Search Results (2,961)

This study develops an interpretable and calibrated XGBoost framework for probabilistic slope stability assessment using a 627-case database of circular-mode failures. Six predictors, namely, unit weight (γ), cohesion (c), friction angle (φ), slope angle (β), slope height (H), and pore-pressure ratio (rᵤ), were used to train a gradient-boosted tree model optimized through Bayesian hyperparameter search with five-fold stratified cross-validation. Physically based monotone constraints ensured that failure probability (P_f) decreases as c and φ increase and increases with β, H, and rᵤ. The final model achieved strong performance (AUC = 0.88, Accuracy = 0.80, MCC = 0.61) and reliable calibration, confirmed by a Brier score of 0.14 and ECE/MCE of 0.10/0.19. A 1000-iteration bootstrap quantified both epistemic and aleatoric uncertainties, providing 95% confidence bands for P_f-feature curves. SHAP analysis validated physically consistent influence rankings (φ > H ≈ c > β > γ > rᵤ). Predicted probabilities were classified into Low (P_f < 0.01), Medium (0.01 ≤ P_f ≤ 0.10), and High (P_f > 0.10) risk levels according to geotechnical reliability practices. The proposed framework integrates calibration, uncertainty quantification, and interpretability into a comprehensive, auditable workflow, supporting transparent and risk-informed slope management for infrastructure, mining, and renewable energy projects. Full article

Most risk assessment and source apportionment studies of the heavy metals in the surface soils in China have focused primarily on East China, whereas studies focused on Northwest China, particularly regarding heavy metals in surface soils in the central and western areas, remain limited. In this study, surface soils in the central–western Ali region were investigated, and the concentrations of nine heavy metals were determined. Moreover, the distribution patterns and ecological risks of these heavy metals were elucidated via a combination of the geoaccumulation index, pollution load index ($PLI$), comprehensive potential ecological risk index ($RI$), and integrated X-ray diffraction (XRD)–multivariate statistical techniques. Additionally, the pollution characteristics and sources were analyzed. The results indicated the following: (1) The spatial distribution of heavy metal pollution is closely linked to the geological background, and high–pollution zones (e.g., Cr, Ni, Co, Cu, As, and Cd) conform well with the distributions of ultramafic rocks and iron/chromite ore beds. The geoaccumulation index revealed that Cd caused slight and moderate contamination at 29.1% and 5.5% of the sites, respectively, whereas As affected 14.6% of the sites. The pollution load index indicated moderate pollution in 20% of the sites, and the potential ecological risk index indicated that 41.8% of the sites posed moderate risks, which was largely driven by Cd (mean $E_r^i$ = 43.1). The comprehensive ecological risk index ($RI$ = 115) confirmed a moderate risk level overall. Principal component analysis revealed three primary sources: natural weathering (Cr–Ni–Co–Cu, 39.1%); a mixed source influenced by nonagricultural anthropogenic activities such as transport and regional deposition, combined with natural processes such as arid climate and alkaline soil conditions that influence Cd mobility (Cd–Mo–Pb, 20.8%); and industrial/mining activities (As–Sb, 14.2%). Mineralogical analyses further indicated that heavy metals are present via lattice substitution, adsorption, and precipitation. This study systematically clarifies the composite pollution pattern and sources of heavy metals in the alpine Ali region, supporting targeted contamination control. Full article

In order to ensure the stability of the gravity heat pipe (GHP) heat exchanger in the mine return air waste heat recovery project and to explore the influence of the working fluid and filling ratio of the GHP on the heat transfer performance, this paper establishes a computational fluid dynamics (CFD) model of the GHP for mine return air waste heat recovery. The heat transfer characteristics and multiphase flow mechanism of the GHP with R22 and R410a working fluids at 30% to 80% filling ratios were studied using the VOF model from three aspects: two-phase flow, wall temperature, and thermal resistance. The validity of the model was verified through experimental data. The findings of the research indicate that the physical property parameters of the working fluid and the alterations in the filling ratio exert a substantial influence on the liquid-phase boiling heat transfer and the condensation process on the condenser wall. The CFD operation results demonstrate a high degree of congruence with the experimental data. The maximum deviation in the wall temperature is 2.9%. When the filling ratio is in the range of 50% to 60%, the axial distribution of the wall temperature tends to be flat. With regard to thermal resistance, both CFD and experimental results demonstrate a tendency of initially decreasing and subsequently increasing with increasing filling ratio. The average wall temperature of R410a GHP with a 50% filling ratio reached the highest value (20.3 °C), and the thermal resistance reached the lowest value (0.021 K/W), demonstrating superior heat transfer performance and excellent isothermal characteristics. Full article

