| Summary: | A study report submitted to the Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, in partial accomplishment of the requirements for the degree of Master of Public Health (Occupational Hygiene). === This study identified the risk to CO exposure from unburnt hydrocarbons and explosives used daily underground at a mechanized platinum mine. Existing CO personal measurements over a six month period were utilised to develop a framework or management tool that will assist mine managers and occupational medical practitioners to evaluate and prioritise occupational risk to CO when reference is made to national and international limits including biological indices.
Methods: This study employed a retrospective record review of secondary data emanating from records of the compulsory wearing of gas detection devices underground. The widely used NIOSH method 66904 was used to assess CO exposure which stipulates that a portable direct gas reading instrument will be used.
Results: Exposure results to carbon monoxide ranged from 0 ppm to 40 ppm and confirmed a non-risk occupational exposure index when compared to the time weighted OEL of 30 ppm (Median for total group 0.05). The overall arithmetic mean of 1.6 ppm was higher than the overall mean personal gas concentration of 0.05 ppm. Although the highest percentage of proportional measurements were in the range of 35 and 50 ppm for the occupation, trackless stoper the median result was still far below the OEL range at 0.19 ppm.
Conclusions: The results have shown that personal exposure levels over an eight hour equivalent shift compared to two generally used OELs were exceeded. These levels of over-exposure were however not as great as was expected and the majority of the results did not exceed all three applicable OELs for CO exposure over an 8-hour equivalent. Measurements exceeding the South African OEL of 30 PPM were 0.03 % in total. Of particular interest is that no measurement exceeded the OHSA (USA) limit of 50 ppm. Additionally from the data contained in this report it is evident that all of the data utilization scenarios (literature research, field observations, interviews and data
information gathering) can be calculated, reported and utilised in a Carbon Monoxide Management System.
|
|---|
