This thesis investigates the sustainable processing of Kukersite waste rock, a by-product of Estonia’s oil shale industry, through the development of a flotation-based flowsheet. The material, composed mainly of calcite, dolomite, kerogen, and silica, was processed using a combination of sensor-based sorting, controlled milling, and flotation. A staged methodology was applied: laboratory-scale mechanical flotation was used to establish effective reagent regimes, while laboratory-scale pneumatic flotation with Maelgwyn’s IMHOFLOT unit was conducted to study hydrodynamic effects and optimize operating conditions. Froth monitoring supported by Gaussian-mixture-model clustering provided additional insight into flotation dynamics and indicated opportunities for real-time process control. Pilot-scale pneumatic flotation trials then validated the combined reagent–hydrodynamic methodology, achieving kerogen concentrates of 42\% grade at 55\% recovery in the rougher stage and 29.5\% grade at 80.4\% recovery after scavengers, as well as calcite concentrates of 84\% CaCO$_3$ at 70\% recovery in the rougher stage and 96\% CaCO$_3$ at 40\% overall recovery after two cleaning stages and regrinding. The resulting flowsheet integrates rougher, scavenger, and cleaning stages with regrinding, producing industrially relevant concentrates and valorizing carbonate-rich tailings. Overall, this study provides the first proof of concept for Kukersite flotation, demonstrating that pneumatic flotation can deliver resource efficiency, high product quality, and reduced environmental impact within a circular economy framework.

The global transition to green energy has intensified demand for critical raw materials, increasing interest in deep-sea mineral resources such as cobalt-rich ferromanganese (Fe-Mn) crusts on seamounts like Tropic Seamount in the NE Atlantic. This thesis investigates the relationship between water depth and Fe-Mn crust composition and evaluates whether incorporating this relationship through Co-kriging (CK) improves resource estimation compared to Ordinary Kriging (OK). Geochemical and bathymetric data were analyzed using exploratory data analysis. The estimation workflow included block model generation, isometric log-ratio (ILR) transformation, Landmark-ISOMAP embedding for locally varying anisotropy, variogram modeling, and geostatistical estimation with Ordinary Kriging, Simple Co-Kriging (SCK) and Intrinsic Collocated Co-Kriging (ICCK) as well as Inverse Distance Weighted (IDW) Estimation. Model performance was assessed using Quantitative Kriging Neighborhood Analysis (QKNA) metrics and leave-one-out cross-validation (LOOCV), with a critical evaluation of LOOCV’s limitations.

Results demonstrate a significant relationship between water depth and Fe-Mn crust composition, with a significant improvement in estimation accuracy and confidence when water depth is used as the secondary variable in Co-Kriging, with SCK and ICCK providing more accurate and confident resource estimates than OK. ICCK also performed better than IDW. For the first time, tonnage calculations for metals in Fe-Mn crusts based on a 3D block model and real geochemical data are presented, highlighting Tropic Seamount’s potential as a substantial mineral resource for Europe. The workflow developed in this study, including ILR transformation and L-ISOMAP embedding, proved effective for handling compositional data and spatial anisotropy. The study also identifies methodological limitations, such as the need for improved variography, better sampling distribution, consideration of non-metallic elements, and more advanced cross-validation techniques. The assumption that the top 1 cm of crust represents the entire deposit is noted as a simplification, and future research should address vertical stratigraphy and sampling distribution.

The findings indicate that integrating ILR transformation and Landmark-ISOMAP embedding with Co-Kriging leads to better resource estimation for Fe-Mn crusts, enabling more confident and accurate assessments. This methodology offers significant potential for mineral resource exploration and future research in both marine and terrestrial environments.

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.

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.

