Relief Canyon Gold Project

Site Name

Primary: Relief Canyon Gold Project
Secondary: Relief Canyon Gold Mine
Secondary: Bohannan Fluorite Prospect

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Commodity

Primary: Gold
Primary: Silver
Secondary: Fluorine-Fluorite
Tertiary: Thallium
Tertiary: Arsenic
Tertiary: Antimony
Tertiary: Mercury

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Location

State: Nevada
County: Pershing
District: Antelope Springs 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: Winnemucca BLMDistrict

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Holdings

Not available

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Workings

Not available

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Ownership

Owner Name: Newmont
Info Year: 2004

Owner Name: New Gold, Inc.
Info Year: 2004

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Production

Not available

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Deposit

Record Type: Site
Operation Category: Past Producer
Deposit Type: hydrothermal breccia-filling, hydrothermal solution-cavity
Operation Type: Surface-Underground
Year First Production: 1984
Year Last Production: 1990
Discovery Year: 1979
Years of Production:
Organization:
Significant: Y
Deposit Size: S

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Physiography

Not available

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Mineral Deposit Model

Model Name: Sediment-hosted Au

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Orebody

Form: disseminated, stratabound and strata-conformable mineralization.

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Structure

Type: R
Description: Relief Canyon Thrust. The mine area lies within a northeast-trending structural belt parallel to and 140 km west of the Battle Mountain Trend. The belt is about 65 km long and averages 8.3 km in width.

Type: L
Description: Range front faults terminate ore to the west (Black Ridge Fault). The dip of the brecciated contact (Relief Canyon Thrust? ) between the Natchez Pass and Grass Valley Formations varies and has the appearance of a NE-SW striking anticline that plunges to the SW. A small fold perpendicular to the plane of this anticline forms a dome over the southerly portion of the deposit.

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Alterations

Alteration Type: L
Alteration Text: Two obvious alteration features present at surface include large resistant outcrops of jasperoid and widespread iron oxide staining. In the jasperoid breccia with clay seams, gold mineralization is related to both silicification and argillization. In the mixed breccia and limestone breccia, gold mineralization is associated with argillic alteration. A detailed comparison of alteration with gold grade from drill data indicates that the highest gold values are often associated with argillic alteration rather than silicification. At surface, diorite intrusives are both extensively oxidized and propylitized.

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Rocks

Name: Diorite
Role: Associated
Description: dikes
Age Type: Associated Rock
Age Young: Cretaceous
Age Old: Jurassic

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

Name: Limestone
Role: Host
Age Type: Host Rock
Age Young: Late Triassic

Name: Limestone
Role: Host
Description: breccia and fresh
Age Type: Host Rock
Age Young: Late Triassic
Age Old: Middle Triassic

Name: Shale
Role: Host
Description: breccia
Age Type: Host Rock
Age Young: Late Triassic

Name: Sedimentary Breccia
Role: Host
Description: shale and limestone
Age Type: Host Rock
Age Young: Late Triassic
Age Old: Middle Triassic

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Analytical Data

Not available

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Materials

Ore: Gold
Ore: Silver
Ore: Electrum
Gangue: Hematite
Gangue: Talc
Gangue: Serpentine
Gangue: Calcite
Gangue: Fluorite
Gangue: Quartz
Gangue: Pyrite

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Comments

Comment (Commodity): Ore Materials: native gold, native silver, electrum

Comment (Commodity): Gangue Materials: quartz, fluorite, calcite, serpentine, talc, hematite, pyrite

Comment (Location): The property consists of fee lands and unpatented mining claims at the south end of the West Humboldt Range. The deposit is located south of Couer?s Rochester and Nevada Packard deposits and north of the Antelope Springs mercury deposits

Comment (Workings): Workings related to historic fluorite prospecting consisted of 105 ft. of underground development, small open cuts, and pits. The modern gold mine consisted of an open pit with 15 ft high benches, leach pads, and a gold recovery plant.

