Northumberland Mine

Site Name

Primary: Northumberland Mine
Secondary: Blue Bell
Secondary: Monitor
Secondary: Last Chance Group
Secondary: Cyprus-Northumberland Mine

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Commodity

Primary: Gold
Primary: Silver
Secondary: Barium-Barite
Tertiary: Iron
Tertiary: Arsenic

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Location

State: Nevada
County: Nye
District: Northumberland District

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Land Status

Land ownership: National Forest
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.
Administrative Organization: Tonopah USFS Administrative District

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Holdings

Not available

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Workings

Not available

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Ownership

Owner Name: Newmont Mining Corporation
Info Year: 2005

Owner Name: NewWest Resources Group's Nevada Western Gold Corporation
Info Year: 2005

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Production

Not available

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Deposit

Record Type: Site
Operation Category: Producer
Deposit Type: vein, disseminated, epithermal
Operation Type: Surface-Underground
Year First Production: 1860
Year Last Production: 1988
Discovery Year: 1866
Years of Production:
Organization:
Significant: Y
Deposit Size: M

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Physiography

Not available

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Mineral Deposit Model

Model Name: Sediment-hosted Au
Model Name: Carbonate-hosted Au-Ag

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Orebody

Form: tabular to irregular

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Structure

Type: R
Description: Major thrust sheets have affected the rocks. A Jurassic granodioritic stock has domed the country rocks.

Type: L
Description: Silicified horizons of the Pogonip group rocks have been extensively fractured and microfractured.

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Alterations

Alteration Type: L
Alteration Text: silicification, sericitization, jasperoid, argillization

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Rocks

Role: Associated
Age Type: Associated Rock Unit
Age in Years: 154.000000+-
Age Young: Late Jurassic

Name: Porphyry
Role: Associated
Description: quartz-eye
Age Type: Associated Rock
Age Young: Tertiary

Name: Quartz Monzonite
Role: Associated
Age Type: Associated Rock
Age Young: Jurassic
Age Old: Cretaceous

Name: Limestone
Role: Host
Age Type: Host Rock
Age Young: Early Devonian
Age Old: Wenlock

Name: Argillite
Role: Host
Age Type: Host Rock
Age Young: Early Devonian
Age Old: Wenlock

Name: Chert
Role: Host
Age Type: Host Rock
Age Young: Ordovician

Name: Quartzite
Role: Host
Age Type: Host Rock
Age Young: Ordovician

Name: Shale
Role: Host
Description: calcareous
Age Type: Host Rock
Age Young: Early Ordovician
Age Old: Late Cambrian

Name: Shale
Role: Host
Description: carbonaceous
Age Type: Host Rock
Age Young: Early Ordovician
Age Old: Late Cambrian

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Analytical Data

Not available

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Materials

Ore: Pyrargyrite
Ore: Cerargyrite
Ore: Arsenopyrite
Ore: Gold
Ore: Scorodite
Ore: Quartz
Ore: Sericite
Ore: Barite

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Comments

Comment (Workings): The mine is developed by a three open pits; with an ore crusher and mill building; all on the site of earlier extensive underground workings consisting of 4000 feet of development at the Blue Bell, and 1600 feet in 3 adits at the Last Chance. Ore was hauled to heap leach pads at the mouth of West Northumberland Canyon in Big Smoky Valley.

Comment (Economic Factors): Northumberland production is reported as 327,000 ounces of gold,produced from 1939-42; 950,000 tons of ore per year mined in the period 1981-84; and 29,667 ounces of gold and 130,394 ounces of silver produced in 1988. The mine was idle from 1989-1993. Reserves in 1988 were reported at 12 million tons grading 0.06 ounces of gold per ton. Other reports estimate a resource of 4 million ounces of gold remaining in the deposit.

Comment (Geology): Disseminated gold mineralization occurs largely in a carbonaceous shale bed near the contact with a granitic intrusive. Ore is present in both upper and lower plate rocks along a thrust fault. Siltstone and limestone have been considerably replaced by jasperoid, which is locally hydrothermally brecciated. Late stage veinlets contain coarse barite crystals.

Comment (Identification): This record covers an area which encompasses the historic Northumberland Mine described by MRDS records # M231715 and W016473 from which all pertinent material has been incorporated into the current record.

