*Electronic Theses and Dissertations (Masters)

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    The application of process mineralogy to improve gold extraction from Wits tailings
    (2024) Makamu, Sazini
    The extraction of gold from secondary resources such as historical Witwatersrand (Wits) tailings has been vital in extending the life of the South African gold industry. For a long time, Wits gold tailings have been a liability to mining operations due to the cost of the management of tailings dams. If tailings are not adequately managed, they can have long-term negative effects on the environment and human health and safety, with pollutants from effluent and dust emissions possibly being hazardous to humans, animals, and plants. However, due to a decrease in ore grades, the growing drive for zero waste, and improvements in technology, tailings retreatment is now a sustainable form of revenue for gold operations in South Africa. While the Wits gold tailings are characterised by low gold content, there is however, an expectation that this residual gold can be efficiently and economically extracted since gold extraction technologies have improved. However, low gold extraction efficiencies have typically been observed with typical plant operations operating at 40-50% recoveries. Poor liberation is a common postulation on the causes of low gold extraction and slow leaching kinetics. As a result local Wits tailings toll treatment plants apply ultra-fine grinding (P80 -20 µm) to partially liberate the gold and achieve economical gold extraction. However, an alternative hydrometallurgy approach that does not come with the capital and process implication of fine grinding can prove to be more economical. The study aimed to establish the cause of reduced gold extraction in a Wits tailings concentrate followed by the establishment of a hydrometallurgy process route that improves the gold extraction. The aim of the research was achieved through a process mineralogy study of a typical Wits pyrite concentrate sourced from the DRDGold’s Ergo flotation plant. Data from the process mineralogy study was then interpreted to develop a test work program that aimed to improve the gold extraction from Wits pyrite concentrate. The results from the study showed that gold in Wits tailings appears predominantly by way of native gold which can easily leach with cyanide, with a negligible amount of electrum. The locking and reactive gangue minerals in the form of iron sulphides pyrite and pyrrhotite were noted to restrict cyanide access to the gold particle. Furthermore these minerals tend to partially dissolve during cyanidation in an alkaline medium. Three options identified to improve gold extraction included the passivation of iron sulphide mineral facades using an arrangement of pre-oxidation, lead nitrate addition to improve leaching kinetics and reduce cyanide consumption, and leaching at elevated dissolved O₂ concentrations with excess cyanide addition. The application of pre-oxidation (lime + air) with increased dissolved oxygen (DO) and cyanide (CN- ), increased gold extraction to 77% at a decreased retention time of 18 hours, which is 17% higher than gold extraction achieved during cyanidation of the same resource at DRDGold ERGO plant. The addition of lead nitrate did not improve gold extraction but was beneficial in reducing cyanide consumption by 0.13 kg/t.
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    Urban scripting audio-visual forms of storytelling in urban design and planning: the case of two activity streets in Johannesburg
    (2024) Mkhabela, Solam
    South African cities reflect spaces based on Euro-American theories and norms, mapping methods, and design imperatives. At a local level, this imposition’s tool of static diagrams, plans, sections, elevation, and aerials; broader spatial plans with localized frameworks; regulatory plans controlling land use results in spaces hindering socio-economic development, especially for the marginalized, which comprises a predominantly black African and poor cohort. Consequently, current practice must significantly improve a city’s engagement with everyday users. Based on the indicated need, this thesis argues that the first step to effective urban design is accurately ascertaining spatial needs. In responding to current city-making practices that create ineffective spatial outputs, the study introduces Urban Scripting as a novel transdisciplinary and practice-based approach for assessing inhabitable urban locations. Its methodology in city-making processes strategically inserts social narrative to enhance understanding of daily user experiences. In creating accessible ways of exposing urban layer details, the procedures combine Nguni oral tradition (local expertise) with audio-visual (disciplinary knowledge) as a hybrid narrative technique that simultaneously analyzes and produces. Here narrative suggests using story to amplify an evolving discourse unit that writes and communicates spatial imagination. More so, storytelling, framed in and through interaction, finds people and information often missed by conventional mapping and assessment tools, specifically the voices in the ‘twilight zone,’ the space between legal and illegal on-the-ground operations. Transdisciplinary methods structure more critical and empirically on-ground