The Basin Mining Company was a Granite County, Montana, gold mining company, with head offices in St. Louis, Missouri. Records include interoffice correspondence (1903-1923), general correspondence (1903-1925), records of a court case (1907), minor financial records, organizational records (1906-1922), and miscellany.

The First National Bank of Helena, Montana, was organized by Samuel T. Hauser and T.H. Kleinschmidt, in 1866. Prominent officers included: John S. Atkinson, D.C. Corbin, and E.W. Knight, cashiers; George H. Hill, assistant cashier. The bank was in receivership from its closing in 1896 until 1903. Records (1865-1903) include correspondence, financial volumes, legal documents, and organizational records of the bank and of its receiver, Eugene S. Wilson.

Paul Fusz was a Philipsburg, Montana, mining investor and businessman. Papers (1903-1912) include correspondence, court papers, legal documents, and reports relating to various mining ventures, including the Granite-Bimetallic Consolidated Mining Company. There are subgroups for the Rimini Mining Syndicate and the United Confederate Veterans.

George H. Hill (d. 1922) was a Helena, Montana, businessman and executor of the Samuel T. Hauser Estate. Collection (1885-1936) deals mostly with the mining industry, and includes general correspondence, financial records, legal documents, subject files, miscellany. It includes subgroups for George H. Hill (1885-1929), Florence Child Hill (1907-1936), and the Glacier Peak Mining and Smelting Company (1906-1921).

The Trout Mining Company produced manganese oxide for batteries. Records consist of scattered correspondence (1939-1951); payroll records (1956-1959), orders for equipment and supplies (1946-1953); production records, including a sample book (1958) for the Blaine Mine; reports; and miscellany, including field survey books (1936-1938).