Ann: BHP Announces First Production at South Flank, page-19

I've spent a bit of time modelling the expected dividend yield based on the base output of 57dmpta2, the projected increases to 139 dmpta2, and the effect of the capacity payments > 57dmpta2.
And with ore price and fx rate at various levels.
As I understand it, the capacity payments of $1mill per million tonnes of production greater than the current base of 57dmpta will happen no matter what the ore price is, or the audusd fx rate.
Am I correct in these assumptions?
I find it incongruous that if the ore price reduces to (say) $60, and the fx rate increases to (say) 0.80, then the capacity payments could form 40% of the DRR revenue alone.
So DRR will be earning a stupid amount of money just from BHP digging a hole?
Or have I got this completely wrong??