Deep underground, a giant abandoned mine reveals walls coated in thick layers of soot and signs of long-forgotten activity.

Dozens of people get injured or die in the U.S. every year because they don’t follow this simple advice: Stay out of abandoned and active mines and surrounding lands. Abandoned mines are not history ...

From Europe to North America, an energy revolution is breathing new life into empty, long-forgotten coal mine shafts—by repurposing them into places to store renewable energy. Using “gravity batteries ...