149-1 Microbial Communities in Legacy Mine Waste in New Mexico: New Sites and Expanded Methods

Session: Research to Accelerate Recovery of Critical Minerals from Primary and Secondary Resources (Posters)

Poster Booth No.: 269

Presenting Author:

Melina Karavousanos

Authors:

Karavousanos, Melina Christine¹, Best, Mackenzie Brown², McLemore, Virginia T.³, Jones, Daniel S.⁴

(1) Earth and Environmental Science, New Mexico Institute of Mining and Technology, Socorro, New Mexico, USA, (2) New Mexico Tech, Socorro, NM, USA, (3) Bureau of Geology, Socorro, NM, USA, (4) New Mexico Tech/NCKRI, Socorro, NM, USA,

Abstract:

Critical minerals are any non-fuel material that has a high-risk of supply chain disruptance, and there is a push to evaluate alternative sources for these elements such as in non-traditional deposits and pre-existing mine wastes. New Mexico has a rich mining history with many legacy sites across the state, many of which contain waste rock, tailings, and other leftover materials that still contain critical minerals. In this project, we are investigating the microbial communities that have developed since these mine wastes were emplaced in order to understand their composition and how microbes might interact with residual minerals in the deposits. In previous work by some members of our group, we evaluated the geomicrobiology of historic mine waste from five locations in three mining districts, and found that microbial communities varied by waste type and region, with some of the most abundant populations represented undescribed microorganisms. In this work, we are expanding these efforts to several new locations that represent a more diverse array of waste types, including waste rock and tailings from carbonate-hosted mineral deposits. We are combining cell counting, rRNA gene and transcript sequencing, and whole rock geochemistry with metagenomics and culture-based analyses to continue to evaluate the relationships among microbial communities and geochemical variables, and to explore the metabolic capabilities of the many novel populations in these deposits. Results to date from 16S rRNA gene libraries show that the deposits contain diverse bacteria including abundant Actinobacteriota, Alpha-, and Gammaproteobacteria, along with archaeal populations such as unclassified Nitrososphaeraceae and “Candidatus Nitrososphaera.” Preliminary metagenomic libraries indicates the presence of autotrophs and genes associated with some lithotrophic metabolisms such as ammonia oxidation, but confirms previous indications that microorganisms capable of oxidizing inorganic sulfur or iron compounds are rare. We will discuss ongoing exploration of the novel populations in these deposits, and implications for the biogeochemistry of legacy mine waste and possible microbial approaches to critical mineral recovery. 

Geological Society of America Abstracts with Programs. Vol. 57, No. 6, 2025

doi: 10.1130/abs/2025AM-10668

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