Ann: Commencement of Bulk Sampling at Equador Niobium Project, page-45

They have been separating Niobium from Tantalum for Decades.
Their are pages and pages of ways to do it.

You can buy Plants to do so off the shelf.

They have been doing it for a long time in Brazil,
using various methods to do so such as spiral separation, shaker tables etc.

Tantalum weighs 16 650 a cubic metre
Niobium weighs 8570

With such a difference in weight gravity separation is often used:
"Greenbush Mine has achieved good results by using a peripheral discharge rod mill and a vibrating screen closed circuit"

Then there's other methods previously mentioned in another thread about it such as:

Separation and isolation of tantalum and niobium from tantalite using solvent extraction and ion exchange:

Highlights

• •
  Tantalum and niobium were successfully separated from each other in tantalite.
• •
  Solvent extraction succeeded in removing tantalum from the tantalite matrix.
• •
  Ion exchange separated niobium from the rest of the metal impurities.
• •
  Quantitative recoveries were obtained for both tantalum and niobium.

https://www.sciencedirect.com/scien...ere successfully,rest of the metal impurities.

So it's all been done before,
There are plenty of ways to do it,
It's no big deal,
And easy enough to do....