Funding Agency: Department of Energy
Total Funds: $1,999,942
Lead Researcher: Jared Freiburg, Ph.D.
Project Duration: 9/30/21–8/31/24

The Illinois Basin CORE-CM project will evaluate the domestic occurrence of strategic elements in coal, coal-based resources, and waste streams from coal use in the region of the Illinois Basin. Led by the Illinois State Geological Survey, the project team consists of the state geological surveys of the Illinois Basin, regional universities, national laboratories, and industries active in the region.

The project’s goals include:

A basin-wide assessment of CORE-CM in coal, coal-based, and waste stream resources including availability and abundance. R&D projects for innovative waste stream technology development.
Assess regional infrastructure, industries, and businesses to integrate and leverage regional attributes to spur economic growth by utilizing the basin’s CORE-CM.
Technology assessment, development, and field testing. Identify innovative mining, processing, and separation techniques for CORE-CM. Develop innovative technologies to incorporate coal and coal waste-derived CORE-CM into high-value products
Develop Technology Innovation Centers to address and accelerate research to enable commercial deployment of Illinois Basin CORE-CM resources. Centers will focus on advanced analytics, processing, and production of CORE-CM and high-value, nonfuel, coal products. Centers will offer advanced opportunities for education and training of the next generation of technicians, skilled workers, and STEM professionals. Centers will support public-private partnerships to advance innovative technology development and new product production.
Develop a strategic stakeholder, outreach, and education program to support CORE-CM economic development activities. Development of best practice manuals, education and training guides, and explore potential collaborations with R&D projects funded by DOE to expedite technology transfer.

Funding Agency: Department of Energy
Total Funds: $5,000,226
Lead Researcher(s): Jared Freiburg, Ph.D. and Charles Bopp, Ph.D.
Project Duration: 08/01/2024–11/30/2025

The Illinois Rare Earth Novel Extract & Supply (IRENES) project will design a system to use the mine waste of the last industrial revolution to provide a domestic supply of critical minerals (CM) to enhance the competitiveness of the United States, drive the creation of good paying union jobs, tackle the climate crisis, and ensure access to economic benefits to disadvantaged communities. Led by the Illinois State Geological Survey at the Prairie Research Institute (PRI), part of the University of Illinois Urbana-Champaign, the IRENES project seeks to perform the Front-end Engineering and Design (FEED) needed to establish a fully integrated, vertical supply chain for several critical minerals that would be located entirely within the State of Illinois. The objective is to bring Lithium, Scandium, Neodymium, and Praseodymium, metals; as well as high-purity Dysprosium and other Rare Earth Element (REE) oxides and Nickel, Zinc, Cobalt, Manganese, and potentially high-purity Aluminum to market. The proposed engineering study envisions three key facilities, each specifically responsive to DoE requirements in whole or in part. An extraction facility to be located in Marissa, IL at the Prairie State Energy Campus, a combination coal mine and coal-fired power plant complex. A concentration and production plant is envisioned near the same facility to produce Mixed Rare Earth Oxide (MREO), scandium, and other CMs. Finally, a purification and refining facility would be established in Urbana, IL to produce refined, individual REE oxides and metals (via electrowinning and metallothermic reduction) from the MREO. The project envisions up to 50 tons per year of MREO production, plus purified individual REE, scandium, and various CMs. The objective of the proposed project is to complete a FEED study based on AACE Class 3 cost estimates and specified engineering drawings and deliverables. The completed FEED will include the design and cost estimates for facilities that demonstrate the concentration and extraction of MREO from coal mine refuse and effluents and subsequently separation and refinement into REM. The outcome of the project will provide engineering plans for the facilities that include processes, design, performance, cost, gaps, life cycle analyses, and address environmental and social concerns. In addition to ISGS, the project team includes the University of Kentucky, Argonne National Laboratory, The Process Group, PLLC, Dynamic 3D Solutions, Sargent & Lundy, Koch Modular Process Systems, WSP Global, Prairie State Generating Company, and APL Engineered Materials Inc.

