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This study used steel slag, fly ash, and metakaolin as raw materials (SFM materials) to create silica-alumina-based geopolymers that can solidify Hg2+ when activated with sodium-based water glass. The experiments began with a triangular lattice point mixing design experiment, and the results were fitted, analyzed, and predicted. The optimum SFM material mass ratio was found to be 70% steel slag, 25% fly ash, and 5% metakaolin. The optimum modulus of the activator was identified by comparing the unconfined compressive strength and solidifying impact on Hg2+of geosynthetics with different modulus. The SFM geopolymer was then applied in the form of potting to cure the granulated mercury tailings. The inclusion of 50% SFM material generated a geosynthetic that reduced mercury transport to the surface soil by roughly 90%. The mercury concentration of herbaceous plant samples was also reduced by 78%. It indicates that the SFM material can effectively attenuate the migration transformation of mercury. Finally, characterization methods such as XPS and FTIR were used to investigate the mechanism of Hg2+ solidification by geopolymers generated by SFM materials. The possible solidification mechanisms were proposed as alkaline environment-induced mercury precipitation, chemical bonding s, surface adsorption of Hg2+ and its precipitates by the geopolymer, and physical encapsulation.

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Herein, a novel graphite/sulfur iron tailing composite was applied as a peroxydisulfate (PDS) activator for rhodamine B (RhB) degradation in the water. The superior catalytic efficiency of graphite/sulfur iron tailing was achieved through radical (SO4•- and •OH) and non-radical (1O2) processes according to the radical quenching experiments and electron paramagnetic resonance analysis. The carbonyl group and Fe species were the main active sites on the surface of graphite/sulfur iron tailing, which was demonstrated by combining Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), and reaction kinetic experiments, and a possible degradation mechanism was also proposed. Overall, activated with 0.30 g/L of C-1, PDS achieved a 94.8% removal rate for RhB and maintained a removal rate of over 85% even after five consecutive operation cycles, and this study will benefit the application of iron/carbon composite materials in practical water treatment.

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This study aimed to recover high-purity silica from hematite tailings (HTs) using superconducting high-gradient magnetic separation (S-HGMS) technology. This process involved converting silica into a silicone-rich concentrate and subsequently employing a fluorine-free mixed acid to leach the silicon-rich concentrate to remove impurities and achieve refinement and purification. The optimization of the S-HGMS process was conducted using the "Box-Behnken Design" method, resulting in the following optimal conditions: a pulp concentration of 50 g/L, a magnetic velocity ratio of 0.076 T s/m, and a pulp velocity of 500 mL/min. These conditions yielded a silica grade range of 61.905% in the HTs to 91.818% in the silicon-rich concentrate, with corresponding recovery rates of 53.031%. Under the optimized leaching process, this resulted in an increase in the silica content from 91.818% in the silicon-rich concentrate to 99.938% in high-purity silica. Additionally, by analyzing the production process of 1 kg of high-purity silica from HTs using the process LCA method, environmental hotspots were identified, and corresponding solutions were proposed. This approach is vital for efficient utilization of HTs as a resource. This process has low energy consumption and is environmentally friendly, enabling the reduction of hematite tailings. It has a wide range of applications and offers substantial economic benefits, rendering it a promising candidate for industrial applications.

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Waste is the materials left over after the processing of ores. Significant disasters involving waste disposal structures have occurred in Brazil in recent years and caused severe damage by contaminating soil, rivers and coastal areas, destroying native fauna and flora, interrupting the water supply and compromising its potability, putting the population's health, livelihoods and economy at risk, as well as causing 289 irreparable human deaths. Regulatory laws have become stricter, and since 2019, after the tailings dam tragedies occurred in 2015 and 2019 in Mariana and Brumadinho, in Minas Gerais, the operation of  upstream-raised tailings dams has been prohibited in Brazil. In 2022, a waste slide from a sterile pile at the Pau Branco Mine in Nova Lima promoted a dike overflow. There was the death of five people whose car was buried by a landslide on a hillside. New strategies and technologies, such as reprocessing and recycling, can be tested to ascertain whether they can help improve practices in tailings management. Indeed, mining companies' corporate responsibility and sustainability practices need to be evaluated to verify whether they better match expectations. On the other hand, more specific and detailed regulations and resolutions are required to ensure the safe monitoring and management of sterile waste piles. This paper presents a review of the facts, a discussion of the literature (mainly on recent tailings dam disasters), the current situation of mining-containing waste structures in Brazil, a brief sustainability analysis and perspectives aimed at preventing/minimising catastrophes in the future.

