The first requirement is permission from a land owner. This can be tricky and it’s always a bit nerve-racking to approach a stranger cold with such a request.

The father-son duo spent years combing this bit of Pennsylvania wilderness with high-end metal detectors, drills and other tools to prospect for a fabled cache of Civil War gold.

The red dot on the diagram points out where the gravels there were also carrying, but not as much color. The gold was sparse below the point indicated.

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.