Key topics of interest include:
(i) Geotechnical aims: stability and deformation monitoring, erosion modelling, water balance, and moisture mapping.
(ii) Environmental aims: water pollution/acid mine drainage, dust and aerosols, vegetation health monitoring, and ecosystem recovery.
(iii) Valorisation aims: re-mining/re-processing case studies that link EO-derived composition/proxies to processing options for secondary CRM recovery.
We particularly encourage interdisciplinary contributions that combine Earth observation with advances in artificial intelligence, database development, and frameworks for circular economy and energy transition. By linking technical monitoring with societal, economic, and policy perspectives, the session aims to advance holistic approaches for managing risks and unlocking the resource potential of mine waste.
Orals: Wed, 6 May, 10:45–12:30 | Room -2.43
Mining, particularly gold extraction, represents a significant economic sector but also causes substantial environmental impacts through mine-influenced water (MIW). This contaminated water, especially acid mine drainage (AMD), poses a serious threat to the quality of surface and groundwater and adversely affects both human health and ecosystems. In countries such as South Africa, which are heavily reliant on mining and simultaneously face water scarcity, MIW presents a complex and pressing challenge. The research project MAMDIWAS (Mine Water as a Driver for Change to Enhance Water Security in South Africa), adopts an integrative, technology-based approach to the sustainable utilization of MIW. The project aims to reconceptualize MIW as a resource that can be harnessed for drinking water supply, agriculture, and raw material recovery. At this stage it focuses on integrated water resources management, i.e. (i) assessing water quality within the catchment area of mines, (ii) identifying key pollutants originating from MIW and evaluating their toxicological effects, and (iii) exploring reuse options and analyzing public acceptance, with the goal of deriving informed strategies for water protection and resources management.
Two sampling campaigns were conducted in 2024 and 2025 along two rivers downstream of gold mines west of Johannesburg, as well as on the premises of an active gold mine. The collected samples were analyzed in the laboratory for heavy metals (including Al, Sr, Fe, Mn, Pb, Cd, Co, Cr, Cu, Ni, Zn, Mo, V, Si, Ar, U) and other relevant parameters. The campaigns were carried out under both normal and low-flow conditions. In addition, in-vitro toxicity tests were performed to assess mutagenic and genotoxic effects. The overarching objective is to evaluate ecological and health risks associated with MIW, particularly in regions where such water is used for drinking or irrigation, thereby laying the foundation for sustainable water management. First results indicate that local conditions influence the occurrence and toxicity of MIW pollutants, e.g. geological settings and climate seasonality. Furthermore, samples taking downstream from mining sites show that MIW pollution concentrations are declining due to dilution, sorption, and degradation. However, at the same time toxicity analyses feature an increase further downstream. A working hypothesis that additional pollutants from formal and informal settlements of mostly mine workers influenced this increase was confirmed by additional analysis of organic pollutants. As a next step water re-use options for these different MIW qualities will be derived.
How to cite: aus der Beek, T., Gimbel, K., Truter, C., and Carstens, A.: Between risk and resource – Mine-Influenced Water (MIW) as challenge and opportunity, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-12497, https://doi.org/10.5194/egusphere-egu26-12497, 2026.
Ongoing transformations in the European raw materials sector have accelerated the decline of coal mining and the closure of mines across Europe. This process gives rise to post-mining areas, the environmental impact of which does not end with the end of exploitation. In this context, the ability to predict environmental risks at an early stage, based on analyses carried out on similar sites is crucial. Among the various post-mining features, thermally active coal waste dumps represent a persistent environmental legacy of historical and contemporary coal mining. At these sites, spontaneous combustion and self-heating processes can remain active decades after mine closure as a result of exothermic reactions in coal residues and organic matter. These processes generate long-term thermal anomalies, gas emissions, and progressive degradation of soils and ecosystems. Monitoring such sites is therefore essential for understanding associated risks and tracking long-term changes in thermally active areas, with direct relevance for post-mining land use and reclamation process.
This study presents an Earth Observation (EO)-based approach for acquiring and analysing Land Surface Temperature (LST) to monitor thermally active coal waste dumps and evaluate their relationship with surface and vegetation conditions. The methodology is based on multi-temporal open-access satellite imagery, enabling the detection of both persistent and seasonal thermal anomalies at local scales while supporting long-term environmental analysis at the regional level. The analysis uses Landsat 5, 8, 9 imagery acquired between 1999 and 2025 and focuses on a thermally active coal waste heap near Nowa Ruda in the Lower Silesian Coal Basin (SW Poland), a region transformed by decades of underground coal mining.
Thermal anomalies were mapped and analysed across multiple time steps to assess their spatial patterns and temporal variability. The Self-Heating Intensity Index (SHII) was calculated to quantify the intensity and persistence of thermal activity within post-mining waste materials. LST data were analysed in conjunction with vegetation and surface condition indicators derived from satellite imagery, including NDVI, SAVI, NDMI, NBR and BSI. To understand how thermal patterns and surface condition indicators interact under different moisture and geomorphological conditions at waste dumps, a combination of spatial correlation analyses and seasonal comparisons were used.
The results demonstrate spatial associations between elevated LST values and surface characteristics indicative of limited vegetation cover and exposed substrates, whereas areas with lower thermal signatures correspond to more developed surface cover. Temporal analysis reveals differences in the seasonal behaviour of thermal and spectral indicators, allowing for the differentiation of zones with contrasting thermal and surface conditions.
To address the persistent environmental impacts of coal mining in the context of ongoing transformations in the energy and raw materials sector, this study applies thermal and spectral data obtained from satellites to monitor thermally active mine waste sites. The results can serve as a reference point for risk assessment in other areas undergoing mine closure, as well as providing insight into potentially dangerous phenomena based on experience from areas with a longer history of post-mining transformation.
