The other thing to remember
is the price per ton/barrel/fridge of your resource
Getting oil from the north sea was daft at $15/barrel because you'd never cover the capital costs
At $50 though....
Its the same with all resources, Rio Tinto maybe sitting on a claim of 1 billion tonnes of silver ore, but its going to cost more than the current price of silver to extract any of that silver.
In 25 yrs time, there maybe a technology to cheaply extract the silver, or the price of silver risen to the point where it is economic to extract.
Until then, we'll have to put up with the "experts" running around saying we're running out of pork... silver and whatever else generates a 1/2 decent headline