Abstract Abstracts, circa 1845-circa 1929, compiled by Calumet and Hecla in support of the publication of USGS Professional Paper 144. Files contain information abstracted from a variety of sources including newspaper and magazine articles, published stockholder reports, mine superintendent reports, state and federal geological surveys, and unpublished company reports. Many files include blueprint maps of underground workings, surface buildings and property ownership. More than one hundred mines and...