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  • 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.
381

The exploration of appraising internal controls to detect procurement fraud during the tender stage at mines

Venter, Jan Willem Nicolaas 02 1900 (has links)
Text in English / Procurement fraud is an enormous problem and the South African news is perforated with reports of this illicit act. Procurement fraud occurs in all the phases of the procurement cycle, but this illicit act is mostly committed during the tender phase. Business does not see procurement fraud as a crime and therefor this crime is committed due to non-existent internal controls and processes to assess the adequacy of these controls. The purpose of the research was to highlight that procurement fraud occurs when internal controls are being bypassed or if an entity has an ineffective internal control system. The researcher studied the appraising of internal controls to understand the role it plays in detecting, preventing and investigating procurement fraud, specifically during the tender phase. The research design utilised was a qualitative research approach and an empirical design plan or strategy, to obtain the information. The researcher opted for this design to obtain information from literature and information from individuals in appraising internal controls. This ensured a comprehensive data gathering process. The goal of this research was to provide practical recommendations to assist investigators in private and public sectors with investigations into procurement fraud during a tender. / Police Practice / M. Tech. (Forensic Investigation)
382

Modelling, simulation and optimisation of a crushing plant

Ndhlala, Blessing 07 1900 (has links)
African copper PLC’s flagship is the copper producing Mowana mine located 129 km from Francistown in the North-Eastern part of the Republic of Botswana. The processing operation at Mowana is a standard flotation plant designed to produce copper concentrates from oxide, supergene, and sulphide ores. The expected average output of 16.2 tons per hour of copper concentrates has never been attained since plant commissioning. The major bottleneck has been established to be located around the crushing circuit of the Mowana production chain. The major hypotheses of this research are that performance in a crushing plant is adversely influenced by moderate and discrete changes in the process. The ultimate objective is to develop a dynamic process simulator, administered in Simulink/MATLAB® background, for application in the design of a control model utilising two crusher variables and a self-tuning control algorithm. In this research work, a process model describing the dynamic operation of an Osborn 57S gyrasphere cone crusher is investigated. Modelling of the Mowana crushing circuit is carried out by combining the steady-state and dynamic components of the crushing equipment in the Simulink/Matlab® environment. Eccentric speed (ES) and closed-side setting (CSS) are amongst the important inputs to the models. The rest of the inputs (crusher power, crusher cavity level, federate, pulley diameters, liner wear measurement, number of teeth of the pinion and bevel gear) are extracted from the data collected across the Mowana mine crushing circuit. While it has been demonstrated that the crusher CSS is the most influential controllable parameter, it has also been demonstrated that crusher capacity and power can be used effectively to optimise the circuit. The use of crushing power and cavity level control is suitable for the crushing circuit since the crushers are running on a constant ES and the CSS is set and reset manually. The outcome of the study presents an insight into the optimization of the Mowana mine crushing circuit through the design of a self-tuning controller for the cone crusher and for prototyping, parameters of a PID controller were determined in the Simulink/MATLAB® environment. The simulation involved the optimisation of the control model as a function of the cavity level of and the power drawn by the cone crusher. A self-tuning control algorithm at PLC and SCADA level of control was then tested. This formed the simulations and training platform. The outcome of the simulations carried out in this research needs to be validated against the real Mowana crushing process control upgrade. This will then inform the modifications and recommended crusher motor resizing exercise to be implemented. / Electrical and Mining Engineering / M. Tech. (Engineering: Electrical)
383

Data acquisition system for pilot mill

Molepo, Isaih Kgabe 04 1900 (has links)
This dissertation describes the development, design, implementation and evaluation of a data acquisition system, with the main aim of using it for data collection on a laboratory pilot ball mill. An open-source prototype hardware platform was utilised in the implementation of the data acquisition function, however, with limitations. An analogue signal conditioning card has been successfully developed to interface the analogue signals to the dual domain ADC module. Model-based software development was used to design and develop the algorithms to control the DAS acquisition process, but with limited capabilities. A GUI application has been developed and used for the collection and storage of the raw data on the host system. The DAS prototype was calibrated and collected data successfully through all the channels; however, the input signal bandwidth was limited to 2Hz. / Electrical and Mining Engineering / M. Tech. (Electrical Engineering)
384

