Thesis (Ph. D.)--Cornell University, 1905. / Reprinted from Scott geog. mag., vol. XXVII (1911), pp. 417-26; 470-74. Bull. Phil. geog. soc., vol. IX (1911), pp. 1-22. Bull. Amer. geog. soc., vol. XLII (1910), pp. 594-602. Bull. Amer. geog. soc., vol. XLIV (1912), pp. 97-112. Scott geog. mag., vol. XXVI (1910), pp. 449-466. Bull. Phil. geog. soc., vol. X (1912), pp. 36-50. Jour. geog., vol. X (1912), pp. 316-319."

Thesis (M.Eng.)(Geotechnical)--University of Pretoria, 2004. / Includes summary. Includes bibliographical references.

Thesis (M.Eng.(Electrical Engineering))--University of Pretoria, 2000. / Includes abstract in English. Includes bibliographical references.

Thesis (Professional Degree)--University of Missouri, School of Mines and Metallurgy, 1938. / Leaf number 26 was duplicated, constituting leaves number 26 and 26 1/2. The entire thesis text is included in file. Typescript. Title from title screen of thesis/dissertation PDF file (viewed April 27, 2010)

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References appear at the end of each chapter / The importance of gold in the development of South Africa as an industrialised economy cannot be over - emphasised. Towards the end of the 19th century the economy depended almost entirely on the production of gold and diamonds which laid the foundation for a highly - developed national economy. With gold still continuing to play an important role coupled with the recent price increases, a need was felt to investigate the potential effect of higher prices on gold production in South Africa. For reasons set out in the study, it was decided to compare potential out put for five different gold prices. A gold price received by the mines of 050 per ounce was used as abase. Further calculations were made at 060, 070, 0100 and 0150 per ounce. The calculations for all the cases were done duri ng the period when the Rand was floating with the Pound Sterling and a Rand : Dollar parity of 1:1, 2 4 was used. Since then two parity changes occured : the Rand was pegged to the Dollar on the 25th October, 1972 to give a Rand : Dollar parity of 1:1,27732, and the Dollar was devalued on the 13th February, 1973 by 1 1,1 % to give the present Rand : Dollar parity of 1:1, 4192. The e ffect of the above two parity changes is that revenue in Dollar terms is overstated by 14,45 5%. It is suggested that for purposes of this study the Rand figures be accepted and wherever Dollars are used in future estimates these be increased by the afore-mentioned 14, 455%. In Dollar terms the five Cases analised will change as follows: Case A : 5350 becomes 057, 23 per ounce Case B : 260 becomes 068, 67 per ounce Case C : 270 becomes 080,12 per ounce Case D : 0100 becomes 0114 ,46 per ounce Case E : 0150 becomes 0171, 68 per ounce To do an in-depth investigation into the effects of higher gold prices on each individual mine, it was necessary to analyse the various parameters required in the determination of gold p r oduction, revenue, lease and tax payments , and dividends. For each mine the pay limits at the various gold prices and at estimated working cost levels, were determined . Graphs of the estimated tonnages at various pay limits as well as the average grade of ore mineable at these limits were determined. From these graphs it is possible to obtain the total tonnage mi neable at various pay limits. Once the foregoing parameters were obtained for each mine, it was possible to determine annual gold production, revenue, lease and tax payments and amounts available to share holders which are then summarised in tables and illustrated in graphs. For ease of reference the mines were divided up into geographica l areas. Gold production revenue, lease and tax payments to the State and the amounts available to shareholders are summarised and compared for the various gold prices. The summaries show bold production remaining fairly constant at or just below the present level of about 900 000 kilograms per year until 1978 for Case A, 1979 for Cases B and C, 1983 for Case D, and 1984 for Case E. before declining progressively thereafter. Revenue following the same pattern as gold production for Case A , as is to be expected, but increasing to a peak of R1 466 million in 1977 for Case B before progressively declining, increasing to a peak of R2 434 million in 1982 for Case D before progressively declining, increasing to a peak of R3 478 million in 1983 for Case E but remaining above the 1973 level of R1 254 million until the year 2005. Lease and tax payments and amounts available to share-holders following the same pattern as that indicated by revenue reaching peaks of respectively R390 million and R268 million for Case B R485 million and R339 million for Case C R756 million and R536 million for Case D R1 000 million and R779 million for Case E. Following the recent monetary unrest, gold prices assumed for 1973 are too conservative. Should the present gold price of about $80 and the 1972 level of production of 909 000 kilograms continue for the remainder of 1973, then gold production, revenue, lease and tax payments and dividends as shown for Case C for the year 1975 will be applicable for 1973. This shams gold production of 919 520 kilograms, gold revenue of R 1690 million, lease and tax payments of R465 million, and dividends of R339 million. The effect of the higher gold price can be clearly seen when the fore-going figures are compared with the 1971 totals of gold production of 97 6,600 kilogr ams , revenue of R396 million from gold, lease and tax payments of approximately R139 million, and dividends of R142 million . Despite a decline in gold production, revenue is expected to be up by 8 9 % whilst lease and tax payments increase by 2 35% compared with a dividend increase of 139%. Finally certain tax concessions to increase productivity and the rebuy alleviate the labour shortage, prolong the li ves of the mines by mining lower grade ore, and encourage exploration was investigated and suggestions made. / Business Management / D. Com.

