White Mountain

Site Name

Primary: White Mountain

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Commodity

Primary: Mercury
Secondary: Antimony

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Location

State: Alaska
District: McGrath

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Land Status

Not available

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Holdings

Not available

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Workings

Not available

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Ownership

Not available

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Production

Not available

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Deposit

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

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Physiography

Not available

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Mineral Deposit Model

Model Name: Hot-spring Hg

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Orebody

Not available

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Structure

Not available

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Alterations

Alteration Type: L
Alteration Text: Extensive dolomitic and chalcedonic alteration; minor dickite, limonite, and calcite alteration.

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Rocks

Name: Dolomite
Role: Host
Age Type: Host Rock
Age Young: Late Ordovician

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Analytical Data

Not available

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Materials

Ore: Cinnabar
Ore: Pyrite
Ore: Stibnite
Gangue: Calcite
Gangue: Chalcedony
Gangue: Dickite
Gangue: Dolomite
Gangue: Limonite

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Comments

Comment (Exploration): Status = Inactive

Comment (Reference): Primary Reference = Sainsbury and MacKevett, 1965

Comment (Workings): Workings / Exploration = Cinnabar mineralization in the White Mountain area was discovered by Jack Egnaty in 1958, while following up panned cinnabar concentrates in the upper Cheeneetnuk River area. The prospects were taken over by Cordero Mining Company (R.F. Lyman family) in 1959 (Jasper, 1961). Trenches were quickly made by Cordero Mining Company and mapped by the U. S. Geological Survey (Sainsbury and MacKevett, 1960, 1965). In 1960, the U.S. Bureau of Mines completed additional trenching and hand tested specific areas with an auger drill (Malone, 1962, 1965). The U.S. Geological Survey visited the property again in 1961 and completed additional mapping of exposed trenches (Sainsbury and MacKevett, 1965). ? After production was initiated in 1964, Cordero Mining Company continued exploration and development of the property through limited diamond drilling, trenching,shaft sinking, and drifting. Their activities continued until the mine ceased operations in 1974 (Conwell, 1975). ? In the South ore zone, a 60 meter long ore body 12 meters wide contained as much as 1 percent mercury. In the Central deposit, an elliptically shaped zone an 10 meter by 13 meter area contains cinnabar mineralization. Drilling confirmed the presence of cinnabar to a depth of 23 meters. The North zone is at least 76 meter long and 3 to 6 meter wide and contains some of the richest ore on the property with grades over 2.5 meter widths exceeding 5 percent mercury.(Sainsbury and MacKevett, 1965; Conwell, 1975).

Comment (Production): Production Notes = Production began in 1964 from a series of small open pits and trenches. Later in 1967 and 1968, shallow underground workings were mined (Conwell, 1971). Originally rich ores were selectively mined and shipped for processing and retortion to a facility in Oregon. In 1971, a small crusher and concentrator were designed to process lower grade disseminated ores on the mine site and to produce a cinnabar crystal concentrate for selected buyers. The ores were mainly retorted at a facility in Oregon. the White Mountain Mine is estimated to have produced about 3,500 flasks (58,300 kilograms) of mercury from 1964 to 1974 (Bundtzen and Conwell, 1982). Operations ceased when mine operator Robert F. Lyman was killed in a heavy equipment accident at the mine site (Conwell, 1975; Bundtzen and Conwell, 1982). The property has remained inactive since.

Comment (Deposit): Model Name = Hot Springs Mercury (Cox and Singer, 1986; model 27a).

Comment (Deposit): Other Comments = See also Mary Margaret (MG027) and Peggy Barbara (MG026) prospects.

Comment (Geology): Geologic Description = The White Mountain Mercury Mine consists of a series of at least three discrete, structurally controlled, cinnabar-dolomite-chalcedony mineralized areas with subordinate to trace amounts of stibnite, pyrite, calcite, and dickite. During development and production activities, the three mineralized areas were designated the 'South', 'Center', and 'North' ore zones (Sainsbury and MacKevett, 1965). The cinnabar deposits are distributed along a belt approximately one kilometer wide and three kilometers long near the northwest side of the active strand of the Farewell-Denali Fault system (Gilbert, 1981). In the White Mountain Mine area, this fault system juxtaposes Cambro-Ordovician ollitic limestone on the southeast against Ordovician mudstone on the northwest (Gilbert, 1981). Both units are part of the Nixon Fork subterrane (Decker and others, 1994). The cinnabar ore bodies are found near individual strands of the Farewell-Denali fault, generally where shale is faulted against limestone (Sainsbury and MacKevett, 1960, 1965). All of the known ore zones strike from N25W to N40E and dip steeply to vertically, parallel to the Farewell-Denali fault system. ? In all three mineralized areas, cinnabar occurs as dark-red crystals coating open-space fillings in brecciated dolomite, as 'paint' on breccia surfaces, and as irregular veinlets of nearly pure cinnabar. Dolomite replacement is a conspicuous feature of the ore zones and in addition, significant amounts of chalcedonic alteration also occurs in the north ore zone. These features, coupled with observations of ancestral spring activity in other nearby deposits such as the Peggy Barbara (MG026) and Mary Margaret Prospects (MG027) and isotopic data from White Mountain Mine (Gray and others, 1997) suggest a mineralogical origin in a hot springs environment. Crystalline cinnabar was especially well developed in the North ore zone.? In the South ore zone a 60 meter long orebody 12 meters wide contained as much as 1 percent mercury. In the Central deposit, an elliptically shaped, 10 meter by 13 meter zone of cinnabar mineralization was intersected to a depth of 23 meters. The North zone is at least 76 meters long and 3 to 6 meters wide, and contains some of the richest ore with grades over 2.5 meter widths exceeding 5 percent mercury (Sainsbury and MacKevett, 1965; Conwell, 1975).

