Search Results (82)

Coal gangue, a major by-product of coal mining, poses significant environmental challenges due to its large-scale accumulation, land occupation, and potential for air and water pollution. This manuscript presents a comprehensive overview of continuous chamber gangue storage technology as a sustainable mining solution for coal mines. The principles of this approach emphasize minimizing disturbance to overlying strata, enabling uninterrupted mining operations, and reducing both production costs and environmental risks. By storing the surface or underground gangue in continuous chambers, the proposed method ensures the roof stability, maximizes the waste storage, and prevents the interaction between mining and waste management processes. Detailed storage sequences and excavation methods are discussed, including continuous and jump-back excavation strategies tailored to varying roof conditions. The process flows for both underground and ground-based chamber storage are described, highlighting the integration of gangue crushing, paste preparation, and pipeline transport for efficient underground storage. In a case study with annual storage of 500,000 t gangue, the annual economic benefit reached CNY 1,111,425,000. This technology not only addresses the urgent need for sustainable coal gangue management, but also aligns with the goals of resource conservation, ecological protection, and the advancement of green mining practices in the coal industry. Full article

The occurrence of haze pollution significantly deteriorates air quality and threatens human health, yet persistent knowledge gaps in real-time source apportionment of fine particulate matter (PM_2.5) hinder sustained improvements in atmospheric pollution conditions. Thus, this study employed single-particle aerosol mass spectrometry (SPAMS) to investigate PM_2.5 sources and dynamics during winter haze episodes in Yinchuan, Northwest China. Results showed that the average PM_2.5 concentration was 57 μg·m⁻³, peaking at 218 μg·m⁻³. PM_2.5 was dominated by organic carbon (OC, 17.3%), mixed carbonaceous particles (ECOC, 17.0%), and elemental carbon (EC, 14.3%). The primary sources were coal combustion (26.4%), fugitive dust (25.8%), and vehicle emissions (19.1%). Residential coal burning dominated coal emissions (80.9%), highlighting inefficient decentralized heating. Source contributions showed distinct diurnal patterns: coal combustion peaked nocturnally (29.3% at 09:00) due to heating and inversions, fugitive dust rose at night (28.6% at 19:00) from construction and low winds, and vehicle emissions aligned with traffic (17.5% at 07:00). Haze episodes were driven by synergistic increases in local coal (+4.0%), dust (+2.7%), and vehicle (+2.1%) emissions, compounded by regional transport (10.1–36.7%) of aged particles from northwestern zones. Fugitive dust correlated with sulfur dioxide (SO₂) and ozone (O₃) (p < 0.01), suggesting roles as carriers and reactive interfaces. Findings confirm local emission dominance with spatiotemporal heterogeneity and regional transport influence. SPAMS effectively resolved short-term pollution dynamics, providing critical insights for targeted air quality management in arid regions. Full article

The global climate crisis necessitates the urgent implementation of sustainable practices and carbon emission reduction strategies across all sectors. Transport, as a major contributor to greenhouse gas emissions, requires transitional technologies to bridge the gap between fossil fuel dependency and renewable energy systems. Natural gas, recognised as the cleanest fossil-derived fuel with approximately half the CO₂ emissions of coal and 75% of oil, presents a potential transitional solution through Natural Gas Vehicles (NGVs). This manuscript presents several distinctive contributions that advance the understanding of Natural Gas Vehicles within the contemporary energy transition landscape while synthesising updated emission performance data. Specifically, the feasibility and sustainability of NGVs are investigated within the energy transition framework by systematically incorporating recent technological developments and environmental, economic, and infrastructure considerations in comparison to conventional vehicles (diesel and petrol) and unconventional alternatives (electric and hydrogen-fuelled). The analysis reveals that NGVs can reduce CO₂ emissions by approximately 25% compared to petrol vehicles on a well-to-wheel basis, with significant reductions in NO_x and particulate matter. However, these environmental benefits depend heavily on the source and type of natural gas used (CNG or LNG), while economic viability hinges largely on governmental policies and infrastructure development. The findings suggest that NGVs can serve as an effective transitional technology in the transport sector’s sustainability pathway, particularly in regions with established natural gas infrastructure, but require supportive policy frameworks to overcome implementation barriers. Full article