Funding Agency: Department of Defense
Total Funds: $2,000,000
Lead Researcher(s): Jared Freiburg, Ph.D., Charles Bopp, Ph.D., and Jarek Trela, Ph.D.
Duration: 9/1/24–3/2/26

Hicks Dome (HD) is a rare earth element (REE) enriched volcanic structure in southern Illinois containing one of North America’s largest untapped fluorspar resources and a surficial deposit of regolith enriched in important critical elements such as fluorspar (F) neodymium (Nd), niobium (Nb), praseodymium (Pr), dysprosium (Dy), and scandium (Sc) among other critical minerals. This study will develop a novel process technology at bench scale dedicated to continuous and sustainable extraction of critical minerals from HD. The process will be designed (with intention for rapid scaling to a pilot/commercial-scale facility) to sustainably produce raw critical minerals for clean energy technologies and national defense. This bench scale process will focus on innovative extraction and processing techniques specifically designed for feedstock from HD and the production of several critical minerals (CM), particularly Rare Earth Elements (REE). The project will seek to maximize efficiency of the feedstock and produce Mixed Rare Earth Oxide (MREO) and several CM products in a cost-effective and environmentally benign manner. The process will be developed around mineral liberation results from a detailed characterization plan to be completed to account for mineral variability across the deposit. In addition, a resource delineation will be completed to determine the shape, size and extent of the resource feedstock to support a resource model and economic evaluation. Based upon the developed process and the deposit economics, front-end engineering and design will be started for a scaled-up facility. This will include a techno-economic feasibility study, generalized facility engineering drawings, and site availability and screening. The overarching vision of this proposal is to develop a scalable process for the domestic production of CMs from a domestic conventional deposit. The success of this project would unlock a major source of critical elements in the U.S., particularly heavy rare earths, and provide economic revitalization to an impoverished region of the United States. This project will be led by the Illinois State Geological Survey with key collaborative partnerships including the University of Kentucky, The Process Group, and Hicks Dome LLC.

Lead Center Researcher: Franck R.A. Delpomdor, Ph.D.
Agency: U.S. Geological Survey
Program: Earth Mapping Resources Initiative
Total Award: $626,046
Project Duration: 3 years (09/01/2023–09/01/2026)

The Upper Mississippi Valley (UMV) Zn-Pb District is one of the largest base metal districts in North America and the type locality for Mississippi Valley-type (MVT) deposits. It covers more than 7,800 km2 in northwest Illinois, northeast Iowa, and southwest Wisconsin. The UMV Zn-Pb District in this area has produced over 1.5 million short tons of zinc and 500,000 short tons of lead. The resource was estimated to contain over 1 million short tons in place of zinc and lead. However, these unrecovered ores have been underestimated because of the lack of exploration using modern geochemical and geophysical methods. The ores contain 4% to 8% of Zn and 0.5% to 1% of Pb. Critical minerals of significance within the district include sphalerite and residuum associated with barite with the potential for other associated critical minerals. Although the MVT deposits in this district are relatively well studied, no reliable data are available on the distribution or the concentrations of critical minerals such as Zn, Ba, U, Cd, Ag, Ga, In, and Ge-bearing minerals within UMVT sphalerite ore, and associated barite ore. Several questions remain regarding the concentration of critical minerals, their variability, spatial distribution, and their overall paragenesis related to MVT mineralization. This project aims to sample MVT sphalerite and barite ores from outcrops and cores from across the UMV Zn-Pb District extended to the Quad Cities area for geochemical analysis and a comprehensive evaluation of their critical mineral contents. The Illinois State Geological Survey (ISGS) in collaboration with the Wisconsin Geological and Natural History Survey (WGNHS) and the Iowa Geological Survey (IGS) proposes to undertake three major tasks in support of the Earth MRI project to geologically map and characterize the focus area of the UMV Zn-Pb District in Illinois, Iowa, and Wisconsin. The area is extended to the Quad Cities area in Illinois and Iowa, which the MVT mineralization extends. These tasks have been dovetailed to create a significantly improved understanding of the UMV Zn-Pb District and provide crucial information for future critical mineral exploration. The three tasks are as follows:

