The Kansanshi Cu-Au deposit, Domes region, Zambia : geology, mineralisation and alteration characteristics in the main pit
- Authors: Chinyuku, Donald Tichaona
- Date: 2014
- Subjects: Kansanshi Mine -- Zambia , Copper mines and mining -- Zambia , Gold mines and mining -- Zambia , Gold -- Assaying -- Zambia , Geology -- Zambia , Mineralogy -- Zambia , Tillite
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5051 , http://hdl.handle.net/10962/d1011758 , Kansanshi Mine -- Zambia , Copper mines and mining -- Zambia , Gold mines and mining -- Zambia , Gold -- Assaying -- Zambia , Geology -- Zambia , Mineralogy -- Zambia , Tillite
- Description: The Kansanshi Cu-Au deposit located in the Domes region of the North West province of Zambia is characterised by structurally controlled high angle veins and associated alteration halos. The northwest trending Kansanshi antiform flanks the Solwezi syncline to the north and hosts the Kansanshi deposit and consists of tillites and metasedimentary rocks. Mineralisation is associated with Neoproterozoic Pan African deformation events experienced during the formation of the Lufilian fold belt; however recent findings confirm that structures in the form of reverse and normal faults and drag folds are critical controls on mineralisation within the deposit, Main pit in particular. Low angle faults occurring below the current pit are believed to have served as major fluid pathways during mineralisation. Age dating data from the Kansanshi deposit suggest that mineralisation took place between 512 and 503 Ma indicating that the event was associated with metamorphism. Two types of alteration are dominant within the Main pit (Kansanshi deposit) with the type and intensity of alteration being largely controlled by lithological units. Albite alteration occurs dominantly in phyllites and schists whereas dolomitisation is prevalent in calcareous units. Alteration is associated with mineralisation, and therefore is used as a condition for predicting vein or disseminated mineralisation. The high Au tenor at Kansanshi can be attributed to gold grains occurring in association with melonite (NiTe₂) and microfractured pyrite intergrown with chalcopyrite in sulphide and quartz dominated veins and veinlets. Analysis of gold grade distribution within the Main pit shows a clear concentration of the element along the major north-south trending structures like the 4800 and 5400 zones, possibly through supergene enrichment in the oxide-transition-sulphide zones. It is imperative that exploration for Kansanshi-type deposits will require geochemical and geophysical studies, understanding of the geology of an area to identify the three lithostratigraphic units (red beds, evaporites and reducing strata).
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- Date Issued: 2014
Substituted phthalocyanines development and self-assembled monolayer sensor studies
- Authors: Matemadombo, Fungisai
- Date: 2006
- Subjects: Phthalocyanines , Monomolecular films , Electrochemistry , Spectrum analysis
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4364 , http://hdl.handle.net/10962/d1005029 , Phthalocyanines , Monomolecular films , Electrochemistry , Spectrum analysis
- Description: Zinc, cobalt and iron phenylthio substituted phthalocyanines have been synthesized and characterized. Cyclic and square wave voltammetry in dimethylformamide containing tetrabutylammonium perchlorate revealed five and six redox processes respectively for the cobalt and iron phenylthio substituted phthalocyanines. These complexes are easier to reduce compared to the corresponding unsubstituted MPc and to butylthio substituted derivatives. Spectroelectrochemistry (in dimethylformamide containing tetrabutylammonium perchlorate) was employed to assign the cyclic voltammetry peaks, and gave spectra characteristic of Fe(I)Pc for reduction of iron phenylthio substituted phthalocyanine and Co(I)Pc for the reduction of cobalt phenylthio substituted phthalocyanine. The spectrum of the former is particularly of importance since such species have not received much attention in literature. Cobalt and iron phenylthio substituted phthalocyanines have been deposited on Au electrode surfaces through the self assembled monolayer (SAM) technique. The so formed layers were studied using voltammetric techniques. These SAMs blocked a number of Faradic processes and electrocatalyzed the oxidation of L-cysteine. Amine substituted cobalt phthalocyanine (CoTAPc) was deposited on gold surfaces by using an interconnecting SAM of mercaptopropionic acid or dithiobis(N-succinimidyl propionate) through the creation of an amide. Reductive and oxidative desorption of the SAMs limit the useful potential window. The SAM-CoTAPc layers show electrocatalytic activities towards oxygen reduction through the Co(I) central metal ion. Both SAMs were highly stable and hence will be interesting tools for further research in surface modification and sensor development.
