Sandman Project

Site Name

Primary: Sandman Project

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Commodity

Primary: Gold
Secondary: Silver

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Location

State: Nevada
County: Humboldt
District: Ten Mile 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 BLM District

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Holdings

Not available

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Workings

Not available

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Ownership

Owner Name: Santa Fe Pacific (1990s)
Info Year: 1990

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Production

Not available

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Deposit

Record Type: Site
Operation Category: Producer
Deposit Type: epithermal gold deposit
Operation Type: Surface
Year First Production: 1925
Year Last Production: 1940
Discovery Year: 1900
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: Low-sulfide Au-quartz vein

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Orebody

Form: tabular to iregular

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Structure

Type: L
Description: Bedding plane faults and fractures that crosscut bedding,

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Alterations

Alteration Type: L
Alteration Text: Silicification

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Rocks

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

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

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Analytical Data

Not available

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Materials

Ore: Gold
Ore: Electrum
Ore: Petzite
Gangue: Quartz
Gangue: Adularia

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Comments

Comment (Development): The Ten Mile district was reportedly active from about the early 1900s to the 1940s, with some production judging from the size of the dumps of the old underground workings.No significant production has occurred since then, although several claims are active in the area and in recent years prospectors with metal detectors have reported substantial finds of nuggets and pocket gold around the district.

Comment (Commodity): Ore Materials: gold, electrum, petzite, possibly sulfides

Comment (Commodity): Gangue Materials: quartz, adularia, possibly sulfides

Comment (Deposit): Mineralization occurs in Tertiary tuffaceous and volcaniclastic rocks. Mineralization is comprised of stockworks and veins which are typically open spaced and vuggy grading into wider silicified zones at depth.High-grade gold pockets (typically greater than 30 g/t Au (1 opt Au) were located with a metal detector and appear to be localized along a fault surface. Most of the gold is found along the footwall, where open-space-filling occurred during gold deposition; gold was concentrated in areas where solutions pooled. The presence of some microbreccia and pebble-breccia fragments suggest that the fault was reactivated post-mineralization. Occasionally euhedral gold leaves are found rolled up with and within small breccia fragments, also indicating post gold movement. Mineralization appears to follow bedding plane faults and fractures that crosscut bedding, the largest observed gold-bearing vein strikes N. 55-60E and dips to the 55-65 NW. A second location where gold was found in situ is at the intersection of N-S and NE-SW- trending structures that converge and can be traced to the surface. Evidence exists of supergene enrichment in the upper zones where some exceptionally rich pockets of gold were found concentrated in favorable structural traps. Thus, crystalline native gold is believed to be bi-modal in origin. Primary gold is represented by electrum (600-650 gold fineness) and minor petzite associated with partially oxidized pyrite and secondary alteration products in a gangue of quartz and adularia. The electrum forms crystalline leaves, reticulated dendrites, and rough grains. The second form, believed to be supergene has a much higher fineness and often forms small platelets, wires, and euhedral crystals derived from altered protore and concentrated by residual and supergene processes in the oxidized levels of the mines. The structurally controlled small, bonanza style gold deposits are hosted in Tertiary tuffaceous and volcaniclastic rocks, mostly under pediment gravels and sand.

Comment (Economic Factors): A 1990s Santa Fe report notes reserves of a north reserve area of 327,000 tons grading 0.039 opt Au; a central reserve area of 1 million tons of ore grading 0.081 opt Au (the Southeast Pediment Resource)?; south reserve area of 4 million tons of ore grading 0.028 opt Au; and a northwest area with "highly visible gold". Few records of early production exist but the Ten Mile district mines are believed to have produced approximately 570 kg (20,000 ounces) of gold from about 1900 through 1942. Willden (1964) reports the value of gold and silver from the area in excess of $1 million.

Comment (Environment): The Sandman prospect is located north of Blue Mountain, where several small gold deposits have been defined. (Curt Dechert, personal communication, 1995

Comment (Identification): This prospect is located in the vicinity of the old Badger Mine (MRDS record #D011054) and the Gold Crown claims (MRDS # M242836) from which material has been incorporated into this record.

Comment (Location): The Ten Mile mining district is located between the Krum Hills and Blue Mountain in southeast Humboldt County, Nevada approximately 15 km west of Winnemucca. The Sandman prospect is located north of Blue Mountain. UTMs from "Southeast Pediment Resource" and estimated from small map in company report. Map shows possible resource locations approximately in sections 09, 10, T36N, R36E and approximately in section 23, T37N, R35E.

Comment (Workings): The prospect area is developed by old underground workings in the vicinity of recent surface exploration.

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References

Reference (Deposit): NBMG Map 91, 2nd, 3rd; Santa Fe Company Co. Report 1998? in GSN SP31, 1999

Reference (Deposit): D.A. Davis and J. V. Tingley, 1999, Gold and silver resources in Nevada, NBMG Map 120

Reference (Deposit): Bowell, R.J., Hunerlach, M.P., Parshley, J., and Sears, S., 2000, The Ten Mile mining district, Winnemucca, Nevada: Geology, mineralogy and supergene gold enrichment, in Cluer, J.K., Price, J.G., Struhsacker, E.M., Hardyman, R.F., and Morris, C.L., eds., Geology and ore Deposits 2000: The Great Basin and Beyond: Geological Society of Nevada Symposium Proceedings, Reno/Sparks, May 2000, p. 349-363.

Reference (Deposit): Willden, R., 1964, Geology and mineral deposits of Humboldt County, Nevada: Nevada Bureau of Mines and Geology Bulletin 59, 154 p.

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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.