1. Mapping of the UMV Zn-Pb District including historic mines, boreholes, mineralization, structural geology, and newly collected samples with geochemistry analysis; 2. New geochemical data as well as petrographic, mineralogic, and thermometric results, driven by the newly created map, will be used to fill data gaps and to define a better sampling strategy of minerals for resource assessments of critical minerals in the district; 3. An ESRI file geodatabase including all data and a supplemental report that includes a high-level geologic interpretation that will provide context to the data. ISGS will deliver an ArcGIS database, a map of all georeferenced historic mines, boreholes, mineralization, structural geology, and newly collected samples with geochemical data of the UMV Zn-Pb District, and a report. All data will be published in the report by ISGS within 2 years of delivery to the USGS. This Earth MRI project will provide an opportunity to deliver unbiased information of unknown mineral resource potential in a region that has been largely mined for lead and zinc ores but in which the critical minerals such as Zn, Ba, U, Cd, Ag, Ga, In, Ge, and Rare Earth Elements have not been studied for their potential resource. This Earth MRI project will be conducted in partnership with the WGNHS and IGS.

Lead Center Researcher: Franck R.A. Delpomdor, Ph.D.
Agency: U.S. Geological Survey
Program: Earth Mapping Resources Initiative
Total Award: $367,745
Project Duration: 09/01/2023–09/01/2025

The Upper Mississippi Valley (UMV) Lead-Zinc District is one of the largest base metal districts in North America and the type locality for Mississippi Valley-Type (MVT) deposits. It covers more than 7,800 km2 in northwest Illinois, northeast Iowa, and southwest Wisconsin. The UMV Lead-Zinc District in this area has produced over 1.5 million short tons of zinc and 500,000 short tons of lead. The ores contain 4% to 8% of Zn and 0.5% to 1% of Pb. A large volume of mine wastes rejected from the extraction of Pb and Zn ores forming mine, mill tailings, and rock piles across the UMV Lead-Zinc District. Remaining lead and zinc in some of these mine tailings piles gave high concentrations of lead (446 to 1,943 ppm) and zinc (3,502 to 20,088 ppm) but there is no reliable data available on the distribution or the concentrations of critical minerals such as Zn, Ba, U, Cd, Ag, Ga, In, and Ge-bearing minerals within MVT sphalerite ore, and associated barite ore. For this 2-year Earth Mapping Resource Initiative (EMRI) project, ISGS proposes to inventory and characterize UMV mine waste sites that may potentially contain critical mineral resources. The EMRI Mine Waste Cooperative Agreements G23AS00160 provides an opportunity to deliver unbiased information on unknown mineral resource potential, disposal volume, and environmental interaction in a region that has been largely mined for lead and zinc ores. Priority 1 National Mine Waste Inventory will collect, compile, and map existing data of UMV mine waste sites in Illinois and Wisconsin to provide the surface framework for future explorations of critical minerals. For Priority 2, ISGS has prioritized two mine waste sites in Illinois for their volume, geology, and potential resources: (1) the Bautsch-Gray Mine Superfund Site, and (2) the Little Giant Mine’s mine tailing pile. Mine waste materials will be collected following the newly created USGS Sampling Protocol for mine waste characterization efforts to standardize the sampling carried out by the state geological surveys. The samples will be analyzed for geochemistry and mineralogy to identify mine waste sites for their extraction of critical minerals in the future. Priority 3 is requested for two participants to attend the next Earth MRI workshop in October 2023. ISGS will deliver an ArcGIS database, a map of all georeferenced UMV mine waste sites, volume estimates of mine tailings piles, geochemistry, resource estimation, a report, and feedback provided by USMIN. All data will be published in the report by ISGS within 2 years of delivery to the USGS. This EMRI project will provide an opportunity to deliver unbiased information of unknown mineral resource potential, disposal volume, and environmental interaction in a region that has been largely mined for lead and zinc ores but in which the mine wastes have not been studied for their potential resource. This EMRI project will be conducted in partnership with the Wisconsin Geological and Natural History Survey.

