Post-mining landscapes are expected to constitute significant portions of closure environments worldwide, and restoring these sites to stable, sustainable conditions is a major priority for industry, regulators, and society. Reclamation efforts focus on reconstructing functioning landscapes that achieve long-term geotechnical, hydrological, and ecological stability. Success depends on advances in mine waste characterization, landform and soil cover design, water and contaminant management, and the development of resilient ecosystems. Addressing these challenges requires interdisciplinary collaboration across mining engineering, geology, geochemistry, geophysics, soil science, hydrology, ecology, and environmental sciences.
This session aims to highlight recent research and practical advances in understanding and managing post-mining geo-environmental issues across diverse mining contexts and regions. Topics include mine-induced subsidence and instability, soil and water contamination and remediation, air quality impacts, land and ground-space utilization, reclamation strategies, and integrated approaches to long-term post-mining risk control. By sharing global perspectives and interdisciplinary insights, this session seeks to advance sustainable solutions for post-mining landscapes.
Orals: Wed, 6 May, 08:30–12:30 | Room 0.51
The diverse geology and geomorphology of Western Canada have facilitated the development of a mature mining industry. A variety of commodities such as metals, bitumen, and coal are mined across mountainous, Arctic, and boreal forest regions. In parallel with industrial development, significant research on mine waste and reclamation has occurred in the Western Canadian provinces and territories. In this presentation, the timeline of mine waste research at a Western Canadian university (the University of Alberta) is used to illustrate how perceptions of the geotechnical challenges of mine waste materials and reclamation priorities have evolved over the past 5 decades.
Academic research on oil sands tailings, a fine-grained waste product produced by bitumen mining, began in the 1970s with early work focused on characterizing geotechnical behaviour. The goal of much of this work, from its early stages until the present day, has been to understand consolidation behaviour, which contributes to the challenges of dewatering oil sands tailings. This included a 30-year long standpipe experiment beginning in 1982, and continued interest in consolidation contributed to the construction of Western Canada’s only geotechnical beam centrifuge in 2012 to simulate the effects of long term vertical stress. Starting in the 1990s, different methods of dewatering tailings to speed reclamation progress have been studied, ranging from physical processes such as freezing and thawing to more recent studies on polymer chemical amendments.
Similar to other jurisdictions, acid rock drainage (ARD) is a significant concern for many hard rock mines in Western Canada. Due to the cold climate of the region, a number of studies have investigated the effect of freezing temperatures on ARD. Computer modelling of temperature and water flow in mine waste to predict ARD has been a research focus since the 2010s. This has led to recent research on soil covers and novel mine waste disposal methods such as filtering and commingling.
The importance of tailings and reclamation research to the mining industry in Western Canada is exemplified by longstanding collaborations with major mining operations and government regulators. This has enabled the application of continuously-evolving geotechnical best practices to academic research. As more rigorous methods of soil mechanics analysis, such as unsaturated and critical state soil mechanics, have been developed, they have been increasingly applied to mine waste. More recently, developing risk-based design approaches for reclamation strategies has been an area of research focus.
Over the past 5 decades, research on tailings and reclamation in Western Canada and beyond has evolved from early geotechnical characterization of mine waste to the development of novel management strategies. While this represents a remarkable technical achievement, the development of resilient reclamation ecosystems remains a challenge. It is suggested that future geotechnical research on tailings and reclamation should prioritize interdisciplinary collaboration to support the development of safe, sustainable, and resilient post-mining landscapes.
How to cite: Paul, A., Barsi, D., Dos Santos Cardoso Coelho, P., Waseem, O., Whitehead, C., and Zheng, T.: Evolution of tailings and reclamation research in Western Canada: 1970 - 2026, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-16014, https://doi.org/10.5194/egusphere-egu26-16014, 2026.
A long history of mining has resulted in hundreds of tailings cells in Canada that are orphaned or abandoned. Often the only feasible restoration strategies for such tailings, due to financial constraints, are facilitation of natural revegetation or surface amendment followed by direct planting into tailings. Small changes in substrate conditions, therefore, can have large impacts on revegetation success. This research focuses on a 2.6 km2 gold mine tailings impoundment in northern Ontario, Canada. Over three years, samples were collected from multiple locations and depths across the tailings cell and directly from the processing plant. Elements of interest include S, Cu, and Cr. Metal concentrations were measured using ICP-MS and changes in elemental speciation were measured using synchrotron x-ray absorption spectroscopy. Cr is unchanged along sampling gradients, while S and Cu exhibit great variation in their chemical state along sampling gradients. Results surprisingly show that trace organic carbon from gold processing has a strong effect on Cu speciation, and we further discuss the efficacy of correlating proxy measures of chemical states (e.g. S redox state, pH, conductivity, and carbon content) to Cu and Cr speciation. The results from this research provide insights into how chemical characteristics, including elemental speciation, can vary across time and spatial scales in mine tailings impoundments and what processes may be driving these changes. Future work should consider the described processes when designing sampling methodologies and restoration strategies of similar tailings impoundments.
How to cite: Lundell, L., Peak, D., and Stewart, K.: Investigating processes driving copper, chromium, and sulphur chemistry changes across space and time in a boreal Canadian gold mine tailings impoundment , EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-15907, https://doi.org/10.5194/egusphere-egu26-15907, 2026.