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- Date Issued: 2006
Marine biotechnology : evaluation and development of methods for the discovery of natural products from fungi
- Authors: Pather, Simisha
- Date: 2005 , 2013-06-18
- Subjects: Marine biotechnology , Marine fungi -- South Africa , Natural products -- South Africa , Marine plants -- South Africa , Marine metabolites -- South Africa , Cancer -- Treatment , DNA
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3839 , http://hdl.handle.net/10962/d1007652 , Marine biotechnology , Marine fungi -- South Africa , Natural products -- South Africa , Marine plants -- South Africa , Marine metabolites -- South Africa , Cancer -- Treatment , DNA
- Description: One of the major impediments in the development of marine natural products is the provision of biologically active natural products in sufficient quantity for complete pharmacological evaluation, clinical trials and eventual commercial production. Marine microorganisms show great promise in providing a renewable source of biologically active natural products. The main aim of this study was to develop and evaluate methods for the isolation, identification and cultivation of marine fungi from the South African marine environment for the production of biologically active secondary metabolites. Twenty-four species of fungi were isolated from marine algae collected from the intertidal zone near Port Alfred, South Africa. The fungi were cultivated in small-scale under static and agitated conditions and their crude intra- and extracellular organic extracts were screened by ¹H NMR and a series of bioassays. Using this as a basis, one isolate was selected for further study. By analyses of the lTS1 region of the ribosomal DNA, the fungal isolate was identified as a marine-derived isolate of Eurotium rubrum (Aspergillus ruber). Although E. rubrum has been isolated from the marine environment, no investigations have been undertaken to determine the adaptation of these isolates to the marine environment. In order to optimise productivity, creativity and incubation time, the fungus was cultivated in small-scale using a variety of carbon (glucose, fructose, lactose, sucrose, marmitol and maltose) and nitrogen sources (ammonium tartrate, urea, peptone and yeast extract). An HPLC-DAD method was developed to assess the metabolic creativity and productivity under different fermentation conditions. Distinctive variations in the range and yield of metabolites produced as well as morphology and growth time were observed. The crude extracts from all fermentations were combined and six known compounds were isolated by reversed-phase chromatography and their structures elucidated by spectroscopic techniques. The known compounds were fIavoglaucin, aspergin, isodihydroauroglaucin, isotetrahydroauroglaucin, neoechinuline A and physcion. Neoechinuline A, isodihydroauroglaucin and isotetrahydroauroglaucin showed activity against oesophageal and cervical cancer cell lines.