Lead Center Researcher: Franck R.A. Delpomdor, Ph.D.
Agency: U.S. Geological Survey
Program: National Cooperative Geologic Mapping
Total Award: $1,385,527
Project Duration: 09/15/2023-09/14/2024

During the period from September 15, 2023, through September 14, 2024, the Illinois State Geological Survey will undertake high-resolution mapping of 4 quadrangles and revise and update areas previously mapped at lower resolution into modern digital data sets. The quadrangle mapping (1:24,000 scale) is most useful for local analyses, whereas the regional (~1:100,000 scale) and statewide (1:500,000 scale) compilations are suited to regional- to national scale analyses. Project 1 comprises two subprojects: the Bedrock geology of the Elizabeth and Scales Mound West Quadrangles, Jo Daviess County, northwestern Illinois, and the Bedrock geology of the Montpelier and Illinois City Quadrangles, Rock Island County, western Illinois. The mapping focuses on the occurrence of economic and industrial minerals, especially lead-zinc and phosphorite deposits which are sources of critical minerals for which there is high demand in electronics manufacturing. A 300-foot-deep drill hole will target the Lower Pennsylvanian rocks to update the Pennsylvanian stratigraphy and sedimentology between Illinois and Iowa. Project 2 proposes the start of a 5-year plan for the Greater Chicago region to create a 3D model framework of the surficial and shallow bedrock geology. Year 1 will involve compiling an engineering geology database and upper bedrock surfaces of Cook and DuPage Counties. The highly populated area includes large areas with impoverished communities, a legacy of industrial uses, and significant challenges posed by urban flooding. In Project 3, the Bedrock geology of Jackson and Randolph counties, southwestern Illinois, will be digitally compiled from 24 previously mapped quadrangles. The quadrangles, mapped by several different geologists over 3 decades, will be harmonized and edge-matched by revisiting key field outcrops. Understanding of the extinction event within the Mississippian Menard Formation where the last known occurrence of the Nautiloid Endolobus spectabilis will be traced by chemostratigraphy. Project 4 comprises two subprojects: the phase 4 compilation of the Illinois Statewide Surficial County maps and GeMS updates of previously published County Surficial Geology maps of Madison and St. Clair Counties. The proposed Phase 4 will extend mapping into northwestern Illinois and will address Quaternary state-border mapping into an area with complex surficial geology and uncertain correlations for Illinois Episode glacial till units. These Quaternary map compilation in the Phase 4 area were the culmination of several years of detailed 1:24,000 quadrangle mapping, funded in part by the USGS-STATEMAP program. However, GeMS standards have not been applied to these detailed county compilations. Electrical resistivity tomography will be used to help to delineate possible discontinuous eskers or moraines in areas of limited prior mapping. Quaternary geology maps of Madison and St. Clair Counties will contribute to understand important societal issues that include seismic hazards, sand and gravel resources, coal-mine subsidence, and groundwater contamination potential. Project 5 proposes a geophysical imaging survey to map a structurally complex deep aquifer system in north-central Illinois to determine the sustainability of a deep aquifer system in the presence of Sandwich Fault Zone. The geophysical survey will consist of high-resolution active and passive source seismic imaging as well as time domain electromagnetic method. Six of the 7 maps described above will be delivered to the U.S. Geological Survey as PDFs and in GeMS Level 3-compliant databases. In addition, the previously 26 published maps from Projects 1, 3 and 4 will be delivered as GeMS Level 3-compliant databases. The Statewide Surficial Geology will be a progress report for Phase 4 including GeMS Level 3 implementation. Project 4 will deliver a final report with describing seismic data interpretation and raw and processed seismic data files. The deliverables will be available from the Illinois State Geological Survey website soon after delivery, submitted to the U.S. Geological Survey National Geologic Map Database, and will be published within the ensuing year.

Lead Center Researcher: Franck R.A. Delpomdor, Ph.D.
Agency: U.S. Geological Survey
Program: National Cooperative Geologic Mapping
Total Award: $1,115,880

