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Item Pilot-Scale Demonstration of Increasing Iron Recovery from Minnesota Oxidized Iron Resources(University of Minnesota Duluth, 2018-11-05) Mlinar, Matthew A; Petersen, Tom S; Johnson, Rodney C; Spigarelli, Brett PItem A Bibliography of Published Research in Minnesota Related to the State’s Mineral Potential: June 2023(University of Minnesota Duluth, 2023-06) Hudak, George JThe Minnesota Geological Survey (MGS) was provided funding from the United States Geological Survey (USGS) via the FY 2022 National Geological and Geophysical Data Preservation Program for the “FY22 Minnesota Geological and Geophysical Data Preservation Program.” The program included two priorities that collectively involved 10 separate projects: Priority 1: Data Preservation • Project 1: Preservation of MGS Field Data • Project 2: Seismic Database and Geophysical Compilation • Project 3: Preservation of MGS Cuttings, Phase Three • Project 4: Minnesota Drill Core Library Inventory, Phase Two • Project 5: Data Preservation Workshop Priority 2: Mineral Potential-Related Information • Project 6: State Compilation of Mineral Deposits / Districts • Project 7: Mapping for USGS Compilation of Earth MRI Focus Areas • Projects 8: State Compilation of Borehole Data • Project 9: Prepare For, and Attend, and Follow-Up Earth MRI Workshop • Project 10: Preservation Plan for Critical Minerals As a Component of Priority 2, Project 7, “Mapping for USGS Compilation of Earth MRI Focus Areas,” the Natural Resources Research Institute (NRRI) was subcontracted by the Minnesota Geological Survey (MGS) to prepare a bibliography indicating published geological, geochemical, and geophysical research specific to Minnesota that supports inference of Mineral potential. Matching funding was provided from the NRRI University of Minnesota Permanent University Trust Fund to complete this work. The publications that form the basis of this bibliography are included in NRRI Technical Summary Report “Duluth Complex Geological Bibliography” (Hauck, 2017), “A Bibliography of Published Research in Minnesota Related to the State’s Mineral Potential” (Hudak, 2020), “Minnesota Data Preservation Report for 2019/2020: Updated Data Inventory, Preservation of Pillsbury Hall Rock Collections and Documentation, Assembly of Mineral Potential Related Information” (Thorleifson, 2020), and “A Bibliography of Published Research in Minnesota Related to the State’s Mineral Potential: June 2022” (Hudak, 2022). The following bibliography has been organized utilizing the USGS Mineral Systems approach for critical minerals inventory, research and assessment (Hofstra, 2019; Hofstra and Kreiner, 2020). As Minnesota has a preserved geologic history that spans greater than 3.6 billion years, a wide variety of geological processes encompassing several mineral systems have been active within the State. These include Chemical Weathering, Placer, Meteoric Recharge, Marine Chemocline, Volcanogenic Seafloor, Orogenic, Metamorphic, IOA-IOCG, and Mafic Magmatic. This bibliography includes references specific to each of these mineral systems, as well as a list of references related to potential by-products, recycling, and carbon mineralization publications focused on—and/or referencing—Minnesota resources.Item Phase I fuzzy-logic GIS modeling to evaluate the occurrences of mineral systems in Minnesota(University of Minnesota Duluth, 2022-12) Hudak, George J; Nixon, Kristi; Thakurta, Joyashish; Bartsch, WillEight mineral systems potentially present in Minnesota have been evaluated using fuzzy-logic modeling utilizing ArcMap® software. Data used from the models was derived from the Natural Resources Research Institute Assembling Minnesota dataset. The eight mineral systems modeled include: 1) Placer; 2) Marine Chemocline; 3) Volcanogenic Seafloor; 4) Orogenic; 5) Metamorphic; 6) Alkalic Porphyry; 7) Magmatic REE; and 8) Mafic Magmatic. Inference nets have been developed to illustrate the fuzzy logic and components of each of the mineral system models. Results of the modeling are summarized below by mineral systems: Placer Mineral System: Based on the modeling, the highest probabilities for the presence of a Placer mineral system occur in northeastern Minnesota and in southwestern Minnesota. These regions correlate with the presence of the Biwabik Iron Formation, metasedimentary rocks associated with the Penokean Orogeny, and the margins of the Sioux Quartzite. Marine Chemocline: Based on the modeling, the highest probabilities for the presence of Marine Chemocline mineral systems occur in northeastern and north-central Minnesota in rocks associated with the Animikie Basin and Penokean Orogeny strata. As well, the model indicates high probabilities for the presence of the Marine Chemocline mineral system in western and southwestern Stearns County associated with interlayered volcanic, volcaniclastic, sedimentary, and hypabyssal intrusive rocks that comprise the Mille Lacs Group, North and South Range Groups, and Glen Township Formation. Volcanogenic Seafloor: High potential for the presence of Volcanogenic Seafloor mineral systems were identified in both the Abitibi-Wawa and Wabigoon subprovinces. In the Abitibi-Wawa subprovince, this includes the Vermilion district and the Wilson Lake sequence (Jirsa, 1990). Within the Wabigoon subprovince, enhanced potential for Volcanogenic Seafloor mineral systems occurs in east-central Lake of the Woods County and in northwestern Beltrami County. A single region of high potential for the presence of a Volcanogenic Seafloor mineral system also occurs in north-central Marshall County. Orogenic: The highest probabilities for Orogenic mineral system-associated gold deposits occur within the Abitibi-Wawa and Wabigoon subprovinces within the northernmost one-third of Minnesota. These regions are closely-associated with regional-scale shear zones. The modeled regions correlate well with the six areas of gold exploration identified by Severson (2011), as well as a weights of evidence model developed by Hartley (2014). Metamorphic: Several regions occur