Search Results (771)

The S11D mining complex in Brazil, situated in Pará state, extracts 20 million tons of iron each quarter. Connecting via a standard 802.11b/g/n wireless network is crucial for mine operations across vast distances. A local team employs a network monitoring tool called the Ekahau Site Survey to guarantee the proper functioning of the network. However, due to the harsh terrain and the dangerous nature of S11D operations, this tool fails to gather data from all points of interest, resulting in interpolated maps that may not accurately represent the network’s overall quality. In this work, we propose a platform that can be attached to mobile machines during operations to automatically collect network parameters, such as channelization, RSSI, latency, packet loss, and bandwidth, without requiring human intervention. Using these network data, we generate an RSSI map using Kriging, which the local team can use. Comparison tests conducted in the laboratory and the field demonstrate that the platform performs similarly to Ekahau in capturing network parameters, ensuring its use in day-to-day operations for mapping. Full article

Stabilisation of weak subgrades in mining and infrastructure projects traditionally relies on cement and lime, leading to high embodied energy and carbon emissions. Although waste glass powder (GP) has been explored in previous studies, existing work has primarily focused on isolated mechanical or material characteristics, with limited emphasis on integrated performance metrics. This study addresses this gap by establishing a mechanical–energy–carbon evaluation framework for assessing GP as a low-carbon stabiliser for black cotton (BC) and kaolinite clay (KC) soils. Laboratory investigations were conducted to evaluate the index, compaction, strength, and swelling characteristics at GP dosages ranging from 0% to 20%. Results showed a marked decrease in liquid limit (from 76% to 61% for BC and 45% to 32% for KC) and optimum moisture content, accompanied by a concurrent increase in maximum dry density. Strength improved substantially, with UCS reaching 95 kN/m² (BC) and 100 kN/m² (KC) at 15% GP. CBR values increased threefold, while DFSI decreased by 45–75%, indicating improved volumetric stability. Energy accounting revealed an 80–85% lower embodied energy compared to cement, with carbon savings of approximately 52 kg CO₂/t. The proposed Energy Performance Index confirmed superior strength per unit energy efficiency of GP. Valorising post-consumer glass aligns with circular economy principles and UN SDGs 9, 12, and 13, offering a low-carbon stabilisation strategy for energy-efficient mining operations. Full article

The coal mining subsidence area constitutes a distinct ecotone in the transition from agricultural soil to sediment, yet the microbially mediated nitrogen cycle within it remains inadequately understood. This investigation comprehensively analyzed physicochemical properties, microbial communities, functional genes, and co-occurrence networks along a 0–6500 mm depth gradient. Results indicated that pH transitioned from acidic to alkaline, while TN, TP, OM, and NH₄⁺–N accumulated with depth. NO₃⁻–N decreased rapidly within 1000 mm and then stabilized. Alpha-diversity showed an S-shaped increase in richness, with Shannon index peaking at 1500 mm. Beta-diversity shifted along PC1, and the shallow subsidence area (SS) influenced by NO₃⁻–N; the transition zone (TZ) regulated by OM, TN, and NH₄⁺–N; deep subsidence area (DS) was constrained by TP and pH. Microbial communities transitioned from aerobic/facultative to strictly anaerobic phyla, yet Pseudomonadota remained dominant (24–32%) across depths. With increasing depth, gene abundances for denitrification, assimilatory nitrate reduction to ammonium (ANRA), and nitrate assimilation declined, while those for dissimilatory nitrate reduction to ammonium (DNRA) and nitrification increased; nitrogen fixation remained weak. Co-occurrence networks shifted from highly connected, short-pathlength, and clustered in TZ to highly modular and long-pathlength in DS, with Aminicenantes, Syntrophus, and Methanoregula as key taxa. Overall, the thick and stable reducing zone in the subsidence area restructured the nitrogen cycle, shifting terminal products from N₂ removal to NH₄⁺ retention. These findings advance the understanding of nitrogen transformation in soil-sediment ecotones and provide a mechanistic framework for nitrogen cycling in mining-affected ecosystems. Full article

