Petersen, Max S.2007-01-032022-02-032007-01-032022-02-03http://hdl.handle.net/11124/6458Date scanned: 2002-05-16.USBM #57732; "Manual Blasting Switch" used at the Mather Mine. The Cleveland-Cliffs Iron Company, Ishpeming, Marquette County, Michigan. Standard 2-pole, double throw, safety switch (fuses "plugged" with copper strip) altered so that it can be closed in the upper (blasting) position only when the door is unlocked and opened. Can be locked only in lower position which shorts leading wire to blast. Plug to fit receptacle also locked in box in position shown. Oct. 1944 / Max S. Petersen. See also U252.Held in the Russell L. and Lyn Wood Mining History Archive, Arthur Lakes Library, Colorado School of Mines.Donor: United States Bureau of Mines.The Mather Mine near Ishpeming was operated by the Cleveland-Cliffs Iron Company. It was the last underground iron mine operating in Michigan and finally closed in 1979. Cleveland-Cliffs Iron Company was formed with the merger of two major iron mining companies on Michigan's Marquette Range in 1891. The Company had a number of mines operating in the Upper Peninsula by the outbreak of World War I. By the 1940s the high grade iron ores mined underground were becoming depleted. The Company developed a process to concentrate low grade ores into iron ore pellets in the 1950s, and C.C.I.C.'s last underground iron mine closed in 1979.Rights management statement available at: http://library.mines.edu/digital/rights.htmlCleveland-Cliffs Iron CompanyIron mines and miningBlastingUnderground miningStillImage