>Magister Scientiae - MSc / Clay diagenesis phenomenon and their effects on some petrophysical properties of lower cretaceous silliciclastic sandstones, offshore Orange basin have been established. Previous studies on Orange basin revealed that chlorite and quartz cements have significantly compromised the reservoir quality in this basin but it is expected that the reservoirs shows better improvement basinward, an analogy of this is displayed by tertiary sandstones deposit, offshore Angola. The main goal of this thesis is to perform reservoir quality evaluation by intergrating geological, geochemical and geophysical tools to substantiate the effects of clay minerals distribution and its subsequent diagenesis on the intrinsic properties (porosity, permeability and saturation) of reservoir intervals encountered within three wells in block 3A (deeper waters), offshore Orange basin. Five lithofacies were identified based on detailed core description from wells KF-1, KH-1 and AU-1 in this block. The facies were grouped based on colour and grain sizes, they are named : A1 (shale), A2 (sandstone), A3 (siltstone), A4 (dark coloured sandstone) and A5 (conglomerates).Depositional environment is predominantly marine, specifically, marine delta front detached bars and deepwater turbiditic sandstone deposit. Geophysical wire line logs of gamma ray, resistivity logs combo and porosity logs were interpreted, parameters and properties such as VCL, porosity, permeability and saturation were estimated from these logs and the values obtained were compared with values from conventional core analysis data, the values agreed well with each other. Detailed petrographic studies (SEM, XRD and thinsection) plus geochemical studies (CEC, EDS, pH, Ec) were carried out on twenty two core samples to establish if these clay minerals and other cements have pervasive effects on the reservoir quality or otherwise.

The objective of this review is to summarise the characteristics, significance and evolution of heavy minerals and their accumulations, and to identify the key controls on the development and distribution of heavy mineral concentrations in alluvial systems. These controls can be broadly classified as tectonic setting, geomorphic setting and grain-scale concentrating processes, each of which is discussed. Based on this review, exploration models are developed which are designed to indicate favourable localities for the accumulation of heavy minerals, and trends likely to be exhibited within these accumulations. The models are structured from the broadest scale of target selection, down to the local scale of sample site selection. The major conclusion of this work is that an understanding of process geomorphology is required to develop genetic models of placer development, including a detailed evaluation of climatic fluctuations throughout the Caenozoic. Palaeoplacers such as the Witwatersrand goldfield, are inferred to have formed under similar circumstances of tectonic setting as genetically comparable Caenozoic placers such as those of Otago, New Zealand. The means of preservation of such major basins is however poorly understood.

A number of ilmenite-rich heavy mineral deposits occur along the northern margin of the intracratonic Karoo basin, and are hosted by the fluvio-deltaic Middle Ecca Group. Coastal reworking of delta front sands within a regressive, microtidal shoreline may be considered as a depositional model for the development of the heavy mineral deposits. An economic analysis of titanium suggests long term positive demand, and sustained high prices for this commodity. An evaluation of the Dwarsfontein ilmenite-rich heavy mineral deposit, using available data, indicates how important it is for deposits of this type to be situated close to an upgrading plant or export harbour.

The fundamental cause of low temperature breakdown (reduction disintegration) is reduction of hematite to magnetite, resulting in a volume expansion and stress relief through the formation of cracks. Serious reduction disintegration causes poor gas permeability, high flue dust production and scaffolding, poor gas distribution, higher fuel consumption and lower productivity. Northern Cape iron ore generally performs well when tested for reduction disintegration properties both for blast furnaces and Corex; nevertheless, significant breakdown is experienced when used in the Corex process (at Saldanha Steel). This study was hence conducted to determine the effects of the following on reduction disintegration:<ul><li> different ore types (from Northern Cape) </li> <li> initial particle size</li><li> temperature range</li><li> reduction gas composition</li></ul> Although disintegration is clearly triggered by reduction, no direct correlation could be established between the percentage reduction and the percentage fines generated. The results indicated that the presence of gangue minerals alone does not cause fractures to form, but does influence the direction and intensity of fractures to some extent. In many cases cracks form randomly, with no specific preference for either gangue minerals or iron oxides. For most of the samples, an incubation period was observed before the first cracks formed. No crack propagation was observed after initial cracking. This study indicates that the degree of reduction disintegration depends mostly on furnace conditions. Reduction disintegration increased with higher hydrogen percentages (>5%), higher temperatures (in the 500ºC-700ºC range) and longer exposure. Disintegration of the samples decreased at temperatures higher than 750°C. For particles smaller than 16 mm an inverse relationship was found between the average particle size and the percentage of fines generated, in line with the observation that most of the disintegration is due to spalling from particle edges rather than particles breaking into smaller clumps. The results indicate that it is important to manage the temperature in the top of the blast furnace and the COREX shaft, and the time spent at temperatures below 750°C, to minimize the amount of fines generated. / Thesis (PhD)--University of Pretoria, 2010. / Materials Science and Metallurgical Engineering / unrestricted

