Add Yahoo as a preferred source to see more of our stories on Google. As the September evening inched along, the line of residents waiting their turn for the microphone held steady. Filing down the ...

Drilling fluid, often called drilling mud, is typically a slurry of fresh water mixed with bentonite clay and small amounts ...

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 ...

Beneath parts of the Appalachian Mountains, thousands of mine shafts still descend deep into the earth. Some of these ...

As the September evening inched along, the line of residents waiting their turn for the microphone held steady. Filing down the auditorium aisles at the Indiana University of Pennsylvania, they were ...