Shumagin

Prospect in Alaska, United States with commodities Silver, Gold, Arsenic, Copper, Mercury, Lead, Tellurium, Zinc

Geologic information

Identification information

Deposit ID 10002295
MRDS ID A013199
Record type Site
Current site name Shumagin
Alternate or previous names Choumagin
Related records 10283127

Geographic coordinates

Geographic coordinates: -160.5763, 55.22534 (WGS84)
Relative position This prospect is at an elevation of about 300 feet, approximately 2,500 feet southwest of the head of Baralof Bay (Berg and Cobb, 1967, locality 7; Cobb, 1972 [MF 433], locality 4; MacKevett and Holloway, 1977, locality 4; Nokleberg and others, 1987, locality AP5; Wilson and others, 1988, locality 4). It is in the SE1/4 of sec. 19, T. 57 S., R. 74 W., of the Seward Meridian. This location is accurate.
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Geographic areas

Country State
United States Alaska

Commodities

Commodity Importance
Silver Primary
Gold Primary
Arsenic Secondary
Copper Secondary
Mercury Secondary
Lead Secondary
Tellurium Secondary
Zinc Secondary

Materials information

Materials Type of material
Arsenopyrite Ore
Galena Ore
Gold Ore
Pyrite Ore
Sphalerite Ore
Calcite Gangue
Quartz Gangue

Alteration

  • (Local) Strong argillic alteration is present as much as 148 feet from the Shumagin deposit. Quartz-sericite-pyrite alteration adjoins the Union vein and the matrix-supported quartz breccia. The presence of adularia is suspected (White and Queen, 1989).. There are indications of a broad aureole of mercury and arsenic as much as 250 feet from the Union vein.

Mineral occurrence model information

Model code 151
USGS model code 25d
Deposit model name Epithermal vein, Sado
Mark3 model number 28

Host and associated rocks

  • Host or associated Associated
    Rock type Volcanic Rock (Aphanitic)
    Stratigraphic age (youngest) Pliocene
  • Host or associated Associated
    Rock type Plutonic Rock > Granitoid > Granite
  • Host or associated Host
    Rock type Volcanic Rock (Aphanitic)

