I have not seen a payment of this nature in any other deals. It would be best for a junior explorer to pay cash/shares for a project, explore the project and then either pay royalties if they reach production, or sell the project to a larger company. It would make sense to only have one initial project acquisition payment and have no further obligations in the future. That component is clearly in the vendor's favour so why would TRH want this deal? It really boils down to negotiation skills and the vendor's and buyer's knowledge of the potential project. As a TRH shareholder, I would like this deal to be huge because of that condition.
That is my opinion and I have no experience in the negotiation and analysis of project acquisitions.
Companies would pay more than $0.1 tonne for Proven Reserves in the current market. It is the highest level in the JORC.