Respirable coal dust and silica exposure standards in coal mining: science or black magic?

ABSTRACT: The re-identification of mine dust lung diseases in coal mine workers has prompted much work to be done to improve exposure monitoring and health surveillance in Australia. It is now recognised to be inadequate to talk about respirable dust in general terms, because size, shape and chemical content can affect the adverse consequences of excessive exposure. The Minerals Industry Safety and Health Centre within the Sustainable Minerals Institute undertook a gap analysis to identify needs for further research into respirable dust exposure monitoring and control. One such project is characterising the dust present in different mining atmospheres to understand the contribution of the chemical components, particle sizes and shape to the incidence of mine dust lung diseases in Australian mine workers. Exposure standards were first set in British Coal and have subsequently been adopted by the US and Australia. This paper starts with a discussion of the British Pneumoconiosis Field Research data collection methodology and assumptions on which those initial standards were based. From there the discussion moves into the application of these standards to the US and Australia, the history of revisions to the exposure standard and limitations in sampling equipment and radiological diagnosis of disease.