The growing volume of end-of-life (EoL) photovoltaic (PV) panels presents a significant challenge and an opportunity for sustainable resource recovery. This thesis investigates the application of Magnetic Density Separation (MDS) to recover and separate valuable non-ferrous metals, such as silicon, copper, zinc, tin, and silver, from crystalline silicon PV waste. The objective of the study is to evaluate the separation efficiency and recovery rates of MDS while addressing economic feasibility and process optimization challenges.
The experimental work involved the use of MDS to fractionate PV waste into light, medium, and heavy-density ranges based on particle size distributions: 200–500 µm, >500 µm–3 mm, and >3 mm-6 mm. X-ray fluorescence (XRF) was employed to analyze the elemental composition of the separated fractions, with leaching processes using hydrochloric acid (HCl) and citric acid applied to assess the purity of magnetic samples. Calibration and instrumental errors, as well as the effects of alloying and particle motion, were accounted for in the analysis. A financial assessment of the MDS process was conducted, examining revenues generated from metal recovery and associated costs, including the economic implications of contamination and refining. The results revealed that MDS achieved moderate separation efficiencies, with high recovery rates of silica (SiO2) in the form of glass and sand in the light fractions and silver (Ag) and copper (Cu) in the heavy fractions. However, significant contamination was observed due to overlapping densities of alloyed metals, such as Tin-silver-copper (Sn-Ag-Cu) and Zinc-copper (Zn-Cu), and particle agglomeration during feeding. A financial snapshot demonstrated that medium- and large-sized fractions contributed the most to revenue, driven by silver recovery, with a break-even point requiring the processing of at least 114 tons of PV waste. In conclusion, MDS shows significant potential as a low-energy, cost-effective solution for recycling EoL PV panels. However, achieving industrial viability requires addressing contamination issues and optimizing the separation process. Future work should focus on integrating complementary refining techniques and scaling up operations to meet purity standards and economic demands. The study also recommends the need for improved ferrofluid magnetization and alloy-specific calibration to enhance detection limits.

Vanadium is a heavy metal and is reproductive and developmental toxic for mammals. Therefore, Tata Steel Nederland should prevent vanadium emissions from entering the groundwater. Consequently, a good understanding of blast furnace burden feed material’s microstructural development and phase transformations is required. This thesis aims to investigate how the distribution of vanadium in iron ores changes when these are processed into pellets and how this affects the leaching potential. Therefore, a semi-quantitative approach is applied, using different analytical techniques, including XRD, SEM-EDS, LA-ICP-MS and leaching tests.

The results show that vanadium is initially hosted in the spinel structures of the magnetite iron ores. A secondary melt phase is formed during firing, where the vanadium is partially transferred to from the iron oxides. The amount of vanadium is controlled by the basicity of the pellets and the oxygen fugacity during firing. This melt phase is likely susceptible to vanadium leaching.

In conclusion, this research showed how the distribution of vanadium changed during the pelletization process. Further research is recommended to perform this study on sinter blast furnace feed material, study the influence of the oxygen fugacity in more depth, perform a more extensive leaching study and research how the leaching of vanadium from pellets can be prevented.

The growing importance of rare earth elements (REEs) in sustainable technologies necessitates anefficient assessment of potential resource targets within the European Union. Traditional analyticaltechniques for REE determination have drawbacks like destructive and time-consuming samplepreparation, but hyperspectral imaging (HSI) and laser-induced fluorescence (LiF) offer promisingalternatives. This project aims to use a combined HSI and LiF method to qualitatively characterizeREE mineralization and alteration in drill core samples from the Storkwitz deposit, Germany. The goal is to develop a transferrable mapping approach for REEs, while enhancing our understanding of the Storkwitz deposit. It aims to check the robustness of HSI conducted across the extendedwavelength range as a tool in effectively characterizing the lithologies associated with REEmineralization in the Storkwitz breccia. It also tests if the combined HSI-LiF can provide newinsights into the presence of REEs and its associated minerals in the Storkwitz breccia.The proposed workflow involves acquiring hyperspectral data of the Storkwitz drill core and blocksections in three wavelength ranges (VNIR-SWIR, MWIR, and LWIR). Automatic and manualendmember extraction is performed on the smaller subsection of data to create spectral libraries,which are then used for spectral unmixing and mapping of the entire hyperspectral dataset toidentify lithologies. LiF is used to identify and map rare earth elements (REEs) in selected REErichzones identified from the hyperspectral data.The results indicated that the Storkwitz Breccia is primarily composed of ankerite in the matrix,along with minor amounts of white mica, clay, iron oxides, and REE-fluorcarbonates. The brecciacontains different clasts, including granitoid clasts rich in orthoclase and quartz-albite-biotite, aswell as carbonatitic clasts dominated by ankerite, dolomite, and ankerite-calcite. The breccia alsounderwent four alteration phases, including fenitization, biotite alteration, white mica-clayalteration, and ferric alteration. Laser-induced spectroscopy confirmed the presence of REEs, withapatite and REE-fluorcarbonates, particularly bastnäsite, being the main REE-bearing minerals.The specific REEs identified include Nd3+, Sm3+, Pr3+, and possibly Eu3+. The comprehensiveworkflow combining hyperspectral imaging and laser-induced fluorescence spectroscopy provedto be a successful approach for characterizing lithologies and mapping rare earth elementmineralization in the Storkwitz breccia. The study opens up new possibilities for efficient REEexploration in similar geological settings, providing valuable information for geological loggingand interpretation.