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- Date Issued: 2005
A review of the Kalahari group: an aid to Kimberlite exploration in this medium
- Authors: Williams, Clint
- Date: 2003 , 2013-05-23
- Subjects: Kimberlite -- Kalahari Desert , Sedimentation and deposition -- Kalahari Desert
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4916 , http://hdl.handle.net/10962/d1003216 , Kimberlite -- Kalahari Desert , Sedimentation and deposition -- Kalahari Desert
- Description: The Kalahari Group sediments cover vast portions of the Archean Kaapvaal and Congo cratons that are considered highly prospective for economic kimberlites. In southern Africa, the term Kalahari refers to a structural basin, a group of Cretaceous to recent terrestrial continental sediments and an ill-defined desert, all of which have been grouped together as the Mega Kalahari by Thomas and Shaw (1993). The Mega Kalahari grouping includes sediments stretching from South Africa in the south to the Democratic Republic of Congo in the north, and from eastern Namibia to western Zimbabwe. This sand sea, at 2.5 million km², is the largest on earth and presents significant obstacles and challenges to the kimberlite explorationist attempting to locate bedrock-hosted diamondiferous kimberlite bodies. The Mega Kalahari sediments represent an ancient depositional environment with a complex history in which the stratigraphy and age of the deposits are not particularly well constrained or understood. Low fossil content, limited exposure, poor differentiation of the dominant surficial Kalahari Sand and a limited comprehension of an extensive duricrust suite has delayed the understanding of the sedimentological and environmental history of the basin. This sequence of sediments has accumulated and evolved through fluvio-deltaic, aeolian and groundwater processes, with characteristics due to primary deposition and subsequent modification being difficult to distinguish. Deposition in the Kalahari Basin has been subject to tectonic influences, changes in drainage directions and source areas of sediments, river capture and numerous large and small climatic fluctuations both in the basin and surrounding areas. It bears the imprint of recurring cycles during which the same sediments were reworked, sometimes by different agencies, all of which exacerbate attempts to correlate sedimentary units across the sequence. The Mega Kalahari is a series of contiguous Phanerozoic sedimentary basins situated within the African Superswell. The Superswell has dominated the gross geomorphology of southern Africa and contributed significantly to the present character of the Mega Kalahari and the evolution of the drainage systems. Overall, the tectonic framework established in southern Africa by the division of Gondwanaland led to the creation of a dual drainage system, with the hingeline acting as a watershed between a coastally-orientated exoreic system and an endoreic system draining into the interior. Deposition of sediments started in the late Cretaceous. Neo-tectonic activity expressed in the rifting in central Botswana, further influenced sedimentation rates and exerted a strong control over paleo-drainage directions. This revIew presents the complexities of the Kalahari cover sequence. The most Important geomorphological and sedimentary factors to be considered when designing and implementing kimberlite exploration programs within the Mega Kalahari environment are outlined and discussed. New data from exploration drilling programs are presented on the thickness of the Kalahari within portions of northern Namibia, western Zambia and Botswana. , KMBT_363 , Adobe Acrobat 9.54 Paper Capture Plug-in
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- Date Issued: 2003
The structure and function of the gametes of the striped field mouse (Rhabdomys pumilio)
- Authors: Tinney, Gregory Michael
- Date: 2000
- Subjects: Gametes , Microtus , Mice
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5774 , http://hdl.handle.net/10962/d1005462 , Gametes , Microtus , Mice
- Description: This study was initiated in an attempt toadd the four-striped field mouse (Rhabdomys pumilio) to the small group of mammals that are used to study and develop assisted reproductive technologies. To accomplish this, a complete knowledge of both the male and female gametes was necessary, as well as a repeatable and successful IVF protocol. The gametes of the field mouse, both the falciformspermand the mature oocytes, were shown to be similar in several respects to those of many other rodent species. The induction of both the capacitated state and the acrosome reaction in the sperm were readily achieved. The success of retrieving mature oocytes was very low, with the rare occurrence of polar bodies within ovulated oocytes. The difficulties with oocytes was either related to the lack of a regular oestrous cycle, or to the hormonal regime used to induce superovulation. Although several protocols were used to accomplish superovulation in this species, it was seldom achieved. In in vitro fertilization trials, sperm were found to attach to both the cumulus oophorus and the zona pellucida of the oocytes. However, fertilization was never accomplished. This failure to achieve fertilization was probably related to the immaturity of the oocytes. Without further studies on Rhabdomys pumilio and further attempts at accomplishing in vitro fertilization, it would seem that this species would not easily be introduced as an animalmodelfor assisted reproduction.