Lignite open-pit mining causes long-term disturbances of natural soils with losses of their environmental functions. Oxidation of sulfide minerals in the dumped overburden of coal mines and subsequent leaching increase iron and sulfate concentrations in groundwater. If these waters reach the surface and become exposed to oxygen or elevated pH conditions, iron precipitates as iron hydroxide sludge (IHS). The large volumes of IHS generated annually pose a significant environmental challenge due to their complex and costly disposal. Soils developing on post-mining dump substrates in Lusatia are often characterized by high sand contents, poor structure, low water-holding capacity, and a limited ability to retain nutrients and, in particular, organic matter. In contrast, iron hydroxides provide highly reactive surfaces that can effectively bind soil organic matter (SOM), thereby improving soil structure as well as water and nutrient retention. The potential use of IHS in post-mining soil reclamation therefore warrants systematic scientific investigation. The proposed approach offers opportunities and challenges. While IHS may enhance carbon storage and other soil functions, there is a risk of releasing associated potentially toxic elements (PTEs) or immobilizing nutrients on iron oxide surfaces. Here we report results from the first year of a three-year lysimeter experiment evaluating IHS application under field conditions. We quantified potential PTE release as well as water balance, nutrient availability, and effects on SOM contents. Overall, our study provides first evidence on whether the use of acid mine drainage-derived IHS can contribute to the improvement of previously unproductive and low SOM post-mining soils.
How to cite: Stein, M., Herrmann, J., Harlow, E., Winkler, P., and Mikutta, R.: New perspectives in post-mining soil restoration: Use of iron hydroxide sludge from acid mine drainage as soil ameliorant, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-21213, https://doi.org/10.5194/egusphere-egu26-21213, 2026.
Open-pit mining severely disturbs land by removing vegetation, altering soils, degrading soil structure, and promoting soil erosion and nutrient loss. Waste rock and tailings can release toxic trace elements (TEs), which may be taken up by plants and transferred through the food chain, thereby exposing humans and wildlife to contamination. These long-lasting ecological and health risks highlight the need for soil rehabilitation, vegetation recovery, and ongoing environmental monitoring.
Within this context, reclaimed sites located in a bitumen mining and upgrading area in Alberta, Canada, were selected to: (i) assess the potential bioavailability and transfer of TEs from cover soils to wild berries growing on them; (ii) evaluate the extent to which TEs are enriched in berries from reclaimed lands compared to natural background levels; and (iii) compare TE concentrations in berries with existing thresholds intended for human consumption.
Following metal-free, ultra-clean laboratory procedures, soils and eight species of unwashed berries collected in 2024 were dried and milled, digested in HNO₃, and analyzed using ICP-MS. Phytoavailable TEs in soils were determined following extraction with DTPA. Micronutrients (Cu, Mn, Ni, and Zn), bitumen-enriched elements (Mo, Re, Se, and V), and chalcophile elements (As, Ag, Cd, Pb, Sb, and Tl) were below the remediation guidelines for natural areas in Alberta. Average TE concentrations in these soils were also lower than those reported for soils worldwide and were either lower than or comparable to concentrations in regional parent materials. Based on DTPA soil extracts, it was estimated that 0.1–23% of bitumen-enriched elements, 0.1–75% of chalcophile elements, and 0.1–25% of micronutrients are potentially available for plant uptake.
To distinguish between TE deposition on berry surfaces and root uptake, linear regressions were performed between TE concentrations and conservative lithophile elements (Al, Th, and Y), and Y-normalized TE concentrations in berries were compared with those in soils. These analyses indicate that As, Sb, Pb, Tl, and V are predominantly deposited on berry surfaces (R² > 0.6), whereas Ag, Cd, Cu, Mn, Mo, Ni, and Zn (R² < 0.6) are primarily taken up from the soil. Iron, an essential and abundant element in soils, occurs both internally and on the surface of berries. With the exception of Mn and Mo, TE concentrations in unwashed berries from reclaimed sites were 2-fold (Cd, Cu, Zn) to 38-fold (Y) higher than those measured at remote locations. These differences are attributed to berry species as well as greater dust deposition at reclaimed sites compared to remote areas.
After accounting for the average berry water content (80%), TE concentrations were 7–17 times lower than EU guidelines for safe consumption (30–40 µg/kg for Cd and 100 µg/kg for Pb). However, these results should be interpreted cautiously, as population-related factors such as age, dietary habits, and risk perception must also be considered.
How to cite: Barraza, F., Nelson, E., Ybañez, Q., Thirupurasanthiran, S., Moffett, K., Bujaczek, T., and Shotyk, W.: Trace elements in soils from reclaimed lands and their bioavailability in wild berries , EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-14587, https://doi.org/10.5194/egusphere-egu26-14587, 2026.
Placing reclamation covers is an effective method to reduce NO3- release from coal gangue. This study considered the impacts of different reclamation covers on the contributions and release of NO3- from explosive and exchangeable NH4+ (NH4+-ex) sources in coal gangue using column experiments. The δ18O-NO3- values were measured to identify the sources of NO3- in coal gangue, and the calibrated and validated hydraulic and solute parameters were used to simulate the release of NO3- for all treatments (without cover, CK; 30 cm sandy loess, T1; 30 cm Pisha sandstone, T2; 30 cm mixed soil, T3; 15 cm Pisha sandstone overlying 15 cm sandy loess, T4; and 15 cm sandy loess overlying 15 cm Pisha sandstone, T5). The results indicated SEEP/W and CTRAN/W with optimized parameters could accurately simulate water movement and NO3- transport. The contribution of the explosive source was 80, 81, 86, 82, 84, and 84% and of the NH4+-ex source was 20, 19, 14, 18, 16, and 16% for CK, T1, T2, T3, T4, and T5, respectively. The five covered treatments respectively decreased the total cumulative water volume by 5.80, 11.11, 7.73, 9.18, and 10.63% and the total NO3- cumulative mass released from the coal gangue by 5.59, 20.95, 7.41, 14.61, and 14.36% compared to CK. Our results suggest the reclamation covers significantly reduced the release of NO3- from coal gangue primarily by decreasing the release of NO3- derived from the NH4+-ex source, with the most significant effect noted for the 30 cm Pisha sandstone cover (T2).
