Tailings Dam Research Articles

Compressibility and small strain stiffness characteristics of silt-hematite mixtures

Iron mining waste is disposed of near mines and forms iron ore (hematite) tailings dams. Furthermore, the distinctive characteristics of hematite particles can affect the geotechnical properties of soil. This study aimed to experimentally examine the compressibility and small-strain stiffness of silt-hematite mixtures. Silt-hematite mixtures were prepared in an oedometer cell at a fixed relative density with different hematite contents (0% to 100% in weight). Vertical displacements and loads were measured with the oedometer, and shear and compression waves were measured using bender and piezo-disk elements, respectively. The results showed that the void ratio and compressibility increased, while the constrained modulus decreased with increasing hematite content as hematite formed porous aggregate owing to high van der Waals forces. The elastic wave velocities (Vs and Vp) and small-strain moduli (Gmax and Mmax) increased with increasing hematite content owing to hematite's high stiffness and coordination number. Furthermore, the elastic wave velocities of high hematite-content specimens were practically constant at low-stress levels (<20 kPa), because of the van der Waals forces being greater than the skeletal forces. This study suggests that the geotechnical properties of hematite-containing soils, hematite-coated soils, and iron ore tailings soils can be evaluated by the hematite ratio.

Circular use of fine-grained tailings to underground mine wind walls

Mining activities tend to generate various waste including tailings, waste water and waste rock. Efficient management and disposal of these waste materials are critical to minimize their environmental impact and ensure the sustainable operation of mining activities. A huge number of tailings are produced all around the world each year. Generally, part of the tailings is used for underground backfilling and another part is discharged to the tailings dam. The former can provide underground support while the latter tends to cause some environmental problems because the tailings are generally mixed with some chemicals. Regarding this, enhancing the circular use of tailings is crucial to guarantee the sustainable mining engineering. In this study, the feasibility of using fine-grained tailings to make non-burning hollow bricks for underground windbreaks is investigated. A two-stage experiment was implemented where the first stage experiment indicated the threshold of water content, the ratio of cement and tailings and the ratio of fine-grained and rod-mill tailings. In addition, it can be indicated that the addition of polyethylene fibers would increase the compressive strength of hollow bricks in some extent. The second-stage experiment was conducted with no rod-mill tailing added and it can be found that when the ratio of cement and tailings is equal or higher than 1:6, fiber content is more significant in improving brick strength but when this value is lower, the ratio of cement is more important than fiber factors. When the ratio of cement and fine-grained tailings is 1:8 with 0.5 g/kg and 12 mm polypropylene fiber added, the hollow brick is capable of achieving strength of 1.4 MPa for 28 days curation with the price of 0.50 RMB/block. This proportioning scheme is the least expensive while meeting the strength of the windbreak wall for the Fan Kou lead–zinc mine. Finally, it can be indicated that the usage of fine-grained tailings to make underground windbreak wall is feasible and thus provide a new scenario to circular usage of tailings. In addition, other proportioning schemes proposed in this study perhaps can meet more engineering requirements so as to provide more alternatives for circular use of tailings.

Centrifuge and Numerical Modeling of Liquefied Flow and Nonliquefied Slide Failures of Tailings Dams

Centrifuge and Numerical Modeling of Liquefied Flow and Nonliquefied Slide Failures of Tailings Dams

Notifications of work-related injuries and diseases: an observational study on a mining disaster