Online reviews on platforms such as Google Maps strongly influence consumer decisions. However, aggregated ratings mask nuanced opinions about specific aspects such as food, drinks, service, lounge, and price. This study presents a multi-aspect sentiment analysis framework for Arabic café reviews. Specifically, we combine machine learning (Linear SVC, Naïve Bayes, Logistic Regression, Decision Tree, Random Forest) and a Convolutional Neural Network (CNN) to perform aspect identification and sentiment classification. A rigorous preprocessing and feature-engineering with TF-IDF and n-gram was implemented and statistically validated through bootstrap confidence intervals and Friedman–Nemenyi significance tests. Experimental results demonstrate that Linear SVC with optimized TF-IDF tri-grams achieved a macro-F1 of 0.89 for aspect identification and 0.71 for sentiment classification. Meanwhile, the CNN model yielded a comparable F1 of 0.89 for aspect identification and a higher 0.76 for sentiment classification. The findings highlight that effective feature representation and model selection can substantially improve Arabic opinion mining. The proposed framework provides a reliable foundation for analyzing Arabic user feedback on location-based platforms and supports more interpretable and data-driven business insights. These insights are essential to enhance personalized recommendations and business intelligence in the hospitality sector. Full article

Carbon dioxide (CO₂) is the most significant anthropogenic greenhouse gas (GHG), accounting for approximately 81% of total emissions, with methane (CH₄), nitrous oxide (N₂O), and fluorinated gases contributing the remainder. Rising atmospheric CO₂ concentrations, driven primarily by fossil fuel combustion, industrial processes, and transportation, have surpassed the Earth’s natural sequestration capacity, intensifying climate change impacts. Carbon Capture, Utilization, and Storage (CCUS) offers a portfolio of solutions to mitigate these emissions, encompassing pre-combustion, post-combustion, oxy-fuel combustion, and direct air capture (DAC) technologies. This review synthesizes advancements in CO₂ capture materials including liquid absorbents (amines, amino acids, ionic liquids, hydroxides/carbonates), solid adsorbents (metal–organic frameworks, zeolites, carbon-based materials, metal oxides), hybrid sorbents, and emerging hydrogel-based systems and their integration with utilization and storage routes. Special emphasis is given to CO₂ mineralization using mine tailings, steel slag, fly ash, and bauxite residue, as well as biological mineralization employing carbonic anhydrase (CA) immobilized in hydrogels. The techno-economic performance of these pathways is compared, highlighting that while high-capacity sorbents offer scalability, hydrogels and biomineralization excel in low-temperature regeneration and integration with waste valorization. Challenges remain in cost reduction, material stability under industrial flue gas conditions, and integration with renewable energy systems. The review concludes that hybrid, cross-technology CCUS configurations combining complementary capture, utilization, and storage strategies will be essential to meeting 2030 and 2050 climate targets. Full article

Reservoirs are hotspots for the coupling of nutrients and heavy metals, and they substantially modify the compositions and spatiotemporal distributions of microorganisms in fluvial systems. However, relatively few studies have been performed that investigate the microbial mechanisms driving interactions among heavy metals and nutrients in reservoirs. The Goupitan Reservoir, a seasonal stratified reservoir located within the Wujiang River catchment, was chosen as the research subject. The temporal and spatial variations in heavy metals and nutrients, and the metagenomic composition of the reservoir water were analyzed in January, April, July, and October 2019. The results revealed that As, Ni, Co, and Mn were derived primarily from mine wastewater, whereas Zn, Pb, Cd, and Cr were related to domestic and agricultural wastewater discharge. The study area was dominated by Proteobacteria, Actinobacteria, Cyanobacteria, and Bacteroidetes, with the proportion of dominant phyla reaching 90%. Decreases in the dissolved oxygen (DO) concentration and pH in the bottom water during July and October were conducive to increases in the abundance of the anaerobic bacterial groups Planctomycetes and Acidobacteria. The functional genes norBC and nosZ associated with denitrification (DNF), the key gene nrfAH involved in the dissimilatory nitrate reduction to ammonium (DNRA) process, the functional genes aprAB and dsrAB responsible for sulfate reduction/sulfide oxidation, as well as the thiosulfate oxidation complex enzyme system SOX, all exhibit high abundance in hypoxic water bodies and peak in the redoxcline, highlighting the significance of related nitrogen (N) and sulfur (S) metabolic processes. In addition, the concentrations of heavy metals significantly affected the spatial differentiation of the planktonic bacterial community structure, with Mn, Co, Fe, Ni, As, and Cu making relatively high individual contributions (p < 0.01). This study is important for elucidating the sources and microbiological mechanisms influencing heavy metals and nutrients in seasonally stratified subtropical reservoirs. Full article

