DNR Report 93: 1977; Mineral Resources of a Portion of the Duluth Complex and Adjacent Rocks in St. Louis and Lake Counties, Northeastern Minnesota

Abstract extracted from page 1 of the report:

ABSTRACT The Minerals Division of the Minnesota Department of Natural Resources completed a resource study of an area near the basal contact of the Duluth Complex in St. Louis and Lake Counties of northern Minnesota. A total of 324 of the 500 available drill holes were used in the resource study. The resource estimate was accomplished using a standard perpendicular bisector method of polygon construction. The total area of the polygons was 42.2 square miles. Three tonnage estimates were made in this study. The first estimate is of material with a minimum thickness of 50 feet and > .5% copper, secondly, material with a minimum thickness of 50 feet > .10% Ti02, and finally a 100 foot minimum thickness of near-surface material > .25% copper. The estimate of material > 0.5% copper is over 4.4 billion tons. Near-surface mineralization > 0.25% copper is over one billion tons, and over 220 million tons of > 10% Ti02 is estimated. Thirty-six percent of the total holes intersected at least 50 feet of > 0.5% capper and their polygons represented 31% of the total area measured. The average grade of the 4.4 billion tons is estimated at 0.66% copper with a copper to nickel ratio of 3.3:1.




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Report 93: Mineral Resources of a Portion of the Duluth Complex and Adjacent Rocks in St. Louis and Lake Counties, Northeastern Minnesota; Cu-Ni resource estimate for 42 sq. miles in T57N-62N R10W-14W; references.
(63 pages, 8.5 x 11 inches, 2.4 MB)
Authors: W.H. Listerud and D.G. Meineke

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