3. Electronic Theses and Dissertations (ETDs) - All submissions
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Item A tale of two cities? an examination of the re-imagining of gold mining history at Gold Reef City and in Johannesburg's Main Street precinct(2009-02-02T10:38:34Z) Van Straaten, Philippa SarahAbstract This research report attempts to examine how the story of gold, and gold mining, is told, and is being retold, at both the Victorian- themed Gold Reef City theme park and in within the Main Street mining precinct in the Johannesburg Central Business District (CBD). The report will therefore look at how imbued ideologies have resulted in a particular formation of the mining heritage shown in both themed spaces. Works by de Certeau (1988) and Eco (1990), for example, form a framework for academic discourse around practiced space within the ‘city’, and the nature of hyperreality. Overall, and including results from participant observation at the theme park, and sample surveys undertaken in the Main Street precinct, one is able to better attempt an understanding of how the story of gold at both sites has been created by certain ideologies, and examine them in light Johannesburg’s changing persona in light of global influences.Item The distribution and abundance of herpetofauna on a Quaternary aeolian dune deposit : Implications for strip mining(2008-11-04T11:31:54Z) Maritz, BryanExxaro KZN Sands is planning the development of a heavy minerals strip mine south of Mtunzini, KwaZulu-Natal, South Africa. The degree to which mining activities will affect local herpetofauna is poorly understood and baseline herpetofaunal diversity data are sparse. This study uses several methods to better understand the distribution and abundance of herpetofauna in the area. I reviewed the literature for the grid squares 2831DC and 2831 DD and surveyed for herpetofauna at the study site using several methods. I estimate that 41 amphibian and 51 reptile species occur in these grid squares. Of these species, 19 amphibian and 39 reptile species were confirmed for the study area. In all, 29 new unique, grid square records were collected. The paucity of ecological data for cryptic fauna such as herpetofauna is particularly evident for taxa that are difficult to sample. Because fossorial herpetofauna spend most of their time below the ground surface, their ecology and biology are poorly understood and warrant further investigation. I sampled fossorial herpetofauna using two excavation techniques. Sites were selected randomly from the study area which was expected to host high fossorial herpetofaunal diversity and abundance. A total of 218.6 m3 of soil from 311 m2 (approximately 360 metric tons) was excavated and screened for herpetofauna. Only seven specimens from three species were collected. All were within approximately 100 mm of the surface even though some samples removed soil 1 m below the surface. There was no detectable difference in fossorial herpetofaunal density (individuals.m-2) between methods or from areas under different land uses. Neither soil compaction nor land use nor soil texture predicted fossorial herpetofaunal density or abundance. The data suggest that fossorial herpetofauna occur at extremely low densities in the area. This finding has implications for population estimates and conservation measures for these species. In order to better understand the effects of land use on herpetofaunal diversity, I used sample-based rarefaction curves to compare the diversity of the herpetofaunal species assemblages occurring in each of the four main land uses on the study site. Forest areas hosted significantly higher diversity than grasslands and the two agricultural mono-cultures, Eucalyptus and sugarcane plantations. Additionally I demonstrated empirically that riparian woodlands host higher species richness and herpetofaunal abundance than non-riparian areas. Potential reasons for the apparently suppressed diversity of these areas include the use of pesticides and/or herbicides, harvesting regimes, and the reduction in habitat heterogeneity. The potential value of riparian woodlands as refugia and corridors that could facilitate recolonisation of revegetated areas post-mining is discussed. Negative influences of mining activities on local herpetofauna are of particular interest given the potential and verified presence of several threatened taxa in the area including Bitis gabonica, Python natalensis, Afrixalus spinifrons, Hemisus guttatus and Hyperolius pickersgilli. These, as well as the “conservation needy” species proposed in a specialist report on the impacts of the mine on local herpetofauna are discussed in the light of my fieldwork. Mitigatory measures are required to reduce the negative impacts likely to be experienced by certain threatened taxa. I discuss a proposal for the development of a wetland reserve targeting, among other amphibian species, H. pickersgilli.Item The impact of HIV/AIDS on mortality at a South African platinum mine(2008-05-14T11:37:50Z) Dowdeswell, Robert JosephABSTRACT Background: There is a paucity of empirical data on the impact of HIV/AIDS on mortality in the mining industry in the pre-ART era. Such data will provide a baseline against which the efficacy of antiretroviral treatment can be measured into the future. Objectives: To measure all-cause mortality in a population of platinum miners between 1992 and 2002, the impact of