Search Results (52)

Mining activities are characterised by a multiplicity of inherent occupational hazards. Exposure to mineral dust such as silica, asbestos, and coal dust is common in mining, leading to pneumoconiosis. Exposure to respirable silica-containing dust is one of the common respiratory hazards associated with adverse health effects such as silicosis, lung cancer, renal failure, scleroderma, systemic lupus erythematosus (SLE) and chronic obstructive pulmonary disease (COPD), to mention but just a few. In southern Africa, there is a rising epidemic of silicosis, human immunodeficiency virus (HIV) and tuberculosis (TB). Excessive exposure to silica-containing dust exacerbates the TB and silicosis epidemic in mining areas. There is poor control of dust exposure and a lack of occupational hygiene assessments of silica dust in mining in southern Africa. In southern Africa, there remains a persistent knowledge gap regarding the extent of occupational exposures to respirable chemical substances, such as silica dust. Consequently, occupational hygiene air monitoring was conducted in mining companies across four low-income Southern Africa Development Community (SADC) countries, Lesotho, Mozambique, Malawi and Zambia, to provide a baseline exposure dataset. The hazardous nature of work associated with mining activities still persists in these low-income countries, with 53% (n = 72) of quarries and 20% (n = 19) of coal mines having respirable quartz exposures exceeding the reference occupational exposure limit (OEL) of 0.1 milligrams per cubic meter (mg/m³). The highest exposure ranges for quartz were recorded in surface aggregate quarries, with the maximum concentration recorded at 2.739 mg/m³. The highest number of air samples (93%, n = 111), which were in compliance with the OEL of 3 mg/m³ for respirable dust, were recorded in the copper, diamond, ruby, cement quarry and gold mines. This exploratory study confirms the variable extent of mineworker exposure to respirable dust and corresponding quartz fractions emanating from different mining activities. The collected exposure data provides a baseline overview of exposures within the mining industry in the SADC region. It also serves as a vital input for future regional exposure surveillance databases, as well as preliminary data for directing future research towards regional exposure prevention initiatives. Full article

This paper presents the numerical modeling and experimental testing of steel-reinforced columns composed of three types of concrete: reinforced cement concrete (RCC), geopolymer concrete (GPC), and geopolymer concrete incorporating quarry rock dust (GPCD). GPC columns were produced using fly ash (FA) and furnace slag (SG) in equal proportions (50% each), with the addition of 0.75% steel fibers by volume. In GPCD columns, 20% of SG was replaced with quarry rock dust (QRD). A total of twenty columns (200 mm × 200 mm × 1000 mm), designed for a compressive strength of 40 MPa (fc’), were tested under static loading. The experimental data were validated using finite element (FE) modeling in ABAQUS, where the Concrete Damaged Plasticity (CDP) model was adopted to describe concrete behavior. Calibration of the FE model for the control specimen was carried out by adjusting viscosity parameters, dilation angles, shape factors, plastic potential eccentricity, stress ratios, and mesh sizes. The calibrated control model was then employed for comparative analysis and validation against experimental results. For concentrically loaded columns, the predicted axial load and axial and lateral deflection responses closely matched the experimental observations. However, for eccentrically loaded columns, the FE model over-predicted the load-carrying capacity as well as axial and lateral deflections. The experimental findings indicate that both GPC and GPCD columns exhibited lower load-carrying capacities compared to RCC columns; however, the inclusion of steel fibers enhanced their performance. Overall, the proposed FE model demonstrated a good agreement with experimental observations, providing a reliable framework for predicting the structural behavior of geopolymer-based columns. Full article

