Abandoned Mine Shafts Can Use Gravity to Turn Them Into Giant Batteries
21st Century Tech
FEBRUARY 8, 2023
When you read about mines your first thought may be about how energy-intensive extracting minerals from underground can be, and in the case of coal, how polluting. In the United States alone that are more than a half million abandoned mines, most of them from coal. Sand gets stored at the top of the mine shaft. Why the latter?
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