First WITS Mine Health and Safety Research Group Seminar

The first seminar for Mine Health and Safety Research was hosted by the University of the Witwatersrand’s School of Public Health on 22 February 2017. This was a pioneering initiative between the Centre for Sustainability in Mining and Industry (CSMI), the Wits Mining Institute (WMI), and the Wits School of Public Health (WSPH), and proved to be well-received by the approximately 30 attendees.

The morning-long seminar offered a platform for six Wits post-graduate students in the mining and occupational health disciplines, focusing on the causes and effects of health and safety issues facing those involved in the mining industry.  Each researcher presented a paper and delegates had an opportunity to discuss and pose questions on the content of the presentations.

 

Presentations

Dr Declan Vogt (Director: Centre for Mechanised Mining Systems, WMI) opened proceedings with a summary of the purpose and aims of the seminar.  Zodwa Ndlovu commenced the presentations with her PhD research on Autopsy Data for Occupational Disease Surveillance. Zodwa is a lecturer in the Epidemiology and Biostatistics Division at the WSPH. She previously worked at the National Institute for Occupational Health where she managed the Pathology Automation System (PATHAUT) database and developed her interest in occupational lung diseases (OLDs) and surveillance. Autopsy data are the only source of long-term information on OLD in South African miners. The law allows for the examination of the cardio-respiratory organs of deceased miners, with consent from the next of kin, for compensation purposes. Information emanating from these autopsies is stored on the PATHAUT database. Zodwa put forward key findings gathered from analysing the data from 1975 to 2014, showing the usefulness in providing data for the detection and monitoring of OLDs. The findings have led to improved practices, prompting a review of approaches to mesothelioma diagnosis and providing information for the monitoring of initiatives to control silicosis and tuberculosis (TB). Further successes will depend on institutional commitment and the ability to continue analysing the data.

The second presentation was given by Norman Khoza, Occupational Hygiene Specialist at Transnet, and Occupational Health and Safety Specialist at the University of Johannesburg. He is currently a PhD candidate in the occupational hygiene stream d at the WSPH. His research is on ‘Efficient Dust Control Measures for Specific Exposure Scenarios along the Life Cycle of Ballast Rocks.’ Ballast rock is used to support the rail network – it helps to maintain, provide drainage and control vegetation along the tracks. The primary goal of any silica dust management programme arising from the mining and handling of ballast rock is to prevent the development of not only silicosis, but any other disease associated with crystalline silica. Exposure monitoring and dust control technologies have been introduced in the South African mining industries, but these efforts have not yet yielded results that match the investments. Such studies on evaluation and control efforts are lacking in the South African railway industry. In both industries, there is a paucity of studies regarding the full characterisation of health-relevant particle sizes given that the smaller the dust particle, the greater the risk of developing silicosis. In spite of controls such as water sprays in the mining industry, the efficiency of dust capture is limited. Submicron dust particles are difficult to capture due to the diameter of the water droplet versus the diameter of the dust, and high water consumption and cost of maintenance also affect efficiencies. The aim of Norman’s study is to identify and evaluate foam-based dust control technologies for their efficacy, efficiency and feasibility for implementation in the mining and railway industries. There is an urgent need to control and enhance silica dust management.

 Siyanda Mngadi, from the School of Geosciences, is registered for a PhD degree in Geophysics, Seismic Reflection and Mine Seismicity. He presented his research on Integrated Petrographic, Geomechanical and Seismological Studies of Rockmass Behaviour during the Final Phase of Ore Extraction at Cooke 4 Shaft, Westonaria. Seismic events, rockbursts and fault instabilities are prime concerns during the final phase of ore extraction at the deep (>1 km) Cooke 4 shaft. The mine closed in 2001 after 41 years of operation and a shaft pillar was left behind. Mining commenced again in 2010. Siyanda’s research aims to understand the seismic and mechanical behaviour of the rock mass during the shaft pillar extraction operations by studying petrography, geomechanics and stress models, and to establish correlations with monitored microseismicity and underground mapping. Four types of rock were found: quartzite, pebbly quartzite, conglomerate and argillaceous quartzite. Laboratory tests were conducted to measure tensile strength, elasticity, uniaxial compressive strength and triaxial compressive strength. Acoustic emissions were also measured. Rim pillar assessment was conducted to assess if the outer rim of the mined area could be safely mined. Large seismic events often result in infrastructure damage and casualties. In conclusion, it was found that microseismicity is largely influenced by structural discontinuities and ore extraction operations, and by rock composition and geomechanical properties in underground conditions. Understanding weaknesses that could contribute to such events will help to manage safety measures during mining operations.

