Ore Tailings Research Articles

Effect of Iron Ore and Copper Ore Tailings on Engineering Properties and Hydration Products of Sustainable Cement Mortar

Abstract The prohibition of river sand mining has drawn the attention of researchers in finding practicable alternatives. In the approach of finding these alternatives, it is essential to ensure minimal or zero impairment to the ecological balance, which can be mainly attained by making use of industrial waste/byproducts. The wastes from the mining industry are the major contributors in causing impairment to the environment, and their influence on the stability of mortars on using as fine aggregates needs to be systematically investigated with the view of long-term performance concerns. Thus, the present study explores the applicability of mine tailings and finding the optimum dosage in cement mortars by investigating the engineering properties and microstructure development with the aid of qualitative and quantitative analysis associated with hydration products. The studies confirm that the increased consumption of portlandite for secondary hydration reactions followed by the additional formation of calcium silicate hydrate (CSH) and calcium aluminum silicate hydrate (CASH) phases in mine tailing-based mortars helped in achieving a quality microstructure. These additional formations of CSH and CASH phases are also confirmed through Fourier transform infrared spectroscopy by identifying the shift of Si-O-Si stretching vibration bands toward a lower wavenumber. The lowering of calcium/silicate atomic ratio and increased formation of mineralogical compounds related to CSH and CASH in x-ray diffraction patterns also confirms the same. Gismondine, chabazite, and hillebrandite are the additional phases formed and found to take part in refining the pore structure. This enhanced performance of mine tailing mortars was also verified with the aid of a modified Andreasen and Andersen particle packing model. The formation of high-quality microstructure is reflected in the hardened properties of optimized cement mortar in the proportion of 20 % for iron ore tailing and 30 % for copper ore tailing.

Hydration and properties of hydrogen-based mineral phase transformation iron ore tailings as supplementary cementitious material

Almost all iron ore tailings (IOTs) required activation prior to use as SCMs, which limited their application in building materials. This study investigated HMPT-IOTs and discovered that they possess latent hydraulic and pozzolanic properties. In order to better utilize as SCM, mechanical properties, hydration reactions, hydration products, microstructure, and pores were comprehensively studied through mechanical tests, hydration heat tests, XRD, SEM, TG, and MIP. The results show that when HMPT-IOTs replace cement at 10 wt%, 20 wt% and 30 wt%, the compressive strength at 28 days is 41.9 MPa, 47.9 MPa and 37.5 MPa, respectively. When the substitution amount reaches 30 wt%, it will reduce the cumulative heat of hydration and promote early hydration reactions. The main hydration products are ettringite and Ca(OH)2. As the nucleation site of C–S–H, hydration products are interconnected, making the microstructure denser. At this substitution level, Ca(OH)2 consumption was about 2% at 28 days of age. Simultaneously, the total pore volume was only 0.01 mL/g greater than that of the control group, and the number of micropores and transition pores decreased by approximately 3%.

Adding Agricultural Topsoil and Growing Perennial Ryegrass (Lolium perenne L.) Enhanced the Rehabilitation of Metal/loids Enriched Iron Ore Mine Tailings

Revegetating iron-ore mine tailings is difficult due to their poor physicochemical and microbial properties. This experiment aimed to improve tailings properties for better plant growth and rhizosphere activities. First, a pot experiment was conducted to assess the influence of topsoil amendment on the remediation of tailings collected from two sites (coded A and B) in Western Australia to promote the growth of perennial ryegrass (Lolium perenne L. cv Ausvic). Each pot was filled with pre-defined ratios of topsoil to mine tailings (0, 10, 20, 30, 50 and 100% w/w). Perennial ryegrass was harvested 60 days after sowing and analysed for plant growth, root morphological characteristics and metal uptake by shoots. Second, a study on biological attributes and an incubation study over 84 days were carried out. The addition of topsoil significantly decreased pH, but EC and total organic carbon (TOC) increased with an increased proportion of topsoil. Total concentrations of As, Co, Cr, Cu, Ni, Pb, Zn, Fe and Mn decreased with an increased ratio of topsoil in growth medium. The highest root dry biomass was observed in the treatments with 30% and 50% topsoil addition to tailings, whereas shoot dry biomass only increased with 50% topsoil. Total root length increased significantly with 50% topsoil addition to site A tailings. A significant increase in microbial biomass carbon (MBC) was found with 50% addition of topsoil compared with the control. Microbial quotient (MBC/TOC) decreased significantly with the addition of topsoil to both types of tailings. Metal contents in perennial ryegrass shoots decreased with the increasing rate of topsoil, but perennial ryegrass was an effective phytoextractor of Cu, Zn and Mn. Further, the incubation study revealed that 50% topsoil application increased cumulative respiration emissions in both A and B tailings after 42 days. Iron ore mine tailings can be improved in terms of physicochemical and biological attributes by adding topsoil. However, further investigation should be carried out to determine the speciation of metal/loids in amended iron ore tailings.

