The Importance of Primary Crushing in Mill Feed Size Optimisation

SAG 2001


As part of its investigation into run-of-mine ore fragmentation, Highland Valley Copper discovered the role of primary crushing in the optimisation of mill feed size. Image analysis methods were used to quality the effect of feed size on mill throughput and showed the in-pit crushers to be an integral step in the preparation of feed for the AG/SAG mills.

In the case of Highland Valley, optimal feed size for mill throughout requires a balance between blasting and run-of-mine crushing. While blasting produces the ultra-fine material beneficial to mill throughput, the crushers are used to control topsize and critical size material generated in the blast. Image analysis-based size measurements will be used to demonstrate the impact of blasting on crusher performance and crushing on mill performance.

An automatic crusher control system incorporating size data was developed to ensure a consistency in product quality not achievable before. Close control of the crusher operation will now allow Highland Valley to further exploit the possibilities of mine-to-mill interaction through “value-added” blasting.