where elevated potential for Metamorphic mineral systems exist in Minnesota. The highest modeled potential for such a system exists in east-central St. Louis County and northwestern Lake County; however, this region of modeled high potential may be a false positive due to anomalously high contents of nickel (and perhaps vanadium) within Mesoproterozoic rocks in the area. Other areas with modeled high potential occur within northeastern Koochiching County and are associated with Quetico subprovince high-grade metamorphic rocks in proximity to the Rainy Lake – Seine River Fault, and in northeastern Itaca County, in proximity to the Coon Lake Pluton. Alkalic Porphyry: Modeling conducted for this study indicates several regions where elevated potential for Alkalic Porphyry mineral systems exist. The areas with the highest modeled probability for having Alkalic Porphyry mineral systems occur in northeastern Minnesota with Lake, St. Louis, and Itasca counties. Magmatic REE: Regions with the highest modeled potential for Magmatic REE mineral systems occur in south-central Lake County, north-central and northwestern St. Louis County, northeastern Itasca County, east-central Koochiching County, southeastern Marshall County, and east-central Stearns County. These are associated with Neoarchean syenite, monzodiorite, granodiorite, and diorite and granite-rich migmatites, Neoarchean gabbro, peridotite, pyroxenite, lamprophyre and metamorphic equivalents, and Paleoproterozoic porphyritic granites. Mafic Magmatic: Fuzzy-logic modeling indicates the highest probability for the presence of Mafic Magmatic mineral systems occurs in northeastern Lake County, east-central St. Louis County, and within eastern Aitkin County. The model identified known disseminated-to-massive Cu-Ni-PGM deposits that occur in troctolitic rocks at the base of the Duluth Complex in Lake and St. Louis counties, as well as Ti-Voxide deposits and prospects associated with oxide ultramafic intrusions (peridotites, pyroxenites) that occur along the western margin of the Duluth Complex in central St. Louis County. As well, the model identified the location of the Tamarack intrusion in eastern Itasca County, the host of the Tamarack Ni- Cu-Co deposit.Item A Bibliography of Published Research in Minnesota Related to the State’s Mineral Potential: June 2022(University of Minnesota Duluth, 2022-06) Hudak, George JThe Minnesota Geological Survey (MGS) was provided funding from the United States Geological Survey (USGS) via the FY 2021 National Geological and Geophysical Data Preservation Program for the “FY21 Minnesota Geological and Geophysical Data Preservation Program.” The program included two priorities that collectively involved 11 separate Projects: Priority 1: Data Preservation • Project 1: Preservation of MGS Field Data • Project 2: Preservation of MGS Cuttings • Project 3: Minnesota Drill Core Library Inventory, Phase I • Project 4: Data Preservation Workshop Priority 2: Mineral Potential-Related Information • Project 5: State Compilation of Mineral Deposits / Districts • Project 6: Contribute Data to USGS Map Compilation of Focus Areas • Projects 7 and 8: State Compilation of Borehole Data with Metadata to NDC • Project 9: Update Geologic Map Database • Project 10: USGS Critical Minerals Workshop • Project 11: Strategic Plan for Critical Minerals As a Component of Priority 2, Project 6, “Contribute Data to USGS Map Compilation of Focus Areas,” the Natural Resources Research Institute (NRRI) was subcontracted by the Minnesota Geological Survey (MGS) to prepare a bibliography indicating published geological, geochemical, and geophysical research specific to Minnesota that supports inference of Mineral potential. Matching funding was provided from the NRRI University of Minnesota Permanent University Trust Fund to complete this work. The publications that form the basis of this bibliography are in NRRI Technical Summary Report “Duluth Complex Geological Bibliography” (Hauck, 2017), “A Bibliography of Published Research in Minnesota Related to the State’s Mineral Potential” (Hudak, 2020), and “Minnesota Data Preservation Report for 2019/2020: Updated Data Inventory, Preservation of Pillsbury Hall Rock Collections and Documentation, Assembly of Mineral Potential Related Information (Thorleifson, 2020). Matching funding was provided from the NRRI University of Minnesota Permanent University Trust Fund to complete this work. The following bibliography has been organized utilizing the USGS Mineral Systems approach for critical minerals inventory, research and assessment (Hofstra, 2019; Hofstra and Kreiner, 2020). As Minnesota has a preserved Geologic history that spans greater than 3.6 billion years, a wide variety of geological Processes encompassing a number of Mineral Systems have been active within the State. These include Chemical Weathering, Placer, Meteoric Recharge, Marine Chemocline, Volcanogenic Seafloor, Orogenic, Metamorphic, IOA-IOCG, and Mafic Magmatic. This bibliography includes references specific to each of these Mineral Systems, as well as a list of references Related to potential by-products, recycling, and carbon Mineralization publications focused on Minnesota resources.Item Western Mesabi Iron Resources of the Future(University of Minnesota Duluth, 2022-09-15) Johnson, Rodney C; Mlinar, Matthew A; Spigarelli, Brett P; Post, Sara PThe purpose of this study was to initiate a long-term comprehensive characterization program of the remaining iron resources of the Mesabi Iron Range to provide a foundation for the future iron industry in Minnesota. This data is being used to direct research in the areas of reducing reliance on fossil fuels, reducing emissions, and to identify and develop value-added iron products that could be produced from underutilized portions of Minnesota iron resources. Two complete sections of the iron formation were analyzed in this study. The results have contributed to a better understanding of the mineralogical variability within the iron formation; the impacts of oxidation on iron product quality; the potential for new iron-based products; and