Background: The integration of mining and urban spaces in coal-resource-based cities holds significant implications for urban transformation and sustainable development. However, existing research lacks an in-depth analysis of its characteristics and driving factors. Methods: This study takes the central urban area of Huaibei City as a case, utilizing historical documents, POI data, and spatial analysis methods to explore the evolution patterns and influencing factors of mining–urban spatial integration. Standard deviation ellipse analysis was employed to examine historical spatial changes, while a binary logistic regression model and principal component analysis were constructed based on 300 m × 300 m grid units to assess the roles of 11 factors, including location, transportation, commerce, and natural environment. Results: The results indicate that mining–urban spatial integration exhibits characteristics of lag, clustering, transportation dominance, and continuity. Commercial activity density, particularly leisure, dining, and shopping facilities, serves as a core driving factor. Road network density, along with the areas of educational and residential zones, positively promotes integration, whereas water surface areas (such as subsidence zones) significantly inhibit it. Among high-integration areas, Xiangshan District stands as the most economically prosperous city center; Lieshan–Yangzhuang mining area blends traditional and modern elements; and Zhuzhuang–Zhangzhuang mining area reflects the industrial landscape post-transformation. Conclusions: The study reveals diverse integration patterns under the synergistic effects of multiple factors, providing a scientific basis for optimizing spatial layouts and coordinating mining–urban development in coal-resource-based cities. Future research should continue to pay attention to the dynamic changes of spatial integration of mining cities, explore more effective integrated development models, and promote the rational and efficient use of urban space and the sustainable development of cities. Full article

Active and abandoned mining sites are significant sources of heavy metals and metalloid pollution, leading to serious environmental issues. This study assessed the environmental risks posed by potentially toxic elements (PTEs), specifically arsenic (As) and antimony (Sb), in the Technosols (mining residues) of the former Pejão coal mine complex in Northern Portugal, a site impacted by forest wildfires in October 2017 that triggered underground combustion within the waste heaps. Our methodology involved determining the “pseudo-total” concentrations of As and Sb in the collected heap samples using microwave digestion with aqua regia (ISO 12914), followed by analysis using hydride generation-atomic absorption spectroscopy (HG-AAS). The concentrations of As an Sb ranging from 31.0 to 68.6 mg kg⁻¹ and 4.8 to 8.3 mg kg⁻¹, respectively, were found to be above the European background values reported in project FOREGS (11.6 mg kg⁻¹ for As and 1.04 mg kg⁻¹ for Sb) and Portuguese Environment Agency (APA) reference values for agricultural soils (11 mg kg⁻¹ for As and 7.5 mg kg⁻¹ for Sb), indicating significant enrichment of these PTEs. Based on average I_geo values, As contamination overall was classified as “unpolluted to moderately polluted” while Sb contamination was classified as “moderately polluted” in the waste pile samples and “unpolluted to moderately polluted” in the downhill soil samples. However, total PTE content alone is insufficient for a comprehensive environmental risk assessment. Therefore, further studies on As and Sb fractionation and speciation were conducted using the Shiowatana sequential extraction procedure (SEP). The results showed that As and Sb levels in the more mobile fractions were not significant. This suggests that the enrichment in the burned (BCW) and unburned (UCW) coal waste areas of the mine is likely due to the stockpiling of lithic fragments, primarily coals hosting arsenian pyrites and stibnite which largely traps these elements within its crystalline structure. The observed enrichment in downhill soils (DS) is attributed to mechanical weathering, rock fragment erosion, and transport processes. Given the strong association of these elements with solid phases, the risk of leaching into surface waters and aquifers is considered low. This work underscores the importance of a holistic approach to environmental risk assessment at former mining sites, contributing to the development of sustainable remediation strategies for long-term environmental protection. Full article