How to cite: Romańczukiewicz, K., Górniak-Zimroz, J., and Blachowski, J.: Satellite Monitoring of Thermally Active Coal Waste Dumps in the Lower Silesian Coal Basin – Nowa Ruda mine study, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-19904, https://doi.org/10.5194/egusphere-egu26-19904, 2026.
Mining operations are generally accompanied by mobilization of various contaminants that are transferred via water or air to various environmental compartments such as soil, sediments, or biota. Understanding their origins, trajectories, sinks, and spatial distribution is essential for effective risk assessment, site management, recovery planning, and transparent communication with regulators and communities. Rosia Poieni, a porphyry copper deposit that has been excavated as an open-pit mine for the past five decades, has been selected as a test site to integrate remote sensing and ground observation methods for assessing the environmental conditions in the mining and surrounding areas in the EU-funded MOSMIN project. The abundance of pyrite in the host rocks favours the generation of severe acid mine drainage, resulting in pH levels ranging from 2 to 3 and a high load of heavy metals in the streams emerging from the waste rock dumps.
A combination of satellite and UAV multispectral and hyperspectral data, and targeted ground truthing (mineralogical, geochemical, and spectroscopic analyses) has been used to acquire validated and interoperable data products that delineate contaminant sources, transport pathways, and accumulation zones across terrestrial, fluvial, and atmospheric compartments.
Hyperspectral satellite data from PRISMA and EnMAP enabled the discrimination of alteration assemblages and secondary mineral phases that control acid mine drainage (AMD) processes and associated metal release. When supported by site-specific spectral libraries derived from hyperspectral scanning of hand specimens, supervised spectral unmixing approaches produced mineralogical maps with a high degree of consistency relative to field observations and laboratory XRD results. These outputs allow the differentiation of alteration facies with contrasting environmental relevance, such as pyrite-rich phyllic and argillic materials with high acid-generating potential versus propylitic and potassic assemblages characterised by greater buffering capacity.
Multispectral satellite data, particularly from Sentinel-2, were shown to be essential for spatial and temporal scaling of hyperspectral results. Sentinel-2 band ratios and mineral proxy indices, despite their limited spectral resolution, provided robust first-order indicators of iron oxidation state, hydroxyl-bearing alteration, and AMD-impacted materials.
At the local scale, UAV-based multispectral and hyperspectral imaging proved critical for resolving AMD distributions in narrow drainage corridors and near-field impact zones that are not adequately captured by satellite sensors.
The implemented workflows show that we can advance EO-based contaminant assessment from qualitative mapping to quantitative, validated, and reproducible information products. The integration of multiple sensors ensures internal consistency across spatial scales and establishes a robust technical foundation for subsequent data fusion and modelling activities.
Acknowledgement: This work was financially supported by the European Union Agency for the Space Programme under Project 101131740—MOSMIN—HORIZON-EUSPA-2022-SPACE.
How to cite: Baciu, C., Kirsch, M., Gloaguen, R., Booysen, R., Tamas, C., Kerekes, A.-H., Costin, D., Radovici, A., Nita, D.-C., Botezan, C., and Pavel, N.: A multiscale observational approach for tracking AMD from source to sink: application to Rosia Poieni copper mine, Romania, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-14221, https://doi.org/10.5194/egusphere-egu26-14221, 2026.
Legacy mine wastes have accumulated over centuries in regions such as Benguet, Philippines, and Cornwall, United Kingdom. Inefficient historical processing left valuable metals in these materials, supporting their potential role in a circular economy through secondary resource recovery. However, elevated concentrations of toxic metals such as arsenic also pose long-term environmental risks. This dual character highlights the need to evaluate legacy mine wastes not only as potential secondary metal resources but also as sources of environmental liability.
Studying legacy mine wastes presents several challenges. These materials are often highly heterogeneous, vary significantly across short spatial scales, and are often poorly documented in terms of their composition, emplacement, and subsequent alteration. Furthermore, intrusive investigations can disturb legacy wastes and mobilise toxic metals, while conventional methods such as drilling are costly, invasive, and limited in coverage. In contrast, geoelectrical techniques provide a non-invasive and cost-effective way to characterise the internal structure and hydrogeological behaviour of mine wastes over larger areas, and are therefore applied in this study to investigate legacy tailings at the Padcal–Philex mine in Benguet, Philippines, and at Wheal Maid (WM), as well as legacy waste rock deposits at Binner Downs (BD) in Cornwall, UK.
At the Padcal–Philex site, several arrays of PRIME electrical resistivity monitoring equipment were installed along and across Benches 4 and 5 of Tailings Storage Facility 1 (TSF1) to characterise the hydrogeological behaviour of the tailings. Daily measurements collected between April 2023 and May 2024 demonstrate that electrical resistivity tomography (ERT) can effectively monitor moisture dynamics within the tailings during both monsoon and dry seasons, a key factor in assessing tailings stability and in planning future secondary resource recovery. Further data processing shows that ERT can distinguish between muddy and sandy tailings units, which have different average copper content, validated by auger sampling.
At Wheal Maid, ERT surveys were conducted along multiple profiles in July 2024, May 2025, and September 2025 to investigate acid mine drainage (AMD) processes in the lower lagoon area. The resistivity models reveal zones of persistently low resistivity, interpreted as areas influenced by AMD within the lagoon. These low-resistivity zones may indicate seepage of AMD-rich water beneath the tailings and tailings dam, suggesting pathways for contaminant transport to the downstream River Carnon. At Binner Downs, ERT imaging successfully delineates the boundary between legacy waste rock and the original ground surface, improving understanding of waste distribution and thickness.
