The North Cliff Mining Company records consist of correspondence from the Pittsburgh office of the company, written by Thomas M. Howe, Secretary, and H. Holdship, Secretary-Treasurer. Correspondence takes place from October 13, 1858 to May 5, 1875.

Business records of North Butte Mining Company. Core of the collection consists of interoffice correspondence (1906-1923) between the general manager in Butte, Mont., and the president and secretary-treasurer in Duluth, Minn., and New York. The correspondence includes annual and quarterly reports and weekly letters which all describe development work and production in considerable detail. The remainder of the interoffice correspondence deals with general problems of operation of the mines. There is also general correspondence (1906-1907, 1914-1926) with equipment suppliers, other mining companies, and a wide variety of other letters. Of special interest are files of letters inquiring about possible victims of the Granite Mountain and Speculator disasters. In addition, there are a small number of assay reports, ore shipment statements, and estimates of ore reserves; legal documents; lists of mining claims; articles of incorporation; and a scrapbook of clippings about the Granite Mountain Mine explosion (1915) and fire (1917).

Minutes of a special meeting called regarding a resolution authorizing the firm's officers to enter into an agreement with P. F. W. Black and the Shamo Mining Company, correspondence, payrolls, and invoices for supplies.

Company records.

The Crevasse Mountain Mining Company was a Park County, Montana, mining operation. Officers included P.F. Barr, Erastus E. Edgerton, and John Edgerton. This collection (1890-1893) consists of general correspondence, financial records, legal documents, and superintendent reports on mine operations.