Dust exposure during small-scale mining in Tanzania: a pilot study.
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Date
2003-04-01
Authors
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Journal ISSN
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Publisher
Annals of Occupational Hygiene
Abstract
Small-scale mining in developing countries is generally labour-intensive and carried out with
low levels of mechanization. In the Mererani area in the northern part of Tanzania, there are
about 15 000 underground miners who are constantly subjected to a poor working environ-
ment. Gemstones are found at depths down to 500 m. The objectives of this pilot study were to
monitor the exposure to dust during work processes, which are typical of small-scale mining in
developing countries, and to make a rough estimation of whether there is a risk of chronic
pulmonary diseases for the workers.
Personal sampling of respirable dust (n = 15) and ‘total’ dust (n = 5) was carried out during
three consecutive days in one mine, which had a total of 50 workers in two shifts. Sampling
started immediately before the miners entered the shaft, and lasted until they reappeared at the
mine entrance after 5–8 h. The median crystalline silica content and the combustible content of
the respirable dust samples were 14.2 and 5.5%, respectively. When drilling, blasting and shov-
elling were carried out, the exposure measurements showed high median levels of respirable
dust (15.5 mg/m3), respirable crystalline silica (2.4 mg/m3), respirable combustible dust (1.5
mg/m3) and ‘total’ dust (28.4 mg/m3). When only shovelling and loading of sacks took place, the
median exposures to respirable dust and respirable crystalline silica were 4.3 and 1.1 mg/m3.
This study shows that the exposure to respirable crystalline silica was high during under-
ground small-scale mining. In the absence of personal protective equipment, the miners in the
Mererani area are presumably at a high risk of developing chronic silicosis.
Description
Keywords
Crystalline silica, Quartz, Developing country
Citation
Bråtveit, M., Moen, B.E., Mashalla, Y.J. and Maalim, H., 2003. Dust exposure during small-scale mining in Tanzania: a pilot study. Annals of Occupational Hygiene, 47(3), pp.235-240.