Case studies of assessment of human health risks after the dam failures of the Córrego do Feijão Mine and Fundão in Brazil

ABSTRACT In recent years, there has been an increase in environmental catastrophes involving mining dam failures. This study assessed the potential risks of iron ore tailings in riparian soils to human health after the worst dam collapses recorded in Brazil: from Córrego do Feijão Mine-CFM and Fundão. Chemical monitoring data from the three-year time interval since the collapses were used to estimate human risk indexes for trace elements such as arsenic, cadmium, chromium, mercury, nickel, lead, and zinc. In both case studies, the adult group indicated a propensity for the development of non-carcinogenic diseases through ingestion, inhalation and dermal pathways for all contaminated areas. Overall, children showed an exacerbated sensitivity to possible cancerous and non-cancerous effects, especially in the areas surrounding the dams and in Barra Longa, São José do Goiabal, Córrego Novo, Veneza, Periquito, Governador Valadares, Tumiritinga, Conselheiro Pena, Honório Fraga and Linhares (from the Fundão dam) and in all study areas from the CFM dam. These assessments demonstrate that in regions with mining activities, the cumulative effects of trace elements over time are harmful and expected. Therefore, there is a need for greater supervision by competent government bodies of conservation practices that enable environmental recovery or mitigation of their impacts, ensuring appropriate health and well-being conditions for local residents and workers.

Influence of key design variables on dynamic material properties of iron tailing porous concrete under impact loading

Iron tailing porous concrete (ITPC) is a new foamed concrete material that using iron ore tailing powder to partially replace the cement. Previous investigations on ITPC primarily focused on its mechanical properties under static loads or low strain rate conditions, leaving a significant gap in its impact resistance performance at high strain rates. This study employed the split Hopkinson pressure bar (SHPB) to test ITPC specimens under impact loading with strain rate around 120 s−1. Density, water-binder (W/B) ratio, iron tailing powder content, polypropylene fiber length and content were taken as key design variables to prepare the ITPC specimens with different mix ratios and study their effects on the dynamic material properties of ITPC. Specifically, the failure modes, stress-strain relations, elastic moduli, compressive strengths and energy dissipation densities of the ITPC specimens with various design variables were recorded and compared. The test results indicate that the material density, fiber length and content have strong influences on the impact failure modes of ITPC. The elastic modulus, compressive strength and energy dissipation density of ITPC exhibit exponential growth with the material density. These parameters, however, show an initial growth followed by a decrease with the rising W/B ratio, fiber length and fiber content, and they reach the peak values at around 0.70, 9 mm and 2.0%, respectively. Moreover, the iron tailing powder content of 25% is recommended for ITPC for maintaining good impact resistance.

Potential toxicity of iron ore tailings after the overflow of a mining dam in Nova Lima (Minas Gerais State, Brazil)

In January 2022, the Pau Branco Mine dam in Nova Lima (MG), under the responsibility of Vallourec, overflowed after intense rainfall and iron ore tailings impacted surrounding soils and aquatic ecosystems. These tailings can alter the natural composition of soils and rivers, poising risks on soil biota. This study consists of a preliminary evaluation of potential toxicity of terrigenous materials impacted by tailings from the Pau Branco Mine, based on acute bioassays with earthworms (Eisenia andrei) and germination tests with lettuce (Lactuca sativa). The physical and chemical characterization and determination of toxic metals in the samples supported the interpretation of the ecotoxicological data. The results indicated that the tailing deposition induced the increase in particle density, due to the increase in iron concentrations in the samples. As a consequence, the water holding capacity (WHC) of the materials and organic matter concentrations were dramatically reduced. Given that the mining tailings exhibit fine texture, their depositions on soils increased the percentage of fines particles (silt) in the samples. Metal determination revealed geochemical anomalies for nickel, copper and chromium, whose concentrations exceeded the threshold limits defined by Brazilian law for soil and aquatic sediment quality. The bioassays with earthworms showed no significant earthworm mortality, indicating low acute toxicity. However, earthworm biomass was significantly reduced, suggesting that they were submitted to some stress induced by the exposure to contaminants and/or by the reduction of the organic matter contents (food scarcity) and WHC (water scarcity). The bioassays with lettuce showed no significant effects on germination levels. However, the seedling biomass was significantly reduced due, possibly, to the reduction of WHC and especially due to the increase of fines particles in the samples, which tends to inhibit the establishment of the root systems.

