Snelling District

The Snelling District is a gold mine located in Merced 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: Snelling District

Commodity

Primary: Gold
Secondary: Silver
Secondary: Platinum

Location

State: California
County: Merced
District: Snelling District

Land Status

Not available

Holdings

Not available

Workings

Not available

Ownership

Not available

Production

Not available

Deposit

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

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
Ore: Platinum
Gangue: Quartz

Comments

Comment (Commodity): Commodity Info: the gold varies from pin-point size to small flakes and averages about 890 in fineness. Platinum and silver are also present. Dredge recoveries ranged from $0.10 to $0.30 of gold per cubic yard with the average close to $0.10.

Comment (Geology): REGIONAL GEOLOGY The Snelling District is situated within the Great Valley geologic province, which is here represented by the San Joaquin Valley. It is adjacent to the westernmost edge of the Sierra Nevada geologic province. The Great Valley province is characterized by Cenozoic sedimentary and volcanic rocks, while 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 belts of Paleozoic-Mesozoic metamorphic complexes that are intruded by various Mesozoic plutons. Together, they compose the basement of the province. This basement is overlain at higher elevations by erosional remnants of Cenozoic volcanic and sedimentary rocks, including gravels. Most of these various lithologies contain gold in places. Structurally, the metamorphic rocks and some of the plutonic rocks have been deformed by folding and faulting. The major fault zones typically trend northerly or northwesterly, although in places intrusion of the younger plutons has deformed some of the zones so as to assume other trends as well. In contrast, the overlying Cenozoic rocks are relatively undeformed. The rocks of the Great Valley province overlie the basement of the Sierra Nevada where it extends westward underneath the San Joaquin Valley. LOCAL GEOLOGY The Snelling District is associated with modern alluvial deposits of the main drainage of the Merced 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 Cenozoic rocks at higher elevations. In places, the basement rocks contain gold within quartz veins and altered rock, while the Cenozoic deposits contain placer gold derived by erosion of these older basement rocks. Erosion of both the gold-bearing basement rocks and the older Cenozoic rocks provided the gold that was eventually deposited in the modern placer deposits along the main Merced River at Snelling.

Comment (Commodity): Ore Materials: Native gold, native platinum

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

Comment (Development): As published information about this district is sparse, it is uncertain exactly what year mining activity began in this district. Nonetheless, some surface placer mining and hydraulicking were done in the terrace deposits along the river during the gold rush. The dominant production from the district came from dredging in the 20th century. This method of mining began in 1907 and continued intermittently at least until 1952. Amalgamation was used in the recovery process.

Comment (Economic Factors): Koschmann and Bergendahl (1968) reported about 516,000 ounces of gold produced from this district. Clark (1970) estimated that total production of gold for this district was approximately $17 million.

Comment (Identification): This district consists of an extensive east-west-trending dredge field along the Merced River between Merced Falls and a location a few miles west of the town of Snelling.

Comment (Location): Location selected for latitude and longitude is the town of Snelling on the USGS 7.5-minute Snelling quadrangle.

Comment (Workings): The district is composed mainly of a dredge field about nine miles long and 1/2 to 1-1/2 miles wide. Minor workings from surface placering and hydraulicking processes were also present locally. Vast deposits of dredge tailings still remain in this district.

Comment (Deposit): Gold was recovered from Quaternary alluvial gravels and flood-plain and terrace deposits in and adjacent to the Merced River. The gravels are loose with very little clay and range from 18 to 36 feet in depth. The gold is distributed throughout the gravel, but the principal concentration is near the bedrock, which has a very irregular surface. Bedrock varies from slate in the vicinity of Merced Falls to Cenozoic volcanic deposits farther west. Platinum is also present in the alluvial deposits.

References

Reference (Deposit): Clark, W. B., 1970, Gold districts of California: California Divisions of Mines and Geology Bulletin 193, p. 120-121.

Reference (Deposit): Davis, F.F. and Carlson, D.W., 1952, Mines and mineral resources of Merced County: California Journal of Mines and Geology, v. 48, no. 3, p. 220-227.

Reference (Deposit): Koschmann, A.H., and Bergendahl, M.H., 1968, Principal gold-producing districts of the United States: U. S. Geological Survey Professional Paper 610, 283 p.

Reference (Deposit): Wagner, D.L., Bortugno, E.J., and McJunkin, R.D., 1990, Geologic map of the San Francisco-San Jose Quadrangle, California: California Department of Conservation, Division of Mines and Geology Regional Geologic Map Series, Map No. 5A, scale 1:250,000.

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.