Fourmile Creek District

Site Name

Primary: Fourmile Creek District
Secondary: Fourmile District
Secondary: Timberlake Creek District

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Commodity

Primary: Gold
Secondary: Silver
Tertiary: Thorium
Tertiary: Titanium, Metal
Tertiary: REE
Tertiary: Niobium (Columbium)
Tertiary: Iron

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Location

State: Colorado
County: Moffat
District: Fourmile (Timberlake Creek) District

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Land Status

Land ownership: Federal
Note: the land ownership field only identifies whether the area the mine is in is generally on public lands like Forest Service or BLM land, or if it is in an area that is generally private property. It does not definitively identify property status, nor does it indicate claim status or whether an area is open to prospecting. Always respect private property.

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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

Year: 1912
Description: Ap_Grade: ^0.951 Fine

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Deposit

Record Type: District
Operation Category: Past Producer
Deposit Type: Placer
Operation Type: Unknown
Year First Production: 1892
Year Last Production: 1940
Discovery Year: 1891
Discovery Method: Ore-Mineral In Place
Years of Production:
Organization:
Significant: Y
Deposit Size: S

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Physiography

General Physiographic Area: Rocky Mountain System
Physiographic Province: Wyoming Basin

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Mineral Deposit Model

Model Name: Placer Au-PGE

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Orebody

Not available

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Structure

Type: R
Description: Washakie Basin

Type: L
Description: Washakie Basin

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Alterations

Not available

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Rocks

Name: Trachyte
Role: Associated
Age Type: Associated Rock Unit
Age Young: Pliocene

Name: Trachyte
Role: Associated
Age Type: Associated Rock
Age Young: Pliocene

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Analytical Data

Analytical Data: REPORTED AU VALUES (AT OLD PRICE OF $20.65/OZ) RANGED FROM SEVERAL CENTS TO $1.55 PER CU YD, WITH REPORTS OF SMALL ISOLIATED OCCURRENCES YIELDING UP TO $2.70/YD

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Materials

Ore: Magnetite
Ore: Euxenite
Ore: Ilmenite
Ore: Rutile
Ore: Columbite

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Comments

Comment (Workings): TERRACE, STREAM BED, AND MANTLE PLACERS OPERATED BY GROUND SLUICES, DRYLAND WASHING PLANTS, AND DREDGE. IN HIGHER AREAS, BEDROCK PLACERS IN CONGLOMERATE OPERATED BY UNDERGROUND DRIFT MINING

Comment (Development): ACCORDING TO SNOW (1895), AU WAS FIRST DISCOVERED ON FOURMILE CREEK IN 1891 BY HUGH MORRISON, AN ASPEN PROSPECTOR ON HIS WAY TO UINTA MTNS. MORRISON ALSO PROSPECTED HEADS OF FOUR MILE, WILLOW, AND SLATER CREEKS. SATISFIED WITH AU POTENTIAL, HE AND GEORGE ALBERT RETURNED EARLY NEXT YEAR TO LOCATE CLAIMS ON FOURMILE CREEK, DRY, SCANDINAVIA, AND BIGHOLE GULCHES, AND BEGAN SLUICING OPERATIONS ON FOURMILE CREEK. SHORTLY THEREAFTER, J.G. EDWARDS AND F.A. HINMAN FORMED ROCK SPRINGS PLACER COMPANY AND STARTED OPERATIONS ON 700 ACRES OF MESA LAND ABOVE FOURMILE CREEK. NO APPARENT MINING ACTIVITY SINCE MID 1930S. SINCE 1979, SEVERAL COMPANIES AND INDIVIDUALS HAVE APPLIED FOR MINERAL LEASES ON MANY SECTIONS OF STATE-OWNED MINERAL LAND NEXT TO AND AROUND PAST PRODUCING AREAS. EARLY DREDGES IN FOURMILE AND LAY DISTRICTS OPERATED ON COAL DERIVED BOTH LOCALLY AND FROM WYOMING. MARKS (1915) SUGGESTED THAT LARGER SCALE DIVERSION OF WATER TO DISTRICT FOR PLACER MINING COULD ALSO BE USED TO GENERATE

