Tangs I don't disagree that Oposura is sensitive to the price of...

Tangs I don't disagree that Oposura is sensitive to the price of zinc, lead and silver, but this is true of all mining projects. If prices fall, many mines close, only to open again when prices rise. This is a normal part of the industry.
Raising possibly less than $50M for development is quite feasible for AZS, whereas for a larger project requiring $300M it is quite different. $50M can be raised through debt financing, forward selling or other means and can be achieved reasonably easily. This is where Oposura has advantages. The shallow, near surface and easy to mine ore can be produced, and concentrated then trucked to a mill for refining.
The odds are in AZS's favour.