Micro Fresh diesel exhaust filters incorporating 3M high performance polymer media have been used effectively and without incident by Australian coal mines for over 15 years and is now helping NSW operators meet legislation recently passed by the Department of Primary Industries that limits underground diesel emissions.
Whereas mines have previously governed their ventilation system on gaseous emissions, an example in the guideline points out that more than 3 times the required ventilation air quantity may be required to disperse particulate emissions (in comparison to gaseous emissions).
Increasing ventilation to these levels is expensive and generally not feasible and as such, operators are increasingly looking to Micro Fresh / 3M for emission control solutions.
3M have had a strong association with Micro Fresh Filters for over 15 years. The innovative abilities of 3M's Australian and US technical development centres have allowed Micro Fresh to develop a product range that exceeds industry expectations.
Their flagship DA100 exhaust filter is becoming an industry standard in Australian coal mines and shows strong export potential also. Mines in the USA, Canada and South Africa have either begun using DA100 filters or indicated intention to do so in the near future.
While diesel particulate has been known to cause headaches, nausea, eye and respiratory complaints for some time, the US EPA and World Health Organisation have also listed it as a known carcinogen.
A desire by BHP Billiton to protect miners from the dangers of DPM was the impetus behind 3M / Micro Fresh developing this technology.
The three parties worked closely for more than 10 years to ensure that the resulting technology produced is the best and continue to liaise on a regular basis to fine tune and develop new technologies as required.
This resulted in BHP Billiton reducing maximum DPM emission levels from 0.6 mg/m^3 in 1993, down to 0.1 mg/m^3 by 2001.
So what is so special about the Micro Fresh DA100 exhaust filter?
The incorporation of 3M high performance polymer media results in the filter having significantly different qualities to all other (known) exhaust filters on the market.
The fact that the media will not burn when subjected to temperatures in excess of 960° Celsius; (Tested to IEC60695-2-1) it will simply melt if subjected to above average operating temperatures.
This is of vital importance in the methane rich environment of an underground coal mine.
There have previously been incidents in America where the more traditional paper exhaust filters have caught fire. This led to the United States coal industry removing disposable exhaust filters from underground vehicles for a period, to the potential detriment of underground miners' health.
Now with flame resistant 3M high performance polymer media, the solution is at hand.
The patented 3M media is an advanced substrate Microfibre filter media that consists of a bunch of nested long strand polymer fibres attached to a supportive backing scrim.
An inherent electrostatic charge combined with the torturous path made by nested fibres results in the media being able to capture a wide range of respirable particles at a higher efficiency and with a much lower pressure drop than traditional paper media.
This is of vital importance in exhaust filtration applications where back-pressure can cause degradation of engine condition and performance.
The media is also more durable than paper and will not support growth of mould, mildew, fungus or bacteria.
Micro Fresh engineers are also successfully using this technology in non-coal mining and general above ground enclosed space applications where diesel particulate poses a health risk.
Examples include forklifts and loaders in warehouses / bulk handling facilities / ships holds / tunnels / subways and marinas.