Investigation of grain size distribution of conveyed copper ore for modelling ore flow through a Bunker

Abstract

Knowledge of the particle size distribution of mined ore enables improvement of the main processes of the whole mining value chain: blasting, ore loading and haulage and ore processing. Photogrammetry with image analysis techniques was proposed for the on-line identification of grain size distribution of conveyed ore. Preliminary laboratory tests were performed on the experimental belt conveyor to evaluate the quality of photographs for various camera settings. Grain size distribution of transported copper ore was determined on the basis of photographs taken over the main haulage conveyor that feeds mined material to the underground ore bin located at skip-filling station of the winding shaft. Size distribution slope was calculated using the Split Desktop 4.0 software package to estimate the degree of rock fragmentation. Fine fractions (<10 mm) accounted for more than 40% of transported bulk material. Such a large portion of fine fraction may be attributed to the lithology of conveyed material. Individual rock lumps 600 mm or larger constituted a minor part of the total amount of mined ore. The actual ore granulation influences ore flow through the bin, which was simulated using a discrete element method model to obtain information about the ore stream leaving the winding shaft.