Novel solar-induced wastewater purification materials originated from ore tailing solid waste

Ore tailings (OT) are solid waste produced as a by-product of the mining industry, posing serious environmental challenges. Ensuring the low-carbon and environmentally friendly development of mineral raw materials, enhancing the reclamation, reuse and recycling rate of raw materials in the full lifecycle, presents a significant challenge. To achieve high-value utilization of OT and solve the problem of clean water supply, a novel solar evaporation wastewater purification material was developed using modified ore tailing/acrylate composite photothermal coating. The photothermal functional modified ore tailings (OT@PDA@CB) were fabricated by grafting carbon black (CB) and polydopamine (PDA) onto the OT surface through the physical adhesion of active chemical groups, synergistically enhancing broadband light absorption ability of OT@PDA@CB/acrylate coating. UV–Vis-NIR spectra showed increased absorption in visible and near-infrared (NIR) light. Surface temperature of OT@PDA@CB/acrylate coating under 1200 W/m−2 illumination increased to 65.6 °C compared with 52.6 °C of OT/acrylate coating due to increased light absorption, resulting in an evaporation rate of 0.89 kg·m−2·h−1 within 1 h. The solar evaporation efficiency for OT@PDA@CB evaporator was 48.3%, which was 192.7% higher than that in blank acrylate sample. The obtained OT@PDA@CB/acrylate composite photothermal coating demonstrated versatile abilities for desalination, heavy-metal purification and organic contaminant removal. This work offers a straightforward approach for high-value utilization of inexpensive mineral solid wastes and green solar-induced wastewater purification technique.

Ex-post impact assessment on a large environmental disaster

Impact assessments following environmental disasters must be quick and in accessible language so that decision-makers and affected populations are aware of the main impacts and can target recovery measures. After the collapse of the Fundão dam (Minas Gerais, Brazil) in November 2015, an extensive monitoring program was implemented to understand the aquatic environmental situation and associated biodiversity status after the spill of the iron ore tailings in a large and highly populated watershed, that reached the Atlantic Ocean along the southeast Brazilian coast. A monitoring programme faced several challenges, including the large volume of data to be analysed, which difficult an objective environmental diagnosis and the communication between technical teams and decision makers. In this context, an impact matrix was proposed as a tool for assessing the environmental proxy results and summarizing the results obtained. The proposed Impact Matrix is an interaction matrix adaptation which consists of quantifying the impacts using pre-defined criteria and scores. Expert panels assessed the link between environmental measures and objectives by scoring the specific criteria. As an interaction matrix, the impact matrix is made up of two intersecting axes: the identified impact and the affected environmental compartments (whether abiotic or biotic). The final impact matrix is reached by summing up the score for the criteria on each of the identified intersections. The impact matrix is a supervised approach focused on provide relatively simple tool to apply and, when carried out periodically in parallel with a monitoring programme, it makes it possible to observe temporal trends in the evolution of the environment after the event causing the impact. The impact matrix can also serve as feedback to the monitoring programme itself, when used in an adaptive management approach.