evidence that inductively leads to new ways of thinking and analyzing. Practice-based casework turns space into place, builds an anthology of empirical knowledge to inform city-making methodologies, and shapes appropriate policies supporting subaltern communities. Programmatically and polemically, it explores how a cinematic frame is an inclusive tool within a specific set of urban processes. Ultimately, its enframing application calibrates an empathetic narrative, potentially transforming lives better for an African city in motion. This approach is valuable for practitioners as a firm departure from convention and thrusts Black African knowledge to the forefront, thus acting as a decolonization tool. Tested at two different sites in Johannesburg, Alexandra (formerly a Black dormitory ‘township’) and Orange Grove (once a whites-only area), the approach effectively engaged with spatial users, specifically, the microentrepreneurs whose urban insurgency practiced on the side of the street serves the broader public yet remains unnoticed by spatial practice. Urban Scripting’s methodology better understood the urban spatial challenges and needs at the Johannesburg study sites. For spatial practice site assessment, theory building, and iv practical application, it is an approach that is likely to prove equally effective in communicating bottom-up needs to help imagine and design a fair and democratic city in hundreds of other similar environments in South Africa and indeed, across Africa, where parallel realities exist.
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    Why do people walk on this street?: comparing quantitative and qualitative measures of imageability and their association with pedestrian patterns
    (2024) Msingaphantsi, Mawabo
    Imageability, the quality of a place that makes it distinct, recognisable, and memorable, is traditionally considered to make places pleasant and attractive to pedestrians. The use of primarily qualitative (rather than quantitative) descriptions to discuss the concept of imageability poses a challenge for the application of this concept in physical designs in practice, where designers work with environmental features that have specific dimensions and where they must decide how much of each feature (building height, number of courtyards, number of trees etc.) is necessary to make the environment imageable. There is also wide disagreement in urban design theory and practice about what factors contribute to imageability. Quantitative models attempt to address these challenges by producing operational definitions of imageability with strictly defined variables (factors) that are based on the mathematical relationships between physical environmental features (such as building shape or street length) and the occurrence of imageability. The chief benefit of these models for urban design is their potential use as a means to measure and describe the presence of imageability in a given place. However, the drawback of models is the limited number of verification studies to test their applicability in different contexts. The Ewing model is a street-based statistical model that uses a street audit to describe how imageable a place is from the point of view of a pedestrian on a street. The model identifies eight variables that have a statistically significant correlation (R>0.6) with imageability (Ewing, Clemente, Handy, Brownson, & Winston, 2005). In this study I apply the Ewing model to a low-density environment to measure the imageability of part of Diepkloof (Zone 5), a former black township in Johannesburg, South Africa. I use sketches and qualitative descriptions to validate measurements taken on 30 streets. The purpose of the study is to determine the extent to which environmental features such as imageability can explain pedestrian patterns in a neighbourhood. I tested for correlation between pedestrian activity and imageability and then created a linear regression model to predict pedestrian volume on a given street based on the level of imageability on that street. My conceptual framework, however, demonstrated that imageability has three key aspects (structure, identity and meaning) and that different quantitative models have in-built assumptions that privilege one or more of these aspects and may affect how the resultant measurements should be interpreted. I use mapping to illustrate other potential factors of imageability (as described in the literature and in other models) and argue that these represent conceptual gaps in the Ewing model that should be considered when interpreting the model’s outputs and their correlation to pedestrian patterns. The results of applying the Ewing model in Diepkloof Zone 5 show low levels of imageability, which is consistent with my qualitative assessment of the site, as lower densities reduce the potential for composition because the environment has fewer elements. Bivariate linear regression was found to be an inadequate measure of the correlation between imageability and pedestrian activity. These simple linear regression models had R2 values of less than 0.65 and had many outliers, which suggested that there were factors outside of the model that had a significant effect on pedestrian activity. When multiple regression is used to account for other neighbourhood conditions, correlation increased and the R2 value (which describes the models’ predictive capacity). There are three statistically significant variables (with p-values less than 0.05): street length, street integration and imageability
