My take on this 8.3 (c) iii : they have to build unless there is not enough financing to build, and at negative cost to produce Cu that should not be an issue.

What? no. That clause is saying that if Teck wants to put this into production that they have to arrange the financing for Copper Fox and can recover the costs from the profits.

This is a bigger point really than whether or not Teck can make the decision whether to put this into production. The fact that they have to arrange the financing means once their decision is made for the 75% we don't need to put any money into the project.