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The dry beach length determines the hydraulic boundary of tailings impoundments and significantly impacts the infiltration line, which is crucial for the tailings dam. A deep learning method utilizing satellite images is presented to recognize the dry beach area and accurately measure the length of dry beaches in tailing ponds. Firstly, satellite images of various tailing ponds were gathered and the collection was enlarged to create a dataset of satellite images of tailing ponds. Then, a deep learning method was created using YOLOv5-seg to identify the dry beach area of tailing ponds from satellite images. The mask of the dry beach region was segmented and contour extraction was then carried out. Finally, the beach crest line was fitted based on the extracted contour. The pixel distance between the beach crest line and the dry beach boundary was measured and then translated into real distance by ground resolution. This paper's case study compared the calculated length of dry beach with the real length obtained by field monitoring. The results of the case study showed that the minimum error of the method was 2.10%, the maximum error was 3.46%, and the average error was 2.70%, indicating high precision for calculating dry beach length in tailing ponds. [ABSTRACT FROM AUTHOR]

There has been a frequent occurrence of tailing dam failures in recent years, leading to severe repercussions. Flood overtopping is an important element contributing to these failures. Nevertheless, there is a scarcity of studies about the evolutionary mechanisms of dam breaches resulting from flood overtopping. In order to fill this knowledge vacuum, this study focused on the evolutionary characteristics and triggering mechanisms of overtopping failures, utilizing the Heshangyu tailings pond as a prototype. The process of overtopping breach evolution was revealed by the conduction of small-scale model testing. A scaled-down replica of the tailings pond was constructed at a ratio of 1:150, and a controlled experiment was conducted to simulate a breach in the dam caused by water overflowing. Based on the results, the following conclusions were drawn: (1) The rise in water level in the pond caused the tailings to become saturated, leading to liquefaction flow and local slope sliding at the initial dam. If the sediment-carrying capacity of the overflowing water exceeded the shear strength of the tailings, water erosion would accelerate landslides on the slope, generating a sand-laden water flow. (2) The breach was primarily influenced by water erosion, which subsequently resulted in both laterally widened and longitudinally deepened breach. As the breach expanded, the sand-carrying capacity of the water flow increased, leading to a faster rate of failure. The breach process of overtopping can be categorized into four distinct stages: gully formation stage, lateral broadening stage of gully, cracks and collapse on the slope surface, and stable stage of collapse. (3) The tailings from the outflow spread downstream in a radial pattern, forming an alluvial fan. Additionally, the depth of the deposited mud first increased and subsequently declined as the distance from the breach grew. The findings of this research provide an important basis for the prevention and control of tailings dam breach disasters due to overtopping. [ABSTRACT FROM AUTHOR]

Tailings ponds are recognized as significant sources of potential man-made debris flow and major environmental disasters. Recent frequent tailings dam failures and growing trends in fine tailings outputs underscore the critical need for innovative monitoring and safety management techniques. Here, we propose an approach that integrates UAV photogrammetry with convolutional neural networks (CNNs) to extract beach line indicators (BLIs) and conduct enhanced dam safety evaluations. The significance of real 3D geometry construction in numerical analysis is investigated. The results demonstrate that the optimized You Only Look At CoefficienTs (YOLACT) model outperforms in recognizing the beach boundary line, achieving a mean Intersection over Union (mIoU) of 72.63% and a mean Pixel Accuracy (mPA) of 76.2%. This approach shows promise for future integration with autonomously charging UAVs, enabling comprehensive coverage and automated monitoring of BLIs. Additionally, the anti-slide and seepage stability evaluations are impacted by the geometry shape and water condition configuration. The proposed approach provides more conservative seepage calculations, suggesting that simplified 2D modeling may underestimate tailings dam stability, potentially affecting dam designs and regulatory decisions. Multiple numerical methods are suggested for cross-validation. This approach is crucial for balancing safety regulations with economic feasibility, helping to prevent excessive and unsustainable burdens on enterprises and advancing towards the goal of zero harm to people and the environment in tailings management. [ABSTRACT FROM AUTHOR]

This paper presents the results of a selective flocculation/magnetic separation study performed with a sample of iron ore slime from the desliming stage of the industrial flotation circuit of a mine in the southern region in the Quadrilátero Ferrífero-Brazil that was discarded in a tailings dam. Zeta potential measurements of pure minerals previously identified in the sample (goethite = 52.4%, hematite = 26.2%, quartz = 12.3%, kaolinite = 8.2%, and others = 0. 9%) were evaluated to assess the influence of the reagents used (sodium hexametaphosphate – SHMP (dispersant)) and flocculants (corn starch, nonionic polyacrylamide – P2500 and cationic polyacrylamide – P806)) on their surface properties and consequently on the stability of suspensions of the slime and of the pure minerals individually, aiming to establish conditions for selective separation between Fe-bearing minerals (goethite and hematite) and gangue minerals (quartz and kaolinite) in the subsequent magnetic separation step. At pH 10 and a 25 mg/L dosage of SHMP, a higher Fe recovery was verified with starch (2000 g/t) in relation to nonionic and cationic polyacrylamides, and similar Fe contents in all dosages tested of the flocculants. [ABSTRACT FROM AUTHOR]

In this paper, ground deformation measurements from synthetic aperture radar interferometry (InSAR) and ground-based prism monitoring are compared to finite-element (FE) simulation results for a recent tailings dam collapse. The InSAR monitoring demonstrated the complex spatial and temporal variability of the tailings dam deformation that is not captured in traditional, point-based monitoring approaches. Potentially anomalous deformation behaviour could have been detected from InSAR 1 year preceding the dam failure. A two-dimensional coupled-consolidation analysis was used to predict the dam behaviour during construction stages. The FE modelling results were in broad agreement with the deformation measurement sources, both in terms of magnitude and trends preceding failure. The results, however, deviate significantly immediately before failure, following the construction of the buttresses. Moreover, the FE modelling is sensitive to parameter uncertainties, such as spatial variability of foundation soil properties. The FE results revealed that deformation in both the upstream and downstream parts of the dam are sensitive to changing foundation properties. However, this impact is potentially much more significant on the downstream compared to the upstream parts of the dam, which are dominated by the behaviour of the tailings. This study highlights the efficacy and complementarity of geotechnical and remote sensing techniques for the monitoring of tailings dams. [ABSTRACT FROM AUTHOR]

Major tailings dam failures have occurred recently around the world and resulted in severe environmental impacts, such as metal contamination. Manganese is a metal highly associated with mining activities, largely detected in mining dam collapses. This metal is considered necessary for different organisms, but it can be toxic and cause oxidative stress and genetic damage in fishes. In this study, we investigated the toxic effects of manganese on Astyanax lacustris, by exposing the fish individually to different concentrations of this metal (2.11, 5.00, and 10.43 mg/L) for 96 h. To assess the effects of manganese, we used biochemical biomarkers (glutathione S-transferase, catalase, and acetylcholinesterase enzyme activity) and the manganese bioaccumulation in different tissues (liver and gills). The obtained data showed that only at concentrations of 5.00 mg/L and 10.43 mg/L the activity of glutathione S-transferase differed significantly. Additionally, the acetylcholinesterase activity in the brain tissue was inhibited. The highest level of manganese bioaccumulation was observed in the liver and branchial tissue. Overall, we concluded that high concentrations of manganese may cause physiological changes in Astyanax lacustris. [ABSTRACT FROM AUTHOR]

