I think you are spot on, the plant size seems to be the critical...

I think you are spot on, the plant size seems to be the critical decision for NST given the upside of the area and the existing surrounding resources, to me the problem for plant expansion is the cost would fall disproportionately on NST as TAM have a free carried to start of production.

IMO the reason for the delay is they are attempting come to a deal where TAM would contribute part of the cost (or dilutes its holding) for additional mill capacity. This is probably the area for the 'discussions' announced back in February, as normally you would expect NST to proceed without any need for discussion with a junior partner.