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  'Working together to promote premier, multi-disciplinary research and development in the area of minerals beneficiation'

Mine Dust

The Mine Dust Working Group at the University of Cape Town spans across several academic departments and involves government and industry leaders to tackle this problem. This inter-disciplinary working group will provide the necessary expertise to deal with all aspects of mine dust. The aim is to provide integrated solutions to many of challenges faced by communities, affected environments and the industry. This will include the sources, quantification and emission mechanisms, monitoring and sampling methods, characterisation of the dust, its impacts, associated risks and legislation.

Our focus is on finding solutions to the problem of mine dust in developing countries around the world with specific focus on southern Africa, South America and potentially Asia soon. Working group activities to date have been focused on identifying and drawing in network participants, defining the network structure and functions, as well as identifying research areas. The first workshop was held in 2016 and centred around discussions for the need to establish this focus group. This year has seen the development of the necessary capacity to drive this research theme and the second workshop held in July provided the blue print for future network activities. Research to date has been largely through student projects.

PROJECTS

Student

Project


Caitlin Gruning and Emma Chetty
Honours (Commenced 2018)

Project Title: Dust deposition footprint and impact at Saldanha Bay from a coupled ground-based and remote sensing study
Supervisors: Dr Johanna von Holdt, A/Prof Jennifer Broadhurst, CK Kamanzi, Shireen Govender and A/Prof Megan Becker

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Cassandra da Cruz and Ndivhuwo Magondo
Honours (Commenced 2018)

Project Title: Exposure risk of urban industrial particulate matter: are our monitoring methods effective?
Supervisors: Dr Johanna von Holdt, A/Prof Megan Becker, CK Kamanzi, Shireen Govender and A/Prof Jennifer Broadhurst

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Conchita Kamanzi
Masters (Commenced 2018)

Project Title: The development of a protocol for characterizing particulate emissions from coal mining and processing.
Supervisors: A/Prof Jennifer Broadhurst, A/Prof Megan Becker, Dr Johanna von Holdt

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WORKSHOPS

MINE DUST WORKSHOP SUMMARY July 2018
This is the third mine dust workshop held as part of this initiative. The minutes of the previous meetings held in 2016 are available on the shared folder. This group was started with Jenny’s visit to an AAUN (Australia Africa University Network) meeting held by Helen McDonald on mining and health mostly attended by health anthropologists and occupational hygienists. From this meeting it became clear that mine dust is one of these intractable problems that spans many different disciplines and can only be dealt with by an inter-disciplinary, multi-stakeholder group of people which are two aspects that defines sustainability science. In the last two years...

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MINE DUST WORKSHOP SUMMARY June 2016
The inaugural dust workshop was held at Minerals at Metals on the 10th of June, 2016. The workshop, attended by researchers from various research groupings both within and beyond UCT, was designed to establish a preliminary protocol and a plan of action in order to tackle the role of mine dust- its detection, implications and mitigation. Further, the meeting provided a starting platform upon which trans- disciplinary research in this area can be facilitated.

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Dust deposition footprint and impact at Saldanha Bay from a coupled ground-based and remote sensing study

Student: Caitlin Gruning and Emma Chetty Honours (Commenced 2018)

Supervisors: Dr Johanna von Holdt, A/Prof Jennifer Broadhurst, CK Kamanzi, Shireen Govender and A/Prof Megan Becker

The Saldanha multipurpose terminal has been in operation since September 1976. The towns of Vredenburg, Saldhana, Velddrif and Langebaan are nearby. Red iron ore dust stains almost every surface in Vredenburg and Saldhana and resident complaints have escalated with the expansion of the port’s handling capacity of iron ore, manganese, lead and heavy minerals such as ilmenite, zircon and rutile. Some of these minerals undergo some processing within Saldanha Bay before being shipped to overseas markets, such as the production of titania slag and pig iron from ilmenite (Gous, 2006). Particulate measurements are said to indicate compliance with existing ambient air quality standards at Saldanha and Vredenburg (WSP, 2013) with the controversial conclusion that the dust does not pose significant risks to the environment and people. To determine the footprint of potential dust deposition from these activities this project will sample the soils around the Saldanha Bay and Vredenburg area to determine if and to what extent the ore handling and processing have affected the soils. Soil samples will be taken in the field and analysed for specific elements found within the mineral ores with XRF and QEMSCAN or SEM-EDX. In addition, satellite data from a sensor such as MODIS or Sentinel will be explored to see if it is possible to confirm the dispersion of particulate matter from these activities and whether the ground-based results can be correlated with remote sensing data. This could potentially be used to validate dispersion modeling and determine the area of exposure of other mining activities.
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Exposure risk of urban industrial particulate matter: are our monitoring
methods effective?

