An observation from Rick Rule, one of the best mining investors on the planet:

"Two things. Your money can go further in markets where the market capitalizations are miniscule like this. But much more importantly, when the sector returns the favor, not only will the small company be worth more but a discovery will be more valuable."

"So the idea that you would diversify your risk among small companies now and enjoy their return to favor is one that has worked for me in prior cycles."

http://www.mining.com/web/rick-rule-mathematics-of-a-resource-portfolio/