Ann: Shares coming out of escrow, page-34

Tantalum is worth $478 kg
And Niobium is worth $120 kg

The fact SUM has both,
Means 1% of both Niobium and Tantalum,
Is worth 5 Times the Price of Niobium alone.

So a lesser grade is worth just as much,
For example 0.2% of each would still have the value of 1% Niobium Grades.

Though it seems SUM will have much higher grades than that:

"Borborema Pegmatitic Province (BPP), Paraiba State. The province is one of the world’s most important sources of tantalum, rare earth elements (REEs), and beryllium."

"The tantalum grades in Brazil vary according to the region and their occurrences. Paraíba and Rio Grande do Norte have higher grades, ranging from 20 to 45% Ta2O5,"