Fortymile River Placer

Past Producer in Alaska, United States with commodities Gold, Tungsten

Geologic information

Identification information

Deposit ID 10002716
MRDS ID A015161
Record type Site
Current site name Fortymile River Placer
Related records 10185414

Geographic coordinates

Geographic coordinates: -141.18601, 64.26088 (WGS84)
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Geographic areas

Country State
United States Alaska

Comments on the location information

  • USGS MF-393, LOCATIONS 56, 60, 62, 64-69. DEPOSITS ALONG FORTYMILE RIVER FROM CONFLUENCE WITH FRANKLIN CR. TO YUKON BORDER. COORDINATES REPRESENT BONANZA BAR. LAND STATUS VALUE CALCULATED 6-94 USING GIS OVERLAY ANALYSIS WITH BLM 1:2,500,000 SCALE OWNERSHIP STATUS MAP (1991).

Commodities

Commodity Importance
Gold Primary
Tungsten Tertiary

Materials information

Materials Type of material
Gold Ore
Scheelite Ore

Host and associated rocks

  • Host or associated Host
    Rock type Unconsolidated Deposit > Gravel

Nearby scientific data

(1) -141.18601, 64.26088

Comments on the geologic information

  • MAJOR.UNITS: BEDROCK IS MAINLY SCHIST AND INTERBEDDED CRYSTALINE LIMESTONE; GENERALLY STRIKES TRANSVERSE TO RIVER AND DIPS NEARLY VERTICALLY.

Economic information

Economic information about the deposit and operations

Development status Past Producer
Commodity type Metallic
Deposit size Small
Significant No
Discovery year 1886
Year of first production 1887

Mining district

District name Fortymile

Land status

Ownership category State

Comments on development

  • MINING IN MOST YEARS FROM 1887 UNTIL 1960'S OR MORE RECENTLY. MINED MAINLY BY DREDGES. DREDGE FIRST INSTALLED IN 1906. MINED ALSO BY HYDRAULIC PLANTS.

Reference information

Links to other databases

Agency Database name Acronym Record ID Notes
USGS Mineral Resources Data System MRDS A015161

Bibliographic references

  • Deposit

    USGS MF-393, LOCATIONS 56, 60, 62, 64-69

  • Deposit

    USGS BULL. 897-C, P. 185-188

  • Deposit

    USGS BULL. 375, P. 42-44

General comments

Subject category Comment text
Deposit GOLD CONCENTRATED ON BARS DOWNSTREAM FROM GOLD-BEARING TRIBUTARIES, THAT IS, FRANKLIN CREEK, FLAT CREEK, NUGGET CREEK ETC., WHERE CLEAVAGE IS TRANSVERSE TO RIVER COURSE, FORMING NATURAL RIFFLES ON BARS WHERE GOLD IS DEPOSITED. MANY BARS OFTEN REMINED AFTER FLOODING ADDED NEW GOLD. SOME BENCHES NEAR CREEK MOUTHS ARE AURIFEROUS. SOME BARS HAVE VERY LITTLE GRAVEL, WHILE SOME HAVE GRAVEL AS MUCH AS 25 FT. THICK.
Deposit RIVER GRADIENT UNDER 50 FEET PER MILE. LOCATION DESCRIPTION REPRESENTS 9 PLACER DEPOSITS ALONG FORTYMILE RIVER FROM ITS CONFLUENCE WITH FRANKLIN CREEK TO THE YUKON BOARDER. FORTYMILE RIVER MAJOR RIVER DRAINING DISTRICT. ; INFO.SRC : 1 PUB LIT; 2 UNPUB REPT
Deposit THIS SITE NAME WAS CREATED BY THE REPORTER OR OTHER USGS EMPLOYEE BASED ON PROXIMITY TO SOME MAJOR GEOGRAPHIC FEATURE.

Reporter information

Type Date Name Affiliation Comment
Reporter 01-APR-1987 Powers, M.T. (Huber, D.F.) U.S. Geological Survey