Thesis(MTech (Chem.Eng.Technology))--//Cape Technikon, 1999 / The gold mining industry has mainly relied upon the use of a highly polluting chemicals, such as mercury and cyanide, to recover gold from its ores. As environmental legislation has become more stringent in all countries and environmental protection has become the focus of world-wide research, development of environmental sound processes has been favoured. The Coal Gold Agglomeration (CGA) process is such a process which was developed some years ago and has the advantage in that gold is recovered by a procedure which has little or no effect on the environment. The CGA process is based on the hydrophobic characteristics of coal, gold and oil. Gold particles which are substantially free become attached to the coal-oil agglomerates during collision, and eventually penetrate into the agglomerates. The resulting agglomerates are recycled to increase the gold loading, separated from the slurry, burnt, ashed and smelted to produce gold bullion. Laboratory scale batch tests were performed on an artificial/synthetic gold ore, containing fine gold powder. The slurry was contacted with a mixture of coal and oil. i.e. coal-oil agglomerates, after which both the agglomerates and ore were analysed for gold. Operating parameters, such as the mode of contact between the coal-oil phase and the gold containing slurry, contact time of the slurry and the coal-oil phase, means of separating the coal-oil gold agglomerates from the slurry, coal to ore, coal to oil and water to ore ratios, type of oil, effect of collectors and the mineralogy of the ore on the gold recovery were investigated. Results have shown that stirring the coal-oil phase and the slug yielded higher gold loadings than shaking and the traditional rolling bottle technique. BI increasing the time of contact between the coal-oil phase and the gold slurry. the final gold loading in the agglomerates increases, until an equilibrium value is reached. An increase in the amount of coal, together with a decrease in the amount of water used in the slurry, has shown to increase gold recoveries. Furthermore, by varying the concentration and volume of a collector. such as potassium amyl xanthate (PAX) enhanced the settling rate and enabled the effectiveness of separation. Moreover, it was found that the gold loading on the coal-oil phase increased after recycling it. Further tests were performed on a real ore sample and after X-ray Diffraction (XRD) analysis, it was found that certain minerals other than gold was transferred to the coal-oil phase. The theoretical foundation of the CGA process is based on the difference in free energy and was expressed as a function of the interfacial tensions and three-phase contact angles between gold, oil and water, together with the ratio of coal-oil agglomerate to gold particle radii, as the free energy is a measure of the thermodynamic stability and hence, partly a measure of gold recoveries, meaningful predictions as to gold recoveries were made by performing a sensitivity analysis on the variables connected to the free energy, It was, however, found that some operating parameters, which were linked to other factors, such as the maximum gold transfer into coal-oil phase and the separation efficiency of the agglomerates. were vital to be taken into account when predictions as to gold recoveries were made. Therefore, the gold recoveries were found to be a function of the thermodynamic stability as well as the maximum gold transfer into the coal-oil phase and the separation efficiency of the agglomerates, The meaningful information gained by performing the theoretical investigations were applied and linked to gold recoveries, thereby providing useful explanations as to the typical gold recoveries obtained during experimentation. A comparative study on mercury amalgamation was done to evaluate the performance of the CGA process. It was found that the CGA process yielded better gold recoveries than amalgamation, which makes it the better process both in terms of recoveries as well as environmental safety, A further application of the theoretical knowledge was, however, very useful to explain the tendency of the CGA process yielding the better results.

