Monthly Archives: January 2017

Mine Dust- Implications, Detection and Management

Mine Dust- Implications, Detection and Management

Dust consists of particles in the atmosphere that come from various sources such as soil, dust lifted by weather, volcanic eruptions, and pollution. Although there are numerous natural and anthropogenic sources of atmospheric particulates, mining operations pose the greatest potential risk to human health and the environment. A major problem, especially in the arid and semi-arid areas of Africa, appears to be the contamination by dust fallout from mining operations, from flotation tailing ponds and from smelters.
Dust and aerosol emissions associated with mining operations are commonly associated with significantly elevated levels of hazardous contaminants and are a source of occupational health hazard through direct exposure via inhalation, ingestion and other contamination routes. The changing nature of dust prevalence has led to increased amounts of ultrafine atmospheric particulates with varying elemental compositions. Their subsequent toxicity is also subject to modification. The current work will characterise the changing composition of dust particulates in order to review the present classification system for dusts, using a case study of a fine and ultra-fine process stream coal material generated from a South African colliery.
Rahul Ram
Postdoctoral Fellow
“Be the change you want to see in the world” – Mahatma Ghandi
“Everybody is a genius. But if you judge a fish, by its ability to climb a tree, it will forever live its life believing it is stupid” – Albert Einstein

The Development of an Integrated Approach for Acid Rock Drainage (ARD) Prediction from Waste Rock
World-wide, acid rock drainage (ARD) is one of the largest environmental challenges facing locations with current or previously active mining activities. Formed from the exposure of sulphide minerals to both water and air, and catalysed by naturally occurring iron- and sulphur-oxidizing micro-organisms, ARD is predominantly associated with the mining of sulphidic ores. The effective management of this pollution requires accurate characterisation and prediction of the potential for long term ARD generation.
The aim of this project is to improve ARD characterisation and prediction through the development of an integrated protocol to assess ARD generation. In conjunction with standard ARD tests, the development of improved test methodologies will be used to obtain more reliable estimates for the rates ARD generation at the laboratory-scale under both chemical and microbially-mediated conditions. Integration of these results with a detailed mineralogical and geochemical study of the mine waste will enable a better understanding of the potential for pollution formation. Refinement of a simple mass transport model with results from the aforementioned laboratory-scale tests, and validated with mine-site field tests, will allow for the more reliable prediction of ARD generation.
Alex Opitz
PhD Chemical Engineering
Alexander holds an undergraduate and masters degrees in Chemical Engineering, and is currently completing his PhD in the characterisation and prediction of ARD risks from mine wastes. He has seven years research experience working on industry-related projects across multi-disciplinary fields including mineral leaching, bioprocess engineering and mineral geochemistry.

Characterizing the Environmental Risk Potential of South African Coal Processing Waste
The processing of coal to meet the consumers’ specifications produces large volumes of coal waste that impose environmental risks including water contamination, mainly due to acid rock drainage (ARD) and the subsequent mobilization of metals and salts. Another adverse impact is air pollution from spontaneous combustion of coal processing wastes disposed in dumps. The environmental impacts are related to geochemical and physical compositions of the waste.
Previous work at University of Cape Town to characterise the potential environmental risks of the waste was challenged by inadequate characterisation techniques and insufficient evaluation tools. This project aims to optimise the toolbox for characterising the potential environmental risks associated with coal waste through enhancing, validating and evaluating mineralogical, elemental, geochemical ARD and metal risk assessment tools. The characterisation will be done at laboratory scale on a number of coarse – fine coal wastes from different coal fields and operations in South Africa. The optimised characterisation toolbox will provide reliable data for assessment of human health and environmental risk potential of coal processing wastes. Furthermore, the data is useful in the justification and implementation of environmental impact mitigation measures and also providing a basis for value recovery of these wastes.
Annah Moyo
MSc Chemical Engineering
I am an individual who is not satisfied by mediocre when excellence is there, therefore I made it an obligation to do my best to achieve excellence. If we all do our best with sustainability and development as the set goals then the world will be a better place!!

