Hi Ally
In that presentation I linked, they mention decoupling of on-site operations and off-site purification.
Iirc, the aim is to initially produce primary grade carbonate on site at SDV (probably a bit over 99% Li2CO3) but to subsequently construct an off-site purification facility to refine this to battery grade (over 99.5% Li2CO3).
Aiming to first produce and sell primary grade carbonate (to others who will purify it), but then to expand and also include our own purification facility. Sounds like this purification will happen off-site and at lower altitude.
That’s my recollection anyway.
Hope that helps and happy to be corrected.