Geothermal energy is new, environmentally friendly, and clean energy, which is of great significance to realize energy saving and emission reduction. The study of the genesis mechanism of geothermal water is the key to its rational development and utilization. In this study, based on 14 sets of water samples from the eastern section of the copper well mining area of Yinan Gold Mine, mineral saturation index, isotope analysis (δ 18 O, δD), Si-enthalpy mixing equation, and geochemical geothermal temperature scale were used to analyze the thermal storage temperature, recharge characteristics, mixing ratio, circulation depth, and fluid passage to reveal the geothermal water fugitive transmission pattern and genesis mechanism in the study area and to propose a geothermal water genesis model. The study shows that the water supply elevation in the area is between 687.22 and 1164.15 m and a large amount of cold water recharged it. It is inferred that the recharge area is the precipitation in the Northwest Mountain range and surrounding atmosphere. Groundwater flows along the fracture zone in a south-easterly direction. It receives heating from the surrounding rocks, where the water level rises at the fracture zone intersection and is stored in the lower and middle Cambrian thermal reservoirs and continues to receive heating from deeper heat sources. Based on this study and previous regional research data, the fault structure in this area is within the influence range of the energy field of the Yishu fault zone. Yishu fault zone becomes the heating source under the background of cold water. It is inferred that the east−east Yishu fault zone in the study area may also be the recharge area.

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The sandstone aquifer is an important underground water storage space, and the study of its water abundance is of great significance to ensure the safety of underground engineering and to explore the occurrence mechanism of groundwater sources. Based on the correlation between geological characteristics and aquifer water abundance, this paper proposed an aquifer water abundance prediction model based on a cloud model that improved combination weighting. The model took the roof sandstone aquifer of the Qingshuiying Coalfield as an example and selected five basic geological indicators that are closely related to the water-rich influence degree of the aquifer as evaluation indicators. The model was based on the idea of game theory, combined the analytic hierarchy process (AHP) and the entropy weight method, and introduced the cloud model evaluation method. The establishment of the model was based on the idea of game theory, combining the AHP and the entropy weight method and introducing the cloud model evaluation method. The results show that most of the study areas are located in weak or relatively weak water abundance areas; relatively strong water abundance areas are mainly distributed in the central, western, and southeastern parts of the study; strong water abundance areas are scattered in parts of the northeast, southwest, and southeast. The unit water inflow data of the actual pumping test is consistent with the water-rich prediction partition, which proves the accuracy and scientificity of the method. The model provides a new idea for the study of groundwater geology and a new method for predicting the water abundance of the roof aquifer in coal mines.

The mining-induced water-conducting fracture zone (WCFZ) plays a critical role in roof water damage prevention and ecological protection. The measured heights of the WCFZ were collected from 52 working faces or boreholes in the Ordos Basin mining area. Four factors influencing the mining-induced height of the WCFZ, i.e., mining thickness, proportion coefficient of hard rock, working width, and mining depth, were analyzed. The optimal unitary function model of each factor and the height of the WCFZ were obtained through single-factor analysis. The grey correlation method and fuzzy ordered binary comparison method were used to determine the comprehensive weight, and the weighted improved multiple regression model was obtained by combination and iteration. The relative error of the model was basically controlled within 10%. Finally, taking the Qingshuiying Coalfield as an application case, we predicted the mining-induced height of the WCFZ by using the new prediction model. The spatial distribution characteristics of the WCFZ were analyzed by the geographic information system. In addition, Groundwater Modeling System (GMS) software was used to build a 3D structure model of WCFZ height to visualize the spatial distribution rules of the WCFZ. The results showed that the height of the WCFZ can be predicted quantitatively by this new method, and the visualization of the WCFZ can be realized. The proposed method effectively analyzes and predicts the mining-induced height of the WCFZ so that water gushing risks from overlying aquifers can be prevented or mitigated in mines.

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