• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 29
  • 1
  • 1
  • 1
  • Tagged with
  • 47
  • 47
  • 11
  • 10
  • 10
  • 10
  • 6
  • 6
  • 5
  • 4
  • 4
  • 4
  • 4
  • 4
  • 4
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
21

Job insecurity, coping and health-related behaviour / Angelique Marie Fourie

Fourie, Angelique Marie January 2005 (has links)
Across the world, job insecurity plays a critical role in organisations. This insecurity affects not only the individual, but also the organisation. In South Africa, the Employment Equity Act (No. 55 of 1998), and the Broad-Based Socio-Economic Empowerment Charter for the South African Mining Industry (Mining Charter), brought changes to the mining industry policies and decision-making process in terms of selection and recruitment, which could in turn lead to feelings of job insecurity. Other factors such as the availability of gold left to be mined, restructuring and strikes increase work-related stress. The objectives of this study were to investigate the role of job insecurity in predicting health related behaviours, and to determine whether coping moderates the effect of job insecurity on health behaviours for a group of managers in a South African gold mining company. A cross-sectional design was used. The study population (n = 206) consisted of managers in a gold mining company in South Africa The Job Insecurity Scale, Cybernetic Coping Scale and Health Complaints Questionnaire were used as measuring instruments. Descriptive statistics (e.g. means, standard deviations and kurtosis) were used to analyse the data. Hierarchical multiple regression analysis was used to test for the hypothesized moderating effect of coping on the relation between job insecurity and health-related behaviours. The results of the regression analyses showed that qualitative job insecurity was a significant predictor of health complaints. Qualitative job insecurity was also a significant predictor of health complaints in employees who smoked cigarettes and drank alcohol, and exercised at least once a week. Quantitative job insecurity did not play a role in predicting health-related behaviour. Coping did not moderate the effects of job insecurity for employees with health complaints. Rather, it is suggested that using negative coping behaviours may actually contribute to health complaints. Recommendations for future research are made. / Thesis (M.A. (Industrial Psychology))--North-West University, Potchefstroom Campus, 2006.
22

Developing a generic model of the initial review process for a gold mine shaft business unit / Theunis Christoffel Meyer

Meyer, Theunis Christoffel January 2003 (has links)
South Africa is one of the world's foremost mining nations and mining and its associated industries continue to form the cornerstone of the country's economy. However, the mining industry has, by its very nature, the potential to endanger human health and safety, as well as the physical environment. Consequently, mining will always contend with major environmental challenges and remain under constant public pressure to demonstrate its commitment to responsible environmental management. The key to effective environmental management is the use of a systematic approach to plan, control and improve environmental efforts. An Environmental Management System (EMS) employs such an approach and allows organisations to address environmental concerns in an orderly and consistent manner. Such a system allows organisations to anticipate and meet their environmental objectives and to ensure ongoing compliance with national and/or international requirements. An organisation with no existing EMS should, initially, establish its current position with regard to the environment by means of an initial review process. The aim should be to consider all environmental aspects of the organisation as a basis for establishing the EMS. Although a few gold mines in South Africa have implemented an EMS, the question of which significant environmental aspects need to be managed in such a system at a deep level gold mine shaft, remains largely unanswered. This study endeavoured to provide answers to this question and develop a generic model for the initial review process of a deep level gold mine shaft. The development of such a model should facilitate the development and implementation of an EMS at such shafts, thereby contributing to reduce the environmental impact of gold mines. The research consisted of a literature review of national and international literature on the topic and a comparative empirical study, which evaluated the mining operations of two deep level gold mine shafts. Data collection and analysis was done according to the IS0 14015 guideline on the environmental assessment of sites and organisations. Other techniques used included business process analysis, the use of modified Leopoldt matrices and risk analysis to determine the significance of the environmental impacts and aspects. This study contributed to a generic model for the initial environmental review process that precedes the development of an EMS at deep level gold mine shafts through: developing a generic sub-model that can be used to determine the scope of any deep level gold mine shaft; identifying some of the significant environmental impacts and aspects of deep level gold mine shafts, as well as identifying some generic business activities that are potentially destructive and carry a high risk of causing significant negative environmental impacts. / Thesis (M. Environmental Management)--North-West University, Potchefstroom Campus, 2004.
23

