Impacts of Yuyang Coal Mine on Groundwater Quality in Hongshixia Water Source, Northwest China: A Physicochemical and Modeling Research

Abstract

The Yuyang Coal mine drainage can potentially have a negative impact on the surrounding drinking water, including the Hongshixia water source, causing detrimental effects to the environment and on human health. Here, contamination from the coal mine was analyzed by physicochemical interpretation and numerical simulation. We constructed two sampling profiles along the groundwater flow and transverse directions, and collected twenty-six groundwater samples near the drainage ponds from the Yuyang coal mine for physicochemical analysis and interpretation. And in terms of the numerical simulations, we chose the MODFLOW software to describe river, drainage ponds and reservoir and establish the flow model. We chose the MT3DMS modular software to build a solute transport model, and established a three-dimensional transient numerical model to predict the migration of total Fe and SO4 2−. The physicochemical analytical results indicate the groundwater quality degrades as we approach the drainage ponds. The variations of ion concentrations in the eastward and northward directions show the migration distance of the contaminants in the eastward direction (e.g., the direction of groundwater flow) is much greater to that in the northward direction (e.g., perpendicular to the groundwater flow direction). Numerical simulation results suggest within the predicted days, the concentrations of Fe and SO4 2− in the mine drainage ponds will be higher to that of the acceptable levels recommended by the national groundwater quality guidelines, imposing serious risks to the surrounding groundwater and human health. The pollution plumes of the contaminants migrate closer to the groundwater source governed by groundwater flow, suggesting the mine drainage may pose a risk to the groundwater quality of the Hongshixia water source.