Stepovich

The Stepovich is a tungsten mine located in Alaska.

About the MRDS Data:

All mine locations were obtained from the USGS Mineral Resources Data System. The locations and other information in this database have not been verified for accuracy. It should be assumed that all mines are on private property.

Mine Info

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Site Name

Primary: Stepovich

Commodity

Primary: Tungsten
Secondary: Beryllium
Secondary: Antimony
Secondary: Molybdenum

Location

State: Alaska
District: Fairbanks

Land Status

Not available

Holdings

Not available

Workings

Not available

Ownership

Not available

Production

Not available

Deposit

Record Type: Site
Operation Category: Past Producer
Operation Type: Unknown
Years of Production:
Organization:
Significant:

Physiography

Not available

Mineral Deposit Model

Model Name: W skarn

Orebody

Not available

Structure

Not available

Alterations

Alteration Text: Silicified layers in the marble contain pyroxene, hornblende, and quartz (Mertie, 1917).

Rocks

Not available

Analytical Data

Not available

Materials

Ore: Meliphanite
Ore: Molybdenite
Ore: Scheelite
Ore: Stibnite

Comments

Comment (Production): Production Notes = From 1915 to 1916, the Tungsten claim produced 210 tons of ore. During World War I, the production was 10 tons of concentrates thst contained about 65 percent tungsten tri-oxide; 300 tons of sorted ore contained 8 percent tungsten tri-oxide, but only 2 percent was recoverable. Production from 1942 to 1944 was about 98.4 tons of ore (Byers, 1957). There was as small mill on the property that recovered the scheelite concentrate on a Wilfley table.

Comment (Geology): Geologic Description = In 1915, Johnson discovered a scheelite-bearing lode in a crystalline marble bed in schist. The marble has intervals that consist of calcite, pyroxenite, hornblende, and quartz associated with granular scheelite ore, quartz pegmatite, and silicified mica schist (Mertie, 1917; Byers, 1957). The crystalline marble is in discontinuous, irregular bodies roughly parallel to the foliation of the schist. Various descriptions indicate that the limestone may occur as an impure, thin beds, interlayered with other sedimentary rock, or as irregularly shaped, lens-like bodies of relatively pure limestone found at irregular intervals (Gebhardt, 1942).The average thickness of the marble is 2 feet, but it may be as much as 10 feet thick in troughs and crests of folds. Granular scheelite is localized at the intersections of limestone [marble] and scheelite-bearing quartz pegmatite. Typical contact-metamorphic minerals are present, including the beryllium mineral, meliphanite. Green amphibolite forms the footwall of the lode below the 50-foot level of the shaft. The lode generally strikes about N. 70 W. and dips about 35 NW (Byers, 1957). It is offset as much as several tens of feet along steep, northward-striking faults. The weighted average of 32 channel samples in the ore zones was 6.1 percent tungsten tri-oxide, and the average of the ore that was mined was less than 5 percent (Byers, 1957). The richest ore shoots are at the intersections of marble and pegmatite dikes (Berg and Cobb, 1967, p. 220).

Comment (Reference): Primary Reference = Byers, 1957

Comment (Deposit): Model Name = W skarn deposit (Cox and Singer, 1986; model 14a)

Comment (Exploration): Status = Inactive

Comment (Workings): Workings / Exploration = During the period 1915-18, inclined shafts were driven down the dip of the lode. In 1942-44, Cleary Hill Mines Co. sank a 170-foot inclined shaft with levels at 50 feet and 150 feet. Gabhardt (1942) reported shafts 50 and 190 feet deep and about 300 feet apart and a 100-foot tunnel. By 1957, there were 2,000 feet of underground workings (Byers, 1957).

References

Reference (Deposit): Thorne, R.L., Muir, N.M., Erickson, A.W., Thomas, B. I., Hedie, H. E., and Wright, W. S., 1948, Tungsten deposits of Alaska: U.S. Bureau of Mines Report of Investigation 4174, 51 p.