Comment (Deposit): DISTRICT IS UNDERLAIN BY EOCENE SEDIMENTARY ROCKS DIPPING GENTLY WESTWARD INTO BASIN. QUATERNARY STREAM BED AND TERRACE ALLUVIUM ALONG CREEKS THAT DRAIN IRON SPRINGS DIVIDE. FARNSWORTH'S ORIGINAL DESCRIPTION STATED THAT THE HIGHER PAYING ZONES IN AREA LIE IN SLIGHTLY CONSOLIDATED GRAVELS BENEATH IRON OXIDE-CEMENTED CONGLOMERATE AND ABOVE LAYER OF "BLUE CLAY," (NOW INTERPRETED AS EOCENE BEDROCK). AU CONCENTRATIONS IN TERRACE AND MANTLE DEPOSITS APPEAR LIMITED TO LEVEL BELOW THE PROMINENT CONGLOMERATE OR "CAP ROCK," WHICH WAS INTERPRETED BY PARKER (1974) AND THEOBALD AS A DELTAIC FAN IN EITHER TIPTON TONGUE OF GREEN RIVER FM (EOCENE) OR CATHEDRAL BLUFFS MEMBER OF WASATCH FM (EOCENE). MODERN PLACERS THUS DERIVED FROM EOCENE FOSSIL BEACH AND ALLUVIAL PLACERS AND PROBABLY BEGAN FORMING IN LATE PLIOCENE OR PLEISTOCENE TIME. AGE OF MINERALIZATION CITED FOR PARTICULAR DEPOSIT DEPENDS ON UNIT WORKED--EOCENE FOR BEDROCK OPERATIONS OR QUATERNARY FOR TERRACE, STREAM BED, AND MANTLE OPERATIONS.

Comment (Deposit): IN FOURMILE DISTRICT, 14 RECORDS COMPLETED FOR BLUE GRAVEL CREEK, FARNSWORTH, GOAT, GOOLDY, LAW, ROCK SPRINGS PLACER CO., TIMBERLAKE MINING AND DEVELOPMENT CO., UTAH MINING CO., WEST SIDE MINING ASSOCIATION PROPERTIES AND FOR UNNAMED PLACER PROPERTIES. ; INFO.SRC : 1 PUB LIT; 2 UNPUB REPT

Comment (Development): ELECTRIITY TO OPERATE MINING MACHINERY WITH EXCESS AVAILABLE FOR SALE TO PUBLIC. BECAUSE SMALL POPULATION IN AREA DID NOT WARRANT OUTLAYS FOR SUCH A SYSTEM, MARKS RECOMMENDED COAL AS FUEL. ALTHO MANY SPRINGS ARE FOUND ON IRON SPRINGS DIVIDE AND ALONG MANY CREEKS IN DISTRICT, WATER WAS HISTORICALLY A SERIOUS LIMITATION ON PLACER DEVELOPMENT. EARLY OPERATORS PUMPED WATER FROM SPRINGS AND SHALLOW ARTESIAN WELLS AND DIVERTED WATER THRU DITCHES AND PIPELINES FROM AS FAR AWAY AS LITTLE SNAKE RIVER AND SLATER CREEK. SOME OPERATORS EVEN HAULED PLACER SAND TO SPRINGS FOR SLUICING AND ROCKING. PARKER (1974) BELIEVED THAT MANY WORKABLE PLACERS YET REMAINED BECAUSE OF PAST UNAVAILABILITY OF WATER.

Comment (Production): PRODUCTION FIGURES FOR 1892-1905 UNAVAILABLE. FIGURES FOR 1906-1910 COMBINED WITH ROUTT COUNTY AND NOT REPORTED HERE. OZ AG NOT REPORTED FOR 1928. NO PRODUCTION REPORTED IN DISTRICT FOR 1919, 1921, 1923, 1930, AND AFTER 1940.

