Research into the control of diesel particulates (DP) has been. conducted by BHP Coal for more than 7 years. Personal
monitoring of employee exposures (n = 480 full shift samples) conducted at nine underground coal mines has indicated
that the exposure of the workforce ranges from less than 0.1 to 2.2 mg/m3 of DP dependent on job type and mining
operation. Approximately 50% of the mass of DP captured is elemental carbon (EC) which is the species currently being
considered by some international regulatory authorities as the exposure standard. Five technologies for controlling DP
were investigated in a combination of studies conducted in an above ground simulated tunnel, in a special controlled
section of underground mine roadway and validated by application in standard coal mining operations at Tower Colliery.
Tests conducted under controlled conditions indicate that dependent on the type of fuel in use, the introduction of low
sulphur fuels can reduce DP levels in return airways by up to 50% and in actual mining situations a reduction of 20% can
be achieved in exposure of the workforce. In addition, subjective responses from the workforce indicate that exhaust
emissions from low sulphur fuels provide lower irritation and a more pleasant aroma. The use of water filled scrubber
tanks reduces the level of DP emissions by 25%. Chemical decoking of engines resulted in a reduction of 20% in DP in
return airways. A commercially available non-flammable disposable dry exhaust filter constructed from synthetic organic
fibres with an operational lifetime in excess of 20 hours was found to reduce DP exhaust emissions by 80%. Investigations
have indicated that the use of increased ventilation to control DP levels particularly in multiple vehicle situations does not
follow a simple dilution factor and in some instances compliance with current regulatory requirements may not produce
the required reduced exposure levels. The results from single component control strategies provide considerable reduction
in exposure to DP, however the most efficient and cost effective control methodology is the use of a combination of
individual systems modelled to operations conducted at each mine.