Loan of $3b,
10 years to repay = $300m/yr
10% interest = $300m/yr
Total = $600m/yr
Equiv to 30mt @ $20/t or 15mt @$40/t
20 years to repay = $150m/yr
10% interest = $300m/yr
Total = $450m/yr
Equiv to 30mt @ $15/t or 15mt @$30/t
The figures are great but doable.
A loan of $4b would be tricky.