HIV/AIDS on mortality in this group and to determine the pattern of other cause-specific mortality. Methods: This was a primary analysis of mortality in an open cohort of male semi- and unskilled workers at a platinum mine. Using Poisson regression, all-cause, HIV/AIDSrelated and other cause-specific mortality rates and rate ratios were calculated by age and calendar year. Results: There were 1986 deaths in the cohort of 29954 subjects who contributed 200657 person years of follow up over the 11 year period of the study. Crude all-cause mortality increased from a base of 5.1 per 1000 person years at risk (pyar) (95% CI 4.2- 6.2) in 1992 to 20.4 per 1000 pyar (95% CI 18.3-22.8) in 2002. Age-adjusted all-cause mortality increased more than three-fold from 1992 to 2002 (RR 3.2, 95% CI 2.5-4.0). The excess mortality was attributed to HIV/AIDS-related deaths which increased from 0% in 1992-1994 to 5.1% of total deaths in 1995 and reached 63.3 % of deaths in 2002. Mortality due to other communicable diseases, non-communicable diseases and injuries remained stable throughout the study period. Conclusion: The impact of the HIV/AIDS epidemic on mortality in this group of platinum mine workers has been profound and comparable to that experienced by the general South African population. The data reported here provide a baseline to measure the impact of antiretroviral treatment on the future course of mortality due to the epidemic.Item Electric rock breaking for south african ore bodies(2007-02-28T12:48:09Z) Ilgner, Hartmut JohannesAlthough pulsed power has been used in many parts of the world over the last few decades to initiate high-voltage discharges through rock, no systematic test work on South African ore bodies and related rock types has been done so far. As part of CSIR Miningtek’s integrated approach of combining underground comminution with a novel Tore© hydrotransport system, which has been shown to operate well with coarse particles up to 10 mm, various rock types were fragmented in single discharge mode under laboratory conditions. The work was conducted at the University of the Witwatersrand’s high-voltage laboratory with a custom-designed test rig. The rig configuration was based on a critical review and analysis of the literature and on assessments of existing test facilities elsewhere. Core samples with diameters ranging from 16 to 48 mm were cut from test specimens with thicknesses ranging from 8 to 48 mm. Rock types included Ventersdorp Contact Reef, Carbon Leader, Elsburg Formation, UG2 and Merensky, as well as pure quartz, shales, lava and dykes. A six-stage Marx generator provided a voltage rise time of 2 000 kV/μs to create a discharge through the rock, in preference to a discharge through the surrounding water, which acts as an insulator at ramp-up times faster than 0,5 μs. High-speed photography, and an analysis of the voltage and current signals for various rock types and for water alone, were used to quantify the potential benefits of rock breaking by electric discharge. It was found that some Kimberlite specimens and mineralised gold-bearing reefs were much easier to fragment than hanging wall or footwall material. Merensky reef appeared to be more susceptible than the less brittle UG2 material. A correlation was derived between the dynamic resistivity of various rock types, measured at 16 MHz excitation frequency, and the electrical breakdown strength at which discharge took place. The fragments created had a more cubical shape than would be created by conventional impact crushing. However, the high voltage requirements of about 30 to 35 kV per millimetre of rock thickness would necessitate not only efficient mechanical and electrical contact between the electrodes and the rock, but also considerable safety features for underground installations. The clearly identified, preferential fracturing of reef rock types, compared with the hanging or footwall materials, suggests that the greater benefit of electric rock breaking may lie in primary rock breaking as a mining method, rather than in secondary comminution of broken rock to enable hydraulic transportation by pipeline to surface.Item Exploring barriers to land accessibility for low-income housing delivery: A case of buffers of open space on the mining belt between Johannesburg CBD and Soweto(2007-02-22T12:39:55Z) Baloyi, Hlengani GoldwinThis is an exploratory study which seeks to look at barriers to land accessibility for the construction of low-income or affordable housing on former mining lands between Soweto and Johannesburg CBD. Based on the findings, there are various barriers which inhibit and threaten the construction of houses on former mining lands. These barriers, exposed by the findings of this report are radon, mine dust - both of which pose a serious health risk to residents if exposed to it for a long period of time - high prices of land, inadequate funding for housing subsidies and the National Nuclear Regulator’s too strict and uncompromising stance on housing construction on contaminated lands. The conclusion drawn by this report is that the government, owners of former mining land and the National Nuclear Regulator need to co-operate and work together towards finding a common ground in order to enhance the possibility of a total removal of these barriers, so that the previously marginalized citizens can afford to own houses closer to the Central Business District of Johannesburg.