G'day Mack. I've done some calcs in a similar vein and I get...

G'day Mack. I've done some calcs in a similar vein and I get 334,000 metric tonnes of copper. That's using the following:
The full dimensions (1300 x 300 x 24)
Average grade of 1.5%
Factoring in a recovery of 85% (which I think is safe)
Using a density value of 2.8 tonnes / cubic metre

That last number (density) is the biggest difference between our calc assumptions. While chalcocite might have a density in the fives, I don't think the dolomite and other host minerals will be that high. My figure of 2.8 is probably unnecessarily low, but I haven't seen a nominal / typical density value for the storm area yet. So I've used 2.8 which is the density of dolomite, the predominant mineral surrounding the Cu-containing minerals in the area (investor presentation from the announcement dated 21 July 2023). The average will be better - 2.8 is the worst case, IMO. Hope this helps. The current 13c entry price seems cheap to me, for such a potential resource and so many other opportunities waiting in the wings - though of course everyone has different risk appetites. Happily pretty much everyone who attempts to quantify this is getting numbers that are at least order-of-magnitude similar... and what a nice magnitude it is.