Overall, these results demonstrate the value of geoelectrical techniques for investigating legacy mine wastes. By enhancing understanding of subsurface heterogeneity, moisture behaviour, and contaminant pathways, geoelectrical techniques provide a non-intrusive framework to support environmental risk assessment, remediation planning, and the evaluation of targeted reprocessing opportunities in legacy mining landscapes.
How to cite: Gibaga, C. R., Swift, R., Jenkin, G., Chambers, J., Crane, R., Marquis, E., Kuras, O., Horabin, C., Gervasio, J. H., Tanciongco, A., Quierrez, R. N., Harrison, H., Ngui, J., Porter, J., Bruce, E., Samaniego, J., and Arcilla, C.: Imaging Legacy Mine Wastes: Geoelectrical Characterisation of Tailings and Waste Rocks in the Philippines and the UK, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-8206, https://doi.org/10.5194/egusphere-egu26-8206, 2026.
Abandoned mining areas often constitute complex environmental systems, with large volumes of waste materials remaining exposed and poorly documented. In many historical mining districts, the lack of reliable information regarding the amount and spatial distribution of these wastes makes it difficult to properly assess environmental impacts and to define adequate remediation strategies. Recent developments in unmanned aerial vehicle (UAV) technology offer practical solutions to overcome these limitations, particularly in difficult-to-access areas where conventional surveying methods may be limited.
This study presents a UAV-based photogrammetric methodology for the quantitative assessment of mining waste deposits in data-scarce environments, with the primary objective of demonstrating the applicability of high-resolution aerial surveys as a general tool for environmental characterization and decision support. The approach integrates UAV-acquired imagery with photogrammetric processing to generate detailed orthophotos and digital surface models (DSMs), enabling accurate three-dimensional reconstruction and volume estimation of waste materials.
The methodology is applied to an abandoned mining area within the Iberian Pyrite Belt, a region historically affected by intensive sulfide mining and associated environmental impacts, which is used here as a representative case study. High-resolution, georeferenced imagery was acquired using a DJI Phantom 4 RTK UAV and processed to delineate waste accumulation zones, analyze surface morphology, and calculate waste volumes in the absence of detailed archival records.
The results demonstrate that UAV-derived products provide a robust representation of waste deposit geometry, supporting quantitative assessments relevant to environmental risk evaluation and management planning. Beyond volume estimation, the generated datasets provide a valuable spatial baseline for future monitoring of geomorphological changes driven by erosion, instability, or remediation actions.
Overall, the study highlights the potential of UAV-based photogrammetry as a versatile and transferable approach for addressing data limitations in abandoned mining areas and other environmental contexts where legacy waste characterization is required. The proposed framework supports informed decision-making and contributes to more effective environmental management and restoration strategies.
How to cite: Barroso, A., Henriques, R., Cerqueira, Â., Gomes, P., Horta Ribeiro, I. M., Marinho Reis, A. P., and Valente, T.: Overcoming Data Gaps in Abandoned Mining Areas Through High-Resolution UAV Surveys, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-22627, https://doi.org/10.5194/egusphere-egu26-22627, 2026.
The northern zone of the abandoned Sb–As–Tl–Au Allchar deposit in North Macedonia is characterized by high concentrations of thallium (Tl), iron (Fe) and arsenic (As), which are distributed among mining waste, technosols and soils (Đorđević et al., 2021; Vaňek et al., 2024). The high concentrations of Tl and As in carbonated, buffered environments have led to the formation of secondary minerals that are more widespread than is currently documented, and which can play an important role in reducing the dispersion of Tl and As from sources of contamination. Therefore, a detailed mineralogical assessment of Tl- and As-rich legacy tailings is important to understand the environmental risks and inform future strategies for the valorization or containment of these materials within a circular economy framework.
As part of the current study, we have begun investigating orpiment-rich tailings near Adit 25 in the northern part of the Allchar deposit. Tailings material was collected at four different areas of the tailings and bulk chemical, and mineralogical analyses were performed using powder X-ray diffraction (PXRD), Raman spectroscopy and inductively coupled plasma mass spectrometry (ICP-MS).
The preliminary results indicate the following: (i) Tl is present in amounts ranging from 210 to 3,950 ppm, with an average value of 2,035 ppm; (ii) As is present in amounts ranging from 6,750 to 210,000 ppm, with an average value of 124,550 ppm; (iii) Fe is present in amounts ranging from 6,500 to 50,500 ppm, with an average value of 34,700 ppm. Locally the samples show elevated concentrations of Sb (up to 1,150 ppm) and Hg (up to a maximum of 500 ppm). The main sources of As are orpiment (As2S3), locally realgar (As4S4) and scorodite (FeAsO4·H2O), followed by minor Fe-sulfate arsenates (e.g. bukovskyite, Fe3+2(AsO4)(SO4)(OH)·9H2O) and calcium arsenates. The main sources of Fe are pyrite (FeS2), marcasite (FeS2), goethite (Fe3+O(OH)), scorodite and amorphous Fe-oxides, as well as minor Fe-sulfate arsenates. The major sources of Tl are Tl-bearing sulfosalts, such as vrbaite (Hg3Tl4As8Sb2S20) and simonite (TlHgAs3S6), which also serves as the sources of antimony (Sb) and mercury (Hg). Further dominant phases are gypsum, dolomite, quartz, calcite, muscovite and kaolinite, and barite in the heavy fraction (density >2.9 g/cm3).
