PAPER
Using stable isotopes (δD, δ
18
O, δ
34
Sand
87
Sr/
86
Sr) to identify sources
of water in abandoned mines in the Fengfeng coal mining district,
northern China
Shen Qu
1,2
&
Guangcai Wang
1,2
&
Zheming Shi
1,2
&
Qingyu Xu
1,2
&
Yuying Guo
1,2
&
Luan Ma
1,2
&
Yizhi Sheng
1,2
Received: 16 November 2017 /Accepted: 16 May 2018
#
Springer-Verlag GmbH Germany, part of Springer Nature 2018
Abstract
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
(δDandδ
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 manage-
ment in this area and other similar mining areas.
Keywords Stable isotopes, mining
.
China
.
Water sources
.
Hydrochemistry
Introduction
In recent years, increasing numbers of coal mines in China
have been closed as coal resources were depleted or mining
geological conditions deteriorated. With the cessation of
pumping, groundwater levels and hydrostatic pressure in the
abandoned underground mines increase; this goaf water poses
a safety threat to neighboring active mining operations (Dong
et al. 2013) and a source of pollution to groundwater re-
sources, as mine waters are often characterized by low pH
and high total dissolved solids (TDS), Fe, Mn
2+
and associat-
ed trace metals (Cravotta 2008;Fengetal.2013; Sheng et al.
2016; Nordstrom et al. 2015). In this connection, understand-
ing the source of mine water and the nearby groundwater
system is very important in order to manage and/or prevent
pollution dispersion.
Hydrogeochemical approaches have been widely applied
to identify the sources of abandoned mine water (Wang et al.
2016;Luetal.2014; Huang and Chen 2012; Guo et al. 2016a,
b). Additionally, stable isotopes have served as an effective
tracer to determine the source of water and pollutants. For
instance, the hydrogen and oxygen isotopes method has been
commonly used to estimate the source of mine water based on
the differences in δDandδ
18
O from various sources (Luo et
al. 2015; Ye and Shen 1989;Duanetal.1994; Dou et al. 2011;
Zdzisław et al. 2013). Strontium in the form of Sr
2+
and the
Published in the special issue BGroundwater sustainability in fast-
developing China^
* Guangcai Wang
wanggc@pku.edu.cn
1
State Key Laboratory of Biogeology and Environmental Geology &
MOE Key Laboratory of Groundwater Circulation and Evolution,
China University of Geosciences, Beijing 100083, China
2
School of Water Resources and Environment, China University of
Geosciences, Beijing 100083, China
Hydrogeology Journal
https://doi.org/10.1007/s10040-018-1803-5
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