Investigating climate change intervention strategies in opencast mining contracting and plant hire companies: a case of mutual construction company group of companies, South Africa

Matangira, Peace Aaron 06 1900 (has links)
Climate change has come to be understood as a deleterious phenomenon, which threatens business, society and ecological systems, thus making it imperative to understand its impact on human, social and economic activities as well as the impact of these activities on climate change. Against this background, this research sought to determine climate change intervention strategies in the mining supply chain in general, specifically focussing on opencast mining contracting and plant hire companies’ practices. This focus on the mining industry was driven by its importance in South Africa and globally, despite its significant direct and indirect contribution to climatic changes. The mixed-methods multiple case study focused on the climate change management of the Mutual Construction Company Group of Companies (MCCGC), an open cast toll mining firm and equipment supplier. Limited to two sites, Pilanesberg Platinum Mines (PPM) and Tharisa Minerals (Tharisa) Mines, the researcher gathered data through interviews, questionnaires, observations and document review. Data was analysed through deductive content analysis. The research made three major findings: (i) the MCCGC, like its principals PPM and Tharisa, does not have an explicit climate change management strategy. Instead, climate change is managed indirectly through implicit strategies seeking to manage environment, health and safety concerns of the mines, (ii) as a contractor, the MCCGC has had to adopt PPM and Tharisa’s implicit approach to climate change management strategies to meet contractual obligations, instead of an explicit approach and, (iii) the MCCGC and its principals’ commitment to environment, health and safety management, and implicitly climate change management, is not mere rhetoric but is being put into practice. The research concluded that MCCGC’s lack of expressed climate change management intentions and practices exposed the firm to climate change risks, most notably financial risks and reputation risks. Financial risks arise from possible ex post climate change liability. In addition, MCCGC is risking its contract tenures, particularly if the two mines change ownership and the new owners insist on an explicit rather than implied climate change strategy with all its suppliers. Reputational risks arise from the possible failure to attract new clientele and investors who may perceive MCCGC as a risky partner, due to an inept climate change intervention strategy / College of Agriculture and Environmental Sciences / M. Sc. (Environmental Management)
385

The relationship between graduate employability and work performance in the mining industry in South Africa

Breedt, M. 06 1900 (has links)
In a rapid changing environment mining companies have to change the way in which they do business, while employees have to manage their careers and ensure they are multi-skilled. Organisations are looking to employ individuals who are career driven, highly adaptable and flexible and display the necessary employability skills. The main purpose of this study was to determine if any relationship exists between the different factors of graduate employability and work performance in the mining industry in South Africa. A cross-sectional quantitative research approach was followed. A simple random sample was drawn from graduate male and female employees between the ages of 18 – 30 years with any post-matric qualification employed in the mining industry in South Africa. Through the process of exploratory factor analysis, six graduate employability factors and four work performance factors were identified. The graduate employability factors included career self-management drive, cultural competence, career resilience, emotional literacy, career literacy and self-efficacy. The work performance factors included the supervisor role, employee role, recognition and organisation support. Correlation and regression analyses were conducted. The results indicated a relationship between graduate employability and work performance. Strong, positive correlations were found between graduate employability and work performance with career self-management drive being the strongest predictor of work performance. Recommendations for the mining industry focused on how employability could be enhanced to improve work performance. / Human Resource Management / M. Com. (Human Resource Management)
386

An evaluation framework for virtual reality safety training systems in the South African Mining Industry