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    Critically exploring the link between privatization and institutional capacity at the local government level in South Africa
    (2024) Ralane, Hluma Luvo
    This study aims to critically explore the link between privatization and institutional capacity at the local government level in South Africa. The study is presented in a user-friendly manner for a wider readership. The central themes explored by the study are local municipalities and privatization. A discussion of the central themes of this paper evolves in the following way. Firstly, the paper outlines the nature of local government in South Africa dating back from the apartheid epoch to the inception of democracy in 1994. It reflects on the local government sphere which is a collective of local municipalities, analysing the nature and structure of this sphere. In its expedition, it particularly focuses on a Category B municipality from Queenstown Eastern Cape. Surveying the outplay in the link between privatization and the institutional capacity in this municipality through the contracting-out of services, particularly water privatization in that municipality. The reflection on local government is succeeded by the scrutiny of the privatization theoretical framework. The study assesses the root nature of privatization. It investigates its emergence from a global frame of thought, how it has evolved through neoliberalism, and ended up superseding other macro-economic frameworks and being a central policy of governance linked to the institution's capacity. The study further looks at the different frameworks provided by the government to enhance institutional capacity at the local government level, together with the methods and theories that characterize privatization, and the outcomes that underpin it. The scrutiny of the above central themes leads to a broad analysis of case studies from a global realm, regional arena, and local arena. The study utilized both qualitative and quantitative research methods to gather data for the study to complement the former methods the study used an exploratory research design as it was broadly exploring the link between privatization and institutional capacity. It further used semi-structured interviews to substantiate the theoretical findings. Throughout the paper, explicit examples are provided to substantiate all arguments raised.
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    Reusing the urban fabric: adaptive re-use of an abandoned heritage building to explore community empowerment within the Johannesburg CBD's textile industry
    (2024) Soobramoney, Kyle
    The city of Johannesburg has undergone massive transformations since its conception and the discovery of gold that set the city on an exponentially rising trajectory. In the aftermaths of apartheid, many post-industrial buildings are scattered through the city landscape, forgotten, and decaying with accompanying detrimental effects to their surrounding context. This investigation aims to reuse a delipidated heritage building to grow economy through local industry. In the case of this investigation, the relevant industry is the ever-growing textile and secondhand clothing market. This industry is contextually relevant, and the basic design principles of Architectural theory demand a building be responsive to the context to be successful. The hypothesis is that if an industrial function can be retrofitted to dilapidated buildings, then these buildings can be saved and enhance the environment in which it dwells. The textile industry in this case offers a multitude of job opportunities as well as applications in architecture and construction. Traits that could possibly help working class, and female entrepreneurs have a stronger foothold in the city, as industrial labor, and basic job access can become more available to women that may be unemployed and unskilled. Design methodologies such as adaptive re-use and symbiotic architecture are aimed to be implemented to endorse an architecture that is feasible for abandoned heritage buildings, concurrently these methodologies are intended to be explored through the textile industry. Architecture that is intended to be easy and cheap to assemble; architecture that can move, grow and change based on the needs of the user while preserving the identity of the building and at the same time creating a new one for a new generation. The end goal is to create a mixed use closed loop self-sustaining building that programmatically focuses on the education and economic components of the context as well as enhances community development in the city. The investigation aims to understand (through experimentation) if an architecture can be applied to the delipidating heritage typology as an effort to reuse space and the preserve character, memory, and diversity in a way that the generation of today will be excited to be in an old building. The city has become a hub for informal traders and entrepreneurs, a social and economic melting pot. There is an opportunity for existing industries to revitalize fragmented infrastructure to add to the mixture.
