That's why you limit the amount of prepaid ore that you commit...

That's why you limit the amount of prepaid ore that you commit to, in the example 40.0mt over three years to raise $2.0b is doable, takes out only 13.0mt from overall ore shipped that you have been paid for and no revenue will be generated.

The balance 147.0mt of ore sold is more than enough to cover other costs, plus your cash reserves in the example gives a good buffer against any further falls in IO or requirement for maintaining assets (capex)

Don't forget by repaying the $1.4b @ 8.00% = $112.0m additional costs savings or $0.70mt, moving them further and further down the cost curve and within striking distance of BHP's costs.

I'm not advocating prepayments of more than say $2.0b.

If the 147.0mt results in realised selling price greater than the all in cost then the cash buffer will increase and not be depleted. The buffer is insurance that may or may not be needed.

The secured and unsecured note holders would be more comfortable in refinancing the balance of the debt and extending repayment dates as $1.4b debt has been repaid and a cash buffer exceeding $2.0b is available.

I bet my b**ls that they are looking at this option as they have done it before on a few occasions.

This is a no brainer in my opinion.