Ann: Notice of General Meeting - Leo Lithium Demerger, page-44

Quick back of envelope calculation

Current MC FFX $1.14B
LEO MC pre cap raise $732M
So Net FFX Gold MC $408M
But FFX retains 20% of LEO $147M so total FFX = $555M


So if you hold 100,000 FFX you will end up with:
100,000 FFX shares @55.5 cents
74,218 LEO shares @ 70 cents

Plus whatever additional LEO shares you apply for at 70 cents

But of course as they are both undervalued both shares will likely open higher after the demerge.