How to cite: Huang, M. and Liu, X.: The impact of different reclamation covers on the release of nitrate from various sources in coal gangue, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-2016, https://doi.org/10.5194/egusphere-egu26-2016, 2026.
Mining environments exhibit geochemically dynamic landscapes driven by geogenic and anthropogenic processes, resulting in the deterioration of groundwater and surface water quality. The hydrogeological alterations in such settings further facilitate contaminant mobility, thereby increasing the vulnerability of (sub)-surface water resources to contaminant transport. This study presents an integrated hydrogeological and hydrochemical framework to delineate contaminant pathways and understand (sub)-surface hydrochemical processes in a semi-arid mining region. To operationalize this framework, a series of electrical resistivity tomography (ERT) surveys were conducted to characterize subsurface heterogeneity and identify potential pathways for contaminant movement. The ERT survey was followed by (sub)-surface water quality analysis to understand the hydrochemical process governing water contamination. The resistivity variations in ERT profiling revealed distinct subsurface geological formations. The low resistivity values varying from 2.99 to 10 Ωm reflected aquifers saturated with a possible contaminated plume from either surface runoff or anthropogenic mining activities. The high resistivity values (>100 Ωm) corresponded to weathered formations, which serve as active sites for geogenic rock-water interactions. The entropy water quality index revealed distinct spatial variations in contaminant levels, whereas principal component analysis distinguished between anthropogenic and geogenic factors influencing water quality in the mining-impacted region. The isotopic composition of groundwater (δ²H = 3.67·δ¹⁸O – 17.09) indicated recharge from an evaporatively modified, surface-influenced source, suggesting increased susceptibility to surface-derived contamination, whereas the surface-water samples (δ²H = 5.70·δ¹⁸O – 13.94) primarily reflected evaporative enrichment. Overall, the integrated hydrogeological and hydrochemical framework is found to be effective for understanding the key subsurface processes that drive contaminant mobility and deterioration of water quality in mining regions.
Keywords: Hydrogeological alterations, Contaminant mobility, ERT profiling, Electrical resistivity tomography, Rock-water interactions
How to cite: Singh, B. and Yadav, B. K.: Unraveling (Sub)-surface Water Dynamics in a Mining Environment: Hydrogeological and Hydrochemical Insights, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-472, https://doi.org/10.5194/egusphere-egu26-472, 2026.
Froth treatment tailings (FTT) are a byproduct of bitumen extraction in Alberta’s oil sands and, while the smallest tailings stream by volume, they present disproportionate challenges for closure and reclamation. Produced during froth treatment, where diluent such as naphtha is added to separate bitumen from water and solids, FTT contain residual hydrocarbons and sulfide minerals like pyrite. These constituents can influence redox conditions, microbial activity, and hydrocarbon degradation processes, ultimately affecting long-term deposit behavior. Despite their importance, FTT remain understudied compared with other tailings types, especially in the context of terrestrial beach deposits targeted for reclamation.
This study investigated the spatial and vertical distribution of hydrocarbons and microbial communities across a 1.4 km transect of a naphtha-based FTT beach deposit at Syncrude’s Mildred Lake Settling Basin. Samples were collected from six locations spanning the pond edge to a reclamation dyke, with depths ranging from 0.15 to 46 m. Chemical analysis revealed that petroleum hydrocarbon (PHC) and residual naphtha concentrations reflected deposition history, with higher concentrations found in deeper, older FTT near the dyke and at shallower depths adjacent to the pond. Naphtha concentrations were most strongly correlated with heavier PHC fractions (F2–F4), while toluene and ethylbenzene emerged as key indicators of microbial variation.
Distinct microbial communities were observed in FTT relative to the underlying coarse tailings, with reduced diversity at depths greater than ~30 m. FTT were enriched in hydrocarbon degraders (e.g., Pseudomonas), sulfur-cycling taxa (Thiobacillus, Desulfovibrio, Desulfotomaculales), and methanogens (Methanosaeta). Community composition varied with depth, distance from the pond, and presence of FTT, with the strongest drivers being PHC concentrations and pyrite content. These findings suggest that residual hydrocarbons act both as substrates and stressors, shaping microbial ecology while interacting with geochemical processes such as sulfur reduction and oxidation as well as methanogenesis.
Together, this work provides one of the first spatially resolved assessments of FTT deposits illustrating how residual diluent, hydrocarbons, and microbial processes interact to influence subsurface conditions. Accurate characterization of FTT is essential for predicting long-term behavior, guiding the design of closure landforms, and informing reclamation monitoring programs.
How to cite: Balaberda, A., Escolástico-Ortiz, D., Martineau, C., Heshka, N., Lindsay, M., and Degenhardt, D.: Characterizing Residual Hydrocarbons and Microbial Dynamics in Froth Treatment Tailings for Reclamation Planning, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-7788, https://doi.org/10.5194/egusphere-egu26-7788, 2026.