Potentially harmful element (PHE) bioavailability is important to environmental contamination and must be checked under several soil conditions. This study aimed to assess Fe, Mn, and PHE uptake by rice (Oryza sativa) grown on flooded and non-flooded Fe tailings collected from the Doce River basin after its collapse in Brazil. After 65 days of sowing, shoots and roots were harvested to determine PHE concentrations. The mean concentrations of Mn in shoots and Fe in the roots of rice grown on the flooded tailings were 2140 mg kg−1 and 15,219 mg kg−1, respectively. Mn was extensively translocated from roots to shoots (translocation factor (TF) = 2). Conversely, Fe accumulated in roots (TF = 0.015) and caused morphological damage to this rice organ. The application of macro and micronutrients lessened Fe toxicity in the roots of rice cultivated on the flooded tailings. The flooding of tailings influenced more Fe accumulation than Mn accumulation by rice plants. The PHE Ag, As, Cd, Ni, Hg, Pb, and Sb exhibited low total concentrations (maximum of 9 mg kg−1 for Ni and a minimum of 0.2 mg kg−1 for Cd, Hg, and Sb), and it was not observed an increase in their availability under tailings flooding conditions. [ABSTRACT FROM AUTHOR]

The presence of lenses such as tailings slurry, frozen soil, and saturated zones disrupts the continuity of tailings dams and their normal seepage patterns, elevating the seepage line of the dam body and significantly impacting local stability. This study, to investigate how lenses affect the stability and failure mechanisms of tailings dams, employs numerical simulation and physical models and constructs a model of the tailings dam, incorporating tailings clay lens and void lens, to investigate variations in hydraulic gradients, seepage velocities, seepage flow, pore water pressure, and the patterns of seepage failure. This research reveals that the tailings clay lens within the dam body increases the hydraulic gradient in its vicinity due to its low permeability and raises the phreatic line. As the tailings clay lens approaches the dam body, the phreatic line tends to escape along the upper part of the lens towards the dam surface. In addition, the void lens could lead to a more pronounced seepage gradient along its path on the dam surface, with a liquefaction beneath it. As the void lens nears the toe of the slope, the dam failure mode transitions from a step-like progressive failure to an arch-shaped settlement failure along the void lens. [ABSTRACT FROM AUTHOR]

Stability analyses of tailings dams often utilize advanced constitutive models that require the calibration of many parameters. Yet, there remains limited research on the implications of parameter uncertainties within these constitutive models on the safety factor of tailings dams. This study successfully investigated the impact of uncertainty in critical state parameters of the NorSand model on the stability of a tailings dam. To achieve this goal, field and laboratory tests characterized the materials constituting the geotechnical profile of the dam, involving residual shale soils, alluvial soils, and granular-textured tailings. These tests were included in the finite element (FE) program PLAXIS 2D to estimate several parameters of the constitutive models that characterized the materials of the dam: Hardening Soil, Mohr–Coulomb, and NorSand. Monte Carlo simulations of FE analyses were conducted considering the construction period of the dam spanning 2500 days. Furthermore, the critical state line (CSL) parameters employed within the NorSand model were reconciled with void ratio data for the uncompacted tailings utilizing a Bayesian framework. The Bayesian framework allowed us to investigate: (i) the statistical distribution of the critical state parameters, (ii) confidence intervals for horizontal and vertical displacements, (iii) shear strains at various monitoring points across the tailings dam, (iv) and the marginal distribution of the factor of safety. The findings reveal a strong correlation between the three CSL parameters, which presented poorly defined statistical distributions. Nonetheless, the power law equation used to model the CSL closely matches laboratory data from triaxial tests (R2 = 0.97). Uncertainties in the CSL, especially at lower stress levels, contribute to settlement prediction uncertainties. Monitoring points at the structure's base showed strains that could induce downstream slope instability and potential liquefaction failure. The histogram of the safety factors remained narrow, normally distributed, ranging from 1.39 to 1.47. This work is important because it explicitly addresses the uncertainty in the critical state parameters of the NorSand model within geotechnical analysis. [ABSTRACT FROM AUTHOR]

In the last decade, Brazil witnessed disasters relating to tailings dams. This led to changes in the National Dam Safety Policy, which regulates a set of measures to improve dam safety management. In this context, this paper presents a case study of the Ribeirão João Leite dam. The dam consists of a concrete gravity structure with embankment fill at both abutments, placed on a foundation composed of gneiss with quartzite veins. The study aims to investigate its seepage behavior and assess the performance of the seepage control system in the concrete and embankment cross-sections at the right abutment. Two-dimensional seepage analyses under steady-state and transient conditions were performed using the finite element method. A straightforward approach based on monitoring data was proposed to validate seepage analyses and estimate the efficiency of the seepage control system. It was concluded that the foundation of the dam has a significant influence on the pore water pressures and seepage flow behavior due to the presence of markedly fractured materials. The analyses indicated that the efficiency of the grout curtain in the right abutment foundation is not noticeable. On the other hand, the foundation drains play an important role in controlling pore water pressures throughout the dam foundation, even in unfavorable geological conditions. The efficiency of these drains was 28% at the drainage line of Block 2, preventing pressure increases of 36% in the foundation of Block 2 and 160% in the horizontal filter drain. [ABSTRACT FROM AUTHOR]

The instability of earth structures resting on granular materials, such as embankments and tailing dams, is caused by the infiltration of water which can lead to their failure. This paper presents the potential use of tyre crumbs (TCr) for controlling the onset of instability of sand. Constant shear-drained experiments were carried out on mixtures of sand and TCr to understand the onset of instability. Conventional drained shear tests were carried out on all samples up to a deviator stress of 200 kPa. The CSD tests were then carried out on the sheared samples by reducing the confining pressure until the onset of instability. The onset of instability was determined by a drop in stress, by second-order work and by the strain ratio approach. The value of mean effective stress at the onset of instability was found to decrease with the addition of TCr to the mix of up to 20% and then increase with further addition of TCr. The strain ratio approach was found to predict the onset of instability easily and efficiently, similar to the second-order work method. [ABSTRACT FROM AUTHOR]

Slope failures possess destructive power that can cause significant damage to both life and infrastructure. Monitoring slopes prone to instabilities is therefore critical in mitigating the risk posed by their failure. The purpose of slope monitoring is to detect precursory signs of stability issues, such as changes in the rate of displacement with which a slope is deforming. This information can then be used to predict the timing or probability of an imminent failure in order to provide an early warning. Most approaches to predicting slope failures, such as the inverse velocity method, focus on predicting the timing of a potential failure. However, such approaches are deterministic and require some subjective analysis of displacement monitoring data to generate reliable timing predictions. In this study, a more objective, probabilistic-learning algorithm is proposed to detect and characterise the risk of a slope failure, based on spectral analysis of serially correlated displacement time-series data. The algorithm is applied to satellite-based interferometric synthetic radar (InSAR) displacement time-series data to retrospectively analyse the risk of the 2019 Brumadinho tailings dam collapse in Brazil. Two potential risk milestones are identified and signs of a definitive but emergent risk (27 February 2018-26 August 2018) and imminent risk of collapse of the tailings dam (27 June 2018-24 December 2018) are detected by the algorithm as the empirical points of inflection and maximum on a risk trajectory, respectively. Importantly, this precursory indication of risk of failure is detected as early as at least five months prior to the dam collapse on 25 January 2019. The results of this study demonstrate that the combination of spectral methods and second order statistical properties of InSAR displacement time-series data can reveal signs of a transition into an unstable deformation regime, and that this algorithm can provide sufficient early-warning that could help mitigate catastrophic slope failures. [ABSTRACT FROM AUTHOR]

