The application of computational fluid dynamics to the improved prediction of dust emissions from surface quarrying operations

The extraction and processing of minerals from surface quarries can produce significant fugitive emissions as a result of attrition and re-entrainment processes. Dust generation, liberation, re-entrainment and dispersion present serious environmental, health, safety and operational issues. The initial re-entrainment and subsequent dispersion of fugitive dust presents a process complicated by the combination of man-made topography, natural topography and the dynamic nature of emissions unique to these sites. These factors impact upon the accuracy and reliability of established gaussian plume based models where accurate source characterisation is imperative. This paper presents a study on the potential benefits of using CFD as a means by which emissions sources can be more accurately characterised and subsequent localised dispersion modelled with due regard to the localised turbulence and secondary flows typical of these sites. Atmospheric flow field data is provided via CFD simulations performed on a UK case study site. Blasting emissions are modelled through lagrangian particle tracking incorporating a dynamic momentum source representing the initial blast front. Haul truck emissions are characterised through the simulation of a CAT777D dump truck and assessment of the dispersion of re-entrained particulates in the immediate vehicle wake zone. The results are compared to conventional gaussian plume based models and site field study data.