Rawhide Mine

Site Name

Primary: Rawhide Mine
Secondary: Denton-Rawhide Mine
Secondary: Kennecott-Rawhide Mine
Secondary: Rawhide Group
Secondary: Rawhide Gold Mine
Secondary: Nevada New Mines
Secondary: Gravel
Secondary: North Buckskin
Secondary: Regent Hill
Secondary: South Forty
Secondary: Black Eagle Southwest
Secondary: Hooligan Hill
Secondary: Murray Hill
Secondary: Balloon Hill
Secondary: Crazy Hill
Secondary: Grutt Hill

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Commodity

Primary: Gold
Primary: Silver
Secondary: Copper
Secondary: Lead
Tertiary: Antimony
Tertiary: Molybdenum
Tertiary: Zinc
Tertiary: Chlorine
Tertiary: Bromine
Tertiary: Aluminum
Tertiary: Tungsten
Tertiary: Selenium
Tertiary: Mercury
Tertiary: Arsenic
Tertiary: Barium-Barite

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Location

State: Nevada
County: Mineral
District: Regent District

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Land Status

Land ownership: BLM Administrative Area
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: Carson City BLM Administrative District

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Holdings

Not available

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Workings

Not available

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Ownership

Owner Name: Pacific Rim Mining Corp.
Percent: 49.00
Info Year: 2004

Owner Name: Kennecott Rawhide Mining Co.
Percent: 51.00
Info Year: 2004

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Production

Not available

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Deposit

Record Type: Site
Operation Category: Producer
Deposit Type: volcanic-hosted epithermal; veins; hydrothermal; shallow hot springs
Operation Type: Surface-Underground
Year First Production: 1907
Year Last Production: 2004
Discovery Year: 1906
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 vein, Comstock

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Orebody

Form: irregular lenses, veins, pod-type ore zones.

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Structure

Type: R
Description: The mine is located in a large caldera system along the northeast margin of the northwest-trending Walker Lane structural zone. The Miocene Rawhide volcanic center is 6.5 by 12km (4 x 7.5 mi.) in area.

Type: L
Description: Three principal structural trends are recognized at Rawhide: 1) north-striking high angle faults, 2) northeast-striking moderate to high angle faults, and 3) an inferred northwest structural trend that is parallel to both the margin of the Rawhide volcanic center and the Walker Lane. North- and northeast -striking moderate to high angle faults are numerous but typically display only minor displacement. Most of the historic gold and silver production has come from veins that occupy these structures, but not all structures are mineralized and many display movement that postdates gold-silver deposition. Displacement on these structures appears to be primarily normal, although oblique-normal displacement is indicated locally by shallowly dipping slickensides. NE-trending structures control the emplacement of late lithic tuff dikes along the SW flanks of Murray and Balloon Hills and the southern flanks of Hooligan Hill. Two major N-S to NNE-trending high angle structures clearly bound and may offset ore grade mineralization at Murray and Crazy hills. Structures with NW trends are rarely exposed but an overall NW trend can be inferred from the alignment of ore zones, the northwesterly strike of tilted structural blocks, the orientation of the Balloon Hill rhyolite and other rhyolite dikes.

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Alterations

Alteration Type: L
Alteration Text: Rocks in the mine area have been affected by silicic, potassic, argillic, and advanced argillic alterations. Silicic alteration is characterized by an increase in quartz or other silica minerals in the host rock; the total silica content of the rock may or may not have increased. Quartz veins commonly accompany silicic alteration, but their presence is not diagnostic of silicic alteration. Rock hardness and resistance to erosion are the primary field criteria for recognizing silicic alteration. Silicic alteration preferentially affects the fine-grained matrix within fragmental host rocks such as the lithic tuff unit and the interstratified siltstone and volcanic breccia unit. More intense silicic alteration is characterized by the replacement of the fine-grained matrix of these rocks by a mosaic of coarser-grained quartz that commonly contains abundant minute rhombs of adularia. Intense silicic alteration results in rock containing only quartz, adularia, and pyrite (or limonite) in significant amounts. Silicic alteration is closely associated with gold ore in the Crazy Hill ore zone. All mineralized rock at rawhide has been potassically altered to some degree, as evidenced by the presence of adularia. The degree of potassic alteration can be adequately assessed only be microscopic identification of adularia and therefore is more difficult to recognize in the field. Three principal habits of adularia are recognized: 1) partial to complete replacement of primary feldspar phenocrysts, 2) overgrowth rims of adularia, and 3) small (typically 0.01-0.1 mm) euhedral rhombs associated with strong silicic alteration. Argillic alteration is characterized by the development of significant quantities of clay minerals (calcite) at the expense of groundmass, mafic minerals, and all phenocrysts except those of adularia and quartz, and apparently has resulted from numerous events including late supergene alteration related to the oxidation of sulfides. The dominant clay minerals formed include illite, kaolinite, and chlorite. Lesser amounts of mixed layer illite-smectites and montmorillonite are present. Argillic alteration is the dominant alteration type at Rawhide and forms a broad halo around more silicified and potassically altered rock, extending well beyond the limits of precious metal mineralization. Argillically altered rock is devoid of precious metal mineralization. The advanced argillic alteration mineral assemblage consists of kaolinite+alunite+quartz, chalcedony or opal. Advanced argillic alteration commonly occurs as irregular bleached zones up to a few inches thick along the margins of paragenetically late veins of kaolinite+alunite+chalcedony. It has only been recognized in oxidized portions of the deposit and may be related to lat