Purpose: The Buenavista del Cobre mine is in a semiarid environment in NW Mexico. A part of the mine tailings dam has been flooded with wastewater from Cananea, generating an artificial wetland. The main objectives of this work were to evaluate the effect of wastewater on the pedogenesis of wetland Technosols developed on mine tailings and to compare them with the soil of non-irrigated tailings and with a natural soil profile. Materials and methods: Three profiles were studied inside the dam as follows: a profile under waterlogging conditions, a profile under conditions of periodic sewage saturation, and a profile with no waterlogging conditions. Laboratory methods included the micromorphological analysis of the soil structure and pedo-features, fertility properties, identification of clay minerals, and analysis of bulk chemical composition. Results and discussion: It was found that the biogenic structure and voids associated with organic materials were the main micromorphological features of the studied wetland Technosols. Primary sulfides remained unaltered in the Technosols irrigated with wastewater, whereas incipient sulfide oxidation was observed in the non-irrigated tailings. Chlorite and smectite were detected in the Technosols. Such mineral assemblage was found to be mostly generated by hydrothermal processes. Conclusion: Irrigation of tailings with wastewater supported the biological aggregation and porosity formation within the soil matrix, supplied plant nutrients, and enhanced the ecological soil quality of the studied hydromorphic Technosols. Saturation with wastewater hampered the oxidation of primary sulfides in the hydromorphic Technosols, preventing soil acidification and the mobilization of heavy metal contaminants. [ABSTRACT FROM AUTHOR]

Tailings are a significant concern due to their potential release of toxic elements into the environment, posing risks to ecosystems and human health. Therefore, understanding their polluting potential is crucial for effective mitigation strategies. This study evaluates the contaminating potential of eight tailing dams in the upper basin of the Puyango River in southern Ecuador. A physicochemical and mineralogical characterization of the tailings was conducted. The contents of As, Cd, Co, Cr, Cu, Mo, Ni, Pb, Sb, Se, V, and Zn were determined using Inductively Coupled Plasma Mass Spectrometry (ICP-MS) and Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES). The contamination index (IC) and the risk (RI) to the environment and population were evaluated. As a result, it was found that As, Cu, Pb, Se, and Zn exceeded the maximum permissible limits in all the samples according to Ecuadorian regulations. Six of the eight tailing dams presented very high pollution levels (21.28 < IC < 298.61), indicating a severe contamination risk. As, Sb, and Se were the most significant contributors to the index, with 29%, 31%, and 20% contribution to the overall IC, respectively. However, the risk assessment indicated a low risk (RI < 5) to both the population and the natural environment, mainly due to the distance between the tailing dams and the potential receptors. While the present risk associated with the studied tailing dams is low, there exists potential for long-term escalation. [ABSTRACT FROM AUTHOR]

Sulfur oxidizing bacteria (SOB) play a key role in sulfur cycling in mine tailings impoundment (TI) waters, where sulfur concentrations are typically high. However, our understanding of SOB sulfur cycling via potential S oxidation pathways (sox, rdsr, and S4I) in these globally ubiquitous contexts, remains limited. Here, we identified TI water column SOB community composition, metagenomics derived metabolic repertoires, physicochemistry, and aqueous sulfur concentration and speciation in four Canadian base metal mine, circumneutral-alkaline TIs over four years (2016 - 2019). Identification and examination of genomes from nine SOB genera occurring in these TI waters revealed two pH partitioned, metabolically distinct groups, which differentially influenced acid generation and sulfur speciation. Complete sox (csox) dominant SOB (e.g., Halothiobacillus spp., Thiomonas spp.) drove acidity generation and S2O32- consumption via the csox pathway at lower pH (pH ~5 to ~6.5). At circumneutral pH conditions (pH ~6.5 to ~8.5), the presence of non-csox dominant SOB (hosting the incomplete sox, rdsr, and/or other S oxidation reactions; e.g. Thiobacillus spp., Sulfuriferula spp.) were associated with higher [S2O32-] and limited acidity generation. The S4I pathway part 1 (tsdA; S2O32- to S4O62-), was not constrained by pH, while S4I pathway part 2 (S4O62- disproportionation via tetH) was limited to Thiobacillus spp. and thus circumneutral pH values. Comparative analysis of low, natural (e.g., hydrothermal vents and sulfur hot springs) and high (e.g., Zn, Cu, Pb/Zn, and Ni tailings) sulfur systems literature data with these TI results, reveals a distinct TI SOB mining microbiome, characterized by elevated abundances of csox dominant SOB, likely sustained by continuous replenishment of sulfur species through tailings or mining impacted water additions. Our results indicate that under the primarily oxic conditions in these systems, S2O32- availability plays a key role in determining the dominant sulfur oxidation pathways and associated geochemical and physicochemical outcomes, highlighting the potential for biological management of mining impacted waters via pH and [S2O32-] manipulation. [ABSTRACT FROM AUTHOR]

Copyright of Nonferrous Metals Engineering is the property of Beijing Research Institute of Mining & Metallurgy Technology Group and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Depending on the ore quality, a washing process can be conducted with the bauxite, which basically consists of scrubbing the ore and screening in order to increase the available alumina grade, i.e., the alumina extractable using the Bayer Process, and reduce the impurity content. Tailings are usually disposed of in a tailings dam in the form of a slurry, which is a mixture of solid particles and liquid, consisting mainly of ultra-fine kaolinite, making the dewatering operation challenging. To reduce the environmental impact, mining companies are studying alternative methods to dewater the tailings, and different dewatering methods are available worldwide. The use of new technologies to dewater the tailings has contributed to facing the challenges of achieving sustainable development with their disposal. The decanter centrifuges are already an option for operations for the Canadian oil sands, gold ore in Peru, and nickel in New Caledonia; they are also being tested for iron ore in Brazil. In the present work, bauxite dewatering using the decanter centrifuge was evaluated to understand more about the behavior of these materials and to investigate the effects of various process parameters on the solid recovery and solid content of the flows, using three different kinds of equipment. The results indicated that decanter centrifuges can be used to achieve a high concentration of solids in the cake, with values ranging from 60% to 80% solids per weight and a great clarification in the liquid phase (centrate) from 0 to 6% solids per weight, values which mean the solid phase is suitable for reutilization in the processing circuit. Additionally, the present work provides a better understanding of how different solid contents feed can affect the behavior of the equipment. [ABSTRACT FROM AUTHOR]

The design of tailings dams has improved significantly in recent decades due to experience and advances in applied research. However, there are still several environmental and geomechanical uncertainties associated with the response of these structures. Failures on the wall of tailings dams are well documented, where the most common causes are related to the action of water overtopping, slope instability, seepage, and foundation failure. Measuring the humidity or the saturation level at tailings dam walls has become a must do in the recent years. Resistivity monitoring using electrical resistivity tomography (ERT) techniques has proven to be one of the tools that provide good subsurface characterization for internal erosion detection and seepage assessment to evaluate potential environmental risks and the physical stability of tailings dams. Also, the integrated techniques of geotechnical, geophysical, and geochemical data have been used to correlate, coordinate, and improve the characterization. In this research, a procedure to guide us to a new methodology of acquiring and monitoring humidity content is presented, in which 2D electrical resistivity tomography (ERT) profiles are linked to the degree of soil saturation, using moisture sensors installed in a nearby well. The ERT profiles provide a 2D resistivity profile, and the moisture sensors can measure resistivity and volumetric water content (VWC) at a given installation depth. This second measure (VWC), with a defined total porosity, can be combined with Archie's empirical law to obtain the degree of saturation, allowing the possibility to create remote monitoring suitable for mining operations without excessive laboratory testing. [ABSTRACT FROM AUTHOR]