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- Date Issued: 2000
The diet of the black-backed jackal (Canis mesomelas) and caracal (Felis caracal) in the Eastern Cape, South Africa
- Authors: Bussiahn, Frans Ernst Carl
- Date: 1998
- Subjects: Black-backed jackal -- South Africa -- Eastern Cape , Felis -- South Africa -- Eastern Cape , Jackals -- South Africa -- Eastern Cape , Jackals -- Food , Felis -- Food
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5807 , http://hdl.handle.net/10962/d1006489 , Black-backed jackal -- South Africa -- Eastern Cape , Felis -- South Africa -- Eastern Cape , Jackals -- South Africa -- Eastern Cape , Jackals -- Food , Felis -- Food
- Description: The black-backed jackal (Canis mesomelas) and the caracal (Felis caracal) are considered by most farmers in the Eastern Cape to be responsible for excessive livestock losses (sheep and goats) and are, as such, hunted extensively within the Province. Stomach content analyses of individuals killed during predator control operations indicate that caracal are opportunistic hunters of small to medium-sized mammals, preying predominantly on antelope within farmland. Black-backed jackal are opportunistic omnivores, preying predominantly on livestock and antelope in farmland, while invertebrates and antelope constitute the major food items within a game reserve. The diet of caracal was found to be largely influenced by the age of individual animals with old and young animals being the predominant killers of livestock, whereas black-backed jackal diet is influenced primarily by the social structure exhibited by the species, with male animals exhibiting a marked summer peak in livestock killing, due to the increased energetic demands of parental care associated with a long term pair bond. Two caracal (a sub-adult male and adult female), were radio-tracked within farmland for a total of twelve months, yielding the smallest recorded homerange sizes for the species to date (2.1km² and 1.3km² respectively). No livestock losses were recorded within these homeranges for the duration of the study. These data suggest a relatively high abundance of caracal within Lower Albany and further illustrate that individual animals are capable of preying solely on natural prey species over an extended period, when occurring within livestock farming areas. The analysis of local hunt club records and questionnaires revealed a higher incidence of local black-backed jackal (15.2 PD/Kill), than caracal (34.7 PD/Kill), with a marked seasonal peak in kills, for both species, occurring during summer months. The use of hound packs was found to be more effective in reducing the overall abundance of caracal than black-backed jackal, as this technique was seen to eliminate more adult female caracal than black-backed jackal, during the respective breeding season of each species. Local hunt club owners and farmers were more accurate in identifying problem black-backed jackal (74%), than caracal (59%). Recommendations are presented for minimizing stock losses through the application of selective control of specific problem animals, the use of various control measures and encouraging natural prey abundance.
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- Date Issued: 1998
A study of real-time operating systems for microcomputers
- Authors: Wells, George Clifford
- Date: 1990
- Subjects: Operating systems (Computers) , Microcomputers
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4611 , http://hdl.handle.net/10962/d1004896 , Operating systems (Computers) , Microcomputers
- Description: This thesis describes the evaluation of four operating systems for microcomputers. The emphasis of the study is on the suitability of the operating systems for use in real-time applications, such as process control. The evaluation was performed in two sections. The first section was a quantitative assessment of the performance of the real-time features of the operating system. This was performed using benchmarks. The criteria for the benchmarks and their design are discussed. The second section was a qualitative assessment of the suitability of the operating systems for the development and implementation of real-time systems. This was assessed through the implementation of a small simulation of a manufacturing process and its associated control system. The simulation was designed using the Ward and Mellor real-time design method which was extended to handle the special case of a real-time simulation. The operating systems which were selected for the study covered a spectrum from general purpose operating systems to small, specialised real-time operating systems. From the quantitative assessment it emerged that QNX (from Quantum Software Systems) had the best overall performance. Qualitatively, UNIX was found to offer the best system development environment, but it does not have the performance and the characteristics required for real-time applications. This suggests that versions of UNIX that are adapted for real-time applications are worth careful consideration for use both as development systems and implementation systems.
