Tailings Storage Facility Research Articles

Geotechnical and Hydrogeological Zonation of Tailings Storage Facilities: Importance for Design, Construction, Operation, and Closure

This study introduces a conceptual model for understanding the hydromechanical behavior and zonation within tailings storage facilities (TSFs) constructed using the hydraulic backfill method, which constitutes over 98% of TSFs worldwide. The model identifies four distinct zones—dike, discharge, transition, and distal—each characterized by unique physical, geotechnical, and hydraulic properties. Key findings highlight gradients in parameters which systematically vary from the dam toward the settling pond. This study observes that seven parameters such as grain size, friction angle, shear strength, dry density, permeability, shear wave velocities, and liquefaction capacity decrease in value from the dike to the lagoon. Conversely, thirteen parameters such as fine content, porosity, cohesion, plasticity, degree of saturation, volumetric and gravimetric water content, capillary height, specific and volumetric surface of tailings, suction, air and water entry value in the soil water characteristic curve increase in value from the dike to the lagoon. These trends underscore the complex behavior of tailings and their implications for stability, drainage, and environmental impact. By integrating geological, geotechnical, hydrogeological, and geophysical data, this study provides a holistic framework for TSF management, addressing both current challenges and long-term environmental considerations.

Dissolved beryllium (< 1 kDa) mobilized as a major element in groundwater in legacy mine waste.

Research regarding the geochemistry of beryllium (Be) in terrestrial environments is hindered by its high toxicity to humans and the low concentrations normally occurring in the environment. Although Be is considered an immobile element, extremely high dissolved concentrations have been detected in groundwater in the legacy Tailings Storage Facility (TSF) of Smaltjärnen, Sweden. Therefore, a detailed study was conducted to determine physiochemical parameters affecting the speciation of Be in the groundwater. Groundwater was sampled from 2016-2024 and filtered through 0.2 μm filters, whereas truly dissolved fraction (<1 kDa) samples were collected with dialysis membrane tubes in situ at groundwater wells. Secondary minerals on the tailings shore were studied by mineralogical methods and sequential extraction to trace the pathway whereby Be entered the downstream surface water. In part of the tailings, dissolved Be was detected in very high concentrations (average: 4.8 mg/L) in suboxic groundwater with pH from 6.0 to 6.4. Dialysis sampling in 2024 showed that more than 90% occurred as truly dissolved Be (<1 kDa). A significant correlation between Be and S was found, suggesting that sulfate complexes kept Be mobile in these pH conditions. Dissolved Be increased with decreased pH, and there is risk that the concentrations will increase further since sulfide oxidation with subsequent decrease in pH will continue for 100 of years in the TSF. In another part of the TSF, the pH was > 6.4 and dissolved Be was below the detection limit, possibly due to formation of Al(OH)3 (>0.2 μm) together with F and Zn. Secondary minerals on the shore of the tailings functioned as a temporary chemical barrier, scavenging Be primarily by secondary gypsum when present and otherwise by Fe hydr(oxides).

Theoretical and practical substantiation for prediction of equivalent dose rate of gamma radiation at the Sukhachivske tailings storage facility I section

Theoretical and practical substantiation for prediction of equivalent dose rate of gamma radiation at the Sukhachivske tailings storage facility I section

Experimental study on the sedimentary structure of tailings storage facilities

Experimental study on the sedimentary structure of tailings storage facilities

Slope Stability Assessment of Tailings Dam

The paper examines a complex methodology for calculating the slope stability of a tailing storage facility based on comparing the results obtained through deterministic and probabilistic approaches. The analysis is performed in GeoStudio software, based on the limit equilibrium method, and with a probabilistic approach that uses a Monte Carlo simulation to compute a probability distribution of the resulting factor of safety. A slope stability assessment of tailing dam was conducted on the example of Ferrexpo Poltava Mining, and a conclusion was reached about their reliability and safety. The results of the deterministic analysis showed that the calculated factor of safety is by those established in Ukrainian regulatory standards. It has been recognized that the factor of safety is not a consistent measure of risk for tailings dam. Considering the variability inherent in the soil materials of tailings dam is a way to achieve more accurate results. The importance of obtaining a failure probability and a reliability index due to tailing dam stability was highlighted by comparing deterministic and probabilistic approaches.

