Tungsten is listed on the European Commission list of critical raw materials that are crucial to Europe’s economy. By raising awareness of tungsten as a critical raw material the EU can prioritise to enhance exploration, mining and recycling of tungsten. In this thesis the structural relationship between wall rock and veins, in a greisen-tungsten vein deposit, were analysed with the intention to interpret how tectonic deformation events control the emplacement of tungsten-bearing veins. The objective of this thesis is to investigate if and how structures controlled hydrothermal fluid flow and ore formation in the Peña del Seo tungsten-greisen vein deposit. Greisen systems are associated with tin and tungsten-bearing minerals and are related to intrusive magmatic bodies of granitic composition. Greisen-related granites (leucogranites), form at shallow depths in the crust (1.5-4 km) generally in intracontinental tectonic settings such as orogenic belts. The study site is located in the West Asturian-Leonese Zone in northwest Spain. This zone marks the transition between the foreland and the hinterland and is recognized as being part of a continental margin, where Palaeozoic rocks were deposited unconformably. These rocks were subsequently subjected to folding during the Variscan orogeny (370-290 Ma). Three main types of structures were generated due to three deformational phases (D1, D2 and D3) during the Variscan orogeny. D1 resulted in east-verging recumbent folding and formation of a related axial-planar parallel cleavage (S1), D2 resulted in displacement along large thrust sheets and D3 produced upright folding and refolding of F1 folds. Geological mapping with a focus on structural geology was carried out in March 2019, covering an area of approximately 0.25 km2. Structural measurements and oriented rock samples for microstructural study in thin sections were collected in the field. Additionally, photogrammetric mapping of structures was performed on a 3D photogrammetry model derived from a UAS survey. The geometry of the Peña del Seo tungsten-greisen vein deposit is interpreted to result from two major deformation events. The axial planar foliation (S1) at Peña del Seo is correlated to the regional fabric that developed during D1 of the Variscan orogeny. The related F1 folds are caused by buckling accompanied by flexural slip folding mechanism during D1. Forceful intrusion of the granite underlying the Peña del Seo deposit caused bending of the overlying rocks layers during D2. Layer-parallel stretching is likely to have caused tension fractures perpendicular to bedding in the outer arc of the F2 fold hinge. The formation of local crenulation and related spaced cleavage can be explained by layer-parallel shortening in the inner arc of the F2-fold. Local transposition of S1-foliation occurred during emplacement of quartz veins and explains the different orientation of strike of foliation between the northern and southern parts of the area. Fractures forming during formation of F2-fold are likely to have worked as conduits for ascending hydrothermal, ore-bearing fluids forming the Peña del Seo tungsten-greisen vein deposit.

MESMEG / Department of Mining and Environmental Geology / Muyexe magnesite deposit is situated in the Giyani Greenstone Belt in South Africa. Despite mining activities currently taking place at Muyexe magnesite deposit, little information is available about the geology and geochemistry of the deposit. This has resulted in a gap of information about the nature and character of magnesite, namely; its geology, mineralogy, geochemistry and mode of occurrence. Consequently, there is a need for further investigation of the magnesite deposit. The main objective of the study was to establish the geology and geochemistry of the Muyexe magnesite deposit and to ascertain its mode of occurrence. Further work involved undertaking detailed geological mapping, magnesite and rock sampling for petrographic and geochemical studies using petrographic microscopy and X-ray fluorescence spectrometry and identification of minerals in rocks and magnesite through X-ray diffractometry. A total of 20 magnesite and 4 host rock samples were collected from the Muyexe magnesite deposit. Furthermore, 62 rock samples were collected during geological field mapping of which 16 representative samples were selected for further analysis. X-ray fluorescence spectrometry was conducted on all selected samples of magnesite and rocks. XRD analysis was conducted on 12 rocks and 2 magnesite samples. Mineralogy of the rocks was also confirmed using petrographic microscopy. Detailed geological map of the Muyexe area revealed that the area is dominated by metamorphic ultramafic and mafic rocks. Basalt and peridotite are intrusions within the rock. The serpentinites and peridotites were found to be the source rock for magnesite mineralization, while the peridotite is the source rock for serpentinites rocks. XRD analysis revealed that magnesite in the Muyexe magnesite deposit is associated with silica and dolomite, while XRF data revealed that the following major oxides are present in magnesite as impurities; silicon dioxide (SiO2), calcium oxide (CaO), and iron oxide (Fe2O3). These oxides reduce the quality of magnesite, thus, their removal is necessary during processing. Magnesite of this deposit was found to be of good quality, with an average value of 54.02 wt. %. Magnesite at Muyexe was formed due to precipitation of Mg2+ along the fractures of serpentinites and peridotites due to CO2rich hydrothermal fluids. Magnesite occurs as a cryptocrystalline of the Kraubathtype. / NRF