The implementation of autonomous haulage systems in open-pit mines is a progressive step in the industry, but it brings potential safety risks that need careful evaluation. This study developed a discrete event simulation model to analyze and evaluate these risks in different operating scenarios -fully autonomous, hybrid (a mix of autonomous and human-operated vehicles), and non-autonomous operations.The simulation model was developed using the HAULSIM and Anylogic software, integrated mine layout, haulage operations, and various fleet compositions. It provided insights into collision risks, a significant concern in mining safety literature. Results showed that collisions were inversely proportional to the number of autonomous vehicles in operation, indicating the potential safety advantages of fully autonomous operations. However, certain high-traffic intersections were identified as high-risk areas, emphasizing the need for targeted risk mitigation strategies. Further, a profile risk matrix was developed to provide a comprehensive view of collision severity and likelihood in each scenario. This highlighted the impact of collisions on both human safety and project operations. Based on the results, risk mitigation strategies were proposed, with a focus on redesigning intersections, implementing strict rules for human-operated trucks in autonomous zones, and improving autonomous vehicle capabilities. The study, while insightful, was limited by assumptions and the generic nature of operational data used in the simulation. Therefore, future research should seek to incorporate more detailed, mine-specific data and empirical insights from projects that have implemented autonomous haulage systems. Continuous advancements in autonomous technology and simulation modeling will be key to ensuring a safe and productive mining environment.

Frisia Zout B.V. extracts salt from the subsurface by means of solution mining in the north-western part of The Netherlands. The caverns are situated in the Zechstein-II Halite at a depth of around 2.5 km. Because of this depth and the low operating pressure (around 60% of lithostatic pressure) the salt creep within the cavern is high. Once a cavern is at the end of its lifetime it is decommissioned and shut in. During the shut-in period the cavern blanket fluid is removed and replaced with brine and gets time to equalize in pressure and temperature with its surroundings before being permanently abandoned. At the time of abandonment there is still a small pressure deficit (cavern brine at 98% of lithostatic pressure at roof of cavern). At this pressure deficit there is, in theory, still some salt creep because of the difference in pressure between the cavern brine and surrounding salt walls induced by lithostatic pressure. Since the cavern is closed and still creeps, the brine will escape by means of permeation through the surrounding salt walls and roof. At this point an equilibrium is reached between the cavern convergence and the brine permeation around the cavern.
This research aims to get a better understanding of the cavern convergence and permeation processes after abandonment. For this, a cavern convergence- and brine permeation model is made. Next to this the potential surface subsidence due to the migration of brine to more permeable layers is investigated. In the convergence model, the cavern is modelled as a stack of cylinders and a Norton-Hoff power law squeeze model is applied to the cavern. The squeeze model consists of 2 parts, a linear and a nonlinear part. The nonlinear part is most significant during the production phase and in these high-pressure deficits the squeeze model is fitted on the available production data. Recent creep tests on salt samples under lower pressure deficits (Bérest et al., 2019) have confirmed that the linear part becomes the most significant in the low-pressure deficit region and have shown that the linear creep is smaller than the linear component of existing squeeze model used for production.
Next to this a sensitivity analysis was done on the convergence model by varying the input variables of the model. The parameters that have a large uncertainty and have a large impact on the model were the linear part of the squeeze model and the width of a slice. To give a range of outputs of the convergence model a P10, P50 and P90 scenario is created where these are percentiles from the input range of the sensitivity analysis. The outcome of the convergence model at a cavern size of 1Mm3 suggests a yearly cavern convergence of around of 5, 103 and 2313 m3/year for the P10, P50 and P90 cases respectively.
Since there is an equilibrium between the cavern convergence and the brine permeation, the output of the convergence model (convergence rate) can be used as an input for the permeation model (permeation rate). For the permeation model, different paraboloid shapes are fitted on each layer and are filled with brine from the converging cavern. Once all the salt layers are filled in, the brine reaches more permeable layers and can freely flow over a larger area. The permeation model is run with the P10, P50 and P90 convergence model scenarios as an input and predicts that the system fills after 26, 588 and 12,363 years respectively. At this point there could be some subsidence because the brine can freely flow over a larger area in the more permeable layers above the Zechstein. This subsidence is 0.016 mm/year for the P50 case after 588 years. A negligible amount compared to unrelated subsidence processes.
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To conclude the cavern convergence rates (even the P10 at 5m3/year) are high compared to the permeability of salt according to the Darcy flow law (around 17 l/year). This could have multiple explanations. From the cavern perspective, the cavern convergence rates could be lower. This could be because of a threshold pressure for salt creep to occur (van Oosterhout et al., 2022) or because of some inaccuracies in the linear component of the squeeze model. Future research could focus on determining the creep rates of salt under low-pressure deficits. From the permeation perspective, other permeation paths next to permeability could be at play as well. In the cavern there could be permeation via anhydrite alterations or via micro fractures created during the production phase of the cavern. It would be good to look at these permeation processes in the future. Next to this the secondary porosity of the salt remains a question as well. A good understanding of this porosity is needed to assess the storage capacity of the overlying salt layers before the brine enters more permeable zones.

