Compilation of mafic and ultramafic mine waste data in the United States for surface-based CO₂ mineralization resource assessments

This data release is a compilation of information from historically mined sites in the United States that are confirmed or inferred to have generated mafic to ultramafic mine waste. Waste rock and milled tailings from the mining of mafic to ultramafic ores are prospective surface-based feedstocks for CO₂ mineralization given their high specific surface area and CO₂-reactive mineralogy. Additionally, such wastes commonly contain elevated critical mineral concentrations, such as nickel and cobalt, in CO₂-reactive host minerals such as olivine and serpentine minerals. The U.S. Geological Survey (USGS) received direction from the U.S. Congress to identify sources of alkalinity and their CO₂ mineralization potential (U.S. Congress, 2024) and from the Department of the Interior, via Secretarial Order 3436, to identify opportunities to recover critical minerals from mine wastes (Department of the Interior, 2022). As part of assessing these resources, the USGS has identified 1298 sites that were historically mined for commodities hosted in mafic-ultramafic rocks, namely nickel sulfide, platinum group elements (PGE), serpentine asbestos, podiform chromite, and olivine, which may be prospective for mine waste suitable to CO₂ mineralization. Data were integrated from multiple sources, including the USGS Mineral Resources Data System (MRDS), USGS Alaska Resource Data File (ARDF), USGS Open File Reports, specialized mineral deposit databases, industry reports, and refereed articles to characterize the historical production of mine waste at these sites. Where reported, the data release represents a compilation of site-level data of tailings masses, tailings volumes, ore production masses, commodity production masses, ore grades, and production size classes. Reported tailings mass or volume data exist for only 1% of sites (n=13), typically at the largest mining operations, reflecting data limitations among small-scale operations. Reported ore production, commodity production, and/or ore grade data are reported for 511 sites, and generalized production size classes were assigned for the remainder of sites based on reported production or other available information. Sites were not directly investigated to confirm the presence and accessibility of historically produced mine waste, to identify historical site remediation, or verify current conditions of tailings storage. However, the storage setting of tailings (tailings pond, pile, remediated/capped, etc.) for some of the largest sites was confirmed using published reports. These data form an input dataset for the USGS National Assessment of surface-based CO₂ mineralization resources and may support related USGS Earth Mapping Resources Initiative (Earth MRI) efforts to catalog and characterize mine waste in the United States.
References:
U.S. Congress, 2024, Congressional Record, 118th Cong., daily ed., Senate, Mar. 5, 2024, p. S1679.
Department of the Interior, 2022, Unlocking Critical and Strategic Minerals from Mine Waste, Cutting Red Tape, and Restoring American Dominance in Strategic Mineral Production: Secretarial Order No. 3436, available at https://www.doi.gov/sites/default/files/document_secretarys_orders/so-3….