the presence of trace elements.Item Opportunities Offered by Emerging Hydrometallurgical Technologies(University of Minnesota Duluth, 2022-08) Rao, Shashi; Mlinar, Matthew A; Hudak, George J; Kangas, Kevin W; Peterson, Dean MMinnesota has abundant mineral resources, including deposits of iron, iron manganese, copper-nickel- cobalt-platinum group elements, titanium-vanadium, copper-zinc, gold with and without silver, sand, and aggregate. Commercial and industrial byproducts such as mine tailings, industrial residues, and waste electrical and electronic equipment also contain valuable mineral resources. To address significant environmental impact concerns associated with mining, collection and processing of these materials, new processing technology approaches with reduced water and energy consumption and minimal environmental footprints are needed to support production of value-added products. Emerging hydrometallurgical processing technologies offer promising opportunities. Hydrometallurgy techniques have a range of applications from extraction of high-value products from mineral and recycled materials to water remediation to generating secondary products for carbon sequestration. To evaluate the technical, economic, and environmental resiliency of emerging hydrometallurgical innovations, the Minnesota Legislative-Citizen’s Commission on Minnesota Resources (LCCMR) provided funding to the Natural Resources Research Institute (NRRI) to evaluate how to best support the development of emerging hydrometallurgical technologies in the state. To support this effort, NRRI evaluated: 1) A summary of perceived current and future hydrometallurgical needs of stakeholders based on a “voice of customer” (VOC) survey. 2) A discussion of how to apply hydrometallurgical capabilities to Minnesota-specific mineral and waste resources to maximize long-term economic, environmental, and social benefits and resilience. 3) A vision developed to advance Minnesota’s research capabilities in mineral characterization, mineral processing, extraction, and refining via hydrometallurgy that will lead to more efficient and effective utilization of Minnesota minerals and waste resources in the future. This research digs deeper into emerging applications of hydrometallurgical techniques in the production of value-added materials from a range of primary and secondary resources. The report also explores how application of these techniques to regional resources could potentially foster a more diversified minerals economy in Minnesota, develop treatment technologies to protect water resources, utilize regional resources for carbon mineralization, and supply materials required to build clean energy technologies.Item Research, Development, and Marketing of Minnesota’s Iron Range Aggregate Materials for Midwest and National Transportation Applications: Final Compendium Report to the Economic Development Administration(University of Minnesota Duluth, 2010-11) Zanko, Lawrence M; Fosnacht, Donald R; Hauck, Steven AFrom January 1, 2006 to June 30, 2010, a comprehensive taconite aggregate research and demonstration program was undertaken. The program’s main objectives were to: • identify new and economically viable uses for Minnesota Iron Range taconite aggregate material in road construction and repair projects; and • conduct demonstration projects inside and outside Minnesota, including targeted Upper Midwest States. To assure program success, a cooperative and collaborative research approach was taken using expertise from both public and private entities. The program proceeded in two major phases. The first phase aimed at assessing the resource and road construction market opportunity in terms of technical information on aggregate applications, unique properties and benefits, different mix designs and attributes, alternative products and technologies, and to build awareness and interest in the expanded use of taconite aggregate products at the regional and national scale. Material logistics and costs, and market opportunities and approaches to demonstrate taconite aggregate’s advantages were also assessed during this first phase. The second phase expanded on the first phase findings and used them as a guide for demonstrating the actual use of taconite aggregate products on a larger scale throughout Minnesota and the Midwest in potential construction applications. The geologic characteristics of potential aggregate materials on Minnesota’s Mesabi Iron Range were characterized on a broad basis during both phases.Item Shaded Relief Map of the Basal Contact Surface of the South Kawishiwi Intrusion Duluth Complex, Northeastern Minnesota(University of Minnesota Duluth, 2002-03) Peterson, Dean MThis map depicts a 3-dimensional model of the interpreted shape of the bottom of the western margin of the South Kawishiwi Intrusion (SKI) that is based on ~800 drill hole piercing points into footwall rocks and geophysical data (gravity and aeromagnetic). Severson (1994) defined the igneous stratigraphy of the SKI in the map area based on drill core logging, and the vast majority of all geological information used by the author in the development of this map is taken from that work. Compilation and modeling of geochemical data for all of the mineralized zones within the Partridge River and South Kawishiwi intrusions has been presented by Peterson (1997), and is the source for much of the drill hole assay data within the map area. New interpretations and descriptions of the geology and mineral potential of the whole Duluth Complex have been recently completed (Miller et al., 2001; 2002), and readers interested in the geology of this map area should refer to all these works. A simplified 3-dimensional bedrock geological map of the rocks adjacent to, within, and beneath the western margin of the South Kawishiwi Intrusion is presented in Figure 1. Cross sections of the topographic expression of the basal contact of the SKI are presented in Figure 2. The 3-D model has been instrumental in the development of new ideas on the styles and origin of the Cu- Ni-PGE mineralization within the SKI. Integration