The Performance of Dispersion Models in Predicting Maximum 24-Hour PM10 Concentrations From Open Cut Mines
Predicted maximum 24-hour PM10 concentrations arising from proposed mining operations are used to identify the land affected by the project and to determine whether residential areas are impacted or not. This paper uses monitoring data from a number of open cut coal mines in the Hunter Valley to assess the performance of the two most widely used models in Australia (ISCST3 and AUSPLUME) to assess dust dispersion. The assessment indicates that the ISCST3 model tends to overestimate the maximum 24-hour concentrations and underestimate the lower concentrations. The possible reasons for this are examined and the paper argues that an important mechanism leading to the tendency for ISCST3 to overestimate short-term concentrations is the way in which the plume-spreading parameters are estimated in the ISCST3 model. Adopting the recommendations of the American Meteorological Society (Hanna et al., 1977) as is done in the AUSPLUME model is shown to improve the ISCST3 model performance.
Keywords: PM10, Modelling, 24-hour over estimation of PM10, ISCST3