Yes, it should have read "compounding" since it was not simple addition. Or "combining the effects" would have made sense too. My bad.

Actually the BFS did NOT recommend pursuing expansion opportunities. It was Elmer's news release that recommended it. If anything, the BFS recommended against the expansion because of the logistics of starting such a large mine. An expansion to 180,000 tpd will shorten the mine life to 15 years which risks missing out on a commodity boom cycle. (Yes, additional drilling will expand the mine life but the current data is not adequate to produce a feasibility study.) It's also worth considering that major mining companies are shying away from megaprojects because of cost overruns, so 130,000 tpd will look more appealing than 180,000 tpd in the current environment.

Regarding the economics of 180,000 tpd, it did add 1B to the NPV. However, the capital costs will also increase by roughly 1B so the effect is cancelled out. (KSM's expansion from 120,000 tpd to 180,000 tpd would cost 982M. Ours should be cheaper but I don't know how much cheaper.)

To summarize, it looks like the expansion to 180,000 tpd could help our economics on paper but it may not make sense from a constructability standpoint. It's not a no brainer decision at this point but it is a good option for us to have.