The Unnamed (Johns Hopkins Inlet) is a copper 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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Unnamed (Johns Hopkins Inlet) MRDS details
Site Name
Primary: Unnamed (Johns Hopkins Inlet)
Commodity
Primary: Copper
Secondary: Molybdenum
Secondary: Cobalt
Secondary: Gold
Secondary: Silver
Location
State: Alaska
District: Juneau
Land Status
Not available
Holdings
Not available
Workings
Not available
Ownership
Not available
Production
Not available
Deposit
Record Type: Site
Operation Category: Occurrence
Operation Type: Unknown
Years of Production:
Organization:
Significant:
Physiography
Not available
Mineral Deposit Model
Not available
Orebody
Not available
Structure
Not available
Alterations
Not available
Rocks
Not available
Analytical Data
Not available
Materials
Ore: Chalcopyrite
Ore: Chrysocolla
Ore: Limonite
Ore: Malachite
Ore: Molybdenite
Comments
Comment (Workings): Workings / Exploration = There are no mine workings. A grab sample representative of a shear zone in granitic rock contained 1500 ppm copper and 30 ppm molybdenum (MacKevett and others, 1978, sample 65, table 9). The U.S. Bureau of Mines (Kimball and others, 1978) collected float samples at about 150 feet elevation, in an area underlain by hornfels, that contained 4600 ppm copper, 300 ppm cobalt, 7 ppm silver, and 0.05 gold (p. C-172). A selected sample of a veinlet in hornfels at about 300 feet elevation contained greater then 2000 ppm molybdenum and 610 ppm copper.
Comment (Deposit): Other Comments = the area has numerous iron-stained areas, contact zones, and has widespread weak geochemical anomalies in copper and molybdenum. Favorable area for contact or intrusive-related shear zone-type deposits. The area is in Glacier Bay National Park and Preserve.
Comment (Geology): Geologic Description = Argillite, phyllite, and slate of Permian and Permian (?) age are cut by a small foliated granite pluton of Cretaceous age (Brew and others, 1978, plate IA). Kimball and others (1978, p.C149, fig. C38 ) reported volcanic rock, chert, and sulfides. MacKevett and others (1971, table 9, p. 52) reported a 100- to 200-foot wide altered zone in granitic rocks which extended several hundred feet on strike: fracture surfaces were stained with malachite, chrysocolla, and limonite. ? A grab sample collected by the U.S. Geological Survey contained 1500 ppm copper and 30 ppm molybdenum. Float samples collected by the U.S. Bureau of Mines (Kimball and others, 1978) contained as much as 4,600 ppm copper, 7 ppm silver, and 0.05 ppm gold. A rock sample collected by the Bureau contained more than 2000 ppm molybdenum and 610 ppm copper.
Comment (Reference): Primary Reference = Kimball and others, 1978
Comment (Deposit): Model Name = Mineralized shear zone; possible volcanogenic mineralization.
Comment (Exploration): Status = Inactive
Comment (Geology): Age = Cretaceous .
References
Reference (Deposit): Cobb, E.H., 1972, Metallic mineral resources map of the Mount Fairweather quadrangle, AK: U.S. Geological Survey Miscellaneous Field Study Map MF-436, 1 sheet, scale 1:250,000.
Reference (Deposit): Cobb, E. H., 1981, Summaries of data and lists of references to metallic and selected non-metallic mineral occurrences in the Mt. Fairweather quadrangle, Alaska, Supplement to Open-file Report 78-316: U. S. Geological Survey Open-File Report 81-249B, 15 p.
Reference (Deposit): Cobb, E.H., 1981, Summaries of data on and lists of references to metallic and selected nonmetallic mineral occurrences in the Mt. Fairweather quadrangle, Alaska; Supplement to Open-file Report 78-316; Part A, Summaries of data to January 1, 1980: U.S. Geological Survey Open-File Report 81-249-A, 20 p.
Reference (Deposit): Brew, D.A., Johnson, B.R., Grybeck, D., Griscom, A., Barnes, D.F., Kimball, A.L., Still, J.C., and Rataj, J.L., 1978, Mineral resources of the Glacier Bay National Monument Wilderness Study Area, Alaska: U.S. Geological Survey Open-File Report 78-494, 670 p.
Reference (Deposit): Kimball, A.L., Still, J.C., and Rataj, J.L., 1978, Mineral resources, in Brew, D. A., and others, Mineral resources of the Glacier Bay National Monument wilderness study area, Alaska: U.S. Geological Survey Open-File Report 78-494, p. C1-C375.
Reference (Deposit): MacKevett, E.M., Jr., Brew, D.A., Hawley, C.C., Huff, L.C., and Smith, J.G., 1971, Mineral resources of Glacier Bay National Monument, Alaska: U.S. Geological Survey Professional Paper 632, 90 p., 12 plates, scale 1:250,000.
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