IMO, I can't see how anyone would say this is not a PBFS.

You have only quoted part of the definition. It goes on through (a) and (b). It all forms part of the definition. First it is positive, then it is bankable.

How do you account for the following sentence then?

"If the report is positive under 5.5(b)(ii) but not under 5.5(b)(i), Teck Cominco may nevertheless elect, in its sole discretion, to deem the report to be a Positive Bankable Feasibility Study."