For FY2024, the Illinois State Geological Survey and the Illinois Geologic Mapping Advisory Committee prioritized 5 mapping regions — Northwest Illinois, Quad Cities, Greater Chicago, Wabash Valley, and Southern Illinois — for the evaluation of emerging needs for water supply and protection, infrastructure planning, natural resources, geologic hazards, and basic science. The bedrock geologic mapping will continue Illinois State’s effort that challenges us to identify new areas that may have the potential to contain undiscovered critical minerals and to develop carbonate aggregate production. The surficial geological mapping goals will contribute to new and ongoing societal concerns such as the implementation of green infrastructure, student opportunities, especially for minorities in south Chicago, characterization of earth materials impacted by near-surface contamination, flood and seismic zone planning, and deep drift groundwater management. For this USGS STATEMAP Program Announcement no. G24AS00043, ISGS proposes a 12-month mapping project starting from September 15, 2024, through September 14, 2025. The bedrock geologic mapping will include the Cordova and Bellevue 7.5′ quadrangles, Hamilton and White Counties (new mapping: Category 1, Guidance Criterion 1; Category 2, Guidance Criteria 5) (Project 1), and Jerseyville map compilation (Category 2, Guidance Criteria 4 and 5) (Project 3). The surficial geology will map Cook and DuPage Counties of the Surficial Geologic Mapping in Greater Chicago project: Phase 2 (Category 1, Guidance Criterion 1; Category 2, Guidance Criteria 3 and 5) (Project 2), and Statewide Surficial Geology (Phase 5) (Category 2, Guidance Criteria 4 and 11) (Project 4). Projects 1 and 3 mapping will focus on the occurrence of economic and industrial minerals, especially lead-zinc, barite, residuum, and Rare Earth Element-bearing deposits, as well as oil and gas exploration. Project 1 will contribute to delivering unbiased geologic information for abandoned mine land remediation, and the emergency management in seismically active areas along the Wabash Valley region. Projects 2 to 4 will deliver updating completed maps to GeMS compliance, transformation of previous STATEMAP map products to regional or statewide scales more suitable to framework syntheses, and radiocarbon database. Project 2 will include the surficial geologic mapping in Greater Chicago – Phase 2 to create a 3D model framework of the surficial and shallow bedrock geology; Year 2 will provide the USGS county-scale geologic cross sections based on well and boring inventory and new geophysical survey data of the Cook and DuPage Counties. Project 4 will work on the phase 5 compilation of the Illinois Statewide Surficial County maps and GeMS updates of previously published County Surficial Geology maps of Madison and St. Clair Counties. The proposed Phase 5 will extend mapping into Western Illinois and address Quaternary state-border mapping into an area with complex surficial geology. ISGS will submit to the USGS by September 14, 2025, the following as draft 1:24,000 scale PDF maps that include the Bedrock Geology of the Cordova 7.5′ Quadrangle (Illinois portion), Bedrock Geology of the Bellevue 7.5′ Quadrangle (Illinois portion), GeMS-compliant (Level 3) geologic map database of the Bedrock Geology Map of Hamilton County, Illinois, GeMS-compliant (Level 3) geologic map database of the Bedrock Geology Map of White County, Bedrock Geologic Map of the Jerseyville 30′ x 60′ compilation, GeMS-compliant (Level 3) geologic map geodatabase Bedrock Geologic Map of the Jerseyville 30′ x 60′ compilation, and GeMS-compliant (Level 3) geologic map geodatabases of 4 previously published, 1:24,000 scale, of the Bedrock Geology quadrangle maps from the Jerseyville 30′ x 60′ compilation. This STATEMAP FY2024 project will benefit from the expected outcomes for (a) the U.S. Environmental Protection Agency and Jo Daviess County local community by remediating toxic mining wastes in Northwest Illinois that can be the cause of health and environmental issues, (b) the Quad Cities aggregate companies (RiverStone Group, Inc.), (c) to complete.

Lead Center Researcher: Scott Elrick
Agency: U.S. Geological Survey
Program: Earth Mapping Resources Initiative
Total Award: $200,000
Project Duration: 3 years (08/01/2019–07/31/2021)

For phase I of Earth MRI, the USGS conducted airborne magnetic and radiometric surveys to map potential critical mineral deposits, hidden in the subsurface in southeastern Illinois. Phase I corroborated several known subsurface occurrences of igneous rocks and revealed numerous, previously unidentified anomalies that may contain critical minerals. ISGS used this valuable data to inform field mapping, studies, and geochemical/mineralogical investigations during Earth MRI phase II. Based on phase I USGS aeromagnetic data, ISGS collected over 200 new samples from the district that were analyzed for REE abundances.

