Somewhere in the Earth’s crust a hot fluid is seeping through tiny cracks and fissures in the rock. The fluid is water and it carries with it a cargo of dissolved ions like chloride, sulfate, or carbonate. It might also carry dissolved metal ions useful to humans such copper, gold, or, in the case that we are considering, rare earth elements (REE). Fluids like this play important roles in forming ore deposits where the REE are present in high enough amounts to be mined. We want to understand how the REE interact with other dissolved ions and the water itself in order to better understand the conditions that allow water to mobilize, transport, or deposit REE.
The Point Lookout Sandstone on the Jicarilla Apache Reservation in Rio Arriba County contains geological layers called “beach placer deposits”. Beach-placer sandstone deposits are accumulations of dense minerals that form on beaches, or in shallow ocean water. They form by mechanical settling of heavy minerals by the action of waves, currents, and winds. These deposits contain Rare Earth Elements (REE) which are important commodities required to manufacture green technologies, like wind turbines and hybrid/electric cars and are essential in most of our electronic devices, like cell phones and laptop computers.
The NMBGMR has been examining the environmental effects of mine waste rock piles throughout New Mexico since the early 1990s. There are tens of thousands of inactive or abandoned mine features in 274 mining districts in New Mexico (including coal, uranium, metals, and industrial minerals districts), however many of them have not been inventoried or prioritized for reclamation. The New Mexico Abandoned Mine Lands Bureau of the New Mexico Energy, Minerals and Natural Resources Department estimates that there are more than 15,000 abandoned mine features in the state. The U.S. Bureau of Land Management recently estimated that more than 10,000 mine features are on BLM lands in New Mexico and only 705 sites have been reclaimed. The U.S. Park Service has identified 71 mine features in 7 parks in New Mexico, of which 12 have been mitigated and 34 require mitigation. Additional sites have been reclaimed by the responsible companies and the Superfund program (CERCLA).
The New Mexico Bureau of Geology and Mineral Resources has collected published and unpublished data on the districts, mines, deposits, occurrences, and mills since it was created in 1927 and is slowly converting historical data into a relational database, the New Mexico Mines Database. More than 8,000 mines are recorded in the New Mexico Mines Database and more than 7,000 are inactive or abandoned. These mines often include two or more actual mine features. Past funding has been from the Army Corps of Engineers, the New Mexico Abandoned Mine Lands Bureau of the New Mexico Energy, Minerals and Natural Resources Department, and EPSoR (Experimental Program to Stimulate Competitive Research; http://archive.nmepscor.org/). Some of this project is now funded under the U.S. Geological Survey EARTH MRI program (Earth Mapping Resources Initiative (Earth MRI) | U.S. Geological Survey (usgs.gov).
The Steeple Rock district in the Summit Mountains in southwestern New Mexico and southeastern Arizona offers an excellent opportunity to examine the relationship between the distribution and timing of the alteration and the formation of fissure veins in an epithermal environment. Five distinct types of epithermal veins occur in the district: base metals with gold-silver, gold-silver, copper-silver, fluorite, and manganese. These epithermal veins are structurally controlled, are hosted by Oligocene to Miocene volcanic and intrusive rocks, and are spatially associated with two types of alteration: neutral pH (alkali chloride or propylitic to argillic to sericitic) and acid sulfate (advanced argillic). Neutral pH alteration is the most pervasive type of alteration in the district and occurred in three stages: regional pre-mineralization, local syn-mineralization, and regional post-mineralization.
At the forefront of cutting-edge research at New Mexico Tech, we have been utilizing Raman spectroscopy to unravel the mysteries locked within minerals. By harnessing the power of visible and ultraviolet lasers, we can unlock a plethora of information. So, you may be asking, what is Raman spectroscopy? In simple terms, it's a technique that uses laser light to interact with the atomic vibrations of a material, producing a unique "fingerprint" of its molecular composition. By analyzing the scattered light, we are able to identify and characterize minerals such as apatite, fluorite, and calcite.
Although no uranium mines are operating in New Mexico today, the legacy of the mining industry requires continuing evaluation and remediation of inactive or abandoned mine features, which number around 300 for the uranium industry alone. The sites of mining activities can offer physical and chemical threats to individuals, communities and the environment. Dr. Virginia McLemore has assembled a team of New Mexico Tech students to evaluate mine sites throughout New Mexico as part of the Abandoned Mine Lands Project.
The recent discovery of manganese oxides on Mars suggests more oxygen was present in the Martian atmosphere the originally thought. A pilot project was recently funded by NASA to test the feasibility of discovering biosignatures in manganese deposits on Mars with payload instruments. There are two primary goals for this project; the first is to identify key chemical signatures and second to identify key mineralogical signatures in natural biologic and abiologic manganese materials. The pilot project will focus on three field sites in New Mexico that display features of formation that range from at or near the surface then extend to the deeper subsurface; essentially examining manganese deposits from surface, cave, geothermal springs, finally fossil hydrothermal environments. Should sufficient variation be noted during the pilot project, additional funding to the project will further characterize terrestrial occurrences for comparison to Mars by utilizing rover payload instruments
The Hillsboro district, in central New Mexico, is an example of the typical geologic style of the development of Laramide porphyry copper deposits in southwestern United States. Porphyry copper deposits form from hydrothermal fluids that come from a magmatic source, generally a volcano. The copper is concentrated first by magmatic-hydrothermal processes, then copper can be further concentrated by later supergene fluids, typically meteoric waters. Porphyry copper deposits typically are large deposits and are mined mostly by open pit methods and can have by-product production of gold, silver, molybdenum, and other metals. Other types of deposits, such as skarns and polymetallic veins can occur near the porphyry copper deposits. Much of the world's copper is produced from porphyry copper deposits.
The MINES Thermodynamic Database is an initiative to generate a revised internally consistent thermodynamic dataset for minerals, aqueous species and gases for simulating geochemical processes at hydrothermal conditions in the upper crust (≤5 kbar and ≤600 °C) with focus on ore forming processes.
As part of the Earth MRI project “Geochemical reanalysis of NURE samples from the Colorado Plateau, New Mexico, Utah, Colorado, and Arizona” (G23AC00561), New Mexico is resampling geologic material, including stream sediments and rocks, in the Zuni Mountains, Cibola and McKinley Counties. The purpose of this sampling is to assess the critical minerals potential of this area, which was historically mined for fluorspar and base metals. An exploration geochemistry focused class was taught in the fall semester of 2023. Sampling in the Zuni Mountains was conducted primarily by this class which allowed 17 students with varying field experience to learn how to plan and execute a sampling program. The students were split into five groups to sample different areas within the Zuni Mountains.