New Mexico Geology

Deposits of rare earth elements (REE) are located in New Mexico, but they have not been important exploration targets in past years because demand has been met elsewhere. However, with a projected increase in demand, New Mexico deposits are being re-examined for their REE potential. REE-Th-U veins are found in the Gallinas, Capitan, and Cornudas Mountains and Laughlin Peak-Chico Hills; all are associated with Tertiary alkaline to alkalic-calcic igneous rocks. A small amount of bastnaesite, a REE mineral, was recovered during processing of fluorite mined in the Gallinas Mountains. Resources in the Gallinas Mountains amount to at least 537,000 short tons of 2.95% total REE. Four types of deposits are found in the Gallinas Mountains: epithermal REE-F veins, Cu-REE-F veins, REE-F breccia pipes and iron skarn deposits. The abundance of REE and other unusual minerals in the Cornudas Mountains suggests that the area has potential for undiscovered deposits of REE, niobium, and zirconium. U.S. Borax sampled and drilled in the Chess Draw area and found up to 0.06% total REE in samples. Other types of REE deposits in New Mexico include carbonatites in the Lemitar and Chupadera Mountains, Laughlin Peak- Chico Hills, Lobo Hill, and Monte Largo (Sandia Mountains). Disseminated Y-Zr deposits in Proterozoic syenite and nepheline syenite are known at Pajarito Mountain on the Mescalero Apache Indian Reservation near Ruidoso, where one sample contained 6,869 ppm total REE. In 1990, Molycorp, Inc. reported historic resources of 2.7 million short tons grading 0.18% Y₂O₃ and 1.2% ZrO₂ as disseminated eudialyte. The U.S. Bureau of Indian Affairs drilled five holes in 2014 and results are pending. Two additional deposit types have potential for REE in New Mexico: (1) Cretaceous heavy mineral, beach-placer sandstone deposits and (2) pegmatites. Drilling of one of these deposits, the Apache Mesa (formerly the Stinking Lake) beach-placer sandstone deposit in the Jicarilla Indian Reservation is expected to occur in the fall of 2015. Exploration has occurred in the Lemitar, Gallinas, and Cornudas Mountains for hydrothermal vein deposits. Many challenges, including permitting, face these industries in supplying REE elements. Most REE deposits are radioactive, although they contain less uranium and thorium then uranium mines, but will require special handling of the mine waste. Future development of these commodities will be challenging and more research is required to fully understand the REE potential in New Mexico.