Ann: Thick Intersections of Lithium Pegmatite at Manindi, page-1263

there's other factors too, don't forget location, MLS are in Australia and Canada so there's considered no great risk on location

countries in south America all trade at a discount and are considered pretty risky rn especially when Mexican government just took over all their lithium mines

but there's many other factors too, if its Li, is it brine, hardrock etc, also there's grades, depth(cost to extract), production process, distance and condition of surrounding infrastructure(roads, bridges, ports), other mineral credits, size of resource (mine-life), just to name a few