Actually I think it would be easy to value what NOT has, if you are privy to all the information. A major willing to do the 10% buy in would give top dollar for a few reasons.

1. They would own 10% of the company and only need 41% more to control this play. And 90%% for a total take out. If all goes according to plan that further 41% or 90% could cost a lot more in a take over war.

2. They would essentially be funding a junior to do all the leg work in defining the resource for the eventual take over.

3. Regardless of the eventual resource estimate all the risk stays with NOT.

4. When the bids start the major who does the deal will likely get the recommended nod from NOT's management and a close bid would likely go to that major.(of course they will have the best information to feel safe to make the most accurate offer).