Water and sand inrush is frequently accompanied by surface subsidence, which severely constrains the sustainable development of coordinated coal mining and ecological environment. This study investigated four key influencing factors based on a water and sand inrush test system: fracture width, aquifer thickness, sand particle size composition and stratigraphic sedimentary structure. It obtained the morphological evolution characteristics of collapse funnels and revealed the evolution mechanism of collapse funnels induced by water and sand inrush. The results indicate that fracture width and aquifer thickness mainly affect the range of collapse funnel, and both show a positive correlation with the radius of collapse funnels. Sandy particle size composition plays a dominant role in the morphology of collapse funnels induced by disasters: as the size of the soil skeleton particles increases, the morphology of collapse funnels changes sequentially from a bowl shape to an inverted cone shape and then to a funnel shape with a sunken center and raised slopes. The stratigraphic sedimentary structure has a significant impact on the morphology and damage induced by disasters in collapse funnels. The upper clay layer of the underlying aquifer inhibits the water and sand inrush processes to some extent. An increase in the thickness and number of clay layers effectively prevents the water and sand mixture from flowing into the fracture channel from the lateral direction. This reduces the damage range of collapse funnels and decreases the rate of water and sand inrush. This study clarifies the formation mechanism of surface collapse funnels under the influence of the disaster-causing factors of water and sand inrush, and provides theoretical guidance for the prevention and control of such disasters. Full article

As a support material for mine roadways, shotcrete (SC) exhibits performance limitations in extreme deep-mining environments characterized by high stress and water seepage. Polyoxymethylene (POM) fiber, with its properties of high strength, high modulus, and corrosion resistance, holds potential for application in surrounding rock support of deep roadways. To investigate the effect of POM fiber on the flexural performance of shotcrete, four-point bending tests were conducted on fiber-reinforced concrete specimens with different fiber lengths and dosages. Combined with ABAQUS numerical simulation, damage simulation analysis was performed on each group of specimens, and the stress propagation state of the fibers was tracked. The results show that the flexural strength of polyoxymethylene fiber shotcrete (PFS) increases with the increase in fiber length and dosage, and the influence of fiber dosage is more significant. POM fiber can effectively inhibit the crack development of shotcrete, enhancing its crack resistance and residual strength. The load-deflection curves indicate that PFS exhibits excellent fracture toughness, with the P9L42 group showing the highest flexural strength improvement, reaching an increase of 94%. The numerical simulation results are in good agreement with the experimental conditions, accurately reflecting the damage state and load-deflection response of each group of concrete specimens. Based on the above research, POM fiber is more conducive to meeting the stability requirements of roadway surrounding rock support, providing a scientific basis for the application of PFS in mine roadway surrounding rock support. Full article

The vitality of pollen significantly influences the efficiency of pollination and microspore embryogenesis. Mining genes associated with pollen vitality will help accelerate pepper (Capsicum annuum L.) breeding progress via genetic engineering. PEX (pollen extensin-like), a member of the LRX (leucine-rich repeat extensin) family, is predominantly expressed in pollen and participates in regulating pollen vitality. However, its function and regulatory factors in pepper remain elusive. In this study, GUS histochemical staining results revealed that pepper CaPEX3 could be expressed in petals, sepals, anthers, and pollens of transgenic tomato (Solanum lycopersicum L.) lines expressing CaPEX3 promoter::GUS. Moreover, inhibition of the CaPEX3 by virus-induced gene silencing (VIGS) in pepper resulted in reduced pollen germination rate and viability, while overexpression of CaPEX3 in tomato significantly enhanced germination rate and pollen viability. In addition, TRANSPARENT TESTA GLABRA 1 (CaTTG1) and Nuclear transcription factor Y subunit C9 (CaNFYC9) were screened out and identified as the upstream regulatory transcription factors of CaPEX3 through yeast one-hybrid (Y1H) screening and dual-luciferase reporter (Dual-LUC) assays. Taken together, the identification of transcription factors may reveal a more comprehensive mechanism underlying CaPEX3-mediated enhancement of pepper pollen viability. This study not only provides genetic resources for pollen viability research but also establishes a theoretical foundation for pepper breeding. Full article