While the present study is based on bulk chemical and mineralogical analyses, ongoing and planned micro- and nano-scale electron microscopy will extend these results by investigating metastable surface phases containing Tl and As, thereby improving the assessment of selective re-mining, containment, and valorization options for hazardous but resource-bearing mine waste within risk-aware circular economy frameworks.
Financial support of the Austrian Science Fund (FWF) [P 36828-N] to T. Đorđević is gratefully acknowledged.
Đorđević, T. et al. (2021): J. Appl. Geochem., 135, 105114–105130.
Vaňek, A. et al. (2024): Environ. Pollution, 357, 124413–124421.
How to cite: Lammer, N. and Đorđević, T.: Mineralogical assessment of orpiment-rich tailings from the abandoned Allchar mine, North Macedonia, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-7665, https://doi.org/10.5194/egusphere-egu26-7665, 2026.
Our world is highly dependent on advanced technology, which places a heavy demand on mineral resources, although they produce large volumes of waste. Regarding non-finite mineral resources, mining waste can now be considered a valuable secondary resource. However, they can also be a potential source of pollution. Large heterogeneities in mineralogical compositions and physical and chemical properties make remediation solutions highly complex.
In France, the remediation of mining residues is always challenging due to the aforementioned issues. The age of the mine heaps, dating back to antiquity and extending to the end of the 20th century — and the widespread distribution of the waste, contribute to investigate how a non-remediated site (W district - French Massif Central) evolved over time.
This study primarily examines the formation of new minerals resulting from the weathering of mining waste and their significance in natural attenuation processes. Of particular interest are hardpans - indurated iron layers - due to their recognized ability to effectively sequester metal(loid)s. These hardpans develop from the weathering of sulfide-rich phases in mining waste, especially arsenic-rich pyrite. Beyond W, our analysis includes other trace elements present in the waste, such as As, known for its toxicity, and Bi, whose geochemical behavior and toxicity remain poorly understood. Notably, all three elements are designated as critical raw materials.
This work seeks to elucidate the in-situ formation of hardpans and their capacity to retain critical and/or potentially toxic trace elements over the long term, with a particular focus on the sub-micron scale processes. To achieve this, we employed a multiscale approach integrating synchrotron-based XRF and XANES spectroscopy. By analyzing the As, Bi, Fe, S, and W absorption edges, we aim to characterize the speciation and redistribution of these elements following weathering processes.
The mineralogical composition of the various wastes present on site was determined, with a focus on hardpans, as well as the fractionation of metal(loid) elements within the mining waste. Crystal chemistry, substitutions, and competitive effects between ions were studied within metal-bearing phases, particularly sulfates and iron oxides, using natural and synthetic samples. The results provide an overview of the trace elements' new distribution and give insights into the weathering of mineral phases. It also helps in understanding the elemental mobility toward various environmental compartments in the surrounding area.
How to cite: Grypaiou Iskenteridou, G., Courtin, A., Paineau, E., Schoeder, S., Tranchant, L., Vantelon, D., Rivard, C., Bollaert, Q., Léger, E., Nouet, J., Plautre, A., Bereksi, M., Joussein, E., and Rouzière, S.: Multi-scale synchrotron study of critical-metal phases by XRF and XANES spectroscopies, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-960, https://doi.org/10.5194/egusphere-egu26-960, 2026.
The extraction of potassium salts produces large quantities of solid residues, consisting primarily of sodium chloride and, to a lesser extent, magnesium sulfate, magnesium chloride, and insoluble clay minerals. These saline residues have been deposited on the Earth's surface, forming potash tailings piles that can reach heights of up to 200 meters. In Central Germany, numerous potash waste piles characterize the landscape and are particularly noticeable due to their striking appearance and the usually complete absence of vegetation. When rainwater comes into contact with saline residues, sodium chloride in particular can be dissolved and mobilized. This saline seepage can penetrate the subsurface and reach the groundwater. This poses a risk of salinization of the surrounding aquifers and the impairment of surface waters and adjacent ecosystems. Soil coverings with protective vegetation are a potential measure to reduce contact between rainwater and saline residues. The aim of this research is to assess the efficiency of different vegetation types in order to minimize the negative impact of infiltrated rainwater on groundwater. This is investigated using the numerical simulation software Advanced Terrestrial Simulator (ATS), which enables the coupling of surface and subsurface flow as well as the modeling of evapotranspiration. Results indicate that care must be taken in the definition of the free-outflow boundary condition of the drainage layers. Results also show that vegetation types with a deep root zone and a high Leaf Area Index are most suitable as efficient vegetation cover.
How to cite: Graf, T. and Silva Monsalves, F. E.: Efficiency of Vegetation Types on Rainwater Infiltration of a Hypothetical Potash Tailings Pile – Results and Recommendations from a Modelling Study, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-16900, https://doi.org/10.5194/egusphere-egu26-16900, 2026.
Iron tailings, with large quantities and low utilization rates, pose significant environmental challenges. The potential for utilizing these tailings is closely linked to their pozzolanic activity. Previous studies have used saturated lime solution method to evaluate the pozzolanic activity of materials. However, the solution preparation is complex and the test time is too long. In this study, a new NaOH solution method was proposed to characterize the pozzolanic activity of iron tailing powders using electrical conductivity. The test parameters, including NaOH concentration, iron tailing powder mass, and reaction temperature, were optimized. A difference between the new proposed NaOH solution method and the traditional saturated lime solution method was compared. The feasibility of the proposed method was further verified through the strength activity index method. The results indicated that under optimal conditions (0.4M NaOH solution, 12g iron tailings powder, and 40°C reaction temperature), the electrical conductivity tends to stable after 900 s. A strong linear relationship was found between electrical conductivity loss at stabilized time and the strength activity index at 90 days, with a coefficient of determination (R2) of 0.93. Additionally, grinding and calcining treatments can significantly enhance the pozzolanic activity of iron tailing powders. Therefore, the new proposed method was a simple and efficient technique for characterizing the pozzolanic activity of iron tailing powders, and provided a solid foundation for the utilization of iron tailings.