of regional geological, geophysical, and geochemical features with the 3-D model has led to new ideas on possible feeder channels for magmas of the northern SKI. The interpreted master magmatic feeder channel of the northern SKI is fed from the central Mid- Continent Rift through the Bald Eagle Intrusion gravity high, into a dike-like body of troctolitic rocks (herein termed the Bald Eagle Trough) cutting older Anorthositic Series rocks (Fig. 3). Integration of the concept of a magmatic feeder channel with assays has led to the development of conceptual models for the formation of the Spruce Road (Peterson, 2002) and Maturi (Peterson, 2001) deposit areas. Early magmas that formed the Spruce Road deposit were deflected to the north by a pillar of older Anorthositic Series rocks that is located at depth within the northern portion of the SKI (Fig. 1). Moreover, PGE-enriched Cu-Ni mineralization of the Maturi Extension deposit is located beneath the pillar, and a conceptual model for the formation of this deposit area is presented in Peterson (2001). 1) Open - (early) vertically extensive (> 450 meters) mineralization with generally low to moderate Cu-Ni grade and low Au+PGE grades; and 2) Confined - (later) vertically restricted (< 150 meters) mineralization with moderate to high Cu-Ni grades and moderate to very high (locally) Au+PGE grades; and 3) Cloud Zone - (latest) Cu-Ni-PGE mineralization seemingly unrelated to the basal contact. Regional geologic and crosscutting relationships (Fig. 3) indicate that the Open-style mineralization preceded the Confined-style.Item Bedrock Geology, Sample Location, and Property Position Maps of the West Birch Lake Area, South Kawishiwi Intrusion, Duluth Complex, Lake and St. Louis Counties, Northeastern Minnesota(University of Minnesota Duluth, 2002-04) Peterson, Dean M; Marma, John; Brown, PhilipThis map (NRRI/MAP-2002/02) is the outcome of eight field days mapping and sampling in the area by the senior author. The initial impetus for this mapping was to try to define Duluth Complex induced contact-metamorphic zonation in the footwall Giants Range batholith, and to relate this to Cu-rich mineralization in these rocks. Research into footwall Cu-rich mineralization continues, and will be published in the future. However, the discovery of large expanses of Cu-Ni mineralized rock in the basal zone of the South Kawishiwi, in an essentially unmapped area, lead to this preliminary map (Figure 1). The geologic map represents the initial interpretaton of the bedrock geology of the basal zone of the South Kawishiwi Intrusion, based on mapped outcrops, subcrops, and glacial materials (float). In addition, geologic units intersected in drill holes have been projected updip to the surface. The faults depicted on the map are interpreted from aeromagnetic data, steepening of the dip of the basal contact of the Duluth Complex, and topographic lineaments. The location and simplified regional geology encompassing the map area is depicted in Figure 4. The lithologic legend of the geology map is simplified into the intrusive stratigraphy of the South Kawishiwi Intrusion first defined by Severson (1994). Readers interested in detailed descriptions of the regional South Kawishiwi Intrusion stratigraphy are referred to that work. Cu-Ni-PGE mineralization is largely confined to the basal stratigraphic units of the intrusion (units BAN, BH, and U3), and on the ground is largely represented by knob-like outcrops, and large expanses of rusty, gossaneous boulder fields (subcrops). Old test pit dumps (circa 1890 ?) into the Biwabik Iron Formation are common in the southern portion of the map, and occur in areas of anomalous magnetic field properties. Seventy-five rock samples (Figure 2) were collected in the area (described in Table 1), and Dr. Philip Brown and John Marma (Department of Geology, University of Wisconsin - Madison) provided the funding for the base- and precious-metal analyses of twenty of these samples (presented in Table 2). Check assays for anomalous samples were analyzed by ALS Chemex labs from the original pulps and rejects (Table 2). Assay data for the majority of the drill holes in the map area have been compiled by Peterson (1997), which includes > 60,000 geochemical analyses for drill holes throughout the Duluth Complex. The smaller-scale property position map (Figure 3) depicts the current mineral lease holders in the area, and should only be viewed as a "snapshot" of the mineral land positions at the date of this map. Detailed geologic mapping in the area, including additional geochemical analyses, has been approved from the Permanent University Trust Fund, and will be completed during the 2002 field season.Item Bedrock Geology Map of the Nickel Lake Macrodike and Adjacent Areas: Lake County, Northeastern Minnesota(University of Minnesota Duluth, 2006-11) Peterson, Dean M; Albers, Paul B; White, Chris RThis map is the first of what is hoped (contingent on funding) to be a series of new detailed bedrock geology maps of the marginal zone of the South Kawishiwi Intrusion by the University of Minnesota Duluth's Natural Resources Research Institute (see Peterson, 2006). Such mapping will form the basis for continued exploration for Cu-Ni-PGE mineralization as well create the geologic base upon which environmental review associated with exploitation of such mineralization can be built. Recent detailed mapping at a scale of 1:5,000 by the authors was conducted west and south of the Boundary Waters Canoe Area Wilderness (BWCAW). Nearly 1,000 outcrops along approximately 100 kilometers of field traverses were examined to identify and confirm the internal lithologic variability, contact relationships, and structure of the Nickel Lake Macrodike between the BWCAW and Omaday Lake. The authors wish to acknowledge Dr. Paul Weiblen (emeritus professor of geology at the University of Minnesota) for his keen insight of the geology of the area and Dr. George Hudak and undergraduate student Jeremiah Gowey of the University of Wisconsin Oshkosh for assistance in mapping outcrops around and south of Omaday Lake. Additional