Quarterly predictions, page-117

@miningnut 's miss on concentrate production is an oddity IMO.  so I did some crunching using last 3 years december qrtly data.  of interest:

1. apparent strip rate (total bcm/ore bcm) is getting very ugly -> 2016 :7.81; 2017 : 10.4; 2018 : 14.02.  This is saying that I need to move a lot more material to deliver some qty of ore.

2. Total ore bcm recovered -> 2016 : 1,218,363; 2017 : 1,193,821; 2018 : 1,050,067

3. concentrate production ratio (ore produced (bcm) / concentrate (t) ) all over the shop -> 2016 : 0.51; 2017 : 0.61; 2018 : 0.46.  I think this is saying that the quality of ore is maybe getting better (or that GRR are getting better recovery rates when processing).

On these numbers alone then I suppose you could conclude that by digging deeper, a higher quality ore is being recovered only just not as much of it .  The persistent high C1 costs suggests that it's more likely quality of ore rather than process efficiency ... I think.  

And so the logic and motivation to underground access to the North pit ...  going underground will not be inexpensive and so I expect cash on hand will be fiercely  guarded (... read,  limited dividends...) until the scale of that investment is quantified.

'Twill be interesting ahead.