Open-pit coal mining exerts long-lasting and cumulative disturbances on terrestrial ecosystems during the post-mining stage, and the associated environmental impacts and recovery processes exhibit pronounced temporal persistence and spatial heterogeneity. Long-term remote sensing monitoring is therefore essential for understanding post-mining ecosystem dynamics and evaluating restoration outcomes. In this study, we constructed a Mining Landscape Disturbance Index (MLDI) and a Mining Landscape Recovery Index (MLRI) based on the Enhanced Vegetation Index (EVI) and Land Surface Temperature (LST). Combined with the LandTrendr algorithm, post-mining disturbance-recovery trajectories of 46 open-pit coal mines in northern China were systematically monitored and analyzed over the period 1984-2025. Using disturbance and recovery trajectory information extracted by LandTrendr, ecosystem resilience was comprehensively assessed from three dimensions: resistance, recovery capacity, and stability. Based on disturbance magnitude and recovery magnitude, the 46 mining areas were classified into four types: high disturbance-high recovery (HH), high disturbance-low recovery (HL), low disturbance-high recovery (LH), and low disturbance-low recovery (LL). The results indicate that the median MLRI values of all four types show an overall increasing trend at the interannual scale, suggesting a general post-mining recovery tendency of ecosystems during the study period, although significant differences exist in recovery levels and recovery rates among different types. Meanwhile, the median MLDI values also exhibit a continuous upward trend, reflecting persistent cumulative degradation pressure on mining ecosystems under long-term mining activities. Distinct multidimensional differentiation patterns were observed among the four disturbance-recovery types in terms of resistance, recovery capacity, and stability. This study provides an effective remote sensing-based framework for monitoring long-term post-mining ecological dynamics and offers scientific support for differentiated environmental management and ecological restoration strategies in post-mining areas.
How to cite: Liu, Y. and Xie, M.: Post-mining Ecological Disturbance-Recovery Trajectories and Resilience Assessment of Open-pit Coal Mines Based on Long-term Remote Sensing Indices, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-7127, https://doi.org/10.5194/egusphere-egu26-7127, 2026.
This research presents an integrated methodology for enhanced slope stability analysis in mining areas by merging remote sensing, artificial intelligence, and temporal deep learning. It advances beyond traditional numerical models by utilizing multi-source satellite data (Sentinel-1, Sentinel-2, DEM) to extract critical stability parameters—including slope angle, deformation, and rainfall intensity, among others within a multimodal geographic information system (GIS) environment. Current research focuses on generating a pixel-level risk-susceptibility map of the stability of mining slopes and classifying them into different risk zones — high, medium, and low by integrating fuzzy logic and multi-criteria decision-making (MCDM) techniques. Subsequently, the identified high-risk zones are processed to analyze temporal patterns and mine expansion/deformation in land from time-series imagery using a ConvoLSTM/U-Net deep learning model, thereby improving predictive capability for evolving slope geometries. The methodology has been validated through field surveys using drone imagery and laboratory tests of physico-mechanical properties on rock and dump samples. These support the interpretation of remote sensing–derived slope deformation and stability patterns. Ultimately, this research offers a cost-effective, scalable solution for predicting and monitoring OB dump slope stability by integrating remote sensing and AI, filling gaps left by traditional methods.
How to cite: Agarwal, S., Kumar, P., Sahoo, M. M., and Reale, G.: Beyond Numerical Modeling: An Integrated Remote Sensing and AI Methodology for Rapid Slope Stability Analysis in Mining Regions, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-5418, https://doi.org/10.5194/egusphere-egu26-5418, 2026.
Tailings materials are inherently heterogeneous systems where deposition processes produce layering, segregation, and spatial variability in density and structure. Conventional analyses often neglect this spatial variability and instead rely on a single deterministic representation of in-situ state. This study presents a practical framework to assess tailings storage facility (TSF) stability by integrating random field theory with the NorSand model, which explicitly links strength, dilatancy, and static liquefaction susceptibility to the state parameter (ψ). Unlike prior works that approximate state dependence indirectly by randomizing shear strength, the present work models the initial state parameter (ψ_0) itself as a spatially correlated random field with a depth-dependent mean profile, reflecting depositional variability while keeping the NorSand constitutive parameters fixed. Random-field correlation lengths and anisotropy are adopted from CPTu-based spatial variability studies on tailings deposits while the NorSand parameters are calibrated against published experimental response data using an element-level implementation developed in MATLAB. The ψ_0 field is generated through Karhunen-Loève expansion and propagated through Monte Carlo effective-stress TSF stability analyses in PLAXIS 2D. Results show that ψ_0 heterogeneity creates zones with different degrees of contractive response, which leads to localized pore-pressure build-up and deformation. As a result, excess pore-pressure response and the predicted failure mechanism vary across realizations, rather than remaining confined to a single deterministic prediction. The probabilistic workflow provides a robust, data-driven pathway toward performance-based TSF assessment and strengthens mine-closure decisions for long-term stability under depositional uncertainty.
How to cite: Liu, F. and Agarwal, E.: Probabilistic TSF stability assessment using a NorSand-based random-field framework, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-21801, https://doi.org/10.5194/egusphere-egu26-21801, 2026.
The backfilling method stands as a widely employed extraction technique in contemporary mining practices, with the performance of cemented tailings backfill (CTB) being pivotal in determining the overall quality of backfilling. Nevertheless, traditional CTB exhibits suboptimal mechanical properties, particularly crack resistance, under complex stress environments. Presently, one of the extensively explored backfill types is the fiber-reinforced cemented tailings backfill (FRCTB), with a particular emphasis on those reinforced with polypropylene fibers. In order to scrutinize the mechanical characteristics of FRCTB under intricate stress states, this study, employing a triaxial Hopkinson pressure bar experimental apparatus, investigates the dynamic mechanical behaviors, fracture damage patterns, and energy dissipation features of FRCTB under five different confining pressures (0, 1, 2, 3, 4 MPa) and various strain rates. Key findings include:
(1) Under dynamic loading, FRCTB exhibits a pronounced strain rate strengthening effect along with a notable confining pressure strengthening effect. The presence of confining pressure significantly alters the stress-strain curve of FRCTB. The peak stress and dynamic increase factor (DIF) of FRCTB linearly increase with the augmentation of both confining pressure and strain rate. The peak strain linearly increases with the strain rate, with confining pressure exerting minimal influence on the peak strain. Confining pressure substantially enhances the elastic modulus of FRCTB, while the impact of strain rate is comparatively marginal.