reconnaissance mapping in early November by the senior author was conducted to field check compiled outcrop locations depicted on the 1957 INCO map of the Spruce Road Deposit and the 1968 Hanna Mining map of the South Filson Creek Deposit (both of which are publically available in the DNR archive at Hibbing, Minnesota). The reconnaissance mapping confirmed the location of gossaneous Cu-Ni bearing INCO outcrops and reconfirmed the outstanding field mapping of all types of Duluth Complex rocks by Hanna Mining Company geologists of the late 1960s (see figure of "Sources of Information"). This map has been built upon (in the areas surrounding depicted outcrops and historic drill holes) the 1966 map of the Gabbro Lake 15' quadrangle by Green et al. (Minnesota Geological Survey Miscellaneous Map M-2), which because of its quality has been the geologic foundation for this area for 40 years. The reader of this map should compare the author's interpretation of the bedrock geology to that depicted on M-2, which will undoubtedly highlight the need for continued detailed mapping of the marginal zone of the South Kawishiwi Intrusion (which was not the purpose of map M-2), especially in light of the greatly increased interest in the potential for exploiting the vast resources of Cu-Ni-PGE mineralization enclosed within these rocks. The Nickel Lake Macrodike is lithologically and structurally related to the South Kawishiwi Intrusion and the known Cu-Ni-PGE deposits of Birch Lake, Maturi, Maturi Extension, Spruce Road, and South Filson Creek. The citation for this map includes the caveat "Version 1", which points out the fact that the authors believe that more detailed geologic mapping and analytical studies (no petrography or geochemical analyses of recently collected samples has been completed) are needed to truly understand what the bedrock geology enclosed within the boundaries of this map sheet (and the area to the west-southwest) really is (ie. we've only begun to scratch the surface). This map and all associated GIS data (in ArcView 3.2 format) can be obtained online at http://www.nrri.umn.edu/egg/publicationlist.html.Item Digital Base for Geological Mapping within the Northern South Kawishiwi Intrusion: Lake and St. Louis Counties, Northeastern Minnesota(University of Minnesota Duluth, 2006-07) Peterson, Dean MThis map depicts the outcome of several hundred hours of digitizing contour lines and associated topographic map data (lakes, streams, roads, trails) as well as updating a three-dimensional database of drill hole information and scattered surface sample geochemical analyses for the northern portion of the South Kawishiwi Intrusion. The data was digitized in three-dimensions, and was used to generate the 3D image of the surface topography that forms the background of the map sheet. As well, all of the data has been incorporated into a detailed GIS basemap of the area. The purpose of this work is two-fold: (1) to visually comprehend the geomorphology of this area (which is in the scoured bedrock terrane of northeastern Minnesota) as a tool in understanding the bedrock and surficial geology, and (2) to provide a visual impetus for funding a large geological mapping project in this economically significant (Cu-Ni-PGE mineral potential) and environmentally sensitive (BWCAW) area. Such a project would need financial support from both the University of Minnesota Duluth's Natural Resources Research Institute and from companies in the Minerals Industry that have active Cu-Ni-PGE mineral exploration programs situated within the boundaries of this map sheet (Duluth Metals Limited, Franconia Minerals, Encampment Resources). These active mineral exploration activities are being driven by greatly increased metal prices as a result of global economic expansion. Previous mineral exploration programs within the boundaries of this map sheet has included approximately 607 exploration holes totaling over 90 miles of core (296 kilometers) that was drilled between the years 1951 - 2006. Integration of geologic data from these historic exploration programs into a conservative geological resource estimate of contained copper, nickel, platinum, palladium, and gold indicates that at today's metal prices, over $500 billion dollars of these metals (which includes an estimated 50 million ounces of palladium, 25 million ounces of platinum, and 10 million ounces of gold) is hosted by the South Kawishiwi Intrusion within this map sheet (Peterson, unpublished data). The economic significance of these geological resources, along with the possible extraction of these metals in the future, is driving the author's desire to complete a new geological map of a large portion of this area. Published geological maps of portions of this sheet are given in the "INDEX TO MAPPING". Review of this figure highlights the need for a new mapping campaign, namely that the bulk of this area has only been mapped at small scales (1:31,680 and 1:48,000 scales) thirty to forty years ago, prior to the great advances in our knowledge of the geology, geophysical characteristics (Fig. 1), and mineralization in the Duluth Complex over the past twenty years.Item Bedrock Geologic Map of the Duluth Complex in the Northern South Kawishiwi Intrusion and Surrounding Area, Lake and St. Louis Counties, Minnesota(University of Minnesota Duluth, 2008-05) Peterson, Dean MThis map is the result of numerous investigations by the author and many others over the last 8 years of the South Kawishiwi intrusion (SKI) and it's contained Cu-Ni-PGE mineralization. Detailed geological mapping evolved from a study of the Nickel Lake Macrodike (NLM) into a comprehensive geologic mapping and compilation project (104,000 acres) to answer some of the fundamental questions on the origin of the extensive known and undiscovered Cu-Ni-PGE mineralization in the northern portion of the SKI. Such an increase in scope is needed due to the economic significance of the published resource estimates (>$146 billion in contained metal) from this area. To date, nearly 15,000 outcrops, 1,400 structural measurements, geology and geochemistry