Influence of Environmental Conditions on the Behaviour of Tailings from Tungsten Mining for Sustainable Geotechnical Applications and Storage

Modern societies require increasingly large amounts of minerals and metals for their development. Therefore, huge amounts of waste must be stored in safe and cost-effective massive tailing storage facilities that would benefit from using tailings in sustainable geotechnical applications within the context of the circular economy. However, to consider tailings as assets, the long-term behaviour of these unconventional geomaterials under realistic environmental conditions must be assessed. This paper focuses on the effects of the environmental conditions on the behaviour of tailings from tungsten mining by experimentally determining their major physical and mechanical properties for three different conditions: twenty-months-aged undisturbed samples and reconstituted samples, with the latter being fresh and three months. The results confirm that twenty-months-aged undisturbed and fresh reconstituted tailings have significantly different mechanical behaviour, while three-months-aged reconstituted samples show an in-between behaviour as if the material regenerates and improved its behaviour with time due to physical and chemical processes. These ageing processes are experimentally confirmed by measuring the electrical conductivity in the samples. The results confirm that optimising the design of tailing storage facilities and using these geomaterials in sustainable geotechnical applications must consider the existing environmental conditions and the potential tailings’ mechanical changes due to ageing.

Results of a dilatancy round robin

The critical state approach currently finds widespread adoption in geotechnical engineering practise, particularly with respect to tailings storage facilities. The laboratory component of such works usually involves determination of the critical state line (CSL) followed by stress- and state-dilatancy behaviour in triaxial compression conditions, characterised by the volumetric coupling parameter Ntc and the state dilatancy constant χtc. While the reliability of CSL testing using current state of practise methods has been recently demonstrated, it is currently unclear how reproducibly Ntc and χtc can be obtained. To investigate this, a dilatancy round robin programme was carried out by five laboratories who regularly carry out such testing. In the first stage of the programme, each laboratory adopted a version of ‘densification in layers’, either dense moist tamping or vibration-densification. While a generally consistent Ntc was observed, significant variation in χtc was seen. To further investigate this variation, a second stage was carried out where slurry deposition and the ‘air-dried’ technique were used. These techniques showed better agreement between laboratories, while also producing lower values of χtc than densification in layers. Some potential implications of these observations on current tailings engineering laboratory testing practise are outlined.

Ground Models for Tailings Management

Tailings and tailings storage facilities (TSF) are an unavoidable by-product of mining, the improper design, construction, and management of which has historically caused significant environmental and societal impacts. The 2020 ‘Global Industry Standard on Tailings Management’ (GISTM) was introduced into tailings management practice to “achieve the ultimate goal of zero harm to people and the environment and zero tolerance for human fatality” and provides the framework by which facility operators, designers, consultants, and other stakeholders approach tailings management. GISTM includes the requirement of a site characterisation, considered to be an equivalent to an Engineering Geological Model (EGM). The development of robust site characterisation(s) for tailings management is considered to require a series of interrelated ground models that make up the EGM and critically include a conceptual geological model, a total geological history approach, and a component of digital modelling. This paper provides a framework for the development of ground models for tailings management through the complete TSF lifespan, from concept to closure; by the reinterpretation of existing ground model literature in a mine-waste specific and GISTM compliant context.

Spatial and Temporal Analysis of Surface Displacements for Tailings Storage Facility Stability Assessment

Monitoring the stability of tailings storage facilities (TSFs) is extremely important due to the catastrophic consequences of instability, which pose a threat to both the environment and human life. For this reason, numerous laboratory and field tests are carried out around dams. An extensive database is collected as part of monitoring and field research. The in-depth analysis of available data can help monitor stability and predict disaster hazards. One of the important factors is displacement, including surface displacements—recorded by benchmarks as well as underground displacements—recorded by inclinometers. In this work, methods were developed to help assess the stability of the TSF in terms of surface and underground displacement based on the simulated data from geodetic benchmarks. The context of spatial correlation was investigated using hot spot analysis, which shows areas of greater risk, indicating the places of correlation of large and small displacements. The analysis of displacements versus time allowed us to indicate the growing exponential trend, thanks to which it is possible to forecast the trend of future displacements, as well as their velocity and acceleration, with the coefficient of determination of the trend matching reaching even 0.97. Additionally, the use of a geographically weighted regression model was proposed to predict the risk of shear relative to surface displacements.

