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Abstract

The use of compressive crushing plant such as gyratory crushers within minerals processing operations can generate large quantities of dust as large volumes of ore are tipped into the crusher feed bins. Methods to reduce these dust emissions include the retrofitting of shrouds, enclosures, local exhaust ventilation (LEV) systems and water suppression systems. The operation of these ancillary systems should be optimised to offer maximum performance. It is desirable that the future planning of such facilities include sufficient dust suppression and/or removal systems to ensure that material delivery rates are maintained and the welfare of the workforce is protected. This paper presents the results of an investigation of the tipping process through the application of computational fluid dynamic (CFD) methods and validation using data obtained from scale experiment. A 3-D computational model has been constructed using the Fluent™ <www. fluent. co. uk> modelling software to represent the ventilation regimen within an underground crushing installation. The falling ore has been represented as a granular fluid continuum falling under gravity from the bed of the dump truck. Transient streamlines are used to represent the dispersion of dust due to the updraft airflow generated by the tipping process. A parametric analysis has been performed on a model of the tipping process to investigate the influence on dust dispersion of; the orientation of the dump truck, the surrounding ventilation characteristics and the material tipping rate and volume. The CFD models predict a strong shear-induced flow in the region of the crusher during tipping and a high sensitivity to the surrounding ventilation regimen. These results indicate the need for further experimental studies to characterise the entrainment and transport of dust-laden air into the induced shear flow. An experimental rig has been designed and evaluated for the purposes of conducting validation studies and gaining further insight into this phenomenon. Results of these investigations are presented.

Keywords

VENTILATION UNDERGROUND CRUSHING PLANT COMPUTATIONAL FLUID DYNAMIC METHOD

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The ventilation of an underground crushing plant

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