One of the critical challenges facing the mining sector is related to the prevention and mitigation of catastrophic incidents associated with its tailing dams. As mining tailings are very heterogeneous and field characterization is expensive and complex, geotechnical properties of these materials are largely unknown. The seismic cone penetration test (SCPTu) provides a field approach to estimate a large array of geotechnical information, including the liquefaction potential of tailing dams. Yet, the exploration of strain softening behaviors in geomaterials under undrained loading, utilizing the state parameter ( ψ ) inferred from SCPTu tests initially applied to soft soils, has been often used for mining tailings. This study is concerned with the implementation of a tailing classification system which uses the ratio between the small strain shear modulus and the cone tip resistance ( G 0 / q t ). A series of laboratory tests was executed, and three different methodologies were adopted to assess the effects of (partial) drainage conditions based on 531.26 m of SCPTu measurements conducted at three different upstream iron ore tailing dams in Brazil. Furthermore, the G 0 / q t ratio is integrated with ψ to assess the liquefaction tendencies of the investigated materials. The findings reveal the heterogeneous nature of the tailings, wherein indications of partial drainage are discernible across numerous records. Liquefaction analyses demonstrate that the tailings exhibit a contractive behavior in over 94% of the SCPTu data, confirming their susceptibility to flow liquefaction. Our findings are relevant for site characterization within iron ore tailing dams and other mining sites with similar geotechnical attributes. [ABSTRACT FROM AUTHOR]

Copyright of Revista Foco (Interdisciplinary Studies Journal) is the property of Revista Foco and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Dyna is the property of Universidad Nacional de Colombia, Medellin, Facultad de Minas and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Tailings disposal is a major concern of the mining industry worldwide. After the recent upstream dam failures, the main tailings disposal method studied in Brazil is dry stacking. The mechanical behaviour of tailings disposed of by dry stacking can be enhanced by ground improvement techniques such as compaction effort, cement, and fibre insertion. Accordingly, the study was carried out herein to analyse the mechanical behaviour of a fibre-reinforced cemented iron ore tailings (IOT) through unconfined compression tests in specimens moulded at different points on the compaction curve using 1%, 3% and 5% of Portland cement and zero and 0.5% of polypropylene fibres as an alternative to enhance the overall performance of dry tailings storage facilities. The results showed that compacted fibre-reinforced cemented IOT strength and stiffness vary according to the dry unit weight and moisture content moulding point on the standard Proctor compaction curve. In addition, adding fibres to the compacted cemented IOT turns the brittle behaviour into a ductile one, especially for 1% of cement. Such enhancement is fundamental to guarantee the safety of iron dry stacks. Also, failure patterns are directly related to the moulding point on the compaction curve. Moreover, adding fibres has increased the strength of cemented and uncemented IOT, thus allowing the adoption of smaller cement contents. Therefore, for the first time, the behaviour of fibre-reinforced cemented IOT was presented and its dependency on moulding characteristics based on compaction curves position. [ABSTRACT FROM AUTHOR]

Explicitly modelling tailings consolidation behaviour contributes to improve integrated management approaches and accurately estimate the storage capacity of tailings storage facilities (TSFs) to better predict their static and dynamic stability. However, slurry tailings demonstrate a highly non-linear evolution of stiffness and hydraulic conductivity during consolidation, thus significantly complexifying the determination of their hydromechanical properties. In this study, an approach to update Mohr Coulomb parameters and simulate the continuous evolution of hydraulic conductivity and stiffness of tailings materials with the reduction of the void ratio was proposed and embedded in a finite difference code to more realistically simulate the evolution of material properties during sequential loadings. The model was validated using laboratory column tests and various predictive functions were tested to estimate hydraulic conductivity for field applications. Finally, the developed approach was applied to a simplified model of tailings impoundment to illustrate practical applications. Results from this study indicated that the approach developed was able to capture the non-linearity properties of tailings during consolidation, and that using continuously updated stiffness and hydraulic conductivity could induce significantly different magnitude and rate of consolidation than models with constant properties. Predictive models such as Kozeny–Carman and Kozeny–Carman Modified models also gave a satisfactory estimation of tailings behaviour, at least for preliminary studies. The simple modifications to the numerical codes proposed in this paper could therefore significantly improve the numerical simulation of tailings behaviour in the short term and contribute to a better planning of deposition plans. [ABSTRACT FROM AUTHOR]

The design of retaining dikes for tailings deposited hydraulically in surface impoundments raises various geotechnical issues, including the risk of instability along the external slope. Coarse grained waste rock produced at the mine can be placed within the impoundment to create stiff and draining inclusions that greatly improve stability by accelerating consolidation and providing reinforcement. This paper presents results from stability analyses conducted to assess the effect of WRI on the static stability of reinforced tailings impoundments with progressively raised upstream dikes, considering different geometries and loading conditions. Emphasis of these analyses is placed on effective stress calculations that take into account the generation and dissipation of excess porewater pressures induced by sequential deposition of tailings layers, which leads to transient increases of the excess porewater pressures and reduction of the factor of safety. The stability calculations results, obtained from a combination of transient finite element and limit equilibrium analyses, show the positive influence of adding WRI on critical short term response, and illustrate how such inclusions can be used to enhance the stability of retaining dikes. [ABSTRACT FROM AUTHOR]

Scientific calculating of deformation early warning thresholds is of great significance for identifying the abnormal operation state of tailings dams. Traditional early warning studies cannot take into account the fuzziness and randomness of monitoring data, and most of them focus on single-point and single-level early warning, which cannot accurately reflect the operational state and the risk level of failure of the tailings dam. In this study, an early warning model based on cloud theory (CT) and concept hierarchy construction (CHC) is proposed to determine a reliable warning of multi-point displacement of tailings dam. The CT is used to calculate the characteristic values of displacements, including expectation (Ex), entropy (En), and hyper entropy (He), which can eliminate the influence of fuzziness and randomness of the monitoring data. The multi-point characteristic values of displacements are integrated via the CHC method to obtain the characteristic values representing the integral qualitative concept of the tailings dam, which can overcome the limitation of single-point early warning. The normal operation value of displacement of tailings dam is calculated according to the "3En" principle, and the comprehensive early warning displacement thresholds are obtained. The displacement monitoring data of Yangjiawan tailings dam demonstrates the rationality and accuracy of the developed CT–CHC model. Our work provides a new avenue to warn of the potential failure of tailings dams. [ABSTRACT FROM AUTHOR]

Tragic incidents involving mine tailings spills have impacted many aquatic ecosystems around the world. The massive mine tailings dam collapse of Fundão, which occurred in Brazil in 2015, affected several aquatic ecosystems, including shallow and deep lakes in the lower Doce River basin. Until now, the effects of mine tailings on the functional diversity of zooplankton remain poorly understood.We investigated the functional diversity of zooplankton (functional groups, functional richness [FRic] and functional evenness [FEve]) in shallow and deep lakes, exploring the influence of environmental variables and metals. In addition, trends in functional redundancy and functional vulnerability were also assessed to understand patterns of resilience in mining‐impacted ecosystems.Surveys were performed monthly on three deep and three shallow lakes affected by the dam failure, from October 2018 to September 2019.In the deep lakes, the zooplankton community was dominated by smaller filter‐feeders and omnivorous species, associated with cyanobacteria density and chlorophyll‐a. Medium‐sized filters were associated to iron, suspended particulate organic matter and total organic carbon in shallow lakes. The smaller filter‐feeders and omnivorous trophic groups had a higher contribution to increasing the functional diversity of zooplankton than medium‐sized filter‐feeders in both deep and shallow lakes. FRic and FEve were higher in deep lakes than in shallow lakes. Shallow lakes were highly vulnerable to species loss and functional diversity was modulated by environmental changes and metal pollution.Tropical shallow lakes impacted by mining tailings should receive particular attention in conservation plans, as a consequence of their high level of pollutant retention in comparison with deep lakes. In addition, we highlight the importance of using a functional approach to better understand the ecosystem changes resulting from the impacts of mine tailings on aquatic environments. [ABSTRACT FROM AUTHOR]

