In 1915 three mines combined into the Jacket-Crown Point-Belcher Mines Company which in turn became part of the United Comstock Mining company in 1920. Collection contains records of operation including weekly reports from the mine superintendent to H.D. Fry; and assay records for the Belcher and Crown Point mines; and the Santiago, Vivian, Mexican, and Eureka mills.

Located on the Carson River, the Woodworth Mill was built in 1864 and, by 1869, contained 24 stamps, 12 pans, and had a capacity of 40 tons per day. In 1871, James G. Fair and John W. Mackay of the Pacific Mill and Mining Company purchased the mill. The Woodworth Sluice was one of the longest sluices ever built. Collection contains employee payment slips for August and September 1874 for work on company flumes and sluices signed by W. H. Armstrong.