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Gold King Mine (Gold King Extension), Gladstone, Eureka District, San Juan Co., Colorado, USAi
Regional Level Types
Gold King Mine (Gold King Extension)Mine
Gladstone- not defined -
Eureka DistrictMining District
San Juan Co.County

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Lock Map
View of the Gladstone gold mining area, ca. 1904.

Gold King Mine, Gladstone, Eureka District, San Juan Co., Colorado, USA
View of the Gladstone gold mining area, ca. 1904.

Gold King Mine, Gladstone, Eureka District, San Juan Co., Colorado, USA
View of the Gladstone gold mining area, ca. 1904.

Gold King Mine, Gladstone, Eureka District, San Juan Co., Colorado, USA
Latitude & Longitude (WGS84): 37° 53' 42'' North , 107° 38' 19'' West
Latitude & Longitude (decimal): 37.89500,-107.63861
GeoHash:G#: 9werwdefq
Locality type:Mine
Köppen climate type:Dfc : Subarctic climate
Nearest Settlements:
Silverton637 (2011)9.5km
Ouray1,008 (2017)14.5km
Telluride2,399 (2018)15.9km
Ophir169 (2017)17.5km
Mountain Village1,395 (2017)19.5km

Ref.: Rocks & Min.:63:366; Burbank(1951). A gold mine featuring the American tunnel (lower level).

The Gold King Mine was one of the larger producers in the Gladstone – Eureka area. Originally discovered in 1887 the operation didn't really become a substantial one for 10 years. Its peak was in the first few years of the 20th century after which it was staggered by 2 major fires and an avalanche. By the end of the First World War the mine was not doing well and it finally closed in 1923 just after extending the American Tunnel.

American tunnel was originally part of the Gold King Mine at Gladstone. On USGS topographic maps it is still labeled as such. The actual working Gold King Mine's level 7, the main production adit, is called the “Upper Gold King Mine” on modern topographic maps. The American Tunnel was begun in 1900, some 800 feet beneath level 7, but was only driven in about 700 ft. In 1922-3 the American tunnel was extended to 6233 feet from the portal, to a point beneath the Gold King's main workings, but the mine closed before any other development work could be done.

The Gold King Mine mined ore shoots in veins associated with faults related to the Eureka graben. The geology and ore deposits of the Gold King and other mines in the area is discussed by Burbank and Luedke (1969) and Ransome (1901).

In recent years the main concern in the area is the acid drainage discharging from the American Tunnel and many other adits in the region. Bulkheads were installed in the American Tunnel to stem the flow but the loss of deep drainage in the area has caused adjustments in the water table over a larger area because of interconnected mine workings or the pervasive fracturing. Although the Gold King Mine was never connected to the American Tunnel by raises or other workings, after the American Tunnel was plugged water drainage from the level 7 adit increased considerably. Remediation efforts led to a large spill of acid water and sludge in 2015. A paper entitled “Technical Evaluation of the Gold King Mine Incident” was produced by the U.S. Department of the Interior, Bureau of Reclamation, Technical Service Center. It contains lots of information including maps of the American Tunnel and other mine workings in the area.

Regions containing this locality

North America PlateTectonic Plate
Rocky Mountains, North AmericaMountain Range

Select Mineral List Type

Standard Detailed Strunz Dana Chemical Elements

Mineral List

8 valid minerals.

Detailed Mineral List:

Formula: PbTe
Reference: Minerals of Colorado (1997) Eckel, E. B.
Formula: AuTe2
Reference: Minerals of Colorado (1997) Eckel, E. B.
Formula: CuSO4 · 5H2O
Reference: Minerals of Colorado (1997) Eckel, E. B.
Formula: NiAsS
Reference: Minerals of Colorado (1997) Eckel, E. B.
Formula: Au
Reference: Rocks & Min.:63:366.
Formula: Ag2Te
Reference: Minerals of Colorado (1997) Eckel, E. B.
Formula: Au3AgTe8
Reference: Minerals of Colorado (1997) Eckel, E. B.
Formula: Ag3AuTe2
Reference: Minerals of Colorado (1997) E.B. Eckel

List of minerals arranged by Strunz 10th Edition classification

Group 1 - Elements
Group 2 - Sulphides and Sulfosalts
Group 7 - Sulphates, Chromates, Molybdates and Tungstates
Chalcanthite7.CB.20CuSO4 · 5H2O

List of minerals arranged by Dana 8th Edition classification

Metals, other than the Platinum Group
Group 2 - SULFIDES
AmBnXp, with (m+n):p = 2:1
AmXp, with m:p = 1:1
AmBnXp, with (m+n):p = 1:2
Chalcanthite29.6.7.1CuSO4 · 5H2O

List of minerals for each chemical element

H ChalcanthiteCuSO4 · 5H2O
O ChalcanthiteCuSO4 · 5H2O
S ChalcanthiteCuSO4 · 5H2O
S GersdorffiteNiAsS
Ni GersdorffiteNiAsS
Cu ChalcanthiteCuSO4 · 5H2O
As GersdorffiteNiAsS
Ag HessiteAg2Te
Ag KrenneriteAu3AgTe8
Ag PetziteAg3AuTe2
Te AltaitePbTe
Te CalaveriteAuTe2
Te HessiteAg2Te
Te KrenneriteAu3AgTe8
Te PetziteAg3AuTe2
Au GoldAu
Au CalaveriteAuTe2
Au KrenneriteAu3AgTe8
Au PetziteAg3AuTe2
Pb AltaitePbTe

Regional Geology

This geological map and associated information on rock units at or nearby to the coordinates given for this locality is based on relatively small scale geological maps provided by various national Geological Surveys. This does not necessarily represent the complete geology at this locality but it gives a background for the region in which it is found.

Click on geological units on the map for more information. Click here to view full-screen map on

Miocene - Eocene
5.333 - 56 Ma

ID: 3190650
Cenozoic volcanic rocks

Age: Cenozoic (5.333 - 56 Ma)

Stratigraphic Name: San Juan Mountains

Comments: Southern Rocky Mountains

Lithology: Intermediate-felsic volcanic rocks

Reference: Chorlton, L.B. Generalized geology of the world: bedrock domains and major faults in GIS format: a small-scale world geology map with an extended geological attribute database. doi: 10.4095/223767. Geological Survey of Canada, Open File 5529. [154]

23.03 - 33.9 Ma

ID: 2813930
Intra-ash flow andesitic lavas

Age: Oligocene (23.03 - 33.9 Ma)

Comments: Original map source: Green, G.N., 1992, The Digital Geologic Map of Colorado in ARC/INFO Format: U.S. Geological Survey Open-File Report 92-0507, 9 p., scale 1:500,000.

Lithology: Major:{andesite}

Reference: Horton, J.D., C.A. San Juan, and D.B. Stoeser. The State Geologic Map Compilation (SGMC) geodatabase of the conterminous United States. doi: 10.3133/ds1052. U.S. Geological Survey Data Series 1052. [133]

Data and map coding provided by, used under Creative Commons Attribution 4.0 License


Sort by

Year (asc) Year (desc) Author (A-Z) Author (Z-A)
Burbank, W.S. and Luedke R.G. (1969), Geology and Ore Deposits of Eureka and Adjoining Districts, San Juan Mountains, Colorado, USGS Professional Paper 535.
Ransome, F. L., 1901, A report on the economic geology of the Silverton quadrangle: U.S. Geol. Survey Bun: 182, 265 p.

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