How to cite: Zhan, S. and Deng, Y.: A simple and efficient method for characterizing the pozzolanic activity of iron tailing powders using electrical conductivity, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-1497, https://doi.org/10.5194/egusphere-egu26-1497, 2026.
Coal and lignite mining have produced enormous amounts of mine waste usually collected and left in long term storage facilities such (tailings, waste-rock dumps, and mine-water treatment) across Europe. These deposits may cause long-term environmental and geotechnical risks (instability, acid mine drainage, vegetation and land degradation), while coexisting with opportunities for the recovery of critical raw materials (CRMs). Improving the characterization of these volumes and integrating multiple data inputs is essential to support circular economy approaches to rethink the way mine waste is managed and contribute to regional transition processes in coal regions.
In practice, understanding and giving value to waste facilities is hindered by fragmented information across satellite products (multi and hyper-spectral, thermal, radar interferometry), airborne or UAV digital maps (laser scans, hyper-clouds, geophysical surveys), in-situ sensors, geotechnical observations, geochemical and mineralogical data. As a result, sites cannot be easily compared and Earth-observation data are rarely used directly to support resource assessments and decisions.
In this contribution, we demonstrate the concept of a European data-space framework dedicated to coal waste facilities. CRMsDataSpace intends to collect scattered data from different sources and formats in a shared digital framework, where the data can be used together and facilitate interpretation. The data is subjected to quality control respecting data ownership and access control. This framework connects Earth observation (EO) data with ground-based references and laboratory analyses at different temporal and spatial scales by using common data structures, shared terminology, and modelling workflows that turn observations into indicators useful for CRM assessment and decision-making.
Demonstration waste facilities in coal and post-mining regions of Germany, Spain, Poland, and Romania will be used as case scenarios. The project combines existing legacy, compositional and EO products with new mineralogical and geochemical analyses, hydrometallurgical recovery tests and exploration drilling to provide comprehensive characterization. This infrastructure is implemented in a Minimum Viable Data Space, allowing sites to be compared in a consistent way and helping to identify and prioritize reprocessing opportunities. While the initial focus is on coal waste streams, the CRMsDataSpace tool is intended to be transferable to other mine-waste origins, supporting circular economy strategies and business opportunity for mining operators or governmental agencies aligned with the European Green Deal and the Critical Raw Materials Act.
The presented digital framework is developed within the EU-CRMsDataSpace project funded by the Research Fund for Coal and Steel (RFCS).
How to cite: Flores, H., Dogan, T., Krzemień, A., Marquez, A., and Riesgo, P.: CRMsDataSpace: Building a European Data Space for Critical Raw Materials, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-19984, https://doi.org/10.5194/egusphere-egu26-19984, 2026.
Mining generates more than 14 billion tonnes of waste each year, which must be safely stored and managed over decades. In circular-economy frameworks, mine waste is increasingly recognised not only as an environmental liability but also as a potential secondary resource, and industrial-scale valorisation initiatives are already being implemented by major mining companies and specialised start-ups. Using mining waste for CO2 sequestration presents a particularly promising valorisation approach, as it promotes both the “zero waste” as well as the “net zero CO2” principles.
In this contribution, we explore integrated Earth-observation (EO) workflows to support the assessment of CO2 sequestration potential at mine waste sites through two complementary pathways: (i) passive mineral carbonation, where atmospheric CO2 is bound through natural weathering of reactive waste materials, and (ii) carbon sequestration through revegetation and improved stewardship of post-mining landscapes.
Mafic and ultramafic waste materials rich in Mg-Fe-Ca-bearing silicates, including olivine, serpentine, pyroxenes, amphiboles and smectites, exhibit high carbonation potential and occur widely in waste derived from mining of e.g. asbestos, diamonds, Ni-Cr, PGM, and Pb-Zn ores. Despite their abundance in active and legacy waste facilities, identifying and quantifying these minerals at scale remains challenging, as mine waste is intrinsically heterogeneous and existing mine-waste inventories rarely include spatially explicit mineralogical information. Using resolution-enhanced satellite hyperspectral data, we derive spatially continuous maps of reactive mineral assemblages in mine waste deposits through band-ratio analysis, minimum-wavelength mapping, and spectral unmixing based on dedicated mineral libraries. These products support the screening, targeting, and design of mineral-based CO₂ sequestration strategies such as enhanced weathering or ex-situ carbonation.
In parallel, we monitor revegetation dynamics on mine waste deposits as a proxy for vegetation-based carbon sequestration. Reclamation commonly involves the addition of topsoil or the construction of technosols from waste materials to enable plant growth and soil development. However, revegetation success is often spatially variable due to hydrology, nutrient limitations, toxicity, and surface instability. We apply decomposition and trend analysis to long-term Sentinel-2 and Landsat vegetation-index time series to quantify revegetation trajectories across multiple closed mine sites. This approach reveals fine-scale patterns in rehabilitation success, identifies erosion-affected or delayed-recovery zones and provides objective indicators for optimising reclamation strategies. Where available, LiDAR and hyperspectral data are integrated to characterise vertical vegetation structure and species composition, providing a basis for above-ground biomass estimation, for carbon accounting and crediting assessments.
The presented EO-based monitoring framework, developed within the EU-funded MOSMIN project, enables consistent comparison, prioritisation, and tracking of CO2 sequestration potential across heterogeneous waste deposits, supporting more sustainable land-use and waste-management strategies.
