I recently had the opportunity to spend a day exploring around Butte, Montana and was amazed by the amount of mining that has taken place there. The old-timers called Butte “the richest hill on earth” and had pretty good reasons for doing so.

This mine was a real wonder of engineering, and the water supply and drifts had to be carefully managed to keep it in operation. In fact, it didn’t close due to lack of gold, but instead closed with the fall of the Roman Empire.