The importance of decarbonization in various industries is growing significantly, especially when it comes to LHD equipment in the minerals and metals industry. Conventional diesel load and haul (LHD) equipment used in quarrying and mining operations have drawbacks that result in the emissions of hydrocarbon and greenhouse gases that need to be reduced to reach the Net Zero Emissions scenario. Decarbonization options that could replace diesel equipment include battery electric vehicles, green hydrogen, and alternative fuels. This project aims to give an overview of current and near future available decarbonization methods and to analyse the environmental benefit, cost effectiveness and technological feasibility of these alternatives to diesel fuel. The case study used to simulate and compare the three different decarbonization options is a mountaintop marble quarry based in Ipoh, Malaysia. A comparison has been made with Ipoh located in Malaysia and a hypothetical situation of Ipoh located in France to show the true potential of decarbonization as Malaysia does not incentivize businesses to reduce emissions due to their subsidies on the use of fossil fuel. Malaysia’s energy mix consist of primarily unabated fossil fuels.
The proposed workflow involves an extensive literature review of current and near-future decarbonisation technologies to replace diesel equipment and to create a haulage network based on block model data using the software Xpac Quarry solutions and its Haulnet package. Diesel equipment is imported from the Quarry solutions database and used as a base case to compare BEV and trolley assist simulations. Hydrogen and HVO fuel consumption have been calculated manually to obtain NPVs and associated emissions. An investigation into required infrastructure and energy requirements has been done to accurately define costs and resulting total CO2eq emissions.
The results indicate that replacing diesel at Ipoh with any of the decarbonization methods will result in a negative NPV as the infrastructure requirements need extensive capital investment of which the payback period often exceeds the life of mine. The least expensive method to implement HVO fuels, followed by BEVs and green hydrogen. Furthermore, it has been found that using BEVs instead of diesel at Ipoh is more environmentally polluting because producing 1 kWh of electricity is more polluting than producing the same energy worth of diesel. Green hydrogen is the least polluting method with no greenhouse gas emissions associated with it, followed by alternative fuels. When investigating the technological feasibility of the three main decarbonization options, hydrogen is the furthest away of being technologically feasible as from now. No green hydrogen using water electrolysers has been produced at an industrial scale, and a lack of technical expertise and infrastructure is present regarding distribution, transportation, and storage. Currently, no hydrogen LHD equipment is commercially available currently, and the same applies to BEVs that could replace the current equipment used at Ipoh. To bridge this gap, alternative fuels are the best option, but the market is competitive, and supply is limited. This project has given a good overview of current possibilities and clearly shows today’s options for decarbonisation and where industries stand with respect to infrastructure and equipment.

Haul truck driving remains to be the most dangerous occupation in the mining industry (Kecojevic et al., 2007), leading in fatalities over other occupations in the mining industry. As the transition to autonomous haul trucks over the coming decades will not address thisproblem today, an immediate solution is needed that can be adopted at short notice to help aid in minimizing haul truck accidents. A gamified training simulator was developed that teaches haul truck drivers how to handle the hazardous situations that lead to the most injuries in the mine environment. The simulated nature of the training method allows truck drivers to gain knowledge on hazardous situations and immediately put them into practice by applying the gained knowledge during the different levels. Gamification aspects like a score system and progression through levels were added to increase engagement during the training simulation.
A statistical analysis was made on haul truck accidents from 1983 until 2022. The accidents that proved to be most relevant were included in the content of the training software. A training software was developed using Unreal Engine 5, where trucks could be driven using a Thrustmaster T150 Pro steering wheel and driving pedals. 18 participants from ages 19-65 underwent the training program and two tests of identical difficulty were taken before and after undergoing the training, in order to make a judgement on the progress of the participants by undergoing the training simulation. Participants were judged based on the number of crashes and traffic violations committed, attempts required to complete the test, as well as the time taken to finish the test. A score was calculated based on these factors providing an overall judgement of the participants’ level of skill.
Average skill of participants increased by undergoing the gamified training, and training showed particularly good progress for underperformers in the initial test. After completing the gamified training the average score of participants was notably higher and the standard deviation was notably lower. It was concluded that all participants were brought to a comparably high level after completing the training.