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    Architecture as mnemonic experiencing past, present, and future narratives in a Johannesburg cultural complex
    (2024) Segal, Yehuda
    Memory is transient, it comes and it goes. It is a passing remembrance of a past time, person or place. Memory is the experience we store in our minds to recall at a future time and date. It is the friends we make on the first day of school, our childhood holidays, or beach sand between our toes. Memory is also stored in books, visuals, art, and the internet. It is the long-gone monarch in a painting, the photographs and videos of historical events that record a past time and people. And so, memory is architecture- or, simply, space. Spatial recall- the ability to remember a space or place, directions from point A to point B, is the reason we find our way when lost. The architecture of memory is related to that of structures, buildings and spaces that serve to record or preserve a past event or person, yet also the landmark that guides us. It is a museum, memorial, triumphal arch and even a religious or cultural space. It is also the old as opposed, or in harmony with, the new. Architecture as mnemonic is relatable to other aspects and devices with mnemonic value. Memory is therefore an important aspect of archi - tecture and the built world. Not only do we remember through spatial interactions, we also experience spaces which lead to us creating new memories.
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    Manufacturing imaginaries: a catalyst for reimagining Marshalltown
    (2024) O’Donovan, Gabriel Storm
    The inner city of Johannesburg oscillates between images of a vibrant city full of possibilities, and a dystopian city that has fallen into disrepair - illustrating the profound complexities of the city and its resilience, where spaces of dystopian desolation lie adjacent to dynamic spaces of ambition and hope. Since Johannesburg’s establishment various regimes of representation have sought to create a city in their image (Matsipa, 2014) – from visions of Johannesburg as a temporary mining camp with the sole purpose of extracting wealth, to the modernist images of a “New York in Africa” (Chipkin, 2008). This project explores how visions from a past epoch can be re-imagined and questions the role of the architect in facilitating new urban transformations. This research report investigates the accumulated archive of abandoned buildings in the inner city and presents an architectural intervention that acts as a piece of urban infrastructure – facilitating the reinterpretation of these neglected structures. It draws inspiration from current examples of ad hoc spatial interventions that challenge the notions of permanent and purpose-made architecture. The site forms part of an abandoned city block in Marshalltown, Johannesburg. This city block serves as symbol of urban decay and neglect, portraying feelings of desolation and abandonment (Bruwer, 2002) – making it the ideal site for the proposed architectural intervention as well as a source of inspiration.
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    Cross-border pollination: incubation hub for urban farming in Yeoville
    (2024) Kubanza, Nzoli Gloria
    Yeoville holds the reputation as an Afro-migrantcentric suburb in Johannesburg (ABED, 2019), with each dispossessed body desiring to keep their cultures alive. This has created social boundaries between South Africans and other African nationalities in the urban landscape. The burning of Yeoville Market is the physical manifestation of growing tension in the community. Gambela (BÉNIT-GBAFFOU, 2019) (known by the neighbourhood) provides migrant women from the diaspora the opportunity to respond to the economic crisis they face in their home country. The enclosed market sphere encourages cultural exchange and interaction by eating, processing, and selling food from home. For migrants living in Yeoville, food is not only a source of nutrients but a tool to transmit culture. Thus, the burning of the market signifies the resistance of the community to integrate. The thesis will follow the Congolese women in the Yeoville market who frequently encounter borders, traveling with various products including cassava. The traders use cassava to transgress the misconceptions of a patriarchal stereotype of an African housewife, simultaneously ensuring household survival. Cassava holds a cultural significance to the West African women as the method of processing cassava requires the knowledge of the native women that have passed down from one generation to another, perfected through time and across borders (Christina Emery, 2021). The importance of the plant not only lies in its mobility but its functional characteristics of promoting harmony, encouraging collaboration, and a medium in which information is transferred (Christina Emery, 2021). In asking the question “how can cassava be used to mend the fragmented community of Yeoville” this thesis will be using cassava as a framework to explore themes of, mobility, boundary, and identity. Re-introducing the market to the community as an agricultural hub. The architectural intervention will re-interpret the market as a space that transmits and preserves culture. The project aims to mediate the fragmented communities of Yeoville using food to educate, generate social spaces, and food works to encourage community involvement.
