UBC Theses and Dissertations

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UBC Theses and Dissertations

A power based approach for the selection and comparison of ball mill liners Mejia Alarcon, Olav


Current technology and simulation software used in the mining industry fail to factor in the effect of liner type and wear on ball mill grinding efficiency and throughput. This thesis provides a comprehensive analysis of key mill operating parameters and addresses the following key research question: how does liner type, lifter face angle, and liner wear affect mill grinding efficiency? The hypothesis is a lifter’s face angle drive a ball mill’s grinding efficiency and throughput independently of the type of liner used. To test this hypothesis, plant data and the profile and lifter face angle of the three most widely used liners are analyzed in terms of mill power draw using Morrell’s model C and MillTraj®. Results show the mill ball charge shoulder angle is strongly affected by the liner lifter’s face angle and that Morrell’s Model C could be improved by including a correction parameter that reflects the power draw of a mill along the service life of its liner. The correction parameter is to reflect the effect of wear on the shoulder angle. Results show that mill grinding efficiency decreases as the liner wears but that efficiency can still be maintained by adjusting the mill speed. The operating work index was found to be an effective tool for identifying increased grinding inefficiency along the liner’s service life. Further research is required to include a wear parameter that indicates the liner profile in Morell’s Model C power equations. It is also necessary to carry out additional research on variable speed drivers (VSD) for mill motors, which could potentially pay back the cost of adding a VSD on ball mills due to the increased grinding efficiency.

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Attribution-NonCommercial-NoDerivatives 4.0 International