IntroductionAccidents at work are events that endanger the health and life of workers. They are considered a public health problem, being the object of studies and actions in the Brazilian health system. The collapsed of the ore tailings dam in the municipality of Brumadinho, Brazil, in January 2019, shocked the world due to the proportion of environmental and human damage caused. In this context, concern for the health of workers gained prominence. This paper evaluated the impact of the collapse of the mining tailings dam in Brumadinho, on notifications of occupational health problems before and after the disaster.MethodsAn observational, longitudinal and retrospective study, of the time series type with a statistical approach was carried out on notifications of work-related injuries and diseases, available in the local database of the Notifiable Diseases Information System between January 2017 and December 2021.ResultsDuring the study period, 520 notifications of work-related injuries and conditions were registered. Of this total, 67.3% were serious work accidents, 26.0% mental disorders, 12.3% accidents with biological material and 2.9% repetitive strain injuries/musculoskeletal disorders, occupational dermatoses and induced hearing loss by noise. Occurrences were more frequent in 2019, the year in which the mining disaster occurred, recording 65.2% of total notifications. Regarding the volume of notifications after the disaster, there was a statistically significant reduction (p < 0.001) for accidents with biological material; significant increase for severe work accident and mental disorder. The average time between the occurrence of the injury and the notification showed a statistically significant reduction for accidents involving biological material (p = 0.001) and a significant increase for serious accidents at work (p = 0.016).ConclusionsIt was demonstrated that there were changes in the number of notifications when comparing the period before and after the mining disaster, with a consequent impact on the health of workers, which may persist over the years.

Plant growth-promoting and heavy metal-resistant Priestia and Bacillus strains associated with pioneer plants from mine tailings.

Open mine tailings dams are extreme artificial environments containing sizeable potentially toxic elements (PTEs), including heavy metals (HMs), transition metals, and metalloids. Furthermore, these tailings have nutritional deficiencies, including assimilable phosphorus sources, organic carbon, and combined nitrogen, preventing plant colonization. Bacteria, that colonize these environments, have mechanisms to tolerate the selective pressures of PTEs. In this work, several Priestia megaterium (formerly Bacillus megaterium), Bacillus mojavensis, and Bacillus subtilis strains were isolated from bulk tailings, anthills, rhizosphere, and endosphere of pioneer plants from abandoned mine tailings in Zacatecas, Mexico. Bacillus spp. tolerated moderate HMs concentrations, produced siderophores and indole-3-acetic acid (IAA), solubilized phosphates, and reduced acetylene in the presence of HMs. The strains harbored different PIB-type ATPase genes encoding for efflux pumps and Cation Diffusion Facilitator (CDF) genes. Moreover, nifH and nifD nitrogenase genes were detected in P. megaterium and B. mojavensis genomic DNA. They showed similarity with sequences of the beta-Proteobacteria species, which may represent likely horizontal transfer events. These Bacillus species precede the colonization of mine tailings by plants. Their phenotypic and genotypic features could be essential in the natural recovery of the sites by reducing the oxidative stress of HMs, fixing nitrogen, solubilizing phosphate, and accumulating organic carbon. These traits of the strains reflect the adaptations of Bacillus species to the mine tailings environment and could contribute to the success of phytoremediation efforts.

Experimental study on solidification of uranium tailings by microbial grouting combined with electroosmosis

The present microbial reinforcement of rock and soil exhibits limitations, such as uneven reinforcement effectiveness and low calcium carbonate generation rate, resulting in limited solidification strength. This study introduces electroosmosis as a standard microbial grouting reinforcement technique and investigates its solidification effects on microbial-reinforced uranium tailings. The most effective electroosmosis effect on uranium tailings occurs under a potential gradient of 1.25 V/cm. The findings indicate that a weak electric field can effectively promote microbial growth and biological activity and accelerate bacterial metabolism. The largest calcium carbonate production occurred under the gradient of 0.5 V/cm, featuring a good crystal combination and the best cementation effect. Staged electroosmosis and electrode conversion efficiently drive the migration of anions and cations. Under electroosmosis, the cohesion of uranium tailings reinforced by microorganisms increased by 37.3% and 64.8% compared to those reinforced by common microorganisms and undisturbed uranium tailings, respectively. The internal friction angle is also improved, significantly enhancing the uniformity of reinforcement and a denser and stronger microscopic structure. This research demonstrates that MICP technology enhances the solidification effects and uniformity of uranium tailings, providing a novel approach to maintaining the safety and stability of uranium tailings dams.

