Goldfield Main Deposit

Site Name

Primary: Goldfield Main Deposit
Secondary: One of Metallic Ventures? three area properties

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Commodity

Primary: Gold
Secondary: Silver
Secondary: Copper
Secondary: Lead
Tertiary: Tin
Tertiary: Bismuth
Tertiary: Potassium
Tertiary: Antimony

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Location

State: Nevada
County: Esmeralda
District: Goldfield District:

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Land Status

Land ownership: Private
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

Owner Name: Metallic Ventures Inc.
Info Year: 2004

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Production

Not available

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Deposit

Record Type: Site
Operation Category: Producer
Deposit Type: silicified zones at shear intersections
Operation Type: Surface-Underground
Year First Production: 1904
Year Last Production: 1970
Discovery Year: 1902
Years of Production:
Organization:
Significant: Y
Deposit Size: L

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Physiography

Not available

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Mineral Deposit Model

Model Name: Epithermal quartz-alunite Au

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Orebody

Form: Irregular to tabular or knobby

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Structure

Type: L
Description: Historically, ore is localized along the N-S-trending Columbia Mt. Fault, at intersections with left lateral E-W-trending offset faults (800-900 ft offset).

Type: R
Description: Tertiary deposits are domed and faulted by steeply dipping post Miocene: N-S and E-W faults.

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Alterations

Alteration Type: L
Alteration Text: Large envelopes of intense argillic alteration surround most of the ore zones with silicification of core ore zones.

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Rocks

Name: Dacite
Role: Associated
Age Type: Associated Rock
Age Young: Miocene

Name: Andesite
Role: Associated
Age Type: Associated Rock
Age Young: Miocene

Name: Basalt
Role: Associated
Age Type: Associated Rock
Age Young: Pliocene
Age Old: Miocene

Name: Granite
Role: Associated
Age Type: Associated Rock
Age Young: Cretaceous
Age Old: Jurassic

Name: Alkali-Granite (Alaskite)
Role: Associated
Age Type: Associated Rock
Age Young: Cretaceous
Age Old: Jurassic

Name: Sedimentary Rock
Role: Associated
Description: lacustrine
Age Type: Associated Rock
Age Young: Miocene

Name: Limestone
Role: Associated
Age Type: Associated Rock
Age Young: Cambrian

Name: Quartzite
Role: Associated
Age Type: Associated Rock
Age Young: Cambrian

Name: Shale
Role: Associated
Description: siliceous
Age Type: Associated Rock
Age Young: Cambrian

Name: Rhyolite
Role: Host
Age Type: Host Rock
Age Young: Tertiary

Name: Andesite
Role: Host
Age Type: Host Rock
Age Young: Tertiary

Name: Rhyodacite
Role: Host
Description: porphyritic
Age Type: Host Rock
Age Young: Tertiary

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Analytical Data

Not available

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Materials

Ore: Gold
Ore: Pyrite
Ore: Bismuthinite
Ore: Goldfieldite
Ore: Silver
Gangue: Limonite
Gangue: Gypsum
Gangue: Barite
Gangue: Alunite
Gangue: Quartz
Gangue: Kaolin

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Comments

Comment (Development): Gold was discovered in the Goldfield district in December, 1902. High-grade ore was discovered in 1903 immediately northeast of the town of Goldfield. Mining from the claims began in early 1904 and more than 110,000 ounces were produced from 8,000 tons of ore in 1904 Minor production continued from leasing operations through 1926. Between 1927 and 1937, about 3.1 million tons of tailings were reprocessed, yielding about 160,800 ounces of gold. Several mining companies worked and explored the properties during the period 1935-1951, with minor production. Recent activity in the Goldfield district has focused more on exploration and development of heap-leach oxide deposits. Some of the companies that have explored and/or produced gold in the district since the 1970s include Cordex Exploration Company, Noranda Exploration Company, Cyprus Mines Corporation, Newmont, Meridian Precious Metals, Echo Bay Exploration Inc, AMAX Exploration, Inc., Santa Fe Pacific Gold Corporation, Kennecott Exploration Company, Cameco, North Mining Inc., Romarco Minerals Inc., and currently, Metallic Ventures.

Comment (Economic Factors): Historic recorded production from the main Goldfield district is 4,190,133 ounces of gold at an average 0.541 oz/ton gold, including about 160,800 ounces of gold from reworked tailings. 1994 reserves of this area were reported at 3.48 million tons of ore grading 0.071 opt Au, soon to be updated after recent high-grade drilling intercepts.

Comment (Environment): Oxidized subduction-related continental-margin arc along western North America

Comment (Location): The Goldfield Main area is approximately one-half mile east of U.S. Highway 95 and the town of Goldfield, Nevada on a well-maintained gravel road about 28 miles south of Tonopah. The Goldfield Project consists of 385 patented and 849 unpatented claims totalling approximately 18,540 acres located in Esmeralda and Nye Counties, Nevada.