The mining industry is a significant contributor to greenhouse gas emissions and operational costs. The transportation of materials within mining operations, especially using diesel-powered trucks, accounts for a substantial portion of both emissions and costs. Optimizing fuel consumption in this context is crucial for environmental sustainability and financial efficiency. While there is some existing research on minimizing fuel consumption in mining operations, most of these studies prioritize production over fuel efficiency. Additionally, there is a lack of solutions addressing real-time dispatch problems while also minimizing fuel consumption. This thesis proposes the development of a model to optimize truck speeds in mining operations, with the primary goal of reducing fuel consumption. The focus is on minimizing waiting times for trucks at loading stations by adjusting their speeds using a metaheuristic algorithm, specifically Simulated Annealing (SA). To achieve this, a discrete event simulation (DES) model made in HaulSim to replicate a simplified mining site in Nevada, USA. The simulation includes Caterpillar 793 series trucks. The SA algorithm is applied to find optimal truck speeds, with the aim of reducing fuel consumption with the same level of production. The hypothesis is that lowering truck speeds in mining environments with queueing trucks can significantly reduce fuel consumption. The study explores how speed optimization impacts efficiency across different mining conditions, identifies the most effective optimization techniques, and quantifies potential fuel savings. The research reveals a 27-32% reduction in fuel consumption across various truck scenarios. However, these findings should be interpreted cautiously due to limitations in data constraints and modelling simplifications. In conclusion, the study highlights the effectiveness of SA in optimizing truck speeds and the potential for substantial fuel savings in mining operations. We recommend the integration of Artificial Neural Networks (ANNs) for a more nuanced approach to fuel consumption estimation and optimization, considering factors like road maintenance intervals and payload. This synergistic approach, combining metaheuristics and machine learning techniques, aligns with sustainable practices in the mining industry and offers promising avenues for further research and application.

In the former lignite mine "Robertshall" near Hamburg damage to the surface was caused by the collapse of underground cavities originating from old mine workings of a lignite mine which had been in operation between 1920 and 1922. During the investigation of the subsurface by drilling it was noticed that the existing mine plans are incomplete.
If mine plans are missing or incomplete, the risk to protected assets at the surface due to mining damage can often only be reliably assessed by means of indirect methods such as geophysics in reasonable combination with drilling. Within the scope of this work the extend of room-and-pillar caving at the “Robertshall” deep lignite mine was determined by geophysical methods. Subsequent backfilling and securing of the old mine workings are the goals of this exploration.
The simultaneous application of several methods on the selected test profile is not only intended to increase the reliability of the results, but also to gain experience as to which methods are best suited for routine detection under the given geological and mining conditions. The geophysical measurements are supplemented by an evaluation of historical data.
The results of geophysics have led to the prompt and reliable discovery of many drifts that were not included in the mine plan. Compared to the conventional approach of exploration by drilling, the application of seismic measurements saves time and costs.
The securing measures could be carried out by the responsible parties and the desired securing success has been achieved so that no further movements of the ground surface are to be expected.

The electrification of the world and the green transition are expected to increase the demand for energy storage technologies such as lithium-ion batteries. This will increase the demand for raw materials used in batteries, such as graphite. Further, due to geopolitical risk and the need for sustainable sources, graphite mining is also of interest in Europe and nations like Finland. During the concentration and/or refining of ore, an enormous amount of waste is produced due to the low concentration of the desired element. Some of the material of interest ends up in these side streams, as for example, in the tailings. However, the waste can potentially be used as a secondary source of raw materials.

In this work the potential processing scenarios of graphite mine tailings were inves-tigated. The studied tailings samples originated from pilot metallurgical test work done in Canada with Aitolampi graphite ore. According to the analysis results, the tailings contain high concentrations of sulfidic sulfur and heavy metals, posing a potential risk of acid mine drainage. In this work, the potential strategies for harmful elements removal were studied and advantages and disadvantages were evaluated. This thesis work included magnetic and gravity separation test work done for tailings samples. Additionally, leaching experiments with varying acid molarity, temperature, and solid-to-liquid ratio were conducted.