The roughness of haul roads significantly impacts fuel consumption in open-pit coal mine trucks, yet there is currently a lack of quantitative road classification methods in this regard. This study proposes a fuel-efficient road classification methodology for open-pit coal mines. Using UAV-captured point cloud data of mine roads as the basis for roughness analysis and the International Roughness Index (IRI) as the evaluation metric, the research establishes linear relationships between IRI and fuel consumption for both loaded and unloaded trucks. The K-means clustering algorithm is employed to classify road quality into “good”, “moderate”, and “poor” categories, with the Haerwusu Open-pit Coal Mine serving as a case study. Results demonstrate that 150 m represents an appropriate IRI segmentation interval for Haerwusu, with IRI thresholds of 12 (15) and 20 (21) serving as critical segmentation points for loaded (unloaded) trucks. From analyzing two end-slope roads in the case study mine we found that upgrading “poor” roads to “moderate” quality could reduce fuel costs by 3% for loaded trucks and 2% for unloaded trucks. This study provides a quantitative road classification method for open-pit coal mines, offering a theoretical foundation for reducing transportation costs and promoting sustainable mining development. Full article

This study investigates the annual carbon emission disparities between privately-owned electric vehicles (EVs) and internal combustion engine vehicles (ICEVs) by developing a usage-phase life cycle assessment (LCA) model, with a focus on the synergistic impacts of grid carbon intensity, driving intensity (e.g., annual mileage), and vehicle energy efficiency. Through scenario analyses and empirical case studies in four Chinese megacities, three key findings are obtained: (1) Grid carbon intensity is the primary factor affecting the emission advantages of EVs. EVs demonstrate significant carbon reduction benefits in regions with low-carbon power grids, even when the annual mileage is doubled. However, in coal-dependent grids under intensive usage scenarios, high-energy-consuming EVs may experience emission reversals, where their emissions exceed those of ICEVs. (2) Higher annual mileage among EV owners (1.5–2 times that of ICEV owners) accelerates carbon accumulation, particularly diminishing per-kilometer emission advantages in regions where electricity grids are heavily reliant on fossil fuels. (3) Vehicle energy efficiency heterogeneity plays a critical role: compact, low-energy EVs (e.g., A0-class sedans/SUVs) maintain emission advantages across all scenarios, while high-energy models (e.g., C-class sedans/SUVs) may exceed ICEV emissions even in regions with low-carbon power grids under specific conditions. The study proposes a differentiated policy framework that emphasizes the synergistic optimization of grid decarbonization, vehicle-class-specific management, and user behavior guidance to maximize the carbon reduction potential of EVs. These insights provide a scientific foundation for refining EV adoption strategies and achieving sustainable transportation transitions. Full article

Underground coal mines face increasing challenges in the scheduling of Electric Rubber-Tired Vehicles (ERTVs) due to confined spaces, dynamic production demands, and the need to coordinate multiple constraints such as complex roadway topologies, strict time windows, and limited charging resources in the context of clean energy transitions. This study presents a Constraint Programming (CP)-based optimization framework that integrates Virtual Charging Station Mapping (VCSM) and sensor fusion positioning to decouple spatiotemporal charging conflicts and applies a dynamic topology adjustment algorithm to enhance computational efficiency. A novel RFID–vision fusion positioning system, leveraging multi-source data to mitigate signal interference in underground environments, provides real-time, reliable spatiotemporal coordinates for the scheduling model. The proposed multi-objective model systematically incorporates hard time windows, load limits, battery endurance, and roadway regulations. Case studies conducted using real-world data from a large-scale Chinese coal mine demonstrate that the method achieves a 17.6% reduction in total transportation mileage, decreases charging events by 60%, and reduces vehicle usage by approximately 33%, all while completely eliminating time window violations. Furthermore, the computational efficiency is improved by 54.4% compared to Mixed-Integer Linear Programming (MILP). By balancing economic and operational objectives, this approach provides a robust and scalable solution for sustainable ERTV scheduling in confined underground environments, with broader applicability to industrial logistics and clean mining practices. Full article

Ammonia is gaining increasing attention as a zero-carbon fuel and hydrogen carrier, offering high energy density, mature liquefaction infrastructure, and strong compatibility with existing energy systems. This review presents a comprehensive summary of the recent advances in ammonia-based clean energy systems. It covers the fuel’s physicochemical properties, green synthesis pathways, storage and transport technologies, combustion behavior, NO_X formation mechanisms, emission control strategies, and safety considerations. Co-firing approaches with hydrogen, methane, coal, and DME are evaluated to address ammonia’s low reactivity and narrow flammability limits. This paper further reviews engineering applications across power generation, maritime propulsion, and long-duration energy storage, drawing insights from current demonstration projects. Key technical barriers—including ignition delay, NO_X emissions, ammonia slip, and economic feasibility—are critically examined. Finally, future development trends are discussed, highlighting the importance of integrated system design, low-NO_X combustor development, solid-state storage materials, and supportive policy frameworks. Ammonia is expected to serve as a strategic energy vector bridging green hydrogen production with zero-carbon end-use, facilitating the transition to a sustainable, secure, and flexible energy future. Full article

