Open-pit mining at Kennecott Copper Mine, also called Bingham Canyon Mine, in Utah
Witold Skrypczak/Alamy
The leftover ore discarded by US mines is packed with key minerals – enough to provide virtually all of the raw material needed to build clean energy technologies. Recovering just a fraction of these minerals could meet the country’s growing demand for green energy without requiring imports or environmentally-damaging new mines – but getting them is easier said than done.
“We have to get better at using the material that we mine,” says Elizabeth Holley at the Colorado School of Mines.
Currently, most individual mines focus on extracting just a few types of minerals, such as copper or gold. That involves digging up ore, crushing it and then separating out the main product using various metallurgical processes. Everything left over is then disposed of as tailings. “Most of what we are mining is…