Safety and stability evaluation of uranium tailings dam considering radioactive deviation degree

Safety and stability evaluation of uranium tailings dam considering radioactive deviation degree

Groundwater Circulation in the Shallow Crystalline Aquifer of Tharisa Mine, South Africa: Evidence from Environmental Isotopes and Near-Surface Geophysics

For underground mining, efficient groundwater management is one of the critical mining economics components. The region of interest, known as Tharisa Mine, is situated on the western limb of the Bushveld Igneous Complex, which is home to South Africa’s premier platinum-group metal resources. This work aimed to provide the findings from the investigation and imaging of the near-subsurface hydrogeological architecture in a shallow profile using stable isotopes of water (18O and 2H) and radioactive water isotopes (3H). Regarding isotope data, 18O varied from −3.5 to 1.5‰; 2H from −24 to 4.7‰; and 3H from 2.0 to 3.4 T.U. Utilizing combined geophysical techniques, the results were verified. Additionally, the geophysical methods, including seismic refraction tomography, multichannel analysis of surface waves, electrical resistivity tomography, and magnetics, helped identify the fluid’s pathways and lineaments during migration to verify the isotope results. The groundwater inflow volumes into the open pit were initially determined by integrating the following findings: the delineation of fracture systems/zones and fluid migration pathways; mining activities enhance the storage and transmission ability of the aquifer; and the main sources of water in the mine include mixing of surface and deep water sources, recycling of water possibly via lineaments, and tailings dam seepages.

Scientific Research Support for the Construction and Operation of Inwashed Tailing Dumps at Operating Sites

Accidents at mining enterprises, including tailing dumps, pose significant threats to human lives, structures, and the environment. This study focuses on designing, constructing, and operating tailing dumps in Siberia’s northern region. To ensure safety and minimize environmental impacts, comprehensive scientific monitoring and research were conducted at all stages, including design, construction, operation, and disposal. The aim was to create a uniform mass within the dam body, requiring understanding of the tailing structure and technological characteristics during placement. Parameters like particle size, distribution, density, and moisture content were considered to assess the physical and geometric properties of the tailings. Estimated monitoring was introduced as a permanent model to quickly assess the stability of hydrotechnical constructions. This involved monitoring changes in exploitation properties, structure height, beach length, and water levels. A controlled inwashing technology for subsequent dam layers was developed. Complex research facilitated the formulation of an estimated monitoring methodology and an algorithm for tailing dam formation. Practical application demonstrated high reliability and confirmed load-bearing capacity, allowing for the forecast of dam stability and safe execution. Findings led to alterations in work techniques, ensuring safe and efficient operation of tailing dams.

Probabilistic Analysis of Floods from Tailings Dam Failures: A Method to Analyze the Impact of Rheological Parameters on the HEC-RAS Bingham and Herschel-Bulkley Models

The difficulty in determining the rheological characteristics of tailings inside reservoirs as well as their intrinsic variability adds uncertainty to tailings dam failures in flood studies. Uncertainty propagation in non-Newtonian hydrodynamic models stands as a great scientific challenge. This article explores the sensibility of tailings dam breach flood mapping to rheological parameters in Bingham and Herschel-Bulkley (H-B) models. The developed approach was based on the probabilistic Latin Hypercube Sampling of rheological parameters. It was automated to propagate uncertainty throughout multiple hydrodynamic simulations using the HEC-RAS v.6.1 software. Rheological parameter ranges and distributions were based on a broad bibliographic review. Bingham models were revealed to be more sensitive than H-B in terms of simulated min-max area values: for Bingham, flood areas, maximum depths, and arrival times varied by 17.9%, 9.3%, and 8.2%, respectively; for H-B, variations were 25.7%, 5.1%, and 3.9%. However, Bingham was less sensitive in terms of hydrodynamically associated probability: high probability ratios were related to a small range of simulated areas in Bingham, while H-B presented great variability. Finally, for each model, the parameters that affect uncertainty the most were identified, reinforcing the importance of determining them properly. Furthermore, the identified parameter ranges for both models should be valuable for defining variable value boundaries for flood sensitivity tests on specific tailings materials for other case studies. The automated algorithm can be used or adapted for specific tests with other hydrodynamic simulations.