The Mt. Milligan deposit is a tilted (~45°) Cu-Au alkalic porphyry located 155 km northwest of Prince George, B.C., Canada. It is the youngest of the BC alkalic porphyry deposits, all of which formed between 210 to 180 Ma in an extensive belt of K-enriched rocks related to the accretion of the Quesnellia-Stikinia superterrane to ancestral North America. Mt. Milligan has a measured and indicated resource of 205.9 million tonnes at 0.60 g/t Au and 0.25% Cu containing 3.7 million oz. gold, and 1.12 billion lb. copper. Shoshonitic volcanic and volcaniclastic andesites host mineralization. These have been intruded by a composite monzonitic stock (MBX stock), and associated sill (Rainbow Dike). Early disseminated chalcopyrite-magnetite and accessory quartz veins are associated with K-feldspar alteration in the MBX stock. A halo of biotite alteration with less extensive magnetite replaces host rocks within a ~150 m zone surrounding the stock, while K-feldpsar alteration extends along the Rainbow Dike and permeable epiclastic horizons. Peripheral albite-actinolite-epidote assemblages surround the K-silicate zone. Albite-actinolite occurs at depth, and epidote dominates laterally. Copper and Au grade are maximal where the albite-actinolite assemblage overprints biotite alteration. Gold grade is moderate in association with epidote, whereas Cu is depleted. The post-mineral Rainbow Fault separates the core Cu-rich zone from a downthrown Au-rich zone. A similar zonation of metals occurs in the hanging-wall (66 zone), where a Cu-bearing, potassically-altered trachytic horizon transitions to a funnel-shaped zone of pyrite-dolomite-sericite-chlorite alteration with elevated gold. Sulfide S-isotope compositions range from -4.79 δ34S in the central Cu-Au orebody to near-zero values at the system periphery, typical of alkalic porphyries. Sulfur isotope contours reflect the magmatic-hydrothermal fluid evolution, and indicate late-stage ingress of peripheral fluids into the Cu-Au zone. Carbonate C- and O-isotope compositions corroborate the magmatic fluid path from the Cu-Au rich zone to Au-rich zone with decreasing depth. Strontium isotopic compositions of peripheral alteration minerals indicate a laterally increasing meteoric fluid component. Changes in major- and trace element composition of epidote and pyrite across the deposit are also systematic. These provide additional vectors to ore, and confirm the kinematics of the Rainbow Fault. / Science, Faculty of / Earth, Ocean and Atmospheric Sciences, Department of / Graduate

The eastern Democratic Republic of Congo has experienced constant instability and conflict since 1996. With the collapse of the state of Zaire and the renaming of the country by the late Laurent Desire Kabila in late 1996, there were high expectations from the Congolese population that the country was going to move forward. However, in less than two years, the central government in Kinshasa was facing a new rebellion from the east of the country, followed by widespread violence and criminal activities by armed and militia groups. Although military intervention from Zimbabwe, Namibia and Angola halted the rebellion march to Kinshasa, the capital city of DRC, and allowed the DRC government to sign peace agreement with its opponents in 2002; since then, the prospect of peace in the eastern DRC, especially the North and South Kivus seems bleak. Since 2002, that region has been the theatre of armed and militia groups (both local and foreign), owing to, in the views of various experts, the presence of mineral resources to support their criminal activities, as well as the economic interests of regional actors to create proxy militia and armed groups in the absence of central government in much of eastern DRC. The purpose and rationale of this study is to critically identify actors in the postconflict reconstruction process, and examine the role of mineral resources among other perpetuating factors of the protracted conflict in eastern DRC, in order to arrive at a comprehensive analysis of the reasons for the failure of peace building and post-conflict reconstruction processes that have been undertaken. This study aims to fill a gap in available literature, by pointing to some conflict drivers and factors which have previously been overlooked in post-conflict reconstruction, and in existing research on the topic, especially the role of mineral resources in sustaining conflict. A thorough conceptualization of relevant conflict theory and a historical overview of the conflict in DRC were provided as a point of departure in order to understand other factors that contribute to the intractability of conflict in eastern DRC, this study found that those factors were rooted in the legacy of colonialism; the bad leadership under both the colonial powers and subsequent government of Joseph Mobutu, manipulation and politicization of ethnic identities especially in the South and North Kivu and the geopolitical location of the eastern DRC. This study further established that the presence of mineral resources in eastern DRC indeed contributes to the continued insecurity in that region by providing succour to armed groups, thus undermining peace agreements especially the Pretoria agreement that formally ended hostilities in 2002. Furthermore, the study found that the issue of mineral resources is not the sole driver of the eastern DRC conflict, as the issues of ethnic polarisation especially, discrimination against Kinyarwanda speaking Congolese in the east, and the view that only military means can solve this problem; coupled with other security threats including the presence of foreign militia groups motivate the neighbouring countries of Uganda, Rwanda and Burundi to constantly meddle in DRC's internal affairs. The study suggests that additional research be conducted to further investigate the regional dimensions of the conflict and how perceived interests in mineral revenue contribute to the polarisation of the population in eastern DRC; leading to the proliferation of armed groups.

