A significant amount of open-pit-mine broken sandstone (OMBS) is produced during open-pit mining. The mechanical strength of the loose sandstone is critical for ensuring dump slope stability and sustainable mine construction. This study investigates the modification of OMBS using artemisia sphaerocephala krasch (ASK) gum to enhance its engineering properties. Unconfined compressive strength, shear strength and permeability tests were conducted to quantitatively analyze the modification effect. And the stability was evaluated using FLAC3D simulation methods. The modification mechanism was characterized through SEM, FT-IR, XRD. The results demonstrated that the addition of 2 % ASK gum significantly improved OMBS mechanical performance and reduced permeability. Meanwhile, the failure mode of OMBS changed with the ASK gum content increasing. The simulation result indicated the stability of modified dump slope was better under the drying-wetting cycle. From the perspective of microstructure and chemical characteristics, the addition of ASK gum created new hydrogen bonds through intermolecular interactions with the hydrophilic groups between OMBS particles and formed a dense and stable structure through three reinforcement modes: surface encapsulation, pore filling, and bonding connection. This study provides a new idea for resource saving and environmentally friendly mining area development.

PurposeOver 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 methodsSoil 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 (delta 2H,delta 18O\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${\delta 2 H, \delta {18} O}$$\end{document}) and moisture content. Collection of underground water samples inside and outside the mining area for conductivity analysis.Results and discussionSoil evaporation loss in the mine's inner dump was significantly higher than in the grassland, with rates of 22.26% for delta 18O\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${\delta {18} O}$$\end{document} and 6.61% for delta 2H\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${\delta 2 H}$$\end{document}. 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.ConclusionsThe 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.

Quantitatively evaluating the ecological environment impacts of vegetation destruction due to open-pit mining activities is vital for enhancing the green mining standard and cost management capabilities of mining enter-prises. Based on the Landsat time series, this study proposes an ecological environment impact assessment and quantitative characterization method for vegetation destruction in mining areas resulting from open-pit mining activities. First, the modified normalized difference water index and the normalized difference vegetation index time series data were calculated. The water body thresholds and the fraction of vegetation coverage were ascertained using the K-means clustering algorithm and the dimidiate pixel model, respectively, to determine the area of direct vegetation destruction in mining areas. Second, utilizing the Theil-Sen Median trend analysis and the Mann-Kendall test, the indirect impact area of vegetation in the mining region was identified. Lastly, by integrating vegetation's net primary productivity with the Chinese Emission Allowance price index, the total carbon emission cost of vegetation destruction due to mining activities over 20 years was calculated to be about 2.122 million yuan. The findings indicated that the ecological environmental impact of open-pit mining activities on vegetation destruction cannot be ignored. From 2000 to 2020, open-pit mining at the Wulishan limestone mine in Anhui Province, China, increased the area of direct vegetation destruction by 9.072 x 105 m2, and the indirect impact area on vegetation was 7.371 x 105 m2. The carbon emission cost of vegetation destruction in the direct destruction area was about 104,000 yuan per year, and the carbon emission cost of vegetation damage in the indirect impact area was approximately 2,082.53 yuan per year. This research provides a scientific foun-dation for ecological environmental protection, regulations, green mining, and cost management for mining enterprises, promoting the harmonious progress of both the economy and environmental protection.