It looks like $587mhowever if we work backwards, 1,261m shares...

 It looks like $587m

however if we work backwards, 1,261m shares + 232m options = 1,493m shares x 40 cents valuation = $597.32m, i would assume NPV is $597m

the $597m question, how we got there
after treatment charges @ 15% zinc, 10% lead
4% royalty of total revenue before costs to Myanmar govt. It's their property
50% of profits after costs to the Myranmar govt. They aren't a charity
49% the remaining 50% profits, or 24.5% of profits after costs for partners in BJV. Friends in high places
MYL receives the remaining 24.5% of profits, so this means if the cost of operations relative to revenue is 33%, then MYL ends up with 12.4% of the total revenue as profit 
If we then apply the discount rate on all the annual income streams, add up the estimated amount of payments .... and wah lah, $597m.

how big is bawdwin? Theoretically it has a total NPV, free of taxes, royalties and fractional ownership of ~$4.2b, assuming they don't expand the complex. If they hit high grade, low strip, easy access ore, watch the NPV expand.... and by high grade, i mean 50%+ eqZn