I would assume that the 3 companies all have their own way of doing things. I would also assume that none of them will be willing to give Scott a walk through.
I am also aware of the wikipedia "DD" done here and that almost all metals can be acid leeched from ore and processed but most countries frown on dumping chemicals in rivers. That is why they developed other methods. So the "feasibility" from 60 years ago was in a world without an environmental protection agency in almost every country.
Luckily Scott doesn't have to know how to get the niobium out of the rocks.
Robert Yeates has been on board for quite some time now. I would like to think that he has been addressing this issue and would not expect the information he has come up with to be made public. Just as the other companies are not giving walk throughs as you mentioned.