Abstract: When the mine is closed, the changes of groundwater hydrodynamic conditions may cause groundwater pollution and greatly
threaten the environment. The abandoned mine in eastern Xuzhou was chosen in this study, and groundwater samples were collected for
chemical analysis on the basis of hydrogeological survey. The results showed that the hydrochemical types in Taiyuan Formation
Aquifer exhibited obvious zonation, the types of which changed gradually from HCO3·SO4-Ca and SO4-Ca·Mg in north-west to HCO3·
SO4-Ca·Mg and HCO3-Ca·Mg in south-east. With the mine being closed, the groundwater level rose and the hydrogeological
conditions changed, leading to the variations of groundwater chemical components. According to the analysis of the evolution of
groundwater hydrochemical characteristics, groundwater in the study area was affected by cation exchange and adsorption, and the
concentrations of calcium ions, magnesium ions and sulfate ions increased, while those of sodium ions and potassium ions decreased.

Key words: abandoned mine, groundwater environment, hydrochemical characteristics