Zhang Haitao, Jiang Binbin, Zhang Haiqin, Li Peng, Wu Min, Hao Jingwei, Hu Yutian
State Key Laboratory of Water Resource Protection and Utilization in Coal Mining, Beijing 102211, China.
School of Earth and Environment, Anhui University of Science and Technology, Huainan 232001, China.
ACS Omega. 2024 Jun 18;9(26):28726-28737. doi: 10.1021/acsomega.4c03073. eCollection 2024 Jul 2.
Constructing underground reservoirs in coal mines can effectively improve the recycling of mine water. Water-rock interactions within underground reservoirs have been demonstrated to improve water quality; however, the mechanisms underlying these water-rock interactions remain unclear, hindering the widespread applications of underground reservoirs. Thus, this study focused on the underground reservoir of the Shendong Daliuta coal mine. Through on-site sampling tests and single-mineral leaching experiments, combined with X-ray diffraction, X-ray fluorescence spectrometry, and scanning electron microscopy, the water quality characteristics of the inlet and outlet water samples from the coal mine underground reservoir were analyzed. Moreover, the physical and chemical properties of the collapsed rocks in the reservoir were investigated, with the aim of clarifying the mechanism underlying the water-rock interactions in coal mine underground reservoirs. The results revealed a significant self-purification effect of the coal mine underground reservoir. Compared with the inlet water sample, the outlet water sample featured substantially reduced amounts of solid-suspended substances, turbidity, total dissolved solids, and electrical conductivity, with the average removal rates of Fe and Mn approaching 98.73 and 92.12%, respectively. Along the flow direction of the inlet and outlet water of the coal mine underground reservoir, the concentrations of Na and Cl presented an increasing trend, whereas the concentrations of Ca, Mg, and HCO presented a decreasing trend. The concentration of K changed insignificantly, while the concentration of SO fluctuated unstably. The collapsed rocks in the Daliuta coal mine underground reservoir primarily comprised mudstone and sandstone with mineral components including quartz, orthoclase, albite, illite, kaolinite, glauconite, calcite, and pyrite. Among these, kaolinite exhibited the strongest adsorption capacity for Na, Ca, and Mg present in the mine water, while glauconite demonstrated the strongest dissolution capacity for Mg. Illite presented the strongest dissolution capacity for K, while albite presented the strongest dissolution capacity for Na. The water-rock interactions within the coal mine underground reservoir primarily included dissolution and adsorption processes, wherein mudstone and fine sandstone both played dominant roles in the adsorption of Ca, as well as in the dissolution of K, Na, and Mg. In particular, mudstone exhibited a stronger adsorption capacity than fine sandstone, whereas fine sandstone presented a stronger dissolution capacity than mudstone. Thus, our results offer theoretical guidance for understanding water quality purification mechanisms in coal mine underground reservoirs.
在煤矿中构建地下水库可有效提高矿井水的循环利用。地下水库内的水岩相互作用已被证明能改善水质；然而，这些水岩相互作用的潜在机制仍不明确，这阻碍了地下水库的广泛应用。因此，本研究聚焦于神东大柳塔煤矿的地下水库。通过现场采样测试和单矿物浸出实验，结合X射线衍射、X射线荧光光谱和扫描电子显微镜，分析了煤矿地下水库进出水水样的水质特征。此外，研究了水库中垮落岩石的物理和化学性质，旨在阐明煤矿地下水库水岩相互作用的潜在机制。结果表明，煤矿地下水库具有显著的自净化效果。与进水水样相比，出水水样中的固体悬浮物、浊度、总溶解固体和电导率大幅降低，铁和锰的平均去除率分别接近98.73%和92.12%。沿煤矿地下水库进出水的流动方向，钠和氯的浓度呈上升趋势，而钙、镁和碳酸氢根的浓度呈下降趋势。钾的浓度变化不显著，而硫酸根的浓度波动不稳定。大柳塔煤矿地下水库中的垮落岩石主要由泥岩和砂岩组成，矿物成分包括石英、正长石、钠长石、伊利石、高岭石、海绿石、方解石和黄铁矿。其中，高岭石对矿井水中的钠、钙和镁表现出最强吸附能力，而海绿石对镁表现出最强溶解能力。伊利石对钾表现出最强溶解能力，而钠长石对钠表现出最强溶解能力。煤矿地下水库内的水岩相互作用主要包括溶解和吸附过程，其中泥岩和细砂岩在钙的吸附以及钾、钠和镁的溶解中均起主导作用。特别是，泥岩的吸附能力比细砂岩更强，而细砂岩的溶解能力比泥岩更强。因此，我们的研究结果为理解煤矿地下水库水质净化机制提供了理论指导。
