A MELBOURNE-based firm is promising coal miners a cleaner, safer and healthier working environment. The company, Micro Fresh Filters, says its DA100 diesel exhaust filter has already been shown to slash diesel particulate emissions from underground vehicles. Its ingenious filter design, developed over the past five years with input from a local colliery, is already attracting significant interest from around the world.
MFF director Ray de Jersey said diesel emissions continued to be a major issue for underground coal mines. Its filter is now being used by all BHP Coal mines in New South Wales, and also by Powercoal mines in the state’s Newcastle coalfield. “The world market potential for the filter is considerable and we are already quoting for mines in the UK, Canada, Zimbabwe, South Africa and Romania,” de Jersey said. The company is also hopeful of cracking the US market.
The DA100 disposable filter can remove diesel particulate down to 0.3 micron particle size. According to de Jersey, it is 0.3-1 micron particles that can remain in a miner’s respiratory system and cause health problems.
“Until recently mining vehicles relied on catalytic converters and in some cases paper filter elements to reduce diesel particulate,” he said. The former were expensive and relied on high temperatures to operate, which was not acceptable in coal mines. In many cases, they still did not remove sub-micron particles. Paper filters encountered problems with high exhaust temperatures, they could not tolerate water and could not comply with ignition safety standards.
“The DA100 on the other hand is installed after a water scrubber to reduce temperatures, and will not ignite at temperatures up to 960C,” de Jersey said. “The filter material is unaffected by water, it is lightweight, simple to install and remove, and is inexpensive.”
Measuring 260mm in diameter and 496mm in length, the DA100 filter uses an electrete filter media to remove diesel particulate with electrostatic and mechanical capture methods. Removal of 0.3-0.7-micron particulates at 10cm/second face velocity is said to be achieved at a 95% efficiency level. The pleated filter material also will not support the growth of mould, mildew, fungus or bacteria, according to de Jersey, and is bonded to a metal end-cap at both ends using a semi-rigid silicone with an ignition temperature rating of more than 900C.
