Ann: Pumped Hydro Energy Storage Conference Presentation, page-14

To stockpile mined ore 18 months ahead ( My observation from the Expert valuation cash flow details) of when it is capable of being processed seems to go against the "just in time" mantra of not spending cash before its necessary

As you mention there may be several factors that make sense of this early spend.

I'm inclined to think that the higher grade ores that are being processed first, which underpin the much stronger 2018 cash flows, are coming from deeper in the pit, and the lower grade ores that are being processed after mining stops, are what is going to the stockpiles.

What on face value looks like a negative cash flow plan could possibly be delivering earlier positive cash flows even though a lot is being spent on building stockpiles which sit in the balance sheet as cap ex..

In comparing the forecast to the valuation:-

I notice that the forecast production 22Kt to 24Kt in 2018 falls short of the expert valuation number of 27.6Kt and contrary to that valuation's assumption that mining would be completed in 2018 they seem to be talking about mining continuing through the first half of 2019.

We know that the hedged copper price of $8896 is much higher than the $8,282 a tonne in 2018 in the valuation. If this can be achieved for the full 27.6 KT in the valuation it would add 3c a share to the 15.5 cent valuation.

From my calculations the C1 cash cost used in the valuation for the rest of the mine life after taking out other G and A , Royalties and precious metal credits is $1.56 compared to the forecast $1.65 to $1.80

Which seems to indicate the forecast is more conservative than the valuation so we might be in for a pleasant surprise.