A question that's been on my mind since I first saw northern...

A question that's been on my mind since I first saw northern cobalt is why were there all the historical drills yet no mine? Why did the previous people leave? Was it decided it was uneconomical, or was it for other company reasons (e.g. Switch to focus on other minerals)?
I'm curious why the N27 decided it was worth pursuing?
Not downramping as I hold shares, but just generally curious and a good answer to this may alleviate concerns from others if they have the same question.
In my mind a huge resource is not important as demand might only be there for 10 years till battery technology changes. Small resource at high grade and shallow depth sounds better to me