The scarcity of natural aggregates and the growing accumulation of waste materials have driven the demand for sustainable and circular economy solutions in transportation infrastructure, and this has led to the utilization of waste materials in transport infrastructure, such as recycled rubber. Although numerous laboratory experiments have been conducted on granular mixtures mixed with rubber, predicting the complex stress–strain behaviour of these mixtures mathematically and capturing the influence of rubber on the geotechnical properties of waste mixtures are imperative. This paper presents a comprehensive review of the constitutive models developed to predict the stress–strain behaviour, dilatancy, and shear strength of rubber-mixed waste materials, including sand–rubber, coal wash–steel furnace slag–rubber crumbs, and coal wash–rubber crumbs in various transport infrastructure applications under static loading. This paper also highlights the innovations and limitations of these existing constitutive models on rubber-mixed materials. It was found that existing constitutive models based on hyperbolic, hypoplastic, critical state, and bounding surface plasticity approaches can capture the behaviour of these materials under static loading conditions. However, further developments are required to incorporate the influence of the type and size of the rubber, particle breakage, and damping properties and also account for train-induced cyclic loading in models developed for railway substructures. This paper contributes to advancing future research aimed at deepening the fundamental understanding of rubber-mixed materials used in transportation infrastructure. Full article

Tianjin is a typical industrialized city of 13.64 million people, and the urbanization rate is 85.49%. The risk of heavy metals in the soils of the typical agricultural land around Tianjin poses a significant challenge to the sustainability of the ecosystem’s health and human health. Different heavy metals in different land-use types in Tianjin have all accumulated in the soils, and the vegetable base had the highest total of accumulated heavy metals. This study took the surface soil of farmland Xiqing District—the main vegetable and crop area in Tianjin—as the research object, and the concentrations of eight heavy metals were analyzed. The geo-accumulation index (I_geo), principal component analysis (PCA), absolute principal component score-multiple linear regression (APCS–MLR), positive definite matrix factorization (PMF), and health risk assessment model were used to evaluate the degree, sources, and health risks (to adults and children) of heavy metal pollution. This study compares the APCS–MLR model with the PMF model. The results showed that Cd and Hg pollution were the most severe among the eight heavy metals in agricultural soil, with the average values exceeding the background by 151.9% and 324.1%, respectively. About 15% of the sites were at moderate to severe pollution levels. The PMF model can better analyze the sources of heavy metals in the study area, showing that the main sources of heavy metal pollution include natural source, mixed source of agriculture and transportation, coal combustion source, and pesticide source. The total carcinogenic risk index (TCR) of natural source is the highest, with Cr being the main contributor to maximum total non-carcinogenic risk indices (HI) and TCR for children; Hg contributes the most to HI in the coal combustion source, while Cu and Zn contributes most in the mixed source of agriculture and transportation. Full article

This study examines the policy and technological dynamics shaping China’s road transport sector’s transition to low-carbon sustainability, focusing on battery electric vehicles (BEVs) and hydrogen fuel cell electric vehicles (HFCEVs). As the world’s second-largest carbon emitter, China faces significant challenges in reducing its fossil fuel dependency in road transport, which accounts for diverse emissions and energy security risks. The present work, using a dual tech multi-level perspective (DTMLP) framework integrating multi-level perspective (MLP) and an advocacy coalition framework (ACF), analyzes the interplay of landscape pressures (global carbon constraints), regime dynamics (policy–market interactions), and niche innovations (BEV/FCEV competition). The results reveal BEVs’ dominance in light-duty markets, achieving remarkable operational emission reductions but facing lifecycle carbon lock-ins from battery production and coal-dependent power grids. HFCEVs demonstrate potential for heavy-duty decarbonization but struggle with gray hydrogen reliance and infrastructure gaps. Policy evolution highlights shifting governance from subsidies to market-driven mechanisms, alongside regional disparities in implementation. This study proposes a three-phase roadmap: structural optimization (2025–2030), technological adaptation (2030–2045), and hydrogen–electric system integration (post-2045), emphasizing material innovation, renewable energy alignment, and multi-level governance. Our findings underscore the necessity of coordinated policy–technology synergies, grid decarbonization, and circular economy strategies, to overcome institutional inertia and achieve China’s ‘Dual Carbon’ targets. This work provides actionable insights for global sustainable transport transitions amid competing technological pathways and geopolitical resource constraints. Full article