Effect of chemical environment on copper tailings reinforced by microbially induced carbonate precipitation

The accumulation of large amounts of tailings produced in the beneficiation process of ores is one of the main challenges for mining industry related to their retention in tailings ponds and the potential hazard of tailings dams’ failure. To enhance stability of tailings dams, microbially induced carbonate precipitation (MICP) has emerged as a novel technique for tailings treatment. However, the intricate chemical environment within tailings ponds affects the growth of microorganisms and can adversely impact the efficiency and effectiveness of MICP. This study investigates for the first time the factors that influence the growth of Sporosarcina pasteurii in a copper tailings pond characterized by weak acidity and the presence of copper ions. The adverse effects of the chemical environment in copper tailings ponds on MICP are investigated through mechanical tests and microscopic analyses on four groups of MICP-reinforced copper tailings. The results revealed that copper ions inhibited the growth of bacteria, while pH had an insignificant effect on bacteria. Hence, copper ions are identified as the main factor that weakens the reinforcing effect of MICP on copper tailings. Even though the weakly acidic environment has been shown to have a minor impact on the performance of MICP-reinforced copper tailings, maintaining the acid resistance of the reinforced tailings is crucial for ensuring long-term reinforcement effectiveness. It was also found that increasing the concentration of the bacterial solution and applying it in multiple injections, while controlling the pH of the cementation solution, could enhance the survival rate and activity of bacteria and improve the carbonate sedimentation environment. This would strengthen the reinforcing effect of MICP. The results demonstrated that MICP has promising potential for tailings treatment, but it is essential to address the adverse effects of the chemical environment in tailings ponds. The findings from this study provide valuable reference data for subsequent field experiments and engineering practices and facilitate the application of biomineralization in tailings ponds.

Pollution Level, Ecological Risk Assessment and Vertical Distribution Pattern Analysis of Heavy Metals in the Tailings Dam of an Abandon Lead–Zinc Mine

Tailings dams in mining areas frequently experience the phenomenon of haphazard dumping and stacking of a large amount of tailings waste. Under the influence of surface runoff and groundwater infiltration, heavy metals from tailings waste can migrate to the surrounding areas and underground soil, resulting in extensive heavy metal pollution. To analyze the pollution level and ecological risk of heavy metals in an abandoned lead–zinc mine tailings dam, this study first employed X-ray fluorescence analysis to determine the vertical distribution patterns of heavy metals with depth. Then, the pollution levels of heavy metals were analyzed based on the Nemerow comprehensive pollution index and geoaccumulation index. Subsequently, the ecological risk of heavy metal pollution was further assessed using the potential ecological risk (PER) index. Finally, the sources and potential hazards of heavy metal pollution were investigated. The results reveal that (1) heavy metal pollutants are identified as lead (Pb), zinc (Zn), copper (Cu) and arsenic (As), displaying enrichment at the interface layer between the reclaimed zone and tailings layer with the highest concentrations; (2) the pollution degrees in each zone follow the order of interface layer &gt; tailings layer &gt; deep zone &gt; reclaimed zone, and the pollution levels for the four heavy metals in decreasing order are Pb &gt; Zn &gt; As &gt; Cu; (3) after considering the toxic effects of heavy metals, the potential ecological risk in each zone remains consistent with the ranking of pollution levels, and the contribution of the four heavy metals to PER changes to Pb &gt; As &gt; Zn &gt; Cu, corresponding average Eri values of 913.928, 416.900, 96.462 and 47.998, respectively; (4) ecological risk of heavy metals originates from lead–zinc ore extraction, and heavy metal pollution poses potential risks to public water security and surrounding ecological resources.

