In the Southwest, they tend to try to keep them secret.
There’s a mining scar visible near South mountain in NM, part of the Ortiz mountains left from work done in the late 70’s when gold to expensive (for the time). A company went to old mining areas from the 1800’s and because they had more modern equipment, ground up old adobe ruins and reclaimed a fair amount.
The Ortiz ountains have been prospected since the early 1600’s.