Based on the results, with a low-intensity magnetic separator, 58–64% of sulfidic sulfur could be recovered. Additionally, the magnetic product is theoretically suitable to be used in sulfuric acid production. Further, with gravity separation, the grade of Ni, Co, Cu, and Zn could be increased by a ratio of two to three. By leaching experiments, the leaching orders of the sulfide minerals pyrrhotite, sphalerite, chalcopyrite, and pyrite were confirmed. However, the concentrations of Co, Ni, Cu, and Zn in the tailings were too low, and Fe was too high to be economically attractive, so that recovery utilizing only leaching would be economical. This suggests that low grade tailings will still require technological innovations to achieve concentrates suitable for state-of-the-art refining.

Starting from the 1950s, plastic has found its way into many aspects of life; from packaging to transportation and construction. The annual global plastic production was estimated to be 330 million metric tons in 2017 and will be doubled within 20 years if the current growth rate persists. In Europe, packaging accounts for 40% of the annual plastic production. To decrease dependence on fossil fuels and the related emissions and reduce the negative impact of plastics that enter the environment, the EU targets to recycle 55% of plastic packaging material by 2025. A steady production of large quantities of high-grade plastic recyclate is essential to sell the recycled material on the market and substitute virgin plastics.
But, achieving this high grade is difficult due to the wide range of polymers, including additives and fillers. This research focuses on the sorting step of post-consumer packaging waste in a Material Recovery Facility (MRF) that takes place before recycling.

In MRF's, Near Infrared (NIR) sensor-based sorting systems are state of the art to create high-grade sorting products. NIR's use reflection spectra to identify and distinguish a range of materials including different types of polymers. However, while sorting, False Calls (FC) occur when particles are incorrectly classified leading to a loss of valuable material or contamination of the product. Thus, this research aims to increase the understanding of false calls of NIR sensor systems, contributing to higher quality sorting products.

To reach this goal, possible causes of FC's and their dependencies on the feedrate, feed composition and feeding mechanism were identified. These causes were arranged into a framework consisting of six types of FC's. A distinction was made between errors that are working range related and those that are not. Particles outside the working range may be classified incorrectly even when fed in a monolayer and under perfect circumstances due to the properties of the particle.

The created framework was applied to a NIR in an MRF in the Netherlands which was tasked to separate non-plastic particles and PVC from plastic particles. Experiments were performed to single out the probability of each type of error to occur for 13 material classes. Next, the test results were implemented in a statistical model and a Monte Carlo simulation was performed. In this research, the varying input values were used to imitate the changing feed composition. Three scenarios of adjusted feed characteristics were analysed using the statistical model.

It was concluded that to optimize the sorting performance of the analysed NIR, all types of False Calls should be tackled. The feed of the analysed NIR contained a large share of particles outside the working range. So, even if the particles were to be fed in a monolayer the average grade of the product is expected to be around 85%. The combination of the experiments and the statistical model allows for an effective evaluation of the sorting performance and a clear indication of the most problematic aspects of the feed characteristics.

Aluminium is a vital component of the world's economy, thanks to its versatile applications. However, the environmental impacts of primary production result in a growing desire and societal pressure to develop more efficient recycling techniques. Secondary aluminium is produced at 5% of the energy consumption used to produce primary aluminium. Unfortunately, many recycling techniques suffer from an undesired loss in quality and material due to the complex particle shapes, variety of alloys, and contaminants. This research focuses on a state-of-the-art scrap sorting technique that aims to overcome the problems associated with the singulation of particles with sizes up to 500mm (max. diameter). Singulation is the process where a random particle flow is regularized into an individually spaced 1D file of particles. Subsequent particle identification and sorting into multiple categories increases scrap quality to allow for more efficient up-cycling. A combination of literature study, model simulations and setup experiments is used to study the effects of particle- and equipment properties on obstructing processes. Firstly, this study focuses on three particle properties: Length-to-Width (LW) ratio, density, and complexity of shape. Four different samples are studied: Base case, high LW, high density, high complexity of shape. Obtained results show the adverse effects of increased LW-ratio on the singulation performance. An average LW-ratio increase from 2 to 6 decreases the singulation performance by 10-15%. Surprisingly, the expected frequent entanglement of complexly shaped particles was seldom observed. In addition, the flow of complexly shaped particles showed similar singulation rates compared to low LW particles. High density particles were only linked to minor obstructing events. Secondly, this study focuses on obstructing processes by studying the particle flow over and between setup equipment. Two processes are the most important: 1) transition behaviour (single particle flow) and 2) merging mechanisms (multiple particle flow). Video analysis has shown the adverse effects of unpredictable particle flow upon transitioning between setup stages. This results in an entirely random process, thereby deteriorating performance and rapidly wearing the chute surface. Unpredictable flow on the chute is primarily related to specific yet frequent circumstances. The amount of correction in flow a particle requires to align into a single file seems the best indicator. Centre-fed, parallel orientated particles require the least correction. Edge-fed, perpendicularly orientated particles require most. The latter is associated with the highest degree of unpredictable rolling. This observed phenomenon increases with particle size. The chute is designed to merge particles with crossing trajectories. Merging particles rotate around their point of contact as a whole until the combined bounding box is orientated parallel to the direction of flow. This explains the poor performance of high LW particles and surprisingly good performance of complex-shaped particles. The bounding box of merging high LW particles is already orientated parallel to the direction of flow. Limited rotational force is therefore exerted on the particles. In addition, the higher moment of inertia and chute design further restrict rotation towards sequential flow. Consequently, the current singulation process functions below its potential. The passive singulation process benefits from a reject of high LW particles towards the coarse faction (to be re-shredded) and smooth transition designs to reduce unpredictable flow.

