2007-01-032022-02-032007-01-032022-02-03https://hdl.handle.net/11124/69192 copies. USBM #43755; Copy #1: Ventilation door. A small hand operated door is shown to right for a manway. A board walk is laid in center of track. This ventilation door stops air from returning to intake airway and is located in footwall separating vertical shaft and inclined orebody. It is operated by compressed air cylinder shown at upper left. Compressed air is released behind a piston in this cylinder by means of hand lever controlled wires, the levers being located about 100 ft. from door. When door is completely opened a green light is displayed. When compressed air is released a weight pulls door shut again, green light is cut off and a red light is automatically lighted. Copy #2: Figure 38 Ventilation door controlled by compressed air and counterweights. Negaunee Mine is in Marquette County, Michigan.Date scanned: 2001-10-19.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 Negaunee Mine was an underground iron mine near Negaunee, Michigan in the Marquette Range. The Mine opened in 1887 and was later operated by the Cleveland-Cliffs Iron Company. The Mine produced until 1949, when it was classified as exhausted. Cleveland-Cliffs Iron Company was formed with the merger of two major iron mining companies on Michigan 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 miningMine ventilationScenes, undergroundUnderground miningStillImage