Orange Hill

The Orange Hill is a copper, molybdenum, gold, and silver mine located in Alaska.

About the MRDS Data:

All mine locations were obtained from the USGS Mineral Resources Data System. The locations and other information in this database have not been verified for accuracy. It should be assumed that all mines are on private property.

Mine Info

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Site Name

Primary: Orange Hill

Commodity

Primary: Copper
Primary: Molybdenum
Primary: Gold
Primary: Silver

Location

State: Alaska
District: Chisana

Land Status

Not available

Holdings

Not available

Workings

Not available

Ownership

Not available

Production

Not available

Deposit

Record Type: Site
Operation Category: Prospect
Operation Type: Unknown
Years of Production:
Organization:
Significant:

Physiography

Not available

Mineral Deposit Model

Model Name: Porphyry Cu-Mo

Orebody

Not available

Structure

Not available

Alterations

Alteration Text: Central altered zone 400 m by 2000 m contain abundant biotite, quartz veinlets, minor k-feldspar, chlorite, and sericite cut by late stage anhydrite veins. Outer altered zones contain chlorite, minor sericite and anhydrite.

Rocks

Not available

Analytical Data

Not available

Materials

Ore: Chalcopyrite
Ore: Molybdenite
Ore: Pyrite
Gangue: Calcite
Gangue: Gypsum
Gangue: Quartz

Comments

Comment (Exploration): Status = Inactive

Comment (Workings): Workings / Exploration = Developed by open cuts, shafts and 14 adits totaling between 250 and 300 ft, of which most reportedly were caved in 1944 (USGS OFR 76). 3187 ft of drilling done in 1927 and 1928: 2021 ft in quartz diorite, 1166 ft in metamorphosed limestone.

Comment (Geology): Age = Early Cretaceous

Comment (Reserve-Resource): Reserves = Average grades from surface sampling: 0.25% Cu; all samples were below 0.4%; 0.01% TO 0.8% Mo; Au values from trace to 0.04 oz/ton, average Au grade estimated at 0.005 oz/ton; average Ag grade estimated at 0.01 oz/ton. Estimated 320 million tonnes of 0.35% Cu and 0.02% Mo.

Comment (Deposit): Other Comments = This record contains data which apply to both the porphyry Cu and the associated contact metamorphic (skarn) deposits at Orange Hill; for data specific to contact metamorphic deposits, see Lemon prospect (NB044).

Comment (Geology): Geologic Description = Pyrite, chalcopyrite, and molybdenite occur in quartz veinlets and as disseminations in large Cretaceous quartz diorite/granodiorite pluton. Pluton intrudes volcanic and sedimentary rocks of Permian and Triassic age. Associated skarn mineralization in metamorphosed limestone country rock (see Lemon deposit) contains Cu and Zn sulfide minerals. Plutonic rocks intruded by alaskite dikes which are crosscut by dikes of andesite, dacite, and basaltic porphyry. Other similar deposits (Bond Creek) in the pluton exhibit same mineralogy. Abundant biotite-quartz, quartz-sericite, and chlorite-sericite-epidote alteration. Late anhydrite veins common. Altered areas about 1,000 by 3,000 m. Associated skarns contain pyrite, chalcopyrite, bornite, and magnetite.

Comment (Deposit): Model Name = Porphyry, stockwork, skarn

References

Reference (Deposit): Hollister, V.F., Anzalone, S.A., and Richter, D.H., 1975, Porphyry copper belts of southern Alaska and contiguous Yukon Territory: CIM (Canadian Mining and Metallurgical) Bulletin, v. 68, no. 756, p. 104-112.

Reference (Deposit): Moffit, F.H., 1954, Geology of the eastern part of the Alaska Range and adjacent area: U.S. Geological Survey Bulletin 989-D, p. 63-218.

Reference (Deposit): Richter, D.H., 1973, Reconnaissance geological map of the Nabesna A-1 quadrangle, Alaska: U.S. Geological Survey Miscellaneous Investigations Series Map 1-789, scale 1:63,360.

Reference (Deposit): Richter, D.H., Singer, D.A., and Cox, D.P., 1975, Mineral resources map of the Nabesna quadrangle, Alaska: U.S. Geological Survey Miscellaneous Field Studies Map MF-655-K, scale 1:250,000.

Reference (Deposit): Moffit, F.H., 1943, Geology of the Nutzotin Mountains, Alaska, with a section on the igneous rocks, by R. C. Wayland, and Gold deposits near Nabesna, by R. C. Wayland, 1943: U.S. Geological Survey Bulletin 933-B, p. 103-199.

Reference (Deposit): Van Alstine, R.E., and Black, R.F., 1944, Mineral deposits at Orange, Hill, Alaska: U.S. Geological Survey Open-File Report 76, 16 p., 1 sheet.

Reference (Deposit): Richter, D.H., and Matson, N.A., 1970, Geochemical data from the Nabesna A-4 quadrangle, Alaska: U.S. Geological Survey Open-File Report 70-276, 14 p., 1 sheet, scale 1:63,360.

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