20% interestIt should not be that hard to value 20% of interest owned by the related party.
Total outstanding shares of NDM on fully deluted basis is just short of 60 million shares. So, the other 20% interest should be converted to between 12 -15 million shares of NDM. I would consider 13.5 million share of NDM for the 20% interest as fair deal.
However, since it is owned by a related party, God knows what is going to happen. I would come out to double my position in NDM, if finally deal does not cost more than 15 million shares of NDM.