In Arizona alone, the Department of Environmental Quality estimates that between 40,000 and 100,000 abandoned mines could be scarring the landscape, although a full inventory has never been completed.

Visitors at Saguaro National Park should always watch their step (there are rattlesnakes after all) but now, at least, they won’t have to worry about falling into an old mine. Yes, it’s ...

And if and when these old mines are cleaned up, the cost burden usually falls on the American public. Even more disconcerting is the toxic legacy left on public lands and sacred American Indian sites.