(2) In the absence of confining pressure, FRCTB specimens, with increasing strain rates, exhibit an outward-expanding conical failure shape. The crack volume and surface area increase in a stepwise fashion, and the hollow cylindrical polypropylene fibers undergo flattened failure. At this juncture, the polypropylene fibers endure a limit strain rate ranging from 206.5 s-1 to 232.3 s-1. As confining pressure gradually increases, the outward expansion tendency is progressively restrained until no discernible internal damage occurs. At this point, the polypropylene fibers manifest phenomena such as splitting, bending, and extraction. Under low (no) confining pressure conditions, the fractal dimension and porosity of FRCTB increase with the rising strain rate. In high confining pressure conditions, the fractal dimension and porosity of FRCTB are relatively similar across different strain rates.
(3) At lower confining pressures, the strain rate strengthening effect is evident in both fracture morphology and energy dissipation but diminishes as confining pressure increases. Dissipated energy density exhibits an increasing trend with the rise in confining pressure, while the energy dissipation rate shows a quadratic function decrease with increasing strain rate. The stress-strain curves of FRCTB under no confining pressure and with confining pressure can be categorized into four and five segments, respectively: elastic growth, plastic yield, post-peak energy accumulation, and post-peak failure for the former, and elastic growth, plastic damage incubation, plastic damage development, plastic damage accumulation, and post-peak failure for the latter. Under low confining pressure conditions, the fractal dimension linearly increases with the growth of dissipated energy. This trend gradually transforms into a cubic function change as confining pressure increases. There exists a notable similarity between fractal dimension and energy dissipation rate, as well as between strain rate and confining pressure.
How to cite: Zou, S., Gao, Y., and Zhou, Y.: Study on Dynamic Mechanical Behavior and Damage Evolution Mechanism of Fiber Reinforced Cemented Tailings Backfill, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-3329, https://doi.org/10.5194/egusphere-egu26-3329, 2026.
Mining activities are a major driver of long-term geo-environmental and eco-environmental degradation, particularly during the post-mining stage when residual contamination and ecological risks often persist or intensify. The rapid expansion of lithium mining and processing linked to the battery and energy-transition industries has increased Li accumulation in soils and waters around mine sites, posing emerging risks to terrestrial ecosystems and land reclamation. Owing to its high mobility and weak natural attenuation, lithium presents particular challenges for post-mining soil remediation, highlighting the need for effective, low-cost, and ecologically compatible remediation strategies.
Here we evaluate perennial ryegrass (Lolium perenne L.) for lithium phytoremediation using a 42-day hydroponic experiment with six LiCl treatments (0, 7, 140, 280, 560, and 700 mg L-1). Plant performance was assessed through seed germination, growth traits, photosynthetic pigment contents, oxidative stress indicators, and antioxidant enzyme activities. Lithium removal and accumulation were evaluated to assess plant tolerance and remediation efficiency. Lithium exposure induced clear dose-dependent inhibitory effects on germination and seedling development, with pronounced suppression occurring at concentrations ≥280 mg L-1. Under high Li stress (560–700 mg L-1), ryegrass exhibited significantly reduced growth and photosynthetic pigment contents, accompanied by enhanced oxidative damage, indicating that prolonged and intense Li stress can disrupt physiological homeostasis. Correlation analysis further demonstrated a stress-threshold–dependent physiological shift, whereby Li accumulation was positively associated with oxidative stress indicators (MDA) and antioxidant enzyme activities (SOD, POD, and CAT) under moderate Li stress, but became negatively correlated with growth and photosynthetic parameters at higher Li levels, reflecting a transition from adaptive defense responses to toxicity-dominated inhibition. Despite these adverse effects, ryegrass maintained substantial remediation capacity across a wide concentration range. Lithium removal increased consistently with exposure time, and after 42 days, removal efficiencies exceeded 60% for all moderate-to-high treatments (280–700 mg L-1). At the highest Li concentration, maximum Li accumulation reached 38.26 mg g-1, which is significantly higher than Li accumulation levels reported for maize and sunflower under comparable conditions. Tissue partitioning indicated root-dominated Li retention, limiting translocation to shoots.
To elucidate the microscale mechanisms of Li stabilization, time-of-flight secondary ion mass spectrometry (TOF-SIMS) imaging was conducted on root cross-sections, and an ion–ion spatial correlation matrix was constructed. Lithium signals were concentrated in organic-rich microdomains near the cortex and endodermis, showing strong co-localization with oxygen-rich fragments derived from polysaccharides and phenolic structures (indicative of carboxyl and hydroxyl functional groups), as well as phosphate-related fragments. In contrast, negative spatial associations with Si-rich mineralized regions were observed, highlighting the dominance of biochemical domains rather than silicified structures in Li sequestration.
Overall, effective Li removal by perennial ryegrass is supported by root-dominated uptake and coordinated physiological regulation, with Li primarily associated with oxygen-rich organic functional groups and phosphate domains in roots, and a remediation threshold around 280 mg L-1. These findings provide both quantitative performance metrics and mechanistic evidence supporting the application of ryegrass-based phytoremediation for Li-mining and Li-industrial soil pollution, and they offer practical guidance for developing scalable remediation strategies at post-mining sites.
How to cite: Zhang, Y. and Chen, N.: Lithium Uptake, Physiological Responses, and Root-Scale Stabilization Mechanisms in Perennial Ryegrass, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-2495, https://doi.org/10.5194/egusphere-egu26-2495, 2026.