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Rocks

Role: Associated
Age Type: Associated Rock Unit
Age Young: Miocene

Name: Mixed Clastic/Volcanic Rock
Role: Host
Description: volcaniclastic sediments
Age Type: Host Rock
Age Young: Tertiary

Name: Quartz Latite
Role: Host
Age Type: Host Rock
Age Young: Tertiary

Name: Rhyolite
Role: Host
Description: plugs, kaolinized
Age Type: Host Rock
Age Young: Tertiary

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

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Analytical Data

Not available

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Materials

Ore: Pyrargyrite
Ore: Scheelite
Ore: Chrysocolla
Ore: Malachite
Ore: Cerargyrite
Ore: Gold
Ore: Electrum
Ore: Silver
Ore: Embolite
Ore: Galena
Ore: Covellite
Ore: Tetrahedrite
Ore: Argentojarosite
Ore: Acanthite
Ore: Proustite
Ore: Argentite
Ore: Azurite
Ore: Chalcopyrite
Ore: Copper
Gangue: Pyrite
Gangue: Pyrrhotite
Gangue: Hematite
Gangue: Goethite
Gangue: Jarosite
Gangue: Alunite
Gangue: Adularia
Gangue: Calcite
Gangue: Kaolin
Gangue: Chert
Gangue: Quartz
Gangue: Chalcedony

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Comments

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

Comment (Commodity): Gangue Materials: quartz, chalcedony, chert, kaolin, calcite, adularia, alunite, jarosite, goethite, hematite, pyrrhotite, pyrite

Comment (Deposit): Mineralization at Rawhide consists of quartz veins and lodes in kaolinized rhyolite. Ore occurs as disseminated and stockwork ore (veinlets that appear to follow incipient fissures), as well as sporadic ore bodies associated with abundant breccia, phreatomagmatic and phreatic, with strong silicification bordered by argillic zones. The environment of deposition was a shallow hot spring with abundant hydrofracturing. An oxidized zone up to a few hundred feet deep in vent areas is underlain by a sulfide zone. The chief ore minerals in the oxidized zone are cerargyrite, pyrite, native silver, native gold, and electrum. Ore minerals in the sulfide zones are argentite, proustite, pyargyrite, pyrite, gold and electrum. The gangue minerals resulting from hydrothermal replacement are adularia, jarosite, kaolin, pyrite, pyrrhotite, quartz, and calcite. Some gold and silver were recovered by dry wash placer method south and southwest of Rawhide. The main belt of mineralization occurs along Balloon, Murray, and Grutt Hills. Within this zone, bodies of good grade milling ore are 5 to 30 feet wide. Sporadic ore bodies are associated with brecciation of the rock. Particularly in the Grutt and Murray Hill areas, many of the veins trend north to NE. All except 2 of the veins dip steeply west. Bulk mineable ore occurs primarily in intensely fractured andesite along the hanging wall of the rhyolite intrusion and is characterized by abundant, closely spaced, sheeted to stockwork quartz-adularia veins. Ore also occurs in zones of primary permeability in porous lithic tuffs and volcaniclastic sediments, where it is finely disseminated and is accompanied by pervasive silicification and adularization with minor or no associated veins. Several separate pod-like ore zones occur within a NW-trending area 2440 m long and 400 m wide. Individual ore zones are irregular in geometry but typically are elongate to the NW with local NE-trending apophyses. Mineralized veins strike north to NE, an orientation transverse to the overall trend of the orebodies. Gold occurs as electrum in both oxide and sulfide ores; the electrum is dominantly gold in oxide ore but contains significant silver in sulfide ore. In oxide ore, silver occurs primarily as embolite and lesser cerargyrite. In sulfide ore, silver occurs as the selenides, sulfides and sulfosalts listed above. Silver:gold averages 10:1 in both oxide and sulfide zones and generally increases as au grade decreases with distance from ore. Silver:gold ratios as high as 400:1 are known along the base of oxidation and in strongly argillized zones.

