Collins, George2007-01-032022-02-032007-01-032022-02-03http://hdl.handle.net/11124/9967Iron City Mill below Blackhawk. Iron mill near Blackhawk, Idaho Springs.Date scanned: 2000-10-19.Identifier: SC729.Unmounted; text on verso.Held in the Russell L. and Lyn Wood Mining History Archive, Arthur Lakes Library, Colorado School of Mines.Photograph of the Iron City Mill showing the buildings at the mill, railroad tracks and cars, equipment and piles of bags. The Iron City Mill, which was located just south of Black Hawk, operated for many years. The exact dates of operation for this mill have not been determined, but it was still in use when this photograph was taken in the early 1900s. The Iron City mill was a twenty-five stamp mill, and it was one of at least fifteen stamp mills operating in the Black Hawk area in 1899. The photograph shows the ore carts going into the upper level of the mill where the rocks were pulverized by the twenty-five stamps, which were heavy iron shoes that were lifted by a cam wheel and dropped on the ore-bearing rocks. Each stamp weighed between 500 and 700 pounds, and the stamps were dropped 27 to 35 times a minute. The noise made by the stamps was deafening. Mercury was used to amalgamate the gold. The pulverized ore was washed onto sloping mercury-coated copper plates, a ...Rights management statement available at: http://library.mines.edu/digital/rights.htmlGold ore processing plantsStillImage