As far as I can tell, and please do correct me anyone, if I am...

As far as I can tell, and please do correct me anyone, if I am wrong, the expenditure you are referring to is: 1.paste plant and associated system, and 2. electrification of the vehicles.

I assume the paste plant is going ahead because:

a. long term they would have to buy in rock, or such like, to continue with cemented rock fill because a deficit arises if they want to rely on mine waste for the CRF.

b. with the paste plant they can use and send back underground a lot more of the tailings and hence avoid having to permit and build a second tailings dam needed after accounting for the planned raising of the existing tailings dam. Permitting a new tailings dam would not be easy with the strident anti-mine brigade in Tasmania.

c. I think paste fill has got a better structural performance than CRF and that may come in to it.

As for electrification of the vehicles. I said "my guess is that electrification will add costs, but I could be wrong". I have not researched this but with the high costs of diesel together with John Lamb's comment that the mine's relatively short haulage distances making it particularly well suited, I could well be wrong. Or, there may not be a lot in it and the perceived benefits of a diesel-exhaust free mine may be a clincher.

So, yes I think they may well spend what you call "substantial" sums of money to improve green credentials and I imagine as the obviously good mine managers they are, they will have calculated the likely impact on the bottom line, which could be positive from a mine cost point of view, but for the reasons I have provided, not from increased revenue from Hartree.

Don't get me wrong, my interpretation of how the offtake agreement works may be incorrect, but from the quotes I've provided it seems correct.