Ann: Mukabe-Kasari Cobalt-Copper Project Exploration Update III, page-281

Given the repeated failure to pick areas which produce well below hyped average results while prospecting an areas which are reputed to either be geographically similar to other successful lithium brine areas and very close to producing cobalt / copper miners I would have been much better off selling some time ago.

I am perplexed how the surface samples they had last time indicated reasonable grades and now we are at a stage where it isn't viable with the drill results we have had to date.

To answer your question:
If they were just unlucky and there are reasonable cobalt deposits in the area they can mine then I would expect it is worthwhile buying at this time.
However, if they continue their streak of looking in the wrong places for Cobolt, Lithium or other high value minerals, then the answer is now.

Ultimately you will need to make your own call.