from 773 drill holes totaling over 845,000 feet of core, and 12,500,000 meters of elevated contour lines (see Digital Topography image below) have been integrated into the comprehensive GIS database. The map units of the SKI depicted on this map sheet differ from previous maps from the area, in that the author has consulted with numerous company geologists and defined map units based on what industry geologists use to define rock masses encountered in drill core. This new map includes geology from each of the major lithologic units in the area, namely the Late Archean Giants Range batholith, the Paleoproterozoic Biwabik Iron and Virginia Formations, and the Anorthositic Series, Bald Eagle Intrusion, SKI, and the NLM of the Mesoproterozoic Duluth Complex. There are only a few faults depicted on the map, and literally hundreds of kilometers of linear topographic features that remain to be investigated in detail (see Digital Topography image below). However, little obvious offset of rock units have been observed along these features where investigated in detail, thus the author has purposely not drawn many faults on the map. One main new insight of this recently completed compilation is the recognition that the northeastern extent of the SKI is not a shallowly dipping sill but rather a southwest trending, inclined funnel-like body. Such an interpretation leads to the conclusion that the eastern contact of the SKI, which previously was interpreted as the top of the intrusion, is a basal contact, and thus has great potential for hosting Cu-Ni-PGE mineralization at its base. Understanding the origin of mineralized zones is the goal of all economic geologists, and in magmatic ore systems like the SKI, one must try to imagine the magmatic processes that culminated in the formation of the ores and surrounding rocks, i.e. how did the SKI form? Did the magmas intrude as crystal-laden slurries? Are the "Open" and "Confined" styles of mineralization defined by Peterson (2001) true mappable units? Such thoughts are the basis upon which the author began the quest to complete this map sheet. The author has inserted a number of inset maps and figures for the reader to review and ponder about the possible types of magmatic prosesses that occurred in the area (now depicted on this map sheet) 1.1 billion years ago. It is hoped that careful review of the bedrock geologic map and inset figures will give the reader and user of the map new geologic insight and ideas for future mineral exploration programs and scientific study.Item Mesabi Hard Rock Usage in Minnesota(University of Minnesota Duluth, 2006) Patelke, Marsha MeindersExample projects represent a subset of Mesabi Hard Rock usage statewide.Item Bench-Scale Evaluation of Hydrometallurgical Processing to Recover Vanadium from Minnesota Titanium Resources(University of Minnesota Duluth, 2021-10) Hudak, George J; Monson Geerts, Stephen D; Chen, Jonathan; Halim, A; Sridhar, Ram; Lakshmanan, V.I.Vanadium is the twenty-second most abundant element in the Earth’s crust and occurs as a major component (greater than 10% by weight) in 156 minerals that occur in a variety of mineral deposit types. These mineral deposit types are globally distributed and include vanidiferous titanomagnetite (VTM) deposits, sandstone hosted (SSV) deposits, shale-hosted vanadium deposits, and vanadate deposits (Kelley et al., 2017). The Duluth Complex of northeastern Minnesota contains a variety of base and precious metal resources (Fig. 1), including a number of Mesoproterozoic-age copper-nickel-cobalt-platinum group element (Cu-Ni-Co-PGE) resources as well as a series of younger, Mesoproterozoic-age oxide ultramafic intrusions (OUIs) that contain both titanium and vanadium resources (Minnesota Minerals Coordinating Committee, 2016; Table 1). Vanadium deposits within OUI deposits associated with the Duluth Complex are classified as vanadiferous titanomagnetite (VTM-type) vanadium deposits by the United States Geological Survey (USGS; Kelley et al., 2017). World resources of vanadium are greater than 63 million tons; however, vanadium concentrations generally constitute less than 2% of the deposit host rock (Polyak, 2021). In 2020, mine production of vanadium worldwide was approximately 94,800 tons, with the United States (0.2%), Brazil (7.7%), China (61.6%), Russia (21.0%) and South Africa (9.5%) being the major producers (Polyak, 2021). Vanadium is utilized in a variety of applications. Its principal use is for the production of metal alloys such as high-strength steel and alloys utilized in the aerospace industry. It is also used for catalysts in the chemical industry, in ceramics, in glasses, and as a pigment (Schulz et al., 2017). Production of carbon-, full-alloy-, and high-strength low-alloy steels accounted for 18%, 45%, and 33% of domestic consumption in 2020, respectively (Polyak, 2021). The emerging need for large-scale “green” electrical energy storage associated with wind, solar, and other intermittent power sources may result in major utilization of vanadium in the form of vanadium redox-flow batteries (VFRB) which take advantage of the various electrical valencies of vanadium cations (https://energystorage.org/why-energy-storage/technologies/vanadium-redox-vrb-flow-batteries/). As well, vanadium is utilized in other battery applications, including lithium-vanadium-phosphate batteries and lithium ion batteries (Schulz et al., 2017). Commercial products resulting from processing of vanadium ores include ferrovanadium (FeV, an iron-vanadium alloy), which is used in the production of steel alloys, vanadium pentoxide (V2O5), which is commonly utilized as a chemical catalyst, and ammonium metavanadate (NH4VO3), a precursor for the production of vanadium pentoxide, catalysts, and analytical reagents (Pérez-Benítez and Bernès, 2018). In 2020, U.S. net import reliance for vanadium was 96%, with major import sources being Brazil, South Africa, Austria and Canada (United States Geological Survey, 2021). A large portion of domestic needs could be met by domestic resources and secondary recovery processes (Polyak, 2021). As