Minerals To Metals Symposium 2016

LEAD Technologies Inc. V1.01

Dust Monitoring Equipment – providing equipment, services and training in dust fallout management to the mining industry.

 

 

Impact of Mine Waste on the Environment

The Impact of Mine Waste on the Environment and Community Quality of Life: A Case Study Investigation of the impacts and conflicts associated with Coal Mining in the Mpumalanga Province, South Africa

Coal is one of the world’s most used resources and the main energy source in South Africa. However, coal-based power generation industries produce large tonnages of solid waste which pose a significant and irreversible risk to the surrounding environment, and frequently also represent a long-term economic burden and loss of valuable resources. The current emphasis on land disposal and end-of-pipe rehabilitation and reclamation of mine waste by the mining industry has done little to improve its reputation or relieve the continued tensions between mining operations and surrounding communities. The aim of the project is to investigate the relationship between mine waste, environmental degradation and community quality of life to develop a more detailed understanding of the inter-relationship between mine waste, environmental degradation and community impacts, in terms of health and livelihoods. The knowledge and evidence generated is expected to facilitate the development and implementation of integrated and sustainable approaches to the management of mine waste in the South African context.
Bonisile Shongwe
MPhil in Sustainable Mineral Development
”Until purpose is realized, life is meaningless”
Bonisile has development at heart; her work focuses on enterprise development and other livelihood issues with a strong emphasis on empowering rural people and addressing poverty. The Swazi born introvert keeps a small circle of friends, loves family, and enjoys travelling and sport.

The impacts and conflicts associated with waste generated by gold mining in South Africa, with specific emphasis on heavy metal contamination – a case study of Davidsonville (Roodepoort)
Large amounts of gold tailings dams were produced in Witwatersrand area which covers enormous densely populated areas. Often the gold tailings dams contain elevated levels of uranium and other toxic heavy metals that pose a health risk to communities. A lot of newspaper articles and documentaries have emerged where society has associated their health problems to mine waste. Therefore, the aim of the research is to determine the impacts and conflicts associated with gold mine waste, with specific emphasis on heavy metal contamination. The aim will be achieved by, (i) conducting a temporal analysis of incidents of environmental pollution by gold mining with specific emphasis to heavy metals, sources and origins and impacts that this has had on surrounding communities and other activities in the area and the actions taken/repercussions; (ii) establishing current perceptions and understandings amongst the Davidsonville community, the implications that this may/does have on their quality of life and resilience, as well as their legal rights; (iii) analysing the extent of which current community concerns are/have been addressed by the mining industry and/or government, and are supported by scientific evidence and information; and (iv) identifying any gaps and shortcomings with regards to (ii) and make recommendations accordingly.
Phumzile Nwaila
MPhil in Sustainable Mineral Development
Versatile, GIS analyst and Environmental Scientist with multi-disciplinary experience in GIS, Office Administration, Environmental due diligence and Project Management. I hold a BSc in Geology and Geography (UJ); BSc honours degree in Geography (UJ); and currently busy with an MPhil degree in Sustainable Mineral Resource Development (UCT).

Assessment of pollution in the Munkukungwe stream after the closure of the Bwana Mkubwa Mine
Water pollution induced by mining activities is the major environmental challenges on the Zambian Copperbelt. The study was conducted to investigate the pollution situation in Munkulungwe stream located on the Copperbelt. Water samples from four sampling points on Munkulungwe stream near Bwana Mkubwa Mine were analyzed to assess the pollution load. The study assessed the variation of Physical parameters, Heavy Metals and Macro Invertebrates of the stream. Physical parameters and concentration of heavy metals in water samples were determined. pH and Total Dissolved Solids were found to be within the acceptable limits of the Zambia Bureau of Standards (ZABS) at all sampling points. All sampling points recorded high turbidity values above the acceptable limits, while Dissolved Oxygen was below the acceptable limit. Cu was within the acceptable limits while Co, Pb, Fe and Mn were above the acceptable limits. Macro Invertebrates sensitive to pollution were not found in the stream and the average stream rating from the biotic index score was fair. The Results determined, show that the water quality of Munkulungwe stream is polluted. It is recommended that close monitoring of the stream be done.
Lee Mudenda
MPhil in Sustainable Mineral Development
Lee Mudenda is a post graduate student at the University of Cape Town. He enjoys spending time out with his wife Precious, watching football and educating the community on the benefit of environmental stewardship. Grateful for an amazing group of friends that have had a positive impact in his life.

