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Eldorado Gold Property

Past Producer in Clark county in Nevada, United States with commodities Gold, Silver, Copper, Lead, Zinc
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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. Alteration
  9. Mineral occurrence model information
  10. Host and associated rocks
  11. Nearby scientific data
  12. Geologic structures
  13. Ore body information
  14. Controls for ore emplacement
  15. Economic information about the deposit and operations
  16. Mining district
  17. Land status
  18. Ownership information
  19. Bibliographic references
  20. General comments
  21. Reporter information

Geologic information

Identification information

Deposit ID 10310510
MRDS ID M031039
Record type Site
Current site name Eldorado Gold Property
Alternate or previous names WBG deposit (Wall Street-Black Hawk-Gracey)
Related records 10037164, 10124552

Comments on the site identification

  • This deposit encompasses some historic mines in the district: Wall Street (MRDS No. M031039), Black Hawk, and Gracey.

Geographic coordinates

Geographic coordinates: -114.84082, 35.71 (WGS84)
Elevation 1030
Relative position The deposit is located on the north side of Eldorado Canyon, about one mile west of the Nelson townsite.

Site location context

Political divisions (FIPS codes)

Clark(county)

Nevada(state)

United States(country)

North America(continent)

Land(continent)

USGS map quadrangles

Nelson(quadrangle 1:24,000 scale)

Boulder City(quadrangle 1:100,000 scale)

Kingman(quadrangle 1:250,000 scale)

Hydrologic units (watersheds)

Havasu-Mohave Lakes(hydrologic unit)

Lower Colorado(hydrologic accounting unit)

Lower Colorado(hydrologic subregion)

Lower Colorado(hydrologic region)

Geographic areas

Country State County
United States Nevada Clark

Public Land Survey System information

Meridian Township Range Section Fraction State
Mount Diablo 026S 064E 04 Nevada

Comments on the location information

  • The deposit is located in the central part of the historic ElDorado (Nelson) District in SE Clark County, about 25 miles south of Boulder City. It encompasses the historic Wall Street and Black Hawk mines and extends east to Gracey Wash.

Commodities

Commodity Importance
Gold Primary
Silver Primary
Copper Secondary
Lead Secondary
Zinc Critical Secondary

Comments on the commodity information

  • Ore Materials: gold
  • Gangue Materials: quartz, calcite, hematite, manganese oxides, clays

Materials information

Materials Type of material
Gold Ore
Quartz Gangue
Calcite Gangue
Hematite Gangue
Clay Gangue

Alteration

  • (Local) Propylitic alteration is widespread throughout the host rocks. Anomalous gold also occurs in zones of local silicification, argillic alteration, and quartz-alunite veining.

Mineral occurrence model information

Model code 129
USGS model code 40a
Deposit model name Detachment-fault-related polymetallic Cu-Au-Ag-Pb-Zn deposits

Host and associated rocks

  • Host or associated Host
    Rock type Plutonic Rock > Granitoid > Monzonite
    Rock unit name Nelson Monzonite
    Stratigraphic age (youngest) Middle Miocene
    Chronological age 14.5
    Dating method K-Ar
  • Host or associated Host
    Rock type Plutonic Rock > Mafic Intrusive Rock
    Stratigraphic age (youngest) Precambrian
  • Host or associated Host
    Rock type Volcanic Rock (Aphanitic) > Intermediate Volcanic Rock > Andesite
    Rock type qualifier tuffs flows and volcaniclastic rocks
    Rock unit name Patsy Mine Volcanics
    Stratigraphic age (youngest) Miocene
  • Host or associated Host
    Rock type Volcanic Rock (Aphanitic) > Felsic Volcanic Rock > Dacite
    Rock type qualifier tuffs flows and volcaniclastic rocks
    Rock unit name Patsy Mine Volcanics
    Stratigraphic age (youngest) Miocene
  • Host or associated Associated
    Rock type Metamorphic Rock > Gneiss
    Rock type qualifier granodioritic
    Stratigraphic age (youngest) Precambrian
  • Host or associated Associated
    Rock type Metamorphic Rock > Schist
    Rock type qualifier granodioritic
    Stratigraphic age (youngest) Precambrian

Nearby scientific data

(1) -114.84082, 35.71
ListMap

Economic information

Geologic structures

Type of structure Regional
Structure description The northern Eldorado Mountains are characterized by many west-dipping listric normal faults which sole into a west-dipping detachment, all formed about between 15 and 10 Ma due to regional extension. The structural style changes markedly in the southern Eldorado Mountains, where Tertiary volcanic strata dip west and are cut by east-dipping listric faults. The Eldorado Canyon and mining district are located between the two structurally distinct areas and represent an ?accommodation zone?.
Type of structure Local
Structure description The deposit is bounded on all sides by post-mineral, high-angle faults.

Ore body information

  • General form subhorizontal lenses

Controls for ore emplacement

  • Ore is associated with shear zones dating from a period of regional extensional faulting about 15-10 Ma.

Comments on the geologic information

  • A thick sequence of Tertiary volcanic rocks overlies Precambrian granodioritic gneiss and schist in the Eldorado district. The Nelson Monzonite, a sill-like stock, intrudes both volcanic and Precambrian rocks.