Job insecurity, coping and health-related behaviour / Angelique Marie Fourie

Fourie, Angelique Marie January 2005 (has links)
Across the world, job insecurity plays a critical role in organisations. This insecurity affects not only the individual, but also the organisation. In South Africa, the Employment Equity Act (No. 55 of 1998), and the Broad-Based Socio-Economic Empowerment Charter for the South African Mining Industry (Mining Charter), brought changes to the mining industry policies and decision-making process in terms of selection and recruitment, which could in turn lead to feelings of job insecurity. Other factors such as the availability of gold left to be mined, restructuring and strikes increase work-related stress. The objectives of this study were to investigate the role of job insecurity in predicting health related behaviours, and to determine whether coping moderates the effect of job insecurity on health behaviours for a group of managers in a South African gold mining company. A cross-sectional design was used. The study population (n = 206) consisted of managers in a gold mining company in South Africa The Job Insecurity Scale, Cybernetic Coping Scale and Health Complaints Questionnaire were used as measuring instruments. Descriptive statistics (e.g. means, standard deviations and kurtosis) were used to analyse the data. Hierarchical multiple regression analysis was used to test for the hypothesized moderating effect of coping on the relation between job insecurity and health-related behaviours. The results of the regression analyses showed that qualitative job insecurity was a significant predictor of health complaints. Qualitative job insecurity was also a significant predictor of health complaints in employees who smoked cigarettes and drank alcohol, and exercised at least once a week. Quantitative job insecurity did not play a role in predicting health-related behaviour. Coping did not moderate the effects of job insecurity for employees with health complaints. Rather, it is suggested that using negative coping behaviours may actually contribute to health complaints. Recommendations for future research are made. / Thesis (M.A. (Industrial Psychology))--North-West University, Potchefstroom Campus, 2006.
24

The role of vegetation in characterising landscape function on rehabilitating gold tailings / A.S.H. Haagner

Haagner, Adrian Sigmund Harold January 2008 (has links)
Gold mine waste poses a significant challenge for rehabilitation practitioners and can negatively impact on soil, air, surface water and groundwater quality. This, in turn, can affect the environmental quality of humans and other biota in nearby settlements and surrounding ecosystems. All mines are required to have a plan in place to impede or mitigate these environmental impacts and to ensure that all legislation is complied with to apply for closure. Site closure is the eventual goal of all mine residue complexes, as it is the stage at which a company becomes released from all legal and financial liability. The South African legislation is comprehensive and essentially requires that all latent and residual environmental impacts are addressed and that an end land-use designation is put in place that conforms to the principles of sustainable development. The Chemwes Tailings Storage Facility complex near Stilfontein was monitored to provide a strategic assessment of the state of the rehabilitation, and to provide recommendations for the successful remediation of problem sites. A combination of vegetation sampling, landscape function assessments and substrate chemical analyses were conducted to gain a predictive understanding of rehabilitation progress. The monitoring was conducted over two years across a chronosequence of rehabilitating sites from tailings dam slopes and an adjacent spillage site. An undisturbed grassland and a starter-wall served as reference sites. The data were first analysed independently and then by making use of multivariate data ordinations. This allowed for holistic investigations of the relationships between sites, substrate chemistry, vegetation composition and landscape function. The results showed that the tailings dams had a distinctly different suite of vegetation from the reference sites, but had no statistically significant differences in composition across the rehabilitating chronosequence. There were positive correlations between rehabilitation site age and landscape function indices, suggesting that some aspects of ecosystem development were occurring over time. In some sites, deterioration in the substrate quality as a growth medium was observed with increases in acidity and salinity. This was most likely caused by pyrite oxidation in the tailings and the high concentrations of free salts. The increasing acidity and salinity resulted in vegetation senescence and declines in landscape function. However, those sites that possessed higher landscape function appeared to have the ecosystem processes in place that temporarily suppressed negative chemical changes. Whilst this was encouraging,the rehabilitation chronosequence had not yet proven the self-sustainability that it would require for closure purposes. Further monitoring would be required over time. The sustainability of the rehabilitating chronosequence was brought into question by the high acid-forming potential of the tailings growth medium. Concerns were also raised over the ability of the established vegetation cover to persist under conditions of increasing stress and disturbance. Furthermore, the land-use capabilities of the sites are limited by current rehabilitation procedures and various recommendations were made to rectify this. A more streamlined monitoring framework for the tailings complex was also proposed. The contribution of this work lies in its holistic integration of monitoring techniques and the meaningful analysis of ecosystem function, an aspect largely ignored in minesite rehabilitation. / Thesis (M.Sc. (Environmental Sciences and Management))--North-West University, Potchefstroom Campus, 2009.
25

