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Detailed Geologic Maps of Recently Active Copper Mines, Houghton and Keweenaw Counties, Michigan
Henry Rowland Cornwall
J. J. Runner
A. A. Stromquist
R. W. Swanson
W. A. White
出版
1949
URL
http://books.google.com.hk/books?id=5665AQAACAAJ&hl=&source=gbs_api
註釋
"Study of the accessible mine workings of the Michigan copper district was undertaken by the Geological Survey in November 1912, as part of its contribution to the search for minerals needed in the war effort. The immediate purpose of the 'Michigan study was to test the usefulness of detailed geologic mapping as an aid to underground development in this district. Although such studies had been carried out previously in individual mines without notable success, it was -felt that very detailed napping of a large number-of workings might be more productive of useful information. A little more than 50 miles of mine drifts were mapped in considerable detail, and much of the information iis recorded on the accompanying maps."--Introduction.