Tackling soil erosion and contamination within the SDGs framework: a case study of the Erdenet copper-molybdenum mine

Mining operations in Mongolia have contributed significantly to national economic growth. However, the lack of adequate mine land rehabilitation practices has resulted in various forms of land degradation, including land cover change, soil erosion and contamination with heavy metals and metalloids. These issues have negatively affected ecosystems and posed potential risks to human health due to the interconnected relationships between land, water and human activities. This study focuses on the copper-molybdenum mining site of Erdenet, the oldest and one of the largest copper mines in Mongolia, to investigate the main drivers of soil degradation and evaluate effective rehabilitation strategies. By combining findings from our previous studies on soil erosion and contamination in the Erdenet area with a review of existing research, we assess key rehabilitation priorities. Taking a Nexus approach, this study explores the interconnections between environmental, economic and social sectors, emphasizing the importance of balancing mining activities with sustainable land management. The previous studies suggest that for the next 10–15 years, priorities should focus on tailings storage facility rehabilitation and soil contamination remediation, while longer-term goals include developing sustainable environmental management strategies that foster cooperation between mining corporations and local communities, enforce regulations and improve monitoring in the Erdenet mining area. The study aligns these priorities with the Sustainable Development Goals, offering science-based recommendations for managing soil erosion and reducing contamination.

Review of the Failure at the Flotation Tailings Storage Facility of the “Stolice” Mine (Serbia)

A detailed analysis of the accident that occurred at the flotation tailings storage facility (TSF) at the inactive mine “Stolice” in 2014 is provided in this paper. All factors that caused the accident have been analyzed, with a review of the consequences of the accident, their accident class according to the Global Industry Standard on Tailings (GISTM), and the implemented measures to rehabilitate the TSF and the surrounding area after the accident. It has been concluded that the TSF had not been properly maintained even before the accident occurred and that the unfavorable weather conditions in Serbia in the May of that year contributed to the filtration disturbance and multiple tailings spillages from the TSF. It has been stated that the consequences according to the GISTM span from “low” to “significant”, with the group of environmental consequences having the highest rank (3). Although the accident occurred without recorded human casualties, with the damage being of a local nature, it is considered one of the most significant accidents at a TSF in Serbia in the last 20 years. The reconstructed TSF is considered stable now, with a low-to-medium risk of failure.

Evaluation of state parameter interpretation methods using CPT calibration chamber data

The cone penetration test (CPT) is widely used to determine the in situ state parameter of soils because it provides continuous data and excellent repeatability at a relatively low cost. Accurate interpretation of the state parameter from CPT is the basis for evaluating the strength of granular soils, including assessing liquefaction susceptibility in important structures such as tailings storage facilities. A few interpretation methods are used in practice. They use two different overburden stress normalisation schemes on tip resistance. These methods vary in how much information they utilise to differentiate among soils. This paper evaluates these methods by applying them to an extensive database of calibration chamber tests. Then, the state parameter interpreted by each method is compared with that determined from laboratory data. The database includes manufactured sands, natural sands, and clean sand tailings. The soils were selected such that both calibration chamber testing and triaxial compression data were available from the literature. This evaluation serves as a minimum requirement for applying these methods in engineering projects, especially those dealing with challenging soils such as fines-rich tailings. This study suggests that methods that account for soil properties and in situ horizontal stresses perform better than those that do not.

Tailings storage facilities in China: Historical failure incidents, existing status, and database-driven quantitative risk assessment

Tailings storage facility (TSF) failures in China have historically resulted in downstream consequences, including fatalities, economic harm, and environmental contamination. However, the nation-wide documentation on existing TSFs is incomplete, and the magnitude-frequency statistics of the failures are poorly quantified. These gaps have impeded ongoing efforts of risk assessment and mitigation. This study collates and analyzes new databases on historical TSF failures and existing TSFs in China. We report 143 TSF failures in China over the period 1957–2023, which exceeds the number (∼20) reported in previous studies. Magnitude-frequency statistics indicate that the mean return period for TSF failures in China with at least 10 fatalities is ∼5 years, while for those with released volumes >1 million m3 is ∼16 years. Our review confirms that there are at least 14,217 existing TSFs in China; therefore, the cumulative failure rate of TSFs in China is estimated to be ∼1 %. We supply a database of 1853 TSFs that lists the statistics such as storage volume and dam height. Using these datasets along with downstream demographic statistics, we undertake a regional risk assessment for Jilin Province, which identifies 11 TSFs with intolerable risks. Among these, the most critical TSF poses a potential loss of 175 lives. Our findings provide the most comprehensive picture of TSFs in China to date. We anticipate that this study will advance tailings disclosure practices in China and support screening-level risk assessments by provincial regulators to help prioritize community engagement and risk mitigation efforts.