Ammonia has been recognized as an effective leaching agent in hydro-metallurgical processes for the recovery of metals\cite{AmmLeach2013}. These processes result in ammonia-metal crystals, whereby in the last step, water and ammonia are removed from the crystals by a calcination process. In the past, the vaporized ammonia is considered a waste stream. However, regulations in the last few decades make it impossible for companies to dispose large amounts of ammonia into the air\cite{LRTAP2005}\cite{SOER2020}. Therefore, expensive installations, like catalytic oxidizers (CATOX) or membrane separators, need to be installed for ammonia reduction in the effluent gas stream. Climax Molybdenum b.v. installation in the Botlek Rotterdam produces pure molybdenum oxide according to the process described above. With the production, molybdenum oxide is leached in an ammonia solution to remove all contaminants, then crystallized and calcined. For the calcination process, the crystals are heated by a gas burner to vaporize the ammonia and water. The off-gas contains air, \ce{NH3}, \ce{CO2}, dust particles, and water vapor. The objective is to recycle the ammonia from the off-gasses of the calciner. Reclaiming the ammonia from the off-gas stream could reduce the costs up to \euro2000 per day. In this thesis, insights are gathered related to the chemical and physical reactions that occur when off-gasses of the calciner enter the process. Additionally, both the beneficial effects and potential complications of reclaiming ammonia from the off-gas are explained. This research is conducted by making mass balances on three different options for off-gas handling. These options include absorption into the leaching fluid (ARS:Ammonia Reduction System), absorption by water through a scrubbing system (AER:Ammonia Emission Reduction), and absorption by water through a scrubbing system with additional carbon dioxide removal with sodium hydroxide (AER+NaOH). In order to understand what happens when inorganic carbon (IC) comes into the system, experiments are conducted on both the leaching procedure of molybdenum and the stripping and condensing process of ammonia. Results show that inorganic carbon reaches its solubility in the leaching fluid at 2.12 mol/kg. Also, no effect on the solubility of ammonium molybdate was found, and no additional precipitation occurs on metals like zinc, calcium, magnesium, and iron. In the leaching fluid, the solubility of ammonium bicarbonate is reached at 183 grams per liter. Additionally, the influence of inorganic carbon on the stripping process showed that the strip rate of ammonia was reduced by 1.4. Also, could be concluded that stripping of ammonia was done efficiently at 80 degrees until the total ammonia nitrogen (TAN) mole concentration equals the total inorganic carbon (TIC) mole concentration. As a result, additional water treatment is needed for the discharge water to ensure the amount of ammonia does not exceed 25kg per day. Furthermore, another complication found was scaling. Scaling happens in both ARS and AER-system in the form of ammonium bicarbonate. In contrast, AER+NaOH system does not have the complication of scaling or ammonia in the discharge water, but the pH of the solution needs to be neutralized before discharge. Moreover, higher pH in the recycling water of the scrubber causes lower absorption efficiency of ammonia. ARS, AER, and AER+NaOH-system have an ammonia reduction of 41\%w, 33\%w, and 73\%w per day, respectively. For the ARS and AER-system, this means a cost-saving of \euro{1.160,-} and \euro{920,-} per day, respectively. The AER+NaOH-system has a direct cost of \euro{10.130,-} per day, due to the expensive sodium hydroxide. The cost of sodium hydroxide as a water treatment agent is higher than the cost savings of ammonia recovery from the off-gasses of the calciner. Therefore can be concluded that, ammonia recovery from off-gasses has large potential, but other methods are needed to treat ammonia in the discharge water to make it economically feasible. Further research can elaborate on alternatives for ammonia treatment in discharge water. Examples include the use of lime (CaO)\cite{AdPhysicochem2006}, increasing the stripping temperature\cite{Kim2013}, and leaching in sulfuric acid (\ce{H2SO4})\cite{EICforEngin2017}. However, this does not solve the scaling problem in the process. Therefore, further research should shine a light on the reduction of carbon dioxide that enters the chemical plant system. Examples proposed in this research, include condensing ammonia from the calciner off-gas stream. Multiple studies \cite{Xu1999}\cite{Mirl2020} show that, the condensing recovery is more effective for ammonia than carbon dioxide. Furthermore, this research also gives an economically feasible example of using an alternative calcination process without natural gas.

