Sutherland, Gregory, Carnes, and Worman of the Wyoming Geological Survey reported in 2013 that rare-earth elements (REE) comprise a group of metals with similar physical and chemical properties that encompasses the lanthanide series elements plus scandium and yttrium. Sixteen REE occur in nature, however, promethium (Pm) is highly unstable and occurs in very, very low concentrations on Earth.
Diverse sectors of the U.S. economy depend upon REE, including energy generation, transportation, data transmission, and national defense. Despite domestic demand for REE, the United States has produced negligible REE since the early 2000s, while China has accounted for 90 to 97 percent of the global supply.
Current U.S. production is increasing due to the reopening of Molycorp’s Mountain Pass mine in California, the only active REE mine in the country. Exploration and development of new prospects across the United States is on-going and includes the Bear Lodge deposit in northeastern Wyoming, owned by Rare Element Resources, Ltd. The Bear Lodge deposit was not part of Wyoming State Geological Survey (WSGS) field investigations since it is currently under intense exploration by private interests.
Previous investigations identified many potential REE occurrences in Wyoming, but lacked complete elemental analyses. The WSGS collected samples from numerous known, suspected, and potential REE host rocks and analyzed them for REE content as well as for other potential economic metals or elements. The limited timeframe for this project precluded collecting samples from all known or potential REE-hosting sites, however, the WSGS collected a large number of samples. Notable REE enrichment occurs in a variety of geologic environments across Wyoming. These environments include carbonatites, pegmatite pods and lenses, epidosite dikes, calc-silicate pods and dikes, iron-rich silicate pods, paleoplacers in marginal marine sandstones, and phosphatic horizons in marine shales and lacustrine mudstones. For widespread access to the results of this study, the WSGS has developed an online database that contains locations, geologic settings, and analyses for all samples.
This database will aid mineral exploration across the state, by identifying not only REE concentrations, but other potentially economic elements and related associations as well.
Managed & Built by I2M Consulting, LLC | © 2010-
