It might 'only' be $2B US but it is still may be $2B US that no one wants to put out regradless of the NPV. We don't know that.
My point was ther are a lot of factors that go into the value one pays for a junior mining company - the state of the market, location, environmental, time delay to get mining,etc etc. Right now no one is willing to pay $2 per share let alone $40. Lots happenning in the background for sure but we are not privy to many of the details so we can't really even guess as to buyout interest or price.