The disposal of coal mine solid waste has always been a challenge in the coal mining production process, and the research and development of low-cost and high-performance filling materials is a prerequisite for achieving large-scale disposal of coal mine solid waste. The effects of water–cement ratio, foaming agent dilution ratio, foam agent content, foam stabilizer content, and gypsum content on the mechanical properties, transportation characteristics, and microstructure of cement foam filling materials were studied by laboratory test methods. The optimal ratio of cement foam filling material for comprehensive performance was determined. On this basis, the mechanism of influence of fly ash content, gangue content, and gangue particle size on the mechanics, transportation characteristics, and microstructure of foam filling materials was further studied. The experimental results show that at fly ash contents below 30%, gangue content is less than 30%. The particle size of gangue is less than 0.6 mm, and the expansion ratio of coal mine solid waste foam filling material is about three times, which has good mechanical properties and transportation performance. The on-site test results show that the control effect of the surrounding rock in the goaf is good, achieving safe and efficient mining of the working face. Full article

Subsidence over abandoned goaves is a primary trigger for secondary geological hazards such as surface collapse, landslides, and cracking. This threatens safe mining operations, impairs regional economic progress, and endangers local inhabitants and their assets. At present, goaf areas are mainly treated through grouting. However, owing to the deficiencies of traditional deformation monitoring methods (e.g., leveling and GPS), including their slow speed, high cost, and limited data accuracy influenced by the number of monitoring points, the surface deformation features of goaf zones treated with grouting cannot be obtained in a timely fashion. Therefore, this study proposes a method to analyze the spatio-temporal patterns of surface deformation in grout-filled goaves based on the fusion of Multi-temporal InSAR technologies, leveraging the complementary advantages of D-InSAR, PS-InSAR, and SBAS-InSAR techniques. An investigation was conducted in a coal mine located in Shandong Province, China, utilizing an integrated suite of C-band satellite data. This dataset included 39 scenes from the RadarSAT-2 and 40 scenes from the Sentinel missions, acquired between September 2019 and September 2022. Key results reveal a significant reduction in surface deformation rates following grouting operations: pre-grouting deformation reached up to −98 mm/a (subsidence) and +134 mm/a (uplift), which decreased to −11.2 mm/a and +18.7 mm/a during grouting, and further stabilized to −10.0 mm/a and +16.0 mm/a post-grouting. Time-series analysis of cumulative deformation and typical coherent points confirmed that grouting effectively mitigated residual subsidence and induced localized uplift due to soil compaction and fracture expansion. The comparison with the leveling measurement data shows that the accuracy of this method meets the requirements, confirming the method’s efficacy in capturing the actual ground dynamics during grouting. It provides a scientific basis for the safe expansion of mining cities and the safe reuse of land resources. Full article

Maintaining air quality is an important environmental challenge, affecting both urban and regional areas where industrial, agricultural, and energy activities intersect. The Upper Hunter Valley, NSW, experiences emissions from coal mining, power generation, agriculture, and wood fires, compounded by local meteorology, geology, and climate change. This study applies a political economy framework to examine historical governance structures including colonial legacies, institutional arrangements, and power relations and how they shape stakeholder roles and influence decision-making related to air quality. Technical applied research including improving dust monitoring, occupational health studies, and investigations into alternative fuels provided an empirical basis for identifying key stakeholders, including mining and energy companies, regulatory agencies, local councils, community groups, and environmental organisations. The analysis demonstrates how these actors influence governance processes, social licence to operate, and public perceptions of environmental risk. Findings indicate that effective air quality management requires multi-level, collaborative approaches that integrate technical expertise, regulatory oversight, and community engagement. The study highlights the importance of systemic strategies that align economic, environmental, and social objectives, providing insight into the governance of contested environmental resources in historically and politically complex regional contexts. This article is a rewritten and expanded version of the study “Analysis of air quality stakeholders in the Upper Hunter”, presented at the Clean Air conference, in Hobart, Australia, August 2024. Full article

