I'd say Pretivm is in a different class at this point still. You can't yet compare them to producers and worry too much about IRR yet. You have to view them as a resource play. In that respect, especially given the management, they are still very undervalued compared to say NovaGold, Seabridge, etc. After this recent runup one may be able to make a better case for Exeter for example, but I haven't finished my DD on them yet.
Also keep in mind the Pretivm's resources will without doubt grow with renewed estimates and drill results due out in the relative short term.
High capex eventually yes, but it is these rare huge projects that the majors go after, eventually. More development is needed, and they are unlocking that value day by day.
I still see a great deal of upside here in the near future.