Comment (Geology): Historic fluorite prospecting focused on minor amounts of disseminated fluorspar in shale and limestone of the Natchez Pass Formation. Gold mineralization at Relief Canyon occurs along the highly brecciated contact between the Natchez Pass Formation and the overlying Grass Valley Formation. The nature of this breccia is equivocal. Early workers concluded that it is a thrust fault breccia, but later workers concluded that it is a solution collapse breccia. Au values typically are highest immediately below the Grass Valley Formation at the contact with the breccia units and decrease toward the base of the breccia units. Several types of gold mineralization have been recognized at Relief Canyon. A large amount of ore is present as a jasperoid breccia. However, significant amounts of ore occur as a mixed breccia composed of Grass Valley and Natchez Pass formations, clay, and jasperoid breccia. Gold also occurs in clay, a condition which plagued Lacana's efforts to heap leach the ore. Below masses of jasperoid, jasperoid stringers containing gold extend into fresh limestone of the Natchez Pass Formation. Irregular zones of mineralization are also present in minable quantities in the Cane Spring Formation. A diorite dike terminates ore to the east. A significant portion of the Relief Canyon deposit was covered by Quaternary alluvium.

Comment (Identification): The currently described gold exporation project encompasses the existing Relief Canyon Mine deposit ias well as surroundinjg area. All material from the earlier Relief Canyon Mine MRDS record M242418 and the inactive Bohannan Fluorite prospect MRDS record M060411, has been incorporated into the current record as well as additional material on the more recent prospect area.

Comment (Development): In 1978, Falconi and Associates located claims on 2000 acres over the long inactive Bohannon fluorite prospect. In 1979, Duval Corp initiated a precious metals exploration program and discovered gold on the Falconi ground. During 1981-1982, Duval got an option from Falconi and staked an additional 2300 acres. Widely spaced drilling indicated low grade gold mineralization. In October, 1982, Lacana optioned the property from Duval and determined potential for an economic heap-leachable gold deposit. In 1983 Lacana proved up the deposit with a 50,000-ft drilling program and completed bulk head leach tests on two 4300-ton samples. Economic feasibility studies were initiated in 1983 and were approved in April 1984, with calculated reserves sufficient for an 8 year mine life at a production rate of 24,500 ounces of gold per year. Construction of the gold recovery plant and leach facilities immediately followed. In Sept 1984,the first 100,000 ton ore heap commenced. A total of about 400,000 tons of ore was processed in 1984. The first bullion was poured in Oct 1984. Lacana suspended operations in late 1985 because of poor gold recovery rates (45%) in leaching run of mine material. Pegasus acquired the property in 1986. After adding crushing and agglomerating facilities, Pegasus put the deposit back into production in November 1986 and realized gold recovery rates on the order of 65%. Pegasus concluded mining operations in August, 1989, although leaching of ore already on the pads continued until August, 1990.Lacana employed 23 persons at Relief Canyon in 1983. Pegasus employed 30 persons at Relief Canyon in 1988; Morrison-Knudsen was the mining contractor, employing an additional 33 persons at Relief Canyon that year. Cash cost of production per ounce of gold was $283 in 1987, $315 in 1989, and $438 in 1990. Strip ratio was 1.53:1 in 1989. In 1989, gold recovery was 62% and silver recovery was 50%. Relief Canyon returned $13.6 million in cash flow on an initial investment of $2.7 million for Pegasus Gold Corp. The property was acquired in 1993 by J. D. Welsh & Associates, Inc. after completing detoxification requirements on the heap-leach pad for Pegasus. The property is on a standby basis and being reclaimed. New Gold currently (2004) holds claims covering the pits and leach pads and has estimated a remaining resource of some 11.6 Mt @ 0.037 opt Au, 35% of which is on Newmont land. Potential exists to increase the resource and discover new disseminated gold and silver resources under alluvial cover in Packard Flat. In 2006, Victoria Resource Corporation (a 31% owned affiliate of Bema Gold Corporation) signed with Newmont Mining Corp. to lease the Relief Canyon Project encompassing 10 full and partial sections of private checkerboard acreage and 155 unpatented claims surrounding the Relief Canyon mine. The area was explored for Carlin Type mineralization exploration from 1984-1992 with drilling limited to the area of the mine and some of the nearby mercury and antimony operations. Reconnaissance mapping by Victoria indicates zones of gold potential where structural systems intersect and suggests both underground and open-pit potential.