Mining activities have led to contamination of natural resources by heavy metals (HMs). Biomagnification studies of HMs within food webs are necessary for understanding the progressive increase in metal burdens across trophic levels and their potential ecotoxicological consequences. This study examined the trophic transfer of Cd, Cu, Pb, and Zn in a tri-trophic model involving maize plants (Zea mays), their herbivore, the grasshopper Sphenarium purpurascens, and their predator, the spider Neoscona oaxacensis, under controlled conditions. Samples from all individuals were collected in Huautla, Morelos, Mexico, where three tailing deposits are present, containing approximately 780,000 tons of waste rich in HMs. We evaluated the body biomass of the grasshopper and the percentage of maize leaf material consumed with and without HMs. HM bioaccumulation in maize, grasshopper, and spider tissues was analyzed, and the enrichment process, along with gender related effects on HM bioaccumulation in females and males of S. purpurascens, was studied. The results revealed enrichment of Pb, Cd, and Cu in maize leaf tissue, except for Zn. Grasshoppers exhibited biomagnification of the same metals, except for Cd. Metal bioaccumulation resulted in a reduced biomass of female and male grasshoppers, accompanied by an increased leaf consumption compared to grasshoppers fed maize leaves without HMs. The HMs’ bioaccumulation levels differed between genders, with males recording significantly higher concentrations of Zn and Pb. The excretion of HMs in feces and their bioaccumulation in exoskeletons are two efficient metal detoxification strategies in grasshoppers. This study revealed biomagnification in the spider N. oaxacensis, confirming metal biomagnification to higher trophic levels and providing critical insight into exposure pathways, risks to wildlife and humans, and how metal pollutants may disrupt ecosystem integrity. Full article

Current coal mine fire risk assessments often rely on static models and isolated factors, failing to capture the complex, dynamic interactions that lead to fires. To address this gap, we propose a comprehensive framework—termed INK-FBSD—integrating Interpretive Structural Modeling (ISM), the NK model, fuzzy Bayesian network analysis, and System Dynamics (SD) simulation. Using ISM, we identified and hierarchically structured 31 risk factors across human, equipment, environment, management, and fire protection domains, revealing that a robust mine safety accountability system is a pivotal root factor. The NK model quantifies how accident likelihood escalates as more factors interact—for example, four-factor couplings (e.g., equipment–environment–management–fire protection) yield significantly higher risk indices (T ≈ 0.34) than two-factor scenarios. The fuzzy Bayesian analysis estimates an overall 46% probability of a fire accident under current conditions, and diagnostic inference pinpoints excessive coal dust accumulation and neglected fire prevention as top contributors when an incident occurs (posterior probabilities 83% and 78%, respectively). Finally, SD simulations show how key risk factors (such as equipment failure and maintenance delays) can rapidly elevate to severe risk levels within 9–15 months without intervention, underscoring the need for continuous monitoring and proactive control. In summary, the INK-FBSD approach provides a multidimensional understanding of coal mine fire mechanisms and delivers practical guidance for safety management by prioritizing critical risk factors, anticipating high-risk coupling pathways, and informing more effective fire prevention and emergency response strategies. Full article

N-tetradecanoyl-L-homoserine lactone (C₁₄-HSL) is a long-chain signaling molecule belonging to acyl-homoserine lactones (AHLs), which is widely present in the quorum sensing (QS) system of Gram-negative bacteria. In this study, the effects of C₁₄-HSL on chalcopyrite bioleaching mediated by Acidithiobacillus ferrooxidans (A. ferrooxidans) were investigated. After cultivating A. ferrooxidans with different energy substrates and exploring the potential mechanisms of signal molecule production, chalcopyrite was selected as the energy substrate for further study. Molecular docking analysis revealed that the high binding affinity between AHL and the receptor protein AfeR in A. ferrooxidans was beneficial for the activation of transcription by the AfeR-AHL complex, promoting their biological impact. The variations in the physicochemical parameters of pH, redox potential, and copper ions revealed that after adding C₁₄-HSL, the leaching rate of chalcopyrite increased (1.15 times during the initial 12 days). Further analysis of the mechanism of extracellular polymers formation indicated that the presence of C₁₄-HSL could promote the formation of biofilms and the adhesion of bacteria, facilitating mineral leaching rate of A. ferrooxidans. This research provides a theoretical basis for regulating the biological leaching process of chalcopyrite and metal recovery using signaling molecules, which could also be used to control environmental damage caused by acid mine/rock drainage. Full article

