Text Size  A  A   Twitter Facebook YouTube Instagram Sign Up For Email Updates

Wyoming's Rare Earth Elements



Download Report

The most recent study on rare earth elements (REE) in Wyoming, WSGS Report of Investigations No. 71, 2016, is a comprehensive report of past WSGS work as well as additional data gathered in 2015. The goal for RI-71 was to provide further geological analysis, beyond our previous RI-65, on potential deposits and to characterize and catalog these deposits found throughout Wyoming. This, as well as past publications, are available on the WSGS website.

“Our investigation of REE in Wyoming has identified various geologic environments in the state in which they occur,” says Wayne Sutherland, WSGS gemstones, metals and economic geology specialist. “This study has also provided publicly accessible chemical analyses across Wyoming, which may aid companies and prospectors in their search for economic deposits of other types.”

Rare earth elements are vital to industrialized societies worldwide. REE are a group of 17 chemicals that occur together in the periodic table. Sixteen of these occur in nature and are typically found in varying proportions in the same ore deposits. Also called rare earth metals, they are used to produce a range of sophisticated technological products such as nuclear reactor components, cell phones, magnets, camera lenses, and batteries.



Supplemental Data





REE Background

Eastern Wind River Basin.

What are Rare Earth Elements?

REE are a group of 17 metallic elements with similar physical and chemical properties that occur together in the periodic table. Sixteen of these occur in nature and are typically found in varying proportions in the same ore deposits. REE are vital to industrialized societies worldwide as they are used in a range of products, including nuclear reactor components, cell phones, magnets, camera lenses, and batteries.

During the last 15 years, REE production and processing have centered in China, which by 2010 provided 95 to 97 percent of the world’s supply. When China reduced REE exports by 40 percent in 2010, as compared to 2009, world demand exceeded the supply. This inspired heightened REE exploration and development by other countries to meet demand and offset the elevated price. Molycorp’s Mountain Pass Mine in California reopened in 2010 and increased the United States’ supply for a short time. However, its 2015 closure and China’s stronghold on global supply has continued driving interest in securing REE resources to maintain U.S. national security.

World Deposits and Reserves

The largest known REE deposits occur in China, Australia, and North America, with much smaller reserves found in India, Brazil, Malaysia, and South Africa. Production has been dominated by China, with additional production from Australia, India, Malaysia, Russia, and Thailand. China's reserves are the largest. Estimates project that China has the largest percentage worldwide of REE reserves at about 36 percent, compared to the United States at about 13 percent. The Commonwealth of Independent States (Azerbaijan, Armenia, Belarus, Georgia, Kazakhstan, Kyrgyzstan, Moldova, Russia, Tajikistan, Turkmenistan, Uzbekistan, and Ukraine) controls about 19 percent, followed by Australia with more than 5 percent and India with 3 percent.

Current U.S. Production

As of June 2016, there is no mining or production of REE in the United States. According to the U.S. Geological Survey, deposits of REE-bearing ore exist in California (Molycorp Mountain Pass mine), Nebraska, Colorado, New Mexico, Texas, New York, Alaska, and Wyoming.

Mining was in the planning stages for one major Wyoming REE deposit in the Bear Lodge Mountains in Crook County. Unfortunately, weak market conditions and a lengthy permitting process caused Rare Element Resources, Ltd. to temporarily suspend the project as of January 2016. The potential exists for the occurrence of additional REE deposits across the state.

Geology and Minerals

Euxenite Platt Mine.

Awareness of the diversity of REE deposit types is beneficial to exploration efforts. Economically, exploitable concentrations of REE are primarily derived from crystalline rocks. REE are more common in alkaline igneous rocks and carbonatites than in mafic rocks. Rare earths typically occur as trivalent cations in rock-forming minerals in carbonates, oxides, phosphates, and silicates. REE are chemically similar to thorium and are often found in minerals and rocks in association with this element. Economic concentrations of REE host minerals are known from alkaline igneous rocks, carbonatites, and from a wide variety of dikes and veins that cross-cut alkaline intrusions and surrounding rocks.

REE occur in a variety of rock units across Wyoming. Reported Precambrian REE occurrences are hosted by pegmatites, veins and dikes, faults and shear zones, metacarbonate rocks, disseminated minerals in generally alkalic igneous rocks, and metasediments. Sedimentary occurrences in paleoplacers are found primarily in the Cambrian Flathead Sandstone and the Cretaceous Mesaverde Formation as well as local, smaller deposits in numerous units. Disseminations of REE are also reported within phosphate-rich rock of the Permian Phosphoria Formation. Tertiary-aged hosts include alkaline igneous rocks, carbonatite veins, dikes, hydrothermal zones, paleoplacers, and apparent depositions from solution movement within sandstones. Quaternary REE hosts can be found in alluvial placers and paleoplacers (King and Harris, 2002; Sutherland and others, 2013).

Numerous minerals are known to contain REE as essential constituents, and a greater number contain REE as accessory elements. Only a few of these minerals host large enough concentrations of REE to be considered ore minerals. Allanite and monazite occur as relatively common accessory minerals within many types of felsic igneous rocks. Other REE-bearing minerals can be uncommon and are often hosted in generally uncommon rock types. Worldwide, the principal commercial sources of REE are the minerals bastnasite, loparite, monazite, and xenotime, and rare earth ion-adsorption clays. When discussing principal REE-bearing minerals specific to the United States, Long and others (2010) omit loparite and ion-adsorption clays but add euxenite and allanite, although other REE-bearing minerals are also present.

Of the principal REE-bearing minerals, allanite, bastnasite, euxenite, monazite, and xenotime are known to occur in Wyoming. Ewaldite and mckelveyite, although not primary REE sources, were actually discovered with association to trona beds in the Green River Formation in Sweetwater County. The table below lists minerals reported in Wyoming that contain REE. Mineral formulas are variable depending on the source cited and on subvarieties that may contain differing elemental substitutions.


Download Table
REE-bearing minerals that occur in Wyoming.

REE Uses

Tie Siding Pegmatite.




Consumer products that rely on integral use of REE include catalytic converters, cell phones, digital cameras, and computers. Additionally, neodymium, samarium, gadolinium, dysprosium, and praseodymium are used in high-power permanent magnets where weight and space are of concern. These applications range from computer hard drive motors and MRI scanners to wind generators. A typical hybrid car, such as a Toyota Prius, contains around 11.3 kg (25 lbs) of REE, mostly lanthanum, in its rechargeable battery and about 2 kg (4.5 lbs) of neodymium and dysprosium in its drive motor. Smart phones and LED lights each contain less than a gram of REE (Molycorp, 2015a).

REE are also used for national security purposes. The U.S. Department of Defense uses REE in lasers, precision-guided munitions, communications and radar systems, avionics, night-vision equipment, satellites, range finders, and control systems. These security-related uses make China’s control of REE a subject of concern to many nations.


Download Table
Typical uses of the rare earth elements.





Contact:
Wayne Sutherland (307) 766-2286 Ext. 247