Comment (Economic Factors): The Relief Canyon deposit was mined by Lacana and Pegasus who produced a total of 430,000 ounces of gold from 10.5 million tons of ore grading 0.037 opt gold between 1985 and 1989. Production in 1984 and from 1987-1990 was 140,766 oz Au and 39,235 oz Ag. 1996 reported reserves were 8.6 Million tons of ore grading 0.022 opt Au. Drill-indicated reserves (2003) were reported as 2.0 million tons at 0.033 opt gold. Newgold currently (2004) estimate a remaining resource of some 11.6 Million tons of ore grading 0.037 opt Au, not including possible resources on adjacent Packard Flat. Production in 1984 and from 1987-9 was 140,766 oz Au; 1989-90: 39,235 oz Ag. Total production from 1985 to 1989 is reported to be 430,000 ounces of gold at an average grade of 1.27 grams per tonne .

Comment (Deposit): Relief Canyon is a classic sediment-hosted gold deposit forming along the brecciated unconformity at the contact between the Triassic Grass Valley Shale and Natchez Pass Limestone at the intersection of the Relief Canyon Thrust and Black Ridge Fault. Shale, siltstone, and quartzite of the Late Triassic Grass Valley Formation have been thrust over dolomitic limestones of the Late Triassic Natchez Pass Formation. Gold mineralization occurs in a jasperoid and solution breccia that occupies the thrust-fault contact. Gold is associated with argillic alteration and silicification, and with anomalous silver, arsenic, antimony, and fluorine Gold occurs as 2-4 micron-sized flakes of native gold and rarely as electrum in the jasperoids, carbon-rich zones, breccia matrix, or with amorphous hematite. Gold mineralization is associated with Carlin-style jasperoids and zones of brecciation in sulfidized limestone.

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References

Reference (Deposit): Bonham, H.F., Jr, and Hess, R. H., 1992, Bulk-Mineable Precious-Metal Deposits, in The Nevada Mineral Industry 1991, Nevada Bureau Of Mines and Geology, Special Pub., MI-1991, p24

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

Reference (Deposit): Pegasus Gold, Inc., Annual Reports for 1986, 1987, 1989, 1990.

Reference (Deposit): Southern Pacific Co., 1964, Minerals For Industry-Northern Nevada and Northwestern Utah, Summary of Geological Survey of 1955-1961, v. 1: San Francisco, Southern Pacific Co, P. 45.

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): Crafford, A.E.J. (ed.), 2003, GSN Road Log 44, Coal Canyon Road East from I80 Exit 112.

Reference (Deposit): Johnson, M. G., 1977, Geology and Mineral Deposits of Pershing County, Nevada, NBMG Bull. 89.

Reference (Deposit): Fiannaca, M. and McKee, J., 1983, Geology and Development of the Relief Canyon Gold Deposit, Pershing Co., NV; paper presented at the 89th Annual Northwest Mining Convention, Spokane, WA, 1983

Reference (Deposit): Geological Society of Nevada 1984 meeting and field trip road log, Sept. 1984.

Reference (Deposit): Division of Mine Inspection, Dec. 1983, Directory of Nevada Mining Operations, active During Calendar Year 1983.

Reference (Deposit): NBMG Map 84, 1983, Active Mines and Oil Fields

Reference (Deposit): Lacana Gold Inc.'s brochure on Relief Canyon Mine's official opening, Oct, 1984.

Reference (Deposit): Wittkop, R. W., Parratt, R. L., Bruce, W. R., 1984, Geology and Mineralization at the Relief Canyon Gold Deposit, Pershing County, Nevada, Preprint No. 84-100, Society of Mining Engineers of AIME, Littleton, Co, 5 pp.

Reference (Deposit): Pegasus Gold, 1988, Relief Canyon Mine circular (unpublished visitor's fact sheet).

Reference (Deposit): Wallace and Tatlock, 1962, Suggestions for prospecng in the Humboldt Range and adjacent areas, Nevada, USGS PP 450-B3-B5.

Reference (Deposit): Wallace,. E., Silberling, N. J., Irwin, W. P., And Tatlock, D. B., 1969, Geologic Map of the Buffalo Mountain Quadrangle, Pershing and Churchill Counties, Nevada, USGS Map GQ-821.

Reference (Deposit): Tingley, J. V., Nevada Bureau of Mines and Geology, Computerized Geochemistry Database.

Reference (Deposit): Horton, R.C., 1961, An Inventory of Fluorspar Occurrences in Nevada, NBMG Rept. 1.

Reference (Deposit): Engineering and Mining Journal, June 1988, p. 45-46

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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.