Thesis submitted in fulfilment of the requirements for the degree Magister Technologiae: Chemical Engineering in the Faculty of Engineering at the Cape Peninsula University of Technology 2014 / The legislative requirements for handling cyanide containing wastewater have become stringent internationally. Cyanide properties make it indispensable in the mining industry especially for gold recovery. The resultant wastewater generated is discarded to tailing ponds. Any leakages or total collapse of tailing ponds can result in the contamination of surface water bodies; endangering aquatic organisms’ and humans’ alike. The over reliance on physical and/or chemical treatment methods for cyanide wastewater treatment is not sustainable due to high input costs and the generation of by-products. A feasible alternative treatment method for cyanide contaminated wastewater is the biodegradation method, as a wide range of microorganisms can degrade cyanide. In this study, the cyanide biodegradation ability of Fusarium oxysporum was assessed in two stages. Firstly, optimal operating conditions for maximum cyanide biodegradation were determined using a central composite design (CCD) at an elevated cyanide concentration, i.e. 500 mg F-CN/L. Thereafter, using the optimum conditions obtained, (i.e temperature 22°C and pH 11), cyanide biodegradation kinetics and microbial growth kinetics in the cultures at lower cyanide concentrations of 100, 200 and 300 mg F-CN/L were assessed. This was followed by the assessment of cyanide biodegradation at a temperature of 5°C, which was used to simulate winter conditions. In general, lower cyanide concentrations are used in the extraction of gold, therefore, the resultant wastewater will contain free cyanide concentration less than 300 mg F-CN/L. For the first stage of experiments, an isolate, Fusarium oxysporum from cyanide containing pesticides was cultured on potato dextrose agar (PDA) plates, followed by incubation at 25°C for 5 days. A response surface methodology (RSM) was used to evaluate design parameters for the biodegradation of cyanide by this fungus. The temperature evaluated at this stage ranged from 9°C to 30°C and pH range of 6 to 11 in cultures solely supplemented with agrowaste, i.e Beta vulgaris waste. Beta vulgaris is commonly known as Beetroot. The Fusarium oxysporum inoculum (2% v/v) was grown on a Beta vulgaris waste solution (20% v/v), as the sole carbon source in a synthetic gold mine wastewater (39% v/v) containing heavy metals; arsenic (7.1 mg/L), iron (4.5 mg/L), copper (8 mg/L), lead (0.2 mg/L) and zinc (0.2 mg/L), for 48 hours using a rotary shaker at 70 rpm. Thereafter, free cyanide as a potassium cyanide solution (39% v/v), was added to the cultures to make a final cyanide concentration of 500 mg F-CN/L in the culture medium which was incubated for a further 72 hours at 70 rpm. Optimal operating conditions for the biodegradation of cyanide were then determined using a numerical option in the Design-Expert® software version 6.0.8 (Stat-Ease Inc., USA). Subsequently, using the optimal pH obtained (pH =11) and a preselected temperature of 5°C (to represent winter conditions), cyanide biodegradation rates and microbial growth kinetic studies were carried out using Beta vulgaris waste containing a Fusarium oxysporum (0.7% v/v; grown overnight) inoculum in wastewater (32.7% v/v) and potassium cyanide in phosphate buffer (53.7% v/v). The cultures contained 100, 200 and 300 mg F-CN/L. The cultures were incubated in an orbital shaker at 70 rpm for 144 hours and samples taking every 24 hours. An Ordinary Differential Equation (ODE) solver (Polymath) was used for modelling cyanide degradation kinetics while the Monod’s growth kinetic model was used to monitor the microbial growth parameters of the cultures. For the first stage, the optimum operating conditions were determined as a temperature of 22°C and a pH of 11 for maximum cyanide biodegradation of 277 mg F-CN/L from an initial cyanide concentration of 500 mg F-CN/L over a 72 hour period, with residual ammonium-nitrogen and nitrate-nitrogen of 150 mg NH4+-N/L and 37 mg NO3--N/L, respectively. Although, the residual ammonium-nitrogen inhibited cyanide biodegradation, it was consumed as a nitrogen source for microbial growth. The Beta vulgaris waste was determined to be a suitable substrate for cyanide degradation. From the biodegradation response quadratic model, temperature was determined to influence cyanide biodegradation. For the cyanide degradation kinetics, at an optimum temperature of 22°C, the biodegradation efficiency was 77%, 58% and 62% with the corresponding maximum microbial population of 1.56 x 107, 1.55 x 107 and 1.57 x 107 CFU/mL for 100, 200 and 300 mg F-CN/L, being achieved. An indication that the F. oxysporum cultures were efficient at lower cyanide concentration. Furthermore, at a temperature of 5°C, the biodegradation efficiency, although slightly lower, was 51%, 43% and 44% with the corresponding maximum microbial population of 1.21 x107, 1.11 x 107 and 1.12 x 107 CFU/mL for 100, 200 and 300 mg F-CN/L cultures, respectively, with minimal differences observed for cultures with 200 and 300 mg F-CN/L. The cyanide biodegradation rates increased with temperature increases and varied with different cyanide concentrations below 500 mg F-CN/L. The estimated energy of activation for cyanide degradation for a change in temperature from 5°C to 22°C using the Arrhenius model was 19.6, 12.7 and 14.9 kJ/mol for 100, 200 and 300 mg F-CN/L, respectively. The means and standard deviations for rate of degradation of cyanide at 5°C and 22°C for the ODE models was 0.0052 (± 0.0011) h-1 and 0.0084 (± 0.0027) h-1, respectively. The inhibitory effect of the cyanide was quantitatively pronounced under cold temperature as the heavy metals, residual ammonium-nitrogen and nitrate-nitrogen hindered the cyanide degradation. Similarly, microbial growth rates increased with a temperature rise (from 5°C to 22°C), resulting with a reduction in the microbial populations’ doubling time. When compared with the simulated winter conditions, the specific population growth rate increased 4-fold, 5-fold and 6-fold in 100, 200 and 300 mg F-CN/L, respectively, for higher temperatures; an indication that the Fusarium oxysporum isolate prefers higher temperature. The estimated energy of activation for cellular respiration was 44.9, 54 and 63.5 kJ/mol for 100, 200 and 300 mg F-CN/L cultures, respectively, for the change in temperature from 5°C to 22°C. The means and standard deviations of microbial growth rate at 5°C and 22°C were: 0.0033 (± 0.0013) h-1 and 0.0151 (± 0.0027) h-1, respectively. The difference in error (standard deviation) of the cyanide biodegradation rate and microbial growth rate was insignificant (0.02% at 5°C) especially at temperature 22°C where there were minimal differences, indicating the reliability and reproducibility of this biodegradation system in batch operated bioreactors.

