Copenhagen Hill

Prospect in Alaska, United States with commodities Copper, Silver, Gold

Geologic information

Identification information

Deposit ID 10307780
Record type Site
Current site name Copenhagen Hill

Geographic coordinates

Geographic coordinates: -154.62897, 63.51449 (WGS84)
Relative position The Copenhagen Hill prospect is situated near the summit of an isolated hill about 1 mile (1.6 km) north of Cottonwood Creek at an elevation of 2,450 feet (746 m) in Section 9, T. 23 S., R. 22 E., of the Kateel River Meridian. Location is known to within about 500 feet (152 m).
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Geographic areas

Country State
United States Alaska

Commodities

Commodity Importance
Copper Primary
Silver Secondary
Gold Secondary

Materials information

Materials Type of material
Chalcopyrite Ore
Pyrite Ore
Quartz Gangue
Tourmaline Gangue

Alteration

  • (Local) Tourmaline.

Mineral occurrence model information

Model code 78
USGS model code 20c
Deposit model name Porphyry Cu-Au
Mark3 model number 34

Nearby scientific data

(1) -154.62897, 63.51449

Comments on the geologic information

  • Geologic Description = The Copenhagen Hill prospect is the western-most copper-gold showing in a seven mile (11 km)-long, northeast trending belt of porphyry-like prospects through the central Mystery Mountains (DiMarchi and others, 1997). The hornfels is intruded by several porphyry dikes. Unlike other prospects in the Mystery Mountains, sulfides such as chalcopyrite, pyrite, and pyrrhotite are found in abundance in the hornfels. Quartz-tourmaline breccias are common within a 450 feet by 300 feet (137 m by 91 m) mineralized area. The Copenhagen Hill prospect is believed to be Late Cretaceous, based on inferred isotopic age of Mystery Mountains plutonic rocks (Moll and others, 1981). No assay data was found for this summary.
  • Age = the Copenhagen Hill prospect is believed to be Late Cretaceous, based on inferred isotopic age of Mystery Mountains plutonic rocks (Moll and others, 1981).

Economic information

Economic information about the deposit and operations

Development status Prospect

Comments on exploration

  • Status = Inactive

Mining district

District name McGrath

Comments on the workings information

  • Workings / Exploration = Regional exploration conducted by WGM Inc. in 1978 found the Copenhagen prospect (Andrews, 1978). During 1988 to 1990, ACNC conducted exploration including an airborne geophysical survey. During 1991 to 1997, ASA Inc. continued detailed exploration work at the Copenhagen prospect and throughout the Mystery Mountains. The Copenhagen Hill prospect is believed by DiMarchi and others (1997) to represent the western-most copper-gold anomalous area in a district-wide, porphyry-style metallic zonation (DiMarchi and others, 1997). No assay data was found for this summary.

Reference information

Links to other databases

Agency Database name Acronym Record ID Notes
USGS Alaska Resource Data File ARDF MD030

Bibliographic references

  • Deposit

    Andrews, Tom, 1978, Summary of Progress, Doyon Project, Mystery Mountains, (Block 10): Anchorage, Alaska, WGM Inc., 24 pages (Held by Doyon Ltd., as proprietary report 78-42).

  • Deposit

    Moll, E.J., Silberman, M.L., and Patton, W.W. Jr., 1981, Chemistry, mineralogy, and K-Ar ages of igneous and metamorphic rocks of the Medfra quadrangle, Alaska: U.S. Geological Survey Open-File Report 80-811C, 15 p., 2 sheets, scale 1:250,000.

  • Deposit

    DiMarchi, J.J., and Frantz, P.S., 1997, Annual Report for 1997-Doyon Option Lands, Block 10: ASA Inc.-Montague Gold Joint Venture Report, Volume II: Unpublished report, 189 p. (Report held by Doyon, Limited, Fairbanks, Alaska.)

Comments on the references

  • Primary Reference = DiMarchi and others, 1997

General comments

Subject category Comment text
Deposit Model Name = Porphyry Cu-Au (Cox and Singer, 1986; model no. 20c)
Deposit Other Comments = See Pork Chop (MD031), Mystery Mountains East (MD028), Frozen Creek (MD032), and Tarn (MD027) prospects.

Reporter information

Type Date Name Affiliation Comment
Reporter 06-JUN-98 Bundtzen, T.K. Pacific Rim Geological Consulting