Nancy Coulson presented ‘In our own voices: The Activities of Workplace, Health and Safety Representatives on South African Mines’. Nancy has a background in public health and social development and works with the CSMI, where she heads the Centre’s mining research programme in social responsibility. Her research examines stakeholder engagement in the mining/industrial sector, with specific focus on the relationship between business and communities and tripartism in health and safety practice. She presented the preliminary findings from case study research into worker-elected health and safety representatives (H&S reps), conducted at four gold, platinum and diamond mines over a period of 16 months. Worker-elected H&S reps are a requirement of the Mine Health and Safety Act of 1996 and every mine with 20 or more employees must have a representative. On large-scale underground mines, an H&S rep is appointed at every designated workplace for every shift. Nancy’s research methods included workplace interviews, followed up by monthly telephone interviews and in-depth semi-structured interviews in English or indigenous languages. It was found that in all areas of responsibility the H&S reps experienced stress, difficulties in trying to do two jobs, and communication problems with language and age barriers. Instead of being supported, the reps felt marginalised. The four areas of activity for a rep are: risk assessment to support safe production; worker education, communication and compliance; supervision of worker health and wellbeing; and administration and reporting.

 The penultimate presentation from Tariq Feroze was delivered via a recorded power-point presentation, as he was unable to attend in person. Tariq is a senior lecturer at the National University of Sciences and Technology in Pakistan and has a PhD in Mechanical and Mechatronics Engineering and Mine Ventilation. He is a member of the Wits Digital Mine Group and is skilled in the use of mechanical designs and Computational Fluid Dynamics (CFD) software. He has developed estimation models to predict ventilation for various mining scenarios. Tariq showed how he used CFD’s advanced numerical code ANSYS Fluent to study the effect of a number of system variables associated with the face ventilation systems used in the blind headings. The blind headings in room and pillar mining are known to be the high-risk areas of the coal mine, since this is where the coal production is actually taking place, and hence where the maximum quantity of methane is found. Ventilation using auxiliary ventilation devices may be planned and be the subject of mine standards, but it is not very well understood, and implementation is usually left to the first level of supervisory staff. The study of face ventilation systems can be carried out experimentally but it is difficult and disturbs the mine production cycles. The South African coal mining industry can benefit from the outcomes of Tariq’s study, especially the mathematical models, in a number of ways. Ventilation engineers can estimate flow rates; the results of the study can be developed into training aids; and it can be used by academia as part of the curriculum to teach future mining engineers as a basis for improving the working environment for underground mineworkers.

The final presentation of the morning, by Amu Modau, focused on the Burden of Air Pollution from Diesel Exhaust Emission in Underground South African Mines. Amu started her mining career at Goldfields East Driefontein in 2007 as a ventilation graduate trainee. She currently works for Modikwe Platinum Mine as a SHEQ Manager and has been exposed to both conventional and board/ pillar mining. Amu has a passion for occupational hygiene, safety and ventilation systems. She is currently a PhD candidate on the occupational hygiene stream  at WSPH. Diesel exhaust (DE) is the major component of particulate matter in the underground environment. During 2012 the International Agency for Research in Cancer classified diesel exhaust as being carcinogenic by inhalation. The small size of the particulate fraction of DE, called DPM, makes it an excellent medium for absorbing organics, and it is highly respirable and able to reach the deepest parts of the lungs. The exposure to DE for underground workers is of great concern because of the confined spaces in which they operate. The first step in reducing worker exposure is to reduce the DPM from the source. However, the monitoring of vehicle emissions remains a challenge in South African mines in the absence of an Occupational Exposure Limit (OEL) for DPM by the Department of Labour, and there is a need to regulate the exposures and to enforce compliance thereof. Ventilation systems are a major dynamic control in underground mines for the dilution of ambient gases and particulate matter. Leading on from Tariq’s studies, Amu’s findings suggest that Computational Fluid Dynamics can be an effective way to simulate the airflow patterns for the entire mine which can be used to implement  a risk-based monitoring system to manage over-exposure.

 

Way Forward

Many useful suggestions were raised from the floor. Agreement was reached that the way forward was for further collaboration on research and ideas instead of working in isolated silos. Fred Cawood, Director of the WMI asked if future seminars should be half- or full-day events, and if a keynote speaker from outside the Faculties should be invited. A further suggestion was for a theme-based seminar, such as mine ventilation, although some felt this could be restrictive. However, an event-based theme, for example, the Lily Mine disaster, could prove to be more inclusive of other disciplines such as medical geology. Dudu Magazi, Associate Lecturer at the Wits School of Mining, asked if future seminars should be open to industry as well as academics, and perhaps a case-study from industry could form part of the presentations.

Dr Vogt proposed that seminars be held twice yearly and that half a day be dedicated to presentations from post-graduates followed by a half day theme-based topic, with industry participation.

In conclusion, the inter-faculty collaboration was a great success.  The event demonstrated how significant capacity can be mobilised when existing Wits resources collectively target a specific theme or industry problem.

The presentations (except Tariq Feroze’s) can be requested from WSP (email dudu.mditshwa@wits.ac.za)

 

Report by: Anne van Vliet

e-mail: anne@communiquepr.co.za

 

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