With the increasing number of closed mines, the geological environment problems around closed mines have become increasingly prominent, especially in terms of soil pollution. In this paper, a total of 32 topsoil samples were collected from Qianling closed coal mine and the contents of Cu, Zn, Co, Cr, Mn, As, Cd and Pb were analyzed. The results indicated that the contents Zn and As exceeded the surface soil background values of Anhui Province. Compared with the soil of production mines, the contents of Pb and Zn were higher. The assessment results of pollution and ecological risk of soil based on Nemerow index, Geological accumulation index and potential ecological risk assessment method showed that the closed coal mine was in the mild to moderate pollution and mild hazard ecological risk. The Pearson correlation and positive matrix decomposition model were applied to identify the sources of soil heavy metals, which included atmospheric dustfall (22.47%), natural factors (22.51%), agricultural activities (4.40%), transportation (8.90%) and industrial emissions (42.08%), respectively.

Hydrochemistry of groundwater is important in coal mines because it can be used for understanding water–rock interaction and inrush water source identification. In this study, major ion concentrations of groundwater samples from the loose layer aquifer (LA), coal-bearing aquifer (CA) and Taiyuan Formation limestone aquifer (TA) in the Qingdong coal mine, northern Anhui province, China, have been analyzed by a series of statistical methods for identifying the source of chemical constituents in groundwater and the source of inrush water. The results indicate that the mean concentration of the major ions in the LA were ordered as follows: HCO3− > SO42− > Na+ + K+  > Cl− > Ca2+ > Mg2+ > CO32−, whereas average values of the CA in decreasing order are SO42−, Na+ + K+, HCO3−, Cl−, Ca2+, Mg2+ and CO32−, and the major ion concentrations of the TA have the following order: SO42− > Na+ + K+ > Ca2+  > HCO3− > Cl− > Mg2+ > CO32−, and most of the samples are Na-SO4 and Ca-SO4 types. TDS content in water increases with aquifer depth, whereas the pH values ranged from 7.1 to 8.9, indicating a weak alkaline environment. Two sources (weathering of silicate minerals and dissolution of evaporate minerals) have been identified by principal component analysis responsible for the chemical variations of the groundwater, and their contribution ratios have been quantified by Unmix model. Moreover, based on the Q-mode cluster and discriminant analyses, the samples with known sources have been identified correctly to be 95.7% and 97.6%, respectively, and the samples with unknown sources have been determined with high probability (78–100%).

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The surface water from subsidence lake and shallow groundwater play an important role for agriculture, industry and local communities in coal mining areas. The connection between two type water and quality, however, remains unclear. In this study, 37 samples were collected from subsidence lake and shallow groundwater around Luling coal mine. The hydrogeochemisty data and formation mechanisms were analyzed to reveal the connection proof. Compared with shallow groundwater, the surface water from subsidence lake have a higher content of Na+ and HCO3−. For two type water samples, Na+ and Mg2+ are two most abundant cations, followed by Ca2+. The contents of anions followed the same order: HCO3− > SO42− > Cl−. The water samples were controlled by NaHCO3 (99.3%) type. The chemical composition of two type water were similar, which are all mainly influenced by silicate minerals weathering and ion-exchange interactions, among which ion-exchange interactions was more intense than in shallow groundwater. The recharging source of two type water mainly came from atmospheric precipitation. The two water in the study area, in general, showed the risk of high salt and low-moderate alkali damage. The outcomes provide a better understanding of subsidence lake and groundwater and it will help for utilization of water resources.

Based on the hydro-geological conditions of 1028 mining face in Suntuan Coal Mine, mining seepage strain mechanism of seam floor was simulated by a nonlinear coupling method, which applied fluid-solid coupling analysis module of FLAC 3D . The results indicate that the permeability coefficient of adjoining rock changes a lot due to mining. The maximum value reaches 1 379.9 times to the original value, where it is at immediate roof of the mined-out area. According to the analysis on the seepage field, mining does not destroy water resistance of the floor aquiclude. The mining fissure does not conduct lime-stone aquifer, and it is less likely to form damage. The plastic zone does not exactly correspond to the seepage area, and the scope of the altered seepage area is much larger than the plastic zone.