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Hammonton District

Producer in Yuba county in California, United States with commodities Gold, Platinum, Sand and Gravel, Construction
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Sections on this page
  1. Identification information
  2. Geographic coordinates
  3. Site location context
  4. Geographic areas
  5. Public Land Survey System information
  6. Commodities
  7. Materials information
  8. Mineral occurrence model information
  9. Host and associated rocks
  10. Nearby scientific data
  11. Ore body information
  12. Controls for ore emplacement
  13. Economic information about the deposit and operations
  14. Mining district
  15. Land status
  16. Bibliographic references
  17. General comments
  18. Reporter information

Geologic information

Identification information

Deposit ID 10310626
Record type District
Current site name Hammonton District
Alternate or previous names Yuba Gold Field, Yuba River

Comments on the site identification

  • This district comprises the extensive dredging field in Quaternary sediments along the Yuba River east of Marysville. It extends for approximately eight miles between a point about five miles northeast of Marysville to Long Bar. It is the most productive gold-dredging district in California and for many years was the principal source of gold in the state.

Geographic coordinates

Geographic coordinates: -121.44205, 39.20615 (WGS84)
Location accuracy 100(meters)
Relative position The dredge field begins five miles northeast of the city of Marysville and extends for eight miles upstream to Long Bar.

Site location context

Political divisions (FIPS codes)

Yuba(county)

California(state)

United States(country)

North America(continent)

Land(continent)

USGS map quadrangles

Browns Valley(quadrangle 1:24,000 scale)

Yuba City(quadrangle 1:100,000 scale)

Chico(quadrangle 1:250,000 scale)

Hydrologic units (watersheds)

Lower Sacramento(hydrologic accounting unit)

Sacramento(hydrologic subregion)

California(hydrologic region)

Geographic areas

Country State County
United States California Yuba

Public Land Survey System information

Meridian Township Range Section Fraction State
Mount Diablo 015N 004E 1,2,11,12 California
Mount Diablo 015N 005E 4,5,6 California
Mount Diablo 016N 004E 25,35,36 California
Mount Diablo 016N 005E 22,23,25,26,27,28,29,30,31,32,33,34 California

Comments on the location information

  • Location selected for latitude and longitude is Daguerra Point on the USGS 7.5-minute Browns Valley quadrangle. This feature is not part of the dredge field itself, but represents an approximate center point of the field.

Commodities

Commodity Importance
Gold Primary
Platinum Critical Secondary
Sand and Gravel, Construction Secondary

Comments on the commodity information

  • Commodity Info: Minor amounts of platinum have been recovered from dredging. Sand and gravel for aggregate are produced as a by-product from dredging.
  • Ore Materials: Native gold, native platinum, gravel and sand
  • Gangue Materials: Metamorphic rock, igneous rock, quartz (all as clasts)

Materials information

Materials Type of material
Gold Ore
Platinum Ore
Gravel Ore
Sand Ore
Quartz Gangue

Mineral occurrence model information

Model code 119
USGS model code 39a
Deposit model name Placer Au-PGE
Mark3 model number 54

Host and associated rocks

  • Host or associated Host
    Rock type Unconsolidated Deposit > Sand and Gravel
    Stratigraphic age (youngest) Quaternary

Nearby scientific data

(1) -121.44205, 39.20615
ListMap

Economic information

Ore body information

  • General form Irregular

Controls for ore emplacement

  • Mechanical accumulation within stream-channel lag gravels, bars, and point-bar deposits.

Comments on the geologic information

  • REGIONAL GEOLOGY

    The Hammonton District is situated within both the Sierra Nevada geologic province and the Great Valley geologic province, which is here represented by the Sacramento Valley.

    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 Hammonton District is associated with Cenozoic alluvial deposits of the main drainage of the Yuba River where it discharges into the Sacramento 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 Cenozoic placer deposits along the Yuba River here at Hammonton. Some of these deposits are composed of debris that was washed down from the extensive hydraulic mining farther upstream in the watershed of the Yuba River. Platinum was probably derived from erosion of ultramafic rocks and serpentinite in the Sierra Nevada basement.

Economic information about the deposit and operations

Operation type Surface
Development status Producer
Commodity type Both
Deposit size Large
Significant Yes
Discovery year 1849

Mining district

District name Hammonton District

Land status

Ownership category Private
Area name Yuba County Planning Department
Ownership category BLM Administrative Area
Area name Folsom Field Office

Comments on the workings information

  • Workings from small-scale placer mining were developed during the gold rush. The main workings of the district are those from dredging operations. More than a billion cubic yards of gold-bearing gravels have been dredged in this district. The tailings are present over a length of about eight miles and a width of up to about three miles. They are mostly on the south side of the present channel of the Yuba River.

