Ah... What? Are you throwing out the Teck Agreement now too? Just because "no one uses 12% NPV" doesn't mean that Teck can't have it written into a clause in a contract signed by both parties. This agreement is only 11 years old.
The 12% is only one level of a test of the economic viability of the project. 8% is another. I understand the Agreement to mean that, if we meet 12% test, then we are away to the races; if we don't but meet 8%, Teck will want to have a closer look for their own protection.
As far as the comment about 'imaginative conjectures', what about all the conjecture about the handshake deal between Teck and CUU to stop drilling and let the 171M tonnes slide? Where is any of that written?