A major problem associated with any power generation process in which coal is burned is the formation of ash and slag from the inorganic constituents of the coal. Ash deposition on heat transfer surfaces in coal-fired reactors is unavoidable and can have a significant effect on the performance and maintenance of boilers and gasifiers. A greater understanding of the thermal properties of coal ash deposits is important in reducing their negative impact. This work presents the development of an experimental method for making in situ measurements of the spectral emittance of coal ash deposits. It also provides measured emittances for two coals under oxidizing and reducing conditions. The experimental procedure consisted of burning coal in a down-fired entrained-flow reactor and collecting ash deposits on a circular probe under controlled conditions. Spectra collected from a Fourier transform infrared (FTIR) spectrometer were combined with an instrument response function to measure the spectral emissive power from the surface of the ash deposit. The spectral emissive power was used to infer the deposit surface temperature. These two measurements were used to calculate the spectral emittance of the deposit. This experimental method was validated by measuring the known temperature and spectral emittance of a blackbody radiator. The experimental method was used to find the spectral emittance of bituminous and subbituminous coals under both oxidizing and reducing conditions. The bituminous coal analyzed was Illinois #6 coal from the Crown III mine and the subbituminous coal analyzed was Wyoming coal from the Corederro mine. The spectral emittance of the subbituminous coal was lower than that of the bituminous coal under both oxidizing and reducing conditions. The emittances of both coals under reducing conditions were greater than those found under oxidizing conditions. A total band emittance was defined and calculated for each coal. The total band emittance as well as theoretical upper and lower total emittance limits were calculated as functions of temperature. There was little temperature dependence in the total emittance estimates.

<p> This investigation is intended to explore and trace the trend in the development of muskeg (organic terrain), of which water is an essential factor. The work proceeded as follows: field work and laboratory pollen macerations, identification of pollen and spores and pollen counting; and finally the analysis of the results obtained. </p> <p> The results do not favour the establishment of a strong relationship between water in muskeg and vegetation in situ. However, this needs further test. On the other hand, there are relationships found between pollen species, and also interesting natural grouping was observed to exist in the bogs studied, due to unknown factors. </p> / Thesis / Master of Science (MSc)

No description available.

No description available.

The role of structure and tectonics in the formation of hydrothermal ore deposits and the localization of high-grade mineralization associated with fractures is well documented. In this study we have characterized the structural setting associated with uranium mineralization in the Coles Hill uranium deposit by relating the observed metamorphic and structural features (mylonitic foliation and fractures) to regional tectonic activity. Drill cores and outcrops observed in this study show that NE/SW oriented fractures appear to be related to Mesozoic movement along the Chatham Fault. NW/SE oriented fractures cross cut and offset the NE/SW oriented fractures by1 to 2 cm and therefore post-date the NE/SW oriented fractures. NW/SE fracture orientations and parallel to the NW/SE regional cross faults and are suggested to relate to the formation of the cross faults during post Triassic basin inversion. Uranium mineralization is located within horizontal to shallowly dipping fractures suggesting uplift and erosion to form possible tension veins. The cross faults with NW/SE orientations created pathways in which uranium bearing hydrothermal fluids could migrate from the Triassic basin shales westward into the adjacent highly fractured crystalline rocks, precipitating uranium due to oxidation-reduction reactions. / Master of Science

Topic of this diploma thesis is "The legal protection of the exclusive deposit". Attention in the opening chapters is paid to general issues of mining law. Those general issues include history of mining law, sources of legal regulation and basic concepts. Protection tools of exclusive deposit are also included as a general issue. Those tools are divided in groups as conceptual, administrative and legal and economic tools. The thesis then introduces the most important special protection tools of exclusive deposit used at the various stages of its exploitation. Institute called Exploration area ensures protection of exclusive deposit in stage of searching and exploring. Next special protection tool is Protected deposit area, which is an important instrument of territorial protection of the exclusive deposit. This institute prevents complications with mining caused by construction activities. The following chapter presents the institute of Mining area. Function of Mining area is to protect an exclusive deposit, but it also represents authorization to carry out mining activities. Protection of exclusive deposit is ensured by set of rules, which have to be followed when mining. A separate chapter is devoted to the protection of the exclusive deposit while placing buildings. This issue is situated in...

by Chan Wai-yip, Wong Wai-kwan. / Abstract also in Chinese / Bibliography: leaves 92-93 / Thesis (M.B.A.)--Chinese University of Hong Kong, 1983

by Lau Chung-Hing. / Thesis (M.B.A.)--Chinese University of Hong Kong, 1988. / Includes bibliographical references.