Combined front end DEM analysis and empirical design process to minimise transfer chute blockages
BMT WBM conducted comprehensive design parameteric studies by DEM analysis in conjunction with the conventional chute design review process. It was proved that the selective DEM analysis enables designers to quantify the effect of design parameters. It also provided the critical operational envelop of the transfer chute if the bulk material handling properties and contact surface characteristics vary significantly.
Within the mining industry transfer chute blockages account for hundreds of millions of dollars in lost review every year. Such problems are often a consequence of poor and/or inadequate chute designs and significant variation of the raw material properties.
In the past the design and operation of transfer chutes for bulk solids has been treated very empirically. In recent years significant advances have been made in the development of numerical programs, such as the Discrete Element Modelling (DEM) for granular particle flows and Computational Fluid Dynamics (CFD) for continuum flows, which handle bulk solid flows accurately and representatively.
By utilizing methodologies which combine skilled advanced analysis technology such as DEM, with practical empirical design rules and on site operational experience, BMT WBM engineers support design engineers and provide an additional level of scientific expertise to increase efficiency and optimize the performance of their transfer chutes design.
BMT WBM had been commissioned by FL Smidth to provide the third part design review on the transfer chute in the stacker and provide recommendations to improve the design. This new stacker was designed for Worsley Alumina for the Calibre project. The proposed stacker is intended to handle cohesive bauxite at high flow rates. As the performance of the transfer chute is critical to the productivity of the stacker, FL Smidth would like to validate the stacker chute design to investigate potential material flow problems and incorporate the necessary design changes if any problems identified.
DEM modelling parameters are correlated to the flow properties test results provide by FL Smidth. DEM analysis has been used aiming to achieve two objectives. The first objective of DEM modelling was to predict and visualize the unfavourable flow characteristics such as blockage, potential spill, build up on the boot chute and spread out of material stream for the worst operational condition. The second objective of DEM modelling was to provide quantitative and comparative information to the designers when they are considering a number of design parameters as well as variations of material properties.
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