Mine to Mill

One of Dr Kojovic’s most sought after skills has been the implementation of the full Mine to Mill optimization strategy, achieved by examining both the mining and processing operations as a single unit. To this end, Dr Kojovic has worked closely with clients including Rio Tinto Hamersley Iron, BHP Billiton Iron Ore, Highland Valley Copper, Luck Stone Corporation and Teck.

At Teck’s Red Dog operations in Alaska, Dr. Kojovic championed the effort to optimize the grinding circuit and recommend changes to meet their Production Rate Increase target. The changes implemented at the Red Dog operation, resulted in a 20% increase in mill throughput, thereby exceeding the PRI design target. The resulting increase in concentrate production in 1999 was estimated to be worth US$25M. Dr Kojovic also led a mine-mill initiative to address an expected shortfall in 2002 production post the completion of a US$100M VIP project in late November 2001. Dr Kojovic’s recommendations led to significant improvements in ore stockpile planning and construction, superior fragmentation from the introduction of stemming in blasting, better control of the SAG feed size and throughput stability, and improved flotation circuit optimization. The complete Red Dog initiative is estimated to have fast tracked the VIP results by 3 months which, at the low 2003 zinc prices, was worth an estimated US$1.7M.