Development of an agent-based model to improve emergency planning for floods and dam failures

Abstract The Life Safety Model (LSM) is an agent-based model which assists with emergency planning and risk assessments for floods and dam failures by providing estimates of fatalities and evacuation times. The LSM represents the interactions of agents (i.e. people, vehicles, and buildings) with the floodwater. The LSM helps to increase the accuracy of estimates of loss of life and evacuation times for these events by taking into account a number of parameters which are not described in empirical models, such as the people's characteristics (e.g. age and gender), building construction types, and the road network. The LSM has been applied to three historic flood-related disasters: the 1953 coastal floods, in the UK; the 1959 Malpasset Dam failure, in France; the 2019 Brumadinho tailings dam disaster, in Brazil. These illustrate how the LSM has been verified and improvements to evacuation routes, early warnings, and the refuge locations could have reduced the number of fatalities. The value of using the LSM is not to calculate the ‘exact’ number of flood deaths or evacuation times, but to assess if emergency management interventions can significantly reduce them. The LSM can also be used to assess whether the societal risk posed by dams and flood defences is ‘acceptable’.

Drained instability of coarse oil sand tailings

Lateral stress relief and effective stress reduction have been recognised as the culprits in flow failures of several mine tailings dams. This research examines the instability of coarse oil sand tailings (CSTs) subjected to such a stress path through a series of monotonic direct simple shear tests. To investigate the impact of tailings fabric, laboratory specimens were reconstituted by moist-tamping, air pluviation and slurry deposition techniques. Loose, medium-dense and dense specimens were prepared and consolidated to target vertical and initial shear stresses. The vertical stress was subsequently unloaded while maintaining a constant initial shear stress under a drained condition. The occurrence of instability coincided with the volumetric collapse of the specimens followed by a sharp rise in shear strain. The effects of consolidation stress, bitumen, void ratio, initial shear stress and unloading rate on the drained instability of CST specimens were also investigated.

Unlocking the potential of microbes: biocementation technology for mine tailings restoration - a comprehensive review.

Mine tailings contain finer particles, crushed rocks, dugout-soil, water, and organic and inorganic metals or metalloids, including heavy metals and radionuclides, which are dumped as waste or non-economic by-products generated during mining and mineral processing. These abundant and untreated materials seriously threaten the environment, human health, and biodiversity because of the presence of heavy metals, radionuclides, and associated primary and secondary toxic components, including the risk of tailings dam failures. Biocementation technology, which involves the use of mining microbes to secrete cement-like materials that bind soil particles together, is a promising approach to restore mine tailing sites and reduce their mobility and toxicity. However, there is a lack of literature on the combined interactions among mining microbes, tailings residues, biocementation, and low-carbon cement (LCC) prospects. This comprehensive review article explores the prospects of mining microbes for mine tailings restoration using biocementation technology, the key influencing factors and their impact, mechanisms and metabolic pathways, and the effectiveness of biocementation technology in restoring mine tailings sites. In addition, it reviews the utilization of mine tailings materials as an alternative source of cement or construction materials for LCC technology. Furthermore, this review highlights the important issues, challenges, limitations, and applications of biocementation technology for mine tailings rehabilitation. Finally, it provides insights for future research and implementation of biocementation for mine tailings restoration and utilization of tailing materials in the industrial sector to reduce carbon emissions/footprints and achieve net-zero goals.

Accident investigation and lessons not learned: AcciMap analysis of successive tailings dam collapses in Brazil

Accident investigation and lessons not learned: AcciMap analysis of successive tailings dam collapses in Brazil

Coupling reinforcement of uranium tailings via Klebsiella-induced calcium carbonate precipitation and waterborne polyurethane

The environmentally friendly and efficient realization of uranium tailings dam reinforcement is of great significance for the sustainable development of the uranium mining industry. Herein, the effects of microbially induced calcium carbonate precipitation (MICP), using Klebsiella, and waterborne polyurethane (WPU) coupled reinforcement on the mechanical behavior of uranium tailings were studied by triaxial testing. It was demonstrated that the mechanical behaviors of the specimens treated with MICP-WPU coupled reinforcement had a more significant improvement than those treated with MICP alone. When the test confining pressure was 400 kPa, it was found that the peak deviatoric stress of the specimens treated with the coupled reinforcement increased by 45.7 %, the elastic modulus increased by 231.3 %, and the cohesive force was enhanced to 217 kPa as compared to the specimen reinforcement of only MICP induced by Klebsiella. The coupled reinforcement mechanism study using XRD and SEM shows that the significant improvement in the mechanical behavior of the specimens is attributed to the spatial reticular structure formed by wrapping and binding vaterite crystals and tailings particles with WPU. This innovative green reinforcement method is expected to be a new alternative for stabilizing unstable soils in mine geotechnical engineering.

