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Cosumnes Mine (Cosumnes Melton; Melton; Middle End), Grizzly Flat, Grizzly Flat Mining District, East Belt, El Dorado Co., California, USAi
Regional Level Types
Cosumnes Mine (Cosumnes Melton; Melton; Middle End)Mine
Grizzly FlatFlat
Grizzly Flat Mining DistrictMining District
East Belt- not defined -
El Dorado Co.County
CaliforniaState
USACountry

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Key
Latitude & Longitude (WGS84):
38° 39' 53'' North , 120° 32' 0'' West
Latitude & Longitude (decimal):
Locality type:
Nearest Settlements:
PlacePopulationDistance
Pollock Pines6,871 (2017)11.7km
Camino1,750 (2011)14.8km
River Pines379 (2011)22.5km
Buckhorn2,429 (2017)23.6km
Placerville10,650 (2017)24.1km


A former lode Cu-Au-Zn-Pb-Ag-Sb occurrence/mine located in secs. 3 & 4, T9N, R13E, MDM, 3.2 km (2.0 miles) N of Grizzly Flat, just S of the Cosumnes River, on private land. Operated by the Caldor Lumber Company. Operated in the 1880's, 1894, 1928 to 1942 & 1942 to 1951. MRDS database stated accuracy for this location is 100 meters. Active during the 1880's and in 1894 as the Melton Mine; reopened in 1928 as the Middle End Mine and operated almost continuously until 1942. Operated by the Cosumnes Mines, Inc. from 1945 to 1950, when purchased by the present owner. The workings are shown in the W½NW¼ sec. 3 on USGS topo map.

Mineralization is a vein deposit hosted in diorite. The ore body strikes NNE and dips W at a thickness of 0.91 meter. Most ore was from the Main or Middle vein that dips steeply at an average of 3 feet thick. Appreciable amounts of galena and pyrite, with sphalerite, chalcopyrite, stibnite and arsenopyrite are present in the ore. Local rocks include Mesozoic gabbroic rocks, unit 2 (undivided).

Workings include underground openings comprised of a 380 foot crosscut adit and several thousand feet of drifts.

Production data are found in: Goodwin, Joseph Grant (1957).

About 10,000 pounds of Pb and some Cu were produced during the period 1928 to 1951, in addition to Au & Ag.

During the last years of production the ore contained up to $25 (period values) Au/ton with sulfide concentrates yielding $100 to $200 (period values) Au/ton.

Select Mineral List Type

Standard Detailed Gallery Strunz Dana Chemical Elements

Mineral List


8 valid minerals.

Detailed Mineral List:

Arsenopyrite
Formula: FeAsS
Reference: USGS (2005), Mineral Resources Data System (MRDS): U.S. Geological Survey, Reston, Virginia, loc. file ID #10101158.
Chalcopyrite
Formula: CuFeS2
Reference: USGS (2005), Mineral Resources Data System (MRDS): U.S. Geological Survey, Reston, Virginia, loc. file ID #10101158.
Galena
Formula: PbS
Reference: USGS (2005), Mineral Resources Data System (MRDS): U.S. Geological Survey, Reston, Virginia, loc. file ID #10101158.
Gold
Formula: Au
Reference: USGS (2005), Mineral Resources Data System (MRDS): U.S. Geological Survey, Reston, Virginia, loc. file ID #10101158.
Pyrite
Formula: FeS2
Reference: USGS (2005), Mineral Resources Data System (MRDS): U.S. Geological Survey, Reston, Virginia, loc. file ID #10101158.
Quartz
Formula: SiO2
Reference: USGS (2005), Mineral Resources Data System (MRDS): U.S. Geological Survey, Reston, Virginia, loc. file ID #10101158.
Sphalerite
Formula: ZnS
Reference: USGS (2005), Mineral Resources Data System (MRDS): U.S. Geological Survey, Reston, Virginia, loc. file ID #10101158.
Stibnite
Formula: Sb2S3
Reference: Clark, Wm. B. & D.W. Carlson (1956), Mines and mineral resources of El Dorado County, California: California Journal of Mines and Geology: 52(4): 413; Pemberton, H. Earl (1983), Minerals of California; Van Nostrand Reinholt Press: 127; ; USGS (2005), Mineral Resources Data System (MRDS): U.S. Geological Survey, Reston, Virginia, loc. file ID #10101158.

Gallery:

List of minerals arranged by Strunz 10th Edition classification

Group 1 - Elements
Gold1.AA.05Au
Group 2 - Sulphides and Sulfosalts
Arsenopyrite2.EB.20FeAsS
Chalcopyrite2.CB.10aCuFeS2
Galena2.CD.10PbS
Pyrite2.EB.05aFeS2
Sphalerite2.CB.05aZnS
Stibnite2.DB.05Sb2S3
Group 4 - Oxides and Hydroxides
Quartz4.DA.05SiO2

List of minerals arranged by Dana 8th Edition classification

Group 1 - NATIVE ELEMENTS AND ALLOYS
Metals, other than the Platinum Group
Gold1.1.1.1Au
Group 2 - SULFIDES
AmXp, with m:p = 1:1
Galena2.8.1.1PbS
Sphalerite2.8.2.1ZnS
AmBnXp, with (m+n):p = 1:1
Chalcopyrite2.9.1.1CuFeS2
AmBnXp, with (m+n):p = 2:3
Stibnite2.11.2.1Sb2S3
AmBnXp, with (m+n):p = 1:2
Arsenopyrite2.12.4.1FeAsS
Pyrite2.12.1.1FeS2
Group 75 - TECTOSILICATES Si Tetrahedral Frameworks
Si Tetrahedral Frameworks - SiO2 with [4] coordinated Si
Quartz75.1.3.1SiO2

List of minerals for each chemical element

OOxygen
O QuartzSiO2
SiSilicon
Si QuartzSiO2
SSulfur
S ChalcopyriteCuFeS2
S StibniteSb2S3
S ArsenopyriteFeAsS
S GalenaPbS
S PyriteFeS2
S SphaleriteZnS
FeIron
Fe ChalcopyriteCuFeS2
Fe ArsenopyriteFeAsS
Fe PyriteFeS2
CuCopper
Cu ChalcopyriteCuFeS2
ZnZinc
Zn SphaleriteZnS
AsArsenic
As ArsenopyriteFeAsS
SbAntimony
Sb StibniteSb2S3
AuGold
Au GoldAu
PbLead
Pb GalenaPbS

References

Sort by

Year (asc) Year (desc) Author (A-Z) Author (Z-A) In-text Citation No.
Logan, Clarence August (1938), Mineral resources of El Dorado County: California Journal of Mines and Geology, California Division Mines (Report 34): 34(3): 265.
USGS quadrangle Sly Park, California, topo map (1953).
Clark, Wm. B. & D.W. Carlson (1956), Mines and mineral resources of El Dorado County, California: California Journal of Mines and Geology: 52(4): 413, 494.
Goodwin, Joseph Grant (1957), Lead and zinc in California. California Journal of Mines and Geology, Division of Mines (Report 53): 53(3&4): 441.
Pemberton, H. Earl (1983), Minerals of California; Van Nostrand Reinholt Press: 82, 127.
USGS (2005), Mineral Resources Data System (MRDS): U.S. Geological Survey, Reston, Virginia, loc. file ID #10030434, 10101158 & 10236224.
U.S. Bureau of Mines, Minerals Availability System (MAS) file #0060171082.

Other Databases

Link to USGS MRDS:10030434

Other Regions, Features and Areas containing this locality

North America PlateTectonic Plate
USA

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