Research Mission critical: To get critical minerals and rare earth metals from coal waste Pennsylvania’s mine waste could play an important role in the nation’s green-energy future. The U.S. Geological Survey (USGS) currently designates 50 minerals as critical to the U.S. economy or its national security or both. That number includes the so-called rare-earth elements — the 15 lanthanide metals at the bottom of the periodic table plus scandium and yttrium — along with the battery metals lithium, cobalt, nickel, and manganese, as well as platinum, aluminum, and graphite, among others.

https://www.psu.edu/news/research/story/mission-critical-get-critical-minerals-and-rare-earth-metals-coal-waste