The Stillwater Complex and adjacent rocks, located within the West Stillwater mining district and to its east and west, were known to contain copper, nickel, and chromium as early as the 1880s. Deposits of platinum-group elements, iron, and aluminum were recognized later. The history of the exploration and development of the mines in the area is closely tied to wartime demands for copper and chromium (Page et al. 1985).
During World War I, the Stillwater Complex was intensively explored for chromite (chrome ore). The complex is a narrow area that runs southeast from the Boulder River to just east of the Stillwater River on the northeastern portion of the Beartooth Mountain Range. Chromite was first discovered in the location in the 1880s. It was important during wartime because it hardens other metals and prevents rust in iron and steel products. After the end of World War I, demand for chromite plummeted and most of the mining ceased. Demand rose again during World War II, and the Anaconda Copper Mining Company worked the Benbow and Mouat mines during the war, building extensive work camps and mills. The area continued to be mined sporadically until the 1960s (Porsche 1984).
The West Stillwater district is located in Sweetgrass County and is bounded on the east and south by Stillwater County. The West Fork of the Stillwater River flows through the southern part of the district. Most of the Boulder River region is underlain by Archean crystalline rock involved in the Beartooth uplift. The northern margin of the area contains the westward-extending tongue of the Stillwater complex, which is overlain by Cambrian quartzites, shales, and limestones. The Archean gneisses and schists to the south have been covered and intruded by Tertiary rocks, which include basic and acidic andesites, dacites, basalt, and quartz monzonite (Reed 1950).
Copper-nickel exploration focused on the Basal series, the metasedimentary rocks immediately below the complex, and on the lower parts of the Ultramafic series. Exploration, development, and mining of chromite was restricted to the Peridotite zone of the Ultramafic series because economically significant chromite concentrations do not occur elsewhere within the Stillwater Complex (Page et al. 1985).
In 1883 Jack Nye and Jimmy and Jonas Hedges discovered sulfide-rich rocks associated with the Basal series of the Stillwater Complex. The Stillwater Mining Company was incorporated the next year, and in 1885 Nye sold his quartz and placer claims to the mining company, which then sold the claims to the Minneapolis Mining and Smelting Company. The construction of Nye City (Nye district) began soon after. The population of Nye City peaked at 300-400 people in 1887. By the early 1930s, sulfide occurrences had been defined at Mountain View and Benbow (Nye mining district), Crescent Creek (West Stillwater mining district), Placer Basin (Natural Bridge mining district), and the Boulder River (Page et al. 1985).
In 1887 a government survey revealed that Nye City was actually on Crow Indian Reserve land, so mining operations ceased for a time. In 1890 the Crows ceded the land, legalizing mining and claim staking. In 1904 a trial shipment of ore to a smelter in Nebraska yielded poor values that did not warrant production. The mines were not developed again until the World War I period, when Bill Mouat began development work. About 8,000 feet of tunneling were dug during this initial development (Page et al. 1985).
T. C. Benbow, prospecting in the Stillwater River Valley where he had settled in 1892, discovered large deposits of chrome there in 1904. The deposit extended from the Boulder River in Sweet Grass County to Fishtail Creek in Stillwater County. During World War I there was new development at the Benbow mine (in the Nye mining district) and at the claims of A. E. Fry and W. Dillon on the Boulder Plateau, and in the Gish mine area (in the Boulder River mining district). The domestic chromite could not compete with foreign, however. In the 1920s Benbow built roads and installed machinery for developing the ore, but development work was halted by the stock market crash of 1929. In the early 1930s the Chromium Products Corporation formed and bought interests in the area. At the start of World War II the government arranged with the Anaconda Copper Mining Company to open the mines on a non-profit basis. Roads and mills were built, the deposits were opened, and towns erected for workers at three sites: the Benbow and Mouat mines on the upper Stillwater (in the Nye mining district) and the Red Lodge deposit. The company produced 91,164 long tons of concentrates from the Benbow and Mouat mines (none of the material from the Gish mine was milled). This mining boom, with jobs for over 1,000 workers, lasted only until less expensive chrome was once again available from Africa. The War Assets Administration liquidated most of the buildings and machinery at the site. At the start of the Korean War, the American Chrome Company contracted with the U. S. government to mine 900,000 tons of chromite at the Mouat mine. The area was again abandoned after the completion of the contract in 1961 (Burlingame and Toole 1957; Page et al. 1985; Amos 1985).
