Ann: Mineral Resource Estimate for US listing, page-8

US resource is for in-pit only.

AU global JORC is for in-pit, and everything else too.

SS2 cut the JORC down to 'in-pit JORC'.


princey37: the big change was the inclusion of Cathedral to in-pit, maybe from gold price and pit slope changes (making the mountain, and the low grade less of an issue). I can't tell if heap leach was a new factor boosting the resource estimate, or if the US resource has a different estimation method (eg. a different estimation company, and different assumptions).

Heap leach may be very applicable to Cathedral ore (if heap leach is cheaper than sorting). From memory for Korbel lately: sort out the highest grade, heap leach the rest (Cathedral may be put in with 'the rest'). Vs in SS2: sort out the medium grade, dump the rest to waste (no place for Cathedral in this scenario, unless you sort it).


"extend the life of mine"
Maybe. It depends on the balance - whether it costs much more to expand mining and heap leach for Cathedral (invest in extra trucks/staff/leach pile size), but don't really have to invest in additional sorters or plant size.

Scenario 1: early years remain unchanged (RPM focus), but the mid-years get accelerated with a larger heap leach and additional trucks to mine Cathedral faster (assumption: they don't want to spend money on more sorters, but want to enlarge the heap leach with Cathedral's bulk ore). (Lower discount from discount rate, due to it being mid-years, not late-years).

Scenario 2: they need to sort Cathedral, but don't want to invest in more sorters, so it just extends the mine life. (Higher discount from discount rate, because it's late-years).

If they can boost mid-years production with low incremental CAPEX, then it should boost NPV more than extending the mine life to >20 years (they may find ore superior to Cathedral by then anyway, then have little need for it in late years).


If agglomeration heap leach comes through, then that should help Cathedral's economics more (a margin of safety). (Assuming this resource is using the old heap leach assumptions, not some generous assumptions about recoveries).