a result of this large net import reliance, vanadium is considered a critical mineral resource in the United States (Executive Order 13817 “Federal Strategy to Ensure Reliable Supplies of Critical Metals”; Schulz et al., 2017; Nassar and Fortier, 2021). Results of recent hydrometallurgical experiments conducted by Process Research Ortech (PRO) and the Natural Resources Research Institute (NRRI) indicate that vanadium concentrations continue to increase within titanium raffinate as recycling of organics takes place in a closed-system hydrometallurgical circuit developed to produce TiO2 and Fe2O3 products from the Longnose OUI mineral deposit (Hudak et al., 2021). The research described in this report discusses collaborative research conducted by PRO and NRRI to evaluate whether or not high-purity vanadium materials (specifically ammonium metavanadate and vanadium pentoxide) could be produced as by-products of hydrometallurgical processing of the titanium raffinate solutions resulting from continuous pilot-scale hydrometallurgical processing of Longnose mineral concentrates (Hudak et al., 2021).Item Continuous Pilot-Scale Demonstration of Ilmenite Processing Technology(University of Minnesota Duluth, 2021-05) Hudak, George J; Rao, Shashi; Peterson, Dean M; Chen, Jonathan; Lakshmanan, V.I.; Sridhar, Ram; Gluck, EugenItem A Bibliography of Published Research in Minnesota Related to the State’s Mineral Potential: April 2020(University of Minnesota Duluth, 2020-04) Hudak, George JThe United States Geological Survey (USGS) provided funding via the FY 2019 National Geological and Geophysical Data Preservation Program (NGGDPP) for the project “Updated Minnesota Data Inventory: Preservation of Pillsbury Hall Rock Collections with Associated Additional Documentation: Assembly of Mineral Potential Related Information.” The three priority components of this project were as follows: • Priority 1: Collection Inventory and metadata record revision in the National Digital Catalog; • Priority 2: Preservation of Pillsbury Hall Rock collections with associated and additional documentation; and • Priority 3: Assemble information that supports identification of critical mineral resources in Minnesota. As part of Priority 3, the Natural Resources Research Institute (NRRI) was subcontracted by the Minnesota Geological Survey to prepare a bibliography briefly describing published research specific to Minnesota that supports inference of mineral potential on the basis of geological mapping, and a bibliography listing references for published literature on this topic. The NRRI provided matching funding to complete this work from the NRRI University of Minnesota Permanent University Trust Fund. The USGS has recently developed a new minerals system approach for critical minerals inventory, research and assessment (https://www.usgs.gov/energy-and-minerals/mineral-resourcesprogram/ science/systems-approach-critical-minerals-inventory?qt-science_center_objects=0#qtscience_ center_objects; Hostra, 2019). The following bibliography is organized utilizing this minerals system classification scheme. As Minnesota has a preserved geologic history that spans greater than 3.6 billion years, and as a wide variety of geological processes have been active over this geological history, mineral potential exists in many of the mineral systems, including Chemical Weathering, Placer, Meteoric Recharge, Marine Chemocline, Volcanogenic Seafloor, Orogenic, Metamorphic, IOA-IOCG, and Mafic Magmatic. As well, a short bibliography of potential By-Products/Recycling resources has been included with this bibliography.Item Summary Report: Environmental Particulate Matter Characterization(University of Minnesota Duluth, 2019-11) Monson Geerts, Stephen D; Hudak, George J; Zanko, Lawrence M; Fosnacht, Donald RThe NRRI characterization studies provide physical (size and shape), mineralogical, chemical, geological, geographical, and historical context to the findings of the University of Minnesota’s School of Public Health (SPH) and the University of Minnesota Medical School (UMMS). The SPH and UMMS findings (Finnegan and Mandel, 2014) showed that mesothelioma is associated with working longer in the taconite industry. However, the SPH and UMMS investigators “…were not able to state with certainty that the association with EMPs and mesothelioma was related to the ore dust or to the use of commercial asbestos or both.” The NRRI findings indicate the following: 1) Low concentrations of PM10, PM2.5, and EMPs in Mesabi Iron Range community air. 2) Elemental iron concentrations in MIR communities were similar to elemental iron concentrations in background sampling locations when taconite mines/plants were inactive. When taconite mines/plants were active, the elemental iron concentrations within communities were found to be statistically higher. 3) Mineralogically and morphologically, the EMPs identified in MIR communities and taconite processing plants were dominated by particles that did not fit the “countable”/”covered” classification criteria. Of the 145 “covered” EMPs identified within the six MIR taconite processing plants, a total of 8 were “countable” (NIOSH, 2011), representing 1.1% of the total number of EMPs, out of 691 total. These EMPs were detected in two taconite plants (seven in one plant and one in another); no other “countable”/”covered” EMPs were detected in the other four plants. 4) The lake sediment study returned similar results, in which 4 of the study’s 790 identified EMPs found in the lake sediment samples met the “countable”/”covered” classification. 5) In comparison to the NIOSH standard, for countable particles, the results from this study show that the community air has significantly lower amounts than the standard. 6) Only one plant and two areas in this plant had countable EMPs above the NIOSH benchmark. 7) The highest particulate matter found was for the Minneapolis reference site in comparison for the Range communities and the other two reference sites. 