate Mining on Groundwater at Different Stages of Mine Development

Abstract

In this study, a three-dimensional hydrogeological conceptual model was developed and a numerical model was calibrated with Visual MODFLOW to predict groundwater flow and evolution of groundwater field at different developmental stages at a large phosphate mine in Leibo, China, the Baku mine. ArcGIS was used to quantify changes in groundwater flow direction. The development of the cone of depression in the surrounding mining areas was predicted and the associated environmental impacts were discussed. At the beginning of mining, the cone of depression is limited to near each mining subarea and the drawdown is relatively small. The cone spreads out to the Liutong River as excavation proceeds. The model also estimated groundwater inflow rates into the different mining tunnels. The greatest inflow rate occurred in mining subarea M1.2 due to its large scale of mining and low elevation of the bottom of the tunnel. The results of this study can be used to plan optimal groundwater pumping and mine dewatering for safe mining at different mine development stages.