The frequent occurrence of catastrophic tailings dam failures underscores the urgent need to improve safety practices and minimise associated risks. This study introduces an advanced tool to evaluate the total Probability of Failure (PoF) of existing tailings dams systematically and effectively, supporting the rational prioritisation of mitigation efforts and minimise risk within the 'As Low As Reasonably Practicable' (ALARP) principle.

The tool utilises a semi-quantitative approach, combining observation frequency and expert judgment. A baseline PoF for each dam construction method and failure category is established using a database of 450 tailings dam incidents and accidents developed in this study. This baseline PoF is subsequently modified based on site-specific factors influencing failure prevalence. A total of 255 key contributing factors are identified based on a fault tree analysis, the Global Industry Standard on Tailings Management (GISTM), and experts in the field. The factors encompass site conditions, design elements, and the level of practise, which address all major credible failure modes and mechanisms. The factors are linked to the failure categories they influence and assigned relative weights through the analytical hierarchy processing method for each dam construction method and failure category. Subsequently, the weights are multiplied by modifiers to account for the effects of site-specific conditions (favourable: 0.2, neutral: 1, adverse: 5, and unknown: 2). Within the tool, users can choose fulfilment conditions for each factor from drop-down menus and the selected inputs are connected to the modifiers. The adjusted weights are multiplied by the baseline PoF of each failure category, given the dam construction method. The summation of these products yields the total PoF of the investigated dam.

The results provide preliminary insight into factors significantly affecting the total PoF for the dam under investigation, aiding in evaluating whether the PoF reduction justifies costs. It facilitates preliminary, rational prioritisation of mitigation measures in accordance with the ALARP principle, contributing to ongoing efforts to improve tailings dam safety.

To validate the tool’s capabilities, two case studies with available data are analysed: the Aznalcóllar failure to examine the ability to identify high-risk factors and a recently improved dam to evaluate if the mitigation efforts are adequately reflected. The studies demonstrate the tool’s potential but also reveal uncertainties, inaccuracies, and limitations. These stem from discrepancies in the baseline PoF, weightings, modifiers, and unaccounted factors. Therefore, caution is warranted in the tool’s utilisation. Recommendations include various improvements and further verification and validation across a broader range of case studies. Value can be added by incorporating additional components and adapting the tool for new dams.

This thesis investigates the impact of truck electrification systems on CO2 emissions and financial aspects in mining. Through comprehensive simulations, the study analyses diesel-electric trucks with trolley assist as well as battery-electric variants with trolley assist and stationary charging. The research findings reveal a noteworthy decline in CO2 emissions and an improvement in cost-effectiveness for the diesel-electric variant with trolley assist. Comparable CO2 savings are observed in battery-electric scenarios, but with varying financial profiles. The transition to battery-electric trucks with trolley assist leads to improved efficiency and associated cost savings. On the other hand, stationary charging entails financial challenges owing to high equipment costs. The analysis of emissions was conducted by different scopes, allowing a differentiated analysis of direct emissions (Scope 1) and indirect emissions (Scopes 2 and 3). This research highlights the significance of adopting a comprehensive approach towards achieving a sustainable future in mining. It provides clear insights into the potential of electrification technologies, particularly highlighted by a 49% CO2 reduction in battery-electric scenarios.

The goal of a mining operation is to extract the maximum value from exploiting the orebody. The equipment used by these mining operations has a nominally rated performance to achieve needed annual production. However, this nominally rated performance is not achieved during operations. This study assesses the underlying causes of reduced shovel production in a mining operation.

The following research questions will be answered in this study: What factors contribute to deviations from the predicted performance? What factors are the most significant? What is the effect of automated trucks on shovel productivity? Can a data-driven model be developed to predict the actual productivity of the shovel in the real world?

The underlying causes of reduced shovel production are assessed through a literature review and five case studies. The case studies consisted of three data analytical desk studies, interviews with industry professionals, and a mine visit to north Africa.

