One would think that the “science” of economics could lend itself to areas of high agreement between professionals, but that has hardly been the case throughout history—and it is not the case today.

• ESA changes for the better

Let’s set up a thought experiment: Suppose you had some material that ran one ounce per ton gold, which is generally considered high grade to fantastic grade depending on the circumstances.

The problem is that extracting gold from hard rock is often a lot more difficult than processing placer gravels. Still, there is some very high-grade ore out there in many old mining areas.