Agree mate, they need to do further testing on mill optimisation...

Agree mate, they need to do further testing on mill optimisation and preferred ore blend ratios The chances remain high that the high pyrite/silica fresh rock will blend fine with Gilbeys porphyry/shale hosted ore. Richard Hay's team managed to successfully blend the shale trapped ore. You'd expect to see further improvements on this as the future process flow plans (grind size, resonance times, blend % etc) are optimised.

I'm more concerned about the stripping costs to re-access the Gilbeys pit.
That nearby waste dump could cause cutback issues.
Doesn't look like there will be any cheap fixes.
Ideally, they find so much ore around Gilbeys pit that they can bulk mine it from underground. Plan B would simply be find extra nearby open pittable ore sources (ARC is one already known OP target).
That would at least allow them to smooth out any large capex spend on a Gilbeys cutback.
Hopefully we'll soon hear more detail around potential base feed options.