Pajarito Mountain

Location: New Mexico, United States (33.237, -105.424 approx.)

Commodities: zirconium; rare earth elements

Deposit model: alkaline intrusions · unclassified

Geology

“Molycorp has announced a recoverable resource of 2.7 million tons with a grade of 0.18% Y2O3 and 1.2% ZrO2. Yttrium and zirconium will be recovered from eudialyte: (Na,Ca)5(Zr,Fe,Mn)(Si6O17) (O,OH,CI), Vlasov (1966). Eudialyte is disseminated as a rock-forming mineral in syenites, quartz syenites, and alkali granites. Ore-grade material occurs at the surface and it extends beyond the areas drilled. The deposit will be developed by open-pit mining methods and the ore will be processed on site.” (Sherer (1990)) “Precambrian alkaline rocks crop out in secs. 25 and 36, T12S, R15E and secs. 30 and 31,T12S, R16E (Fig. 1). Several varieties of syenite, quartz syenite, and alkali granite have been identified. Kelley (1968) reported ages ranging from 1,135 to 1,215 m.y. and Moore and others (1988) obtained an age of 1,150 m.y. for these rocks. All alkaline rocks analyzed by Molycorp and by Moore and others (1988) have alkalies K2O + Na2O in excess of Al2O3. Essential minerals are K-feldspar, albite, quartz, and Na-amphibole. No feldspathoids have been observed. Eudialyte is the most abundant of the unusual and rare minerals found at Pajarito. Others include zirconium silicates, lanthanide minerals, and several yttrium-bearing phases. Precambrian rocks are overlain by the Lower Permian Yeso Formation and San Andreas Limestone. Coarse clastic units of the Yeso Formation contain weathered fragments of Precambrian alkaline rocks. Sills and narrow dikes of olivine basalt intrude the Precambrian alkaline rocks. A few narrow dikes of basalt intruding San Andreas Limestone have been exposed in road construction.” (Sherer (1990))

Published resource estimates

As compiled by USGS USMIN from the cited studies. Resource classes follow the source; "approximate" flags values USMIN reports as approximations. These are not current company reserve statements.

Exploration and site history

• Exploration — Molycorp samples the Pajarito Mountain area under prospecting permits from the Mescalero Apache Tribe in 1984, 1984 (Sherer (1990))
• Discovery — Discovered through subsequent geological mapping, geochemical surveys, mineralogical studies, and metallurgical tests that were drilled in late 1985, 1985 (Sherer (1990))
• Exploration — Molycorp geologists sampled the area on July 4, 1983 as part of a survey of alkalic-rock complexes in the western U.S., 1983 (McLemore (1990))
• Discovery — Discovered in 1984, 1984 (Jackson and Christiansen (1993))

Record imported from USGS USMIN ver. 4.0 (June 2019). Developments after that date appear on facility records, not here; see the methodology.