Potassium (K) is an essential nutrient for all living organisms. Its high mobility in soils often limits its availability to plants, constraining growth. To meet the increasing demand for food, K-based fertilizers are routinely applied to enhance the yields of agricultural crops. However, the use of conventional KCl fertilizers can lead to soil salinization, their supply is vulnerable to geopolitical and economic fluctuations, and the production of soluble KCl is energy- and environmentally intensive. Therefore, potassium-rich aluminosilicate minerals, such as micas, glauconite, and K-feldspar, have been considered as alternative potassium fertilizers. This study investigates the usability of mining waste composed of glauconitic sandstone as a raw material for potassium fertilizer, with a focus on mechanical activation as a method to enhance potassium leachability. Bulk sandstone and enriched glauconite samples were subjected to mechanical activation to evaluate changes in particle size, morphology, specific surface area, and potassium solubility. Mechanical activation significantly enhanced the release of plant-available K, with up to 80% of total K released into solution in 240 minutes, with 55% of K extracted in first 30 minutes, indicating high process efficiency. Glauconite sandstone enrichment improved the K content by 14% but also led to a nearly seven-fold increase in bulk Cr concentrations reaching 291 ppm, approaching regulatory limits for fertilizers agricultural use. While mechanical activation offers a scalable, energy-efficient alternative to conventional K-fertilizers, the relatively low bulk K₂O content (<5%) and elevated Cr levels limit the practical application of the Estonian glauconitic sandstone as a K-fertilizer. These findings highlight both the potential and constraints of mechanical activation for sustainable potassium fertilizer production.
How to cite: Pihel, R., Lumiste, K., Kirsimäe, K., and Paaver, P.: Mechanically activated glauconitic sandstone: potential for alternative potassium fertilizer, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-4895, https://doi.org/10.5194/egusphere-egu26-4895, 2026.
Mining activity is essential for providing the raw materials necessary for societal development. The life of an underground mine depends on multiple factors, such as geological characteristics (e.g., mineral quantity and quality), economic drivers (costs, market prices, technology), technical constraints (e.g., extractive efficiency), and environmental/social considerations (e.g. regulations, impact). Following closure, multiple processes can occur, such as subsidence, slope instability, uplift, and the flooding of galleries. Therefore, continuous monitoring of abandoned mines is essential to mitigate risks to human safety and infrastructures. Some abandoned mines are repurposed for uses such as underground tourism, gas storage, fungi cultivation or geothermal resources, among others. The Candín-Fondón underground coal mine is located in the Nalón River valley in Langreo (NW Spain). Coal extraction in the region began in 1840 at the La Nalona mountain mine, later transitioning to the deep-shaft mining complexes of Fondón and Candín. The Fondón shaft reached a depth of 667 m and remained operational until 1995, while the Candín complex reached depths of up to 717 m. During the exploitation of the mines, groundwater levels dropped by more than 600 m in some areas. Today, these sites have been repurposed for industrial heritage and geothermal energy production (up to 3.488 MWh) using mine groundwater. Consequently, the groundwater level in the galleries has gradually recovered. However, the recovery of groundwater levels to the design level for geothermal exploitation has led to an increase in pore pressure within the rock mass joints, causing rock mass expansion and subsequent ground surface uplift. This uplift was detected using European Ground Motion Service (EGMS) Synthetic Aperture Radar Interferometry (InSAR) datasets for the period 2015–2021. Positive uplift rates exceeding 10 mm/year and accumulated uplift of over 4 cm were measured. These displacements are concentrated mainly over the mining works of Candín and Fondón, with maximum displacements located near the Fondón mine shaft. The InSAR time series shows a clear sigmoidal evolution of positive displacements starting in 2016, increasing until 2019, and then stabilizing. EGMS datasets from 2019–2023 show stabilization with residual uplift rates below 2 mm/year. Therefore, this work presents an example of how high-resolution InSAR datasets, such as the EGMS, can be used to accurately characterize the non-linear surface response to groundwater rebound in abandoned mines repurposed for geothermal energy.
How to cite: Tomás Jover, R., Álvarez-Fernández, I., González Nicieza, C., and Alejano, L. R.: Monitoring ground uplift in an abandoned mountainous coal mine converted to geothermal facilities using Synthetic Aperture Radar Interferometry (InSAR), EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-19082, https://doi.org/10.5194/egusphere-egu26-19082, 2026.
San Quintín was a former galena (PbS) mine rich in Ag, and sphalerite (ZnS), whose extractive activity generated a set of mining wastes with high contents of heavy metals and metalloids, mainly present as primary sulfides and secondary sulfates, accompanied by significant amounts of pyrite (FeS₂). These wastes pose an environmental risk due to their dispersion into the surrounding natural environment. The presence of sulfides, such as pyrite, promotes the formation of acid mine drainage (AMD), generating waters with low pH and high electrical conductivity (EC).
The objective of this study was to assess the quality of water in streams and ponds in the San Quintín area through physicochemical parameters (pH and EC) during the restoration stage, comparing them with values obtained prior to the remediation actions. To this end, a network of sampling points was established along the stream system and in rain-formed ponds, prioritizing areas close to former waste rock dumps and tailings. Measurements were carried out both in situ and in the laboratory using calibrated equipment, allowing detailed monitoring of the physicochemical variability of temporary surface waters.
The results indicate that under drought conditions, which represent the critical load of acidity and ion concentration, partial recovery of pH and EC is observed in sectors associated with old ponds and waste rock dumps. During the rainy season, pH increases markedly due to dilution, while EC decreases near the deposits but increases at the confluence points of the stream system, where ions transported by runoff become concentrated.
