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Last Chance Vein (Granite Mountain Vein), Cornucopia Mine, Cornucopia, Cornucopia Mining District, Baker County, Oregon, USAi
Regional Level Types
Last Chance Vein (Granite Mountain Vein)Vein
Cornucopia MineMine
CornucopiaTown
Cornucopia Mining DistrictMining District
Baker CountyCounty
OregonState
USACountry

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Latitude & Longitude (WGS84):
45° 1' 21'' North , 117° 13' 0'' West
Latitude & Longitude (decimal):
Type:
Nearest Settlements:
PlacePopulationDistance
Halfway291 (2017)17.7km
Richland176 (2017)28.4km
Joseph1,063 (2017)36.9km
Enterprise1,893 (2017)45.1km
Lostine209 (2017)54.3km
Mindat Locality ID:
149904
Long-form identifier:
mindat:1:2:149904:2
GUID (UUID V4):
c99c26a6-17ec-4a8b-ae3a-6a745e370524


A former Pb-Cu-Ag-Au-Zn-Te-As occurrence/mine located in sec. 28, T6S, R45E, WM, 2.5 km (1.5 miles) NW of Cornucopia (site), on National Forest land. Owned by the Forest Industries Insurance Management Company. MRDS database accuracy for this location is not stated.

The Last Chance vein is one of several veins worked by the Cornucopia Mine. Others include the Whitman, Union-Companion, Wallingford and Valley View. Most of the production was from the Union-Companion and Last Chance veins.

Mineralization is hosted in rocks of the Canyon Mountain Complex (granodiorite of the Cornucopia stock, hornblendite, schist and hornfels). The ore body strikes N20E and dips 45W with a width of 2.13 meters and a length of 975.36 meters. Controls for ore emplacement
included pre-Tertiary faults that trend NNE. The deposit involves granodiorite stock and aplite dikes. The vein is mainly quartz with local inclusions of altered host rocks and gouge. The vein crops out at about 7,000 feet of elevation, about 2,500 feet horizontally NW of the Union-Companion vein and about 1½ miles NW of, and 3,000 feet above Cornucopia townsite. Local rocks include intrusive rocks (Cretaceous and Jurassic).

Related tectonic structures: Eugeosyncline.

Workings include underground openings. The vein has been developed and mined to a depth of 2,000 feet below the outcrop.

Select Mineral List Type

Standard Detailed Gallery Strunz Chemical Elements

Mineral List


10 valid minerals.

Gallery:

List of minerals arranged by Strunz 10th Edition classification

Group 1 - Elements
Gold1.AA.05Au
Group 2 - Sulphides and Sulfosalts
Hessite2.BA.60Ag2Te
Stützite2.BA.65Ag5-xTe3, x = 0.24-0.36
Petzite2.BA.75Ag3AuTe2
Coloradoite2.CB.05aHgTe
Sphalerite2.CB.05aZnS
Chalcopyrite2.CB.10aCuFeS2
Galena2.CD.10PbS
Sylvanite2.EA.05AgAuTe4
'Tetrahedrite Subgroup'2.GB.05Cu6(Cu4C2+2)Sb4S12S
Group 4 - Oxides and Hydroxides
Quartz4.DA.05SiO2

List of minerals for each chemical element

OOxygen
O QuartzSiO2
SiSilicon
Si QuartzSiO2
SSulfur
S ChalcopyriteCuFeS2
S GalenaPbS
S SphaleriteZnS
S Tetrahedrite SubgroupCu6(Cu4C22+)Sb4S12S
FeIron
Fe ChalcopyriteCuFeS2
CuCopper
Cu ChalcopyriteCuFeS2
Cu Tetrahedrite SubgroupCu6(Cu4C22+)Sb4S12S
ZnZinc
Zn SphaleriteZnS
AgSilver
Ag HessiteAg2Te
Ag PetziteAg3AuTe2
Ag StütziteAg5-xTe3, x = 0.24-0.36
Ag SylvaniteAgAuTe4
SbAntimony
Sb Tetrahedrite SubgroupCu6(Cu4C22+)Sb4S12S
TeTellurium
Te ColoradoiteHgTe
Te HessiteAg2Te
Te PetziteAg3AuTe2
Te StütziteAg5-xTe3, x = 0.24-0.36
Te SylvaniteAgAuTe4
AuGold
Au GoldAu
Au PetziteAg3AuTe2
Au SylvaniteAgAuTe4
HgMercury
Hg ColoradoiteHgTe
PbLead
Pb GalenaPbS

Other Databases

Link to USGS MRDS:10102961

Other Regions, Features and Areas containing this locality


This page contains all mineral locality references listed on mindat.org. This does not claim to be a complete list. If you know of more minerals from this site, please register so you can add to our database. This locality information is for reference purposes only. You should never attempt to visit any sites listed in mindat.org without first ensuring that you have the permission of the land and/or mineral rights holders for access and that you are aware of all safety precautions necessary.

References

 
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