Browsing by Subject "Copper-nickel"

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    Airborne Imaging Scanner Survey of Northeastern Minnesota
    (University of Minnesota Duluth, 1990-04) Hauck, Steven A; Ager, Cathy; Pastor, John; Zanko, Lawrence M; Aaseng, N
    An airborne imaging scanner survey was flown over two areas in the Duluth Complex and one area along the Vermilion fault zone on September 12, 1988 to detect heavy metal induced stress in plants due to the presence of buried mineral deposits. The Duluth Complex flight lines covered copper-nickel and iron-titanium mineral deposits while the Vermilion fault flight line covered Archean gold mineralization sites. The 63 channel imaging scanner had a spatial resolution of about 9-10 meters and a flight path width of approximately 6.4-7.2 kilometers along three flight lines. Supervised, unsupervised, principal components and inverted principal components analysis and Chebyshev polynomial expansions were used on data collected over two test sites, i.e., the east end of the Archean flight line and the Dunka Pit area, to learn whether or not vegetative stress could be identified in areas with known metallic mineralization. Interpretation of the Dunka Pit test site was abandoned because: 1) the test site was too small; 2) much of the canopy was dead; and 3) the test site was overwhelmed by an adjacent, highly reflective mine dump. At the Archean site, ground spectroradiometer data was collected to assist with the interpretation of the imaging scanner data. The ground data indicated spectral shifts to both longer and shorter wavelengths in vegetation over mineralized compared with unmineralized sites. However, the imaging scanner data did not indicate any evidence of vegetative stress in mineralized areas. At this point, the imaging scanner survey data are useful mainly for discriminating different types of vegetation.
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    Copper-Nickel Grade Maps for the Spruce Road Deposit, South Kawishiwi Intrusion, Duluth Complex
    (University of Minnesota Duluth, 2002-02) Peterson, Dean M
    This report describes the Cu-Ni mineralization of the Spruce Road area in the northern portion of the South Kawishiwi intrusion. The mineralization in the area is defined by > 9,500 assays from approximately 140,000 feet of core from 232 exploration holes drilled by INCO (220 holes), Bear Creek (6 holes), U.S. Bureau of Mines (3 holes), Hanna Mining (2 holes), and Wallbridge Mining (1 hole). Drilling in the Spruce Road area largely occurred during two time periods: the middle 1950s, following the original discovery of Cu-Ni mineralization, and from 1966 to 1973. Assay data from all of the drill holes within the South Kawishiwi intrusion have been compiled by the author into a comprehensive geological and geochemical database. Drill hole assays for the Spruce Road area have been exported out of this database and form the geochemical basis for this report. Preliminary analysis of the drill hole assay data for all of the deposits of the South Kawishiwi intrusion has led to the identification of two main styles of mineralization associated with the base of the intrusion. These mineralization types include: 1) “Open” – vertically extensive (> 450 meters) mineralization with moderate Cu-Ni grade and low Au+PGE grades. Examples of this open style include the Spruce Road, Serpentine, and Dunka Pit deposits. 2) “Confined” – vertically restricted (< 150 meters) mineralization with high Cu-Ni grades and moderate to very high (locally) Au+PGE grades. Examples of the confined style include the Maturi, Maturi Extension, and the Birch Lake deposits. Regional crosscutting relationships indicate that the “Open” style mineralization preceded the “Confined” style. Moreover, the curvilinear nature of the contact between the styles of mineralization is similar to the regional contacts of most of the intrusions of the Duluth Complex and adds further support to this theory.
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    Precious Metals (Pt-Pd-Au-Ag) in Three Copper-Nickel Deposits in the Duluth Complex
    (University of Minnesota Duluth, 1989-11) Hauck, Steven A
    The research work on the precious metals in the three copper-nickel deposits centered on: 1) defining the lateral and vertical extent of the precious metals; and 2) the controls on mineralization, e.g., lithology, structure, etc. While these objectives were the same for each deposit, the methods of investigation at each deposit were dependent upon the amount and quality of previous data available.