Western Australian underground mines are dependent on diesel equipment for drilling, loading and hauling ore and waste rock and transporting the workforce and supplies. Underground mine atmospheres are controlled by a combination of mechanical ventilation, dust suppression and vehicle exhaust controls to maintain contaminant levels below health-based exposure standards and as low as reasonably practicable (ALARP). Ongoing reliance on diesel powered equipment in Australia presents the potential for increased concentrations of contaminants in the working atmosphere resulting from vehicle emissions. This paper describes the changing technologies used to control underground atmospheres, evolving exposure standards and sampling method developments with particular emphasis on those relating to diesel exhaust emissions and the impact on workforce exposures. Historical and current workforce exposures to diesel engine exhaust emissions (DEEE) focus on personal exposure to respirable, ultrafine diesel particulate matter (DPM). As the majority of these particles have an aerodynamic diameter less than 100 nanometres (nm) they are referred to as nano-diesel particulate matter (nDPM). The paper highlights a number of important issues that need to be considered and understood when assessing worker exposure to DEEE and how to ensure that existing controls are still effective.
Briefly, the issues include: 1.the components of the mixture of DEEE; 2.guidelines for atmospheric contaminants to protect the general public compared with occupational exposure standards to protect workers; 3.existing emission standards in Australia compared with international standards; 4.use of real-time monitoring equipment to assist with determining control effectiveness; 5.use of tailpipe measurements to monitor reduced function of in situ controls; 6.comparison of background levels of DEEE in the central business district (CBD) with exposure trends for mine workers since 2002. CITATION:Oding, J, 2019. Working toward a better understanding of diesel engine exhaust emissions for underground mines in Western Australia, in Proceedings Australian Mine Ventilation Conference 2019, pp 249260 (The Australasian Institute of Mining and Metallurgy: Melbourne).