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Purpose: Over the past three decades, open-pit mining has been expanding in arid and semi-arid areas of China.Open-pit mining profoundly changes the soil environment and has a profound impact on the circulation of soil water in the aeration zone.Therefore, this research explores the impacts of open-pit coal mining on soil moisture processes in the semi-arid grasslands of Eastern Inner Mongolia Autonomous Region, China. Materials and methods: Soil samples were collected from depths of 0–500 cm at Shengli No. 1 open-pit mine's inner dump and a nearby natural grassland. These soil samples were analyzed for stable isotope characteristics ( δ 2 H , δ 18 O ) and moisture content. Collection of underground water samples inside and outside the mining area for conductivity analysis. Results and discussion: Soil evaporation loss in the mine's inner dump was significantly higher than in the grassland, with rates of 22.26% for δ 18 O and 6.61% for δ 2 H . The limiting depth of soil evaporation at the mine was found to be 260 cm, compared to 200 cm in the grassland. The increased underground water conductivity in the mine area was linked to heightened soil evaporation loss. Isotopic profiling of the soil indicated that the open-pit mining led to deeper preferential flow infiltration during heavy precipitation, reaching 280 cm in the mine area versus 220 cm in the grassland. Conclusions: The surface soil moisture content (SMC) increased due to mining activities intensified water-heat exchanges with the atmosphere, leading to more frequent and severe wet-dry cycles. This study provides a comprehensive understanding of open-pit mining's impact on SMC, evaporation, and infiltration in semi-arid areas, offering critical insights for ecological reclamation and sustainable mine construction. [ABSTRACT FROM AUTHOR]

Groundwater distribution influenced by mining activities is hard to be tracked due to the lack of accurate and real-time monitoring data. To address the groundwater dynamic change data under the mining conditions of open-pit coal mines, a three-dimensional automatic observation network of groundwater was constructed, and this observation network takes open-pit as the center, showing a radioactive distribution, based on hydrogeological conditions, and observes different aquifers. The data was analyzed by integrating hydrology, mining activity, and meteorological data. Analytic hierarchy process was adopted to reveal the underground disturbance influencing factors, and suggestions for groundwater protection were given. The results show that the dynamic variations of the groundwater with time can be divided into 3 types (precipitation affected, unaffected type, and mining affected types). The drainage operation during the open-pit mining triggered the drop of groundwater level, resulting in a cone of depression. The maximum drawdown of the central groundwater level was 60 m. And the disturbance mainly occurred in the mining area where the maximum groundwater disturbance radius was 8 km. Artificial drainage was the main disturbance factor of groundwater, and the range of groundwater level drop within the disturbance radius was closely related to the distance from the open-pit coal mine and the drainage volume. The closer the distance to the mines and the higher the drainage volume led to the deeper the groundwater level drop. This study shows the importance of the three-dimensional observation network of groundwater and provides a good reference for groundwater resources protection and ecological restoration in open-pit coal mines. [ABSTRACT FROM AUTHOR]

Abstract: Based on well correlation, division of sedimentary facies and microfacies, core observation, and analysis of rock thin sections, the authors comparatively analyzed the sedimentation and diagenesis of the oolitic beaches in the Puguang and Yuanba areas of northeastern Sichuan Basin, and expounded their control on reservoirs. In the Puguang area the oolitic beach is thick and lateral migration distance is short, intervals overlaid one another, while in the Yuanba area the oolitic beach is thin and lateral migration distance is long. The two areas both experienced various types of diagenesis. There happened intense early dissolution and wide-spread dolomitization in the oolitic beach of the Puguang area, where type-I reservoirs of high porosity and permeability are developed. In the Yuanba area, strong compaction and pressure dissolution, and late burial cementation led to the development of type-III reservoirs of low porosity and permeability. The main factors that control the sedimentation and diagenesis are paleotopography and changes in sea level. Sedimentation controls the distribution and thickness of reservoir, and diagenesis determines the porosity formation and evolution and ultimately the reservoir quality. [Copyright &y& Elsevier]