This study investigates how natural fillers of different origins and morphologies influence the structural, thermal, rheological, and mechanical properties of thermoplastic elastomers (TPEs). Two series of materials were prepared: one based on a biobased matrix, poly(butylene 2,5-furandicarboxylate)-block-poly(tetramethylene oxide) (PBF-PTMO), and one based on a petroleum-derived matrix, poly(butylene terephthalate)-block-poly(tetramethylene oxide) (PBT-PTMO). Both series incorporated a range of natural modifiers, i.e., lignocellulosic fibers and ground fractions of Arundo donax L., cyanobacterial biomass (Spirulina platensis), and silica-rich mineral dust originating from volcanic stone quarries. The materials were obtained via melt blending, while the reference matrices (neat block copolymers) were synthesized through melt polycondensation. The chemical structure and limiting viscosity number (LVN) of the neat matrices were confirmed, while differential scanning calorimetry (DSC) provided insight into their morphology and phase composition. Scanning electron microscopy (SEM) was employed to evaluate the morphology and distribution of the modifiers within the polymer matrices. To assess how the fillers influenced processing windows and performance, thermogravimetric analysis (TGA), oscillatory rheological measurements, and tensile testing were performed. The results provide insight into structure–property relationships governing natural filler–TPE interactions and support the development of more sustainable elastomeric composites with tailored performance. Full article

The growing need for a cleaner, sustainable environment has increased interest in reusing waste materials that cause pollution. In this research, the mechanical (dry density, compressive, and tensile strength) and also durability properties (sorptivity, rate of water absorption, chloride ion resistance, and resistance to freeze–thaw) of concrete were studied by partially substituting cement with brick powder (BP) and sand with quarry dust (QD). The proportions of brick powder replacement with cement were in the range of 5%, 10%, 15%, and 20% by weight. Likewise, QD was used in the range of 15%, 30%, 45%, and 60% by weight of natural sand. Both materials were used separately as well as simultaneously in concrete. Concrete mixtures were prepared, tested after curing, and then compared with conventional concrete. The water–cement (w/c) ratio was kept constant at 0.55 for all the mixes. According to experimental results, the concrete made with brick powder and quarry dust resulted in improved dry density. After curing for 28 and 56 days, the compressive and splitting tensile strengths increased by substituting cement with brick powder up to 15%. Brick powder showed a higher strength activity index than required according to the standard. Also, compressive and splitting tensile strengths significantly increased by replacing natural sand with quarry dust up to 60% at all curing ages. Combined mixes with partial replacements of cement and sand with brick powder and quarry dust, respectively, also showed improvements in the compressive and splitting tensile strength at all ages. Sorptivity and rate of water absorption decreased with the addition of BP and QD. Moreover, brick powder and quarry dust mixes showed higher resistance to chloride ion penetrability and higher resistance to freeze–thaw as the replacement level increased. Microstructural analysis of hard concrete samples also confirmed the enhanced mechanical strength and durability due to brick powder and quarry dust. Full article

This study introduces a Blasting Safety Index (BSI), a composite analytical framework for quantifying the cumulative mechanical, environmental, and geotechnical effects of quarry blasting operations. The index integrates ground vibration expressed as Peak Particle Velocity (PPV), noise, dust concentration, and slope stability, each normalized and weighted according to its operational relevance, to provide a unified measure of blasting-related risk. Field application in a pyroxenic andesite quarry is presented as a demonstrative pilot case illustrating the internal coherence and operational feasibility of the proposed framework and resulted in a BSI value of 0.91, classifying the operation as high risk despite full compliance with individual regulatory thresholds. Within the applied weighting structure, PPV represented the dominant contribution to the composite index, reflecting its widely documented influence on blast-induced safety outcomes. The proposed methodology offers a transparent, measurement-based decision-support tool for operational control, regulatory communication, and environmental impact assessment. Owing to its compatibility with digital monitoring ecosystems, the BSI supports the advancement of sustainable, risk-aware, and technically optimized blasting practices within modern quarry operations. Full article

