SN- and SO-Series filters contain a nitrogen oxide (NO2) suppressant which allows these specially catalysed filters to be used in coal mines, joining only a handful of such passive technologies listed.

The SN- and SO-Series filters have been tested by an MSHA laboratory testing facility and listed for installation on diesel-powered mining equipment, reducing diesel particulate emissions by 85% and 87% respectively, the company said.

SN-Series filters utilise a cordierite (ceramic) filter monolith to trap diesel particulate emissions, while the SO-Series filters use silicon carbide monoliths for enhanced high-temperature durability. Both series are available in a range of sizes to fit applications from 20hp to over 700hp.

Emissions of diesel particulate matter (DPM) are one of the biggest air quality concerns in underground mining. Diesel particulates, due to their sub-micron particle size, penetrate deep into human lungs contributing to numerous respiratory problems.

Carcinogenic activity has also been attributed to diesel particulates, with several government agencies classifying DPM as either a human carcinogen or probable human carcinogen.

Nett Technologies said under MSHA rules, the use of diesel particulate filters is the only solution open to mine operators to meet the proposed regulations.

The surface of Nett’s particulate filters is coated with a proprietary catalyst, which has the ability to lower the soot combustion temperature. In contact with the catalyst, the collected diesel particulates burn out at temperatures found in the exhaust gases during regular operation of the vehicle. Thus, a self-regeneration of the filter is facilitated.

Nett said its filters work virtually maintenance-free on most heavy-duty diesel engines in underground mine applications.