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| Sampling grid at Stillwater Mine |
Background
Continual expansion of the use of diesel engines in the mining industry and the uncertainty associated with the long- and short-term effects of diesel exhaust emissions on miners’ health have focused attention on the control of emissions from diesel engines. The potential exposure to diesel emissions has raised a host of health concerns and garnered interest from various regulatory agencies throughout the world. In 2001, the Mine Safety and Health Administration (MSHA) promulgated two rules, one (30 CFR 57.5060) limiting exposures of underground metal and nonmetal miners to total and elemental carbon and the other (30 CFR 72.500, 72.501, and 72.502) limiting diesel particulate matter (DPM) emissions from diesel-powered coal mining equipment.
To reduce miners’ exposures to DPM and to abide by the measure of current U.S. regulations, NIOSH has formed partnerships with the U.S. underground mining community to work on identifying controls for the curtailment of DPM and gaseous emissions from both existing and new diesel-powered vehicles. To date, the replacement of older diesel engines with cleaner modern engines, improvements in diesel engine maintenance, and the implementation of various diesel emission control technologies, including diesel particulate filter systems and reformulated fuels, are all viewed as effective methods to reduce DPM concentrations in mine air. To assist mine operators with the potentially complicated process of choosing the proper DPM control strategy, NIOSH will develop guidelines to reduce diesel particulate matter in coal, metal, and nonmetal mines.
Potential Outcome
The long-term impact of these guidelines will be that mine operators will have correct guidance as they work to develop a successful DPM control strategy. These guidelines will lay out a multifaceted approach for DPM control, including the use of newer, cleaner engines; alternative fuels; exhaust after-treatment systems; and proper engine maintenance. NIOSH is currently working on several levels to gain the necessary knowledge to complete these guidelines. In the previous 3 years (2002 to 2004), NIOSH completed four field studies at the Deer Creek coal mine and at the Stillwater Mine to evaluate the effectiveness of various filters and alternative fuels as to their ability to reduce DPM concentrations in mine air.
NIOSH is also testing a continuously regenerating trap at the University of Minnesota. If successful, this system will give the mining industry a diesel particulate filter that can be installed and forgotten, at least for 250 hours, or the period between normal engine maintenance. A DPM tailpipe monitor that monitors in real time is also being developed to assist mine mechanics with proper maintenance of mine vehicles and ensure that control technologies are effective.
A filter selection guide that walks mine operators through each step in choosing a proper filter is being designed; currently NIOSH is working with the Queenstake Mining Co., of Elko, NV, to evaluate the effectiveness of the guide. Once these guidelines are finalized, NIOSH will sponsor a series of workshops to explain the guidelines in detail to operators. In addition, the guidelines will be available to all operators through the NIOSH Internet and in NIOSH publications.