8) The use of MOUDI sampling techniques is a good method for better understanding not only what is in the air, but also the size of the particles that are in the air. 9) Study of lake sediment can be used to interpret some of the impacts of past industrial activities and to gain a better understanding of the impact of local geology.Item Minnesota Taconite Workers Health Study: Environmental Study of Airborne Particulate Matter in Mesabi Iron Range Communities and Taconite Processing Plants - Lake Sediment Study(University of Minnesota Duluth, 2019-12) Zanko, Lawrence M; Reavie, Euan D; Post, Sara PAtmospheric deposition of airborne particulate matter such as fugitive dust contributes to sediment that accumulates at the bottom of a lake. Because of this phenomenon, lake sediment can provide an historic mineralogical and chemical record of what may have been in the air at the time of its atmospheric deposition. This point is important, because the NRRI’s role in the Minnesota Taconite Workers Health Study (MTWHS) was to not only help answer the question “What is in the air?” by conducting present-day in-plant and community air sampling, but – and even more challengingly – to potentially answer the question “What was in the air, when?” by collecting and analyzing historic samples. Lake sediment was the only historic sampling medium available that could allow the investigators to make an attempt to assess what might have been present in the air in the past on Minnesota’s Mesabi Iron Range (MIR). The NRRI therefore core-sampled, age-dated, and characterized intervals of sediment from two MIR lakes – Silver Lake in Virginia, on the central MIR, and “North-of-Snort” Lake on the eastern end of the MIR, near Babbitt (Fig. i). The objective was to determine if fugitive mineral dust generated by past iron ore/taconite mining activity could be discerned in mineral particulate matter (PM) deposited and preserved in the sediment of both lakes.Item Minnesota Taconite Workers Health Study: Environmental Study of Airborne Particulate Matter in Mesabi Iron Range Communities and Taconite Processing Plants - Elemental Chemistry of Particulate Matter(University of Minnesota Duluth, 2019-12) Monson Geerts, Stephen D; Hudak, George J; Marple, Virgil; Lundgren, Dale; Gordee, Sarah M; Olson, Bernard; Zanko, Lawrence MThe Minnesota Taconite Workers Health Study (MTWHS) was initiated in 2008 and included a multicomponent study to further understand taconite worker health issues on the Mesabi Iron Range (MIR) in northeastern Minnesota. Approximately $4.9 million funding was provided by the Minnesota Legislature to conduct five separate studies related to this initiative, including: ▪ An Occupational Exposure Assessment, conducted by the University of Minnesota School of Public Health (SPH); ▪ A Mortality (Cause of Death) study, conducted by the University of Minnesota SPH; ▪ Incidence studies, conducted by the University of Minnesota SPH; ▪ A Respiratory Survey of Taconite Workers and Spouses, conducted by the University of Minnesota SPH; and ▪ An Environmental Study of Airborne Particulate Matter, conducted by the Natural Resources Research Institute (NRRI) at the University of Minnesota Duluth (UMD). NRRI’s “Environmental Study of Airborne Particulate Matter” comprises a multi-faceted characterization of size-fractionated airborne particulate matter (PM) from MIR community “rooftop” locations, background sites, and all taconite processing facilities active between 2008 and 2014. Characterization includes gravimetric determinations, chemical characterization, mineralogical characterization, and morphological characterization. This report specifically discusses the elemental chemistry of particulate matter (PM) collected from the rooftops of five communities located within the Mesabi Iron Range (MIR), three reference or background locations, and the six taconite processing plants while they were active (operating) and inactive (temporarily, but completely, shut down). The samples were collected between 2008 and 2011.Item Minnesota Taconite Workers Health Study: Environmental Study of Airborne Particulate Matter in Mesabi Iron Range Communities and Taconite Processing Plants - A Characterization of the Mineral Component of Particulate Matter(University of Minnesota Duluth, 2019-12) Monson Geerts, Stephen D; Hudak, George J; Marple, Virgil; Lundgren, Dale; Zanko, Lawrence M; Olson, Bernard; Bandli, BryanThe Minnesota Taconite Workers Health Study (MTWHS) was initiated in 2008 and included a multicomponent study to further understand taconite worker health issues on the Mesabi Iron Range (MIR) in northeastern Minnesota. Approximately $4.9 million funding was provided by the Minnesota Legislature to conduct five separate studies related to this initiative, including: An Occupational Exposure Assessment, conducted by the University of Minnesota School of Public Health (SPH); A Mortality (Cause of Death) study, conducted by the University of Minnesota SPH; Incidence studies, conducted by the University of Minnesota SPH; A Respiratory Survey of Taconite Workers and Spouses, conducted by the University of Minnesota SPH; and An Environmental Study of Airborne Particulate Matter, conducted by the Natural Resources Research Institute (NRRI) at the University of Minnesota Duluth (UMD). Results of the four studies conducted by the University of Minnesota SPH can be found on the Taconite Workers Health Study website (http://taconiteworkers.umn.edu/news/documents/Taconite_FinalReport_120114.pdf). NRRI’s “Environmental Study of Airborne Particulate Matter” comprises a multi-faceted characterization of size-fractionated airborne particulate matter (PM) from MIR community “rooftop” locations, background sites, and all taconite processing facilities active between 2008 and 2014. Characterization includes gravimetric determinations, chemical characterization, mineralogical characterization, and morphological characterization. This report specifically discusses the mineralogy and morphology of EMPs collected from the rooftops of five communities located within the MIR, three reference or background locations, and the six taconite processing plants. The samples were collected between 2008 and 2011.