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| Orange cloud produced by blasting at a surface coal mine |
Description of Problem
Over the past 10 years, large surface mines have been plagued by large orange or red product clouds produced by their large-scale blasting operations. The orange or red color of the cloud indicates high concentrations of nitrogen dioxide (NO2), a highly toxic gas. There has been increasing concern over the effect of the NO2 in the blasting product clouds on workers and neighbors.
Research and Development Activities
On May 25, 2000, NIOSH researchers met with members of the Wyoming Mining Association (WMA) Red Smoke Committee to discuss how our research might help them to monitor and minimize the occurrence of blasting product clouds containing excessive concentrations of NO2. The committee asked NIOSH for help in developing a plan to monitor NO2 at its mines. A 3-year research project at the Pittsburgh Research Laboratory (PRL) was initiated to determine the causes for excessive NO2 production in blasting. The research identified key factors that influenced the quantities of toxic fumes produced by various blasting agents.
R&D Outputs and Transfer Activities
PRL explosives researchers explained that they had used a variety of instrumentation to measure NO2: a wet chemistry method, a chemiluminescence analyzer, a fixed electrochemical cell-based system, and portable electrochemical cell-based systems. NIOSH researchers also told WMA personnel that research had shown that excessive NO2 production could be related to poor confinement, poor explosive formulation, and water contamination of the explosive. NIOSH recommended methods and strategies to reduce NO2 production and minimize the potential for miner exposure.
Description of Intermediate Outcome
The gas monitoring protocol recommended by NIOSH researchers was incorporated into Thunder Basin Coal Co.'s action plan submitted to the Wyoming Department of Environmental Quality on April 7, 2000. It was also incorporated into the WMA's Powder River Basin Short-Term Exposure NO2 Study. The mines in the Powder River Basin incorporated NIOSH research results into their blasting plans. These included lining blastholes and shooting with 100% emulsion blasting agent rather than ANFO/emulsion blends.