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Knowledge about the characteristics of overburden and tailings from manganese (Mn) mining is essential for defining their levels of potentially toxic elements (PTEs) and appropriate environmental management. This study aimed to assess the total and bioavailable contents of PTEs in Mn mining areas in the Eastern Amazon, as well as the associated environmental risks. The samples were collected in areas of overburden and tailings deposition, in addition to forest soils in the Azul mine, Carajás Mineral Province, Brazil. These samples were characterized in terms of fertility, granulometry, and total and bioavailable PTE contents. The pH values of the forest soil were more acidic than those of the overburden and tailings, and the organic matter contents were considerably higher in the forest soil. All PTEs, especially Mn, Ba, Cu, Zn, and Pb, presented higher contents in the overburden and tailings. However, chemical fractionation revealed that PTEs were predominantly in the residual fraction, with percentage contents above 60% of the total content. These results suggest a low risk of environmental contamination. The findings of this study may support more efficient environmental rehabilitation in Mn mining areas in the Amazon.

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With the development of industry and agriculture, eutrophication caused by increasing amounts of phosphorus in the environment has attracted people's attention. On the other hand, copper tailings (CT) is a kind of solid waste with large quantity, large area, and easy to cause groundwater and soil pollution. CT is also a potential resource because of its large specific surface area. CT is intended to be used as an adsorbent for removal phosphate in water, but trace heavy metals and a small amount of phosphate in CT may bring negative effects. Calcium hydroxide (Ca(OH)2) was used to modify CT (CCT), hoping to fix the heavy metals and phosphate in CT at the same time. It was found that the removal capacity of CCT was significantly higher than that of CT. The process of phosphate removal by CCT involves electrostatic sorption and surface precipitation, and there is a synergistic effect between CT and Ca(OH)2. The phosphate removal rate of CCT-0.4 increased with the increase of pH value under alkaline conditions. The XRD patterns of phosphate sorption by CCT mean that Ca3(PO4)2, Ca5(PO4)3(OH) and AlPO4 exist in CCT after phosphate removal, indicating that surface precipitation occurs during the removal process. In summary, the removal mechanism of phosphate by CCT is mainly electrostatic attraction and surface precipitation.

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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 S2O3 2- 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 [S2O3 2-] and limited acidity generation. The S4I pathway part 1 (tsdA; S2O3 2- to S4O6 2-), was not constrained by pH, while S4I pathway part 2 (S4O6 2- 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, S2O3 2- 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 [S2O3 2-] manipulation.

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Mercury (Hg) pollution in Ghana through mining has become a serious environmental challenge. This study investigates the potential of Cirsium arvense to photostabilize Hg using electrokinetic current with or without an iodide solution in gold mine tailings heavily contaminated through mining activities in southern Ghana. An initial Hg concentration of 9.60 mg/kg using cold vapor atomic absorption spectrometry (CVAAS) was determined. The biological absorption coefficient, bioconcentration factor, and translocation factor of Hg have been presented. Cirsium arvense therefore had a higher bioconcentration factor (BCF) of 2.6-5.15 mg/kg, and a transfer factor (TF) of 0.24-0.36 indicating a higher efficiency for phytostabilization. Both the rate and time of extractions of Hg from the tailings by Cirsium arvense are efficiently improved in the combined electric current and iodide treatment. Plant and electric current combined treatment and plant and iodide combined treatment had only 60 and 50% phytostabilization rates, respectively. The combined plant, iodide, and electric current treatment has proven to be superior with about >90% Hg removal rate. Therefore, the combined plant, iodide, and electric current treatment resulted in a higher Hg removal efficiency by Cirsium arvense in a shorter period due to higher solubilization rate and electromigration effects on Hg species.