Hydraulic Characteristics of Silt-Sized Iron Ore Tailings

Hydraulic Characteristics of Silt-Sized Iron Ore Tailings

Impacts of mining disasters on the ambulatory care of the Brazilian national health system: the cases of Mariana and Brumadinho/Brazil

BackgroundDisasters are events that bring with them effects that contribute to the disruption of the normality of a population and thus highlight the vulnerabilities of the health system. In Mariana and Brumadinho, the collapse of the dam of ore tailings brought with it several impacts that were felt in the short term and will be felt in the medium and long term. And that by being intensely intertwined with issues of economic and productive nature, has as its meaning an uninterrupted result of its activities.MethodsThrough the DATASUS database, two specific variables were chosen to perform the analysis: the approved amount and the approved value. For this research, a methodological device, the segmented regression line, was used to observe the influences that the disasters that occurred in Mariana and Brumadinho had on the ambulatory health systems.ResultsThe results of the segmented regression line show that, with Mariana, the amount approved continued to grow throughout the period, which shows that there was no change because of the disaster. There was a reduction in spending. In Brumadinho, regarding the amount approved, there was an upward trend in the disaster’s month, which did not change immediately afterwards, and regarding expenditure, the growth pattern was maintained in all three periods. Corroborating this data, the relative and absolute base elements show an increase in the amount approved and in the number of services provided at various posts compared with Minas Gerais.ConclusionsBased on the findings, it was possible to understand that although disasters exert an influence that may have some effect on the health system, the lack of significance sometimes cannot be interpreted as a lack of impact on the disaster. The segmented regression line outlines some effects that are not conclusive but indicative of a numerical interpretation and a trend interpretation.

Development of sacrificial anode from Al, Mg, and Ti from iron Ore tailings

ABSTRACT This investigation used aluminium, magnesium, iron ore tailings, and low-carbon steel. Iron ore tailings (5–30 wt% Mg and 50 μm in size) in an aluminium matrix formed the anode. In 0.5 M NaCl solution, the weight loss, corrosion rate, and electrochemical properties were measured. Samples A to E have corrosion rates of 0.43, 0.28, 0.36, 0.08, and 0.11 mm/yr, respectively. SEM/EDS examination revealed the presence of elemental Al, Mg, O, and Si in the anode. The XRD patterns indicate intermetallic compounds such as iron nitride (Fe3N), aluminium silver (Ag-Al), and manganese zirconium (Mn2Zr). In samples A, B, and C, Al and Mg formed a protective coating on the anode, while C and Si reduced passivation and released electrons to protect the steel. IOTs and Mg in the aluminium matrix improve the anodic corrosion resistance. The observed improvements in corrosion resistance highlight the potential of these sacrificial anodes for practical applications in corrosion protection systems.

Biomassa e demanda hídrica do capim mombaça em solo afetado pelo rompimento da Barragem do Fundão

ABSTRACT The collapse of the Fundão Dam in Mariana, MG, in 2015 introduced the challenge of using Technosol, a soil type formed by deposition of iron mining waste along the Doce River banks, for agricultural purposes. This study aimed to determine the optimal water depth for enhancing production of tropical forage, Megathyrsus maximus cv. Mombasa, when grown on iron ore tailings. Additionally, it sought to establish a crop coefficient applicable to the edaphoclimatic conditions of Viçosa, MG, Brazil. The experiment was conducted throughout the summer, fall, and winter of 2022, employing 21 drainage lysimeters. A completely randomized experimental design was adopted, featuring six treatment groups (plants in Technosol receiving water depths ranging from 20 to 120% of the crop’s evapotranspiration, as derived from the control treatment), along with a control group (plants in Latosol with a depth of 100%), each with three repetitions. Our findings showed that irrigation must replace 40% of the crop evapotranspiration. Moreover, cultivating in Technosol resulted in a reduction of productive capacity by 37.39% during the summer/fall and fall seasons. For Mombasa grass grown in Oxisol, crop coefficients of 1.2 during the summer and 1.5 during the fall and winter are advised.

Evaluation of the effects of different hydroxamates and a sulfosuccinamate in the direct flotation of iron ore tailings

Evaluation of the effects of different hydroxamates and a sulfosuccinamate in the direct flotation of iron ore tailings

Effect of Iron Ore Tailings and High Magnesium Nickel Slag on Flyash - Ggbs Based Geopolymer Concrete (GPC)