M.Comm. / Many variables exist that influence buyer behaviour in the narrow reef gold mining market. Since some variables are real but subjective in nature, such as the opinion and charisma of mine managers or influential individuals, it is difficult to quantify and analyse them. The question is ? Which variables, 8 quantifiable or not, are more dominant in shaping buyer behaviour and how should they be prioritised? What is needed is a logical segmentation model which reflects true buyer behaviour in order to shape future strategies in AEL so that the overall company objectives can be met. Each segment should then be analysed and considered regarding attractiveness in satisfying needs and the ability to add value both to the customer and to AEL. It is also required to target market segments and develop a marketing mix for them so that AEL is correctly positioned to retain the markets it choose to compete in. The problem is the failure to identify market areas of similar response which are relatively stable and can be used to select areas where maximum value can be added to the customer and to the company and can be used to shape and define future direction. The following objectives have been set for this study:The establishment of a market segmentation model which will identify and explain the basis of similarities and differences in buyer behaviour groups which is sufficiently large and stable in order to focus future strategies. - The interpretation of the segmentation model in the light of the strengths, weaknesses, opportunities and threats of the company in order to target markets best suited to the potential of the company. - Development of strategies and positioning in the target markets to strengthen the chance of success.

The project area is situated within the Tugela Valley, located in the Northern Marginal Zone of the Natal Structural and Metamorphic Province, and this work outlines the different styles of gold mineralization found in the Tugela Valley. Two different styles have been recognized and both have economic significance:- 1) Epigenetic shear zone-hosted gold occurs in late-stage relatively undeformed thin quartz veins confined to shear zones, and is present in both the greenschist facies Natal Thrust Belt and the amphibolite facies Natal Nappe Complex. However the vast majority of these occurrences are concentrated within the thrust front (i.e. the Natal Thrust Belt). The gold grades (up to 7 g/t) and the hydrothermal alteration assemblages associated with the epigenetic deposits have been documented. 2) An as yet unrecognized occurrence of syngenetic gold mineralization is found associated with the sediment-hosted exhalative massive, to semi-massive, sulphides of the iThuma prospect, located within the amphibolite facies Natal Nappe Complex. Here gold (up to 3 g/t) is concentrated together with the main sulphide are, as well as some gold enrichment (230ppb) in the hydrothermally altered footwall feeder pipe. It is proposed that the epigenetic mineralization was formed as a consequence of the northward directed abduction of the major thrust slices of the Natal Nappe Complex. This increased the permeability of the rocks and provided channelways for the focussing of fluids. Deposition took place at the thrust front where metamorphic hydrothermal fluids interacted with meteoric water.