I'm thinking out loud here - AEM is in the process of making a decision on reactivating the Goldex Mine - why not see what they will pay for the 5% NSR? See how they value it - a portion of those proceeds COULD (I didn't say mgmt should or must do anything) be used for a share buyback. PRB shares are thin now - this places more shares back under PRBs control.
Alternatively, give a special dividend to shareholders. This would goose interest in PRB, and reward those who have stuck with the company (a novel idea, but one more goldies should consider).
Thoughts?