Abstract: The cement industry is a major producer of carbon dioxide (CO2), a powerful greenhouse gas which contaminate the environment by emitting massive volumes of CO2. The building sector contributes both directly and indirectly to environmental degradation, natural resource depletion, and global warming. From a sustainability standpoint, it is critical that cement manufacturing be reduced. Geopolymer concrete (GPC) is a new material that does not require portland cement as a binder, instead, materials rich in Silicon (Si) and Aluminum (Al), such as Flyash (FA) and Ground granulated blast furnace slag (GGBS) are activated by alkaline liquids to produce the binder. The use of iron ore tailings (IOT) in place of traditional aggregates in concrete has been discovered to be feasible. Concrete made using IOT aggregate performed well with respect to strength and durable studies. GPC mix of 12M was prepared using FA, GGBS, aggregates, alkaline alkali activators such as Sodium hydroxide (NaOH) and Sodium silicate (Na2SiO3). A study on using iron ore tailings (IOT) in replacement of fine aggregates in percentages of 20, 30, 40 and 50 are studied in GPC. After achieving optimum strength in above mix then high magnesium nickel slag (HMNS) was replaced with varying percentages 5, 7.5, 10 and 12.5. As alkaline activators with 12M NaOH and Na2SiO3 solutions are used with a ratio of 2.5. Mechanical properties such as Compressive, Split tensile and Flexural strength are evaluated to determine the influence of IOT and HMNS replacement in GPC.

Hybrid Effect of Basalt and Polyacrylonitrile Fibers on Physico-Mechanical Properties of Tailing Mortar

In this study, 50% iron ore tailings (IOTs) were used to prepare the cemented mortar at low economic costs and with great environmental benefits. Basalt fiber (BF) and polyacrylonitrile fiber (PANF) were added to the tailing mortar to improve the comprehensive performance of tailing mortars, including BF (0~0.5%), PANF (0~0.05%) and the combination of them. The results show that the addition of BF and PANF can significantly improve the ultrasonic velocity, uniaxial compressive strength (UCS), split-tensile strength (STS), flexural strength (FS) and toughness of the tailing mortar. A novel finding is that the enhancement of hybrid fibers is much better than single fiber, and the best hybrid fiber combination is B0.25P0.05 (0.25 wt% BF and 0.05 wt% PANF), because this combination not only causes the most considerable increase in strength but also possesses great cost-effectiveness. Compared to the B0P0 group without fibers, the maximum increments of B0.25P0.05 in UCS, STS and FS are 45.74%, 52.33% and 15.65%, respectively. It is evidenced that the improvement in STS is the largest because the fibers have good cracking resistance and bridging effect in the tailing mortar. The scanning electron microscope (SEM) further confirms that too many hybrid fibers will agglomerate and produce more voids, which is harmful to the development of the internal structure. Beyond B0.25P0.05, the hydration products are also reduced due to the decrease in nucleation sites, observed by combining X-ray diffraction (XRD) tests. Therefore, it is suggested that the hybrid fibers containing 0.25% BF and 0.05% PANF should be used in this tailing mortar.

Novel insights into the effect of cone structure on the classification performance of dual-cone hydrocyclones

The classification process in hydrocyclones is affected by many factors, with the cone angle being recognized as a critical parameter determining the classification performance. In the context of recycling iron ore tailings, this paper primarily focuses on the influence of cone angles and their combination sequences on the classification performance of quartz particles within a dual-cone hydrocyclone through numerical simulations. The upper and lower cone angles were configured in 16 combinations to assess their respective impacts on classification. The results indicate that the upper cone angle primarily governs the pressure drop and tangential velocity, thereby controlling the centrifugal intensity and cut sharpness. Furthermore, the lower cone angle plays a pivotal role in determining axial velocity and particle enrichment ratio in the lower cone, thus influencing the cut size and grade efficiency. These findings should provide valuable guidance for the design and application of compound cone hydrocyclones, depending on specific requirements.

Preparation of Mn2O3/Fe2O3 composite cathode material for zinc ion batteries from the reduction leaching solution of manganese ore tailing

The high-value utilization of tailings is crucial for saving limited resources and supporting the sustainable development of society. In the present work, a Mn2O3/Fe2O3 composite is prepared from manganese ore tailing through reduction leaching and thermal decomposition methods. Further, the zinc storage performance of the Mn2O3/Fe2O3 composite for zinc ion batteries (ZIBs) is explored. The Mn2O3/Fe2O3 composite maintains a specific capacity of 224.8 mA h g−1 after 300 cycles at 500 mA g−1, suggesting its potential applications in ZIBs. CV and GITT analysis reveal that the Mn2O3/Fe2O3 composite has an obvious pseudocapacitive behavior during the charge/discharge process, and the Zn2+ diffusion coefficient ranges in the orders of 10−14-10−12 cm2 s−1. The charge/discharge mechanism of the Mn2O3/Fe2O3 composite is also explored using ex-situ XRD and XPS measurements. The work provides a new avenue for the high-value use of manganese ore tailing in the electrochemical energy storage field.