Orientador: Kléber Tomás de Resende / Banca: Marcos Jácome de Araújo / Banca: Izabelle Auxiliadora Molina de Almeida / Resumo: Objetivou-se determinar as exigências de Ca, P, Mg, K e Na em machos inteiros, machos castrados e fêmeas da raça Saanen. Foram realizados dois experimentos: um para determinar as exigências líquidas para mantença (Exp. 1) e outro para determinar as exigências líquidas para crescimento (Exp. 2). Setenta e cinco caprinos (26 machos inteiros, 25 machos castrados e 24 fêmeas) foram utilizados para determinar as exigências líquidas para mantença. Desses, 21 caprinos (8 machos inteiros, 7 machos castrados e 6 fêmeas) foram abatidos com peso médio de 16,6 ± 0,40 kg e foram utilizados como grupo referência para estimar a composição corporal inicial. Os 54 caprinos restantes (18 machos inteiros, 18 machos castrados e 18 fêmeas) foram alocados em seis blocos ao acaso, no quais foram incluídos três caprinos do mesmo sexo distribuídos em um dos três níveis de alimentação: ad libitum e ingestão de 75% ou 50% em relação aos animais alimentados ad libitum. Quando os animais alimentados ad libitum atingiram 30 kg de PC foram abatidos juntamente com os outros caprinos do mesmo grupo. Os dados das categorias sexuais e dos níveis de alimentação foram analisados em parcelas subdivididas. A parcela principal foi composta pelas três categorias sexuais e as subparcelas pelos três níveis de alimentação. Os requerimentos líquidos para mantença não diferiram entre as categorias sexuais (P > 0.05), resultando em valores de: 35,4 mg de Ca; 24,7 mg de P; 2,5 mg de Mg; 5,0 mg de K e 3,3 mg de Na/kg PC·d. ... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Our study estimated Ca, P, Mg, K, and Na requirements of intact male, castrated male, and female Saanen goats. Two experiments were performed: one to determine the net macromineral requirements for maintenance (Exp. 1), and another to determine net macromineral requirements for growth (Exp. 2). In Exp. 1, 75 goats (26 intact males, 25 castrated males, and 24 females) with initial BW (iBW) of 15.76 ± 0.10 kg were used. These animals were divided in two groups: baseline animals and pair-fed animals. Twenty-one goats (8 intact males, 7 castrated males, and 6 females) were slaughtered at the beginning of the experiment (16.6 ± 0.40 kg BW) to be used as the baseline group. The 54 remaining goats (18 intact males, 18 castrated males, and 18 females) were pair-fed in 6 blocks of 3 goats per sex. The goats within each block were then randomly allocated to one of 3 different levels of intake: ad libitum, restricted-fed to 75% of the ad libitum intake, and restricted-fed to 50% of ad libitum intake. When the animal fed ad libitum reached 31.2 ± 0.58 kg BW, it and the other goats from the same block were slaughtered. The effects of sex and level of intake were evaluated in a split-plot design, where sex was the main plot observation and level of intake was the sub-plot. Daily net macromineral requirements for maintenance did not differ among the sexes (P > 0.05), and the average values obtained were 35.4 mg Ca, 24.7 mg P, 2.5 mg Mg, 5.0 mg K, and 3.30 mg Na per kg BW. The net requiremen... (Complete abstract click electronic access below) / Mestre