Particulate Matter (PM) is a type of air pollution that poses risks to human health, the environment, and property. Among the various PM types, PM₁₀ is particularly significant, as it acts as a vector for numerous hazardous trace elements that can negatively impact human health and the ecosystem. Identifying potential sources of PM₁₀ and quantifying their impact on ambient concentrations is crucial for developing efficient control strategies to meet threshold values. Receptor modeling, which identifies sources using chemical species information derived from PM samples, has been widely used for source apportionment. In this study, PM₁₀ samples were collected over three periods (April, May, and June 2021), each lasting 16 days, using semi-automatic dust sampling systems at two sites in Biga, Canakkale, Turkiye. The relative contributions of different source types were quantified using EPA PMF (Positive Matrix Factorization) based on 35 elements comprising PM₁₀. As a result of the analysis, five source types were identified: crustal elements/limestone/calcite quarry (64.9%), coal-fired power plants (11.2%), metal industry (9%), sea salt and ship emissions (8.5%), and road traffic emissions and road dust (6.3%). The distribution of source contributions aligned with the locations of identified sources in the region. Full article

The development of sustainable self-compacting concrete (SCC) requires alternative binders that minimise ordinary Portland cement (OPC) consumption while ensuring long-term performance. This study investigates sulfate-activated SCC (SA SCC) incorporating high volumes of industrial by-products, whereby 72% ground granulated blast furnace slag (GGBS) and 18% fly ash (FA) were activated with varying proportions of OPC and gypsum. Quarry dust was used as a fine aggregate, while granite and electric arc furnace (EAF) slag served as coarse aggregates. Among all formulations, the binder containing 72% GGBS, 18% FA, 4% OPC, and 6% gypsum was identified as the optimum composition, providing superior mechanical performance across all curing durations. This mix achieved slump flow within the EFNARC SF2 class (700–725 mm), compressive strength exceeding 50 MPa at 270 days, and flexural strength up to 20% higher than OPC SCC. Drying shrinkage values remained below Eurocode 2 and ASTM C157 limits, while EAF slag increased density, but slightly worsened shrinkage compared to granite mixes. Microstructural analysis (SEM-EDX) confirmed that strength development was governed by discrete C-S-H and C-A-S-H gels surrounding unreacted binder particles, forming a dense interlocked matrix. The results demonstrate that sulfate activation with a 4% OPC + 6% gypsum blend enables the production of high-performance SCC with 94–98% industrial by-products, reducing OPC dependency and environmental impact. This work offers a practical pathway for low-carbon SCC. Full article

This paper presents a real-time quarry truck monitoring system that combines deep learning and license plate recognition (LPR) for operational monitoring and weighbridge reconciliation. Rather than estimating load volumes directly from imagery, the system ensures auditable matching between detected trucks and official weight records. Deployed at quarry checkpoints, fixed cameras stream to an edge stack that performs truck detection, line-crossing counts, and per-frame plate Optical Character Recognition (OCR); a temporal voting and format-constrained post-processing step consolidates plate strings for registry matching. The system exposes a dashboard with auditable session bundles (model/version hashes, Region of Interest (ROI)/line geometry, thresholds, logs) to ensure replay and traceability between offline evaluation and live operations. We evaluate detection (precision, recall, mAP@0.5, and mAP@0.5:0.95), tracking (ID metrics), and (LPR) usability, and we quantify operational validity by reconciling estimated shift-level tonnage T against weighbridge tonnage T* using Mean Absolute Error (MAE), Mean Absolute Percentage Error (MAPE), R², and Bland–Altman analysis. Results show stable convergence of the detection models, reliable plate usability under varied optics (day, dusk, night, and dust), low-latency processing suitable for commodity hardware, and close agreement with weighbridge references at the shift level. The study demonstrates that vision-based counting coupled with plate linkage can provide regulator-ready KPIs and auditable evidence for production control in quarry operations. Full article

