The bottom is in, page-8

You'll rarely, if ever see Archaean gold projects reporting Proven Reserves and I'd be willing to bet there would be very few consultants willing to sign off on Proven gold Reserves as part of a DFS either. Reporting Probable Reserves do not prevent a company from advancing a project from DFS to production.

Proven Reserves are more common in bulk commodity operations such as coal or iron ore than may have life spans of several decades.