Using stable isotopes (δD, δ18O, δ34S and 87Sr/86Sr) to identify sources of water in abandoned mines in the Fengfeng coal mining district, northern China

• Published in: Hydrogeology journal 2018-08, Vol.26 (5), p.1443-1453
• Main Authors: Qu, Shen, Wang, Guangcai, Shi, Zheming, Xu, Qingyu, Guo, Yuying, Ma, Luan, Sheng, Yizhi
• Format: Article
• Language: English
• Subjects: Abandoned mines; Aquatic Pollution; AQUIFERS; Calcium; CALCIUM IONS; Chemical composition; CHINA; Coal; COAL MINES; Coal mining; CONTAMINATION; Earth and Environmental Science; Earth Sciences; Environmental impact; Geochemistry; Geology; Geophysics/Geodesy; GEOSCIENCES; GROUND WATER; Groundwater; Hydraulic gradient; HYDRAULICS; Hydrogeology; Hydrology/Water Resources; Isotope composition; ISOTOPE RATIO; Isotopes; LIMESTONE; Mine drainage; Mine waters; Mining; Ordovician; Organic chemistry; OXYGEN 18; Ratios; RESOURCE MANAGEMENT; Resources; Stable isotopes; STRONTIUM 86; STRONTIUM 87; STRONTIUM IONS; Strontium isotopes; SULFUR 34; Sulfur isotopes; Sulphates; Underground mines; UNDERGROUND MINING; Waste Water Technology; Water analysis; Water Management; Water Pollution Control; Water Quality/Water Pollution; WATER RESOURCES; Water resources management; Water sampling
• ISSN: 1431-2174; 1435-0157
• DOI: 10.1007/s10040-018-1803-5

With depleted coal resources or deteriorating mining geological conditions, some coal mines have been abandoned in the Fengfeng mining district, China. Water that accumulates in an abandoned underground mine (goaf water) may be a hazard to neighboring mines and impact the groundwater environment. Groundwater samples at three abandoned mines (Yi, Er and Quantou mines) in the Fengfeng mining district and the underlying Ordovician limestone aquifer were collected to characterize their chemical and isotopic compositions and identify the sources of the mine water. The water was HCO 3 ·SO 4 -Ca·Mg type in Er mine and the auxiliary shaft of Yi mine, and HCO 3 ·SO 4 -Na type in the main shaft of Quantou mine. The isotopic compositions (δD and δ 18 O) of water in the three abandoned mines were close to that of Ordovician limestone groundwater. Faults in the abandoned mines were developmental, possibly facilitating inflows of groundwater from the underlying Ordovician limestone aquifers into the coal mines. Although the Sr 2+ concentrations differed considerably, the ratios of Sr 2+ /Ca 2+ and 87 Sr/ 86 Sr and the 34 S content of SO 4 2− were similar for all three mine waters and Ordovician limestone groundwater, indicating that a close hydraulic connection may exist. Geochemical and isotopic indicators suggest that (1) the mine waters may originate mainly from the Ordovician limestone groundwater inflows, and (2) the upward hydraulic gradient in the limestone aquifer may prevent its contamination by the overlying abandoned mine water. The results of this study could be useful for water resources management in this area and other similar mining areas.