| Summary: | Background:
Tailings dam workers are exposed to tailings dust that has a potential health risk due to the
element contents in the dust. The extent of exposure of tailings dam workers is unknown.
Consequently, the elements, level of exposure, the potential adverse effects to health,
compliance to legislative requirements and the efficiency of the current control measures were
investigated.
Design and Method:
During the trials, 69 personal dust samples were collected during three full production shifts
from tailings dam workers in three different tailings dam environments. The field filters were
weighed to calculate the total dust concentrations. Bulk samples and field filters were analysed
using the 32-element and particle size distribution scans. The between-dam, between-days and
between-group variances were determined to assess the changes in exposure levels.
Results:
The tailings dam workers were not overexposed to tailings dust. Mean exposures were below
the OEL for PNOC, measuring 0,124 mg/m3 (TD 1) 0,366 mg/m3 (TD 2) and 2,956 mg/m3 (TD
3). Three outliers in the data were present in TD 3 and exceeded the action level for PNOC. A
major part of the particle size distribution consisted of inhalable sizes (>I0 μm). Cyclone
tailings dams have smaller particle sizes than spigot tailings dams, though 85% of the particles
in all tailings dams were larger than 10 μm. Some elements identified in the dust have potential
respiratory health effects. No significant differences existed between the three tailings dams
regarding tailings dust concentrations (p=0,527 on 5% significant level and p=0,292 on 10%
significant level). There was, however, a significant difference on a 5% significant level between
the days (p=0,003 and p=0,006). The workers on the cyclone tailings dams had smaller
exposures than workers on the spigot tailings dams, and the pipeline labourers were more
exposed than the mudguards.
The tailings dams did comply with legislative control measures. However, washing facilities for
the cleaning of overalls due to elements in the dust, such as nickel, chromium and manganese
need to be considered. Workers need to be educated in work practices and procedures,
personal hygiene and symptoms that can be experienced after exposure. Engineering control
measures such as water sprayers covering the entire tailings dam, the use of fixed or temporary
windscreens in the area where work is done and covering of the roads on the tailings dam with
gravel or water spray can be considered as dust suppressant controls.
Conclusion:
The study met the issues set out in chapter 1, hypotheses were rejected and accepted and
future studies were suggested. === Thesis (M.Sc. (Occupational Hygiene))--North-West University, Potchefstroom Campus, 2007.
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