Identified resources of chromite in the Mouat (Nye District) and Benbow (Stillwater District) mine areas represent about 80% of the identified chromite reserve in the United States. Little if any chromite production occurred in the West Stillwater area (Page et al. 1985).
BOUNDARIES OF THE DISTRICT
Since the 1930s the area with ores containing chromite has been known as the Stillwater Complex. This is a narrow band of chromite-bearing ores that extends to the east and west of the actual mining district boundaries. The most extensive mining activity involving chromite actually occurred in the Nye City area to the east (the Benbow and Mouat mines).
Schafer (1937) defines the West Stillwater district as the area that lies between the West Stillwater and the Stillwater River. The upland is a northward extension of Lake Plateau and its crestal elevation is about 8,500 feet.
The Stillwater Chromite Complex is described by Wimmler (1948) which defines the mining area relatively precisely (Figure 1). This is shown on the AMRB (1994) map along with the boundaries of the district as described by Schafer (1937).
HISTORIES OF SELECTED MINES
The Bluebird claims were located on the west side of Cathedral Creek, a tributary of the West Fork of the Stillwater River. The claims were located in 1939, but little had been done to prospect the chromite deposits until the early 1940s, when the Bureau of Mines began to sample the ore (Wimmler 1948).
The Taylor-Fry group of claims was located in 1917, 1918, and 1919 by a Mr. Dillon for a Mr. Fry and were subsequently abandoned and relocated several times. After Fry died in 1938, his two sons Clem and Bryan took over and were later joined by W. A. Taylor. The group of claims consisted of 11 lode claims and a placer claim located along the main chromite band, plus 10 side claims. They were located on the west side of the West Fork of the Stillwater River and extended about four miles from an elevation of 6800 feet to 9500 feet (the legal location is given as sec. 17, T5S, R14E). No work on the mines was done before the early 1940s (Wimmler 1948).
Aaberg, Stephen A.
1993 "Stillwater Bridge Project Area Archaeological Survey Results", Montana Department of Transportation Project # BR9048(11), Helena.
Abandoned Mine Reclamation Bureau (AMRB)
1994 Mining districts of Montana. Maps 1:100,000 and Map #94-NRIS-129. Compiled and edited by Joel Chavez. Prepared by Montana State Library Natural Resource Information System (NRIS) for Montana Department of State Lands. Helena
1985 "Baseline Study - Historical Resources, Stillwater Mining Company 161 kV Transmission Line." Montana Power Company.
Burlingame, Merrill G. and K. Ross Toole
A History of Montana
, vol. 1. New York: Lewis Historical Publishing Co. GCM Services
1988 "Addendum to Cultural Resource Field Inventory Anaconda Stillwater Complex Project" prepared for Hydrometrics, Inc., Helena. Addendum to study prepared by Western Cultural Resource Management, Boulder for Camp, Dresser & McKee, 1981.
Page, Norman J. et al.
1985 "Exploration and Mining History of the Stillwater Complex and Adjacent Rocks," in Gerald K. Czamanske and Michael L. Zientek, eds.,
The Stillwater Complex, Montana: Geology and Guide.
Montana Bureau of Mines and Geology, Special Publication 92.
Peoples, Joe Webb
1933 "Stillwater Igneous Complex, Montana",
(abst.) Am. Mineralogist
, Vol. 18, No. 3, p. 117.
1984 "Cultural Resource Inventory, Stillwater Mining Company 161-kV Transmission Line." Montana Power Company.
Reed, Glenn C.
1950 "Mines and Mineral Deposits (Except Fuels) Park County, Mont." U. S. Bureau of Mines Information Circular 7546.
Rossillon, Mitzi and Mary McCormick
1991 "Cultural Resource Inventory of the Stillwater River Road Project on Montana Forest Highway 83, Stillwater County", prepared for Western Federal Lands Highway Division, Vancouver, Washington.
Schafer, Paul A.
1937 "Chromite Deposits of Montana", Montana Bureau of Mines and Geology, Memour #18.
Wimmler, N. L.
1948 "Investigation of Chromite Deposits of the Stillwater Complex, Stillwater and Sweetgrass Counties, Mont." Bureau of Mines, Reports of Investigations 4368.