But what's the AISIC?

The problem with SPX's finds is that they are mainly deep, very deep.
Nice to have some high-grade au over reasonable intersections but not so good if you have to dig down multiple hundreds of metres to get it out.
Open cut mining is possible to about 150 metres depending on a range of geological factors. An AISC of around AUD 1100 /oz/au is about average for an open cut gold mine and provides a healthy profitability of another AUD1100 0z/au
That all changes when underground mining is needed. CAPEX skyrockets and the AISC is much higher. Profitability falls dramatically.
Very high grades in a large jorc centralised in a relatively small area are needed to make Penny North viable.
As for the CAPEX of several hundreds millions of dollars. Investors will be saying 'ok this may be profitable now with the high POG but in 5 years? 10 years? Younami itself was closed even though it still had high-grade gold when the POG fell.
The hope for SPX was for more shallow high-grade gold. A model where a mine starts as open-cut and generates cash that is then used to fund underground mining was seen as likely.
RXL have this model in mind over at Younami, high-grade au from just a metre down will generate a strong cash flow and pay for CAPEX.
But the SPX ann yesterday dashed near term hopes for that model. A couple of hundred metres underground is not open cut and the AISC will be very high. Short intersections very deep and even low grades do not help. Why mention 3m at 3.28 g/t at 174 m? Likely that will never be mined. It is mentioned for the uninformed but yesterday showed that investors are much more aware of the challenges SPX faces

My Opinion DYOR