Main water-rock interactions and hydrochemical evolution in the aquifers under the mining-induced disturbance in a mining district

Coal mining is bound to destroy the natural hydrochemical environment. However, hydrochemical studies of a groundwater system of multi-aquifer in the mining district rarely focus on the essence of hydrochemical evolution under the mining-induced disturbance in view of space and time. The Linhuan coal-mining district is taken as an example to reveal the mechanism of water-rock interactions under the mining-induced disturbance by using the principal component analysis based on conventional ions over the years. The result shows that the first principal component represents the dissolution of carbonate and sulfate and oxidation of pyrite and the second principal component represents the exchange and adsorption of cation and desulphidation. Under the mining-induced disturbance, dissolution of carbonate and sulfate and oxidation of pyrite wear off in the main inrush-water aquifers in the mining district, but the change characteristics of exchange and adsorption of cation and desulphidation are insignificant. The research will provide a theoretical support for the identification of water-inrush source and also for the protection and utilization of groundwater in mining districts.