Site-specific calibration of laser induced breakdown spectroscopy (LIBS) analysis can be achieved by presenting known geological sample data to update algorithms, therefore improving analysis of unknown samples post-calibration. The goal of this project is to optimise drill core analysis by LIBS for samples from Kittilä gold mine. In total 227 samples have been produced and analysed with a range of analytical techniques to build a comprehensive, site-specific reference library. The data from these analyses has been input into the reference library and utilised by algorithms for spectral peak identification during LIBS analysis of bulk drill core material. The semi-quantitative and quantitative data of 40 Kittilä samples has been used as a comparison to ICP-AES data used by the mine. The Kittilä powders were used to produce 39 pellets, each representative of a section of drill core of which the ICP-AES and TXRF data was known. The pellets were scanned by LIBS and the data then compared to the known data. LIBS showed strong correlations (>0.75) with ICP-AES data for As, Cr, Cu, Fe, Mn and S, poor correlations were seen for Pb and Co, however these can be explained by issues related to ICP-AES. LIBS pellet data proved strongly competitive as 5/9 elements displayed stronger correlations between LIBS and ICP-AES than TXRF. Subsequently, the successful scanning of drill core boxes directly has proven that calibration can increase the speed with which the bulk material can be effectively analysed.

This research was aimed at determining the influence parameters have on the cut-off grade of sublevel stopes in the Garpenberg underground mine, and combing these to maximise value at the mine. Garpenberg is a multi-deposit poly-metallic mine owned by Boliden AB. Cost calculations were performed on data from 2018 to derive costs for each deposit and activity. Ore transport and rock bolting were two parameters which were suitable to be used for variable cost implementation. These costs were assigned to the different orebodies and cut-off grades were adjusted to reach a break-even level. Stopes were created using the Stope Optimizer software in Deswik, using the variable cut-offs and the technical constraints previously used for Garpenberg's Life of Mine Plan. Cut-offs were elevated or depressed to optimise NPV for each deposit separately and the optimal combination yielded an NPV increase of 530 Mkr, a 4\% increase, compared to using static cut-off grades. More value can be obtained by combining cut-off strategies in Garpenberg as whole, in contrast to separate optimisation. Scheduling of newly created stoping areas within the Lappberget deposit proved to be beneficial for value. Finally, a financial analysis into double stopes of 50 m high was performed. The elimination of production levels provides the main cost reduction. However, lower selectivity and expected dilution will limit the financial gain from this method.

Phosphate is removed from wastewater to prevent eutrophication. Chemical phosphorus removal by iron dosing is commonly used for this purpose, where phosphorus is among others bound in the mineral vivianite (Fe(II)3[PO4]2 · 8 H2O). A molar Fe:P ratio of 2.5 in sludge will capture 70-90% of total phosphorus in vivianite after anaerobic digestion, a digestion method which offers ideal conditions for vivianite formation. Vivianite is paramagnetic, enabling it to be recovered by magnetic separation for recycling purposes. Phosphorus recycling from wastewater is of great importance, as in worst-case scenarios, 40-60% of all phosphate rock resources will be extracted by 2100. It is furthermore estimated that in Europe 20-30% of the fertilizer demand can be met by using phosphorus that ends up in sludge in European sewage treatment plants. To reduce processing costs of magnetic vivianite recovery, a pre-concentration step based on density concentration can be introduced, as vivianite particles are denser than organic material in sludge. This research investigated the feasibility of vivianite concentration from digested sewage sludge with a Multotec MX7 spiral concentrator. Spirals are applied in the mining industry for coal washing and pre-concentration of ores which are suspended in water. Particle separation on spirals is based on centrifugal and gravitational forces. Digested sewage sludge is more viscous than water, which affects the separation process on spiral concentrators. To investigate the influence of this high sludge viscosity on the spiral separation efficiency, laboratory experiments were performed. Diluting the sludge furthermore improved the concentration of solids towards
the product flow. However, spiral efficiencies were only 9%, while efficiencies over 80% were found for synthetic sludge, meaning that particle separation was limited. The iron concentration was highest in the product outlet and increased with dilution. The phosphorus content, however, was similar for all outlets and dilutions, suggesting that only Fe minerals other than vivianite, such as siderite and pyrite, concentrated towards the product flow. Additionally, a concentrated bed of sand grains was observed near the column after a dilution of 20%. While diluting the sludge improved the concentration of sand and heavy Fe minerals, it did not induce vivianite concentration.

