The PEA numbers keep everything static except the variable being...

The PEA numbers keep everything static except the variable being changed. For example, the 20ktpa model, pre tax, equates to NPV 8% $1.777bn less $527m capex = $1.25bn. Now you increase production to 25ktpa the NPV cash flows (excl capex) go up by 1.25x$1.777bn=$2.22bn. Less $527m capex leaves an NPV8% of $1.69bn not $2.033bn. Why? The Worley model keeps the total cost of producing 20ktpa static, it doesn’t increase those with the increase to 25ktpa. If we factor in more capex for increased production this would lower the NPV further.

What pre tax NPV8% will 35ktpa production generate? Surely 1.75x$1.777bn less $527m capex? $2.58bn not $4bn.

I’ve recreated the NPV model from scratch and generated these figures. Would be happy to be proven wrong.