Cripple Creek District

Site Name

Primary: Cripple Creek District

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Commodity

Primary: Gold
Secondary: Silver
Secondary: Semiprecious Gemstone
Tertiary: Tellurium

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Location

State: Colorado
County: Teller
District: Cripple Creek District

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Land Status

Not available

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Holdings

Not available

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Workings

Not available

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Ownership

Not available

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Production

Not available

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Deposit

Record Type: District
Operation Category: Producer
Operation Type: Unknown
Years of Production:
Organization:
Significant: Y

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Physiography

Not available

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Mineral Deposit Model

Model Name: Alkaline Au-Te (Au-Ag-Te veins)

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Orebody

Not available

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Structure

Type: L
Description: volcanic/diatreme complex

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Alterations

Alteration Type: L
Alteration Text: potassium and carbonate metasomatism

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Rocks

Not available

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Analytical Data

Not available

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Materials

Ore: Calaverite
Ore: Gold
Ore: Sylvanite
Ore: Turquoise
Ore: Krennerite
Gangue: Ankerite
Gangue: Roscoelite
Gangue: Quartz
Gangue: Pyrite
Gangue: Fluorite
Gangue: Dolomite
Gangue: Celestite
Gangue: Calcite
Gangue: Adularia
Trace: Cinnabar
Trace: Sphalerite
Trace: Tetrahedrite
Trace: Stibnite
Trace: Galena

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Comments

Comment (Geology): Two types of gold deposits occur in the district: (1) narrow fissure veins, and sheeted zones of close-spaced veinlets, that carry high-grade gold-silver tellurides in quartz-pyrite-fluorite gangue and persist to vertical depths greater than 3,000 ft., and (2) zones of low-grade disseminated gold-pyrite-adularia hosted in breccia.

Comment (Location): About 24 miles SW of Colorado Springs, the district occupies an elliptical area bounded by Cripple Creek on the NW and by Victor on the south. It covers about 12 square miles in T 15 S, R 69 and 70 W.

Comment (Production): Since its discovery in 1891, the district has produced about 23.5 million oz. of gold through 2005. It is the largest gold district in Colorado, acccounting for about half of the State's cumulative production, and it ranks among the largest in the U.S. Numerous underground mines worked narrow high-grade veins until 1962, when mining virtually ceased because of increasing costs. Renewed activity, beginning about 1975 as gold prices rose, focused on low-grade near-surface deposits. Production at the large open-pit Cresson mine began in 1995, and continues today.

Comment (Reserve-Resource): At 12/31/04, estimated ore reserves were 3,877,815 oz. of gold, at an average grade of 0.029 oz/ton, in 134,299,000 tons of ore. Additional gold resources have been identified that may be converted to reserves later. (Golden Cycle Gold Corp.)

Comment (Commodity): In terms of value, gold is the dominant metal recovered; silver is a minor byproduct, and tellurium is not recovered. Turquoise is produced from a deposit at the northwest edge of the district.

Comment (Development): After discovery of gold in 1891, development of high-grade veins proceeded rapidly, and production increased markedly to nearly 1 million oz./yr by 1900. Production tapered off slowly until World War I, and then fell more thereafter during the 1920s and 1930s. Mining was sharply curtailed during World War II, then rose somewhat in the 1950s when a large, modern mill opened. Rising costs and a constant gold price caused the mill and mines to close at the end of 1961; the district was largely dormant until 1975. New technology and increasing gold prices encouraged exploration and small-scale production of low-grade, near-surface gold deposits. In 1995, production began at the large open-pit Cresson mine and continues at present (2006).

Comment (Workings): More than 500 mines operated in the district; several large mines produced more than 1 million oz. of gold and at least 20 produced more than 150,000 oz. of gold. Several long drainage tunnels were driven deep under the district to alleviate water problems. Shafts were sunk more than 3200 ft deep to tap rich persistent veins.

Comment (Geology): A Tertiary alkaline volcanic/diatreme complex intrudes Precambrian granitic and metamorphic rocks. The volcanic complex is composed mostly of a breccia unit that includes volcanoclastic and lacustrine sediments, and bedded tuffs. The breccia units have been intruded by a series of phonolite dikes and sills primarily along major structural zones. The complex was later intruded by a series of phonolite plugs, flow domes, and small stocks. The last phase of volcanic activity was the development of late-stage breccia pipes and the emplacement of mafic to ultramafic dikes. (Cripple Creek & Victor Gold Mining Co.)

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References

Reference (Deposit): Vardiman, D.M., Roy, E., Thornton, D., Nicholson, D., White, D., and Melker, M., 2006, Geology and exploration developments, Cripple Creek mining district, Colorado, USA: Cripple Creek & Victor Gold Mining Co., Geology Field Guide, 11 p.

Reference (Geology): Thompson, T. B., 1986, Geology and mineral deposits, Cripple Creek district, Colorado, in Cripple Creek mining district: Denver Region Exploration Geologists Society Fall Field Guidebook, pp. 16-63.

Reference (Deposit): Lindgren, W., and Ransome, F. L., 1906, Geology and gold deposits of the Cripple Creek district, Colorado: U.S. Geological Survey Professional Paper 54, 516 p.

Reference (Deposit): Loughlin, G. F., and Koschmann, A. H., 1935, Geology and ore deposits of the Cripple Creek district, Colorado: Colorado Scientific Society Proceedings, v. 13, no. 6, p. 217-435.

Reference (Deposit): Koschmann, A. H., 1949, Structural control of the gold deposits of the Cripple Creek district, Teller County, Colorado: U.S. Geological Survey Bulletin 955-B, p. 19-60.

Reference (Deposit): Koschmann, A. H., and Bergendahl, M. H., 1968, Principal gold-producing districts of the United States: U.S. Geological Survey Professional Paper 610, 283 p.

Reference (Deposit): Sunshine Mining Co. Colorado exploration files, unpublished data, Colorado Geological Survey.

Reference (Deposit): Cripple Creek & Victor Gold Mining Co. corporate info., accessed from internet on 4/13/2006

Reference (Deposit): Jensen, E. P., 2003, Magmatic and hydrothermal evolution of the Cripple Creek gold deposit, Colorado, and comparisons with regional and global magmatic-hydrothermal systems associated with alkaline magmatism: Tucson, AZ, University of Arizona, Ph.D. dissertation, 846 p.

Reference (Reserve-Resource): Golden Cycle Gold Corp. corporate info., accessed from internet on 4/13/2006

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