    Maximum dredging depths ranged from 60-80 feet on the upstream end of the field to 100-125 feet at the downstream end of the field. Dredge No. 21, the most recently active dredge at the field, was capable of digging 140 feet below water level, which made it one of the deepest-digging dredges in the world. It processed about 4 million cubic yards of gravel annually.

    The processes of placer mining, including sections on dredging, are described in Averill (1946).

Comments on other economic factors

  • Koschmann and Bergendahl (1968) reported gold produced from this district through 1959 was about 4,387,000 ounces. Clark (1970) estimated that total production of gold for this district was at least $130 million as of the late 1960?s and 4.8 million ounces as of 1964. As of 1992, more than 5 million ounces of gold had been produced from this district (Cal Sierra Development, Inc., 1992). The recent period of operation was expected to annually produce about 20,000-25,000 ounces of gold per year.

Comments on development

  • The Yuba River in this area was first worked by small-scale surface placering during the gold rush. Bucket-line dredging began in 1903. Dredging continued until 1968 when the last dredge stopped operation because of poor economic conditions. Dredging resumed with Dredge No. 21 in 1981 through a joint venture between Yuba Consolidated Goldfields and Placer Service Corporation. Cal Sierra Developments, Incorporated purchased Dredge No. 21 and all support assets and rights to minerals in 1992. In 2003, Dredge 21, the main dredge operated by Cal Sierra Development, sank out of sight in its 125-foot-deep pond. The cause was unknown at the time. To replace Dredge No. 21, Cal Sierra Development planned to obtain one of its sister dredges, No. 18, which was in Bolivia, South America.

    The Hammonton District is currently the site of controversy concerning public access versus private ownership at the site.

    Many dredges have operated in this district over the last century, and it has been the site of various innovations in the gold-dredging industry. Altogether, at least 21 separate dredges have operated in this field. Most of the district has been dredged at least twice and some areas three or four times, each time to a greater depth with more-efficient equipment for recovery. Natural replenishment of the field by the Yuba River has been curtailed since construction of Englebright Dam on the river in 1941.

    Amalgamation has been used in the recovery process. Also, mercury from the historic hydraulic mines is present in the deposits of this district.

    Vast deposits of dredge tailings still remain in this district. Some of them have been exploited as sources of aggregate, most recently by Western Aggregates, Inc..

Reference information

Bibliographic references

  • Deposit

    Averill, C.V., 1946, Placer mining for gold in California: California Division of Mines Bulletin 135, 377 p.

  • Deposit

    Clark, W. B., 1970, Gold districts of California: California Divisions of Mines and Geology Bulletin 193, p. 62-63.

  • 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.

  • Deposit

    Lindgren, W., 1911, Tertiary gravels of the Sierra Nevada: U.S. Geological Survey Professional Paper 73, p. 221.

  • Deposit

    Logan, C.A., 1919, Platinum and allied metals in California: California State Mining Bureau Bulletin 85, 120 p.

  • Deposit

    O?Brien, J.C., 1952, Mines and mineral resources of Yuba County, California: California Journal of Mines and Geology, v. 48, no. 1, p. 143-179.

  • Deposit

    Saucedo, G.J. and Wagner, D.L., 1992, Geologic map of the Chico Quadrangle, California: California Department of Conservation, Division of Mines and Geology Regional Geologic Map Series, Map No. 7A, scale 1:250,000.

  • Deposit

    Winston, W.B., 1910, Gold dredging in California: California State Mining Bureau Bulletin 57, p. 164-174.

  • Deposit

    Cal Sierra Development, Inc., 1992, Unpublished report on the Yuba Goldfields.

General comments

Subject category Comment text
Deposit The gravel is mostly medium-to-fine in particle size with few large boulders. It rests on metamorphic rock in the eastern part of the district and on clay in the central and western parts.

The high-grade gravel occurs in streaks throughout the deposit. Most of these streaks are in the lower portion of the deposit near bedrock. The highest-grade portion of the deposit was the east, upstream part near the mouth of the Yuba River canyon.From here, the grade decreased and the pay streaks became deeper toward the southwest, or downstream, portion of the field. Little if any ground suitable for dredging is believed to be present west of the current downstream boundary of the field.

Part of the material dredged consists of sediments washed down from the major hydraulic mines that were active in the Sierra Nevada during the mid to late 1800?s. ???????? (19 ) estimated that as much as 45 feet of the upper gravels are composed of this material.

Reporter information

Type Date Name Affiliation Comment
Reporter 10-AUG-2006 Higgins, Chris T. California Geological Survey CGS (Formerly CDMG)
Editor 01-SEP-2007 Schruben, Paul G. U.S. Geological Survey Converted from S&A FileMaker format to Oracle. Edit checks on rocks, units, and ages with Geolex search, and other fields.

Beyond USGS

Supplemental information added by qvyshift.com. Not part of the original USGS MRDS record.

Maps centered on this site

Authoritative California resources

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