Well, my numbers for the expansion spit out a lower NPV (8% and $1700) than without it, and that includes processing oxides. Wiluna sulphides alone, I believe are sub economic at present. I didn't say anything about the AISC. That can be lower than spot and still be an uneconomic project.
They wouldn't be the first mining company to publish an overtly optimistic feasibility study. I'm surprised that you're so happy to take it on face value. If you want somewhere to start, Wiluna OP with it's historical 82% recovery and 13:1 strip is modeled with the same cut-off as Guyere with 92% and 2.8:1. Creative at best.
