ETD Collection

Permanent URI for this collectionhttps://wiredspace.wits.ac.za/handle/10539/104


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Now showing 1 - 3 of 3
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    Adsorption studies on supported gold catalysts using temperature programmed desorption (TPD)
    (Wits University, 2007-06) Linganiso, Linda, Zikhona
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    Evaluation of gold as an investment asset: the South African context
    (2013-07-26) Pule, Barrend Pule
    This study examines potential benefits of investing in various gold investment vehicles in terms of risk and return from a typical South African investor’s perspective. Furthermore, the study examines the relationship between gold price and South African macroeconomic variables. Data used in the study comprises of monthly closing share price data of JSE listed gold mining companies, gold price, Krugerrand coin, NewGold ETF, FTSE/JSE all share index, gold mining index, unit trust index (gold & precious metals), real GDP, rand/dollar exchange rate, repo rate and CPI. It was found that gold bullion produced superior abnormal returns and yielded greater capital growth compared to the JSE all share index. However, the JSE all share index exhibit lower volatility compared to gold bullion. Abnormal returns for JSE listed gold mining companies tend to differ substantially from gold bullion abnormal returns. Gold mining companies exhibit added risk which cannot be attributed to the gold bullion. Gold has a potential to reduce systematic risk when added to a portfolio of stocks. A multiple regression model was estimated which relates gold price to South African macroeconomic variables. It was found that gold price depends on real GDP and rand/dollar exchange rate.
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    Optimizing the operating conditions of gold elution and electrowinning for Tau Lekoa stream at Kopanang gold plant
    (2008-06-25T08:25:30Z) Lunga, Alfred Lodi
    The final gold product of Tau Lekoa mine has a low fineness. This is caused by high concentration of bases metals in the reefs. Some of these base metals together with gold are leached with cyanide and are loaded into carbon. If not adequately controlled, they may elute with gold and contaminate the final product in the electrowinning process. Based on the understanding of the kinetics of the elution, four parameters, namely temperature, flow rate, free caustic soda concentration and cyanide strength, were evaluated first for the elution process. Experimental runs on the plant scale did prove that the first three parameters are the predominant parameters that maintain base metals in the carbon during the elution and therefore assist in the improvement of the fineness of the final product. Recommendations were made to change the operating conditions and the fineness of the gold did improve from 80% to 84 %. In addition, a thermodynamic model that took to consideration the competition of gold and nickel was developed for the electrowinning process. This model showed that the deposition of gold and nickel during the electrowinning was dependant of their concentrations and temperature. The single pass efficiencies and the deposition rates were also tracked during the experimental. Based on the finding on the reduction of electrowinning time, the fineness of the final product was improved from 84% to 85%. As the refining cost depends on the fineness of gold, the improved fineness means that the gold content in the bullion is increased and the impurities are decreased, therefore, the refining cost will decrease as lower penalty costs are charged for the treatment of the bullion with high fineness. The recommendations of the changes have been implemented permanently and these did show permanent improvement of the fineness.