2007-01-032022-02-032007-01-032022-02-03https://hdl.handle.net/11124/7387H-19; Self-contained drilling unit. Drilling 6-foot holes in frozen ground. (See H-14). Portsmouth Mine, The M. A. Hanna Company, Ironton, Minnesota. - Floyd G. Anderson - Jan. 30, 1948.Held in the Russell L. and Lyn Wood Mining History Archive, Arthur Lakes Library, Colorado School of Mines.Donor: United States Bureau of Mines.Date scanned: 2002-6-12.Rights management statement available at: http://library.mines.edu/digital/rights.htmlM. A. Hanna CompanyIron mines and miningMinersMiningScenes, snowStillImage