Estimating environmental and cultural/heritage damages of a tailings dam failure: The case of the Fundão dam in Brazil

We present the results of a contingent valuation study aimed at estimating the monetary value of environmental and cultural/heritage injuries caused by the Fundão (tailings) Dam failure in Brazil in 2015 as perceived by the Brazilian population. While the valuation literature on mining-related externalities is considerable, valuation studies of environmental and cultural/heritage injuries resulting from mining incidents are scarce and most available damage assessments apply market valuation methods, while rarely considering environmental and other nonmarket-valued impacts. The flooding and the release of tailings from the Fundão Dam failure led to injuries to sediments, watercourse opacity, and oxygenation, changes in riparian morphology, damages to cultural/heritage resources, mortality to fish and wildlife, changes in the food chain and more along the 675 km watercourse of the Doce River. This was arguably the greatest environmental and cultural/heritage injury ever caused by a single tailings dam collapse. The study followed state-of-the-art recommendations for the development, administration, and data analysis of stated-preference valuation methods. The survey of a representative sample of 5195 Brazilian urban households revealed that the average lower-bound willingness-to-pay estimate to avoid a similar incident in the near future was 137 USD and the parametric-based estimate was 230 USD per household, which aggregates to 7.96 or 12.91 billion USD, respectively. This corresponds to environmental damages of 176 or 295 USD per m3 of tailings released.

Hydrochemistry, Elements Distribution and Their Potential Recoveries in Gold Metallurgical Treatment Tailings Dams

Wastewaters are valuable sources of metals and metalloids and can serve as essential resources for their recovery. Characterizing and understanding the occurrence of metals and other compounds, along with identifying the most effective recovery methods, are key steps in unlocking the potential for reusing these resources. The present study focused on analyzing waters from various mining dams in the Iron Quadrangle (IQ) region of Brazil, which contained metals such as Au, Cu, Ni, Zn, and sulfates resulting from the metallurgical treatment of Au. The results revealed a range of metal concentrations in the neutral zone in three tailings. Additionally, a 3D map was created, and a statistical analysis and an exploration of the processes governing mobility and partitioning were conducted to assess the potential for reuse. Notably, the study identified a high potential for Au recovery, particularly through the utilization of sustainable and cost-effective methods such as nanofibers with biosorbents. Overall, this research contributes to the understanding and exploration of potential reuse procedures for strategic metals in various industrial applications.

A model based on a multivariate classification for assessing impacts on water quality in a DOCE river watershed after the Fundão tailings dam failure

The main purpose of this study was to build multivariate classification models using water quality monitoring data for the hydrographic basin of the Gualaxo do Norte River, Minas Gerais state, Brazil, which was impacted in 2015 by the rupture of a containment structure for iron ore tailings. A total of 27 points were evaluated, covering areas affected and unaffected by the disaster, with monitoring of chemical, physical, and microbiological variables during the period from July 2016 to June 2017. Multivariate classification techniques were applied to the data, with the aim of developing models to determine when the impacted locations would present characteristics equivalent to those existing prior to the rupture. Classification models constructed using PLS-DA and LDA were able to predict three classes: unaffected main river, affected main river, and tributaries. The first technique was able to clearly differentiate the three classes for the data evaluated, achieving averages corresponding to 90% accuracy. The second method was consistent with the first, identifying the chloride content, conductivity, turbidity, and alkalinity as discriminatory variables, among those monitored, with the relationships among the parameters being coherent with the environmental conditions of the region. The model, with a correct classification rate of 91.67%, enabled identification of the behavior of new samples, using only these easily measured variables. In summary, application of the multivariate statistical tools allowed the development of models capable of providing information about the recovery process of an ecosystem impacted by the greatest environmental disaster to have occurred in Brazil.