How to cite: Kirsch, M., Lorenz, S., Thiele, S., Nwazelibe, V., Chakraborty, R., and Gloaguen, R.: Earth-observation for CO2 sequestration at mine waste sites, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-9747, https://doi.org/10.5194/egusphere-egu26-9747, 2026.
The legacy of abandoned mining sites poses a major threat to both the environment and human health due to the possible accumulation of potentially toxic elements in soils and sediments. The São Domingos mining area, located in the Iberian Pyrite Belt, represents one such site, where mining activities ceased without the implementation of environmental control or remediation measures. As a consequence, high concentrations of potentially toxic elements have accumulated throughout the surrounding area, leading to severe environmental degradation.
In this context, to improve the understanding of ecological and human health risks in this area, sediment samples were collected from four drills carried out at spaced locations along approximately 5 km of the former mining area. The samples were separated into two grain-size fractions (<2 mm and <2 µm), the latter being particularly relevant due to its enhanced capacity to retain contaminants. Geochemical analyses were performed, and contamination levels were evaluated using several ecological risk indices, including the contamination factor, the geoaccumulation index, and the potential ecological risk index. Human health risks were assessed using the hazard quotient and cancer risk approaches, considering multiple exposure pathways, namely ingestion, inhalation, and dermal contact, for both adults and children.
The results show that potentially toxic element concentrations in most drills largely exceed background values, particularly in the <2 µm fraction. Very high ecological risk levels were identified, well above established thresholds, and the geoaccumulation index classifies several elements as extremely polluted. Human health risk assessment reveals significant non-carcinogenic and carcinogenic risks, with children identified as the most vulnerable population group. Hg, Pb, and As were the elements that contributed most significantly to the observed ecological and human health risks. The most hazardous drills are located close to former ore extraction and processing areas, with a progressive decrease in both environmental and human health risks observed with increasing distance from these zones. These findings are particularly important due to frequent tourist visits throughout the year and the presence of nearby communities, highlighting the potential for widespread human exposure.
Overall, this study demonstrates that the São Domingos mining area represents a serious ecological and public health concern, highlighting the urgent need for remediation measures and continuous environmental monitoring.
How to cite: Gomes, P. and Valente, T.: Ecological and human health risk assessment of sediments from the São Domingos old mining área, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-22613, https://doi.org/10.5194/egusphere-egu26-22613, 2026.
Water pollution by potentially toxic elements has become a growing global concern, particularly in developing countries, where rapid industrialization and mining activities often outpace environmental regulation. In Brazil, mining stands out as one of the main contributors to surface water contamination, especially in historically exploited regions such as the Iron Quadrangle. This study presents a comprehensive assessment of surface water quality in the Iron Quadrangle, one of Brazil's most important mining regions, with a focus on contamination by potentially toxic elements. A total of 487 water samples were collected from third-order drainage basins across an area of 7,000 km², resulting in a high sampling density (one point per 14.4 km²). Samples were analyzed for major, minor, and trace elements and compared with national and international water quality guidelines. Pollution levels were evaluated using the Heavy Metal Pollution Index (HPI) and the Heavy Metal Evaluation Index (HEI), complemented by high-resolution geochemical mapping. The results revealed elevated concentrations of As, Cd, Pb, Cr, and Zn, with numerous samples exceeding drinking-water standards. The highest concentrations were observed in the Doce, das Velhas, and Paraopeba river basins, particularly within the municipalities of Nova Lima, Mariana, Ouro Preto, and Brumadinho. HPI values ranged from 0.9 to 2871, with 34% of the samples classified as highly polluted. Arsenic, Pb, and Cd were the dominant contributors to HPI, with mean values of 36.8, 35.4, and 26.8, respectively, far exceeding those of other elements (0.001–2.83). Pb and As alone exceeded the pollution threshold (HPI > 100) in 14.3% and 14.1% of the sampling points, respectively.
HEI values ranged from 3.2 to 70.6, with a mean of 8.65. Overall, 22% of samples were classified as moderately polluted and 6.8% as polluted. As, Pb, and Cd again dominated HEI contributions, with average values of 2.95, 2.61, and 1.25, markedly higher than those of other elements (0.016–0.87). The comparison of the indices indicates that HPI exhibits greater variability due to its element-specific weighting, whereas HEI shows a more stable, uniform behavior. The spatial distribution of the indices highlighted severely polluted areas associated with intense mining activity, unplanned urbanization, and natural geogenic sources. The spatial patterns of both indices delineate severely contaminated zones linked to intensive mining, unplanned urbanization, and geogenic inputs. The integrated methodology proved effective in identifying critical contamination hotspots near urban areas, rural communities, and water supply intakes, offering a robust scientific basis for environmental management, monitoring programs, and public policy development in highly impacted regions.
How to cite: Valente, T., Vicq, R., Leite, M. G. P., Leão, L. P., Nalini Júnior, H. A., Gomes, P., and Fonseca, R.: Assessing Mine-Related Surface Water Contamination in the Iron Quadrangle (Brazil): A Risk-Based Spatial Analysis Using Potentially Toxic Elements Indices, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-22557, https://doi.org/10.5194/egusphere-egu26-22557, 2026.
Atmospheric aerosols are a key component of the Earth system, originating from both natural processes and human activities. Mining is a major industrial source of airborne particulate matter, particularly in open-pit operations where blasting, crushing, hauling, and waste management continuously generate dust. Mine waste facilities, such as tailings storage facilities (TSFs) and waste-rock dumps, are among the dominant anthropogenic sources of mineral dust emissions in many mining districts, due to their large exposed surface areas and limited vegetation cover. Mining aerosols typically consist of mineral particles such as silica and metal oxides, often enriched in toxic trace elements, making them relevant from both public health and environmental perspectives. While coarse particles (PM10) tend to deposit near the source, fine particles (PM2.5 and smaller) can remain suspended and be transported over tens of kilometres, contributing to regional air quality degradation and population exposure.
