Bristow said that governments were, at the same time, demanding more.
The only people who would score in such scenarios were early-stage investors who would take their money and run before commissioning, Bristow said.
Randgold Resources was going ahead with its third mine in Africa and considering its fourth. It was Mali's largest single taxpayer and had provided career paths for more than 3 000 indigenous Africans.
He called on the mining industry to engage in sustainable development in Africa and for governments to forge real partnerships that benefited all mining stakeholders.
Companies content merely to be actors in a passing show would find that the metals boom would go the way of the dotcom bubble, which left behind a few rich people and many regrets.
It took five years to build a gold mine and longer for base metals.
The current boom was already seven years old and such booms did not last for ever.
Africa needed to use the mining industry to building the continent's economy. To succeed leaders would have to demonstrated the courage of true pioneers.
"When we operate in Africa we have an obligation greater than to enrich the gold stock punters. Among other things we must plan for the long run instead of creating exaggerated expectations around projects that are marginal at best," he said.