Student: Cassandra da Cruz and Ndivhuwo Magondo Honours (Commenced 2018)

Supervisors: Dr Johanna von Holdt, A/Prof Megan Becker, CK Kamanzi, Shireen Govender and A/Prof Jennifer Broadhurst

Particulate matter (PM) has been recognised as a key pollutant that can have significant impacts on ambient air quality, the surrounding environment, and human health. South African legislation identifies several criteria air pollutants that has an impact on air quality and ambient standards for particulate matter for sizes PM10 and PM2.5 are specified (SANS1929:2011). In recognition of the important contribution of dust to the particulate matter category, dustfall is regulated and permissible dustfall rates are listed in the National Dust Control Regulations (May 2018) as measured with ASTM D1739:2010. The dustfall bucket method is known to be inefficient for PM10 particulate matter (less than 10 µm) but is regarded as a proxy for the effective management of dust. It is uncertain how well this method of monitoring dust emission, and the way it is currently implemented, captures the actual exposure of humans and animals to these respirable size fractions of dust. This is particularly problematic in urban settings where industrial areas are located adjacent to residential areas with different limits (1200 mg/m2/day average versus 600 mg/m2/day for latter). This project will assess the difference in the results from the dustfall out bucket method to those taken with an active PM10 sampler to determine the potential implications of these differences in terms of the regulations and health risks at an urban industrial point source situated next to a residential area. The quantity, particle size and composition of the dust will be determined with a particle size analyser and electron microscopy such as SEM-EDX or QEMSCAN.
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The development of a protocol for characterizing particulate emissions from
coal mining and processing.

Student: Conchita Kamanzi Masters (Commenced 2018)

Supervisors: A/Prof Jennifer Broadhurst, A/Prof Megan Becker, Dr Johanna von Holdt

The coal industry in South Africa is well established and has historically been a major generator of power through Eskom (Electricity supply commission) since the early 1920s, as well as the creation of liquid fuel generated by SASOL (South African Synthetic Oil Liquid) in the 1950s. South Africa also holds the title of the sixth largest producer of coal globally. The Waterberg coalfield in Limpopo represents the last remaining volumetric resource of coal in South Africa. Multiple prospects have been opened to mine within the coalfield. Currently there is only one established mine in the coalfield. This mine produces feed stock for two proximal power stations and occupies the largest coal washing plant in the world. The region which this mine is located is plagued by water scarcity and has been recognised by the South African Weather Service as a site for monitoring in terms of potential air pollutants. Along with this there is a historical link to the dust emissions and the resultant lung diseases caused by the extraction, processing and open storage of coal further justifying the monitoring of particulate emissions in the area.

Water as a resource is becoming more precious, with the indisputable effects of climate change currently plaguing the world various regions are experiencing harsher dry seasons and delayed or absent rains form one end of the spectrum. With this in mind the future use of water by major industries such as the mining sector is in a state of reform. Coal processing plants in South Africa employ washing facilities to upgrade the mined low-quality coals to market standards.
There has been a shift to drier processes and the reprocessing of fine material. In terms of the mine processing these are extremely advantageous developments. What needs to be considered is the impact of finer (potentially nano-particles) and drier discards entering tailings dams and being entrained in the ambient air. The only regulations outlined in South African legislation on air quality speaks to the volumetric concentrations of inhalable particles one is exposed to. There is no mention of the constituents of the dust particles or the characteristics that they pose which can influence the toxicity of the dust produced.

Various toxicological studies have identified the characteristic factors of insoluble and “low toxicity” dust, of which coal dust has been grouped as, which inhibit clearance in the lung and promote inflammation. These factors speak to the physical characteristics of the particles themselves and need to be identified prior to exposure in order to understand risk and dose once exposed. This study aimsto develop a method to quantify the characteristics of inhalable particulate matter in terms of their physical, chemical and mineralogical properties.