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- Date Issued: 1990
The geology and alteration/mineralization of the Van Rooi's vley W/Sn deposit, Namaqua metamorphic complex, South Africa
- Authors: Smithies, Robert Hugh
- Date: 1987 , 2013-03-01
- Subjects: Mineralogy -- South Africa , Geology -- South Africa -- Namaqualand
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4924 , http://hdl.handle.net/10962/d1004526 , Mineralogy -- South Africa , Geology -- South Africa -- Namaqualand
- Description: Scheelite, wolfram Ite and cassIterIte mIneralizat ion is hosted wIthin numerous quartz-tourmaline-feldspar-fluorite veins at Van Rooi's Vley, N.W. Cape Province . MineralizatIon and hydrothermal alteration within, and around, these veins is hIghly complex and reflects the intricate interaction of hydrotherma l activity upon a structurally deformed sequence of ProterozoIc med ium to high-grade gneisses. Four distinct stages of alteration and mineralization occurred, including a l ate 'epithermal stage'. Although the location of mineralization was strongly controlled by st ructure, the concentration of mineralizati on was controlled by physicochemical variables, of which host-rock geochemistry was particularly important . Further W/Sn mineralization occurs on a local scale, some of which is spatia lly related to minor leucogranite dykes. Leucogranite bodies are not uncommon within the region and some are enriched in Wand Sn. By comparing FIB ra tio s,W/Sn ratios, the alteration mineralogy, the ore mineralogy and the Fe-content of tourmaline, the deposits within the Van Rooi's Vley area can be placed into a 'proximal' to 'distal' classification, with respect to a common source of mineralizing hydrothermal fluids. The Van Rooi's Vley deposit, whilst affiliated to greisen-style deposits, represents a ' distal' quartz-vein lode deposit. , KMBT_363 , Adobe Acrobat 9.53 Paper Capture Plug-in
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- Date Issued: 1987
Sampling in the evaluation of ore deposits
- Authors: Grant, D E C S
- Date: 1981 , 2013-03-19
- Subjects: Ore deposits , Mine valuation , Ores -- Sampling and estimation
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5008 , http://hdl.handle.net/10962/d1005912 , Ore deposits , Mine valuation , Ores -- Sampling and estimation
- Description: Sampling is an error generating process and these errors should be reduced to a minimum if an accurate ore reserve estimation is to be made from the sample values. Error in sampling can arise from the sampling procedure as well as where and how each sample is taken from the deposit . Sampling procedure involves sample collection, sample reduction and analysis, and the error from each of these three stages has an equal influence on the total error of the process. Error due to sampling procedure should be identified and eliminated at an early stage in the evaluation programme. An ore deposit should be subdivided into sampling strata along geological boundaries, and once these boundaries have been established they should be adhered to for the evaluation programme. The sampling of each stratum depends on the small-scale structures in which the grade is distributed, and this distribution in relation to sample size controls sample variance, sample bias and the volume of influence of each sample. Cluster sampling can be used where an impractically large sample is necessary to reduce sample variance or increase the volume of influence of samples. Sample bias can be reduced by composing a large number of small samples . Sampling patterns should be designed with reference to the volumes of influence of samples, and in favourable geology, geostatistical or statistical techniques can be used to predict the precision of an ore reserve estimation 1n terms of the number of samples taken. Different are deposits have different sampling characteristics and problems which can be directly related to the geology of the mineralization. If geology is disregarded when sampling an are deposit, an evaluation programme cannot claim to give an accurate estimate of the ore reserves .
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- Date Issued: 1981
Attempted synthesis of a [beta] or [gamma] resorcinyl alcohol
- Authors: Ryding, William Wallace
- Date: 1952
- Subjects: Alcohol -- Synthesis , Resorcinol
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4517 , http://hdl.handle.net/10962/d1014134
- Description: The ultimate objective of this research is the elucidation of the mechanism of the resorcinol-formaldehyde condensation. Whilst a vast literature has been built up about the phenol- formaldehyde condensation, that of resorcinol has received but scant attention, probably because the high reactivity of resorcinol rendered the following of the condensation extremely difficult. The earliest observation concerning the resorcinol-formaldehyde condensation was due to Baeyer who, in 1872, condensed resorcinol with various aldehydes. When the aldehyde was relatively inactive crystalline compounds were obtalned but with acetaldehyde or formaldehyde a resinous product resulted. In 1892 Caro condensed an excess ot resorcinol with formaldehyde in the presence of dilute hydrochloric acid; the product obtained recrystallised from alcohol as white microsoopic crystals, decomposed without melting at 250° and was stated to be bis (2- 4 dihydroxyphenyl) methane ... In decidlng upon the most suitable lines of attack it would seem that a survey of the literature relating to the phenol-formaldehyde concentration which might be expected to be closely related to that of resorcinol, would be of value. Summary of p. 1-5
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- Date Issued: 1952