bdo valuations, page-21

From the Ravensgate report.

In the case of Pre-development, Development and Mining Projects, where Measured and Indicated Mineral Resources have been estimated and mining and processing considerations are known or can be reasonably determined, valuations can be derived with a reasonable degree of
confidence by compiling a discounted cash flow (DCF) and determining the net present value (NPV).

I suppose / guess the Irvine project is not in the above category until a DFS is approved for go .... but analysts do not have that legal limitation and can use NPV.