Edible insects have been part of the diet of many countries across the world for several decades. It is becoming increasingly popular in the europian developed countries, mainly because of the content of nutritionally important substances. The theoretical part of the thesis deals with the characterization of edible insects in terms of nutritional benefits, explains the reasons and method of breeding edible insects. For the analysis of nutritionally active substances, flour of house cricket (Acheta domesticus) was used. A. domesticus belongs to the representatives of insects legalized from 1.1. 2018 on the EU market. Of the significantly nutritional substances, proteins, lipids, fatty acids, fiber and selected minerals were analyzed. In this study, optimalization of vertical electrophoresis SDS-PAGE was performed to determine protein fragment sizes. In the second part the influence of acricket flour addition protein bars was investigated by sensory analysis. In the experimental part that was found that cricket flour contains protein, lipids and fatty acids in significant amounts. It also contains important minerals for human health such as magnesium, potassium, iron or zinc. However, the sensory properties of protein bars for consumers were not very attractive.

Do the peculiar ion concentrations of serpentine soils appear in the tissues of plants growing on those soils? To what extent are the same species of plants growing in serpentine and non-serpentine soil similar in ionic concentrations? This work was an attempt to answer these questions.

Orientador: Leonardo Susumu Takahashi / Resumo: Os microminerais possuem papéis importantes no metabolismo animal, participam de funções fisiológicas, crescimento, desenvolvimento e saúde em peixes. O objetivo deste estudo foi avaliar a suplementação da dieta com microminerais orgânicos no desempenho produtivo e qualidade do filé de juvenis de tilápia (Oreochromis niloticus). Foram formuladas 3 dietas práticas isoprotéicas e isoenergéticas com três níveis de inclusão (0,0; 1,0 e 1,5%) de um blend de microminerais orgânicos composto por: ferro, zinco, manganês, cobre, selênio e cromo. Foram realizados dois experimentos distintos, um com alimentação durante período pré-abate (7 dias) e outro, durante período longo de alimentação (30 dias). Em cada um dos experimentos, foram utilizados 120 juvenis em fase de terminação com peso médio de 360,6 g, distribuídos aleatoriamente em 12 caixas de 1000 L em um sistema de circulação fechado. Foram avaliados parâmetros da qualidade do filé no período pré-abate (7 dias): potencial hidrogeniônico (pH), rendimento de filé, cor, perdas de peso cozimento (cooking loss), perdas de peso por descongelamento (drip loss) e capacidade de retenção de água (CRA). As análises no após período de 30 dias de alimentação, foram as mesmas do período pré-abate com adição de: parâmetros de desempenho produtivo (ganho de peso, conversão alimentar e taxa de crescimento específico), textura do filé, oxidação lipídica (TBARS), concentração de bases voláteis totais (BVT), concentração de nitrogênio não protéico ... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Microminerals play important roles in animal metabolism participate in physiological functions, growth, development and health in fish. The aim of this study was to evaluate the dietary supplementation with organic microminerals in the productive performance and quality of the tilapia (Oreochromis niloticus) juvenile fillet. A 120 juveniles were used in the finishing phase with an average weight of 360.6 g, randomly distributed in 12 boxes of 1000 L in a closed circulation system. 3 practical isoproteic and isoenergetic diets were formulated with three levels of inclusion (0.0, 1.0 and 1.5%) of a blend of organic minerals composed of: iron, zinc, manganese, copper, selenium and chromium.Two different experiments were carried out, one with feeding during the pre-slaughter period (7 days) and the other, during a long feeding period (30 days). In each of the experiments, 120 juveniles were used in the finishing phase with an average weight of 360.6 g, randomly distributed in 12 boxes of 1000 L in a closed circulation system. Parameters of fillet quality in the pre-slaughter period (7 days) were evaluated: hydrogen potential (pH), fillet yield, color, cooking loss, weight loss by defrosting (drip loss) and retention capacity of water (CRA). The analyzes in the period after 30 days of feeding were the same as in the pre-slaughter period with the addition of: production performance parameters (weight gain, feed conversion and specific growth rate), fillet texture, lipid oxidation (... (Complete abstract click electronic access below) / Mestre