Irreversible damage induced by stress in brittle rock is accompanied by the formation of micro-cracks. The strain energy released during the fracturing process is released in the form of acoustic emission. This thesis applied the non-intrusive method of acoustic emission monitoring to assess the deformation process of brittle rock during cyclical loading and loading to failure in a standard uniaxial compressive strength test set-up. It is confirmed that the stress-strain curve is clearly separated into five phases and that the cumulative hits recorded throughout the failure process correspond with these five phases. Furthermore it is found that there is an obvious rise in trend in the amplitude of the acoustic events as the rock nears failure, but that individual events of high amplitude should not be considered indicative for the damage in the rock. Additionally it is found that high amplitudes characteristic for near failure stress are recorded at 25\% of the failure stress if the rock has been under high stresses, indicating a change in fracture mode. The Kaiser Effect, the phenomenon defined as the absence of detectable acoustic emission events until the load imposed on the material exceeds the previous applied level, was confirmed during uniaxial cyclical loading. Through loading samples from a highly stressed pillar in the Nepheline Syenite Stjernoya Mine in Norway, it is found that the onset of acoustic emission may be indicative of the stress in the pillar. These findings are useful to further develop acoustic emission as a monitoring method in a range of applied earth science applications.

The main waste products of ironmaking at Tata Steel IJmuiden are CO2¬(g) and a solid waste stream consisting of mainly carbon and iron-bearing compounds. This solid waste is generally called Zn rich filter cake which contains too much Zn to be reintroduced into the iron making process. Besides Zn, Pb and Cd are also present. These filter cakes originate from the flue dusts that are expelled from the top of the blast furnace. Currently the solid waste is separated based on size distribution which allows the recycling of most of the materials and concentrates the heavy metals into the Zn rich filter cake. Previous research has shown that these cakes are resistant to regular leaching methods for selectively dissolving the contained heavy metals. This is due to their sulfide form. The methods that do work (such as acid leaching) also dissolve additional material such as iron, which is the main component of the waste stream. Therefore Tata Steel Europe is investigating whether alternative options are available to selectively extract these heavy metals and reintroduce the remaining material as secondary ore back to ironmaking.

In this research the option of adding oxidants with and without additional microwave treatment is investigated. Based on what is applicable in reality, literature and thermodynamic evaluations several oxidants were selected to oxidize the metal-sulfides to metal-oxides which can be readily leached in ammonia based media. Furthermore the material was characterized and an investigation was done on where the sulfur originates and whether this stream can be reduced or avoided. The quality of the results was verified by comparing the heavy metals dissolved into the leaching solution by ICP analysis and by determining the heavy metal content in the solid material before and after leaching with XRF. It was found that 98% of the sulfur originates from the blast furnace and only 2% from the addition of sodium sulfide at the water cleaning department.

Leaching experiments were done with a 40 °C leaching solution, a 5:1 liquid to solid ratio. Leaching solutions were all ammonia based due to its selectivity to heavy metals. Leaching the sample material without microwaving or addition of oxidants the highest Zn, Pb and Cd recovery was 54%, 0.5% and 24% respectively. Potassium permanganate as the oxidant resulted in the highest extraction of Zn at 67% in a 2M ammoniumsulfate, 9M ammonia leaching solution. Ferric chloride in a 2M ammoniumsulfate, 9M ammonia leach solution reached extractions of Zn and Cd at 64% and 45% respectively for the IJmuiden filter cake. For Pb the best extraction was 5% in a 2M ammoniumcarbonate, 9M ammonia leach solution with the same oxidants. Microwaving the sample during leaching resulted in a higher extraction for both Pb and Cd, whilst matching the non-microwave oxidant leaching extraction for Zn. The highest extractions were 61%, 42%, 83% for Zn, Pb and Cd respectively. Aging has also been proven to have an detrimental effect on the extraction of heavy metals, however the aging effect is negated when using microwave treatment or oxidants. Extractions for lab reactor leaching of fresh samples without added oxidants or microwaving with an ammonia sulfate solution, resulted in extractions of 62%, 0%, 40% for Zn, Pb and Cd respectively.

