How one startup is recovering copper from old mines that were left for dead in the 1980s

In central Arizona, about 90 miles east of Phoenix, an old open-pit copper mine sits full of water. The mine closed in the 1980s, left to accumulate rain and groundwater. These “pit lakes,” as they’re called, are monitored so that they don’t contaminate the environment, but otherwise they just sit there, a new part of the landscape. That water, though, is full of critical minerals like copper, and in a looming copper shortage, every bit counts. Now, a startup called SiTratio...