Let's no overstate things.A 1.5mtpa mill isn't worth anywhere...

Let's no overstate things.
A 1.5mtpa mill isn't worth anywhere near 4bn$.

Wodgina alone with 1.15% LiO2 ore reserve, ~70%ish recoveries and 900Ktpa of 5.5% spodumene concentrate production means they munch through roughly 6 mtpa before trains 4, 5 and 6.
That's already 4x the LJ mill throughput, it's brand new and that comes along with one of the largest and best Li deposit in the world at [email protected]% LiO2.

And that was valued 2.3bn$ US through the Albermarle deal so close to 3.5bn$ AU.

There's no denying 15m$ is excellent value though.

In the same vein, at current prices of SC (1000US$/t) and for a 1.5mtpa, 70% recoveries and 1.2%LiO2, Min will get roughly 210ktpa of SC6 for 210m$us or 323m$Au, which will be around 2.4m$au per year in royalties.

Could go higher if MIN decide to expand the mill later if the surrounding deposits allow that investment.