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Acid mine drainage （AMD） is of great concern owing to its safety hazards and environmental risks. However, little is known about the effects of AMD leakage on soil physicochemical properties and bacterial communities in ecologically fragile desert steppe soils, especially in the soil profile. Therefore, an AMD-contaminated profile and clean profile were used as research objects respectively to investigate the effects of AMD on soil physicochemical properties and bacterial community composition, structure, and interactions in soil layers at different depths of desert grassland and, based on this, to analyze the driving factors of bacterial community changes. The results showed that AMD significantly decreased the pH and increased electrical conductivity （EC） and heavy metal content in the upper （0-40 cm） soil layer of the profile. The AMD-contaminated profile bacteria were dominated by Proteobacteria, Firmicutes, and Actinobacterota, whereas clean profile bacteria were dominated by Firmicutes and Bacteroidota, with Thermithiobacillus and Alloprevotella being the biomarkers for the contaminated and clean profiles, respectively. AMD contamination significantly reduced bacterial diversity and significantly altered bacterial community structure in the upper soil layers of the profile. The results of redundancy analysis showed that soil physicochemical properties explained 57.21% of the variation in bacterial community changes, with EC, TP, TN, As, Zn, and Pb being the main drivers of bacterial community changes. Network analyses showed that AMD contamination increased profile complexity, modularity, and intra-community competition, thereby improving bacterial community stability and resilience. In conclusion, the study provided useful information on the effects of AMD pollution on soil physicochemical properties and bacterial communities in desert steppe soils, which may help to improve the understanding of the ecological hazards of AMD pollution on soils in extreme habitats.

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Base Mine Lake (BML), the first full-scale demonstration of oil sands tailings pit lake reclamation technology, is experiencing expansive, episodic hypolimnetic euxinia resulting in greater sulfur biogeochemical cycling within the water cap. Here, Fluid Fine Tailings (FFT)-water mesocosm experiments simulating the in situ BML summer hypolimnetic oxic-euxinic transition determined sulfur biogeochemical processes and their controlling factors. While mesocosm water caps without FFT amendments experienced limited geochemical and microbial changes during the experimental period, FFT-amended mesocosm water caps evidenced three successive stages of S speciation in ∼30 days: (S1) rising expansion of water cap euxinia from FFT to water surface; enabling (S2) rapid sulfate (SO42-) reduction and sulfide production directly within the water column; fostering (S3) generation and subsequent consumption of sulfur oxidation intermediate compounds (SOI). Identified key SOI, elemental S and thiosulfate, support subsequent SOI oxidation, reduction, and/or disproportionation processes in the system. Dominant water cap microbes shifted from methanotrophs and denitrifying/iron-reducing bacteria to functionally versatile sulfur-reducing bacteria (SRB) comprising sulfate-reducing bacteria (Desulfovibrionales) and SOI-reducing/disproportionating bacteria (Campylobacterales and Desulfobulbales). The observed microbial shift is driven by decreasing [SO42-] and organic aromaticity, with putative hydrocarbon-degrading bacteria providing electron donors for SRB. Comparison between unsterile and sterile water treatments further underscores the biogeochemical readiness of the in situ water cap to enhance oxidant depletion, euxinia expansion and establishment of water cap SRB communities aided by FFT migration of anaerobes. Results here identify the collective influence of FFT and water cap microbial communities on water cap euxinia expansion associated with sequential S reactions that are controlled by concentrations of oxidants, labile organic substrates and S species. This emphasizes the necessity of understanding this complex S cycling in assessing BML water cap O2 persistence.

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Dispersion of potentially toxic elements associated with efflorescent crusts and mine tailings materials from historical mine sites threaten the environment and human health. Limited research has been done on traceability from historical mining sites in arid and semi-arid regions. Pb isotope systematics was applied to decipher the importance of identifying the mixing of lead sources involved in forming efflorescent salts and the repercussions on traceability. This research assessed mine waste (sulfide-rich and oxide-rich tailings material and efflorescent salts) and street dust from surrounding settlements at a historical mining site in northwestern Mexico, focusing on Pb isotope composition. The isotope data of tailings materials defined a trending line (R2 = 0.9); the sulfide-rich tailings materials and respective efflorescent salts yielded less radiogenic Pb composition, whereas the oxide-rich tailings and respective efflorescent salts yielded relatively more radiogenic compositions, similar to the geogenic component. The isotope composition of street dust suggests the dispersion of tailings materials into the surroundings. This investigation found that the variability of Pb isotope composition in tailings materials because of the geochemical heterogeneity, ranging from less radiogenic to more radiogenic, can add complexity during environmental assessments because the composition of oxidized materials and efflorescent salts can mask the geogenic component, potentially underestimating the influence on the environmental media.

