When Does Further Processing at the Mine Site Make Sense?

A century ago, new mines were often accompanied by smelters. In Australia, smelters were built at the Daydream mine near Broken Hill, at Kuridala and Mount Elliott near Mount Isa, Broken Hill, Mount Lyell, Mount Morgan, Mount Isa, and more recently at Tennant Creek, Kalgoorlie and Olympic Dam. Now the big miners eschew site-based processing in favour of shipping concentrate to smelters in Europe and Asia. As Chip Goodyear was in the process of vacating his leadership role at BHP Billiton, he was quoted as saying that BHP should concentrate on mining ore and leave æto others the skill set of processing that materialÆ. Yet there are times when on-site processing clearly makes sense. Few companies ship gold ore or concentrate to China for gold extraction. New smelters are being built in Zambia. Solvent-extraction and electrowinning plants frequently produce copper from oxide ores and concentrates while pressure leaching is increasingly being considered for copper sulfide ores. Some argue that on-site processing is best because the waste products can be returned to the ground from whence they came, avoiding potentially large disposal costs in more-populated areas. Copper treatment and refining charges will not remain at $45 per tonne and 4.5 cents per pound forever. This paper examines when it makes sense to use on-site pyro- or hydrometallurgical processes in todayÆs environment and comments on how current trends might alter the balance in future.