Economic information about the deposit and operations

Operation type Surface-Underground
Development status Past Producer
Commodity type Metallic
Significant Yes
Discovery year 1857
Year of first production 1863
Year of last production 1970

Mining district

District name Eldorado District
District name Nelson District
District name Colorado District

Land status

Ownership category Private
Ownership category BLM Administrative Area
Area name Las Vegas BLM Administrative District in part

Ownership information

  • Type Owner
    Owner Nelloro Corp.
    Year 1997
  • Type Operator
    Owner Nevada Pacific Mining
    Year 1997

Comments on the workings information

  • The mine area includes old underground workings of the Wall Street Mine area as well as more recent open pits.

Comments on other economic factors

  • 1907-1959 early production was estimated at more than 76 kilotonnes of ore containing 3.16 metric tonnes of Au, and 73.4 metric tonnes of Ag, total value estimated at $2 to $5 million. In 1993, the remaining resource at the deposit was estimated at a minimum of 1140 kilotonnes of ore containing 1.7 tonnes of gold (1.26 million short tons grading 0.043 opt). This resource includes tailings at the Nel property.

Comments on development

  • Gold was first discovered in the area in the 1700s by Spanish explorers who named Eldorado Canyon. Gold was later discovered in 1857 on the Honest Miner claim about 2 miles west of Nelson, after which the district was organized in 1861. Between 1863 and 1907, several mines in the district sporadically produced an unrecorded total amount of gold and silver. Between 1907 and 1954, the mines produced 100,600 ounces of gold and 2,360,000 ounces of silver. A small heap leach operation on the Wall Street claim produced a small amount in the late 1970s, which was the last significant production for the district. Numerous companies have examined the bulk-mineable potential of the district since the 1970s, including Intermountain Exploration, Amselco, Exxon, Weaco, Homestake, Zephyr Resources, and Alta Gold. The combined exploration efforts of these companies resulted in the identification of this laterally-continuous disseminated gold deposit encompassing the historic Wall Street and Black Hawk mines. The deposit was held by Nevada Pacific Mining Company in 1995 and was listed among the properties of Nelloro Corp. in 1997.

Reference information

Bibliographic references

  • Deposit

    Koschmann and Bergendahl, 1968

  • Deposit

    Longwell and others, 1965

  • Deposit

    Robinson, J.P., 1996, in Coyner, A.R., and Fahey, P.L., eds., Geology and ore deposits of the American Cordillera, 1995; symposium proceedings: Reno, Geological Society of Nevada, v. 1, p. 567-579

  • Deposit

    Wyman, R.V., 1987, in Johnson, J. L., ed., Bulk Mineable Precious Metal Deposits of the Western United States, Geological Society of Nevada, p. 109-113.

  • Deposit

    AMH 1997 entry for Nelloro Corp.

  • Deposit

    Long, K.R., DeYoung, J.H., Jr., and Ludington, S.D., 1998, Significant deposits of gold, silver, copper, lead, and zinc in the United States: U.S. Geological Survey Open-File Report 90-206A, 33 p.; 98-206B. one 3.5 inch diskette.

General comments

Subject category Comment text
Deposit Anomalous gold occurs primarily in the Nelson monzonite, a heterogeneous, sill-like stock of Miocene age. Mineralization also occurs in Precambrian mafic crystalline rocks and in a Miocene volcanic sequence of andesitic and dacitic tuffs, flows and volcaniclastic rocks more than 3000 feet thick. The deposit consists of three roughly elliptical, shallow, sub-horizontal pods. Pervasive disseminated gold occurs in flat-lying lenses within host rocks of varying composition and alteration. Mineralization is associated with locally anastomosing shear zones which formed during a period of regional extensional faulting that affected the ElDorado Mountains between 10 and 15 Ma, contemporaneously with the time of mineralization.Propylitic alteration is widespread throughout the host rocks. Gold mineralization is tied to a quartz-calcite-veining event that post-dates the propylitic alteration. Anomalous gold also occurs in zones of local silicification, argillic alteration, and quartz-alunite veining. The WBG mineralized zone trends roughly east-west and is underlain by a seemingly chaoctic distribution of altered volcanic rocks, varied plutonic rocks, and breccia. Structural and lithologic controls on the shape of the WBG deposit are subtle. In the Black Hawk mine area, the Nelson monzonite hosts most mineralization. The host rock is brecciated with strong quartz-calcite veining and pervasive hematite-stained clay alteration. In the Gracey Pit, mineralization is localized along the volcanic/monzonite contact, and to a lesser extent along subhorizontal shears. In the Wall Street Pit area, mineralization is both subhorizontal and along steeply-dipping (50 degrees) faults. The deposit is truncated on all sides by post-mineral, moderate- to steeply dipping faults. Mineralization post-dates the intrusion of the Nelson monzonite, and precedes the bounding faults, bracketing it between 14 and 11 Ma.

Reporter information

Type Date Name Affiliation Comment
Reporter 01-JUN-2003 LaPointe, D.D. Nevada Bureau of Mines and Geology
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.

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