New Safe Work Australia Workplace exposure limits for airborne contaminants - April 2024.

[Lieb Combrinck]

Have they genuinely lowered DPM (as respirable elemental carbon) to 0.01mg/m3 or is this a typo?

[jkok@mtvent.com.au]

If this is not a typo, there will be a need to seriously revise the DPM management strategies for workplaces. Not just mines, but tunnelling and even open-pit mining. How does one control the airborne contaminant levels in general public areas if weather conditions prevent fumes from clearing? Taking air that is already polluted and then using this for ventilating sub-surface areas, will certainly need additional engineering and/or stronger mitigating controls.
Carbon Monoxide is lowered from 30 ppm to 20 ppm as well.
NO has been lowered from 25 ppm to 2 ppm.

Will need to go through the rest of the contaminants to compare what we are currently working to and what is to go live in 2026.

[craigstewart]

Looking at their website there are a number of historical documents. In 2015, a diesel contaminant paper mentioned the exposure limits were managed by the mining regulators at 100 ug/m3 elemental. Then last May 2023, a proposal of 15 ug/m3 was submitted for public review.

https://www.safeworkaustralia.gov.au/me ... ate-matter

Now it seems 10 ug/m3 has been adopted - not a typo I'm assuming....

[jkok@mtvent.com.au]

Also picked up that the exposure standard for NO has been reduced from 25 ppm to 2 ppm which then also confirms that the reduction of the exposure standard for EC from 0.1 mg/m³ to 0.01 mg/m³ is true. This is a huge step-change in my opinion with not a lot of time to meet this.

There has been a lot of discussions and research done in the past. A lot of development of different ways to monitor DPM, modelling etc really started to show the way into active DPM management. There is still a lot to be done in terms of DPM management through ventilation as well. Challenging the norm may be one of the next steps. This is clearly not going to be a ventilation only solution or replacing diesel equipment with something else. Each mine/workplace will need to fully understand how the changes in equipment and strategies may affect the risk to health and safety in the workplace. Fixing one thing may cause a new problem. Understanding this takes time and focus.

Thoughts?