Respirable quartz in coal mines in the Mpumalanga region of South Africa over the period 2002 to 2006
Date
2010-04-16T07:27:37Z
Authors
Doyle, Bruce Anthony
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Abstract
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).
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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.
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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.
Description
MPH, Occupational Hygiene, School of Public Health, Faculty of Health Sciences, University of the Witwatersrand, 2009
Keywords
respirable quartz, coal mines, Mpumalanga, South Africa