Sandstone quarrying in Lekokoaneng contributes to both local and national economic development, yet it raises concerns about environmental degradation and community livelihoods. Using a mixed-methods design framed by the Sustainable Livelihood Framework (SLF) and the Sustainable Development Theory (SDT), 203 households were surveyed across five buffer zones (0–1000 m) around the formal quarry site in Lekokoaneng, Berea District, Lesotho. Quantitative data were analysed descriptively, while qualitative responses underwent thematic analysis and were transformed into quantifiable categories. Quarrying generated employment and small-business opportunities concentrated within 0–600 m of the site, alongside elevated reports of dust, soil degradation and water contamination that undermined agriculture and health. Households nearest the quarry reported the highest income benefits (e.g., 35% via employment) but also the greatest environmental burdens. Households furthest away reported fewer risks but also limited economic gain. Thematic analysis yielded four domains: Socio-Economic Empowerment, Livelihood Vulnerability, Health and Safety Risks, and Environmental Degradation and Control. Integrating SLF and SDT shows quarrying as a double-edged livelihood system with short-term financial gains that coincide with erosion of natural, human and social capitals. Targeted environmental safeguards, labour formalisation and community-inclusive governance are essential to realign quarrying with resilience and sustainability goals. Full article

Road and pavement construction require huge volumes of borrowed soils in addition to the foundation soils. Unfortunately, not all soils are suitable for construction purposes. Soil stabilization is a fundamental technique used to enhance the engineering properties of weak ground/soil to meet the demands of large infrastructure projects, such as roads. It is in this regard that this study investigates the strength development, durability, and effectiveness of cement and quarry dust as stabilizers to enhance the geotechnical properties of a weak tropical clay soil. Cement was added in the range of 0% to 10% while quarry dust was used to partially replace soil in the range of 0% to 50%. The results show significant improvements in the Atterberg limits and strength properties of the tropical clay. The liquid limit reduced from 43.2% to 25.1% while the plasticity index reduced from 17.6% to 10.2% at 50% quarry dust and 10% cement content. Similarly, the maximum dry unit weight increased from 17.4 kN/m³ to 21.3 kN/m³ while the optimum moisture content decreased from 17.1% to 12.9%. The maximum soaked CBR value was 172%, representing a 1497% enhancement over untreated soil. Also, the maximum unconfined compressive strength (UCS) reached 2566 kN/m² at 28 days of curing, representing a 1793.73% increase when compared to the untreated soil. Cement content was found to be the predominant factor influencing strength development. The study shows that cement–quarry dust blends compacted at high energy can be adopted in sustainable road construction. Full article

Quarry dust (QD) landfill causes environmental issues that cannot be ignored. In this study, we systematically explore its potential application as a supplementary cementitious material (SCM) in cemented paste backfill (CPB), revealing the activated mechanism of modified QD (MQD) and exploring the hydration process and workability of CPB containing QD/MQD. The experimental results show that quartz, clinochlore and amphibole components react with CaO to form reactive dicalcium silicate (C₂S) and amorphous glass phases, promoting pozzolanic reactivity in MQD. QD promotes early aluminocarbonate (M_c) formation through CaCO₃-derived CO₃²⁻ release but shifts to hemicarboaluminate (H_c) dominance at 28 d. MQD releases active Al³⁺/Si⁴⁺ due to calcination and deconstruction, significantly increasing the amount of ettringite (AFt) in the later stage. With the synergistic effect of coarse–fine particle gradation, MQD-type fresh backfill can achieve a 161 mm flow spread at 20% replacement. Even if this replacement rate reaches 50%, a strength of 19.87 MPa can still be maintained for 28 days. The good workability and low carbon footprint of MQD-type backfill provide theoretical support for—and technical paths toward—QD recycling and the development of low-carbon building materials. Full article