Comparative stability analysis of tailings dams using limit equilibrium and finite element methods

This paper presents a case study of stability assessment conducted on a tailings storage facility divider dam. The stability utilized limit equilibrium (LE) with Slope/W, incorporating various commonly used slip surface searching options, and the finite element method (FEM) with Plaxis2D under static peak and post liquefaction conditions. The results reveal a significant variation in the factor of safety (FoS) obtained from LE (FoSLE), depending on the selected slip surface searching options. Notably, the commonly used searching options in Slope/W can yield significantly higher FoS than those obtained from Plaxis2D. This observation prompted the adoption of the fully specified (FS) searching option in Slope/W, where the critical slip surface was aligned with that determined by Plaxis2D, resulting in comparable results to Plaxis2D. The FoSLE obtained by FS closely approximated FoSFEM, with a difference of 3.4% under static peak and 15.4% under post-liquefaction conditions. The results indicate that certain slip surface searching options in LE may fail to accurately identify the critical slip surface, leading to an overestimation of the FoS for a given geometry. The FEM, on the other hand, can provide valuable insights by identifying potential critical slip surfaces that may not be identified in LE.

Effect of shear-induced consolidation on the behaviour of a loose silt tailings

Tailings within a tailings storage facility (TSF) are subjected to monotonic loading and consolidation following tailings depositions into the impoundment and perimeter embankment raises. The aim of the current study was to identify how monotonic loading followed by consolidation influences the behaviour of a loose silt tailings deposit. The study quantified the effect of magnitude and duration of an applied monotonic load on the evolving undrained shear strength using triaxial testing. It also showed that peak undrained shear strengths are reached under lower shear-induced excess pore pressures and axial strains than inferred from standard triaxial testing. While the study showed how tailings benefitted from gains in peak undrained shear strength, it also highlighted some potential negative implications for timely detection of precursors to failure of TSFs by means of conventional monitoring.

Conceptual and Applied Aspects of Water Retention Tests on Tailings Using Columns

The water retention capacity of porous materials is crucial in various geotechnical and environmental engineering applications such as slope stability analysis, landfill management, and mining operations. Filtered tailings stacks are considered an alternative to traditional tailings dams. Nevertheless, the mechanical behaviour and stability of the material under different water content conditions are of concern because these stacks can reach considerable heights. The water behaviour in these structures is poorly understood, particularly the effects of the water content on the stability and potential for liquefaction of the stacks. This study aims to investigate the water retention and flow characteristics of compacted iron ore tailings in high columns to better understand their hydromechanical behaviour. The research used 5 m high columns filled with iron ore tailings from the Quadrilátero Ferrífero region in Minas Gerais, Brazil. The columns were prepared in layers, compacted, and instrumented with moisture content sensors and suction sensors to monitor the water movement during various stages of saturation, drainage, infiltration, and evaporation. The sensors provided consistent data and revealed that the tailings exhibited high drainage capacity. The moisture content and suction profiles were effectively established over time and revealed the dynamic water retention behaviour. The comparison of the data with the theoretical soil water retention curve (SWRC) demonstrated a good correlation which indicates that there was no hysteresis in the material response. The study concludes that the column setup effectively captures the water retention and flow characteristics of compacted tailings and provides valuable insights for the hydromechanical analysis of filtered tailings stacks. These findings can significantly help improve numerical models, calibrate material parameters, and contribute to the safer and more efficient management of tailings storage facilities.

Establishing a tailings storage facility database in Gauteng

As an initial step of zero harm, an understanding of the scale and magnitude of Tailings Storage Facilities (TSFs) is necessary for risk assessments. There is no publicly available TSF database in each South African province with details on TSF distribution of risks and characteristics. TSF-related cases such as the Jagersfontein Tailings Dam failure and the crime challenges by illegal miners at the North Sands Dump are significant motivations to establish a publicly accessible TSF database, especially in Gauteng. The objectives of the study were to establish a TSF database comprising the spatial distribution of TSFs and to classify each TSF by its operational activity status. The Department of Mineral Resources and Energy publishes data on TSFs, and it was used to create the database. Due to coordinate data limitations, only 94 TSFs could be presented on ArcGIS Pro. The study finds that there is almost an equal split of active and inactive TSFs in Gauteng. Most active TSFs are situated in the East Rand of Gauteng. Furthermore, companies that own some of the TSFs in Gauteng include Durban Roodepoort Deep Gold, which owns 70 % of TSFs, followed by AfriSam (6 %) and Blyvoor Gold (4 %). Companies need to disclose all their TSF data to strengthen the database.