The literature review shows that the mining industry uses formulas to determine the theoretical production rates. The factors in the shovel production formula should be predicted with frequency distributions. Also, truck automation will increase trucking hours, impacting shovel productivity through truck exchange time. The first case study shows a sensitivity analysis of the shovel formula. This sensitivity analysis shows that the swell factor, density, bucket fill, efficiency, and cycle time have a more significant impact than truck exchange time, dumping of the first bucket, and the number of cycles. The second case study shows the underperformance of different electric rope shovel models in different mining operations. The third case study compares the theoretical shovel capacity with the total material moved for 16 years. This shovel capacity and total material ratio should be between 1-2.5 for a mining operation to be classified as above-average-in-class. The fourth case study shows the different factors influencing shovel productivity based on the interviewees' responses. The last case study shows the effects of operational decisions on a mining operation. The literature review and case studies are used to develop a flowchart regarding the factors influencing shovel productivity.

This flowchart was used to synthesise the results. The difference between theoretical and real-world production rates can be decreased when the frequency distributions are known for all the shovel production formula factors. This shovel production formula for annual production rate can be divided into three main pillars. These three pillars are the hourly production rate, use of availability, and mechanical availability. The pillars allow OEMs or mining companies to implement the correct improvement measures to improve shovel productivity. However, one solution for every mining operation will be impossible due to the uncertainty in the data and variability of each mining operation.

To conclude, the factors that contribute to deviations from the predicted performance are categorised as uncontrollable (weather and geographical location), direct (density and cycle time), and indirect (fragmentation and face dimensions), which all impact shovel productivity. The most significant factors are not found during the study, but solving underperformance in the direct factors will solve most of the problems. The effect of automated trucks on shovel productivity will result in additional trucking capacity, which will need to be absorbed by the shovel. Lastly, a data-driven model can be developed with access to all the data from a mining operation. However, this data is often not available to an OEM. Therefore, it is not advisable to develop such a model.

The widespread concerns about climate change, as well as the major enabling factors for the transition that are required to guarantee its control, necessitate research and a tool that can provide insight into the future of copper mining.The world's copper supply is primarily concentrated in a few producing locations: Chile, Peru, Democratic Republic of the Congo, China, and Zambia. More than 50% of the supply of this metal is produced in locations with high water stress. This is a concerning issue as the process to produce copper is particularly water-intensive. Existing physical risks such as landslides, floods, fires, and dangerous amounts of heat stress are also common and so are researched in this thesis.Policy makers, governments, society, banks, and investors are monitoring the impact of climate risks on this industry. Therefore a tool to evaluate the risks on copper mining to allow the stakeholders to assess exposure to climate change has been developed in this thesis. To accurately analyse the future supply of copper, this tool specifically stress tests different standardized NGFS climate scenarios for years 2030 and 2050 for copper mines throughout the globe.The simulation revealed that climate risks are a systematic risk for copper mining companies, with roughly a 50\% of the supply being at high risk. Moreover, the findings suggest that this commodity is rather more vulnerable to transition risks than to physical risks, mainly due to the price of carbon. Furthermore, major producers in Chile and Peru must turn to seawater desalination and this will significantly raise operational costs. In addition, there are concerns over a possible labour migration to regions with food security issues which could jeopardize the skilled mining workforce, more research into this is required. The findings also indicate that countries previously regarded as unattractive locations for investment, such as Zambia and the DRC, may soon rank among the major producing nations with the lowest climatic risk exposure and the lowest industry costs. However, these ratings may be offset by these countries' higher political risks. Climate change will also affect demand. Copper is a key component of the carbon-neutral transition as numerous significant renewable technologies depend on this raw material. Furthermore, conventional copper-intensive applications such as electrical networks will also expand over the next few decades. Although investments have been pledged, it is anticipated that these will fall short of what is required to satisfy the increasing demand. The developed model is static and reflects the issue that mines would face if they kept business as usual. This provides insights on the size of effort required by miners to overcome climate risks as well as to expose how vulnerable this commodity currently is. The model has the potential to be scaled and adapted to other commodities and to other industries. Due to its modular structure assumptions and parameters can be easily updated providing versatility and robustness.

