Rare Earth Mining and Exploration in North America

The occurrences of rare earth elements (REEs) in North America are abundant and diverse in mineralogy and geology. The Mountain Pass carbonatite in California historically has been a major world source for the light REEs. Monazite sands have also been mined on a moderate level in the southeastern United States. Fluids released from the mining of uraninite at Elliot Lake, Ontario, were intermittently a source for yttrium. Peralkaline igneous rocks in several areas of North America are currently under exploration for the entire REE spectrum, with emphasis on the heavy REEs. Although many REE occurrences contain a substantial tonnage of REEs, amenability to mineral processing and extraction of the REEs must be definitively established in each case.