Eldorado

The Eldorado is a gold 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: Eldorado
Secondary: Alaska Free Gold Mining Co.

Commodity

Primary: Gold

Location

State: Alaska
District: Willow Creek

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: Low-sulfide Au-quartz vein

Orebody

Not available

Structure

Not available

Alterations

Alteration Type: L
Alteration Text: The vein and host are oxidized to depths of 30 ft (Capps, 1915). Wall-rock alteration within a few inches of the veins is intense, but seldom extends more than 10 to 12 inches beyond the quartz filling. Sericitization and carbonate alteration predominate, but there is some pyritization and in the outer parts of the alteration zone chloritization is present (Ray, 1954).

Rocks

Not available

Analytical Data

Not available

Materials

Ore: Gold
Gangue: Quartz

Comments

Comment (Geology): Age = Late Cretaceous or younger; vein cuts the Late Cretaceous Willow Creek Pluton.

Comment (Exploration): Status = Inactive

Comment (Reference): Primary Reference = Capps, 1915

Comment (Geology): Geologic Description = Capps (1915) reported a 1 to 18 inch wide gougy quartz vein cuts the Late Cretaceous Willow Creek Pluton. The quartz vein strikes N 24 W, and dips 36 W, and consists of solid quartz, associated with some clayey gouge. The Willow Creek Pluton is a zoned pluton: the outer part consists of hornblende quartz diorite and lesser hornblende tonalite; the core consists of hornblende-biotite granodiorite, and lesser hornblende-biotite quartz monzodiorite and biotite quartz monzonite. The vein and host are oxidized to depths of 30 ft (Capps, 1915). Wall-rock alteration within a few inches of the veins is intense, but seldom extends more than 10 to 12 inches beyond the quartz filling. Sericitization and carbonate alteration predominate, but there is some pyritization and in the outer parts of the alteration zone chloritization is present (Ray, 1954).

Comment (Deposit): Model Name = Low-sulfide Au-quartz veins (Cox and Singer, 1986; model 36a)

Comment (Workings): Workings / Exploration = Developed by several large open cuts and an inclined 30 ft adit. In 1911 a few tons of ore from the property was milled in the mill of the Alaska Gold Quartz Mining Co., (the Independence mine - ARDF number AN001) and yielded the first gold produced from this mine. Reportedly in 1912 about 100 tons of ore was dragged down a trail to a point from which it could be trammed to the mill (Capps, 1915). Stoll (1997) indicated that in the summer of 1939 the old shaft was reopened and retimbered by Alaska Pacific Consolidated Mining Co., and shipments of near-surface quartz were sent down to the old mill. In July the following summer the shaft was deepened, staying beneath the Eldorado vein. A raise to the vein and a drift northward along it were driven, finding ore with gold values good enough for the mill. By the summer of 1941 further exploration at Eldorado was 'outranked' by other ore-hunting plans.

Comment (Production): Production Notes = A few tons milled in 1911, about 100 tons milled in 1912 (Capps, 1915). Undetermined amount of ore trammed to the mill in 1939 and 1940.

References

Reference (Deposit): Cobb, E.H., 1979, Summary of references to mineral occurrences (other than mineral fuels and construction materials in the Anchorage quadrangle, Alaska: U.S. Geological Survey Open-File Report 79-1095, 184 p.

Reference (Deposit): MacKevett, E.M., Jr., and Holloway, C.D., 1977, Map showing metalliferous mineral deposits in the western part of southern Alaska: U.S. Geological Survey Open-File Report 77-169-F, 38 p., 1 sheet, scale 1:1,000,000.

Reference (Deposit): Cobb, E.H., 1972, Metallic mineral resources map of the Anchorage quadrangle, Alaska: U.S. Geological Survey Miscellaneous Field Studies Map MF-409, 1 sheet, scale 1:250,000.

Reference (Deposit): MacKevett, E.M., Jr., and Holloway, C.D., 1977, Map showing metalliferous and selected non-metalliferous mineral deposits in the eastern part of southern Alaska: U.S. Geological Survey Open-File Report 77-169-A, 99 p., 1 sheet, scale 1:1,000,000.

Reference (Deposit): Stoll, W.M., 1997, Hunting for gold in Alaska's Talkeetna Mountains 1897-1951: Greensburg, Pennsylvania, Henry Printing, 301 p.

Reference (Deposit): Capps, S.R., 1915, The Willow Creek District, Alaska: U.S. Geological Survey Bulletin 607, 86 p.

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