Measuring and analyzing the tunnel deformation through convergence measurements and cross-correlation with geological mapping is essential for understanding and controlling tunnel stability, worker safety and predicting failure zones. In order to achieve this, a new device, the so-called GroundProbe GML is tested and analyzed in this study. Currently, the deformation in the Kristineberg mine is measured through conventional techniques, such as the tape extensometer, that are labor intensive and time-consuming. On top of that, the geological mapping is done by visual inspection by experienced geologists. There is no system in place that correlates the geological setting to the deformation of the tunnels. This research aims to explore the possibility to quantify tunnel wall convergence and correlate the movement to geological circumstances. An accuracy analysis is performed, to identify the accuracy of the Light Detection and Ranging (LiDAR) technology in comparison to conventional techniques. This analysis is conducted in both a controlled (above-ground) and an uncontrolled (underground) environment and focuses on the use of different targets, i.e. prisms or reflectors, and the difference between continuous and periodic measurements. The fresh rock surfaces are also mapped by means of geological LiDAR data as well as Red-Green-Blue (RGB) image analysis and this is correlated with tunnel wall convergence. This is done to increase the understanding of the impact of the geological setting on the tunnel wall convergence.
The accuracy presented by GroundProbe of _3 mm for periodic measurements is difficult to achieve in an underground environment with mining activity. Especially the deformation of measurement points that are at a more oblique angle to the scanner prove to be difficult to assess. The geological LiDAR data can be used to distinguish different rock types and geological features with limited subjectivity. The transition zones from one rock type to the other become clearly visible from the geological LiDAR data. Additionally, geological features such as joints can be identified when combining LiDAR data with RGB image analysis. The primary promotor of tunnel wall convergence is the hanging wall that pushes down on the foot wall in combination with non-uniform waste rock areas, that are for example split into two sections by a joint. In a tunneling environment where mining activities are conducted, such as the application of shotcrete, scaling, blasting and leveling of the floor, periodic measurements with a LiDAR set-up on a tripod are difficult. One of the main limitations is the absence of stable reference points that the LiDAR scanner uses to determine its XYZ-position. The oblique angle can also be a limiting factor, measurement points closer to the LiDAR scanner provide more reliable results. For continuous measurements however, this proves to be less relevant because the repositioning error can be omitted. The LiDAR scanning technology has the potential to be used as geological mapping tool based on the varying reflectivities of different rock types. By combining LiDAR technology with RGB image analysis, a more thorough understanding of the geological setting can be obtained. By relating this understanding to the quantification of the tunnel wall convergence, this technique can be used to correlate the geology to the movement of the rock mass.

Surface mining operations can have a significant visual impact on the surrounding landscape and communities. There have been numerous cases of local populations pushing back against the development of mining operations near their communities. This study aims to determine whether it is possible to assess the visual impact of surface mining operations before the development has started. With this assessment it would become possible to make informed decisions as to pitshell development and selection in terms of visual impact. A tool was developed to determine whether it is possible to make this assessment. This tool must be able to be used to determine the visual impact of two or more scenarios in the pre-feasibility phase of development to assist in the decision of
which scenario will be developed further in the feasibility phase. In this context, the visual impact is defined as the perceived change in the landscape as a result of mine development on local communities around the surface mine development. The scenarios are defined as the option of pitshells designed during the pre-feasibility phase of mine development.

The tool makes a distinction between the physical changes in the landscape caused by the surface mining operation and how this physical change is perceived by anyone viewing the operation.

The tool is GIS based and utilizes the free open-source software QGIS to calculate the physical change in the landscape. The tool calculates the vertical and horizontal visibility angle. The visibility angle describes the extent that the change in the landscape takes up in the view of an observer. In addition
to that, the tool calculates the contrast between the changed colour in the landscape and its surroundings, which describes how much the change stands out. It requires two sets of data to work: a digital elevation model of the prospected surface mine pitshell and the surrounding landscape and a
RGB satellite image of the surrounding area. The DEM provides elevation data for every square metre of the landscape to the GIS, while the satellite image provides RGB colour data. All other data can be generated from the previously mentioned data features.

