To maximize the comprehensive utilization of gangue waste, broken gangue can be used to replace gravel as the coarse aggregate to prepare underground roadway shotcrete, and treated gangue powder can be used for the partial replacement of cement. This not only diminishes the demand for conventional raw materials but also increases the amount of gangue waste disposed. Broken gangue waste was ball-milled for 1 h, 3 h, and 5 h to prepare gangue powder, which was used to partially replace cement. Then, experimental schemes for the performance of shotcrete at the rates of cement replacement of 30%, 40%, and 50% were devised to compare the mineral compositions and microscopic characteristics of shotcrete with the partial replacement of cement with gangue powder. The influences of the partial replacement of cement with gangue powder on the slump, tensile strength, and compressive strength of the shotcrete were revealed. The experimental results revealed an inverse relationship between shotcrete slump and both the cement replacement ratio and the gangue Ball-milling duration. Increasing the cement replacement ratio from 30% to 50% reduced slump by 55.3% (103 mm → 46 mm), while extending the Ball-milling time from 1 h to 5 h decreased it by 33.0% (103 mm → 69 mm). Mechanical properties showed contrasting trends: After a 28-day curing process, compressive and tensile strengths declined by 54.5% (20.18 → 9.18 MPa) and 40.4% (1.56 → 0.93 MPa), respectively, with a higher cement replacement ratio. Conversely, prolonged Ball-milling duration improved the compressive strength by 12.8% (18.68 → 21.07 MPa) and the tensile strength by 34.1% (1.26 → 1.69 MPa). Moreover, the shotcrete meets the strength requirements for engineering applications only when the cement replacement ratio is 30% with gangue ball-milling durations of 3 h and 5 h. The research provides strong support for the performance optimization of gangue-based shotcrete and the improvement of the utilization of gangue waste.

In high-intensity mining operations in western China, shallow burial depths and rapid advancement rates induce rapid surface responses, significant deformation, and pronounced crack development. This study comprehensively evaluates these effects through full-process rock movement monitoring at the Jinjie coal mine, focusing on subsidence coefficients, mining coefficients, and inflection point trajectories. Results indicate that weak stability of the overlying strata in the shallow-buried working faces led to substantial surface subsidence, with a subsidence coefficient of 0.87, exceeding typical values (0.6–0.7) for conventional mining. The inflection point at the open-off cut followed a monotonic L-shaped trajectory, migrating laterally up to 4.7 times the mining height (15 m), while the inflection point near the roadway stabilized at 5.6–7.5 times the mining height (18–24 m) after two fluctuations. A significant contrast was observed in the horizontal movement coefficient between the goaf area (0.21–0.47) and the unmined area (1.59–2.38). Surface cracks exhibited an O-shaped ring distribution, synchronizing with periodic weighting intervals of 12–14 m; the pressure coefficient was approximately 1.73. Despite pronounced crack development, self-healing mechanisms reduced environmental risks. Full surface subsidence was achieved after the working face had advanced 320 m, a distance approximately equal to 1.24 times the working face length and 3.5 times the burial depth, with the basin areas occupying 48% of the total. Surface stabilization was achieved within 70 days (less than the ratio of burial depth to 100 m), underscoring the necessity of proactive measures such as crack filling to prevent air leakage and water inrush during rapid advancement (20 m/day).

Hydrothermal treatment has been demonstrated as a highly effective approach to enhance the adsorption properties of coal gangue (CG) for Cd²⁺ and Pb²⁺. This study evaluated the influence of NaOH concentration (X₁), hexadecyltrimethylammonium bromide dosage (X₂) and hydrothermal duration (X₃) on the modified CG’s composition and its adsorption capacities for Cd²⁺ (q_e,Cd) and Pb²⁺ (q_e,Pb). Response Surface Methodology (RSM) was utilized to explore the interactions among these variables, while XRD, SEM-EDX, FTIR and XPS techniques were employed to elucidate the adsorption mechanisms. The results reveal that hydrothermal treatment facilitated the formation of zeolite materials in the modified CG samples. Optimal conditions for Cd²⁺ adsorption (q_e,Cd = 58.4 mg/g) were determined as X₁ = 2.9 mol/L, X₂ = 1 g and X₃ = 16.8 h. For Pb²⁺ adsorption (q_e,Pb = 233.6 mg/g), the optimal conditions were X₁ = 2.4 mol/L, X₂ = 0.57 g and X₃ = 20.7 h. RSM analysis indicated that X₃ significantly influences q_e,Cd with the appropriate range of 14–18 h, while all three factors (X₁, X₂ and X₃) notably affect q_e,Pb, with suitable ranges identified as follows: X₁ = 1.8–3 mol/L, X₂ = 0.4–0.8 g and X₃ = 16–24 h. The primary adsorption mechanism for Cd²⁺ and Pb²⁺ was determined to be ion exchange, with additional Pb²⁺ removal achieved through the precipitation of cerussite (PbCO₃).

Amidst the intensifying challenges of global climate change and the increasing demand for regional sustainable development, accurately assessing the contributions and dynamic characteristics of different land-use types to regional carbon sink patterns is essential for understanding ecosystem carbon cycling mechanisms and optimizing carbon management strategies. Based on land-use and Net Primary Productivity (NPP) remote sensing data from 2018 to 2022, this study employs a land-use change coding method and a hydrothermal (temperature and precipitation) sensitivity coefficient approach to analyze the spatiotemporal variation in NPP in Guangxi Zhuang Autonomous Region and its differential responses to hydrothermal conditions. On this basis, sensitivity coefficients were calculated to assess the spatial patterns of NPP sensitivity to temperature and precipitation, revealing spatial sensitivity characteristics and potential ecological risks. The results indicate significant differences in NPP variations among different land-use types, with broadleaf forests, mixed forests, savannas, and croplands identified as the primary contributors to NPP flows. Additionally, the response of NPP to hydrothermal factors exhibits clear spatial heterogeneity: precipitation sensitivity hotspots are mainly concentrated in the northern and southern ecosystems, while temperature sensitivity hotspots are predominantly located in the northern region. Further analysis reveals that the ecosystems in the central and northern regions are more sensitive to temperature changes, whereas coastal areas exhibit higher stability.