NOx emissions from blasting operations in open-cut coal mining

The Australian coal mining industry, as with other industries is coming under greater constraints with respect to their environmental impacts. Emissions of acid gases such as NOx and SOx to the atmosphere have been regulated for many years because of their adverse health effects. Although NOx from blasting in open-cut coal mining may represent only a very small proportion of mining operations' total NOx emissions, the rapid release and high concentration associated with such activities may pose a health risk. This paper presents the results of a new approach to measure these gas emissions by scanning the resulting plume from an open-cut mine blast with a miniaturised ultraviolet spectrometer. The work presented here was undertaken in the Hunter Valley, New South Wales, Australia during 2006. Overall this technique was found to be simpler, safer and more successful than other approaches that in the past have proved to be ineffective in monitoring these short lived plumes. The average emission flux of NOx from the blasts studied was about 0.9 kt t−1 of explosive. Numerical modelling indicated that NOx concentrations resulting from the blast would be indistinguishable from background levels at distances greater than about 5 km from the source.