Minerals to Metals Symposium 2016

minerundergroundsafetyprecariousposition1022

Dust Monitoring Equipment – providing equipment, services and training in dust fallout management to the mining industry.

Leaching of rare earth elements

Modelling in-situ leaching of rare earth elements

As the grades of ore, containing precious metals, decline leaching can under certain circumstances present a potentially more economically viable and environmentally friendly process option compared with traditional pyro-metallurgical processes.
As experimental investigations of leaching processes are often time consuming and lack scalability, the development of models to simulate these processes has become of increasing importance. However, as the modelling of leaching systems has been approached from various perspectives, there has been an inconsistent approach to their calibration and validation. This has called into question their reliability in predicting full scale leaching operations. Further systematic modelling investigations are therefore required to address these shortcomings.
As models should always be calibrated and validated against experimental data a case study is required. With the demand for Rare Earth Elements (REEs) rising due to their increasingly ubiquitous use in technology, coupled with the fact that they have not been extensively modelled, extracting REEs using in-situ leaching was chosen as a case study.
Nicole Uys
MSc Chemical Engineering
Completed a BSc (Hons) in Chem Eng (2014), a Postgraduate Diploma in Management, specialising in Entrepreneurship (2015) and currently working towards a MSc within MtM at UCT. Passionate about renewable energy, water purification and waste minimisation and would like to identify new opportunities by exploring the lifecycles of materials from an engineering and entrepreneurship perspective

The influence of diffusion pathways on the solution potential in mineral leach systems
High grade ores resources continue to decline and therefore the mineral processing industry is compelled to process lower grade ore resources which are metallurgically more complex. The processing of lower grade ores necessitates the use of less energy intensive processes in order make extraction economically viable. Heap leaching gained popularity as it is most applicable to the leaching of lower grade ores as it only requires size reduction to relatively coarse particle size, typically in the range of 12 – 25 mm, and is resultantly less energy intensive.
However, heap leaching is still characterized by slow leaching times and low recoveries, which have been linked to using these coarser particle sizes whereby desired mineral grains may not be fully liberated. This is due to that leaching occurs on the surface of surface-exposed or subsurface mineral grains exposed to the lixiviant via cracks/ pores induced during crushing. Once the cracks/pores are fully saturated with solution, dissolved reagents n diffuse through to the mineral surface and products out to the bulk solution, resulting in concentration profiles within the pores. Therefore, a fundamental and experimental investigative study was undertaken in order to elucidate the extent to which concentration profiles within diffusion cracks/pores affect the leaching of encapsulated mineral grains.
Buhle Manana
MSc Chemical Engineering
“I am the master of my fate, I am the captain of my soul” – William Ernest Henley (Invictus)

Dry processing: Developing innovative technologies for improved sustainability in mining
Due to current technologies being exploited in the mining industry, access to high grade ores is becoming difficult due to the depths of mining shafts. As a result, most ores that are being mined currently are low grade ores or complex ores. Ore processing is an energy intensive process; energy intensity is increased when processing low grade ores or high grade complex ores in order to attain desired liberation of valuable minerals. For most ores both low grade and high grade ores, grinding is required to expose the surface area of valuable minerals. Conventional mills (tumbling mills) are energy intensive when it comes to grinding and with the global energy crisis, the use of tumbling mills is not sustainable.
The project aims to investigate the use of a high pressure grinding roll (HPGR) followed by air classifiers for the processing of kimberlite and platinum ores; the overall objective of the project is to save comminution energy, save water in comminution and use the air classifier to separate clay minerals and find the economic value of the clay minerals. Clay minerals are problematic in minerals processing as their undesirable effects are observed in comminution through to tailings dams’ construction.
Gilbert Ncube
MSc Chemical Engineering
“Courage is not something that you already have that makes you brave when the tough times start. Courage is what you earn when you’ve been through the tough times and you discover they aren’t so tough after all” – Malcom Gladwell (David and Goliath)