The tool is tested using a case study, in which several distinct pitshell scenarios are compared against one another on their visual impact. The case study is based on the extension of a limestone quarry in
Belgium, which aims to secure reserve for future operations. The area of interest is surrounded by several small to medium size villages, which would be affected visually by the extension. Therefore, a comparison should be made regarding the visual impact of the several pitshell scenarios. The results showed it is possible to determine the visual impact of surface mining operations before the
development has started. On this basis, it is possible to compare different pitshell scenarios and determine which scenario would be least impactful in terms of visual impact on the local community and surrounding landscape. The reliability of the tool can only be assessed theoretically, however a high level of accuracy is achieved by adhering to guiding principles which are set out in this thesis.

The enlargement of the lock complex of Terneuzen in 2023 will allow Capesize vessels up to 300 meters in length, to access the Ghent-Terneuzen canal and reach the quay of ArcelorMittal Ghent (AMG). The goal of this thesis is to estimate to what extent these vessels can be used, the impact that these vessels will have on the supply chain and the cost impact of the implementation of Capesize vessels. The production of AMG is expected to be increased up to 5.5 million ton of steel for 2026. Therefore, it will require an estimated 12.9 million ton of raw materials (12% increase compared to 2019) which mainly consist of iron ore and coal. Up to 31% of this material can be shipped from source ports that are accessible by Capesize vessels. The draught restriction of 12.5 meters for the canal, limits the amount of bulk material that can be unloaded by the Capesize vessel to 105,000 DWT which is 60% of the maximum of 175,000 DWT. The remaining 70,000 tons of material can be unloaded externally and be transported to AMG by the use of inland barging vessels. The increased volume of Capesize vessels compared to the current Panamax vessels will lead to an increase in load size and a decrease in load frequency which will affect the downstream installations of AMG. Most of the current quay cranes will be unable to unload Capesize vessels due to the increased size of the ships. A proposed crane was introduced in the model to examine the ideal positioning to unload Capesize vessels and barges. 6 realistic scenarios for 2026 have been examined with varying levels of Capesize utilization. As a result of these scenarios vessel arrival lists for full year were simulated. Each of the vessel lists served as input data on a quay model with as results the downstream impact. The main output parameters were the waiting time for sea vessels, waiting time for barges and the amount of material that had to be stored on a temporary storage. In general, the implementation had a negative effect on all three of the output parameters resulting in additional quay costs. The net effect of Capesize vessels on the total costs was positive thanks to the lower shipping price per ton of material. This benefit was partly compensated by the increased costs for barging that was caused by Capesize transport. The shipping costs for Capesize vessels should at least be 2.53 dollar per ton cheaper, to break-even with Panamax vessels. Under current circumstances the full-scale use of Capesize vessels can be feasible. However due the high volatility of the dry bulk market and bunker prices, it is impossible to guarantee this will be the case for 2026.

The lime is a versatile product with multiple applications in everyday life. According to the European lime association, each citizen uses around 150 grams of lime per day. It is used as a base material to produce various products in environmental, agriculture, metallurgical production, construction, and chemical industries, among others. The high range of lime applications generates many limitations based on the content criteria set by the consumers and varies according to the requirement and further use of the lime. According to the European lime association (2017), one of the highest lime uses is on steel production; 40% of the total world production is sold to the steel industry each year. The quality requirements for the lime to be used to produce steel are strict, setting the target for the obtention of lime with a high concentration of CaO and low presence of prejudicial impurities such as phosphorus or sulfur. Calgov lime production plant is located in the south of Spain. It supplies local and national consumers of lime and has been operating for approximately 35 years. The steel manufacturing industry is one of the major clients of the plant consuming about 50% of the total installed capacity. This industry's quality requirements are a significant concern for the plant, and the obtention of limestone with low phosphorus content one of the primary targets for the company's future. Currently, the plant is under high pressure to find and extract limestone with low content of P2O5, below 0.039%, which is the limit set by the client. Seeking to comply with quality and quantity, the plant has performed exploratory work in the southern area of the deposit in which resources of limestone that meet this target are found. In this work, a mine design and scheduling options for the extraction of the south area of Calgov deposit extraction is presented based on the composition requirements set for the limestone. Furthermore, a techno-economic analysis of the extraction scenarios is developed exploring different alternatives to deal with the lack of information about some areas of the deposit and alternatives to ensure a constant feed of lime to the plant, avoid over costs and increase the possible economic return.