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    Unravelling nature: integrating architecture and nature
    (2024) Katete, Lungo
    The ability to bring to life what is created in one’s mind, is perhaps the most remarkable feat of human kind. Without the ability to imagine, innovation ceases to exist, resulting in the overall demise of evolution itself. We exist in a time during which the destruction of nature and its essential continues to expand as quickly as nature diminishes right before our eyes. Our environment is populated with built structures and design artefacts, but very few of these rattle the domain of intellect in a way that provokes cultural reorientation. Persuaded by nature’s grand design, this research document proposes a new approach to architecture, through model development and alternative/natural material exploration. It aims to scrutinise the potential of a new way to create architecture through nature’s lens, encompassing formation that consolidates maximal performance and minimal resources through local material variations. In this approach, architecture will be viewed through the lens that is nature, promoting the consolidation of form, materiality and structure. This will be done by exploring aspects such as form development, material analysis and fabrication, allowing for the utilisation of materials found naturally occurring in nature. Materiality precedes form making, allowing for an approach that is structured based on the material properties as a function of structural and environmental performance. This approach shall integrate material properties as a prospective driver of the form generating process, it shall establish how such processes contribute to a novel way of generating, dispensing and depositing material form. In an environment populated primarily by built structures, it is essential that we take into consideration how we can integrate nature’s grand design in the evolution of the design fabric and the built environment process, for without the ability to imagine, innovation ceases to exist.
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    To burn or not to burn: an approach to control waste in our society highlighting the Relationship between energy, recycling and communities
    (2024) Kabongo, Benedictte
    The capacity of South Africa and other developing countries is as minimal. On the other hand, the growing trends - population growth, industrialization, and economic growth- in modern-day society have improved human wellness. As a result, when resource consumption rises, so as solid waste. However, in developing countries, the generation of waste per capita is the lover compared to developed countries; the main challenge is the capacity to handle it effectively. Moreover, efficiently landfill, recycle and reuse. The resource consumption model in developing countries is linear, meaning that processing, producing, using, and discarding products to nature harms the environment through the emission of greenhouse gas, the pollution of land and water resource, and boost climate effect. In the last decade, solid waste management has improved technologically and operationally and responds to environmental concerns; its focus is on the end-stage solutions, focusing on the reduction of waste rather than sustainability, whose core focus is the prevention of waste. South Africa’s approach regarding solid waste is to push waste up towards minimal production, reuse, and recycling through comprehensive producer responsibility and economic instruments This research focuses on the factors impacting solid waste management in South Africa and will put forward realistic avenues for using solid waste as a resource. In addition, it will help find successful initiatives highlighting inclusive planning and management of those facilities. Finally, this finds approaches for the private sector, the government, and the community to link service and value chains in sustainable solid waste management. For example, it adopts practices that divert waste from landfills, formalizes reclaimers or waste pickers, initiates waste-to-energy technologies, and encourages recycling at all waste cycle stages.
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    A bathhouse in Cyrildene - a phenomenological approach to the design of a bathhouse in Johannesburg
    (2021) Kow, Alan
    In Johannesburg, there is a lack of global bathhouse typologies. They either don’t exist or are in a form which caters to a niche subculture. Bathhouse culture has been around for hundreds of years and many people around the world take advantage of it as a form of communal bonding, relaxation and general hygiene. In addition to this, when done correctly, it has the effect of stripping away of social class and distinction as well as providing a safe and entertaining environment for those within its walls. This study aims to bring my personal experience of an East-Asian bathhouse into Cyrildene, a predominantly Chinese neighbourhood, that is slowly losing its cultural identity. Building on existing data on historic bathhouses from around the world, it asks: How can the concept of phenomenology be used to guide the design of an Asian style bathhouse in order to enhance the Asian/Chinese cultural experience and help in the revitalisation of Derrick street as a distinct cultural hub In Johannesburg? The main methodologies that will be used in this report will be from literature reviews on historical analysis of bathhouses around the world but more specifically in Eastern Asia. One on one interviews with the residents and shop owners living in Cyrildene as well as the owner/s of a spa. Observations based on mapping and photography will also be employed. The last will be the use of auto-ethnographic data from my own experiences. The main hypothesis of the report will be seeing if the bathhouse typology through the use of a variety of different programs that range from bathing to eating to sleeping in addition to the application of architectural phenomenological theories helps make it suitable for Cyrildene and thereby revitalise and strengthen the areas existing cultural identity.