The recent catastrophic failures of tailings storage facilities (TSFs) have generated an enormous interest amongst the stakeholders for safe management of tailings. Two state parameters, namely moisture content and density of the deposited tailings, are the key to assess their degree of densification in the TSF. To that end, electromagnetic (EM) methods are strong candidates for health monitoring of TSFs as they provide a means to determine moisture content and density of porous media in a minimally invasive manner. In this paper, we have shown the applicability of two EM methods, i.e. time-domain reflectometry (TDR) and high-frequency electromagnetic (HF-EM) measurements for estimation of the degree of wetness and density of an iron oxide copper gold deposits (IOCG) tailings sample sourced from an operational mine in Australia. Through TDR measurements, we have demonstrated estimation of gravimetric moisture content, volumetric moisture content, degree of saturation, dry density and electrical conductivity of several reconstituted samples prepared at known moisture content and density. Furthermore, we have also discussed on utilisation of HF-EM method for continuous time-lapse monitoring of gravimetric moisture content of an initially saturated sample undergoing progressive dewatering. It is expected that these two methods will be applicable for measuring moisture content and density of the stored IOCG tailings material in the TSF. These will also be useful in continuously tracking moisture content of the samples providing an indication of extent of progress of dewatering of tailings. It should be noted that the study provides a proof of concept of the methodology, and a broad range of tailings need to be tested to generalise the approach. [ABSTRACT FROM AUTHOR]

Tailings dam accidents can result in serious casualties and environmental problems. Therefore, it is necessary to analyze the factors affecting the safety of tailings dams. In this paper, the permeability characteristics of sedimentary fine tailings, including the degree of compaction, and the seepage failure of tailings dams are explored. The results indicate that the permeability coefficient gradually decreases with increasing fine-particle content. There is a threshold associated with the fine-particle content at which the trend in the coefficient changes. The fine-particle content at this threshold is 35% for particles finer than 0.075 mm and 15% and 30% for particles finer than 0.005 mm. At a given fine-particle content, the permeability coefficient of horizontal sampling tailings is the largest, followed by that of uniform tailings, with the permeability coefficient of vertical sampling tailings being the smallest. When low pressure is applied to tailings containing fewer fine particles, even though the pores are reduced in size, they are still connected. Only under high-pressure conditions can the connectivity of the pores of tailings containing few fine particles be reduced. When the fine-particle content increases, the fine particles fill the spaces between the coarse particles. Low-pressure conditions can then reduce the connectivity of the pores. [ABSTRACT FROM AUTHOR]

Recent disasters involving upstream raised tailings dams in Brazil have caused regulatory agencies to prohibit the construction of new upstream dams and demand the decommissioning of existing ones. As such, new alternatives are being sought to safely dispose of iron ore exploitation byproducts. The dry stacking of filtered tailings is an option to diminish the risks associated with tailings storage facilities and cope with new legislation. Accordingly, this paper studies new solutions for enhancing the performance of tailings for dry stacking purposes. The behavior of reinforced and nonreinforced iron ore tailings-alkaline-activated cement (AAC) blends was studied through unconfined compressive strength tests and conventional triaxial testing. The AAC is produced from the residues of iron ore exploitation (waste and tailings). The addition of fibers has enhanced the performance of cemented iron ore tailings with increased strength regardless of the fiber content and ductility. Also, reinforcement effectiveness values were greater than those reported for other cement agents, due to the lower stiffness of the cemented matrix from AAC compared with others. A comparative analysis between using only AAC and ACC plus 0.5% of fibers within the η/Biv framework was proposed. The dosage curves for the same qu value yielded an AAC=20.80% for AAC only and AAC=3.80% when using 0.5% of fibers. Therefore, using fibers can collaborate with the feasibility of using a new waste-based AAC to construct dry stacking facilities. [ABSTRACT FROM AUTHOR]

Purpose. To assess the impact of mining waste on the heavy metal content of water surfaces, plants, and topsoil near the tailings dam of a Zn-Pb mine using both biotests and analytical methods. Methodology. A battery of microbiotests on different animal and plant species was carried out, making it possible to evaluate the toxic effect of residues and surrounding soils on living organisms. Furthermore, the possible relationship between the observed toxicity and the results of the physicochemical analysis of the samples was studied. Findings. The tests showed that the topsoil in contact with the tailings dam is slightly toxic to the living organisms used while the mining tailings are toxic or even very toxic. The heavy metal content of the samples is particularly high for Fe, Zn, Pb and Cu. The correlation of physic-chemical parameters and the results of microbiotests using the principal components analysis (PCA) and the multiple correspondence factor analysis (MCFA) indicate that the toxicity of tailings and the surrounding topsoil can be associated with anthropogenic mining activity. Originality. The study aimed to assess the impact of mining waste on the heavy metal content using biotests and analytical methods. The evaluation considers the concentrations of the samples (highly concentrated samples and samples after dilution) and the different phases of exposure (solid, liquid) for a more detailed assessment of the potential toxicity of the samples. Practical value. It is important to conduct a comprehensive assessment of mining waste and the risks it may pose to humans and the environment in order to develop an adequate rehabilitation plan. [ABSTRACT FROM AUTHOR]

BACKGROUND AND OBJECTIVES: Gold mining wastes have long been a significant concern in Agusan del Sur, a gold mining district in the Philippines. The region is vulnerable to climate change effects such as typhoons and flooding, which may lead to contaminated runoff or overflow that could potentially harm the local agriculture and adjacent natural ecosystems. This study aims to analyze the properties of the gold mill tailings, investigate their potential for reutilization, and identify areas that need improvement in order to promote an inclusive approach towards the valorization of mine waste. METHODS: The samples were collected randomly from a small- scale gold mill tailings storage facility. The samples underwent analysis for elemental and oxide composition, particle dimensions, potential of hydrogen, lead, mercury, free cyanide and hexavalent chromium. A gap analysis was utilized to pinpoint the methods for enhancing a socially inclusive reuse strategy for the mill tailings. FINDINGS: The characterization of the tailings reveal that some heavy metals like zinc, titanium, copper, barium, and manganese, and hazardous substances like arsenic, mercury, and lead are present. Elevated levels of mercury, lead, and free cyanide were detected in the wastewater, with concentrations of 0.029 milligram per liter, 0.40 milligram per liter, and 1.9 milligram per liter, respectively, surpassing the allowable thresholds. There is a high risk of contaminating the neighboring ecosystem during flooding events and waste overflow. The tailings also contain fine particles of about 75 percent fine sand and 25 percent clay. Adequate maintenance of tailings storage facilities, community awareness of waste-related risks and hazards, legal frameworks and financial backing to encourage waste utilization, local community empowerment, and adherence to occupational health and safety guidelines in waste management are essential strategies to bridge existing disparities and foster a socially inclusive approach to mine waste valorization. CONCLUSION: The gold mill tailings contain hazardous substances and fine dust, potentially damaging the nearby ecosystem and community. It is essential to prioritize the maintenance of a well-managed tailings storage facility in order to avoid contamination. The reuse of gold mill waste tailings can bring about economic, social, and environmental advantages. However, there are gaps that must be addressed to achieve a socially inclusive gold mill waste circularization. The utmost importance should be placed on the health and safety aspect, and it is advisable to carry out a comprehensive investigation into the degree to which hazardous substances are polluting the surrounding ecosystem, including the local community. [ABSTRACT FROM AUTHOR]

