Ann: Next drill programme to grow Lithium Resource, page-29

The most basic differentiation between spodumene (hard rock) and brine:

Brine = higher capex (funds to build the project) but lower opex (fund to run the project) and long life (Olaroz life of mine is something like 200 years)
v
Hardrock = lower capex but higher opex and short life. (some of the current batch of hard rock hopefuls have a life of mine as low as 8 years).

This differentiation matters naught with current and expected prices but during the most recent price crash (and the Chinese reneging on contracts) there was carnage amongst the spodumene players but the brine operators could keep plugging along. But lowish prices in the past also explains why Olaroz stage 1, Allkem's flagship project, was the first new brine operation to be built in over 20 years: the lowish prices could not justify the capital expenditure. Now that prices are higher there are a number of companies looking to build new brine operations.

Also historically the brine operators were perceived to be more like chemical manufacturers and the hard rock guys were typically miners. That is also changing as some of the local spodumene miners are looking to go downstream in competition to the Chinese. This tended to mean that the brine guys had better PE ratios than the hard rock "miners" (again, I think that differentiation may be getting smudged).