Comment (Workings): The mine is an open pit and heap-leach operation, currently (2005) in the closure and reclamation phase. Extensive older workings were mainly underground consisting of a number of shafts and tunnels. There were 17 miles of workings at Nevada New Mines alone. Four known bulk mineable ore zones are aligned on a N40W trend: Grutt Hill, Balloon Hill, Murray Hill, and Crazy Hill. These deposits will be mined from two pits. The Crazy Hill ore zone was mined from the Crazy Hill pit at the southern end of the deposit. The Murray Hill pit was a larger, NW-trending, elongate pit that developed the series of ore zones that underlay Murray, Balloon, and Grutt hills. The two pits were separated by a low septum of waste rock. Mineralization at Hooligan Hill merged with that in the Murray Hill pit.

Comment (Geology): The Rawhide District is structurally complex and contains NW, NE, and N-S trending fault sets that all show pre-, syn-, and post- ore deposition movement. Formations in area are rhyolite, dacite, and andesite. Mineralization is mainly in kaolinized rhyolite. Placer deposits overlie the rhyolite in the valleys east and west of Balloon and Murray Hills and continue for 5.5 miles down wash to Alkali Flat. The Crazy Hill deposit is hosted in tuffaceous epiclastic sedimentary, and igneous volcanic rocks that are intruded by a post mineralization rhyolite plug. Alunite is said to occur in thin veins associated with gold ores in altered volcanic rocks. Volcanic rocks consist of vent breccia, flows, plugs, and pyroclastics of Tertiary age, approx. 15.5 Ma, K-Ar ages.

Comment (Identification): This record incorporates all material from earlier record #W016386.

Comment (Location): The Rawhide Mine is located in Mineral County, approximately 58 miles by road southeast of the city of Fallon. The current open pit mine occupies the same general area of the historic Rawhide mining district. UTM is to the middle of the Balloon Hill-Murray Hill pit area

Comment (Commodity): Ore Materials: native gold, electrum, native silver, embolite, cerargyrite, pyrargyrite, argentite, acanthite, argentojarosite, tetrahedrite, proustite, azurite, chalcopyrite, native copper, covellite, galena, scheelite, chrysocolla, malachite

Comment (Development): The Rawhide mining district was staked on Christmas Day in 1906 and the first gold deposits were discovered on March 1, 1907. Most of the 50,000 ounces of gold and 750,000 ounces of silver that were produced in the Regent District during the period 1907-1920 came from Rawhide, from leasing operations. George Graham Rice promoted the Rawhide Queen Mining Co., the Rawhide Coalition Mining Co., and the Black Eagle Mining and Milling Co. In 1912 the Nevada New Mines Company was incorporated and took over the George Graham Rice promotions. During its peak, the town of Rawhide had a population of 10,000. The town's population dropped to 500 by 1910, with the final resident leaving in 1966. Mining in the district has been essentially inactive since minor placer operations were conducted in the 1930s. Over the past several decades numerous mining companies have investigated the potential for bulk-mineable precious metals ore at Rawhide. The most notable effort occurred from 1969 to 1971, when a Homestake-Getty joint venture drilled 58 holes that partially delineated the ore zones of later interest. In 1982 a kennecott subsidiary began work on the property. A joint venture between Plexus, Kiewit and Kennecott worked on the property from 1982-1985 drilling numerous holes and making metallurgical tests. Mine construction was initiated in August 1989 and production averaging approximately 100,000 ounces of gold and 1 million ounces of silver annually began in April 1990, beginning with the Crazy Hill deposit. This deposit was mined out by about 1991. Mining of the Murray Hill deposit was next in line and the Murray pit was still active in 2002. The mine is now (2004-2005) in the process of final reclamation and closure. Mining from the open pits was discontinued in October 2002 as all economically recoverable ore was depleted. Processing (crushing and stacking) of low-grade stockpile ore continued through mid- 2003. Leaching of ore and solution recirculation will continue for an estimated three years during which fresh water additions will be discontinued to reduce the total volume of solution in the spent ore heaps. The remaining solution will be treated through a carbon plant and either evaporated or land applied. An expert closure panel met in December 2002 to review a draft reclamation and closure plan that was submitted to the Bureau of Land Management and the Nevada Department of Environmental Protection in 2003. Final reclamation and closure is scheduled for 2006. Recontouring of the spent ore heaps should begin at the end of 2005, with final reclamation following initial pad drain down occurring over a period of two years. During this time, remaining portions of the waste rock storage areas, roads and unnecessary facilities will be reclaimed and/or removed.