Comment (Location): The Northumberland Mine is located on the north slope of Mount Gooding in the Toquima Range near the head of East Northumberland Canyon.

Comment (Development): The silver deposits were discovered in 1866 and the Monitor-Blue Bell ore was treated at a 10-stamp mill at a spring in West Northumberland Canyon, now marked by stone ruins. Sporadic silver mining continued until 1891. Gold was discovered just east of the old silver workings in 1936 and the Northumberland Mining Co was operating from 1939 until 1942 when the gold mine was closed. Gold exploration was resumed in the 1960s by Homestake , Idaho Mining Co., and others in the 1970s resulting in the mining of the low-grade gold deposit in 1981, first by Amoco (later Cyprus Minerals), with mining continuing off and on to the present at the rate of 3000 tpd heap leached ore. Standard Oil Co. spun off Cyprus in 1985. Newmont drilled seven widely spaced holes on the property in 1989 to test targets in Tertiary volcanic tuffs and encountered shallow oxide gold mineralization. In 2003, the NewWest Resources Group's Nevada Western Gold Corporation announced that Newmont Mining Corporation had signed a joint venture agreement for the exploration and development of its Northumberland project. Newmont would be pursuing its exploration program at Northumberland and was embarking on a drilling program in 2004.

Comment (Deposit): There are 3 main veins at the deposit: Lady Cummings, Northumberland, and Detroit veins. Disseminated gold mineralization occurs largely in a carbonaceous shale bed near contact of granitic intrusive. Ore is present in both upper and lower plate rocks along thrust fault. Siltstone and limestone have been considerably replaced by jasperoid, which is locally hydrothermally brecciated. Late-stage veinlets contain coarse barite crystals. Ore is strongly altered, iron-oxide-stained, thin-bedded carbonaceous shale. On the west side of the canyon are highly altered, fractured volcanic rocks. Gold occurs in microfracture fillings of quartz and barite in silicified horizons of the Ordovician Pogonip Group associated with the margins of a monzonite intrusive. Disseminated gold mineralization occurs largely in a carbonaceous shale bed near the contact with a granitic intrusive. Ore is present in both upper and lower plate rocks along a thrust fault. Siltstone and limestone have been considerably replaced by jasperoid, which is locally hydrothermally brecciated. Late stage veinlets contain coarse barite crystals.

Comment (Commodity): Ore Materials: ruby silver, cerargyrite, arsenopyrite, free gold, scorodite

Comment (Commodity): Gangue Materials: quartz, jasperoid,sericite, barite

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References

Reference (Deposit): Kleinhampl, F.J. and Ziony, J.I., 1984, NBMG Bull 99-A and B.

Reference (Deposit): Kral, V. E., 1950, NBMG Bull 50.

Reference (Deposit): Unpublished notes, Nbmg mining district file 42, Item 2.

Reference (Deposit): Nevada Mining Association Newsletter, Oct., 1980.

Reference (Deposit): NBMG, MI-79 thru MI-84, MI-86 thru MI-03

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 Map 91, 1st, 2nd, 3rd.

Reference (Deposit): Amer. Mines (1989), 1989 thru Amer. Mines (2001), 2000

Reference (Deposit): websites - Newmont and NewWest Resources Group.

Reference (Deposit): Motter, J.W. and Chapman, P.E., 1984, AEG Field Trip Guidebook.

Reference (Deposit): Ott, L.E., 1983, Geol. and Mineralization at Northumberland Gold Mine, Nye Co. Nv; MS Thesis; Montana College of Mineral Science and Technology.

Reference (Deposit): NBMG MI-1987

Reference (Deposit): NBMG Mining District File 242, news Clippings.

Reference (Deposit): Field examination of the property, and discussion, L.J. Garside and H.F. Bonham, Jr.,NBMG, May, July, 1981.

Reference (Deposit): Smith, P. and Bentz, J., 1981, NBMG Field Examination.

Reference (Deposit): Tingley, J.V. and Quade, Jack, 1986, NBMG OFR 86-14.

Reference (Deposit): Goldstein, I.J., 1973, Gold Mineralization at the Northumberland Gold Mine, Nye Co., NV; GSA Abstr. Poster session

Reference (Deposit): McKee, E.H., 1974, NBMG Report 19

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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.