As a provisional conclusion, considering the factors affecting the variability of physicochemical parameters, a partial recovery of pH and EC is observed in the temporary surface water system of the mining area, largely attributable to the neutralizing action of carbonate materials deposited during restoration. Nevertheless, continued monitoring of these parameters is still necessary to verify that conditions of near neutrality are ultimately achieved in the waters throughout the area.
How to cite: Bakale, F., Jaeger Collantes, J. L., Nsue Eneme, M. T., Obama Ntutumu, D. M., Morales Laurente, J. A., Barquero Peralbo, J. I., and Higueras Higueras, P. L.: Monitoring of surface water quality in the San Quintín mining area during its restoration, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-6954, https://doi.org/10.5194/egusphere-egu26-6954, 2026.
In deep hard-rock rotary–percussive drilling, energy efficiency is often constrained because only a fraction of the input energy is converted into effective volumetric fragmentation. The combined action of high-frequency impacts and bottom-hole rotational loading promotes localized crushing, excessive fines generation, and non-directional crack growth, so the crack network fails to evolve into a dominant fracture system capable of effectively detaching rock fragments; instead, substantial energy is dissipated through secondary crushing and high-frequency vibration, yielding only marginal gains in fragmentation while increasing the risk of borehole-wall damage. To address this limitation, the present study relates drilling efficiency to bottom-hole fracture modes by clarifying how crack connectivity and propagation mechanisms govern effective breakage work. A coupled tooth–rock stress-field and fracture-evolution framework is developed to systematically evaluate how tooth geometry, cutter layout, and operational parameters steer crack-network development, and an energy-based metric is formulated to interpret trends in specific energy. The framework is validated against laboratory experiments and dynamic numerical simulations using cuttings size distribution, energy consumption, and borehole-wall damage as verification targets; based on the validated model, practical design and operating windows are identified to increase the fraction of effective breakage work and provide actionable guidance for high-efficiency drilling.
How to cite: Zhang, Y.: Crack Propagation and High Efficiency Rock Fragmentation Mechanisms in Rotary Percussive Drilling, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-11908, https://doi.org/10.5194/egusphere-egu26-11908, 2026.
Quarrying activities have significant impacts on the human and the natural environments. Following a quarry's closure, exposed surfaces remain vulnerable to wind erosion and dust emission until full long-term reclamation is achieved. The objective of this research is to examine the efficacy of using quarry by-product material (Nivrar) to fill such surfaces in inactive quarries to prevent erosion until full rehabilitation takes place. This pilot research is conducted in a calcareous quarry. The fill sample consists of Nivrar supplemented with a local topsoil from the edge of the quarry to enrich it with seeds of native vegetation. Additionally, a biopolymer is used to stabilize the upper layer for immediate-term protection. Samples of the Nivrar and the topsoil were analyzed at various ratios to determine the optimal composition related to erosion and soil fertility, including aggregation, organic matter, dust fraction, electrical conductivity. A controlled experiment was performed to test seed germination and growth within the Nivrar. Experiments in a boundary-layer wind tunnel allowed for testing the samples' resistance to soil erosion and dust emission (PM). The results indicate that the Nivrar material is not a limiting factor for plant development, and its wind erosion coefficients are relatively low compared to the quarry's surfaces despite the relatively high amount of dust fraction. The addition of the topsoil increased the percentage of organic matter and essential elements (potassium). The polymer application significantly reduces dust emissions. The research results to date demonstrate the potential for implementing this method in the field as a sustainable ecological-environmental solution for the rehabilitation of inactive quarries until full reclamation is achieved.
How to cite: Esther, A., Ben-Hur, M., and Itzhak, K.: Preventing dust emission in non-active quarries by filling enriched waste material, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-8067, https://doi.org/10.5194/egusphere-egu26-8067, 2026.
Coal wastes deposited in heaps may undergo self-heating and spontaneous combustion processes. Under oxygen-limited conditions in the dump, besides burning, pyrolysis processes occur. Both processes (pyrolysis and oxidation) result in emissions of volatile pollutants and have been developed in several heaps in the Upper Silesian Coal Basin (USCB), where coal exploitation has lasted for over a century.
To examine the molecular composition and yields of volatile compounds produced during self-heating, in relation to organic matter (OM) content and its maturity, mineral matter composition, temperature, water presence and oxidation conditions, four coal waste samples were collected from the Polish part of the USCB: two from the Janina Mine (JAN-1, JAN-2) (Rr ca. 0.5%) and two from the Marcel Mine (MAC-1, MAC-2) (Rr ca. 0.9%). JAN-1 and MAC-1 are siltstones containing more quartz and less OM than JAN-2 and MAC-2 claystones. Results of the Rock-Eval analysis evidenced 1.8, 27.3, 1.9, and 21.4 wt. % TOC, respectively and the presence of the Type-III kerogen in all samples. Simulations of the self-heating were conducted in 1-L closed reactors in conditions: dry pyrolysis (DP), hydrous pyrolysis (HP) in 250, 360, and 400oC for 72 h, and oxidation with air (OXI) in 250 and 400oC for 72 h.
The molecular composition of generated gases (i.e., HCs (C1-C8), CO, CO2, H2, H2S, organic S-compounds) was determined and then re-calculated as yields, taking into account the amount of gas generated (pVT) and the mass and TOC of the rock used for each experiment.