Minerals To Metals Symposium 2016

minesearch

Dust Monitoring Equipment – providing equipment, services and training in dust fallout management to the mining industry.

X-ray computed tomography

Using X-ray computed tomography for the 3D textural analysis of drill core in Geometallurgy

Managing ore variability remains an on-going challenge. This study will focus on further developing the method for the quantitative 3D textural analysis of drill core samples scanned by XCT (Jardine, 2016). Here, the robustness of the GLCM will be established in terms of (i) the sensitivity to differently textured ore types displayed by various rock types, as a result of different ore forming processes and (ii) the minimum number of unique 3D pixel-pair relationships that need to be determined to quantify ore texture. Thereafter the focus is on the geometallurgical correlation between quantitative ore texture and comminution and breakage characteristics, by considering (i) which of the textural outputs of the GLCM show the best correlations for ore hardness, comminution product grain and particle size distribution, liberation, and mineral association and, (ii) Are the correlations defined ore specific or can they be generalized for other ores?
The focus of this study will be to use this textural information and correlate it with breakage characteristics, measured from the Short Impact Load Cell (SILC) and JKRBT (Julius Kruttschnitt Rotary Breakage Tester) tests.
Marcelene Voigt
PhD Chemical Engineering
Marcelene juggles between her full-time job as an Economic Geologist at the Council for Geoscience, and her part-time studies. She has mastered the skill of chronic multitasking, and her focus now is to master the skill of perseverance. She hopes to someday transform from a PhD candidate into a PhD survivor.

 

Can minerals industry cluster contribute to sustainable development in South Africa? Case study in Richards Bay
The economic development of Richards Bay has started with a national strategy to develop a deep-water port for exporting coal, the most important natural resource of South Africa in 1970’s. This infrastructure development, together with the overcapacity of coal-fired electricity supply at the time had fostered capital intensive minerals industry to form an industrial cluster around Richards Bay.
However, the recent electricity price surge in the country has raised public outcry over the long-term preferential contract used to attract the investment and there are urgent needs to review the sustainability of the industry, not only its economic sustainability but also social and environmental sustainability.
In this study, as knowledgeable and responsible people are the most important resource for sustainable development, historical contributions of the minerals industry cluster to human and social capital development in the region are examined for future development.
Shuhei Kato
MPhil in Sustainable Mineral Development
“Every man must decide whether he will walk in the light of creative altruism or in the darkness of destructive selfishness.”
-Martin Luther King

Characterisation of Rare Earth Elements in Ion-adsorption clays
With increasing advancements in technology and demand for cleaner alternatives for energy, rare earth elements (REEs) have gained significant prominence as critical elements for future generations. The unique chemical and physical properties of REEs make them challenging to process and beneficiate with much conjecture on the optimal separation of REEs. In-situ leaching of these elements from low grade (0.05 – 0.3 wt. %) clay deposits is a promising alternative due to its low cost and limited infrastructure. The REEs are associated with clay mineral structures, formed from subtropical weathering of rare-earth rich host rocks (granite).
In this study, an ion-adsorption clay sample from Madagascar is characterised using a combination of process mineralogy techniques enabling the characterisation of the REE within complex, inter-layered kaolinite and muscovite. Based on the understanding of the REE deportment to the clay microstructure, suitable processing routes can be designed and optimised to effectively recover the REEs.
Cody Owen Burcher-Jones
MSc Chemical Engineering
“Victoria Concordia Crescit – Victory Through Harmony”
Before we bring peace to the world, we must first find peace within ourselves, and to do that we must find balance and harmony. With that, we can achieve inner happiness, peace between people and harmony with our environment. I strive for this in my work.

