The site of the proposed Rosemont Mine in the Santa Rita Mountains of southern Arizona. This open-pit mine, a project of the Canadian mining corporation Hudbay Minerals, is nearing final approval after more than a decade of debate. The mine could devastate the landscape, deplete already limited water supplies, and endanger vulnerable local wildlife. Click anywhere on the image to enlarge.

Silver Bell Mine, just northwest of Tucson, Arizona, is shielded from the suburban homes nearby behind rocky hills and barbed wire. Seen from above, it is an upside-down Machu Picchu: vast open pits terraced deep…