Ann: High-Grade Mineral Sands Discovery, page-28

random reading.

the assemblage means the proportion of rare earths that make up the THM. This has as big effect on value of the deposit as the grade does. Of course higher grade is fantastic, but because you are mining 5 or 6 'products', each of which has significantly varying value, the proportion of higher value products is also very important to the overall value of the deposit.

Im looking at wederburn as an indicator of FALs deposit.

FYI the most valuable products are:
rutile and leucoxene because they have very high concentrations of titanium oxide (pigment)
then zircon (tiles?)
lastly ilmenite which has lesser concentration of titanium oxide (pigment)

the wederburn deposit contains only 33% ilmenite. the lower the better
it contains over 50% of the much more valuable rutile+leucoxene+rutile . higher the better

this is the best overview Ive seen so far

https://*********.com.au/mineral-sands-stocks-asx-ultimate-guide/