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Title: Tests of rock cores, Duluth-Vermillion study area, Minnesota
Authors: Space and Missile Systems Organization (U.S.)
United States. Air Force. Systems Command.
Crisp, Robert W.
Saucier, K. L.
Keywords: Duluth-Vermillion study area, Minn.
Petrographic examination
Rock cores
Rock properties
Rock tests
Publisher: Concrete Laboratory (U.S.)
Engineer Research and Development Center (U.S.)
Series/Report no.: Miscellaneous paper (U.S. Army Engineer Waterways Experiment Station) ; C-70-9.
Description: Miscellaneous paper
Abstract: Laboratory tests were conducted on rock core samples received from six core holes in the Duluth-Vermillion study area of Koochiching, Lake, and St. Lois Counties, Minnesota. Results were used to determine the quality and uniformity of the rock to depths of 200 feet below ground surface. The rock core was petrographically identified as predominantly tonalite and gabbro, with relatively minor amounts of amphibolite, granite, and gneiss. Many specimens contained fractures ranging in orientation from vertical to horizontal. Several specimens contained bands and/or contacts with other types of rock. Evaluation on a hole-to-hole basis indicates the tonalite represented by specimens from Hole DV-CR-19 to be quite uniform and very competent. 'This material should offer very good possibilities as a competent hard rock medium. The tonalite, medium-grained gabbro, and granite and granitic gneiss representing Holes DV-CR-17, -40, and -9, respectively, exhibited physical properties typical of relatively competent to very competent material, and all should offer reasonably good possibilities as competent media. The coarse-grained gabbro from Hole DV-CR-24, and the amphibolite and tonalite from Hole DV-CR-39, were generally marginal (compressive strength 8,ooo through 12,000 psi) to relatively competent (compressive strength >12,000 psi) in quality, with only one specimen (DV-CR-39, Specimen 7, an amphibolite) yielding an ultimate uniaxial compressive strength characteristic of incompetent rock. Evaluations have been confined to specimens from single holes and, therefore, more extensive investigation will be required.
Rights: Approved for public release; distribution is unlimited.
Appears in Collections:Miscellaneous Paper

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