Comment (Economic Factors): In 1986, reserves for the Kennecott-Rawhide mine were reported as 24.1 million tons of ore grading 0.045 opt gold and 0.47 opt silver. In 1989, reserves for the Kennecott-Rawhide mine were reported as 29.4 million tons of ore grading 0.040 opt gold and 0.368 opt silver with a geologic resource of 59.3 million tons grading 0.0274 opt gold and 0.298 opt silver. In 1997 reserves were reported as 447,000 ounces of gold and 3.9 million ounces of silver. From 1907-1920, the mines in the district produced 50,000 ounces of gold and 750,000 ounces of silver. Total production from the Kennecott-Rawhide mine from 1990 through 2003 has been 1,383,663 ounces of gold and 10,868,939 ounces of silver, distributed as follows for these years: 1990-98: 916,800 oz Au, 7,438,000 oz Ag 1999: 115,900 oz Au, 665,000 oz Ag 2000: 104,349 oz Au, 817,787 oz Ag 2001: 100,747 oz Au, 727,095 oz Ag 2002: 82,584 oz Au, 695,248 oz Ag 2003: 63,283 oz Au, 525,809 oz Ag

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References

Reference (Deposit): Mining Journal/ Montagu Mining Finance, Minindatabase, 8/10/91.

Reference (Deposit): NBMG, 1994, MI-1993

Reference (Deposit): Lincoln, F.C., 1923, Mining Districts and Mineral Resources of Nevada; Nevada Newsletter Publishing Co.

Reference (Deposit): Mining and Scientific Press, Notes on Rawhide, Nevada; March 28, 1908

Reference (Deposit): Bates, James A., Nov. 1967, unpublished report on the Rawhide Lode-Placer Deposits in Mineral County, Nevada.

Reference (Deposit): Archibald, N.L., 1966, Industrial Mineral Deposits of Mineral County, Nevada: NBMG Report 14. p 30.

Reference (Deposit): Bonham, H.F. 1988, NBMG MI-1987

Reference (Deposit): Bonham, H.F. 1986, NBMG Map 91

Reference (Deposit): Bonham, H.F., 1986 NBMG Field Examination and Sample Analysis

Reference (Deposit): NBMG Mining District File #206, numerous press clippings 1986-1987.

Reference (Deposit): Plexus Resource Corp. 1986, Rawhide Gold Mine Report.

Reference (Deposit): Black, John E., 1988, Mineralization and Wallrock Alteration at the Rawhide Gold-Silver Deposit Mineral Co., Master's Thesis, Stanford University.

Reference (Deposit): Black, John E., et al., 1991, Geology and Mineralization at the Rawhide Au-Ag Deposit, Mineral County, NV in Raines, G.L., et al., Eds., Geology and Ore Deposits of the Great Basin, The Geological Society of Nevada, Reno, p. 1123-1144.

Reference (Deposit): Ross, D.C., 1961, Geology and Mineral Deposits of Mineral County, Nevada; NBMG Bull. 58. pp. 83-84.

Reference (Deposit): Vanderburg, 1937, Reconnaissance of Mining Districts in Mineral County, Nevada; USBM IC 6941. pp. 58-64.

Reference (Deposit): NBMG, 1991, The Nevada Mineral Industry-1990, NBMG Special Publication MI-1990, p.16 and 23.

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): Nevada Division of Minerals, 1994

Reference (Deposit): The Mining Record April 28,1993

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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.