HELENA, Mont. — Butte’s Berkeley Pit is infamously known for its toxicity, but it’s also the site of vital minerals and rare earth elements.

The area surrounding the Berkeley Pit — a man-made lake of toxic water in Butte that would likely kill a human or animal that drank from it — is teeming with life.

The Berkeley Pit in Butte, Montana, has been a source of environmental concern for decades, as its waters—highly acidic and teeming with toxins—have seeped into the surrounding area. But today ...

The Berkeley Pit, however, has a much richer concentration of rare earths in solution and a higher volume of water and is expected to produce 40 tons a year. Dr. Ziemkiewicz believes this process ...