3. Electronic Theses and Dissertations (ETDs) - All submissions

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    Respirable quartz in coal mines in the Mpumalanga region of South Africa over the period 2002 to 2006
    (2010-04-16T07:27:37Z) Doyle, Bruce Anthony
    Introduction: By 2030 silicosis should be eliminated in South Africa. This statement was made by the Labour Minister, Mr. Membathisi Mdladlana on 28 June 2004 during the launch of the National Programme for the Elimination of Silicosis in Johannesburg. Following this launch the mining industry set its own milestone, which is to eradicate this disease by 2014. Historically research has generally focused on the health effects associated with exposures to coal dust, whilst limited work has been done on personal exposures to respirable crystalline silica (commonly known as quartz), which is the main cause of silicosis in the mining industry. Given the number of people that are involved in coal mining, together with the seriousness of diseases associated with respirable quartz exposure, such as silicosis and tuberculosis, it is important to quantify these exposures. The aim of this study was to ascertain the magnitude of employee exposures to respirable quartz, in the Mpumalanga region of the South African coal mining industry, over the period 2002 and 2006. Objectives: The objectives of this study are: • To describe respirable quartz concentrations in 41 coal mines in the Mpumalanga region of South Africa over the period 2002 to 2006; • To compare respirable quartz concentrations in nine magisterial districts of the Mpumalanga region of South Africa over the period 2002 to 2006, to the South African Occupational exposure limit of 0.1 mg/m3 and the American Congress of Governmental Industrial Hygienists (ACGIH) Threshold Limit value of 0.025 mg/m3; • To describe twenty four activity areas in 41 coal mines in the Mpumalanga region of South Africa, over the period 2002 to 2006, which exceed 50 % of the South African Occupational exposure limit of 0.1 mg/m3 (generally referred to as the action limit). 3 Methodology: The study setting comprises the workings of coal mines within the Mpumalanga region, where various types of occupations exist. The research conducted consisted of a descriptive study of retrospective respirable Time Weighted Average quartz concentration results obtained from mines that use the company Colliery Environmental Control Services (CECS) as their occupational hygiene service provider. CECS provided the data that was analysed for this research. Sample collection and analysis for respirable quartz was done using widely accepted International methodologies. Results: The overall median respirable quartz concentration for all mines were 0.007 mg/m3, whilst the mean was 0.038 mg/m3. The highest respirable quartz concentration measured was 2.197 mg/m3 and the lowest 0.000 mg/m3. The majority of the mines, i.e. 30, are situated in the Kriel, Secunda and Witbank magisterial districts, these districts account for 78 % of the total number of measurements taken. A total of 191 measurements (8 %) and 674 (29 %) exceeded the South African OEL of 0.1 mg/m3 and ACGIH TLV of 0.025 mg/m3 respectively with the Secunda district having the most measurements that exceeded both sets of limits (58 and 205 respectively). The majority of measurements, i.e. 1784 (76 %), were from six activity areas and four hundred and ninety one (21 %) of the total measurements taken were from the continuous miner activity area. The highest ranked activity area is the longwall mining one, which has a median respirable quartz concentration of 0.044 mg/m3. The highest respirable quartz concentration, 2.197 mg/m3, was measured in the roving plant activity area, which was followed by measurements of 1.706 mg/m3 and 1.528 mg/m3 in the continuous miner and unknown activity areas respectively. The longwall mining activity area recorded the most measurements that exceeded the 50 % action limit and 0.1 mg/m3 OEL, these been 47 and 38 respectively. 4 Discussion and Conclusion: This research report describes similar exposure findings as has been reported internationally. Persons employed in the high risk activity areas on the 41 mines studied over the period 2002 to 2006 in the Mpumalanga region are at risk of developing quartz-associated diseases, such as silicosis. Recommendations: It is recommended that the effectiveness of implemented interventions need to be investigated and appropriate intervention strategies be implemented. Airborne quartz contents from the nine magisterial districts and 24 activity areas should be analysed and individual samples taken from the high risk tasks should be individually analysed for their percentage airborne quartz content.
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    Evaluating respirable coal dust concentrations at the face of South African coal mines
    (2009-09-22T12:08:13Z) Ferreira, Ernest French
    Introduction The Department of Minerals and Energy (DME) in South Africa issued a Directive B7, titled “A Guideline for the Ventilating of Mechanical Miner Sections” to the coal mining industry. The main purpose of this directive was to reduce respirable dust exposures at the coal face with the long term objective of reducing the incidence of Coal Workers Pneumoconiosis (CWP). This study attempts to evaluate the appropriateness of the DME approach by comparing respirable coal dust results from personal samples from occupations at the coal face to the results obtained from engineering samples at the continuous miner. Objectives The objectives of this study are to: • Describe personal respirable coal dust concentrations of the occupations within the continuous miner Homogeneous Exposure Group (HEG) in five underground coal mines in Mpumalanga from January 2005 to December 2006. • Describe environmental engineering respirable coal dust concentrations of the continuous miner operator position in five underground coal mines in Mpumalanga from January 2005 to December 2006. • Compare personal respirable coal dust concentrations to Environmental Engineering Dust (EED) concentrations in five coal mines in Mpumalanga from January 2005 to December 2006. Methodology This study is descriptive in nature and was carried out utilizing historical respirable coal dust data from underground coal bord and pillar production sections. Data was supplied by Collieries Environmental Control Services (CECS) who provided a coal sampling and analysis service to South African collieries. Data provided was from five large underground coal mines in the Mpumalanga coal fields. The study population consisted of occupations within the HEG of workers deployed at the coal face who were linked to Continuous Miner (CM) production activities and results from EED sampling. Results When comparing the personal sampling results to EED sampling results for each individual mine, it is evident that all the mines had lower personal sampling results than EED results, thus establishing a definite trend. When combining all the mines in the two data sets it is also evident that EED sampling results are significantly higher than personal sampling results confirming the trend observed on individual mines. Correlation tests carried out between the two data sets indicated that there is no correlation between the personal and EED sampling results. The poor correlation between the two data sets indicates that the EED sampling position is not ideal and does not take account of the actual contaminant levels leaving the coal-winning heading. Discussion and conclusion The DME directive by way of a simple calculation took the countries personal Occupational Exposure Limit (OEL) of 2 mg/m3 and formulated a limit of 5 mg/m3 for EED sampling results. Simple extrapolation of the EED results indicates that personal exposure is exceeded more than two-fold and thus the limit of 5 mg/m3 as set by Directive B7 cannot be compared to the personal respirable coal dust OEL of 2 mg/m3. The basis of the initial calculation used to derive the 5 mg/m3 limit assumed that the shift lengths were in the region of 8 hours and cutting times around 40% of the shift, while most coal mines now have shift lengths ranging from 9 to 10 hours. In conclusion it is evident that the required limit of 5 mg/m3 as set out by Directive B7 cannot be related to the personal exposures limit of 2 mg/m3. Poor correlation results observed indicate that the EED sampling position does not account for the respirable dust concentrations leaving coal-winning headings and may be affected by the re-circulation of contaminated air over the sampling position. In addition the EED sampling position does not give an indication of the respirable dust capture efficiency of scrubber fans.
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