Calumet and Hecla Smelters, 1900: Photographs of the Calumet and Hecla smelters, used with the copper industry, taken in 1900. From the American Memory collection of the Library of Congress.
Calumet and Hecla Stamp Mills, 1906: A series of photographs of the Calumet and Hecla stamp mills, taken in 1906. From the American Memory collection of the Library of Congress.