The role of vegetation in characterising landscape function on rehabilitating gold tailings / A.S.H. Haagner

Haagner, Adrian Sigmund Harold January 2008 (has links)
Gold mine waste poses a significant challenge for rehabilitation practitioners and can negatively impact on soil, air, surface water and groundwater quality. This, in turn, can affect the environmental quality of humans and other biota in nearby settlements and surrounding ecosystems. All mines are required to have a plan in place to impede or mitigate these environmental impacts and to ensure that all legislation is complied with to apply for closure. Site closure is the eventual goal of all mine residue complexes, as it is the stage at which a company becomes released from all legal and financial liability. The South African legislation is comprehensive and essentially requires that all latent and residual environmental impacts are addressed and that an end land-use designation is put in place that conforms to the principles of sustainable development. The Chemwes Tailings Storage Facility complex near Stilfontein was monitored to provide a strategic assessment of the state of the rehabilitation, and to provide recommendations for the successful remediation of problem sites. A combination of vegetation sampling, landscape function assessments and substrate chemical analyses were conducted to gain a predictive understanding of rehabilitation progress. The monitoring was conducted over two years across a chronosequence of rehabilitating sites from tailings dam slopes and an adjacent spillage site. An undisturbed grassland and a starter-wall served as reference sites. The data were first analysed independently and then by making use of multivariate data ordinations. This allowed for holistic investigations of the relationships between sites, substrate chemistry, vegetation composition and landscape function. The results showed that the tailings dams had a distinctly different suite of vegetation from the reference sites, but had no statistically significant differences in composition across the rehabilitating chronosequence. There were positive correlations between rehabilitation site age and landscape function indices, suggesting that some aspects of ecosystem development were occurring over time. In some sites, deterioration in the substrate quality as a growth medium was observed with increases in acidity and salinity. This was most likely caused by pyrite oxidation in the tailings and the high concentrations of free salts. The increasing acidity and salinity resulted in vegetation senescence and declines in landscape function. However, those sites that possessed higher landscape function appeared to have the ecosystem processes in place that temporarily suppressed negative chemical changes. Whilst this was encouraging,the rehabilitation chronosequence had not yet proven the self-sustainability that it would require for closure purposes. Further monitoring would be required over time. The sustainability of the rehabilitating chronosequence was brought into question by the high acid-forming potential of the tailings growth medium. Concerns were also raised over the ability of the established vegetation cover to persist under conditions of increasing stress and disturbance. Furthermore, the land-use capabilities of the sites are limited by current rehabilitation procedures and various recommendations were made to rectify this. A more streamlined monitoring framework for the tailings complex was also proposed. The contribution of this work lies in its holistic integration of monitoring techniques and the meaningful analysis of ecosystem function, an aspect largely ignored in minesite rehabilitation. / Thesis (M.Sc. (Environmental Sciences and Management))--North-West University, Potchefstroom Campus, 2009.
26