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References

Reference (Deposit): Cobb, E.H., 1976, Summary of references to mineral occurrences (other than mineral fuels and construction materials) in the Iliamna, Lake Clark, Lime Hills, and McGrath quadrangles, Alaska: U.S. Geological Survey Open-File Report 76-485, 101 p.

Reference (Deposit): Cobb, E.H., 1972, Metallic mineral resources map of the McGrath quadrangle, Alaska: U.S. Geological Survey Miscellaneous Field Studies Map MF-379, 1 sheet, 1:250,000 scale.

Reference (Deposit): Jasper, M.W., 1961, Report on White Mountains cinnabar prospect of Cordero Mining Company: Alaska Division of Mines and Minerals Prospect Examination 74-1, 17 p.

Reference (Deposit): Sainsbury, C.L. and MacKevett, E.M., Jr., 1965, Quicksilver deposits of southwestern Alaska: U.S. Geological Survey Bulletin 1187, 89 p.

Reference (Deposit): Malone, Kevin, 1965, Mercury in Alaska, in Mercury potential of the United States: U.S. Bureau of Mines Information Circular 8252, p. 31-59.

Reference (Deposit): Conwell, C.N., 1971, Mercury mining revival in Alaska despite poor access and climate: World Mining Magazine, vol. 23, no. 7, p. 34-38.

Reference (Deposit): Nokleberg, W.J., Bundtzen, T.K., Berg, H.C., Brew, D.A., Grybeck, D.J., Robinson, M.S., Smith, T.E., and Yeend, W., 1987, Significant metalliferous lode deposits and placer districts of Alaska: U.S. Geological Survey Bulletin 1786, 104 p.

Reference (Deposit): Bundtzen, T.K., and Conwell, C.N., 1982, Madhatters of the Kuskokwim Quicksilver Mines, in Larson, Frank, ed., Alaska Mines and Geology Bulletin (Misc. Paper 13): Alaska Division of Geological and Geophysical Surveys, vol. 31, no. 1, p. 1-5.

Reference (Deposit): Decker, J., Bergman, S.C., Blodgett, R.B., Box, S.E., Bundtzen, T.K., Clough, J.G., Coonrad, W.L., Gilbert, W.G., Miller, M.L., Murphy, J.M., Robinson, M.S., and Wallace, W.K., 1994, Geology of southwestern Alaska, in Plafker, G. and Berg, H.C., eds., The Geology of Alaska: Boulder, Colorado, Geological Society of America, The Geology of North America, v. G-1, p. 285-310.

Reference (Deposit): Conwell, C.N., 1975, Review of Alaska's mineral and energy resources: production and activity statistics, in Schaff, R.G.,ed., Alaska Division of Geological and Geophysical Surveys Biennial report, 1974-75, 53 pages.

Reference (Deposit): Gilbert, W.G., 1981, Preliminary geologic map of the Cheeneetnuk River area, Alaska: Alaska Division of Geological and Geophysical Surveys Open-File Report 153, 19 pages, 2 sheets, 1:63,360 scale.

Reference (Deposit): Gray, J.E., Gent, C.A., Snee, L.W., and Wilson, F.H., 1997, Epithermal mercury-antimony and gold-bearing vein lodes of southwest Alaska, in R.J. Goldfarb, and L.D. Miller, eds., Mineral Deposits of Alaska: Economic Geology Monograph 9, p. 287-305.

Reference (Deposit): Malone, Kevin, 1962, Mercury occurrences in Alaska: U.S. Bureau of Mines Circular 8131, 57 p.

Reference (Deposit): Sainsbury, C.L., and MacKevett, E.M. Jr., 1960, Structural control in five quicksilver deposits in southwestern Alaska, in Geological Survey Research in 1960: U.S. Geological Survey Professional Paper 400-B, p. B35-B38.

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