Friant District

The Friant District is a gold mine located in Fresno county, California.

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: Friant District

Commodity

Primary: Gold
Secondary: Silver

Location

State: California
County: Fresno
District: Friant District

Land Status

Not available

Holdings

Not available

Workings

Not available

Ownership

Not available

Production

Not available

Deposit

Record Type: District
Operation Category: Producer
Deposit Type: Stream placer
Operation Type: Surface
Discovery Year: 1850
Years of Production:
Organization:
Significant: Y
Deposit Size: S

Physiography

Not available

Mineral Deposit Model

Model Name: Placer Au-PGE

Orebody

Form: Irregular

Structure

Not available

Alterations

Not available

Rocks

Name: Sand and Gravel
Role: Host
Age Type: Host Rock
Age Young: Quaternary

Analytical Data

Not available

Materials

Ore: Gold
Gangue: Quartz

Comments

Comment (Location): Location selected for latitude and longitude is the settlement of Friant on the USGS 7.5-minute Friant quadrangle. This locality is near the historic mining area that is now covered by Millerton Lake.

Comment (Geology): REGIONAL GEOLOGY The Friant District is situated at the westernmost edge of the Sierra Nevada geologic province and within the adjacent Great Valley geologic province, which is here represented by the San Joaquin Valley. The Sierra Nevada province is characterized by complex lithologies and structures that were assembled through various plate-tectonic processes. In this region, the Sierra Nevada province is composed of isolated roof pendants of Paleozoic-Mesozoic metamorphic rocks that are suspended in widespread Mesozoic plutonic rock of the Sierra Nevada Batholith. Together, these rocks compose the basement of the province. This basement is overlain in places by erosional remnants of Cenozoic sedimentary and volcanic rocks, including glacial materials. Structurally, the metamorphic rocks and some of the plutonic rocks of the basement have been deformed by folding and faulting. The basement rocks contain gold in places. The Great Valley province is characterized largely by relatively undeformed Cenozoic sedimentary deposits, which overlie the basement of the Sierra Nevada where it extends westward underneath the San Joaquin Valley. LOCAL GEOLOGY The Friant District is associated with modern alluvial deposits of the main drainage of the San Joaquin River where it discharges into the San Joaquin Valley after passing through the Sierra Nevada basement terranes. The materials in these deposits have been derived by erosion of the various basement and older Cenozoic rocks at higher elevations. In places, the basement rocks contain gold within quartz veins and altered rock. Erosion of the gold-bearing basement rocks provided the gold that was eventually deposited in the modern placer deposits along the San Joaquin River.

Comment (Identification): The district encompasses an approximately 24-mile stretch of the San Joaquin River between Millerton Lake and Herndon.

Comment (Deposit): The gold is present in the river gravels and small terrace deposits adjacent to the San Joaquin River, which receives eroded material from a large drainage basin within the Sierra Nevada to the east.

Comment (Workings): Initially, gold was recovered by standard surface placering methods. Later, placer workings were developed by small-scale dredging and by aggregate-mining techniques.

Comment (Commodity): Commodity Info: the gold is fine and flaky.

Comment (Commodity): Ore Materials: Native gold

Comment (Commodity): Gangue Materials: Metamorphic rocks, igneous rocks, quartz (as clasts)

Comment (Development): Placer mining was conducted originally at a location now inundated by Millerton Lake, which is just upstream from the settlement of Friant. As published information about this district is sparse, it is assumed that this mining activity began during the gold rush, although an exact year is uncertain. At least since the 1940?s, gold has been produced as part of aggregate mining along the San Joaquin River. From 1940-1942, about $200,000 worth of gold was recovered from the sand and gravel excavated near Friant and used in construction of Friant Dam, which impounds Millerton Lake. Gold is still being produced as a by-product of aggregate mining along the San Joaquin River.

Comment (Economic Factors): Tooker and Vercoutere (1986) estimated the production of this region to be about 131,000 ounces through 1981. Clark (1970) estimated that from 1946 to the late 1960?s about $5,000-$25,000 worth of gold was produced annually as a by-product from the aggregate mines along the river.

References

Reference (Deposit): Logan, C.A., Braun, L.T. and Vernon, J.W., 1951, Fresno County: California Journal of Mines and Geology, v. 47, no. 3, p. 503-504.

Reference (Deposit): Matthews, R.A. and Burnett, J.L., 1965, Fresno Sheet: California Division of Mines and Geology, Geologic Map of California, scale 1:250,000.

Reference (Deposit): Clark, W.B., 1970, Gold districts of California: California Division of Mines and Geology Bulletin 193, p. 50.

Reference (Deposit): Tooker, E.W. and Vercoutere, T.L., 1986, Gold in the conterminous United States, Perspective of 1986 - Preliminary map of selected geographic, economic, and geologic attributes of productive (>10,000 oz) gold districts: U.S. Geological Survey Open-File Report 86-209, 32 p.

California Gold

"Where to Find Gold in California" looks at the density of modern placer mining claims along with historical gold mining locations and mining district descriptions to determine areas of high gold discovery potential in California. Read more: Where to Find Gold in California.