Groundwater-Mixing Mechanism in a Multiaquifer System Based on Isotopic Tracing Theory: A Case Study in a Coal Mine District, China

• Published in: Geofluids 2018-01, Vol.2018 (2018), p.1-10
• Main Authors: Huang, Pinghua, Wang, Xinyi
• Format: Article
• Language: English
• Subjects: Analysis; Aquifers; Biodegradation; Calcium; Calcium ions; Cambrian; Carbon 14; Case studies; Coal; Coal industry; Coal mines; Coal mining; Coastal plains; Curvature; Environmental testing; Exploitation; Geochemistry; Groundwater; Hydrology; Isotopes; Isotopic tracers; Karst; Limestone; Magnesium; Management; Methanogenic bacteria; Mixing ratio; Organic chemistry; Permeability; Precipitation; Quaternary; Rain; Rain and rainfall; Rainfall; Sandstone; Sedimentary rocks; Studies; Surface water; Tracers; Trends; Water; Water analysis; Water inrush; Water sampling; Water, Underground
• ISSN: 1468-8115; 1468-8123
• DOI: 10.1155/2018/9549141

Water inrush of mixed groundwater is the primary threat against safe production in coal mines. To study the mixing mechanism of a multiaquifer groundwater system, groundwater samples were collected from different strata in a typical North China-type coalfield (Chaochuan Coal Mine) and were then tested using environmental isotopes (18O, 2H, 3H, 13C, and 14C) and hydrochemical ions (Ca2+, Mg2+, Na+, K+, HCO3−, SO42−, and Cl−) as tracer agents. Results demonstrate that HCO3− and Cl− exhibit a linear relationship with the mixing ratio, whereas Na+, Ca2+, and SO42− show certain degrees of curvature. This condition indicates that groundwater mixing involves major chemical actions. The δD–δ18O plot reveals that karst water and groundwater from Quaternary and sandstone aquifers are mainly mixtures of local rainfall, evaporated groundwater, and “palaeo-groundwater.” The 3H