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Mulch coverage of mining tailings can create anaerobic conditions and consequently establish an anoxic environment that promotes the metabolic processes of anaerobic microorganisms. This anoxic environment has the potential to decrease heavy metal mobility and bioavailability. While tailings exposed to sunlight have been extensively studied, research on the effects of microbial-mediated geochemical cycling of heavy metals in mulch-covered tailings is scarce. This study aimed to examine the effects of mulch coverage-induced alterations in the structures of tailing microbial communities on the biogeochemical processes associated with heavy metals. Mulch coverage significantly reduced the pH of the tailings and the tailings exhibited heavy metal bioavailability. Random forest analysis demonstrated that mulch coverage-induced changes in the As/Cd-contaminated fractions and nutrients (total organic carbon and total nitrogen) were the most crucial predictors of microbial diversity and ecological clusters in the tailings. Notably, different from direct metal(loid) immobilization, mulch coverage can facilitate heavy metal immobilization in tailings by promoting microbial-mediated Fe, S, and As reduction. Overall, this study demonstrated that mulch coverage of tailings contributed to a reduction in heavy metal mobilization, which can be attributed to shifts in microbial-mediated Fe, S, and As reduction processes.The study provides valuable insights into the potential of mulch coverage as a remediation strategy and underscores the importance of microbial-mediated processes in managing heavy metal pollution in tailing systems.

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Tailings dams' breaks are environmental disasters with direct and intense degradation of soil. This study analyzed the impacts of B1 tailings dam rupture occurred in the Ribeirão Ferro-Carvão watershed (Brumadinho, Brazil) in January 25, 2019. Soil organic carbon (SOC) approached environmental degradation. The analysis encompassed wetlands (high-SOC pools) located in the so-called Zones of Decreasing Destructive Capacity (DCZ5 to DCZ1) defined along the Ferro-Carvão's stream bed and banks after the disaster. Remote sensed water indices were extracted from Landsat 8 and Sentinel-2 satellite images spanning the 2017-2021 period and used to distinguish the wetlands from other land covers. The annual SOC was extracted from the MapBiomas repository inside and outside the DCZs in the same period, and assessed in the field in 2023. Before the dam collapse, the DCZs maintained stable levels of SOC, while afterwards they decreased substantially reaching minimum values in 2023. The reductions were abrupt: for example, in the DCZ3 the decrease was from 51.28 ton/ha in 2017 to 4.19 ton/ha in 2023. Besides, the SOC increased from DCZs located near to DCZs located farther from the dam site, a result attributed to differences in the percentages of clay and silt in the tailings, which also increased in the same direction. The Ferro-Carvão stream watershed as whole also experienced a slight reduction in the average SOC levels after the dam collapse, from nearly 43 ton/ha in 2017 to 38 ton/ha in 2021. This result was attributed to land use changes related with the management of tailings, namely opening of accesses to remove them from the stream valley, creation of spaces for temporary deposits, among others. Overall, the study highlighted the footprints of tailings dams' accidents on SOC, which affect not only the areas impacted with the mudflow but systemically the surrounding watersheds. This is noteworthy.