The Global Industry Standard on Tailings Management (GISTM) promotes performance-based approaches in geotechnical assessments. Hence, characterizing the spatial variability of deposited tailings is expected to be a key input for some tailings storage facilities (TSFs); however, it has seldom been investigated. In this study, we assess the spatial variability of thickened and conventional tailings, which have been deposited into the same TSF, providing a unique opportunity to investigate two tailings technologies. A dense array of 15 cone penetration tests (CPTus) with an average offset of 1.5 m has been conducted to collect data. In addition to evaluating the spatial variability, the collected information is also used to assess the potential of machine learning (ML) for detrending when deriving random fields. Using a new proposed stationarity score, we find that an ML-based detrending outperforms traditional procedures for most scenarios. In terms of correlation lengths, we find similar ranges for thickened and conventional tailings (vertical: δwv=0.2–0.6 m , horizontal δwh=1.5–4.5 m) and similar distributions, likely influenced by the depositional processes. In contrast, the variance in the conventional tailings is higher, which we attribute to its segregating nature. Finally, by inspecting previous studies on natural soils, we find that the variability of mine tailings (δwh/δwv=2–21) resembles that observed in alluvial deposits, which we attribute to the parallels in the depositional processes. [ABSTRACT FROM AUTHOR]

Several tailings dam failures have highlighted the potential for instability under prevailing drained conditions, which can be represented in the laboratory using constant shear drained (CSD) loading. In this study, the mechanical response of three mine tailings gradations (coarse, intermediate, and fine) from a tin ore tailings storage facility subjected to CSD loading were evaluated. The experimental results were interpreted using the critical state soil mechanics framework and different instability criteria. Salient findings include the following: (1) the onset of instability in initially loose specimens was dictated by a tradeoff of volumetric strain components (i.e., elastic and plastic), which in turn governed the evolution of the dilatancy and plastic modulus, key properties for modern constitutive models that were also investigated in this study; (2) dense-type instabilities may occur for initial states above the critical state line; this response was observed in the fine tailings due to their compressibility and initial state before CSD stress relief; (3) variable rate tests suggested that drained creep in the intermediate tailings made the second-order work instability criterion unattainable; variable rate effects were manifested in the postinstability responses of the intermediate and fine tailings but not in those of the coarse tailings; and (4) existing instability criteria perform similarly when applicable, but they also have limitations. In this context, a new criterion is proposed by modifying an existing criterion. This study advances the understanding of the mechanical response of mine tailings, under nonstandard stress paths. [ABSTRACT FROM AUTHOR]

Alluvial river channels respond to changes in sediment supply by adjusting their geometry. Landslide sediment delivery and geomorphic response of river channels during floods are poorly understood and rarely examined in tropical settings. We investigate the impact of landslides on channel geomorphic changes during an extreme typhoon‐induced flood event in the Philippines, specifically the complex geomorphic response of the Antamok River to Typhoon Mangkhut in September 2018, which triggered >500 landslides in the Ambalanga catchment. The catchment has a legacy of anthropogenic modifications, such as extensive small‐scale (artisanal) mining and tailings storage facilities (TSFs) from large‐scale mining activities. We use a novel mix of mapping and computational modelling approaches to test the hypothesis that landslide sediment delivery is a major control on channel geomorphic change. Pre‐ and post‐event imagery show that the overall active channel area increased by 35.9% and the mean active channel width increased by 9.1 m. Spatially, we find no clear relationship between landslide sediment input or unit stream power and channel width geomorphic change, with longitudinal changes in active channel width complicated by TSFs. Multi‐phase modelling using r.avaflow revealed how landslide sediment delivery and TSFs interacted with the flow to generate the observed patterns of channel change. The model simulated channel incision in the upper parts of the catchment (up to 0.78 m) and deposition in the TSFs (up to 1.73 m). Our findings demonstrate that well‐established methods (e.g., stream power threshold) fail to fully explain channel width geomorphic changes, particularly for anthropogenically altered catchments. Integrating techniques, such as landslide mapping and multi‐phase computational modelling improves understanding of sediment supply's role in channel width change during extreme events. Numerical simulations also demonstrate that conventional assumptions of increased erosion and deposition with rising flow discharge are inaccurate with large sediment input, highlighting instead the effectiveness of multi‐phase models. [ABSTRACT FROM AUTHOR]

The rupture of the Fundão dam (Brazil) spread tailings contaminated with sodium and ether-amine into the Doce River Basin. Aiming at rehabilitating a contaminated riparian site, phytoremediation with native species of the Atlantic Forest was performed under four treatments: ES-1: physical remediation (sediment scraping) + chemical remediation (organic matter) + bioremediation (double inoculation with the arbuscular mycorrhizal fungus (AMF) Rhizophagus irregularis and the plant growth-promoting bacteria Bacillus subtilis); ES-2: chemical remediation + bioremediation; ES-3: physical remediation + chemical remediation; ES-4: chemical remediation. Ether-amine and sodium contents, plant growth and, soil quality parameters were compared among treatments and relative to preserved and degraded sites. Two years after planting, the outstanding plant growth was attributed to the phytoremediation of ether-amine and ammonium, followed by a significant increase in soil microbial biomass (Phospholipid fatty acids-PLFAs), particularly the Gram+ bacteria and total fungi but not AMF, whose response was independent of the inoculation. While sodium and ether-amine declined, soil K, P, NO3− contents, dehydrogenase and acid phosphatase activities, cation exchange capacity (CEC) and soil aggregation increased, especially in ES-1. Thus, such remediation procedures are recommended for the restoration of riparian areas affected by the Fundão tailings, ultimately improving sediment fertility, aggregation and stabilization. To the best of our knowledge, this is the only successful example of fragment of riparian Atlantic Forest successfully rehabilitated using native trees from the Atlantic Forest in the riparian zone affected by the contaminated Fundão dam tailings. For that, phytoremediation and bioremediation procedures were adopted to alleviate etheramine and sodium toxicity, resulting in the amelioration of soil fertility and particularly the stabilization of such highly disaggregated sediments, ultimately protecting the Doce river basin against these contaminants. [ABSTRACT FROM AUTHOR]