Coal-free zones, particularly scouring zones, reduce recoverable reserves and increase water inrush risk in coal mining. Existing sedimentological, geophysical, and geostatistical methods are often constrained by coring conditions, lithological interpretation accuracy, and geological complexity. Given that well log signals provide the most continuous carriers of geological information, this study integrates Singular Spectrum Analysis (SSA), Maximum Entropy Spectral Analysis (MESA), and Integrated Prediction Error Filter Analysis (INPEFA) to establish a multi-curve framework for analyzing the genesis and logging responses of coal-free zones. A two-stage SSA workflow was applied for noise reduction, and a Trend–Fluctuation Composite (TFC) curve was constructed to enhance depositional rhythm detection. The minimum singular value order (N), naturally derived from SSA-decomposed INPEFA curves, emerged as a quantitative indicator of mine water inrush risk. The results indicate that coal-free zones resulted from inhibited peat-swamp development followed by fluvial scouring and are characterized by dense inflection points and frequent cyclic fluctuations in TFC curves, together with the absence of low anomalies in natural gamma-ray logs. By integrating multi-curve logs, core data, and in-mine three-dimensional direct-current resistivity surveys, the genetic mechanisms and boundaries of coal-free zones were effectively delineated. The proposed framework enhances logging-based stratigraphic interpretation and provides practical support for working face layout and mine water hazard prevention. Full article

Nutrient cycling has barely been studied in acidic environments and may have an important influence on the evolution of the microbial communities. In this research, we studied nutrient sources and fluxes in acidic metal-mine pit lakes to evaluate their relationship with the lakes’ microbial ecology. Nutrient concentrations (including phosphorus, nitrogen, and dissolved inorganic carbon) increase with depth in all the studied pit lakes. Phosphorus comes mainly from the leaching of the host rock and is rapidly scavenged from the aqueous phase in the oxygenic and Fe(III)-rich mixolimnion due to adsorption on ferric precipitates (schwertmannite, jarosite), which leads to an important P-limitation in the photic zone. Below the chemocline, however, the sum of phosphorus inputs (e.g., settling of algal biomass, desorption from the ferric compounds, microbial reduction of Fe(III)-sediments) sharply increases the concentration of this element in the anoxic monimolimnion. Nitrogen is very scarce in the host rocks, and only a limited input occurs via atmospheric deposition followed by N-uptake by algae, N-fixation by acidophilic microorganisms, sedimentation, and organic matter degradation in the sediments. The latter process releases ammonium to the anoxic monimolimnion and allows some nitrogen cycling in the chemocline. Soluble SiO₂ in the mixolimnion is abundant and does not represent a limiting nutrient for diatom growth. Differences in phytoplankton biomass and extent of bacterial sulfate reduction between relatively unproductive lakes (San Telmo) and the more fertile lakes (Cueva de la Mora) are likely caused by a P-limitation in the former due to the abundance of ferric iron colloids in the water column. Our results suggest that phosphorus amendment in the photic zone could be an efficient method to indirectly increase acidity-consuming and metal-sequestering bacterial metabolisms in these lakes. Full article

This study explores how outdoor environments in cold-region university campuses influence students’ physical and mental health, addressing the lack of research on health-oriented campus design under cold climatic conditions. Drawing on Evidence-Based Design (EBD) theory and the Socio-Ecological Model (SEM), a Multi-Factor Analysis (MFA) framework integrating theoretical analysis, data mining, and empirical validation was developed to reveal the mechanisms linking campus environmental factors and student health. Through a systematic literature review and Latent Dirichlet Allocation (LDA) topic modeling, six key factors—climate adaptability, architectural layout, infrastructure, natural landscape, safety, and transportation accessibility—were identified and further verified through questionnaire data (N = 480) for reliability and validity. The Delphi method was then used to refine the indicator system and determine factor weights, while case studies of representative cold-region universities proposed optimization strategies from the dimensions of built environment, climatic adaptation, and perceived environment. The findings enrich the application of socio-ecological theory in health-oriented campus research and provide scientific and practical guidance for planning and promoting healthy university environments in cold regions. Full article

The erodibility of natural cohesive sediments and artificial mixtures was investigated through controlled laboratory experiments and used as a basis to discuss seabed mobility and suspended particulate matter on the Continental Shelf adjacent to a river mouth. Changes in the erodibility of cohesive seabeds can influence resuspension and erosion rates and impact suspended particulate matter dispersion patterns and even the benthic community. For the experiments, sediment samples with sand content ranging from 0% to 90% were tested using an erosion testing chamber to evaluate the relationships among sand content, settling, consolidation, critical shear stress, and erosion rate. Critical shear stress values ranged from 0.31 to 0.42 N/m², and erosion rates varied up to 30 times between the most mud-rich and sand-rich samples. Natural samples exhibited lower erodibility, evidenced by higher critical shear stress and lower erosion rates compared to Industrial Clay, highlighting the role of organic matter in enhancing sediment stability. Additionally, although the sand addition reduced the critical shear stress required for sediment motion, it resulted in lower erosion rates. Results were also compared with sediment samples collected from the Continental Shelf adjacent to the Doce River mouth, a region impacted by a large-scale mining tailings spill in 2015. Although the frequency of sediment mobilization did not differ significantly between pre- and post-disaster conditions, mud-rich sediments exhibited greater erosion potential once the threshold was surpassed. This suggests that the dam failure impacted the sediment dynamics of the Continental Shelf adjacent to the Doce River mouth. These findings can be used to improve sediment transport models and environmental management strategies in disturbed coastal systems. Full article

