An analysis of groundwater circulation in the Pingyu mining area based on hydrochemical and isotopic characteristics of groundwater

Abstract

Groundwater in mining areas play an important supporting role in the surrounding residents' living and the construction of coal industries. Mine drainage during coal mining will change the original groundwater circulation process in mining areas, leading to changes in the groundwater environment. Therefore, clarifying the mutual transformation relationship between the “three waters” is the key to the scientific utilization of water resources in mining areas. Chemical components and hydrogen and oxygen isotopes of the groundwater in the Pingyu mining area are combined to determine the characteristics of groundwater circulation after large-scale drainage of the mine, identify the origin and controlling factors of the major components in the groundwater. Hydrohemical analyses show that most of the groundwater are of HCO3—Ca·Mg type, The hydrochemical components are controlled by the weathering and dissolution of silicate, and the ions in the groundwater mainly come from water-rock interactions and the waste generated by human activities, with concentration of \begin{document}${\rm{NO}}_3^- $\end{document} exceeding the standard. The hydrogen and oxygen isotopic data demonstrates that the groundwater in the study area receives recharge from modern precipitation, and there is a close hydraulic relationship between the groundwater in the unconsolidated aquifers and the groundwater in the karst aquifer. After the mine drainage, the groundwater circulation process in the mining area changes, the karst groundwater changes from supporting the upper pore groundwater to accepting the leakage recharge of the upper pore groundwater, and then discharges to the surface water by the mine drainage. The mine drainage becomes the main groundwater drainage way in the mine area. The research results can provide scientific and effective basis for groundwater development management and land subsidence prevention in mining areas.

Keywords

• mine drainage
• hydrochemical characteristics
• hydrogen and oxygen isotopes
• groundwater circulation
• settlement area of pingyu mining area