Rhizospheric microbial communities improve the effectiveness of hyperaccumulators in the phytoremediation of heavy metals. However, limited access to tailing dams and inadequate assessment of plants' phytoremediation potential limit the characterization of native accumulators, hindering the effectiveness of local remediation efforts. This study evaluates the heavy metal sequestration potentials of Pennisetum purpureum, Leucaena leucocephala, and Pteris vittata and their associated rhizospheric microbial communities at the Marlu and Pompora tailing dams in Ghana. The results indicate shoot hyperaccumulation of Cd (334.5 ± 6.3 mg/kg) and Fe (10,647.0 ± 12.6 mg/kg) in P. purpureum and L. leucocephala, respectively. Analysis of rhizospheric bacterial communities revealed the impact of heavy metal contamination on bacterial community composition, associating Fe and Cd hyperaccumulation with Bacillus, Arthrobacter, and Sphingomonas species. This study reports the hyperaccumulation potentials of L. leucocephala and P. purpureum enhanced by associated rhizosphere bacterial communities, suggesting their potential application as an environmentally friendly remediation process of heavy metals contaminated lands. The novelty of this study is the report of the heavy metal accumulation potentials of the fast-growing herbaceous plants Leucaena leucocephala and Pennisetum purpureum at abandoned gold mine tailing dams in Ghana. Substantial amounts of Cd (334.5 mg/kg) and Fe (10,647.0 mg/kg) were accumulated in P. purpureum and L. leucocephala shoots, indicating their hyperaccumulation potentials. The concentration of heavy metal levels in the rhizosphere influenced the bacterial community structure, with the abundance of Bacillus, Arthrobacter, and Sphingomonas linked to hyperaccumulation. The outcome of this study supports the utilization of L. leucocephala and P. purpureum in the phytoremediation of lands contaminated with heavy metals. [ABSTRACT FROM AUTHOR]

The mining industry generates vast quantities of mine tailings on an annual basis. However, due to their limited economic value, a significant portion of these tailings are deposited close to mining sites, often underwater. The principal environmental apprehensions associated with mine tailings revolve around their elevated levels of heavy metals and sulfidic minerals. The oxidation of these sulfidic minerals can lead to the formation of acid mine drainage, which in turn releases heavy metals into nearby water systems. The effective management of tailing dams requires substantial financial investments for their construction and meticulous control. Consequently, a pressing need exists for stable, sustainable, and economically viable management approaches. One promising method for addressing mine tailings is through alkali activation, a technique that serves as a stabilization process. This approach yields robust, concrete-like structures by utilizing raw materials abundant in aluminum and silicon, which conveniently constitute the primary components of mining residues. This comprehensive review outlines the research on utilizing alkali activation for mine tailings. It delves into the reactivity and chemical attributes of diverse minerals. Numerous mine tailings exhibit an inadequate level of reactivity under alkaline conditions, so various pre-treatment methodologies and their impacts on mineralogy are meticulously explored. [ABSTRACT FROM AUTHOR]

Featured Application: Iron ore tailings are amongst some of the most common and widely available types of mining waste. This paper focus on the geotechnical characterization of these materials in order to promote their potential applications as building materials in more sustainable geotechnical works, namely in embankments, employing the concept of circular economy. The mining industry produces large amounts of tailings which are disposed of in deposits, which neglects their potential value and represents important economic, social and environmental risks. Consequently, implementing circular economy principles using these unconventional geomaterials may decrease the wide-ranging impacts of raw material extraction. This paper presents an experimental characterization of iron ore tailings, which are the most abundant type of mining waste. The characterization includes various aspects of behavior that are relevant to different types of use as a building material, including physical and identification properties, compaction behavior and stress–strain properties under undrained monotonic and cyclic triaxial loading. The tailings tested can be described as low-plasticity silty sand materials with an average solids density of 4.7, a maximum dry unit weight close to 3 g/cm3 and a higher angle of friction and liquefaction resistance than common granular materials. The experimental results highlight the particular features of the behavior of iron ore tailings and emphasize the potentially promising combination of high shear resistance and high density that favors particular geotechnical applications. Overall, the conclusions provide the basis for promoting the use of mining wastes in the construction of sustainable geotechnical works and underpin the advanced analysis of tailings storage facilities' safety founded on an open-minded geotechnical approach. [ABSTRACT FROM AUTHOR]

This study provides a predictive analysis of the potential disaster trajectory and extent of a tailings dam in Guangdong Province using GDEM-GAVA technology. Tailings dam failures are complex events characterised by high non-linearity and unpredictability. The research results show that the tailings debris flow followed an inverted V-shaped pattern. The tailings sand travelled approximately 800 m down the valley, with the furthest edge reaching 1387 m and the widest cross-valley spread at 90 m. The average deposition thickness was approximately 6 m and the peak velocity of the debris during erosion reached approximately 35 m per second. In particular, the debris flow engulfed and eroded significant parts of the processing plant, including the main plant area, the washing and screening workshop and the thickener basin. It also affected the storage area, covering approximately 10,000 square m. These findings provide an important scientific basis for early warning and risk assessment of potential tailings dam failures. [ABSTRACT FROM AUTHOR]

This paper is a summary of many of the key findings on the application of geosynthetics in tailings storage facilities. Topics include the compressibility and permeability of tailings, the equations predicting leakage through circular and non-circular geomembrane holes, the effect of the subgrade permeability, and the effect of a lateral drainage system within tailings on leakage predictions. Two commonly encountered engineering problems relating to the piping through circular geomembrane holes and the opening width of non-circular defective geomembrane seams are given to demonstrate the potential application of leakage prediction equations. Meanwhile, issues related to the subgrade imperfection and the long-term performance of both high-density polyethylene (HDPE) and bituminous geomembranes in tailings storage applications are addressed. The research highlights that an appropriate HDPE geomembrane liner can be expected to perform very well for an extremely long time, limiting leakage and contaminant migration from the facility into the surrounding environment if the liner is well constructed on a suitable subgrade. [ABSTRACT FROM AUTHOR]

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The Samarco/Vale/BHP mine tailing dam breach that took place in Minas Gerais, southeastern Brazil, in 2015, deposited high concentrations of metals and metalloids in the Rio Doce basin, severely impacting freshwater and riverine forest ecosystems. To assess developmental instability of caddisflies in response to the environmental impacts of the dam breach, we investigated the fluctuating asymmetry (FA) in the species Smicridea (Rhyacophylax) coronata (Trichoptera: Hydropsychidae). FA was assessed at individual and populational scales using geometric morphometric methods in the cephalic capsule and mandibles of larvae and also on the forewings of adults, both collected under the impacted condition, and under the least disturbed condition. The levels of FA increased in response to stressors on the forewings at the populational scale, and on the mandibles, at individual scale. These morphological variations in the larval and adult stages may lead to detrimental effects and result in high mortality rates as well as lower adult fitness. Trichoptera forewings are revealed as suitable traits for assessing FA, holding potential for applications in biomonitoring programs. Directional asymmetry levels were higher than FA levels for all traits, and this correlation could be explained by a transition from fluctuating to directional asymmetry in the presence of heightened disturbance. Our results validate the relationship between the impacts from the dam breach and increased developmental instability in this species with likely cascade effects on the insect community. [ABSTRACT FROM AUTHOR]

