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Title: Tests of rock cores, Michigame study area, Michigan
Authors: Space and Missile Systems Organization (U.S.)
United States. Air Force. Systems Command.
Crisp, Robert W.
Keywords: Michigamme study area, Michigan
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-70-10.
Description: Miscellaneous paper
Abstract: Laboratory tests were conducted on rock core samples received from six core holes in the Michigamme study area of Marquette and Baraga Counties near Sawyer Air Force Base, Michigan. 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 predominately tonalite, potash granite, and amphibolite, with relatively minor amounts of biotite schist and pegmatite. Most specimens contained fractures which ranged in orientation from horizontal to vertical. Several specimens contained well-developed systems of fracture. Evaluation on a hole-to-hole basis indicates the potash granite removed from Hole MG-CR-2A and the gneissic tonalite and amphibolites removed from Holes MG-CR-26 and -28 to be relatively competent to very competent rock. These holes represent materials which should offer good possibilities as competent, hard rock media. Hole MG-CR-18 yielded specimens of potash granite, tonalite, and amphibolite. This variety of materials exhibited physical characteristics generally representative of margi.nal to good quality rock, and should offer some possibility as a competent hard rock medium, provided the single zone of incompetent rock is not disqualifying factor. The tonalites, amphibolites, and potash granites representative of Holes MG-CR-10 and -54 were generally fractured and exhibited physical characteristics typical of rock of lower quality than that required of competent media. The above evaluations have been based on somewhat limited data, and, therefore, more extensive investigation will be required in order to fully define the individual areas under consideration.
Rights: Approved for public release; distribution is unlimited.
Appears in Collections:Miscellaneous Paper

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