The results of two research projects into nano diesel particulate matter (nDPM) were revealed at a forum hosted by the Western Australian Department of Mines, Industry Regulation and Safety (DMIRS) on Monday.

In 2016, the Mining Industry Advisory Committee (MIAC) commissioned the research projects into the physical-chemical properties of nDPM in an underground mine and the potential health effects on workers from exposure.

DMIRS Director of Mines Safety, Andrew Chaplyn, who is chair of MIAC, detailed that diesel engine exhaust (DEE) is a known hazard for mining operations, especially in underground mines where widespread use of diesel vehicles and equipment means control at source, and providing appropriate ventilation is critical to ensuring worker health and safety.

“Now that the research has been finalised, MIAC will consider the findings and make recommendations to the Minister for Mines and Petroleum Bill Johnston,” he stated.

The DMIRS and the Mineral Research Institute of Western Australia (MRIWA) co-funded the first research project which focused on evaluating the physical-chemical aspects of DEE.

In this study tracer gas technology was applied successfully at an underground gold mine to better understand: sulfur hexafluoride (an odourless, extremely potent greenhouse gas) flow behaviour as a surrogate for diesel exhaust, the dispersal of gaseous and ultrafine particulate emissions from diesel exhaust, the impact of ventilation practises on the exposure levels and the potential impact of nDPM on air quality.

The key findings from this study were:

• The tracer gas study of a number of underground mining activities – such as charging, bogging, hydro-scaling, shotcreting and truck driving – demonstrated that during those activities there were relatively higher sulfur hexafluoride concentrations measured during the hydro-scaling and shotcreting activities.
• During shotcreting, the Agi truck operator experienced approximately the same exposure of sulfur hexafluoride from the Agi truck and spraymec exhaust. In contrast, the spraymec operator received almost twice the exposure from the spraymec exhaust than from the Agi truck exhaust. The Agi operator in this instance was at greater risk.
• During a short duration activity in a development heading, an unventilated cuddy (as represented by the stockpile in this study) could be a natural ‘place of safety’ or shelter area for personnel that are in the general area but not involved with the actual activity at a development heading.

 

The DMIRS also funded a second project, which evaluated the possible health impacts of DEE exposures.

20 above-ground and 80 underground miners underwent a series of health screening tests and were fitted with personal exposure monitoring equipment to investigate whether their work exposures had an effect on their health status.

The findings from this research is undergoing peer review prior to publication in academic journals.

Curtin University, the ChemCentre and the University of Western Australia conducted the research in collaboration with the DMIRS and MRIWA.

“The research reinforces DMIRS guidelines on DEE, which highlight the importance of monitoring diesel emissions and implementing control measures to make the environment suitable for workers,” Mr Chaplyn explained.

“This includes focusing on the fuel and combustion efficiency of on-site diesel engines, implementation and maintenance of effective engine filtration systems, adopting good ventilation design standards and regular employee training to promote the importance of minimising emissions and controlling worker exposures.”

The DMIRS recommends mining operators consider technological advancements in monitoring nanoparticles and emerging epidemiological studies when developing their long-term management strategies.

The principles contained in the MIAC-endorsed guideline on Management of diesel emissions in Western Australian mining operations is another tool which could assist mining operators to act proactively and promote a safe and healthy work environment.

The DMIRS Mines Inspectors will continue to conduct research aimed at evaluating underground working environments in order to minimise worker exposures to a range of potentially harmful agents, including DEE.

Mr Chaplyn said previously the Inspectorate focused on evaluating DEE concentrations in underground mines in the Goldfields, and in 2018 a similar campaign kicked off – specifically targeting nanoparticles in underground mines in the Murchison district.

“The diesel particulate research reinforces the importance of managing DEE, and will assist mining operators to develop emission exposure controls and long-term health management strategies,” he concluded.

A copy of the consolidated report on the physical-chemical aspects of DEE is available here.