Browsing by Subject "Geochemical surveys"

Now showing 1 - 3 of 3
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    Exploration Drill Hole Lithology, Geologic Unit, Copper-Nickel Assay, and Location Database for the Keweenawan Duluth Complex, Northeastern Minnesota
    (University of Minnesota Duluth, 2003) Patelke, Richard L
    This report and database compiles virtually all publically available drill hole location data, lithological logging data, copper-nickel assay data, and rock quality data for about 2,145 exploration drill holes in and near the Keweenawan Duluth Complex in northeastern Minnesota. This database covers about 1,779,600 feet of drilling over about 70,000 lithological, and about 70,000 separate assay intervals. All of this drilling is in St. Louis, Lake, and Cook counties. The digital data are presented in an industry standard (Gemcom for Windows) exploration and mine modeling software format, as well as spreadsheet and comma-delimited files for use in other programs. This format can be adapted for use in a GIS program such as ArcView. The purpose of this report is to make these data available to mineral exploration companies in a format almost immediately usable by them.
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    Regional and Local Geologic and Geochemical Controls on Industrial Clay Grades between Granite Falls and Redwood Falls, Minnesota
    (University of Minnesota Duluth, 2004) Heine, John J
    Geologic investigations and industry exploration work prior to this study had focused on the area east of Redwood Falls, MN, where many outcrops of kaolin-bearing materials had been located. This study was initiated to examine the area between Redwood Falls and Granite Falls, MN, in order to determine the potential for large deposits of kaolin-bearing materials. One active kaolin mine and one prospect were located in this area during the study, but most of this area had been largely unexplored.
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    Regional Till Geochemical Survey of the Western Vermilion Greenstone Belt, Minnesota
    (University of Minnesota Duluth, 2004) Larson, Phillip C
    This report presents results of a reconnaissance-scale fine-fraction (silt and clay; -250 mesh, <63μm) till geochemical survey of the western Vermilion Greenstone Belt (VGB). Survey results provide information on the background concentrations of a suite of precious, base metal, and pathfinder elements in till. The survey has identified a number of areas with elevated to anomalous precious and base metal concentrations in till associated with bedrock mineralization in the greenstone belt. The dataset provides a framework for interpretation of the significance of results of future regional and property-scale till geochemical surveys. The survey has identified a number of areas with anomalous precious and base metal concentrations. A prominent zinc anomaly (up to 266 ppm) is present down-ice of Fivemile Lake, underscoring the potential for significant undiscovered zinc mineralization in this area. Highly anomalous copper (314 ppm), gold (54 ppb), molybdenum (26 ppm), and zinc (368 ppm) are present in till in near Needleboy and Armstrong Lakes, suggesting the presence of significant mineralization in an essentially unexplored area. Anomalous gold concentrations suggest significant unidentified gold mineralization exists within the greenstone belt, most notably in the Bass Lake sequence between the Mud Creek shear zone and Vermilion Fault, where gold values up to 940 ppb were identified. Using the results of this survey as a baseline, higher density follow-up till sampling promises to more clearly define and determine the significance of anomalies, as well as determine the location of potential source rocks. Interpretation of mixing of exotic granitic with local greenstone lithologies indicate that over 50% of the fine-fraction material has been transported less than 3 km. Flow direction, transport distance, and probability sector data indicate most geochemical anomalies identified by this survey are correlative with previously identified areas with high potential for bedrock mineralization. This survey demonstrates that till composition in the VGB systematically reflects both bedrock composition and economic mineralization. Results suggest drift exploration methods in general and fine-fraction till geochemical surveys in particular, can be successfully incorporated into an integrated exploration program in the VGB. Higher density sampling is recommended to determine the significance of anomalies and more precisely define source rocks. Further work is recommended to test the applicability till geochemistry to property-scale investigations and of heavy mineral surveys.