Rare Earth Elements and Yttrium in Wyoming - From Oddities to Resources ? - 1991

Rare Earth Deposits & Mining

King and Hausel reported in 1991 that only minor amounts of rare earth elements and yttrium have been mined in Wyoming, but potential exists for future development within the state. At least 2 tons of rare earth-­bearing minerals were shipped from the Platt pegmatite mine in Carbon County in the late 1950s.

Exploration in the state was originally an outgrowth of exploration for thorium ores in the early 1950s. Early exploration focused on:

1. Tertiary carbonatites in the southern Bear Lodge Mountains;
2. Scattered, small Precambrian pegmatites, and veins, and carbonate pods;
3. Cambrian placer deposits on Bald Mountain in the Bighorn Mountains; and
4. Mesozoic titani­ferous black sandstone placer deposits.

The Bear Lodge carbonatite complex, the largest prospect in the state, has been examined as a large-tonnage, low-grade, porphyry-like deposit. To date, the rare-earth mineralization found in Wyoming and as of 1991 is not economic if the only products are rare-earths and yttrium. However, several potential co-products or by-products are present with the rare-earth deposits at each of the mineralized sites in the state. These include: gold, niobium, titanium, black metallic sand for coating pipes, phosphate, stron­tium, barium, ceramic-grade feldspar, fluorine, zirconium, and thorium.