Comment (Location): AREA NORTH AND NE OF IRON SPRINGS DIVIDE, INCLUDING DRAINAGES OF TIMBERLAKE CR., HOUSEL GULCH, POLE GULCH, DRY GULCH, SCANDINAVIA GULCH, BIGHOLE GULCH, LOWER FOURMILE CR., PART OF LITTLE SNAKE RIVER. ALSO INCLUDES ALL OR PORTIONS OF T10N, R93W, T11N-R92W, T11N-R93W, T11N-R94W, T12N-R92W, T12N-R93W, T12N-R94W. LAT-LONG GIVEN IS FOR GOOLDY PLACER, LARGEST MINE IN DISTRICT. OTHER QUADRANGLES INCLUDE BIGHOLE BUTTE, EAST TIMBERLAKE CREEK, GREAT DIVIDE, THORNBURGH GULCH. ; INFO FROM LAND.ST :(1974)

Comment (Commodity): NON-GOLD OCCURRENCES REPORTED ONLY FROM FARNSWORTH MINE BUT PROBABLY OCCUR IN OTHER FOSSIL PLACERS IN BEDROCK. AG REPORTED IN GENERAL DISTRICT PRODUCTION AND FROM SEVERAL SPECIFIC OPERATIONS BUT PROBABLY OCCURRED IN MOST.

Comment (Deposit): SOURCEOF AU IN EOCENE FOSSIL PLACERS FIRST THOUGHT TO HAVE BEEN IN ELKHEAD MTNS, BUT INTRUSIVES THERE POSTDATE WASATCH AND GREEN RIVER FORMATIONS AND FOURMILE DISTRICT SEPARATED FROM MTNS BY COMPARATIVELY BARREN FOURMILE AND FORTIFICATION CREEKS. MORE LIKELY SOURCE OF AU IS FROM PARK RANGE ON BASIS OF PEBBLE LITHOLOGIES IN EOCENE CONGLOMERATE. GENETICALLY SIMILAR DEPOSITS AT IRON SPRINGS AND ALONG LAY CREEK ON SOUTH SIDE OF IRON SPRINGS DIVIDE ARE ASSIGNED TO LAY DISTRICT.

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References

Reference (Deposit): PARKER, B.H., JR., 1974, THE PLACERS OF MOFFAT COUNTY, IN GOLD PLACERS OF COLORADO: COLORADO SCHOOL OF MINES QUART., V. 69, NO. 4, P. 150-168.

Reference (Deposit): TWETO, OGDEN, 1976, GEOLOGIC MAP OF THE CRAIG 1X2 QUADRANGLE, NORTHWESTERN COLORADO: USGS MAP I-972

Reference (Deposit): SNOW, E.P., 1895, THE FOURMILE PLACER FIELDS OF (MOFFAT COUNTY), COLORADO AND WYOMING: ENG. MINING JOUR., V. 60, P. 102-105

Reference (Deposit): HOOVER, HERBERT C., 1897, GEOLOGY OF THE FOUR-MILE PLACER MINING DISTRICT (MOFFAT COUNTY), COLORADO: ENG. MINING JOUR., V. 63, P. 510

Reference (Deposit): MARKS, J.H., 1915, PRELIMINARY REPORT, THE TIMBERLAKE OR FOURMILE PLACER DISTRICT, MOFFAT COUNTY: COLORADO STATE PLAN. COMM. UNPUB. REPT., 9 P.

Reference (Deposit): GALE, H.S., 1908, GOLD PLACER DEPOSITS NEAR LAY, ROUTT COUNTY, COLORADO: USGS BULL. 340, P. 84-95.

Reference (Production): 1932-40 FROM VANDERWILT, J.W., 1947, MINERAL RESOURCES OF COLORADO, P. 146; 1911-1931 FROM MINERAL RESOURCES OF THE U.S.

Reference (Deposit): Dunn, L.G., 2003, Colorado Mining Districts--A Reference: Golden, Colo., Colorado School of Mines Library, p. 220-221.

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