Monitoring strategies at mining sites primarily rely on in-situ instruments, which provide accurate point measurements but limited spatial context. These observations often do not capture the full extent of dust dispersion or identify preferential transport pathways toward populated areas, particularly in remote or topographically complex regions. Satellite-based aerosol observations offer a valuable complement by providing spatially continuous, long-term, and independent information on aerosol presence, intensity, and transport, yet their application to mining environments remains underexplored.
The MOSMIN project addresses this gap by developing a multi-sensor satellite-based framework to characterise mining-related aerosols across contrasting climatic and surface environments. Satellite products from MODIS MAIAC aerosol optical depth (AOD), Sentinel-5P aerosol index (AI), and CALIOP lidar profiles are combined with meteorological reanalysis to investigate dust emissions, transport, and vertical structure at four pilot sites: Roșia Poieni (Romania), Talabre (Chile), Trident (Zambia), and Aitik (Sweden). Sentinel-5P AI identifies absorbing aerosol hotspots, while MODIS AOD resolves local dust plumes over open pits and TSFs. CALIOP vertical profiles provide complementary information on plume height and vertical structure, improving the interpretation of satellite column measurements.
The combined satellite analysis reveals pronounced site-specific differences driven by meteorology and surface properties. The hyper-arid Talabre site exhibits persistent absorbing aerosol signals and extended plume dispersion, while the Trident mining complex shows strong seasonal contrasts, with enhanced aerosol loading during the dry season and additional contributions from regional biomass burning. At Roșia Poieni, dust emissions show a clear summer maximum linked to increased mechanical activity and boundary-layer mixing, with aerosol accumulation frequently occurring in surrounding valleys rather than directly above the open pit. At the high-latitude Aitik site, mining-related aerosol signals are primarily detectable during the snow-free summer period, when reduced surface brightness allows reliable satellite retrievals of dust transport from exposed mining surfaces.
Overall, the results demonstrate that satellite observations provide essential spatial, temporal, and vertical context for assessing mining-related aerosols, extending monitoring beyond the mine fence and supporting exposure assessment, environmental management, and mitigation planning. In addition, satellite-derived products offer a consistent and accessible basis for communicating dust impact to regulators and other stakeholders, complementing in-situ measurements.
How to cite: Deaconu, L.-T., Kerekes, A.-H., Baciu, L.-C., and Kirsch, M.: Combining MODIS, Sentinel-5P, and CALIOP to monitor dust emissions from mining activities, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-6316, https://doi.org/10.5194/egusphere-egu26-6316, 2026.
Industrial mining activities have long driven the growth of civilization over the past hundred years. The large-scale mining activities, however, result in large amounts of residual waste in forms of e.g., rock waste and tailings. Engineered embankments or dams are typically used to contain these residual wastes, ensuring their long-term containment and stability. However, these dams can pose a risk of failure, and uncontrolled release of contained materials can bring harm to the environment and nearby communities. The EU-funded project, MOSMIN (Multiscale observation services for mining related deposits), aims to integrate Earth observation techniques and in-situ geophysical survey for geotechnical and environmental monitoring, as well as the valorisation of mining-related waste. Within this framework, we explore the potential of passive seismic methods as a non-invasive approach for imaging and monitoring such mining waste deposits without the need for high impact seismic sources such as dynamite and vibroseis.
In this work, we present the first results of multidimensional imaging of a legacy Tailings Storage Facility (TSF) using a large-N passive seismic experiment to assess the geotechnical integrity of the legacy TSF, and its potential volume for valorisation. We deployed a total 200 autonomous seismic stations, consisting of 160 1-component and 40 3-components sensors on the surface of a TSF in a closed mining site in Laisvall, Sweden. The seismic stations were deployed as a grid array, with interstation distance of 20 m that covers the whole 500 x 700 m area of the TSF.
We applied the Horizontal-to-Vertical Spectral Ratio method to the 3-components seismic sensors to extract the Rayleigh wave ellipticity curves. The curves obtained were utilized to model the one-dimensional shear wave velocity (Vs) for every station. These values were subsequently interpolated to create a pseudo three-dimensional Vs model of the TSF. Additionally, we also applied Ambient Noise Tomography (ANT) to fully utilize the full coverage of the deployed large-N array. Preliminary results of this research show a robust Vs model that reveals the internal subsurface structure of the deposited tailings, highlighting areas with thicker deposits and lower Vs value. Ultimately, we discuss our results with respect to the implications for storage facilities safety and re-valorisation of the legacy deposits.
How to cite: Trichandi, R., Haberland, C., Ryberg, T., Rodríguez Tribaldos, V., Kirsch, M., and Krawczyk, C.: Multidimensional Passive Seismic Imaging of Legacy Tailings Storage Facility , EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-9823, https://doi.org/10.5194/egusphere-egu26-9823, 2026.
Tailings and waste rocks are residuals of industrial mining operations and their collection amounts to the world's largest human-made structures both in spatial extent and mass. The catastrophic consequences of tailings dam failures have been extensively documented, prompting the establishment of stringent regulatory frameworks to mitigate environmental and societal risks. The United Nations Environment Programme (UNEP) introduced the Global Industry Standard on Tailings Management (GISTM) in 2020, which mandates the implementation of monitoring concepts that manage risks throughout the lifecycle of a tailings facility. Addressing this requirement is a key goal of MOSMIN (Multiscale observation services for mining-related deposits), an EU-funded initiative aimed at establishing comprehensive monitoring solutions for mining-related deposits. The project integrates Earth observation technologies with ground-based geophysical measurements to create unified datasets. These datasets are then analysed using advanced computational techniques, including machine learning algorithms, to characterise spatio-temporal dynamics relevant to the safety and sustainability of mining-related deposits.