It has been verified that most of the sulfur comes from the blast furnace. Further it has been reaffirmed that the metal sulfides this sulfur forms are difficult to leach out. One study states that metal sulfides can and will form in the blast furnace. The current study supports that, even though no direct study of the blast furnace itself was done. Oxidants and microwave assisted leaching seem to work well for Pb and Cd, but are less effective on extracting a higher percentage of Zn. It is recommended to use this method in combination with another process, a different ironmaking process such as HIsarna would be preferable due to the reduction of ZnS to ZnO which is readily leached with an ammonia leaching solution.

The heterogeneity of layered systems leads to variation in rock or soil mechanical properties, influencing the resistance to failure. A formation breaks by fracture propagation when the effective stress surpasses the formation strength. The propagation of a fracture through a mechanical interface depends on whether the formation strength of the second formation is overcome. This critical effective stress level could be trespassed by high natural or industrial induced pore pressures. Understanding fracture propagation in multi-layered systems with variable pore pressure regimes has important implications and applications to many industries such as quarrying and hydraulic stimulation. The slope stability of Westerwald Clay Quarries is influenced by inter-bedding of thin sand layers. Surface and slope fractures within the clay formation originated from a high observed hydrostatic head within the sand layers and a reduced confining stress from mining activities. The slopes of the quarry are key in determining the volume of economically mineable clay, these slopes are in turn controlled by the size/extent of fractures and whether they extend through multiple formations. This study examines the effect of fracture continuation from sand layers into the stiff Westerwald Clay Formation. The soil parameters (cohesion and friction angle) of the different lithologies within a Westerwald Clay Quarry are determined for slope stability analysis by shearbox testing. Soil classification has been done in terms of plasticity, grain size and mineralogy by Atterberg Limits, Sieving and XRD & XRF respectively. The results show that fracture initiation within the Westerwald quarries is a combination of mining activities lowering the confining stress and a constant natural hydraulic head. The hydraulic head within the small sand formation lowers slope stability by causing fracture initiation and water infiltration into the clay formation. Slope stabilisation occurs by artificial water pumping or natural water dissipation lowering the hydraulic head. Slope stability is decreased by embankments of low permeability backfill and increased by high permeability backfill. Inter-bedded systems are common target locations for an unconventional reservoir systems and can be found both within source rocks as well as in conventional geological traps. Improvement in recovery from these tight systems often depends on the extent and continuity of fractures through heterogeneous interfaces. This study examines the propagation and continuity of the fractures in an artificial heterogeneous layered system. The fractures will be initiated by hydraulic fracturing in a dried layered system via water injection in a triaxial cell. Fracture propagation is analysed through Micro-CT scans. The mechanical properties such as acoustic wave velocities, unconfined & confined compressive strength and tensile strength are all determined for the analysed layered systems. The results show that hydraulic fractures initiated within the weakest layer are arrested at the interface between a mechanically weak and strong formation, whereas fractures initiated within mechanically stronger layers prograde through the interface. Hydraulic fractures are initiated when local pressure difference at the interface exceeds the formation’s critical tensile stress, the formations critical tensile strength is dependent on the confining pressure.

Rationale - Increasing world population and consumption, and rising dependency on certain countries for the supply of raw materials lead to the demand for new raw material resources. This demand, combined with the increase in complexity of new land-based mining operations increases the chances for a viable offshore mining business case. Goal and scope - The aim of this research is twofold. The first aim is to fill knowledge gaps in the offshore mining value chain, with a focus on the processing of the mined material. The second goal is to assess if shallow water offshore mining is a viable business option. Explicitly left out of scope are the exploration for mineral deposits as well as the detailed or new design of an extraction method for subsea minerals. Furthermore, resources beyond the continental plate are not part of this research. Approach - To answer the first goal of this research, an extensive literature study is performed comprising an assessment of potential offshore mineable minerals and their respective markets. It also included an analysis of current land-based mineral processing techniques and its limitations in an offshore environment. Furthermore environmental, legislative and tax aspects were included as well as detailed descriptions of future offshore mining projects, and current dredge mining projects. To assess the viability of an offshore mining project, a case study is set-up of a prospective offshore mining project. A method for executing the case study is developed. Results of the case study - For the case study the mineral deposit has been studied and based on its mineral characteristics a location specific processing flow sheet is developed. The case study resulted in a set of execution alternatives, from which a preferred option was selected. Based on this option the viability of the project is assessed with the use of a discounted cash flow method (DCF-method). Conclusions - Main knowledge gaps are identified as the impact on the environment, and the lack of legislation regarding offshore mining. Furthermore, it should be noted, that the public opinion regarding offshore mining is important to consider as well.