Concrete and mortar production consumes significant natural resources, leading to environmental concerns and sustainability challenges. Sustainable alternatives, such as industrial byproducts, have been explored to replace clinkers and aggregates. Basalt rock powder (BRP) is a promising option due to its physical and chemical properties, including its better particle size distribution and compatibility with cementitious composites, and studies have highlighted its pozzolanic activity and its potential to improve mechanical properties (compressive strength, flexural strength, and durability). Reusing rock dust as a raw material could transform it into a mineral byproduct, benefiting the new material and reducing waste volumes. This article presents a systematic literature review on the use of BRP in construction materials, conducted using the Scopus, ScienceDirect, PubMed, and Web of Science databases and following the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) procedures. The search resulted in 787 articles (up to December 2024) and, after the screening process, 17 met the inclusion criteria. From the selected articles, information regarding the utilization of this waste product; its influence on mechanical properties, pozzolanic activity, and durability; and the sustainability associated with its use was compiled. The risk of bias was low as the search was comprehensive, all the papers were peer-reviewed, and all authors reviewed the papers independently. In conclusion, the studies demonstrate the potential of using BRP as a component of cementitious materials, indicating it as a possible innovative solution to the current challenges in the construction industry. Full article

This study presents the geotechnical evaluation of phosphogypsum, a byproduct of phosphate fertilizer production. The objective is to assess the suitability of phosphogypsum or its mixtures with natural materials as a technically viable and environmentally responsible backfill material for the restoration of closed and abandoned quarries. This study adds to the scarce existing literature on the use of phosphogypsum for quarry reclamation and further investigates the behavior of phosphogypsum mixtures incorporating clay and marble dust. A comprehensive experimental program was conducted to evaluate typical geotechnical properties, i.e., grain size distribution, Atterberg limits, compaction characteristics, permeability, compressibility, and shear strength. The results indicate that phosphogypsum is fine grained, low in plasticity, and exhibits relatively high permeability and compressibility, which limits its application as a deep fill material. The addition of clay increased the liquid and plastic limits but had a limited positive effect on strength and compressibility. In contrast, mixtures with marble dust improved particle gradation, reduced permeability, and enhanced compaction behavior without significantly increasing plasticity or settlements. Notably, the most promising mixture of phosphogypsum with a modest proportion of marble dust demonstrates improved shear strength and reduced hydraulic conductivity, making it suitable for use in the upper layers of quarry fills. Full article

PM₁₀ emissions have been a significant concern in rock crushing and quarry operations (study site #1) and iron ore mining projects (study site #2) in certain regions of Malaysia, posing fears to the health and well-being of nearby communities with severe air pollution. To address this issue, it is crucial to develop effective mitigation strategies to reduce dust particle emissions like PM₁₀ in the ambient air. The AERMOD model was applied to predict PM₁₀ emissions during quarry operations and iron ore mining projects, both with and without control measures. The results indicated that PM₁₀ emissions were reduced when control measures were implemented. The modeling result shows the mean PM₁₀ concentration with and without control measures in study site #1 is 74.85 µg/m³ and 20,557.69 µg/m³, respectively. In comparison, the average PM₁₀ concentration with and without control measures in study site #2 is 53.95 µg/m³ and 135.69 µg/m³. Therefore, the control measure has successfully reduced the PM₁₀ concentrations by 99.90% and 60.24% in study sites #1 and #2, respectively, and ensures the air quality complies with the Malaysian Ambient Air Quality Guidelines (MAAQG) 24 h threshold limits at 100 µg/m³. In addition, the AERMOD modeling results showed that mitigation measures performed better in rock crushing and quarry operations than in iron ore mining projects in this case study. Full article

The presented paper analyzes the impact of limestone dust accumulation on photovoltaic (PV) panel performance, focusing on the specific surrounding conditions near quarries. The results from the performed field measurements show that high concentrations of limestone dust accumulate significantly faster in these areas, and a hard layer is formed in the presence of moisture. This layer of dust is resistant to removal, even in moderate precipitation and winds with speeds between 6 and 9 m/s, making it a significant problem for the long-term performance of the systems. The analysis revealed that the lack of systematic cleaning of the panels leads to a drop in efficiency of over 20%, with this loss pointedly limiting the return on investment. This study highlights the need for innovative maintenance approaches, such as regular cleaning, use of special coatings and adapting designs to specific environmental conditions. This is essential for the development of strategies to manage, maintain and improve PV systems in areas with high levels of dust pollution. Full article