In pursuit of sustainable development, worldwide adoption of hydrogen fuel cell vehicles (HFCVs) is growing to cut carbon emissions in the transportation sector. The construction of hydrogen refueling stations (HRSs) is the key to popularizing HFCVs. The popularity of HRSs is hindered by cost, site selection, and user expectations. Selecting mature gas stations with large passenger flow to expand HRSs can improve the accuracy of the hydrogen refueling network. Reducing the range anxiety of HFCV users to improve the path coverage of HFCVs is a favorable way to expand the hydrogen vehicle industry chain. Therefore, this study proposes a bi-level programming model, which considers hydrogen source (HS), hydrogen delivery mode (HDM), initial remaining range, range anxiety, and other factors. The upper-level model is designed to optimize economic costs, including the total chain cost of the HRS. The lower level aims to optimize the range anxiety of HFCV users and more accurately reflect their autonomy by controlling the maximum remaining range of the vehicle. Finally, the expressway in the Liaoning Province of China is taken as an example to verify that the optimization model had the advantages of low hydrogen cost and minimal range anxiety. The cost analysis of several HSs and HDMs was discussed from the perspective of the best site selected, and it was found that the Anshan HS using coal to produce hydrogen and the long tube trailer can provide lower hydrogen cost for the HRS. This method is generalizable to other regions or all types of HFCVs. Full article

Combustion is a key method for converting energy, historically relying on fossil fuels like coal and oil, which have significant drawbacks for sustainable development. Ammonia (NH₃) is highlighted as a viable hydrogen carrier with high hydrogen content, easy liquefaction, and better transportation characteristics compared to hydrogen. Despite its potential, ammonia combustion faces challenges such as NOx emissions and combustion performance, necessitating further research into its combustion dynamics. This systematic review is geared towards encapsulating the latest advancements in the research and development initiatives pertaining to ammonia fuel combustion, with a particular emphasis on elucidating the chemical kinetics and strategies for controlling nitrogen oxide emissions, and delineates the technical hurdles and prospective research avenues associated with ammonia combustion. Full article

Biomass pellets are increasingly recognized as a cost-effective and sustainable renewable energy source worldwide. However, comprehensive sustainability assessments of their production processes are scarce. To address this gap, three distinct scenarios in Northeast China were evaluated using emergy, economic, and environmental analysis methods: corn single production, corn–pellet co-production, and pellet production. A modified method for calculating the environmental loading rate (ELR) was proposed, which accounts for the environmental benefits associated with replacing coal with biomass pellets for heating. The results showed that corn–pellet co-production demonstrates superior energy efficiency compared to corn-only production, but presents a contrasting economic profile. The ELR for corn single production and corn–pellet co-production are 1.57 and 1.63, respectively, with corresponding emergy sustainability indices (ESI) of 0.89 and 0.84. After applying the modified method, the ELR and ESI for corn–pellet co-production were adjusted to 0.84 and 1.63, respectively, and the ESI of pellet production increased from 8.24 to 21.15. Furthermore, processing corn straw into biomass pellets for heating can reduce heating costs by approximately USD 254.26/hm² and reduce emissions of SO₂, NO_x, CO, PM_2.5, and CO₂ by 9.12, 19.82, 580.31, 65.86, and 13,060.66 kg/hm², respectively. Sensitivity analysis revealed that transportation distance and renewable electricity have a greater impact on pellet production than corn–pellet co-production. The ESI for pellet production decreases from 21.15 to 14.02 as transport distance increases from 20 km to 100 km, while it rises to 57.81 as the proportion of renewable energy in the power supply increases from 0% to 100%. Full article