Summary

• Historically, the mining industry has relied on a standard approach to project development: stress-testing new assets using highly conservative commodity prices.
• The most striking feature of the copper dataset is the magnitude of the discount applied during the commodity supercycle of 2006–12.
• After copper prices peaked and retreated, the relationship between assumptions and spot prices shifted.
• The copper bull market of 2021, when spot jumped to $9,317/mt, triggered a return to conservatism, though more moderate than the 2006–12 episode.

This article is the first in a three-part series examining how base-case commodity price assumptions, used in mining feasibility studies, compare to prevailing market prices at the time of publication. This article uses a dataset of 573