General Discussion, page-1286

It makes sense to do DSO in my opinion. Can also add an ore sorter to upgrade the ore's lithium content by about 100% based on other studies for ore sorting lithium ores. PAM is a recent example of doing a study on this. The possibility of similar results (ore upgrade to 2.5-3% from their 1.2% min resource estimate) have also been suggested by RDT.
ESS could then possibly have sorted ore grading around 2.5-3% as well(grade also 1.2%) after sorting the ore. Ore sorting would likely be part of producing spodumene concentrate in any case and wod not be wasted money.
CXO sold 1.4% DSO at US$951/t. Putting that through a plant to produce 6% SC at about 75% recovery would require about 6/1.4/0.75 = 5.333t. So effectively compared to selling 6% SC they achieved a price equivalent to 5.333t x US$951 = US$5072/t.
that is higher than any listed miner has achieved for selling 6% SC on average in a quarter (individual cargoes have sold for higher prices up to US$8000/t).
It is a pretty good result for CXO.
Sorting to the ore to achieve a higher grade (2.5%-3%) would capture some of the implied gap between DSO equivalent @ US$5072 and spot of US$8000. Perhaps as much as have the gap to give an implied 6%SC sale price of around US$6500/t. Obtaining an ore sorter and starting to dig would get ESS more than 80% of current spot prices withouth having to complete a plant to produce 6% SC. Given these high number it may even not be worthwhile to build the plant to produce spodumene concentrate. Especially if you can start selling a year or 2 earlier than waiting to construct a whole plant to produce SC.
Just dig, sort and ship. Much easier than having to run a plant for concentrate production.
All that said the effectiveness of ore sorting would be dependent on a number of factors and may be more or less effective for ESS than results achieved or suggested by other. I'm sure those in charge of ESS would very well be considering this.