Characterization and evaluation of gold mill tailings as an additive in cement-stabilized products

Abstract Gold mill tailings (GMT) are waste from gold mill processing plants usually collected and stored in tailings storage facilities (TSF) and left for years in many abandoned mines in the world. GMT is in large amounts and contains high concentrations of chemicals and compounds that may harm human lives and the ecosystem if not well-maintained. A characterization study is conducted on GMT from a small-scale mill processing plant in Agusan del Sur, Philippines, and its potential utilization as an additive to sand and cement in making cement-stabilized products is also evaluated. The elemental and oxide composition, the presence of free and total cyanide, and particle size analysis were determined. Different proportions of gold mill tailings, cement, and sand were prepared and tested for compressive strength and water absorption. The results showed that the GMT contained some potentially valuable elements like tin, zinc, and europium. GMT also contains potentially hazardous elements like lead (663ppm), arsenic (157ppm), and mercury (17ppm). The free cyanide in the effluent is also found at 1.9 ppm. These elements and compounds are potentially hazardous in case of tailings seepage or overflow to groundwater and neighboring agricultural lands. The evaluation of cement-stabilized samples shows that the GMT from the study area can be utilized as an additive to cement and sand in the production of cement-stabilized products however it must be properly treated and handled to ensure the safety of workers. The TCLP result showed that the product is non-toxic and non-reactive. The construction and proper maintenance of a TSF for small-scale gold milling plants in the study area is recommended to prevent environmental, health, and safety risks.

Mineralogical Impact on the Compaction of Residual Gabbro Soils in the Construction of Platinum Tailings Storage Facilities

Over the past decade, there have been 45 tailings storage facility (TSF) disasters worldwide resulting in fatalities, serious environmental damage, and the destruction of entire ecosystems. These failures often stem from substandard design or operational practices. Many TSFs are constructed in regions associated with intrusive mafic rocks such as gabbro, norite, pyroxenite, and anorthosite, which are commonly found alongside platinum group metals in areas like the Bushveld Igneous Complex in South Africa and the Great Dyke in Zimbabwe. The stability of these structures can be significantly influenced by the residual soils present at the construction sites. Residual soils, both cohesive and non-cohesive, contain varying quantities of different minerals, which can impact the compaction characteristics and, consequently, the stability of the TSF foundations. Cohesive soils rich in clay minerals, such as kaolinite and smectite, exhibit properties that can hinder effective soil compaction. The expansive nature of smectite due to its ability to absorb large amounts of water and host free exchangeable cations counteracts the compaction process, reducing soil stability. Soil compaction is a complex process influenced by several factors, including compaction effort, method, water content, particle size distribution, and mineralogy. This study aimed to analyse these factors using a series of laboratory tests, including foundation indicators, MOD AASHTO compaction testing, and X-ray diffraction analysis, on residual soils from two TSF construction sites. The findings revealed that soils with high clay content tend to retain more water and have a higher optimum water content, adversely affecting their compaction properties. This study highlights the critical need to consider the mineralogical composition and weathering effects of residual soils in the design and construction of TSFs. By improving our understanding of these factors, we can enhance the stability of TSF foundations, reducing the likelihood of future failures. The insights gained from this research highlight the importance of thorough geotechnical assessments in the successful design and maintenance of TSFs.

Response Surface Design Models to Predict the Strength of Iron Tailings Stabilized with an Alkali-Activated Cement

Tailing storage facilities are very complex structures whose failure generally leads to catastrophic consequences in terms of casualties, serious environmental impacts on local biodiversity, and disruptions in the mineral supply. For this reason, structures at risk must be reinforced or decommissioned. One possible option is its reinforcement with compacted filtered tailings stabilized with binders. Alkali-activated binders provide a more sustainable solution than ordinary Portland cement but require an optimization of the tailing–binder mixture, which, in some cases, can lead to a substantial experimental effort. Statistical models have been used to reduce the number of those experiments, but a rational design methodology is still lacking. This methodology to define the right mixture for a required strength should consider both the mixture components and in situ conditions. In this paper, response surface methods were used to plan and interpret unconfined compression strength test results on an iron tailing stabilized with alkali-activated binders. It was concluded that the fly ash content was the most important parameter, followed by the liquid content and sodium hydroxide concentration. From the obtained results, several statistical models were defined and compared according to the definition of a strength prediction model based on a mixture index parameter. It was interesting to observe that models with the porosity cement index still provide reasonable adjustment even when different tailings’ water contents are considered.