Lead Center Researcher: Jared Freiburg, Ph.D.
Agency: U.S. Geological Survey
Program: Earth Mapping Resources Initiative
Total Award: $99,972
Project Duration: 2 years (09/21/2021–09/21/2023)

Under the auspices of the Earth MRI program, ISGS undertook three major tasks in support of this project to geologically map and geochemically characterize the Illinois focus areas of the Illinois-Kentucky Fluorspar District (IKFD) and the Permian Wauboukigou Igneous Province (PWIP). These tasks were completed, and data collected during the tenure of this project improved Illinois’ understanding of the two districts and provided crucial information for future critical mineral exploration. The three major completed tasks included:

“A compilation of data that will be provided to the Kentucky Geological Survey (KGS) to supplement a 3-D model of the IKFD and PWIP of which will be provided by KGS. This compilation will include subsurface, geophysical, and historical mine data.”
— ISGS completed a user-friendly tool that includes maps and data across the IKFD and MPUD and can be accessed through the free Esri ArcGIS Field Maps Application that can be utilized in the field to locate data in real-time.
Collection of new geochemical and mineralogical data, driven by the newly acquired geophysical data (magnetic and radiometric). This data was provided in a supplemental Access database.
A report that included a high-level geologic interpretation to provide context to the data.

Lead Center Researcher: Jarek Trela, Ph.D.
Agency: U.S. Geological Survey
Program: Earth Mapping Resources Initiative
Total Award: $299,999
Project Duration: 3 years (01/23/2023-01/22/2026)

The identification of REE in association with radioactive anomalies and Th led to the exploration for REE in regolith targets, namely on the Cox and Hamp prospects. Hicks Dome Corp. explored regolith in the 1970s and 1980s, Asarco in the 1990s, and GWMG in 2011–2012. Concurrently, fluorspar exploration in the 1970s through the 1990s documented anomalous radioactivity in rock flour matrix breccia which led to the documentation of strongly anomalous amounts of REE (particularly enriched in the heavier elements) along with Y, Nb, and Ti that is associated with the fluorite mineralization. For this phase of the Earth Mapping Resources Initiative project, ISGS characterized regolith zones from across the Illinois fluorspar district and constructed descriptive logs, photographed regolith core, utilized portable x-ray fluorescence, and began preliminary TIMA-X mineral analysis on the Cox and Hamp prospects. REE mineral mass analysis found that the regolith REE concertation was primarily hosted by ferriallanite and florencite. Minor components of REE mineralogy include monazite and columbite. Regolith enrichment at the Cox and Hamp prospects may be analogous to the Mount Weld (W. Australia) laterite deposit. The mineral assemblages of the Cox and Hamp prospects reflect a combination of igneous, metasomatic, and superimposed weathering-biogenic stages, as illustrated by the textural and compositional variety displayed by all REE-minerals. Our preliminary results demonstrate and confirm that the Cox and Hamp regolith prospects at Hicks Dome both contain economically enriched levels of REE that are of great importance for the sustainability of the modern technology market and our nation’s security. Other regolith prospects (overlying either magnetic or radiometric anomalies) will be targeted for exploration.

Lead Center Researcher: M. Jared Thomas
Agency: U.S. Geological Survey
Program: Earth Mapping Resources Initiative
Total Award: $11,524
Project Duration: 2 years (07/01/2024–06/30/2025)

The Earth Mapping Resources Initiative (EMRI) is funding multiple regional projects conducting geochemical reconnaissance of critical minerals distributions across the United States. Hicks Dome (HD) is one such location and represents a rare earth element (REE) enriched volcanic structure straddling the Pope-Hardin County line in southern Illinois that is actively being studied by the Illinois State Geological Survey. The structure has significant critical mineral resources and is considered a layered resource with a REE-enriched regolith (soil) in the near-surface, an underlying HREE-enriched fluorite breccia, and an indication of LREE-enriched carbonatite beneath that. Importantly, HD is concentrically surrounded by fluorite sub-districts, part of the historical Illinois-Kentucky Fluorspar District (IKFD) that once produced over 90% of the nation’s fluorspar. As part of Priority 3 data preservation, ISGS proposes to submit 200 samples from the Hamp Prospect, a highly sampled prospect from the HD regolith.