A method to assess the influence of tension cracks on the seismic external stability analysis of geosynthetic-reinforced soil slopes is carried out in the present study. In addition to being subjected to uniform surcharge loading, hydrostatic and hydrodynamic pressures with water on both sides of the c-ϕ soil slope and seismic inertia forces are considered, and the reinforcement length for both sliding and overturning conditions is evaluated by using a two-part wedge mechanism. The analysis is implemented separately by considering and neglecting the effect of the formation of tension cracks, and reinforcement lengths are evaluated for both the slope angles 60° and 70°. It is seen that when the horizontal seismic acceleration coefficient increases from 0 to 0.2 for a 60° slope angle under the direct sliding mode of failure for a particular set of input parameters as shown in Table 3, the required minimum length of the geosynthetic reinforcement increases from 0.59H to 1.30H, and in the overturning mode, it increases from 0.46H to 0.60H, when the analysis is implemented without considering similar tension cracks when tension cracks are considered in the study, for the increases in kh, as mentioned previously, required minimum length of the geosynthetic reinforcement against direct sliding mode of failure increases from 0.80H to 1.67H, and increases from 0.55H to 0.64H for overturning mode of failure. In addition to kh, the influence of the height of water on the downstream side, pore pressure ratio, soil friction angle, cohesion, and surcharge on the length of reinforcement against sliding and overturning modes of failure are presented in this paper in the form of design charts. The results obtained from the present study are compared with the previous literatures and usefulness of the present method in analysis of reinforced soil slopes against direct sliding and overturning modes of failure has been proposed. The present research work delves into the external stability analysis of reinforced soil slopes. This analysis evaluates the optimal length of reinforcement necessary to maintain long-term safety and stability against potential failures, such as direct sliding and overturning. While direct sliding is influenced by forces pushing the slope forward, overturning is concerned with rotational risks. Geosynthetic reinforcement for soil slope stability plays a crucial role in stabilizing slopes across various infrastructures: highways, railways, airports, landfills, mining operations such as tailings dams and heap leach pads, urban developments, and erosion control measures along riverbanks and shorelines. Adopting the insights and methodologies of this research can amplify the safety benefits by reducing landslide risks and facilitating the customization of designs according to specific site conditions. This approach paves the way for a more efficient use of resources, ultimately slashing costs and bolstering the long-term reliability of slope performance. Furthermore, the study presents a clear analysis of geosynthetic-reinforced soil slopes, considering soil properties, failure risks, seismic forces, and water effects. This framework, suitable for both experts and novices, bridges academic research with practical engineering, making the latest insights usable and valuable for the engineering community. [ABSTRACT FROM AUTHOR]

Concrete materials are widely used in engineering projects, with fine aggregates (sand) being a key component currently in short supply. Copper tailings sand, a waste by-product of copper mining, accumulates in large quantities in tailings dams. Recycling and reusing this waste sand is crucial for environmental sustainability. This paper investigated the incorporation of copper tailings sand into concrete as a partial replacement for fine aggregates and evaluated its effects on concrete's workability and mechanical properties. The experimental results indicate that the addition of copper tailings sand reduced the workability and compressive strength of concrete. Specifically, at a 60% substitution rate, the slump of the concrete was reduced by 15%, and the axial strength was closest to that of ordinary concrete, with a reduction of 2.5%. As the proportion of copper tailings sand increased from 0% to 80%, the average axial strength decreased from 37.3 MPa to 34.9 MPa, and stiffness decreased by approximately 6.43%. A complete stress–strain curve equation was proposed based on fitting relevant parameters, closely aligning with experimental data. Moderately adding tailings sand can help address the issue of large amounts of waste sand accumulating in tailings dams while maintaining acceptable concrete properties. [ABSTRACT FROM AUTHOR]

The rupture of an iron mining tailing dam in Brumadinho, Brazil, released around 10 million cubic meters of tailings, of which 1.6 Mm3 reached the Paraopeba River. In this work, a total of 30 samples from three bottom sediment cores were collected in the lower course of the Paraopeba River basin and analyzed for major, trace and rare earth elements by ICP-OES and ICP-MS. The sediments presented a range of compositions with different weathering histories, overall marked by depleted Ca2+, Na+ and K+ compared with the average UCC, PAAS and NASC and some advanced weathering trends. The samples presented a fractionation pattern characterized by a continuous depletion of light REEs from La to Sm and a regular decreased distribution of heavy REEs from Gd to Yb, and the Co/Th vs. La/Sc diagram indicates a predominant intermediate source. The upper samples presented the highest contents of REEs, probably due to the higher presence of iron and aluminum oxides and hydroxides, which can be related to more advanced weathering. The Al, Cu, Ni, V, Zn, Co, Mn, Ti, Fe and Si concentrations and the CF, EF and Igeo index values varied across the sediment core samples, demonstrating that there were long periods of geogenic or anthropogenic contributions. [ABSTRACT FROM AUTHOR]

The awareness of tailings dam safety monitoring has widened due to the recent disasters caused by failures of such structures. The failure rate of tailings dams worldwide (i.e., the percentage of failed dams out of total) is estimated at 1.2%, compared to the 0.01% rate for traditional water dams. Most of the tailings dam monitoring guidelines suggest that the owner develops a robust surveillance program to detect possible indicators of potential failures. This paper presents a thorough review of major guidelines on tailings storage facility (TSF) monitoring and surveillance, the visual parameters to be monitored, as well as good practice in the development of monitoring systems. This paper reviews the recent literature with an emphasis on the development of monitoring systems utilizing sensors, unmanned aerial vehicles (UAVs), and satellite images that may be considered as supplementary guarantees against failure events. [ABSTRACT FROM AUTHOR]

Seepage damage is a significant factor leading to red mud tailings dam failures. Laboratory tests on seepage damage were conducted to investigate the damage characteristics and distribution laws of red mud tailings dams, including soil pressure, infiltration line, pore water pressure, dam displacement, and crack evolution. The findings revealed the seepage damage mechanisms of red mud slopes, offering insights for the safe operation and seepage damage prevention of red mud tailings dams. The results showed that the higher the water level is in the red mud tailings dam, the higher position the infiltration line is when it reaches the slope face. At the highest infiltration line point of the slope surface, the increase of pore water pressure is the highest and the change of horizontal soil pressure is the highest. Consequently, increased pore water pressure leads to decreased effective stress and shear strength, increasing the susceptibility to damage. Cracks resulting from seepage damage predominantly form below the infiltration line; the higher the infiltration lines is on the slope surface, the higher the position of the main crack formations is. The displacement of the dam body primarily occurs due to the continuous expansion of major cracks; the higher the infiltration lines are on the slope surface, the larger the displacement of the dam body is. [ABSTRACT FROM AUTHOR]

Industrialized countries attempted to obtain minerals, resulting in a developed method to extract valuable minerals from the ground. Consequently, waste mine tailings are produced and, when left to pile up, will potentially be hazardous to the environment and the people. However, more mine tailings become a problem when the organization needs clarification on the minerals' value and what they can be used for. This study focuses on a multi-criteria analysis of the potential repurposing of the Philex Mining Corporation (PMC) tailings in Benguet, Philippines. While mining policies were considered, findings show that piles of mine tailings had not been considered for refining to produce more resources for development, construction, and economic growth The study employs qualitative inquiry to understand better the grassroots processes and reconnaissance of the stored tailings. The analysis tries to promote sustainable practices -- presenting a higher sustainability priority, resource conservation, and the responsible management of mining waste, making it a more favorable alternative to traditional tailing storage facilities. Several industrial uses for the tailings have been suggested to reinforce waste diversion. [ABSTRACT FROM AUTHOR]

Copyright of Revista Foco (Interdisciplinary Studies Journal) is the property of Revista Foco and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Tailings storage facility (TSF) failures have tremendous impacts on surrounding populations, communities, and ecosystems. Therefore, a three-dimension risk matrix considering failure probability, event intensity, and exposure of failure-bearing bodies is established to assess the risk of TSF failure. First, based on the established assessment indicator system, the probability level is determined by the uncertainty measurement theory combined with the extension analytic hierarchy process. Then, the event intensity level is determined by two parameters, namely the volume of released tailings and the maximum distance traveled by tailings. The exposure level is characterized by the potential loss of four failure-bearing bodies, including population, economy, environment, and society. Finally, the risk index is calculated by the Euclidean distance method and the risk level is determined. In the proposed model, the probability, intensity, exposure, and the risk of TSF failure are all divided into four levels (Level I, Level II, Level III, Level IV) from high to low. The application of the case verifies the applicability and availability of the proposed model. [ABSTRACT FROM AUTHOR]