Actually that link is to Sedar

My understanding is that they must simply expend whichever multiple of incurred cost in mine development in order to earn the specified interest

They need to declare which level of back-in they want within 120 days of BFS delivery, ...a one shot declaration option

Upon delivery of the BFS, Teck must immediately convey their Liard interests in the region

That is a substantial topic that has been kicked around here quite a bit

There is extended discussion of the Liard interests in the cited Salazar agreement