Van Wyk, Etienne Anton 02 1900 (has links)
The mining industry in South Africa contributes significantly to the national economy. Despite stringent safety legislation, mining accidents cause numerous fatalities and injuries. Inadequate or insufficient training is often cited as a root cause of accidents. Conventional class-based safety training has not reduced the incidence of accidents significantly. By contrast, virtual reality training tools can provide simulated exposure to real-world working conditions without the associated risks. This study describes the application of design-based research (DBR) in the design and development of two desktop virtual reality (VR) systems for safety training in the South African mining industry. The results of a usability context analysis were applied in the design of a VR prototype on generic hazards recognition and rectification, which was used and evaluated at South Africa‘s largest platinum mine site. A case study was conducted to investigate the causes and occurrences of falls of ground, which resulted in the design and development of a second VR prototype focusing on identifying and addressing underground geological conditions. DBR was also used in the generation of an evaluation framework for evaluating VR training systems, namely the Desktop VR Evaluation Framework (DEVREF), which is the major deliverable of the research. DEVREF can make a major contribution to the domain of e-training in mines and is transferable and customisable beyond its initial application. The process flow of the research thus moved beyond merely providing a solution to a complex real-world problem and became a classic DBR study with dual outcomes, namely a practical real-world solution in the form of two VR training systems and a theoretical contribution in the form of the DEVREF evaluation framework. DEVREF evaluates the design of desktop VR training systems in the categories of instructional design, usability, VR systems design, and context-specific criteria for mining. The use of DEVREF is demonstrated by reporting the application of its criteria in evaluating the two VR training systems. Heuristic evaluation, end-user surveys, and interviews were used as evaluation methods. A third contribution is methodological, in that this work proposes a new DBR process model and an interaction design lifecycle model suitable for VR training systems. / Computing / D. Phil. (Information Systems)
387

Impacts des activités minières sur les écosystèmes forestiers au Katanga, République Démocratique du Congo

Kabulu Djibu, Jean-Pierre 26 September 2011 (has links)
En dépit de ses ressources naturelles, le Katanga connaît une déforestation inquiétante durant ces dernières années. Avec 157.525 km², la forêt au Katanga ne recouvre plus que moins de 4% environ du territoire. Les forêts sont considérablement en régression, soit un taux de déforestation annuelle d’environ -0,20%. Ce processus s’est récemment accéléré, tout particulièrement dans les zones minières et dans les hinterlands de tous les grands centres urbains, suite à une forte pression démographique et aux activités minières qui en résultent. Le paysage forestier est donc dynamique et change, en composition et en configuration spatiale au cours du temps. L’objectif principal de cette étude était d’évaluer l’état de la fragmentation de la forêt au Katanga, en utilisant les techniques et méthodes de l‘écologie du paysage. Un accent particulier a été mis sur l’impact des activités minières sur les paysages forestiers et sur l’exploitation artisanale de bois énergie. Cette quantification de l’état de la fragmentation peut être utile d’une part aux services publics de l'État congolais pour évaluer de manière différenciée les processus de déforestation et la vulnérabilité du paysage, et d’en tirer les conséquences opérationnelles. D’autre part elle est utile aux services de recherche et de conservation pour prendre en considération les facteurs de risque de la déforestation au côté des autres (vent, pluie, érosion, crues, ruissellement, etc.). Dans la présente étude, nous nous sommes basés sur l’hypothèse selon laquelle les actions anthropiques sont les principales causes de la fragmentation de l’habitat. <p><p>Les résultats ont montré que l’exploitation minière et la croissance démographique sont deux facteurs de la déforestation, considérés comme les paramètres principaux du processus de changement du paysage au Katanga. L’analyse spatiale, faite grâce à la cartographie et aux systèmes d’information géographique, a permis de faire le calcul d’indices de composition et de configuration du paysage afin d’analyser la structure spatiale des forêts. La structure a été ensuite modélisée pour évaluer les impacts de concessions, des routes et des sites miniers sur la forêt. En fonction de résultats obtenus, on constate que les forêts du Katanga subissent une pression anthropique assez forte et la tendance générale de la fragmentation des forêts est inquiétante. Les habitats forestiers sont entrain d’être transformés en formations savanicoles. Les activités minières ont un impact défavorable sur les forêts de la province. La présence des plusieurs compagnies minières a favorisé l'augmentation des sites miniers et la densification du réseau routier. <p> / Doctorat en Sciences / info:eu-repo/semantics/nonPublished
388