The concentration of HCs in HP and DP runs increases with temperature increase up to 58.4 mol %. The concentrations of other generated gases in these experiments strongly relate to the temperature increase of the process as well: the concentration of CO decreased, and the concentration of CO2, H2, H2S and organic S-compounds increased. The presence of water and elevated TOC amounts boost the generation of S-compounds (dominated by H2S). During all OXI experiments, only traces of HCs, H2 and S-compounds were produced; the concentration of CO2 increased and CO decreased with experiment temperature increase. Gases generated from TOC-rich rocks are richer in HCs, and organic S-compounds, resulting in yields of these gases, up to 4.3 kg/Mg rock and 1.4 g/Mg rock, respectively. The highest CO2 and CO yields were recorded in OXI experiments, reaching approximately 390 and 20 kg/Mg rock, respectively; in pyrolytic experiments, these yields did not exceed 8.4 and 0.15 kg/Mg rock, respectively. After recalculating the gas yields per TOC mass in waste, it appeared that the highest HCs yields, exceeding 20 kg/Mg TOC, were recorded during HP and DP pyrolysis at 400°C of samples poor in organic carbon. CO2 and CO yields are highest in OXI experiments of the above-mentioned samples, reaching 850-2000 and 10-50 kg/Mg TOC, respectively. The yields of these gases in pyrolysis experiments for these samples reach 24-310 kg/Mg TOC and 0.0-1.3 kg/Mg TOC, respectively.
This study was financed from the AGH University of Krakow research subsidy (16.16.140.315) and the National Science Centre, Poland, grant No 2017/27/B/ST10/00680.
How to cite: Więcław, D., Bilkiewicz, E., Jurek, K., Fabiańska, M., Ciesielczuk, J., and Misz-Kennan, M.: Assessment of factors influencing the composition and yield of gases emitted during the self-heating of coal waste based on laboratory simulations, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-17007, https://doi.org/10.5194/egusphere-egu26-17007, 2026.
Opencast coal mining lastingly alters the landscape and hydrology of impacted regions, such as the Lusatian lignite mining district in Eastern Germany. As mining operations are being phased out, groundwater recharge leads to an increased exfiltration of iron- and sulphate-containing compounds into surface waters where they precipitate as iron hydroxide sludge (IHS). These processes occur either under natural conditions or induced through specific technical water treatment interventions. Thus, approximately 60,000 tons of IHS accumulate in Lusatia annually, which currently must be disposed of at great expense to the local authorities, due the absence of viable recycling solutions. Depending on the specific location and precipitation context, IHS can vary greatly in terms of their chemical and mineralogical composition. Initial applied research suggests that there is great potential for using iron-rich, fine-textured and, in some cases, organic-rich IHS in soil amelioration, aiming to stabilise soil carbon, improve water retention capacity and nutrient storage. Respective positive effects are particularly relevant for the restoration/improvement of sandy post-mining soils, prevalent in Lusatia. However, since some IHS are associated with potentially toxic elements, a detailed characterisation of these mineral residues is necessary to determine their suitability for potential uses. As part of the European Centre of Just Transition Research and Impact-Driven Transfer (Project: CO₂-Sequestration and Soil Recultivation Through Recycling of Mineral Residues), we are presenting a comprehensive geochemical and mineralogical systematisation of Lusatian IHS, relying on data derived from RFA, XRD, XPS, 57Fe Mössbauer spectroscopy, wet chemical extractions, and BET surface area measurements. The high geochemical and mineralogical diversity of IHS, even across short geographical distances, is highlighted by the range of exemplary key parameters such as pH (2.1–7.7), total S content (0.1–3.0 %), Dithionite-Citrate-Bicarbonate-extractable iron Fed (124.1–388.4 mg/g), Oxalate-extractable iron Feo (63.0–322.6 mg/g), and Feo/Fed ratio describing the degree of crystallinity of the iron phase (0.16–1.0). This data from Lusatia is contextualized with published (inter)national case studies, and perspectives for the use of specific IHS types in soil amelioration are critically discussed.
How to cite: Herrmann, J., Harlow, E., Pohl, L., Mikutta, R., and Stein, M.: Iron hydroxide sludges from the post-mining landscape of Lusatia, Germany: Prospects for their application as soil ameliorant based on geochemical and mineralogical characteristics, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-9925, https://doi.org/10.5194/egusphere-egu26-9925, 2026.
Posters virtual: Tue, 5 May, 14:00–18:00 | vPoster spot 4
EGU26-6952 | ECS | Posters virtual | VPS19
Pumped‑Storage Hydropower in a Post‑Mining Landscapes: A Feasibility Study for Repurposing the Ptolemaida Lignite Basin in Western Macedonia, GreeceTue, 05 May, 14:09–14:12 (CEST) vPoster spot 4
How to cite: Touloumenidou, L.: Pumped‑Storage Hydropower in a Post‑Mining Landscapes: A Feasibility Study for Repurposing the Ptolemaida Lignite Basin in Western Macedonia, Greece, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-6952, https://doi.org/10.5194/egusphere-egu26-6952, 2026.
EGU26-4291 | Posters virtual | VPS19
Coal fire & Mine water: two major post-mining issuesTue, 05 May, 14:12–14:15 (CEST) vPoster spot 4
Coal is an important major source of energy for sustainable development and growth of economy around the world. Coal fire and mine water issues are two aspects of mining-induced safety and eco-environmental issues which occurred during and after mining. In the present presentation, the author illustrates the understanding of these two issues by employing the theoretic analysis, the experimental simulation, the numerical simulation, and the field investigation, etc. Results from this research show that the rational scientific mining methods and technologies can be used to reduce the occurrence and influence of these two phenomena which leads to the possible sustainable exploitation of coal resource.
How to cite: Zeng, Q.: Coal fire & Mine water: two major post-mining issues, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-4291, https://doi.org/10.5194/egusphere-egu26-4291, 2026.
EGU26-7832 | ECS | Posters virtual | VPS19
Managing Pyrite-Rich Tailings: A Greenhouse Study on Vegetation and Microbial Responses to Thin Soil CapsTue, 05 May, 14:15–14:18 (CEST) vPoster spot 4