The geology of the Vaal Reefs Gold Mine, Western Transvaal

Jacob, Roger E January 1966 (has links)
Rocks forming part of the Main-Bird Series and the Kimberley-Elsburg Series of the Upper Division of the Witwatersrand System are found in the mine. The sequence studied starts with the Middle or MB 6 Zone of the Livingstone Stage followed by the Upper or MB 5 Zone. The Vaal Roof, forming the base of the Vaal Stage, rests disconformably on the older rocks. The Stage is subdivided into the Vaal Reef Zone, the Lower Vaal Zone, the Argillaceous Zone and the Upper Vaal Zone. The lower and upper contacts of the Argillaceous Zone are gradational. The Kimberley Stage follows unconformably and comprises the basal Gold Estates Conglomerate Zone, the Denny's Zone and the Gold Estates Zone. The overlying Elsburg Stage may be subdivided into the Bastard Zone and the Upper Elsburg Zone on lithological grounds. Most of the rocks are indurated quartz wackes with only a few orthoquartzite horizons such as the Denny's Zone and the immediate hangingwall of the Vaal Reef. Microscopically the rocks consist of detrital quartz and chert grains in a fine-grained sericitic to partly siliceous matrix which may constitute more than 50 per cent of the rock. Heavy minerals, such as zircon, chromite, rutile, leucoxone, pyrite, tourmaline, epidete, apetite and magnetite, occur in most of the zones. The Vaal Reef, the economic horizon, is of small-pebble, oligomictic conglomerate, often containing thucholite seams and granules, and varying in thickness from a mere parting to more than five feet. There appears to be a correlation between greater pebble size and higher ore grade but no correlation of sorting coefficients and gold value. The mineralogy of the Vaal Reef was studied by means of polished sections and heavy mineral concentrates. The minerals identified include gold, pyrite of several ages, pyrrhotite, chalcopyrite, uraninite, galena, brannerite, gersdorffite or cobaltite, skutterudite, linnacite, danaite, niccolite, pentlandite, magnotite, zircon, chromite, rutile, leucoxine, monazite, sphalerite, tourmaline, and fluorite. From a study of the silver content of gold in the Vaal Roof it is concluded that the variations in apparent fineness are a reflection of the composition of the gold in the original source rocks. There is a definite uranium-gold relationship in the Vaal Roof. With increase in grade the amount of U₃O₈ increases but the U₃O₈:AU ratio decreases. Use of these reations may indciate the payability in cases of incomplete core recovery.The intrusive rocks were studies in detail. Six types of intrusive rocks were found. From oldest to youngest those are quartz diabase (of three varieties), amygdaloidal diabase, ilmenite mela-microdiorite, mottled microdiorite, olivine lamprophyre and ankeritic beforsite, ranging in age from Lower Ventersdorp to post-Karroo. Most of the intrusives are highly altered due to the effects of regional metamorphism and deuteric alteration. Later formations, such as the Langgeleven and Allanridge Formations of the Ventersdorp System and the Black Roof and Dolomite Series of the Transvaal System, occur on the property. The various formations have been subjected to faulting and folding.
27

Suction induced shear strength of gold mine tailings

Westraad, Delme 10 June 2005 (has links)
The disposal of fine-grained mining and industrial waste by formation of hydraulic-fill tailings dams is becoming a design and construction activity of increasing scale. In light of the increasing pressure on the mining industry to sustain stringent safety and environmental standards it is becoming more important to gain technical knowledge of the waste problem. The upper layers of the tailings residue dams are in the unsaturated state with the matric suction component contributing to the overall shear strength. The ability to incorporate the matric suction component in shear strength calculations is important to safe design. This research project investigates the use of the mid-plane suction probe to measure matric suction. The results obtained from the probe is used along with various tests to construct a complete soil-water characteristic curve for Mispah gold tailings as well as to investigate suction induced shear strength of drying tailings with depth. The tests were conducted on gold tailings from Vaal Operation’s Mispah tailings dam. The laboratory tests consisted of a trough test, to determine the soil-water characteristics of the gold tailing and also a drying box test that simulated the drying and desiccation of the gold tailings in the daywall. The project concluded that the mid-plane suction probe could be used with acceptable accuracy to determine soil suctions. The model for the prediction of the soil water characteristic curve, derived by Fredlund and Xing (1992), was used successfully to predict the complete soil water characteristics curve for Mispah gold tailings. The equation derived by Vanapalli et al. (1996) was successfully used to calculate both the normal and suction induced shear strength of gold mine tailings using either the volumetric water content from the extracted samples or from the soil water characteristic curve. / Dissertation (MEng (Geotechnical Engineering))--University of Pretoria, 2006. / Civil Engineering / unrestricted
28

