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Ontario-Key West-Boss-Gold Flake-Fair Fountain-Bondholder Mine group, Farncomb Hill, French Gulch, Breckenridge Mining District, Summit Co., Colorado, USAi
Regional Level Types
Ontario-Key West-Boss-Gold Flake-Fair Fountain-Bondholder Mine groupGroup of Mines
Farncomb HillHill
French GulchGulch
Breckenridge Mining DistrictMining District
Summit Co.County

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Latitude & Longitude (WGS84):
39° 29' 15'' North , 105° 57' 37'' West
Latitude & Longitude (decimal):
Locality type:
Group of Mines
Köppen climate type:
Nearest Settlements:
Breckenridge4,896 (2017)6.7km
Blue River904 (2017)9.6km
Keystone1,079 (2011)12.6km
Frisco3,035 (2017)15.2km
Copper Mountain385 (2011)15.7km

Former Ag-Zn-Pb-Au occurrences/mine group located in sec. 35, T6S, R77W, 6th PM, on Humbug and Farncomb Hills. MRDS database stated accuracy for this location is 250 meters.

Local rocks include the Cretaceous Pierre Shale.

Workings include underground openings comprised of several adits and shafts (Bondholder Mine: adit; Boss Mine: adit; Fair Mine: adit; Fountain Mine: shaft; Gold Flake Mine: adit; Key West Mine: adit; Ontario Mine: shaft).

Select Mineral List Type

Standard Detailed Strunz Dana Chemical Elements

Commodity List

This is a list of exploitable or exploited mineral commodities recorded at this locality.

Mineral List

2 valid minerals.

Detailed Mineral List:

Formula: CaCO3
Reference: USGS Proffesional Paper 75
Formula: Au
Description: Pseudomorph after sylvanite
Reference: Minerals of Colorado (1997) E.B. Eckel; USGS Proffesional Paper 75; R. P Rothwell (1898) The Mineral Industry, its statistics, technology and trade. Vol. 6 Scientific Publishing Co., New York
Formula: (Fe,O,OH,H2O)
Reference: Minerals of Colorado (1997) E.B. Eckel; R. P Rothwell (1898) The Mineral Industry, its statistics, technology and trade. Vol. 6 Scientific Publishing Co., New York
Reference: Minerals of Colorado (1997) E.B. Eckel

List of minerals arranged by Strunz 10th Edition classification

Group 1 - Elements
Group 5 - Nitrates and Carbonates
Unclassified Minerals, Rocks, etc.

List of minerals arranged by Dana 8th Edition classification

Metals, other than the Platinum Group
Unclassified Minerals, Mixtures, etc.

List of minerals for each chemical element

H Limonite(Fe,O,OH,H2O)
C CalciteCaCO3
O Limonite(Fe,O,OH,H2O)
O CalciteCaCO3
Ca CalciteCaCO3
Fe Limonite(Fe,O,OH,H2O)
Au GoldAu


Sort by

Year (asc) Year (desc) Author (A-Z) Author (Z-A)
Rothwell, R. P. (1898), The Mineral Industry, its statistics, technology and trade. Volume 6, Scientific Publishing Company, New York, NY.
Ransome, F.L. (1911), Geology and Ore Deposits of the Breckenridge District, Colorado, USGS Professional Paper 75, 187 pp.
Raines, E. and Smith, A.E. (1987). "Famous mineral localities: Breckenridge, Colorado." Mineralogical Record, 18(1): 51-61.
Wilson, Anna B. and La Rock, Edward J. (1991), ASCII database for Principal Lode Mines and Mineralized Areas in Southern Summit County, Colorado, USGS Open File Report 91-0027A and B, 22 pp. and one diskette.
Wilson, Anna B. and La Rock, Edward J. (1992), Map showing mineralized areas and principal lode mines in southern Summit County, Colorado, Miscellaneous Field Studies Map 2163, scale 1:50,000
Eckel, Edwin Butt, Robert R. Cobban, Shirley K. Mosburg (1997), Minerals of Colorado, updated & revised., 676 pp., Fulcrum Publishing [ ISBN-10: 1555913652; ISBN-13: 978-1555913656 ].
USGS (2005), Mineral Resources Data System (MRDS): U.S. Geological Survey, Reston, Virginia, deposit ID #10018292.

USGS MRDS Record:10018292

Other Regions, Features and Areas containg this locality

North America
North America PlateTectonic Plate

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