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The addition of polymer fibers to cemented paste backfill (CPB) has shown promise in enhancing mechanical properties, although it also introduces changes in rheological characteristics. This study aimed to investigate the influence of different types of polymer fibers, namely virgin commercial polypropylene fiber (CPPF), recycled tire polymer fiber (RTPF), and recycled tire rubber fiber (RF), on the rheological properties of CPB mixtures through an experimental program, and provide design references for CPB pipeline transport. The results revealed consistent reductions in bulk density upon the incorporation of polymer fibers into CPB, alongside varying impacts on slump. Specifically, the addition of CPPF had a mild effect, while RTPF caused a continuous decrease in slump, and RF exhibited minimal influence up to a 4% concentration, with substantial effects thereafter. Moreover, the inclusion of fibers led to increases in apparent viscosity parameters, with RTPF inducing the most significant changes, followed by varying responses from CPPF and RF. When using RTPF for CPB reinforcement, emphasis should be placed on enhancing technical indicators related to viscosity such as energy consumption and pipeline wear during pipeline transport. Furthermore, adjustments were necessary to account for flow curve instability resulting from interactions between fibers and the paddle, with the data aligning well with the Bingham model. The addition of fibers, particularly CPPF and RF, primarily influenced plastic viscosity rather than yield stress, underscoring the limitations of slump tests in assessing rheology.

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In this study, a high-Si (Si) adsorbent (APR@Sam) was prepared by acid leaching slag (APR) from lead-zinc (Pb-Zn) tailings based on high-temperature alkali melting technology. The synthesized Si-based materials were applied to aqueous solutions contaminated with Pb and cadmium (Cd) to investigate the crucial role of active Si in sequestering heavy metals. The adsorption capacities of APR@Sam and the Si-depleted material (APR@Sam-NSi) were studied under different pH and temperature conditions. The results showed that as the pH increased from 3 to 7, the adsorption capacity increased, the active Si content in the solution increased by 63 %, and the maximum pH of the solution after adsorption was 7.12. After the removal of active Si, the Pb (II) and Cd (II) adsorption capacities of APR@Sam decreased by 45 % and 11.96 %, respectively. OH- promoted the release of Si into the solution, enhancing the material's adsorption efficiency. The reaction mechanism is mainly attributed to surface complexation guided by Si-O and Si-O-Si bonds, metal cation exchange, and bidentate coordination. The results indicated that the Si component is critical for the removal of Pb (II) and Cd (II) by APR@Sam and provide valuable insights into resource recovery strategies from leaching residues.

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The presence of various contaminants in airborne dusts from metal mining sites poses obvious risks to human health and the environment. Yet, few studies have thoroughly investigated the properties of airborne particles in terms of their morphology, size distribution and chemical composition, that are associated with health effects around mining activities. This review presents the most recent knowledge on the sources, physicochemical characteristics, and health and environmental risks associated with airborne dusts from various mining and smelting operations. The literature reviewed found only one research on atmospheric dust associated with hydrometallurgical plants compared to a larger number of pyrometallurgical processes/smelters studies. In addition, there are relatively few works comparing the distribution of metals between the fine and coarse size fractions around mining sites. Our analysis suggests that (i) exposure pathways of metal(loid)s to the human body are defined by linking concentration data in human biosamples and contaminated samples such as soils, drinking water and food, and (ii) chitosan and its derivatives may serve as an environmentally friendly and cost-effective method for soil remediation, with removal rates for metal(loid)s around 70-95 % at pH 6-8, and as dust suppressants for unpaved roads around mining sites. The specific limit values for PM and metal(loid)s at mining sites are not well documented. Despite the health risks associated with fine particles around mining areas, regulations have tended to focus on coarse particles. While some air quality agencies have issued regulations for occupational health and safety, there is no global alignment or common regulatory framework for enforcement. Future research priorities should focus on investigating PM and secondary inorganic aerosols associated with hydrometallurgical processes and dust monitoring, using online metal(loid)s analysers to identify the driving parameters in the deposition and resuspension process.

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The reutilization of municipal wastes has always been one of the hottest subjects of sustainable development study. In this study, a novel biochar co-pyrolyzed from municipal sewage sludge and phosphorus tailings was produced to enhance the adsorption performance of the composite on Cu2+ and Cd2+. The maximum Cu2+ and Cd2+ adsorption capacity of SSB-PT were 44.34 and 45.91 mg/g, respectively, which were much higher than that of sewage sludge biochar (5.21 and 4.58 mg/g). Chemisorption dominated the whole adsorption process while multilayer adsorption and indirect interaction were also involved. According to the result of X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy and X-ray photoelectron spectrum (XPS), the load of CO32-, Mg2+, and Ca2+ on the surface of SSB-PT enhanced the precipitation and ion exchange effect. Posnjakite and CdCO3 were formed after the adsorption of Cu2+ and Cd2+, respectively. Besides, complexation, and metal-π interaction were also involved during the adsorption process. Therefore, this study offered a promising method to reuse sewage sludge and phosphorus tailings as an effective adsorbent.

