The Hope Mining Company was a silver mining company located in Philipsburg, Montana. Records consist of interoffice correspondence (1907-1913), general correspondence (1907-1913), minor financial records (1907-1911), articles of incorporation and minutes (1907), assay reports (1907-1910) and a field survey book (1909)

John Lucas was mine superintendent of the Granite-BiMetallic Consolidated Mining Company and other mining operations in the Philipsburg, Montana, area. Papers (1903-1916) include general correspondence with Paul A. Fusz, Charles D. McLure, and others about the operation of the mines. There are also materials on the Montana Democratic Party and the United Confederate Veterans.

Records of the Philipsburg Mining Company, of Philipsburg, Montana, consist of interoffice correspondence between the Philipsburg office, the St. Louis office, and the sales office in Cincinnati; general correspondence; financial records, consisting primarily of vouchers; production records, including assay reports and manganese ore shipment records; accident reports; and miscellany.

The Royal Mining Company, originally the Royal Gold and Silver Mining Company, was located near Philipsburg, Montana. Records include correspondence (1899-1921) between company secretary W.M. Bickford and various stockholders and officers; assay reports; financial records; mining leases (1910-1921); and organizational records (1891-1912).

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).