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Exposure limits for dust

From 1 November 2018, the occupational exposure limit (OEL) for respirable dust at coal mines is 2.5mg/m3. Find out more about the exposure level review.

Queensland mining legislation states that exposure to dust particles must not exceed exposure limits. Workplace exposure limits or standards are airborne concentrations of a particular chemical or substance in the workers' breathing zone that should not cause adverse health effects or cause undue discomfort to nearly all workers.

Exposure limits do not identify a dividing line between a healthy or unhealthy working environment. Natural biological variation and the range of individual susceptibilities mean some people might experience adverse health effects below the exposure standard. Therefore, exposure limits establish a legal or advisory maximum upper limit.

Where exposure cannot be eliminated, all reasonable steps should be taken to minimise exposure to a level well below the exposure limit.

Exposure limits for dust in coal mines, metalliferous mines and quarries are provided below. Additional advice on interpretation of the standards is available in the Guidance on the interpretation of workplace exposure standards for airborne contaminants.

Exposure limits for dust in coal mines

Hazardous substance TWA
Coal dust (containing < 5% quartz) (respirable dust) 2.5
Crystalline silica (including quartz, cristobalite, tridymite) (respirable dust) 0.1
Other airborne dusts as recommended by Safe Work Australia various

Exposure limits for dust in metalliferous mines and quarries

Dust type TWA
Crystalline silica (including quartz, cristobalite, tridymite) (respirable dust) 0.1
Inhalable/inspirable dust 10.0
Respirable dust 5.0
Other airborne dusts as recommended by Safe Work Australia various

Adjusting for longer work shifts

Exposure standards (8-hour time weighted average) may require adjustment when work shifts exceed 8 hours or the working week exceeds 5 days. This adjustment compensates for the greater exposure that occurs during the longer work shift as well as the decreased recovery time between shifts.

An appropriately qualified person, such as an occupational hygienist who has a sound understanding of the toxicology and pharmacokinetics of the substance, should determine whether an exposure standard should be adjusted, and if so how. For more information on adjustment of exposure limits, read: