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Zhou L, Ye T, Zheng S, Zhu X, Chen Z, Wu Y. Experimental and modeling investigation of dual-source iron release in water-solid-gas interaction of abandoned coal mine drainage. ENVIRONMENTAL GEOCHEMISTRY AND HEALTH 2023; 45:8433-8449. [PMID: 37634178 DOI: 10.1007/s10653-023-01731-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2023] [Accepted: 08/14/2023] [Indexed: 08/29/2023]
Abstract
After mine closure and flooding, abandoned iron-prone devices and equipment (e.g., steel bolts and ground support meshes) and iron-bearing minerals (e.g., pyrite) form a dual-source iron pollution system in mine groundwater. Dual-source iron contributes to the water-solid-gas interaction in abandoned coal mines and the release of iron at different periods after mine closure, posing environmental risks in groundwater and discharging acid mine drainage, which contains large amounts of iron. In this study, a series of hydrochemical experiments were conducted to simulate the iron release process of the dual-source system, and electrochemical experiments were carried out to reveal the reaction mechanism, characterize the dual-source iron pollution release mode and quantify the release rate ratio. PHREEQC package was used to simulate the long-term hydrogeochemistry reactions of the water-solid-gas interaction to determine the key factors and suitable conditions that inhibit dual-source iron release. The results show that the dual-source system of iron-bearing minerals (pyrite) and steel bolts promote iron release from each other. The resulting calculated annual iron release indicated that the overall iron release rate ratio is: dual-source > bolt > pyrite, indicating that mine water would remain acidic for a long time due to the continuous release of iron from the system. Numerical modeling results show that maintaining the environment temperature below 25 °C and the pH above 3.5 is an effective way to reduce the iron release rate.
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Affiliation(s)
- Lai Zhou
- Engineering Research Center of Ministry of Education for Mine Ecological Restoration, Xuzhou, 221116, China.
- School of Environmental Science and Spatial Informatics, China University of Mining and Technology, Xuzhou, 221116, China.
| | - Tao Ye
- Engineering Research Center of Ministry of Education for Mine Ecological Restoration, Xuzhou, 221116, China
- School of Environmental Science and Spatial Informatics, China University of Mining and Technology, Xuzhou, 221116, China
| | - Shuangshuang Zheng
- Engineering Research Center of Ministry of Education for Mine Ecological Restoration, Xuzhou, 221116, China
- School of Environmental Science and Spatial Informatics, China University of Mining and Technology, Xuzhou, 221116, China
| | - Xueqiang Zhu
- Engineering Research Center of Ministry of Education for Mine Ecological Restoration, Xuzhou, 221116, China
- School of Environmental Science and Spatial Informatics, China University of Mining and Technology, Xuzhou, 221116, China
| | - Zhongwei Chen
- School of Mechanical and Mining Engineering, the University of Queensland, St Lucia, QLD, 4072, Australia
| | - Yu Wu
- State Key Laboratory for Geomechanics & Deep Underground Engineering, Xuzhou, 221116, China
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