We live in a time with a growing global demand for critical raw materials, as well as increasing environmental and geopolitical concerns. This context has intensified the need for more sustainable resource strategies. Among these, the secondary recovery of industrial by-products has gained traction. It is seen as a promising alternative to traditional mining. Despite their known residual metal content and reactive silicate matrix, ferro-nickel slags (FNS), generated during nickel smelting, represent a largely underexplored secondary resource. This Master’s thesis addresses this gap, by investigating the secondary recovery and repurposing potential of FNS. Case studies are performed with slags originating from two sites: Cerro Matoso (Colombia) and Loma de Níquel (Venezuela). The study aims to assess whether these industrial byproducts can be used as alternative resources within a circular economy framework. This can either be by recovering residual metallic elements or by repurposing the bulk slag material. The research is based on a multi-method approach combining field sampling, chemical analysis (pXRF and ICP-OES), and mineralogical and reflectance assessment (XRD, ASD). The compositions of the slags were examined with a focus on their residual nickel content and its hosting mineral phases. Their suitability was tested for repurposing as cement alternatives, fertilizers, carbon mineralization, mineral wool and asphalt. Success criteria were set up, and evaluated based on physical, chemical, and economic feasibility. Results showed that both Cerro Matoso’s and Loma de Níquel’s slags contain valuable metals (e.g.
Ni, Co, Fe) and exhibit favorable characteristics for multiple re-use pathways. However, feasibility is largely influenced by mineralogical entrapment, as well as economical and regulatory constraints. This study explores the untapped value of FNS and emphasizes the importance of further investigating secondary recovery strategies. It contributes to the broader discourse on sustainable resource management by demonstrating how industrial waste can transition from liability to asset when viewed through a circular economy lens.

The Iberian Pyrite Belt (IPB), a historically mined Volcanogenic Massive Sulfide (VMS) region in southern Spain and Portugal, suffers from severe environmental degradation due to unregulated mine closures. This thesis develops a scalable rehabilitation strategy for legacy mine waste in the IPB, using data and samples obtained from the inactive San Miguel mine site. The findings are expanded into broader recommendations for an arbitrarily chosen study area, addressing both active and inactive sites, and offering guidance for sustainable mine management in the IPB and similar mining regions worldwide. In doing so, a multidisciplinary methodology is applied, integrating geochemical analysis, ArcGIS-based spatial modelling, literature reviews, cost assessments, and a Social Life Cycle Assessment (S-LCA) to ensure a comprehensive evaluation of rehabilitation potential and impact in the study area. Heavy metal contamination, primarily arsenic (As), copper (Cu), and lead (Pb), was identified as a major concern, with all sampled materials from San Miguel exceeding regulatory thresholds. The pollution in this area is mainly linked to acid mine drainage (AMD) and mobilization of heavy metals from historic mine waste and slag deposit. Geo-spatial extrapolation using Sentinel-2 imagery enabled mapping of contamination across the study area, justifying areawide remediation measures. A multifaceted rehabilitation strategy is proposed for the study area, combining physical and biological treatments to address AMD and heavy metal pollution from the inactive mine sites. The proposed interventions include the installation of geo-membranes in historical mine ponds to prevent leachate migration,while Sulfate Reducing Bacteria (SRB), applied via Diffusion Active Reactive Permeable Barriers (DAPRB) systems, will treat AMD by neutralizing acidity and precipitating insoluble sulfide metal compounds. Phytostabilization, using metal tolerant native plants, will immobilize contaminants in soil, and revegetation will enhance slope stability and support ecosystem recovery. Together, these approaches address historical and present mining related pollution in the study without aiming to eliminate naturally occurring acid rock drainage (ARD), focusing instead on mitigating its mining induced intensification. The total estimated rehabilitation cost for the seven historical mine sites in the study area is approximately €25.2 million, with revegetation and geo-membrane installation being the most expensive components. A S-LCA was conducted to evaluate the socal and socio-economic impacts of legacy and ongoing mining activities, as well as the projected outcomes of the proposed rehabilitation efforts in the study area. The S-LCA shows that historical and active mining have disproportionately affected local residents, farmers, and municipalities in terms of health and environmental degradation.For instance, the study area is commonly referred to as the triangle of death, whereas it has the largest cancer mortality rate in all of Spain. Conversely, reclamation improves outcomes in those same domains, especially for communities closest to the intervention zone of the study area. Recommendations are also formulated for Zones 2–4, which include active and inactive mine sites. Inactive mines should adopt the study area plan with minimal adaptation. Active mines must incorporate early-phase AMD mitigation, proactive monitoring, and closure planning to prevent legacy pollution.

With demand for lithium predicted to continue increasing in the coming years, lithium exploration and the development of recovery techniques to extract it will become increasingly important. Lithium is particularly important for the energy transition due to its use in lithium-ion batteries. A major source of lithium are Lithium-Caesium-Tantalum (LCT) pegmatites. Lithium is contained within spodumene crystals and these are therefore the focus of most extraction techniques. The main objective of this study was to create an overview of the lithium distribution in lithium pegmatites based on textural and mineralogical information, combined with elemental analysis using Laser Induced Breakdown Spectroscopy (LIBS). The purpose was to improve the understanding of spodumene characteristics in lithium pegmatites which could affect lithium exploration and recovery.
Six samples from two different lithium pegmatite fields were analysed. Four samples were from the Bergby pegmatite field in Sweden and two samples were from the Bougouni pegmatite field in Mali. Petrographic descriptions were made to understand the mineralogy and textures of spodumene and LIBS analysis was used to measure lithium concentrations across profiles on a micrometre scale. Notable features in the Bergby (Sweden) samples included recrystallised, fine grained spodumene in uneven rims around the primary spodumene crystals as well as in the finer grained groundmass. The average lithium content measured for spodumene from the block samples was between 1.4 to 2.1 wt % Li, which is lower than the commonly measured range for spodumene of 2.8 to 3.5 wt % Li (Aylmore et al., 2018). LIBS analysis on the thin sections was attempted and showed higher average lithium content in the micrometre-scale fractures in the spodumene than in the surrounding spodumene crystal. The results of this thesis show that the majority of the lithium remains contained within primary spodumene crystals in lithium pegmatites but lower concentrations are also present in certain locations in the surrounding rock. Additionally, it indicates that the Keyence EA-300 may not be suitable for Li detection in spodumene crystals due to the significant differences in lithium concentration between thin section and block sample measurements. In future it would be critical to consider factors such as matrix effects, sample preparation and calibration of the Keyence EA-300 for true quantitative analysis of lithium content in spodumene.

This multidisciplinary report explores the transition potential of the Phalaborwa region, South Africa, from a mining-focused economy to one that integrates sustainable water, energy, and food (WEF) systems in a post extractive setting. Set within a semi-arid climate with significant resource challenges, the study assesses WEF capacities to propose strategic, sustainable development solutions. Analysing critical issues like water scarcity, renewable energy potential, and soil management, the study presents frameworks for sustainable agriculture, water management, and energy solutions to support post-mining economic resilience. Through a multidisciplinary methodology that integrates engineering assessments and urban planning, the report addresses critical biophysical resource issues. The findings emphasize the region’s unique resource inter dependencies, outlining frameworks for post-mining development that strengthen resilience to climate pressures and resource limitations. Ultimately, this study provides actionable insights for creating a balanced, sustain able future for Phalaborwa and the surrounding area. Although the study proposes frameworks that could inform similar transitions in other semi-arid, resource-constrained regions, it also emphasizes the importance of addressing the unique complexities of each area to ensure that solutions are appropriately tailored.