Marikana : taking a subaltern sphere of politics seriously

Naicker, Camalita January 2014 (has links)
This thesis aims to open up the realm of what counts as political in the context of the Marikana strikes and subsequent massacre. It does primarily by taking into account the social, political and cultural context of Mpondo workers on the mines. Many narrow Marxist and liberal frameworks have circumscribed the conception of the ‘modern’ and the ‘political’ so much so that political organisation which falls outside of this conceptualisation is often regarded as ‘backward’ or ‘archaic’. It will provide an examination of the history, culture and custom of men, who have, for almost a hundred years migrated back and forth between South African mines and Mpondoland. This not only reveals differing modes of organising and engaging in political action, but also that the praxis of democracy takes many forms, some of which are different and opposed to what counts as democratic in Western liberal democracy. By considering what I argue, following some of the insights from the Subaltern Studies collective in India, to be a subaltern sphere of politics and history, it is possible to better understand the way workers organised and acted. The thesis also argues that most labour and nationalist historiography has been silent on the political contributions of women because of how Marxist/liberal analysis frames struggles through disciplined notions of work and resistance. Rather than objectifying workers as representatives of a homogenous and universal class of people devoid of context, the thesis has linked ‘the worker’ to the community from which s/he comes and community specific struggles, which are supported and sustained, often, by the parallel struggles of women in the community.
389

An integrated model of milling and flotation for the optimal recovery of sulphide ores at the Kansanshi mine

Lusambo, Martin 11 1900 (has links)
Kansanshi mine sulphide ore circuit did not achieve target flotation recovery in 2016, hence it was deemed necessary to carry out a research aimed at optimizing this circuit. The objective of the research was to optimise the Kansanshi milling and flotation circuit processing a copper sulphide ore. In line with this, samples were obtained around the circuit and processed in the laboratory for moisture content, slurry concentration, particle size distribution, and flotation response. This information was then used to build a computer-based model of the Kansanshi milling and flotation circuit. This was done in MODSIM®, a software package specialising in the design and simulation of mineral processing operations. After careful appraisal, appropriate models were selected for the semi autogenous grinding (SAG) and ball mills, SAG mill discharge screen, hydrocyclones, pebble crusher, and the flotation cells. The calibrated model was then used to simulate the effects of key operating parameters on flotation recovery. Analysis using the attainable region technique revealed that the SAG mill feed-rate should be adjusted from 1719 tph to 2090 tph. This would lead to a better utilisation of the pebble crusher that can process 358 tph of pebbles from the current 198 tph. From the simulation work, it was established that rougher flotation recovery can be improved from the current 80.0 % to 82.3 %. The technoeconomic benefits of the proposition are yet to be investigated. Findings from the research concluded that the milling circuit optimum operating parameter; which generated a final product falling predominantly in the range - 150 +38 μm were SAG and ball mills conditions of ball sizes 200 and 40mm respectively, ball mill ball filling 32% and rotational speed between 75 and 80% for both SAG and ball mills. The optimum hydrocyclone feed slurry concentration was found to be 62% solids. Additionally, the SAG mill discharge screen aperture size of 6 mm was the optimum. It must be noted that slurry concentration did not show any impact on both the SAG and ball mills performance. The SAG mill ball filling did not show any significant improvement on performance. / College of Engineering, Science and Technology / M. Tech. (Chemical Engineering)
390

The experiences, challenges and coping strategies of women residing around the mining communities : the case of Driekop community, Limpopo Province, South Africa

Lekwadu, Maelane Irene 31 July 2020 (has links)
The plight of women who reside around the mining communities has not received the necessary attention from a research perspective. This concern prompted the researcher to compose a qualitative research aimed at exploring the experiences and challenges faced by these women. This was a case study research which was conducted among women who reside around the Driekop mining community in Limpopo province and designed from exploratory, descriptive, contextual and phenomenological in designs. The study was guided by the two theories: the feminist theory and the coping theory of Lazarus and Folkman. Relevant research ethical principles were upheld during the plenary phase wherein the research proposal was subjected to review by the Higher Degrees Committee of the UNISA’s Social Work Departmental Research and Ethics Committee and throughout the duration of the study. The data which was collected through the semi-structured interviews was analysed using Braun and Clarke’s six steps of data analysis, gave rise to several experiences and challenges which are presented in a form of nine themes and 13 subthemes. In striving to assure research quality, Guba and Lincoln’s trustworthiness principles were adopted. Some conclusions are drawn from the process of qualitative research as an approach adopted to guide the study as well as the findings based on the collected and analysed data. Based on the conclusions of the research process and the research findings, the reader’s attention is drawn to some recommendations which are proposed to inform practice, training and policy development. / Social Work / M.A. (Social Work)

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