We know that it costs $150m per quarter for magnetite production...

We know that it costs $150m per quarter for magnetite production or $600m pa (excluding depreciation and amortisation, corporate administration, sale, royalties, ocean freight, interest and financing costs).

Cost per tonne
Corporate admin $1.00
Sales $0.25 - only one buyer
Royalty 5% (@ $AUD130.00/tonne) = $6.50
Shipping $5.20
These other costs, say = $13 per tonne = $104m

Finance on $US1,481,000 at 4% = $US59m pa. An educated guess.
Repayment by 2030 = $US100m pa - assuming KML has paid down part of loan already. (Could be wrong).
AUD = .7337 $US today = $US159 = $AUD216m.

So these costs equal $AUD320 pa on top of $600m disclosed above.

So $AUD920m pa for 8m tonnes pa = $AUD115m plus depreciation and amortisation.

So my guess is $AUD115 per tonne to break even.

But to make 20% margin add $AUD23.00 ($AUD184m pa).

So $AUD138 per tonne, but that would have to be every day for next 10+ years.

Then GBG might revalue it. - But GBG cut 48% of $AUD184m = $AUD 88m on 1.497b shares = about 5.9 cents per share.

But I think I am dreaming. Current price appears to be $AUD109 - but will wait for quarterly report to get actual sale price.

Did you know that 40% of the world's iron production is in magnetite?