Ann: Production Update and FY 2019 Guidance, page-105

I can't help but think oz per vertical metre is a very rough way to compare the economics of different ore bodies, and like you say all these other factors need to be considered. Rules of thumb don't really trump a full feasibility study as I see it.

Having said that, we've seen some pretty poor feasibility studies recently in the junior space so nothing would surprise me.

The actual dilution so far from the first 115 stopes at Mt Morgans has also been in line with the feasibility study so not sure it could be considered 'unrealistic'.