Cirque

The Cirque is a zinc, lead, copper, and silver 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

Satelite View

MRDS mine locations are often very general, and in some cases are incorrect. Some mine remains have been covered or removed by modern industrial activity or by development of things like housing. The satellite view offers a quick glimpse as to whether the MRDS location corresponds to visible mine remains.

Site Name

Primary: Cirque

Commodity

Primary: Zinc
Primary: Lead
Primary: Copper
Primary: Silver

Location

State: Alaska
District: Bonnifield

Land Status

Not available

Holdings

Not available

Workings

Not available

Ownership

Not available

Production

Not available

Deposit

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

Physiography

Not available

Mineral Deposit Model

Model Name: Massive sulfide, kuroko

Orebody

Not available

Structure

Not available

Alterations

Alteration Type: L
Alteration Text: Pyrite and sericite.

Rocks

Role: Host
Age Type: Host Rock
Age Young: Late Devonian

Analytical Data

Not available

Materials

Ore: Sphalerite
Ore: Pyrite
Ore: Galena
Ore: Chalcopyrite
Gangue: Sericite
Gangue: Quartz

Comments

Comment (Exploration): Status = Active

Comment (Geology): Age = Mineralization was probably syngenetic with the Upper Devonian host rocks.

Comment (Reference): Primary Reference = the Northern Miner, 1999, v.85, no. 24

Comment (Workings): Workings / Exploration = Surface exploration mostly includes soil grids, rock-chip sampling and trenching. In 1994, a ground geophysical survey delineated a 670-meter-long electromagnetic anomaly coincident with the Dol zone. There was unknown amount of drilling in 1999. Surface samples over a 2.4 meter width at the Discovery zone contain an average value of 3.84% zinc, 2.76% lead, and 0.49% copper, plus 3.73 grams gold and 98.5 grams silver per tonne. The Dol zone highlights include a 1-meter chip sample that assayed 5.57% zinc, 2.24% lead, and 0.31% copper, and 0.41 gram gold and 33 grams silver per tonne (The Northern Miner, v. 85, no. 24).

Comment (Geology): Geologic Description = The country rocks at the Cirque prospect are Upper Devonian? felsic metavolcanic rocks, chiefly dark- to medium-gray, fine- to medium-grained schist and phyllite, that locally contain relict phenocrysts of quartz, orthoclase, and plagioclase (Wilson and others, 1998). The deposit generally consists of stratiform layers of massive sulfides, chiefly pyrite, chalcopyrite, galena, and sphalerite. Two ore bearing zones have been identified: the Discovery and Dol zones. The Discovery zone is hosted in carbonaceous shale and appears to follow a contact with rhyolite schist. The sulfide layer is massive to banded and can be traced in outcrop for about 20 meters with widths up to 2.8 meters. The zone remains open in both directions but is covered by talus and scree. Surface samples over a 2.4 meter width at the Discovery zone contain an average value of 3.84% zinc, 2.76% lead, and 0.49% copper, plus 3.73 grams gold and 98.5 grams silver per tonne. The Dol zone is in dolomite interbedded with shale. The zone has been traced in scattered outcrops for about 200 meters. All outcrops sampled returned anomalous base and precious metal values. Highlights include a 1-meter chip sample that assayed 5.57% zinc, 2.24% lead, and 0.31% copper, and 0.41 gram gold and 33 grams silver per tonne (The Northern Miner, v. 85, no. 24).

Comment (Deposit): Model Name = Kuroko massive sulfide (Cox and Singer, 1986; model 28a)

References

Reference (Deposit): Anonymous, 1999, Cirque: The Northern Miner, v. 85, no. 24, p. 4.

Reference (Deposit): Wilson, F.H., Dover, J.H., Bradley, D.C., Weber, F.R., Bundtzen, T.K., and Haeussler, P.J., 1998, Geologic map of central (interior) Alaska: U.S. Geological Survey Open-File Report 98-133, 17 p., 2 sheetsm, scale 1:500,000.

The Top Ten Gold Producing States

These ten states contributed the most to the gold production that built the West from 1848 through the 1930s. The Top Ten Gold Producing States.