The reinforcement mechanism of basalt and polypropylene fibers on the strength, toughness and crack resistance of tailing mortar

The replacement of river sand in the mortar by using iron ore tailings (IOT) can not only turn waste tailings into wealth but also protect the environment. In order to further improve the physico-mechanical properties and cracking resistance of cement mortar with 50% IOT, a series of experiments were conducted by adding different contents of basalt fiber (BF) and polyacrylonitrile fiber (PANF). The consistency decreases significantly with increasing the BF and PANF contents. A proper content of fibers can be evenly distributed in the mortar and thus reduce the porosity. However, excessive fibers will aggregate and increase the porosity. In addition, it has been validated that fibers can significantly improve the strength and prevent the brittle cracking. With increasing fibers, the density, ultrasonic velocity, and mechanical strength of hardened fiber-reinforced mortar first increase and then decrease. The best adding contents of BF and PANF are 1.0% and 0.08%, respectively. The rigid BF (length=6 mm) can significantly increase the uniaxial compressive strength (UCS) by 32.57% due to its good shear-resistance ability, however, the flexible PANF with the length of 12 mm is better to improve the split-tensile strength (STS) and flexural strength (FS) by 22.63% and 17.43% due to the formation of three-dimensional network structure in the specimens. In addition, the scanning electron microscopy (SEM) and X-ray diffraction (XRD) tests show that excessive fibers will agglomerate and produce a certain amount of air, while a proper adding content of fibers provides more attachment points for hydration products to promote the hydration reaction. It is suggested to adopt the best adding content and choose proper fiber types according to the loading form of construction structure with tailing cement mortar in the fields.

The Mechanical Properties and Microstructure of Tailing Recycled Aggregate Concrete.

The aim of this study was to develop sustainable concrete by recycling concrete aggregates from steel waste and construction waste (iron ore tailings (IOTs) and recycled coarse aggregates (RCAs)) to replace silica sand and natural coarse aggregates. In experimental testing, the compressive strength, peak strain, elastic modulus, energy dissipated under compression, and compressive stress-strain curve were analyzed. Microscopically, scanning electron microscopy and energy-dispersive spectrometry were employed to investigate the microstructural characteristics of the interfacial transition zone (ITZ), and the results were compared with the ITZs of natural aggregate concrete and recycled aggregate concrete (RAC). In addition, the pore structure of concrete was determined by nuclear magnetic resonance. The results revealed that an appropriate IOT content can improve the ITZ and compactness of RAC, as well as optimize the mechanical and deformation properties of RAC. However, due to the presence of a smaller number of microcracks on the surface of IOT particles, excessive IOTs could reduce the integrity of the matrix structure and weaken the strength of concrete. According to the research, replacing silica sand with 30% IOTs led to a reduction in the porosity and microcracking which resulted in a much denser microstructure.

Food web structure of fish communities of Doce River, 5years after the Fundão dam failure.

The rupture of the Fundão dam is considered the largest mining failure in history, which had a particularly detrimental impact on fish populations, as the mud from the ore tailings significantly altered the water quality and habitat of Doce River basin. This study aimed to assess the trophic structure of fish communities in areas impacted and not impacted by the dam rupture in the Doce River basin. To evaluate the food web structure, community-wide trophic niche, and trophic positions of fish, stable isotopes of carbon (δ13C) and nitrogen (δ15N) were utilized across ten sites (seven impacted and three control). In general, fish appeared to assimilate resources such as invertebrates, algae, and periphyton, although the importance of each resource varied among sites. The site closest to the dam rupture exhibited a more simplified trophic structure compared to the control sites and those nearer the river mouth. In this site, most fish species occupied a similar trophic position. Trophic niches also exhibited the greatest dissimilarity between the site closest to the dam failure and those farther away from it, with an expansion of trophic niche breadth observed with an increase in the distance from the dam rupture. Our study provided valuable insights into the trophic structure of fish communities within the Doce River basin, shedding light on the trophic ecology of the 59 fish species investigated. We also emphasize the importance of our study for future assessments of ore tailings dam failure disasters and evaluating the effectiveness of mitigation measures for Doce River basin recovery.