ISGS preserved 200 REE-enriched regolith samples from the Hicks Dome Cox and Hamp prospects under NGGDDP FY 2024. Samples were submitted to the USGS Geology, Geophysics, and Geochemistry Science Center in Denver, CO for processing, geochemical analysis, and later transfer and archive for posterity. Geochemical data and information obtained during this objective will be in support of the National Index of Borehole Information (NIBI) and US GeoFramework Initiative. Furthermore, ISGS directly contributed to the geospatial compilation of known fluorspar and REE mineral deposits in southern Illinois under Priority 3. ISGS will add the data to an online ArcGIS tool that was developed during an Earth MRI phase II project that delineates subsurface fluorspar districts, magnetic and radiometric anomalies (Phase 1), and igneous-related rare earth element deposit and prospect locations. Newly collected geochemical data on the 200 submitted samples were incorporated and preserved in this database.

Lead Center Researcher: Jarek Trela, Ph.D. and Jared Freiburg, Ph.D.
Agency: U.S. Geological Survey
Program: Earth Mapping Resources Initiative
Total Award: $303,462
Project Duration: 2 years (09/15/2024–09/15/2026)

The identification of mine waste tailings piles associated with historic fluorspar mining in the IKFD is the crucial first step to better constrain fluorite and other critical mineral quantities in southern Illinois. Thus far, no previous study has ever attempted to quantify the volume of mine tailings piles in the area or to estimate the amount of remaining fluorite in those piles. Mapping the locations and size of these piles will provide robust numbers to inform resource estimates supplemented by geochemical analyses.

Fluorspar has many industrial and commercial uses. Some of the most common uses of fluorspar include metallurgical, hydrofluoric acid production, fluorochemicals, cement production, and glass and ceramic production. However, fluorite mining often results in the production of mine waste, including tailings and waste rock, which may contain elevated levels of various constituents, including fluoride, heavy metals (e.g., Zn and Pb), and other contaminants. Tailings are the most common form of mine waste generated during fluorite mining. These are considered waste materials that are left over after the ore is processed to extract the valuable mineral. Tailings, such as those found within the Illinois-Kentucky Fluorspar District, can contain significant amounts of fluoride and potentially critical minerals. ISGS will assess the number of fluorspar mine waste sites located in southern Illinois, quantify the tonnage and grade of fluorspar and potential critical minerals at those sites, and geochemically and mineralogically characterize the material.

Lead Researcher: Patrick I. McLaughlin, Ph.D., Ph.D., and Jared Freiburg, Ph.D.
Project Duration: 7/1/2020–5/1/2024
Funding Agency: U.S. Geological Survey (Earth Mapping Resources Initiative)
Total Award: $150,000

Rare earth element (REE) technologies support an increasing range of high-tech industrial applications that have created a global surge in demand (Long et al., 2010). Heavy REEs (HREE) are of particular importance for their unique properties, which have applications across a spectrum of green technologies from wind turbines, to touch screens, and light-emitting diodes. Current supply imbalances present a national security concern (Van Gosen et al., 2019). A continent-scale assessment identified several unmined phosphorites in the U.S. that are high-grade and larger than the world’s largest conventional HREE deposits (Emsbo et al., 2015, 2017). The highest HREE concentrations recorded in these studies were in Devonian phosphorites. While these values were enriched severalfold above all other phosphorites, the number of analyzed Devonian samples was small. The objective of this project is to conduct a comprehensive regional sampling to verify these extraordinary concentrations, allowing a strategic evaluation of this potential REE resource. This project will provide new science on the concentration and spatial distributions of REEs in Devonian-aged phosphatic sedimentary rocks across the eastern U.S., with the potential to document the largest HREE deposits in the world.