Sedimentation and desiccation of gold mine tailings

Wortmann, Heidi 05 November 2007 (has links)
South Africa, with its world leadership in the mining sector, and well-developed industrial sector, understandably has many tailings dams of various types. South Africa’s tailings dams are among the largest in the world in terms of delivered tailings tonnages, plan size and height. Obviously tailings disposal from the mining and industrial sectors in South Africa can have a major impact on the environment and the safety of human life if the dam design and tailings deposition process are not properly controlled. In South Africa there is a growing awareness of the importance of the environment and of the safety of the tailings dams. Catastrophes like the Merriespruit Gold Tailings dam failure in February 1994, where 17 people died and widespread devastation and environmental damage was caused, has sparked the renewal of research into tailings dam stability and safety. The rate of rise of tailings dams has an influence on the safety and stability of a tailings dam. If rate at which a tailings dam is built is too high, the dam may become unstable and be at risk of failure. There are many factors that control the rate of rise of tailings dams that are not very well understood. This research deals with sedimentation and desiccation of gold mine tailings. Sedimentation and desiccation are factors that influence the rate of rise. This research looked at how the gold mine tailings behave when sedimentation and desiccation occur. This was achieved through laboratory experiments, which consisted of column settling tests and drying box tests, and field tests. A model that predicts the behaviour of sedimentation and desiccation of tailings was also analysed. It was found that tailings sedimentation occurs very quickly. It was also found that suctions play an important role during the desiccation of the tailings. / Dissertation (MEng (Geotechnical Engineering))--University of Pretoria, 2007. / Civil Engineering / MEng / unrestricted
29

Analysis of contributions to the PM10 concentration in a gold mine residential village

Ramsuchit, Dhunraj January 2013 (has links)
Main findings Although the data did not allow the inclusion of non-identified or “unknown” sources, allocation of the impact at the receptor point to the identified sources proved possible and useful in comparing individual tailings dams contributions. The No. 4 tailings dam has been identified as one of the major contributors to PM10 concentration at West Village. The average PM10 gravimetric concentration recorded at West Village was 18.4 μg/m3 and the concentration with the light scatter method was 15.4 μg/m3. Black carbon has been identified as significant contributor to overall PM10 mass concentrations with up to 34% in the winter season. Source appointment from receptor-based measurements has not been previously conducted at Driefontein Gold Mine. Source apportionment can make a valuable contribution in attempts to reduce air pollution. At a site where particulate matter is the predominant pollutant from a variety of potential sources, the contributions from the individual sources may be difficult to distinguish especially if the sources fall within a single category type with similar pollutant profiles. It would be useful to ascertain the individual contributions so that the effectiveness of existing control measures can be determined and areas where additional controls may be required can be identified. Too this effect, potential dust sources at and around a gold mine were identified. Samples of the dust sources were collected and analysed for their elemental compositions and abundances. A receptor point in a mine village was selected and equipped with an ESampler PM10 dust monitor as well as an aethalometer, the MicroAeth AE51 (MicroAeth). Monthly receptor samples were collected and analysed for their elemental concentrations. The elemental compositions of the potential sources and the concentrations at the receptor were statistically analysed for 12 periods of a month each to determine the possible contributions to the PM10 concentration at a mine village (West Village, Driefontein Mine, near Carletonville). Main conclusions Operational tailings dams can under, certain conditions contribute the major portion of fallout dust and PM10, even more than dormant tailings dams. / Dissertation (MSc)--University of Pretoria, 2013. / gm2014 / Chemical Engineering / Unrestricted
30

Ore Petrology and Wallrock Alteration Studies at the Lake Shore Gold Mine, Kirkland Lake, Ontario

McInnes, Brent Ian 04 1900 (has links)
<p> The Lake Shore Mine has accounted for over a quarter of the gold produced in the Kirkland Lake camp. Petrography suggests that gold is a later phase in the paragenesis of ore minerals. Sulphides precipitated first followed by tellurides and gold. Wallrock alteration adjacent to the quartz veins was studied by thin section and geochemical analysis. Petrography enabled an alteration facies scheme based on predominant alteration minerals to be established. The alteration assemblages suggest the fluid had a high K and CO2 content, low Na, and reduced S content. Geochemical analysis of these samples confirm petrographic observations and suggests major additions of K2O, SiO2, Rb, Sb and Au to the wallrock, and losses of Na2O, Ba and Zr from the wallrock.</p> / Thesis / Bachelor of Science (BSc)

Page generated in 0.0837 seconds