Pollutants from diesel engines in mines could be cut further

NEW ways of reducing the level of pollutants from diesel engines were discussed at a major workshop in the USA on control technologies for diesel equipment in underground coal mines.

Staff Reporter

Speaking on his return from the workshop, Queensland Department of Natural Resources and Mines acting deputy chief inspector of mines (technical), David Mackie, said diesel-powered equipment had assumed an ever-increasing role in the underground mining industry in both North America and Australia, and was now an indispensable part of modern underground mining.

"One of the objectives of the workshop was to review the progress being made in the use of new control technology on diesel equipment to reduce exhaust pollutants from these engines in US and Canadian mines, and elsewhere in the world.

"North America, the most significant user of diesel equipment in the world, is undergoing an exciting technological revolution in diesel engine control systems, driven by the desire to reduce further pollutants from diesel engines," he said.

More than a hundred delegates from major coal mining companies in North America and major diesel equipment manufacturers servicing the American coal mining industry, and overseas participants, attended. Mackie was one four Australian delegates to attend.

At the workshop in Louisville, Kentucky, delegates discussed their experiences in using equipment incorporating new technology to reduce pollutants, and the advantages and limitations of the technology. Methods included sophisticated electronic and computerised control systems matching fuel delivery and engine requirements, the latest developments in catalytic converters, and new generations of exhaust filter systems.

"As well as equipment with new technology, the effects of running equipment on different fuel blends, and the effects of various additives, were explored," Mackie said.

"Results of trials with ultra low sulphur fuel (15 ppm), additives, and mixtures of ethanol-diesel (bio diesel) blends up to 20% were discussed. Results illustrated the complexity of reducing diesel pollutants and the care that needs to be taken to ensure that, in resolving one problem, another is not created," he said.

"Laboratory trials of ultra low sulphur fuels indicated that the production of diesel particulates is reduced when using the fuel, however the mean size of particulates is also significantly reduced. These smaller particles could present a greater risk to health than the larger particles from conventional diesel fuels, and therefore there may be an increase in the overall health risk," Mackie said.

"Field trials using bio diesel indicated a decreased power output from the equipment, but more significantly the flash point of the diesel fuel was reduced. The high flash point of diesel fuel relative to other fuels is one of its safety features," he said.

Mackie added that the issue of diesel particulates is being closely monitored within the Australian mining industry.

"Considerable work has progressed in the development of a new Standard for the use of explosion-protected diesel engines in underground coal mines, and the industry is continuing work in measuring and reducing exposure to particulates in underground mines.

"Additional steps are now in hand to establish an overview committee to implement and monitor other issues associated with the management of diesel particulates in underground mines in Queensland," he said.

The workshop was organised by the United States National Institute for Occupational Safety and Health, and the Centre for Disease Control and Prevention. It was cosponsored by the Mining Safety and Health Administration, the agency that regulates the US mining industry; the United Mine Workers of America; and the Bituminous Coal Operators Association.