Huang Pinghua, Li Yuanmeng, Yu Zhiheng, Peng Wanyu
School of Resources and Environment Engineering, Henan Polytechnic University, Jiaozuo, 454000, China.
Collaborative Innovation Center of Coalbed Methane and Shale Gas for Central Plains Economic Region, Jiaozuo, 454000, China.
Sci Rep. 2025 Jul 2;15(1):23647. doi: 10.1038/s41598-025-08832-3.
With the trend of deep coal resource extraction becoming normalized, understanding the mechanisms driving sulfate migration and evolution under the coupled effects of high geothermal environments and coal mining is crucial. This study investigates the sources and migration processes of groundwater sulfate under high ground temperature conditions using Self-Organizing Maps, stable isotopes (δS, δO, δD, δO), and Bayesian isotope mixing model (MixSIAR). The results indicate that, influenced by coal mining, the hydraulic connectivity between the aquifers above and below the coal seam is significant. High ground temperature conditions accelerate sulfide oxidation and evaporite dissolution, leading to sulfate concentrations in limestone water that are several times higher than those in normal geothermal coal mines. Additionally, coal mining accelerates groundwater circulation, intensifying mixing processes. The combined application of isotopes (δO and δS) and the MixSIAR model reveals that the majority of sulfate in the coal seam's underlying limestone water originates from evaporite dissolution (39.60%), while the sandstone water is significantly affected by mixing processes, with evaporite dissolution (38.70%) and sulfide oxidation (31.08%) playing equally important roles. These findings provide theoretical support for the utilization and management of groundwater resources in deep coal mines.
随着深部煤炭资源开采趋势常态化，了解高地热环境与煤炭开采耦合作用下驱动硫酸盐迁移演化的机制至关重要。本研究利用自组织映射、稳定同位素（δS、δO、δD、δO）和贝叶斯同位素混合模型（MixSIAR）研究了高地温条件下地下水硫酸盐的来源和迁移过程。结果表明，受煤炭开采影响，煤层上下含水层之间的水力连通性显著。高地温条件加速了硫化物氧化和蒸发岩溶解，导致灰岩水中的硫酸盐浓度比正常地温煤矿高出数倍。此外，煤炭开采加速了地下水循环，强化了混合过程。同位素（δO和δS）与MixSIAR模型的联合应用表明，煤层下部灰岩水中的大部分硫酸盐源于蒸发岩溶解（39.60%），而砂岩水受混合过程影响显著，蒸发岩溶解（38.70%）和硫化物氧化（31.08%）起着同等重要的作用。这些发现为深部煤矿地下水资源的利用和管理提供了理论支持。