This study presents a comprehensive review of the CLH index, a predictive tool developed to estimate the wear of tunnel boring machine (TBM) disc cutters operating in hard rock conditions. The CLH index provides a simplified, time-efficient, and cost-effective alternative to conventional wear prediction methods by employing a statistically derived empirical formula. The methodology is based on the identification and quantitative assessment of key rock properties that influence cutter wear. A detailed statistical analysis was conducted to validate the index, quantify potential errors, and determine confidence levels. As part of this review, updated reference tables are proposed to facilitate cutter wear estimation without the need for preliminary laboratory testing. These tables are derived from empirical data obtained at the Rock Mechanics Laboratory of the Higher Technical School of Mining and Energy Engineers (ETSIME-UPM), using operational records from TBM excavation in multiple Spanish high-speed railway tunnels, with a total length exceeding 120 km. The results confirm the reliability and practical applicability of the CLH index as a decision-support tool in TBM performance forecasting and maintenance planning. Full article

Underground coal mine conveying systems operate in unstructured environments. Influenced by geological and operational factors, coal conveyors are frequently contaminated by foreign objects such as coal gangue and anchor bolts. These contaminants disrupt conveying stability and pose challenges to safe mining operations, making their effective removal critical. Given the significant heterogeneity and unpredictability of these objects in shape, size, and orientation, precise manipulation requires dual-arm cooperative control. Traditional control algorithms rely on precise dynamic models and fixed parameters, lacking robustness in such unstructured environments. To address these challenges, this paper proposes a cooperative grasping method tailored for heterogeneous objects in unstructured environments. The MATD3 algorithm is employed to cooperatively perform dual-arm trajectory planning and grasping tasks. A multi-factor reward function is designed to accelerate convergence in continuous action spaces, optimize real-time grasping trajectories for foreign objects, and ensure stable robotic arm positioning. Furthermore, priority experience replay (PER) is integrated into the MATD3 framework to enhance experience utilization and accelerate convergence toward optimal policies. For slender objects, a sequential cooperative optimization strategy is developed to improve the stability and reliability of grasping and placement. Experimental results demonstrate that the P-MATD3 algorithm significantly improves grasping success rates and efficiency in unstructured environments. In single-arm tasks, compared to MATD3 and MADDPG, P-MATD3 increases grasping success rates by 7.1% and 9.94%, respectively, while reducing the number of steps required to reach the pre-grasping point by 11.44% and 12.77%. In dual-arm tasks, success rates increased by 5.58% and 9.84%, respectively, while step counts decreased by 11.6% and 18.92%. Robustness testing under Gaussian noise demonstrated that P-MATD3 maintains high stability even with varying noise intensities. Finally, ablation and comparative experiments comprehensively validated the proposed method’s effectiveness in simulated environments. Full article

Inner Mongolia is an important energy producer and the sixth-largest grain-supplying region in China. To address crucial water security challenges, the spatiotemporal variations in terrestrial water storage (TWS) and groundwater storage (GWS) in semiarid Inner Mongolia from April 2002 to January 2025 were evaluated on the basis of the synergistic use of multisource data, including satellite gravimetry, hydrological models, and meteorological data. There was a loss of TWS in Inner Mongolia (−1.69 ± 0.17 mm/year), which was caused mainly by the depletion of groundwater (−4.90 ± 0.12 mm/year), and it offset a slight increase in surface water (+3.21 ± 0.19 mm/year). Marked declines were clustered mainly in the central/southern regions (e.g., Ordos: GWS of −10.20 ± 0.19 mm/year), whereas the northeastern region (e.g., Hulun Buir) experienced an increase (+5.09 mm/year), which was related to abundant rainfall. Notably, the declining trend of GWS across all of Inner Mongolia before 2022 (−5.49 ± 0.17 mm/year) achieved an unprecedented reversal after 2022 (+17.80 ± 0.21 mm/year), indicating the significant influence of policy interventions and precipitation changes. In the central/eastern agro-pastoral zones, water loss was driven mainly by human-related activities such as coal mining and farming; in contrast, aridity in the west was worsened by climate variability. Therefore, it is crucial to formulate urgent water redistribution strategies, promote efficient irrigation methods, and improve monitoring systems for the purpose of protecting energy and food security and strengthening ecological adaptability in the context of climate change. Full article

