Hot Air

Site Name

Primary: Hot Air
Secondary: Hot Air No. 1

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Commodity

Primary: Antimony
Secondary: Gold

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Location

State: Alaska
District: Ketchikan

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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: Simple Sb (veins, pods, etc)

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Orebody

Not available

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Structure

Not available

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Alterations

Alteration Type: L
Alteration Text: The country rocks are silicified and dolomitized.

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Rocks

Not available

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Analytical Data

Not available

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Materials

Ore: Stibnite
Ore: Realgar
Ore: Pyrite
Ore: Kermesite
Gangue: Quartz
Gangue: Calcite

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Comments

Comment (Geology): Age = Late Cretaceous or younger.

Comment (Reference): Primary Reference = Sainsbury, 1957

Comment (Deposit): Model Name = Simple antimony deposit (Cox and Singer, 1986; model 27d)

Comment (Deposit): Other Comments = Soil sampling in the area of this site revealed small stibnite deposits beneath muskeg swamp (Sainsbury, 1957).

Comment (Production): Production Notes = Samples across about 3 feet of the main vein contained 25.67-48.86% Sb, and a shipment of 956 kg of hand-sorted rock from the trenches assayed 44.8% Sb, 12.6% S, 0.5% As, and 14.8% insolubles (Maas and others, 1995, p. 277).

Comment (Geology): Geologic Description = The country rocks near this site are Silurian or Ordovician andesitic and basaltic tuff and agglomerate, and minor interbedded graywacke, argillite, and limestone (Brew, 1996, p. 27, 29). The strata were regionally metamorphosed to greenschist-grade phylliteand semischist in Late Cretaceous time. Their early Paleozoic premetamorphic age assignment is based on a Silurian or Ordovician Pb-U (zircon) isotopic age of a dike that intrudes the bedded rocks. ? the deposit consists of stibnite-bearing fissure veins and irregular replacement masses of stibnite in brecciated and partly dolomitized and silicified limestone (Sainsbury, 1957, p. 163-178; Cobb and Elliott, 1980, p. 23; Maas and others, 1995, p. 277). The limestone is interbedded with gray, calcareous slate and phyllite. The contact between the limestone and phyllite country rocks strikes NW and dips about 30 NE. At the prospect, the country rocks are intricately veined with quartz and calcite stringers, and contain abundant disseminated pyrite. The largest stibnite vein is 3.5 feet thick and about 90 feet long, and consists almost entirely of massive stibnite of radiating acicular and platy crystal habits. The crystals show evidence of mild deformation. Small amounts of realgar and kermesite also are reported at the prospect. A small, highly altered dike that crops out east of the main antimony deposit, contains pyrite, and, reportedly, a little gold.? the veins and associated alteration postdate the Late Cretaceous penetrative metamorphic fabric of the hostrocks. The relatively mild deformation of the stibnite is undated, but it probably postdates, or occurred during a late phase of, the Upper Cretaceous regional metamorphism.

Comment (Workings): Workings / Exploration = The deposit was discovered in 1914. Exploration before 1952 included a 15-foot shaft, a 44-foot shaft, drifts totalling 100 feet, and several trenches (Sainsbury, 1957). Maas and others (1995, p. 277) report a third shaft, of unknown length. Samples across about 3 feet of the main vein contained 25.67-48.86% Sb, and a shipment of 956 kg of hand-sorted rock from the trenches assayed 44.8% Sb, 12.6% S, 0.5% As, and 14.8% insolubles (Maas and others, 1995, p. 277). Samples of disseminated stibnite ore collected by the U.S. Geological Survey contained up to 10,000 ppm Sb (Sainsbury, 1957, p. 173).? A sample of pyrite-rich quartz- and carbonate-veined phyllite and marble collected in 1975 by the U.S. Geological Survey on the coast about 1 mile north-northeast of Caamano Point contained up to 7.5 ppm Au, 2 ppm Ag, 1000 ppm Sb, and more than 1% As (Elliott and others, 1978, loc. 40; Koch and Elliott, 1978, USGS sample 75BG125 [OFR 78-156A]).

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References

Reference (Deposit): Elliott, R.L., Berg, H.C., and Karl, Susan, 1978, map and table describing metalliferous and selected nonmetalliferous mineral deposits, Ketchikan and Prince Rupert quadrangles, Alaska: U.S. Geological Survey Open-file Report, 78-73-B,17 p., scale 1:250,000.

Reference (Deposit): Cobb, E.H., and Elliott, R.L., 1980, Summaries of data on and lists of references to metallic and selected nonmetallic mineral deposits in the Ketchikan and Prince Rupert quadrangles, Alaska: U.S. Geological Survey Open-File Report 80-1053, 154 p.

Reference (Deposit): Sainsbury, C.L., 1957, A geochemical exploration for antimony in southeastern Alaska: U.S. Geological Survey Bulletin 1024-H, p. 163-178.

Reference (Deposit): Koch, R.D., and Elliott, R.L., 1978, Analyses of rock samples from Ketchikan quadrangle, southeastern Alaska: U.S. Geological Survey Open-File Report 78-156-A, 162 p., 1 sheet, scale l:250,000.

Reference (Deposit): Maas, K.M., Bittenbender, P E., and Still, J.C., 1995, Mineral investigations in the Ketchikan mining district, southeastern Alaska: U.S. Bureau of Mines Open-File Report 11-95, 606 p.

Reference (Deposit): Brew, D.A., 1996, Geologic map of the Craig, Dixon Entrance, and parts of the Ketchikan and Prince Rupert quadrangles, southeastern Alaska: U.S. Geological Survey Miscellaneous Field Studies Map MF-2319, 53 p., 1 sheet, scale 1:250,000.

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