To optimise mining in a safe, geotechnically controlled and economical most beneficial way in Mine 2 of the Stjernøy mine, a choice has been made to review the current mining method, sublevel open stoping, and a different mining method, vertical crater retreat. The Stjernøy mine is an open pit and underground mine for Nepheline Syenite and this thesis focuses on Mine 2, the underground mine which is partially completed. The stopes of Mine 2 are closely located to old stopes, which can cause stability issues. Between the new and old stopes is a barrier pillar which is a key element in the stability of the underground mine and the infrastructure for the open pit operation as well. This project consists of field work and laboratory testing to create a basis for the numerical stability analysis of the mine and the creation of a cost model for the two different mining methods. The results of the cost modeling show that the use of sublevel open stoping will result in a cost per tonne of 9.86 NOK and the use of vertical crater retreat will result in a cost per tonne of 10.39 NOK. The use of sublevel open stoping as mining method is the most economically beneficial option for the mining operation. It is less expensive as a mining method and it is a proven method at this mine site. The vertical crater retreat method uses a more expensive blasting method, with the same burden and spacing parameters as the sublevel open stoping. The results of the field work and the laboratory testing provided important parameters for the numerical modelling, such as the strength of the material. Based on these results the numerical modelling also showed that it is beneficial for the stability of the pillar if some stopes near the barrier pillar are not extracted. The extraction of these stopes will decrease the factor of safety of certain areas of the barrier pillar to one or for some areas below one. The stope size has also been reviewed. To make sure that the stopes are well connected to drawpoints, it is important to keep them the same size, which is a stable stope size for the roof. Smaller stope sizes are found to be a bit more stable, however the effect of the increasing amount of pillars is not known on the overall stability.

The current plan of bottom to top bottom sublevel stoping for the Kearney gold vein at the Cavanacaw mine, Omagh, Northern Ireland may not be the most effective in terms of stability. The Kearney ore body is a narrow vein gold deposit, which has been previously exploited through an open pit and is currently being developed as an underground operation using sublevel stoping (modified Avoca mining method). Stability within the mine is one of the key factors to be considered when it comes to hard rock mining. It should be considered equally as important from a safety and economic point of view. The extraction sequence plays an important role when considering the stability of a designed mine. This thesis aims to establish if the current planned sequence of extraction of bottom to top sublevel stoping is the most effective in terms of overall rock stability, or whether an alternative plan would be better? In the context of this thesis, the modified Avoca mining method is a form of sublevel stoping where material is extracted (stoped) between two drives (blind tunnels) and then backfilled.
The project addressed, a conceptual study, field testing and laboratory testing in order to yield the information required to build several numerical models. The numerical modelling was carried out on several different stoping orders which met the constraints set out by Galantas, using the Hoek-Brown model within Plaxis2D. The analysis was conducted on the total displacements, phase displacements, predicted failure points and safety factors. The analysis of the different models showed that an alter- native stoping method of middle to top bottom to middle sublevel stoping peformed better in terms of stability. This improvement in stability was shown by an increase in the minimum safety factor from 3.20 to 3.50, over the current plan. There is further evidence in the reduction of the total number of predicted failure point by 25%.

When making a decision between conducting owner and contractor mining, it is common for the mine owner to take into consideration a number of factors to assess the suitability of either method for any particular project. This research identifies and investigates the key factors by means of literature review and questionnaires and interviews with representatives from the resource industry across all fields - mine owners, contractors, independent consultants and Original Equipment Manufacturer (OEM)’s. The responses from 12 professionals were synthesized and compiled to form a framework that can assist both the mine owners in the decision-making process and representatives from other fields to have a better overview of a particular project in the context of owner vs. contractor mining. The key factors identified are company factors (expertise and availability of capital and personnel/workforce), geology of the deposit, geographical and political variability, availability and suitability of contractors and project’s financial model and investment analysis. The research shows that there does not exist a single methodology used across the industry and that the decisions are case-specific and should consider the balance between risk, cost and benefit.