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Mine environments in boreal and sub-boreal zones are expected to experience extreme weather events, increases in temperature, and shifts in precipitation patterns. Climate change impacts on geochemical stability of tailings contaminants and reclamation structures have been identified as important climate-related challenges to Canadian mining sector. Adapting current reclamation strategies for climate change will improve long-term efficiency and viability of mine tailings remediation/restoration strategies under a changing climate. Accordingly, mesocosm experiments were conducted to investigate associations of climate-driven shifts in microbial communities and functions with changes in the geochemistry of organic covers and underlying tailings. Our results show that warming appears to significantly reduce C:N of organic cover and promote infiltration of nitrogen into deeper, unoxidized strata of underlying tailings. We also observed an increase in the abundance of some nitrate reducers and sulfide oxidizers in microbial communities in underlying tailings. These results raise the concern that warming might trigger oxidation of sulfide minerals (linked to nitrate reduction) in deeper unoxidized strata where the oxygen has been eliminated. Therefore, it would be necessary to have monitoring programs to track functionality of covers in response to climate change conditions. These findings have implications for development of climate resilient mine tailings remediation/restoration strategies.

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The presence of heavy metals in mine tailings poses a serious threat to the surrounding environment. In this study, we aimed to stabilize Pb/Zn-containing mine tailings using modified fly ash (FA) with various alkali solutions. Notably, the modification of FA with Na2SiO3 (NaSi-FA) resulted in the most significant structure changes. To understand the adsorption mechanism of Pb and Zn by modified FA, batch adsorption experiments were conducted. Doubling the adsorption capacity for both Pb and Zn was observed in the modified FA samples compared to unmodified samples. These results could be attributed to the enhanced surface area and porous structure, providing more anchor sites for the heavy metal ions. Additionally, the adsorption of Pb and Zn was found to follow the Langmuir isotherm and pseudo-second order kinetic. Molecular dynamics simulations further supported the notion that Pb and Zn ions could effectively exchange with Na ions within the N-A-S-H gel network, ultimately solidifying them in its structure. Stabilizing Pb/Zn tailings with NaSi-FA resulted in a significant decrease in the leaching of Pb and Zn. Specifically, the leading amount decreased by 55.2% for Pb and 35.3% for Zn, showcasing the superior performance of this stabilization method. This reduction in leaching indicates effective compliance with environmental regulations regarding the containment of Pb and Zn.

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Understanding the strength behavior and leaching characteristics of mining tailings stabilized with alkali-activated cements in the short, medium, and long term is crucial for the feasibility of material applications. In this context, this study assessed the stabilization/solidification of iron ore tailings (IOT) using alkali-activated binder (AAB) composed of sugarcane bagasse ash and eggshell lime at curing times of 7, 28, 60, 90, 180, and 365 days. Additionally, leaching tests were conducted, along with the examination of possible changes in the chemical and mineralogical composition resulting from exposure to acidic environments. Tests included unconfined compression strength (UCS), leaching, X-ray diffraction, and Fourier-transform infrared spectroscopy for the IOT-AAB mixtures. The highest increase in UCS was observed between 7 and 60 days, reaching 6.47 MPa, with minimal variation thereafter. The AAB-bonded IOT exhibited no metal toxicity over time. Elements Ba, Mn, Pb, and Zn present in IOT and ash were encapsulated in the cemented matrix, with complete encapsulation of all metals observed from 90 days of curing time. The mineralogy of the stabilized/solidified tailings showed no changes resulting from leaching tests. Characteristic bands associated with the presence of N-A-S-H gel were identified in both pre-leaching and post-leaching samples for all curing times analyzed. Exposure to acidic environments altered bands related to carbonate bonds formed in the IOT-AAB mixture.

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