New Mexico Geological Society Annual Spring Meeting — Abstracts

The importance of Critical Minerals (CM) is vital to the U.S. economy, national security, and technological advancement. These minerals, such as tellurium, bismuth, molybdenum, and rare earth elements, play a key role in manufacturing products like smartphones, electric vehicles (EVs), solar panels, and military equipment. With the advancement of society, the race for CM increases. The Organ NM Mining District, founded in 1847 and operated until the 1930s, has many commodities of great necessity (K. C. Dunham et al., 1935). This district is in the Organ Mountains in Dona Ana County, New Mexico, 13 mi (20 km) east of Las Cruces, and has mineralization of interest. This mining district believed to have been established as the southwestern U.S. porphyry copper belt generally attributed to the Laramide Oregeny (40-80 Ma in age; Barton, 1996; Keith and Swan, 1996) magmatism and compressional deformation, which extended as far eastward as south-central New Mexico, as evidenced by the Copper Flat igneous complex and porphyry copper deposit near Hillsboro (McLemore et al, 1999, 2000b) and volcanic-clastic conglomerates in the McRae and Love Ranch Formations in the Jornada del Muerto near Truth or Consequences (Chapman-Fahey, 1996; Seager et al. 1997).

This mining district sits south of the San Andreas Mountains and north of the Franklin Mountains. Some of the principal mines that once operated in the district of the Organ Mountains were the Memphis Mine, Torpedo Mine, Rikardite, Hilltop Mine, and Stevenson Bennett, contributing to the amount of 15 million pounds of lead, 4 million pounds of copper, and almost 1 million pounds of zinc in its early stages of production. Giving two stages of production stints of mining activity within the mining district the first stage around 1900 to 1909, when a total of $927,836 worth of ore was produced; the second stage came around 1935 totaling $2,500,000 worth of base and precious metals (Seager,1981). In the 1980s, Conoco Inc. drilled near the Organ, N.M. for a porphyry copper deposit due to the poly metallic mineralization of copper, lead , and silver in the region. The drill log data collected during this drilling project totaled 17 boreholes, reaching a penetration depth as far as 5,000 ft in some boreholes. The chemical assayed data present is for Copper (Cu), Lead (Pb), Zinc (Zn), Molybdenum (Mo), Bismuth (Bi), Gold (Au), and Silver (Ag), followed by multivariate analysis. The Stevenson Bennette mine was home for one of New Mexico’s localities with fine Wulfenite mineral specimens. This study revisits this historic mining district by sampling tailings and dump materials from past operations, with the goal of identifying critical minerals that may have been overlooked in earlier assessments and to reclassify the district as a younger porphyry moly system. Additionally, the study aims to reclassify the district as a younger porphyry molybdenum system, formed not during the Laramide orogeny but as a result of extension and slab rollback associated with the Rio Grande Rift. Samples were submitted for multi-chemical analysis to obtain detailed compositional data. The results of the analysist, alongside historical data, reveal the presence of critical elements such as tellurium, molybdenum, bismuth, and rare Earths, which are increasingly recognized for their importance in contemporary technologies. By integrating old mining data with current methodologies, this study underscores the potential of historic mining districts as untapped resources for critical minerals that appear to be younger in age than that of the Laramide Orogeny since the region is 32.8 million years old. The findings highlight the significance of further exploration in these areas and suggest that more efficient extraction technologies may unlock valuable deposits previously deemed unworthy of extraction in this young deposit.

pp. 120-121