Comment (Workings): Older workings were predominantly underground with later surface workings. The Goldfield Main Area has supported three recent open pit/heap leach operations and if the project goes into production again, there is adequate area for potential tailings storage, waste disposal, and area for processing plants.

Comment (Identification): This new record is for the current Goldfield Main deposit of Metallic Ventures, which is one of three Metallic Ventures properties in the historic Goldfield District: Goldfield Main, McMahon Ridge, and Gemfield, each of which has its own record since they are separate and discrete deposits a few miles apart. The older MRDS record W002900 describes the historic Goldfield District.

Comment (Deposit): Almost all of the precious and base metal production recorded from the Goldfield mining district has come from rich epithermal bonanza ore bodies found in the one-half square mile area directly northeast of the Goldfield town site. These ore bodies occur within silicified hydrothermal alteration zones. Mineralization in the argillized wall rock envelopes appears to be leakage zones emanating from core silicified zones. The drill-defined part of the Goldfield Main mineralized area has the following dimensions: 3,600 ft long, 1,000 ft down dip and open, and averages 100 ft thick. Mineralization at the Main District is structurally controlled in zones about 50-100 feet thick. The major ore host in the Goldfield District is porphyritic rhyodacite. Ore zones are commonly associated with silicification and/or free quartz surrounded by large envelopes of intense argillic alteration. In the main district, gold-copper ores were found in a series of pipe-like shoots referred to locally as ledges, the most productive of which occurred where the east-west striking Goldfield structural trend intersects a mile-long arcuate section of inferred intrusive-related ring-fracture zone. Although the major ore bodies are hosted in a complex intersecting set of faults and fracture zones, the ore-bearing structures are generally north-south trending and sub-parallel to the strike of the ring-fracture zone in that location.

Comment (Geology): The Goldfield mining district is located at the site of a complex and long-lived igneous intrusive and volcanic center that is defined by eruptive vents and curviplanar faults. The local volcanic stratigraphy, a moderately well-defined ring-fracture zone, concentric structural doming, high sulfidation-style quartz-alunite hydrothermal alteration, and widespread copper-gold mineralization are all genetically related to the emplacement of a large dominantly andesitic igneous complex and the most significant components of which are late Oligocene to early Miocene in age.

Comment (Commodity): Ore Materials: native gold, auriferous pyrite, bismuthinite, goldfieldite, rare native silver

Comment (Commodity): Gangue Materials: quartz, alunite, barite, gypsum, limonite, kaolin

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References

Reference (Deposit): Lincoln, F C, 1923, Mining Dist and Min. Res. Nev.: Reno, Nev. Newsletter Pub., p. 67-73

Reference (Deposit): Albers, J.P. and Stewart, J.H., 1972, Geology and Mineral Deposits of Esmeralda County, Nevada: NBMG Bull. 78, p. 67-69

Reference (Deposit): Ransome, F. L. 1909, Geol. and Ore Deposits of Goldfield, Nev.: USGS Prof. Paper 66, 258 p.

Reference (Deposit): Steven Ristorcelli, Scott Hardy, and Neil Prenn, 2003, Geology and Mineralization of the Goldfield Area, Esmeralda,County, Nevada; Geological Society of Nevada Special Publication No. 37: Spring 2003 Field Trip Guidebook Gold Deposits of the Goldfield, Midway and Thunder Mountain Areas

Reference (Deposit): Internet website for Metallic Ventures Inc.

Reference (Deposit): Long, K.R., DeYoung, J.H., Jr., and Ludington, S.D., 1998, Database of significant deposits of gold, silver, copper, lead, and zinc in the United States; Part A, Database description and analysis; part B, Digital database: U.S. Geological Survey Open-File Report 98-206, 33 p., one 3.5 inch diskette.

Reference (Deposit): NBMG MI-80 through MI-99

Reference (Deposit): www.romarco.com

Reference (Deposit): Metallic Ventures Inc., press release, 12/23/02.

Reference (Deposit): Spurr, J E, 1905, The Ores of Goldfield, Nev.: USGS Bull. No. 260, p. 132-139.

Reference (Deposit): Searls, F. Jr., 1948, Geol and Ore Deposits of Goldfield, Nev.: Nevada Univ. Bull., v.42, no. 5, Geology and Mining Ser. 48, 24 p.

Reference (Deposit): Koschmann, A. H. and Bergendahl, M. H., 1968; Principal Gold Producing Districts of the United States: USGS Prof. Paper 610

Reference (Deposit): NBMG Map 91 1st, 2nd, 3rd

Reference (Deposit): MAS, 1984

Reference (Deposit): Amer. Mines (1990-2001)

Reference (Deposit): NBMG Bull 78

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Nevada Gold

Nevada has a total of 368 distinct gold districts. Of the of those, just 36 are major producers with production and/or reserves of over 1,000,000 ounces, 49 have production and/or reserves of over 100,000 ounces, with the rest having less than 100,000 ounces. Read more: Gold Districts of Nevada.