With the weathering of iron sulfide minerals, acid rock drainage (ARD) emanates from the 60-millon tonne Main Waste Stockpile (MWS) at the Red Dog Mine. Following completion of the stockpile, a collection trench was constructed in 2012–2013 to capture and treat a portion of the ARD, and a cover system was emplaced from 2021 to 2025 to cover 90% of the stockpile. Select wells in the collection trench are associated with the different cover phases. Analysis of the water chemistry of samples collected at the wells indicates increased pH and decreased dissolved solids with each phase of the cover along with significant changes in flow and solutes such as aluminum, iron, sulfate, and zinc. Although the cover should continue to decrease ARD volume, acidity, and solute concentrations, an evaluation of historical acid production and iron sulfide consumption in the stockpile indicates a likely majority of the iron sulfide content remains available for weathering and acid production. Continued MWS ARD monitoring is necessary to evaluate the multi-year effect of the cover because of the variability of the pre-cover ARD, identification of seasonal and multi-year precipitation influences on ARD generation, and a yet to be determined influence of the cover on the volume of infiltrating precipitation. Full article

To optimize the support performance of rock bolts in high-stress environments, this study employs the ANSYS (Version 2022 R2) finite element numerical simulation method to systematically investigate the influence of bolt geometrical parameters (rib spacing, rib height, and bolt diameter) on the stress state of the anchoring system. A bolt–resin–sleeve model was established to analyze Mises equivalent stress distribution and peaks under a 150 kN pull-out load. The simulation results indicate that a rib spacing of 36 mm effectively promotes the diffusion of pre-stress into deeper regions, with peak stress in the bolt rod and resin ring increasing by 34.42% and 61.64%, respectively, compared to a spacing of 12 mm. Further increase in rib spacing provides limited enhancement in peak stress. A rib height of 1.0 mm achieves optimal system performance without excessively compromising the interfacial stress level. Increasing the diameter to 22 mm raised peak stress in the bolt, sleeve, and resin by 14.19%, 30.48%, and 50.77%, respectively, compared to 18 mm, balancing load capacity and material use efficiently. The optimal parameter set (36 mm spacing, 1.0 mm height, and 22 mm diameter) was validated in a field trial in Zhongmacun Mine’s 3903 East Transportation Bottom Drainage Roadway. Monitoring recorded maximum roof subsidence of 102.9 mm, stabilizing within 25 days (daily deformation < 0.2 mm), confirming the excellent performance of the bolt support system with this parameter combination in high-stress roadways. This study provides a theoretical basis and engineering reference for the optimal design of high-performance rock bolts. Full article

Sustainable mine geothermal energy causes high-temperature hazards in mine roadways, severely endangering miners’ lives. There is an urgent need to enhance research on the performance of composite phase change material (CPCM) roadway cooling systems, as they can effectively control ambient temperatures. However, existing research on CPCM roadway cooling system performance remains limited. This study innovatively establishes a numerical model for a novel cascade CPCM roadway cooling system and employs the control variable method to investigate the influence of multi-parameter regulation on system performance. The study reveals that the ring pipe radius ratio significantly impacts the system’s heat exchange efficiency and temperature distribution. The optimal comprehensive system performance is achieved at an annular tube radius ratio of 2:3, where the CPCM solid phase percentage for 89.03% and the average temperature of the monitoring surface decreases by 9.54 °C. Increasing the cascaded tube spacing enhances the overall cooling effect, but cooling efficiency diminishes when the spacing exceeds 0.5 m. The CPCM phase change temperature must align with the mine’s geothermal conditions, with CPCM utilization and cooling efficiency peaking at 25 °C. The air deflector structure effectively mitigates cooling lag in the lower roadway section. At an installation angle of 30°, the expansion distance of the lower low-temperature zone increased by up to 48.89% without compromising cooling efficiency in the upper roadway section, while also delaying the recovery rate of heat damage. Full article