We contribute to these efforts with in situ high-resolution passive seismic measurements conducted at the tailings storage facilities of two copper mines: the FQM Sentinel mine in Kalumbila, Zambia, and the CODELCO Chuquicamata mine near Calama, Chile. Both experiments aim to seismically characterize the internal structure of the dams and to monitor subsurface processes at different scales, resolutions and depths of investigation through the creation of shear wave velocity models using ambient noise tomography (ANT). Similar array designs were implemented for both sites. Each site was equipped with a kilometers-long, trenched fiber-optic cable interrogated by a commercial Distributed Acoustic Sensing (DAS) system along with 30 conventional geophones. Both types of instrumentation were installed parallel to targeted tailings dam sectors and recorded during regular mining, disposal, and maintenance activities around the tailings facility for several months. However, the highly variable seismic wavefield generated by the active mining environment poses challenges for the ANT procedure. In order to obtain an overview of the wavefield’s spatio-temporal behaviour, we calculate the strain-rate root-mean-square (RMS) in different frequency bands across the entire recording period and fiber array, which encompasses approximately two months across 4 km and 9 months across 1.5 km of optic fiber for the Chile and Zambia sites, respectively. We present results regarding the spatio-temporal variation and stability of cross-correlations, and discuss the feasibility of performing Multi-channel Analysis of Surface Waves (MASW) to obtain high-resolution profiles of the velocity structure of the dam across space and time.
Ultimately, tracking seismic changes in the dam structure could be used as an additional tool for non-invasive, spatially and temporally continuous geotechnical monitoring of the tailings storage facility and, in joint analysis with InSAR-derived surface deformation, reduce false alarms and enable physically meaningful, surface-subsurface interpretation.
How to cite: Wollin, C., Rodríguez Tribaldos, V., Haberland, C., Ryberg, T., Trichandi, R., Krawczyk, C., and Kirsch, M.: Fiber-optic monitoring of tailings dams in the MOSMIN project, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-18342, https://doi.org/10.5194/egusphere-egu26-18342, 2026.
Shield tunneling generates a large volume of shield tunnel spoil (STS). Conventional disposal practices are associated with high costs, low resource recovery efficiency, and considerable environmental burdens. Meanwhile, synchronous backfill grouting materials used during shield advancement are critical for controlling ground settlement and maintaining lining stability. To address these issues, this study proposes an Alkali-Activated Full-Component Shield Tunnel Spoil Regenerated Solid-Waste Grouting Material (AFS-RSWGM). The material is formulated through the synergistic utilization of cement, fly ash, shield-sieved sand, and spoil soil, and incorporates alkali activation together with the pozzolanic effect of fly ash to enable full-component resource utilization of STS. This approach aims to reduce spoil handling costs, improve recycling efficiency, and enhance the performance of grouting materials. Key findings include:
(1) Based on cement, fly ash, shield-sieved sand, and shield tunnel spoil soil, and coupled with NaOH solution alkali activation and the fly ash pozzolanic effect, AFS-RSWGM was developed. Response Surface Methodology (RSM) was employed to optimize three key factors, namely the water–binder ratio (A), binder–sand ratio (B), and shield tunnel spoil soil (STSS)–water ratio (C). The construction adaptability and mechanical performance were evaluated using macroscopic indices such as compressive strength, fluidity, and bleeding rate. The results indicate that, after mix optimization, the 28-day compressive strength increased by approximately 32% compared with traditional cement-based grouting materials (TCGM), while fluidity increased and bleeding decreased, demonstrating superior overall adaptability and mechanical performance.
(2) The micro-mechanism underlying the performance enhancement of the optimized mix was investigated through multi-scale characterization, including rheological tests, hydration heat analysis, and SEM/XRD/FTIR. The results show that the optimized slurry exhibits a reduced yield stress and pronounced shear-thinning behavior. The hydration heat evolution displays a bimodal exothermic profile, with a significantly intensified second exothermic peak. Microstructural analyses reveal that alkali activation promotes the dissolution of aluminosilicate components in the spoil, producing abundant amorphous C-A-S-H gel and AFt. In addition, fly ash continuously supplies reactive SiO2 and Al2O3, refining the interfacial transition zone (ITZ) and reducing porosity. Accordingly, a coherent evidence chain of "performance enhancement–structural evolution–reaction mechanism" is established.
(3) In the Jinan Metro Line 4 project, the left and right lines adopted TCGM and AFS-RSWGM, respectively, for synchronous grouting. A comparative analysis of settlement monitoring data verified the engineering effectiveness of the proposed material. The results demonstrate that AFS-RSWGM limited the maximum surface settlement to approximately 12.1 mm, representing a 68.6% reduction relative to conventional slurry, and achieved settlement stabilization 65 days earlier. Moreover, no issues such as segment dislocation, cracking, or grout leakage were observed during right-line construction, indicating a marked improvement in lining integrity. Based on the above engineering verification outcomes, construction risk identification and control were carried out, highlighting the transition from material optimization to intelligent construction management and control.
How to cite: Zhou, Y., Yang, Z., and Gao, Y.: Development and Engineering Application Validation of Alkali-Activated Full-Component Shield Tunnel Spoil Regenerated Solid-Waste Grouting Material, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-4393, https://doi.org/10.5194/egusphere-egu26-4393, 2026.
