School of Ecology and Environment, Inner Mongolia University, Hohhot, 010021, Inner Mongolia, China.
Environ Geochem Health. 2020 Oct;42(10):3101-3118. doi: 10.1007/s10653-020-00544-z. Epub 2020 Mar 11.
The interactions between groundwater and its environment was investigated in prairie mining area in this study, through the groundwater system evolutions in mining area before and after the mining actions (from 1973 to 2016) of Yimin coal mine. The results showed that (1) the mining activities of the open-pit coal changed the original reduction environment into the oxidizing environment in the mining area. The pyrite and sulfur-bearing coal in the stratum oxidized, produced acid and triggered a series of subsequent reactions, resulting in the decrease in the pH value of the groundwater in the mining area. The concentration of SO, Fe, Fe, Ca and Mg and the total hardness increased. The regional hydrochemical type evolved from HCO-Na·Ca·Mg type before mining to the type of HCO·SO-Na·Ca·Mg after mining. (2) Coal mining strongly draining underground water accelerated the regional groundwater circulation, and then made the groundwater desalination. The concentrations of TDS, COD and Na+K in the mining area all showed a decreasing trend. (3) The coal mining activities made the calcite and dolomite in saturated state under the natural condition of underground water to be unsaturated again. The hydro-geochemical action evolves from double control (water-rock interaction and evaporation-concentration) to water-rock interaction control.
本研究以伊敏露天煤矿开采活动为研究对象，通过对矿区开采前后（1973 年至 2016 年）地下水系统的演化，探讨了地下水与其环境之间的相互作用。结果表明：（1）露天煤矿开采活动改变了矿区原有的还原环境为氧化环境，地层中的黄铁矿和含硫煤发生氧化，产生酸并引发一系列后续反应，导致矿区地下水中 pH 值降低，SO、Fe、Fe、Ca 和 Mg 浓度以及总硬度增加，区域水化学类型由开采前的 HCO-Na·Ca·Mg 型演变为开采后的 HCO·SO-Na·Ca·Mg 型。（2）采煤强烈疏干地下水，加速了区域地下水循环，进而使地下水淡化，矿区 TDS、COD 和 Na+K 的浓度均呈下降趋势。（3）采煤活动使地下水中碳酸钙和白云石在自然条件下由饱和变为不饱和，水地球化学作用由双控（水岩相互作用和蒸发浓缩）演变为水岩相互作用控制。