Reference (Deposit): Cobb, E.H., 1975, Mineral resources of Alaska, in Yount, M.E., ed., U.S. Geological Survey Alaska Program, 1975: U.S. Geological Survey Circular 722, p. 37.

Reference (Deposit): Bain, H. F., 1946, Alaska's minerals as a basis for industry: U.S. Bureau of Mines Information Circular 7379, 89 p.

Reference (Deposit): Brooks, A.H., 1916, Antimony deposits of Alaska: U.S. Geological Survey Bulletin 649, 67 p.

Reference (Deposit): Mertie, J.B. Jr., 1917, Lode mining in the Fairbanks District, Alaska: U.S. Geological Survey Bulletin 662-H, p. 403-424.

Reference (Deposit): Cobb, E.H., 1976, Summary of references to mineral occurrences (other than mineral fuels and construction materials) in the Fairbanks quadrangle, Alaska: U.S. Geological Survey Open-File Report 76-662, 174 p.

Reference (Deposit): Cobb, E.H., 1972, Metallic mineral resources map of the Fairbanks quadrangle, Alaska: U.S. Geological Survey Miscellaneous Field Studies Map MF-410, 1 sheet, scale 1:250,000.

Reference (Deposit): Chapman, R.M., and Foster, R.L., 1969, Lode mines and prospects in the Fairbanks district, Alaska: U.S. Geological Survey Professional Paper 625-D, 25 p., 1 plate.

Reference (Deposit): Joesting, H.R., 1943, Report on an experimental magnetometer survey of scheelite deposits in the Gilmore Dome area: Alaska Territorial Department of Mines Miscellaneous Investigation 58-1, 21 p.

Reference (Deposit): Thorne, R.L., Muir, N.M., Erickson, A.W., Thomas, B. I., Hedie, H. E., and Wright, W. S., 1948, Tungsten deposits of Alaska: U.S. Bureau of Mines Report of Investigation 4174, 22 p.

Reference (Deposit): Hill, J.M., 1933, Lode deposits of the Fairbanks District, Alaska: U.S. Geological Survey Bulletin 849-B, p. 29-163.

Reference (Deposit): Byers, F.M., Jr., 1957, Tungsten deposits in the Fairbanks district, Alaska: U.S. Geological Survey Bulletin 1024-I, p. 179-216.

Reference (Deposit): Berg, H.C., and Cobb, E.H., 1967, Metalliferous Lode Deposits of Alaska. U.S. Geological Survey Bulletin 1246, 254 p.

Reference (Deposit): Joesting, H.R., 1943, Report on magnetic and non-magnetic gangue in scheelite ore from Cleary Hill Mines property, Gilmore Dome: Alaska Territorial Department of Mines Prospect Evaluation 58-4, 15 p., 1 map.

Reference (Deposit): Joesting, H.R., 1943, Strategic mineral occurrences in interior Alaska, supplement to pamphlet no. 1: Alaska Territorial Department of Mines Pamphlet 2, 26 p.

Reference (Deposit): Alaska Territorial Department of Mines, 1919, Stepovich tungsten property (history and workings): Alaska Territorial Department of Mines Miscellaneous Investigations 58-1A, 3 p.

Reference (Deposit): Martin, G.C., 1920, The Alaska mining industry in 1918: U.S. Geological Survey Bulletin 712-A, p. 1-52.

Reference (Deposit): Capps, S.R., 1924, Geology and mineral resources of the region traversed by the Alaska Railroad: U.S. Geological Survey Bulletin 755-C, p. 73-150.

Reference (Deposit): Gabhardt, R.C., 1942, Nada Gulch tungsten prospect (Fairbanks): Alaska Territorial Department of Mines Miscellaneous Report 58-5, 11 p.

Reference (Deposit): Allegro, G.L., 1987, The Gilmore Dome tungsten occurrences, Fairbanks mining district, Alaska; a preliminary report: Alaska Division of Geological and Geophysical Surveys Public-Data File 85-53, 50 p., 7 sheets, scale 1:120.

Reference (Deposit): Chapin, Theodore, 1919, Mining in the Fairbanks district: U.S. Geological Survey Bulletin 692-F, p. 321-327.

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