Nearby scientific data

(1) -160.5763, 55.22534

Comments on the geologic information

  • Geologic Description = The Shumagin gold deposit occurs in the Eocene to Oligocene Popof volcanic rocks (Wilson and others, 1995). The deposit is in the northeast section of the Aquila-Shumagin fault system, which strikes northeast across Unga Island.? the deposit consists of auriferous, sulfide-bearing quartz-calcite veins in a fault that trends N 60 E and dips 80 to 85 southeast. The veins and fault can be traced approximately 4,000 feet along strike and to a depth of 765 feet. The mineralization is interpreted as a fault-controlled epithermal, volcanic-hosted vein deposit (White and Queen, 1989). The hanging wall is tuff, and the footwall is andesite. Movement on the fault is suggested to be high-angle reverse.? the deposit comprises of four individual veins, two vein systems, and two fault breccia units. Within the fault, the mapped units from oldest to youngest are pyrite-rich cataclasite, clast-supported fault breccia, the Union vein, and matrix-supported quartz breccia (White and Queen, 1989). the total thickness of these units averages approximately 40 feet. Veins that are peripheral to or cut the main vein and fault system include the Lucky Friday and Greenbaum veins, the Vuggy Watercourse vein, and carbonate veins. Gold is most abundant in the Union vein, which generally is considered to be the principal gold deposit.? the Union vein is a composite vein consisting of a 10-foot-wide zone of closely-spaced quartz veins in the hanging wall tuff. Individual veins are sinuous, vuggy, and generally less than 30 inches wide. Native gold occurs, with finely crystalline arsenopyrite, pyrite, galena, and sphalerite. Precious-metal grades range from a trace throughout wide zones to more than 10 ounces of gold and 150 ounces of silver per ton in narrow zones. A strong correlation exists between gold, silver, and tellurium, indicating that some of the precious metals probably occur as tellurides (White and Queen, 1989). Singer (1999) suggests that this is a Sado-type gold deposit.? Atwood (1909) first described the prospect, whose workings at that time consisted of two tunnels 150 feet apart vertically. The lower one was 365 feet in length with a 75-foot crosscut. The upper tunnel was 79 feet in length with a 169-foot crosscut.? During the period 1983 to 1987, Alaska Apollo Gold Mines diamond drilled 23 holes totalling 9,269 feet, drilled 44 percussion holes, and cut 13 trenches through the vein and fault. At that time the deposit was estimated to contain 300,000 tons of ore grading 0.5 ounce of gold per ton. In 1989 Ballatar Exploration core-drilled approximately 6,000 feet into the deposit.? In 1986 Battle Mountain Exploration Company mapped and sampled the deposit and relogged the core. Analysis of the data indicated an ore shoot approximately 400 feet long, 5 to 30 feet thick, and plunging 45 degrees to the northeast in the plane of the fault (Ellis and Apel, 1990). A deep hole drilled by Alaska Apollo Gold Mines into the shoot cut 27 feet of rock containing 0.46 ounce of gold per ton at 600 feet down dip. The deposit was estimated by Battle Mountain Exploration company to contain 352,000 tons of ore grading 0.299 ounce of gold per ton. In 1990 Battle Mountain Exploration Company drilled a 1,022-foot core hole collared on Aleut Corporation land and inclined to hit the deposit at depth. The hole cut 18 feet of rock containing 0.47 ounce of gold per ton at 900 feet.? In 1987 during road building, a 500-foot-long, faulted eastern extension of the Shumagin vein was uncovered, mostly on Aleut Corporation land. Battle Mountain Exploration Company mapped and sampled this section of vein. It was found to be a large, weakly mineralized, south-dipping vein structure, locally as much as 50 feet thick. Metal values obtained were as much as 680 ppb gold, 12.1 ppm silver, 234 ppm arsenic and 2,000 ppb mercury (Ellis and Apel, 1990).
  • Age = Eocene or younger.

Economic information

Economic information about the deposit and operations

Development status Prospect
Commodity type Metallic

Comments on exploration

  • Status = Probably inactive

Mining district

District name Alaska Peninsula

Reserves and resources

  • Type In-situ
    Estimate year 1985
    Total resources 403,341,000mt ore
    Remarks Entry carried over from Old MRDS or added later (i.e. it did not originate in ARDF)
    Commodity Subtype Grade units Group Importance Year
    Gold Au 11.07 g/mt Gold Major 1985
    Silver Ag 53.13 g/mt Silver Minor 1985

Comments on the reserve resource information

  • Reserves = A resource of 300,000 tons grading 0.5 ounce of gold per ton was estimated from the exploration work done by Alaska Apollo Gold Mines in 1983 to 1987. Battle Mountain Exploration Company evaluated the deposit in 1986 at 352,000 tons grading 0.299 ounce of gold per ton. Queen (1988) estimated a resource of 270,000 tons grading 0.49 ounce of gold and 1.97 ounces of silver per ton.

Comments on the workings information

  • Workings / Exploration = Atwood (1909) described two tunnels with crosscuts at the time of his visit. During the period 1983-1987 Alaska-Apollo Gold Mines diamond drilled 23 holes totalling 9,269 feet. They also drilled 44 percussion holes and cut 13 trenches. In 1989 Ballatar Exploration diamond drilled approximately 6,000 feet into the deposit. From 1986 to 1990 Battle Mountain Exploration Company mapped and sampled the deposit and logged the drill core. They also drilled a 1,022-foot hole into the deposit where it dips south beneath Aleut Corporation land. In 1987 and 1988 the deposit was mapped and sampled in detail by the U.S. Geological Survey and Alaska Apollo Gold Mines.