 Ironmaking in the blast furnace is a rather complex process, governed by the generation of multi-phases and fluid-flow conditions. It includes the reduction of iron ore pellet or sinter material towards producing metallic iron. The metallurgical behaviour of sinter and its reduction rate are controlled by its initial physical and chemical properties, as well as the blast furnace gaseous conditions. To improve and optimize the metallurgical performance of sinter for ironmaking, it is necessary to understand the fundamental mechanisms of phase equilibria, microstructural transformations and reaction kinetics as relevant to different sinters in the upper shaft down to the reserve zone of the blast furnace. The objective of the present MSc research is to study the sinter solid state reduction reactions that take place in terms of thermodynamics and metallurgical kinetics when varying the initial material composition under certain temperature and gas atmosphere conditions.
 Six pilot scale sinter materials with strongly variable bulkmineralogical and chemical composition were sized down to fractions of 250-500μm,being a grain range adequately fine to isolate microstructural effects, whileexcluding the impact of meso-porosity and mechanical fractures (>1 mm), as practically aspossible. A industrial sinter sample, obtained from the production lineof Tata Steel Ijmuiden was included in order to verify potential differences inreduction. The starting materials were characterized with XRD, XRF, sizedistribution and BET measurements.
 Thirty six (36) isothermal reduction experiments were performed in the TGA and GERO furnace under two set of conditions; i) T=750^oC/XCO=0.55/N₂=0.5, ii) T=950^oC/XCO=0.65/N₂=0.5 simulating point-conditions of the BRASS test, as relevant to the stability field of Wüstite and solid state reduction. The reduction experiments were interrupted at different reduction times. The 36 reduced samples were further analysed with XRD for phase quantification to then be placed in polished sections for microscopical analysis. The materials were examined under Reflected Light Optical (LOM) and Scanning Electron (SEM) microscopes in order to verify microstructural changes, visualize phase transitions and identify existing stable and meta-stable phases. In total 396 microscopical images were produced. The results of the experiments were compared with thermodynamic models, which show which phases and reduction degree are theoretically expected at equilibrium.
 Hereby,based on research results, the study attempted to give answers to the initialreseach questions in order to confirm or deny the research hypothesis. The mainfindings of the study were mostly qualitative, referring to the mineralogicalchanges observed during reduction and their impact on reduction kinetics.Results verified that starting composition and mineralogy influencesreducibility kinetics, while the way minerals impact reducibility is dependedon the imposed conditions. It was observed that at T= 950^oC/XCO=0.65/N₂=0.5, the differences between the reduction rates of low and high basicitysamples become smaller, due to enhancement of the relative reduction progressof minerals like precipitated Magnetite. At T=750^oC/XCO=0.55/N₂=0.5,the transition of Magnetite to Wüstite occurred in different stages ofreduction progress, amongst samples. In addition, the effect of mineralogy and microstructure could not be distinguished ofthat of open particle porosity.

 Findings obtained from the XRD analysis andmicroscopy verified that Hematite is the most pronemineral to reduction followed by SFCA, while Magnetite stays stable for longer.Even within the samemicrostructure, Hematite is clearly reduced to a greater distance from theparticle exterior than the Ca-ferrites surrounding it, and its normalizeddecrease in the XRD analyses from its initial concentration is clearly fasterthan that for any of the Ca-ferrites (SFCA, CF2). Moreover, the relative reduction of Hematite and SFCA differsbetween the two sets of conditions; More reducing conditions converge thereduction progress of the two phases, due to SFCA’s greater reduction. The reduction fronts of Hematite and SFCA converge in a single sinter particlewith higher temperature conditions.Two types of unreacted SFCA wereidentified under the microscope, one Fe-rich SFCA and one Ca-Al-rich SFCA. SFCA1 starts reducing into a multiphase intergrowth, comprised by an Fe-rich pathand a Ca-Si-Al -rich path, while the high Ca type SFCA demonstrates one -to-onephase transition.

The reduction experiments inthe GERO showed that longer-time experiments always give the same samplesequence based on reduction progress; WCS108 is the most reduced, followed byWCS90, WCS86, the industrial sinter MH1785, WCS62 and WCS94, whilst noparticular differences were observed in reduction behavior of the industrialsinter MH1785/21 compared to pilot-pot sinter samples. In addition, the comparisons between the reductionexperiments and the thermodynamic predictions showed that there is mostly qualitative agreement, but results differ quantitatively.

Finally, based on the  findings of the research work conducted, the study hypothesis was confirmed; Sinter microstructure and mineralogy influences sinter solid statereduction.