The Lucky Four 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
Satelite View
MRDS mine locations are often very general, and in some cases are incorrect. Some mine remains have been covered or removed by modern industrial activity or by development of things like housing. The satellite view offers a quick glimpse as to whether the MRDS location corresponds to visible mine remains.
Lucky Four MRDS details
Site Name
Primary: Lucky Four
Secondary: Hump Island
Commodity
Primary: Copper
Secondary: Gold
Location
State: Alaska
District: Ketchikan
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
Orebody
Not available
Structure
Not available
Alterations
Alteration Type: L
Alteration Text: Locally intense silicification, argillization, and sericitization. Local iron-staining and oxidation of copper minerals.
Rocks
Not available
Analytical Data
Not available
Materials
Ore: Chalcopyrite
Ore: Molybdenite
Ore: Pyrite
Gangue: Quartz
Comments
Comment (Workings): Workings / Exploration = Assays of samples of sulfide-bearing veins and altered country rocks collected in the early 1990s by the U.S. Bureau of Mines ranged from 806-3080 ppm Cu (average: 2064 ppm Cu) and 6-236 ppm Mo (average: 69 ppm Mo), along with as much as 3.6 ppm Ag, 3837 ppb Au, 172 ppm Bi, and 11 ppm Te (Maas and others, 1995, p. 278 and fig. 73). Other samples of sulfide-bearing altered rocks contained up to 2.0% Cu, 10 ppm Ag, 30 ppm Mo, and 500 ppm Co (Elliott and others, 1978, loc. 41).
Comment (Geology): Age = Probably Late Cretaceous.
Comment (Deposit): Model Name = Metamorphosed porphyry Cu deposit (Cox and Singer, 1986; model 17)
Comment (Geology): Geologic Description = The country rocks on and near Hump Island consist chiefly of flyschlike metasedimentary rocks and subordinate andesitic and basaltic metavolcanic rocks that are intruded by Cretaceous feldspar-porphyritic granodiorite stocks, sills, and dikes (Berg and others, 1988). The strata were regionally metamorphosed to greenschist-grade phyllite and semischist in Late Cretaceous time (Brew, 1996, p. 27). Near some of the granodiorite contacts, the phyllite and semischist were subsequently contact metamorphosed to hornblende hornfels (Berg and others, 1988). The premetamorphic age range of the strata is unknown; Berg and others (1988, p. 17) note that they closely resemble Upper Jurassic and mid-Cretaceous marine flysch and volcanic rocks nearby on Gravina Island.? Hump Island consists largely of intensely hydrothermally altered and locally sulfide-bearing rocks. Maas and others (1995, p. 277) describe the island as a small, foliated, Cretaceous quartz diorite or quartz monzonite pluton that intrudes Jurassic or Cretaceous mafic to felsic volcanic rocks and interbedded pelitic sedimentary rocks. Weak porphyry copper mineralization accompanied emplacement of the pluton, along with silicic and argillic alteration of the surrounding country rocks. The east side of the island is underlain by felsic volcanic rocks that have been altered to quartz-sericite-pyrite schist with a high silica content. The west side is intensely argillized pelitic schist. ? the deposit consists of pyrite, chalcopyrite, and minor molybdenite that form veinlets and disseminations in the hydrothermally altered rocks. Locally, chalcopyrite, and possibly other sulfides, occur as small masses in quartz veinlets (Maas and others, 1995, p. 278). Assays of samples of sulfide-bearing veins and altered country rocks collected in the early 1990s by the U.S. Bureau of Mines ranged from 806-3080 ppm Cu (average: 2064 ppm Cu) and 6-236 ppm Mo (average: 69 ppm Mo), along with as much as 3.6 ppm Ag, 3837 ppb Au, 172 ppm Bi, and 11 ppm Te (Maas and others, 1995, p. 278 and fig. 73). Other samples of sulfide-bearing altered rocks contained up to 2.0% Cu, 10 ppm Ag, 30 ppm Mo, and 500 ppm Co (Elliott and others, 1978, loc. 41). Maas and others (1995, p. 278) classify the prospect as a metamorphosed porphyry Cu deposit, and note that it is the only one known in the Ketchikan district.
Comment (Reference): Primary Reference = Maas and others, 1995
References
Reference (Deposit): Elliott, R.L., Berg, H.C., and Karl, Susan, 1978, map and table describing metalliferous and selected nonmetalliferous mineral deposits, Ketchikan and Prince Rupert quadrangles, Alaska: U.S. Geological Survey Open-file Report, 78-73-B,17 p., scale 1:250,000.
Reference (Deposit): Berg, H.C., Elliott, R.L., and Koch, R.D., 1988, Geologic map of the Ketchikan and Prince Rupert quadrangles, southeastern Alaska: U.S. Geological Survey Mineral Investigations Series Map MF-1807,27 p., scale 1:250,000.
Reference (Deposit): Maas, K.M., Bittenbender, P E., and Still, J.C., 1995, Mineral investigations in the Ketchikan mining district, southeastern Alaska: U.S. Bureau of Mines Open-File Report 11-95, 606 p.
Reference (Deposit): Brew, D.A., 1996, Geologic map of the Craig, Dixon Entrance, and parts of the Ketchikan and Prince Rupert quadrangles, southeastern Alaska: U.S. Geological Survey Miscellaneous Field Studies Map MF-2319, 53 p., 1 sheet, scale 1:250,000.
The Top Ten Gold Producing States
These ten states contributed the most to the gold production that built the West from 1848 through the 1930s. The Top Ten Gold Producing States.