The Yanlinsi gold deposit, located in the middle section of the Jiangnan Orogenic Belt, is one of the typical gold deposits in northeastern Hunan Province. Diabase dikes are exposed by underground workings and drill holes in the mining area. The dikes strike NW and cut the NE-trending gold ore body. To investigate the petrogenetic age, characteristics of the magmatic source area, and tectonic setting of the diabase dikes in the Yanlinsi gold mining area, northeastern Hunan, and to determine the mineralization age of the deposit, in this paper, diabase dike LA-ICP-MS zircon U-Pb dating, whole-rock geochemistry, and gold-bearing quartz vein LA-ICP-MS zircon U-Pb dating were studied. The results of LA-ICP-MS zircon U-Pb dating indicate that the diabase was emplaced at an age of 219.5 Ma, belonging to the late Indosinian. The investigated diabase dikes are characterized by low SiO₂ (43.68%–46.55%), high MgO (7.78%–9.84%), and high Mg# (65.0–68.7) values, belonging to the alkaline basalt series with high potassium. The chondrite-normalized REEs patterns show highly fractionated LREEs and HREEs ((La/Yb)_N = 11.21–14.82), and the primitive mantle-normalized spider patterns show enrichment in large ion lithophile elements (e.g., Rb, Ba, K and Sr) and relative depletion in high field strength elements (e.g., Nb, Ta, and P), similar to those of ocean island-like basalt (OIB). Rock geochemical characteristics indicate that the magma of the Yanlinsi diabase was formed by partial melting of the enriched mantle (EM II), with the source region being spinel-garnet lherzolite. The degree of partial melting was approximately 10%–15%, and the assimilation and contamination with continental crustal materials were weak. Meanwhile, weak fractional crystallization of olivine, clinopyroxene, and apatite occurred during the magma evolution process. On the basis of a synthesis of previous research results, it is concluded that the Yanlinsi diabase formed in an extensional tectonic setting after intracontinental collisional orogeny. The LA-ICP-MS U-Pb age of hydrothermal zircons from quartz veins in the main mineralization stage of the Yanlinsi gold deposit is 421.9 ± 1.5 Ma. Combined with the cross-cutting relationships between mafic dikes and gold veins (ore bodies), it is determined that the main mineralization stage of the deposit formed during the Caledonian Period. Full article

Gel materials are widely used in underground mining for air leakage sealing and coal spontaneous combustion prevention. In this study, a novel self-healing carboxymethyl cellulose-modified amphiphilic polymer hydrogel with fire prevention and extinguishing capabilities is synthesized through ionic crosslinking between CMC-graft-poly(AM-co-NaA-co-BAM) and aluminum citrate (AlCit). The copolymer is constructed by grafting sodium carboxymethyl cellulose (CMC) onto an amphiphilic polymer backbone composed of acrylamide (AM), sodium acrylate (NaA), and N-benzylacrylamide (BAM), forming a dual-network structure via hydrophobic association and hydrogen bonding. The carboxymethyl cellulose-modified amphiphilic polymer demonstrates optimal viscosity-enhancing performance at a CMC content of 7.5 wt%. CMC-graft-poly(AM-co-NaA-co-BAM) demonstrated superior temperature, shear, and salt resistant performance compared with poly(AM-co-NaA-co-BAM), poly(AM-co-NaA), and CMC polymers, as well as enhanced viscoelasticity and self-healing capability. When crosslinked with AlCit, CMC-graft-poly(AM-co-NaA-co-BAM)-AlCit gel demonstrated superior viscoelastic properties and self-healing capability, as well as thermal stability, which gave the superior fire prevention and extinguishing performance for charcoal in fire extinction tests. CMC-graft-poly(AM-co-NaA-co-BAM) has abundant cross-linking sites, which lead to accelerated gelation and improved mechanical strength, while the hydrophobic microdomains acted as physical cross-linking points that interconnected polymer chains into a three-dimensional network. The hydrophobic interactions within the hydrogel are dynamically reversible. This intrinsic property allows physical cross-links to spontaneously reassociate when fracture surfaces make contact. Consequently, the material exhibits autonomous self-healing. Full article