Funding Agency: U.S. Geological Survey (Earth Mapping Resources Initiative)
Total Award: $75,000
Lead Researcher: Patrick I. McLaughlin, Ph.D.
Project Duration: 9/1/2022–8/31/2024

The objectives of this study, in partnership with the Iowa Geological Survey, are to collect new geochemical data on the REE concentrations of Ordovician phosphorites across the Midwest and to map REE concentrations by the age of the phosphorite deposits. This data will also help future evaluation of ore mineralizing system models by documenting geochemical gradients, phosphorite sedimentology, and characteristics of phosphorite-enclosing strata. Ultimately, this is a geochemical reconnaissance project to test if regional concentrations of REEs in Ordovician phosphorites are consistent with the range of values recorded by Emsbo and others (2015) and to gather data on the distribution of the phosphatic host deposits. While the Ordovician stratigraphy of the midwestern U.S. is relatively well studied, there is little data on regional distribution or concentrations of phosphorites. Except for small operations associated with karst deposits in central Tennessee and Kentucky (cf., chemical weathering system), Ordovician phosphorites have not been mined in the U.S. (Chernoff and Orris, 2002). Results of this study will also inform several scientific questions to ultimately facilitate a robust evaluation of the REE resource potential of Ordovician phosphorites.

Lead Researcher: Patrick I. McLaughlin, Ph.D.
Project Duration: 1/10/2023–1/9/2025
Funding Agency: U.S. Geological Survey (Earth Mapping Resources Initiative)
Total Award: $225,000 (Subcontract with Kansas Geological Survey)

The amount of critical minerals (CM) contained in metalliferous black shales can surpass their contents in traditional deposits. While organic-rich black shales have been a proven source of critical minerals like V-Ni-Mo-U-PGE, they represent an underexploited resource. In partnership with the Kansas Geological Survey (KGS), ISGS will coordinate a community-based sampling program across a six-state area (Kansas, Missouri, Iowa, Illinois, Indiana, and Ohio). ISGS will provide guidance and technical support related to geochemical reconnaissance (via portable X-ray fluorescence analysis, pXRF), sample collection (all samples will be sent directly to the USGS for analysis at their contracted lab), interpretation of results, and crafting of the final report.

Lead Researcher: Patrick I. McLaughlin, Ph.D.
Project Duration: 7/1/2023–6/30/2026
Funding Agency: U.S. Geological Survey (Earth Mapping Resources Initiative)
Total Award: $660,000

While currently unmined, Devonian shales in the eastern U.S. contain some of the highest CM concentrations reported in metalliferous shales (Granitto et al., 2017). The Upper Devonian New Albany Shale and equivalent Chattanooga Shale (IL, IA, IN, KY), though currently uneconomic, are considered one of the world’s largest sources of U (Glover, 1959).  Over the course of a 3-year project, the Illinois State Geological Survey and collaborators will provide new science on the concentration and spatial distributions of CMs in Devonian-age black shales across the Illinois Basin.

Lead Researcher: Patrick I. McLaughlin, Ph.D.
Project Duration: 7/1/2024–6/30/2027
Funding Agency: U.S. Geological Survey (Earth Mapping Resources Initiative)
Total Award: $330,000

Earth MRI regional geochemical reconnaissance of Ordovician REE-enriched phosphorites across the central U.S. added significantly to foundational knowledge about the age, distribution, and origin of these little-known critical mineral resources. This project yielded geochemical analysis of over 750 samples from phosphorites and their associated strata across the central U.S. One of the primary findings of this regional reconnaissance project is that a thick REE-enriched phosphatic interval near the base of the Maquoketa Group, in the Dubuque area of northeastern Iowa and adjacent portions of Illinois and Wisconsin, informally known as the “Graf Phosphorite,” is one of the most highly prospective. Results of Earth MRI reconnaissance geochemistry pinpoint the Dubuque area as the regional sweet spot for Upper Ordovician REE-enriched phosphate. In the Dubuque area, the Graf Phosphorite is up to 45 ft thick, divisible into three sub-units, and contains horizons with up to 25% phosphate showing REE enrichment. Whole-rock geochemistry of the purest end member suggests francolite in the Graf Phosphorite averages ΣREE of ~1600 ppm with 800 ppm attributable to ΣHREE. This level of ΣHREE enrichment is considerably higher than currently mined Miocene and Permian phosphate deposits in the U.S. (~500 ppm HREE; Emsbo et al., 2015) but only half the 1600 ppm ΣHREE calculated for the Love Hollow Phosphorite of Arkansas. However, the thickness, geologic setting, and geography of the Graf Phosphorite has shown it to be a more prospective target. The study will specifically address several outstanding questions about the Graf Phosphorite and associated strata in northwestern Illinois.