Minerals to Metals Symposium 2016

Dust Monitoring Equipment – providing equipment, services and training in dust fallout management to the mining industry.

Integrated geometallurgical modelling framework

Towards developing an integrated geometallurgical modelling framework of the minerals beneficiation chain
Early integration of sustainability decisions into the design of the minerals beneficiation flowsheet offers greater potential for reducing environmental impacts at mining and processing sites. The objective of this study is to demonstrate how integration of sustainability indicators and mineralogical attributes can be achieved in minerals processing flowsheet modelling.
A methodology for achieving this integration is proposed in this study. An existing integrated mineral processing unit model that incorporates parameters that capture the effect of variation in process feed stream mineralogical attributes on model outputs, is developed to output sustainability indicators. The effect of ore variability on overall process performance indicators is determined and a set of potential environmental outputs is identified. A set of sustainability indicators that vary with changes in feed ore mineralogy is defined and rated, based on the model outputs.
Edson Charikiya
Postdoctoral Fellow
Dr Edson Charikinya completed his PhD degree from Stellenbosch University in 2015. He is currently a Post-Doctoral Research Fellow at the University of Cape Town, Chemical Engineering Department under Minerals to Metals beneficiation signature theme. His current and future research interests are focused around the area of sustainable mining practices.

 

An Integrated Modelling Framework
As the mining industry is shifting to more complex operation conditions to accommodate the growing demand for their product and increasing pressure from the more environmentally aware public, new ways of solving these issues will arise from a different angle. A common way to view the mining industry is as an extractive process for a defined timespan. But new technology and modern views on economy introduces us to concepts like circular economy. Here the Mining industry plays a role as a key stakeholder. And new opportunities for mining is on the rise, such as urban mining. Where the mining is a more integrated part of society and have to exist in a more continuous fashion.
The work aims to provide insight in the beneficiation process of a specific plant, to do this a model of the comminution circuit is constructed which contains mineral data such as particle size distribution(PSD) and grindability of the feed, this will run through the model and later be incorporated into the flotation circuits. Where more parameters can be applied and incorporated. This will provide expandability and flexibility where more parts of the beneficiation process is accounted for. This computer model of the beneficiation chain shows the results from a helicopter perspective and can be used for broader understanding and as a wider base for decision making.
Fredrik Axelsson
Visiting Student
I am born and raised in Sweden. Ever since I started my studies in Luleå I wanted to do part of it abroad to get the opportunities to meet and share with people from different countries and cultures. To my great surprise I landed in South Africa.

 

Towards the development of an integrated modelling framework using mineralogy
The minerals industry is currently facing numerous multifaceted challenges spanning the techno-economic, environmental and social spheres. The adoption of sustainability thinking is a holistic approach to addressing these challenges and their relative interactions, rather than just focusing on individual issues. The ability to do so requires an integrated modelling framework that incorporates mineralogy, so that the effect of ore complexity and variability on one or more of these factors can be simultaneously evaluated and optimised.
The objective of this study is to demonstrate how an integrated modelling framework can contribute in achieving some of the sustainability principles. A case study of a poly-metallic sulfide ore is presented in terms of predicting both metallurgical performance (flotation grade and recovery) and selected environmental indicators (acid rock drainage potential). The framework uses a combination of simple flotation models, theoretical mineralogical predictions, and the element to mineral conversion (EMC) methodology. The framework provides a conceptual starting point for a new approach to traditional process mineralogy studies.
Sithembiso Ntlhabane
MSc Chemical Engineering
“It is not the critic who counts; not the man who points out how the strong man stumbles, credit belongs to the man who is actually in the arena, who actually strive to do the deeds, who comes short again and again, because there is no effort without shortcoming.”- Theodore Roosevelt

Minerals to Metals Symposium 2016

Falout Dust 160

Dust Monitoring Equipment – providing equipment, services and training in dust fallout management to the mining industry.