Reference information

Links to other databases

Agency Database name Acronym Record ID Notes
USGS Mineral Resources Data System MRDS A013199
USGS Alaska Resource Data File ARDF PM064

Bibliographic references

  • Deposit

    Martin, G.C., 1905, Gold deposits of the Shumagin Islands, in Brooks A.H., Mineral resources of Alaska in 1904: U.S. Geological Survey Bulletin 259, p. 100-101.

  • Deposit

    Atwood, W.W., 1909, Mineral resources of southwest Alaska, in Brooks, A.H., and others, Mineral resources of Alaska in 1908: U.S. Geological Survey Bulletin 379, 411 p.

  • Deposit

    Atwood, W.W., 1911, Geology and mineral resources of parts of the Alaska Peninsula: U.S. Geological Survey Bulletin 467, 137 p.

  • Deposit

    Webber, B.S., Moss, J.M., Rutledge, F.A., and Sanford, R.S., 1946, Reconnaissance examinations of parts of the Alaska Peninsula and Aleutian Islands southwestern Alaska: U.S. Bureau of Mines, unpublished report of investigations, 40 p. (Unpublished report held by the U.S. Geological Survey, Anchorage.)

  • Deposit

    Berg, H.C., and Cobb, E.H., 1967, Metalliferous Lode Deposits of Alaska. U.S. Geological Survey Bulletin 1246, 254 p.

  • Deposit

    Cobb, E.H., 1980, Summaries of data and lists of references to metallic and selected nonmetallic mineral deposits in fifteen quadrangles in southwestern and west-central Alaska: U.S. Geological Survey Open-File Report 80-909, 103 p.

  • Deposit

    Angeloni, L.M., Wilson, F.H., and Sutlet, S., 1985, Map and tables showing preliminary rock geochemical data, Port Moller, Stepovak Bay, and Simeonof Island quadrangles, Alaska: U.S. Geological Survey Open-File Report 85-470, 179 p., 1 map sheet, scale 1:250,000.

  • Deposit

    Nokleberg, W.J., Bundtzen, T.K., Berg, H.C., Brew, D.A., Grybeck, D.J., Robinson, M.S., Smith, T.E., and Yeend, W., 1987, Significant metalliferous lode deposits and placer districts of Alaska: U.S. Geological Survey Bulletin 1786, 104 p.

  • Deposit

    Queen, L.D., 1988, Geologic report on Shumagin claims, Unga Island, Alaska: Report for Alaska Apollo Gold Mines, 7 p. (Unpublished report held by the U.S. Geological Survey, Anchorage)

  • Deposit

    Wilson, F.H., White, W.H., and DuBois, G.D., 1988, Brief descriptions of mines, prospects, and mineral occurrences in the Port Moller and Stepovak Bay quadrangles, Alaska Peninsula: U.S. Geological Survey Open-File Report 88-666, 128 p., scale 1:250,000.

  • Deposit

    Ellis, W.T., and Apel, R.A., 1989, Unga/Alaska Peninsula 1989 final report: Battle Mountain Exploration Company report, 41 p., 28 map sheets at various scales. (Report held by the Aleut Corporation, Anchorage, Alaska.)

  • Deposit

    White, W.H., and Queen, L.D., 1989, Preliminary geologic and rock-chip geochemical data from drill core and trenches at the Shumagin gold deposit, Unga Island, Alaska: U.S. Geological Survey Open-File Report 89-361, 11 p.

  • Deposit

    Ellis, W.T., and Apel, R.A., 1990, Unga/Alaska Peninsula 1990 final report, Battle Mountain Exploration Company report, 49 p., 29 map sheets at various scales. (Report held by the Aleut Corporation, Anchorage, Alaska.)

  • Deposit

    Wilson, F.H., Detterman, R.L., Miller, J. W., and Case, J.E., 1995, Geologic map of the Port Moller, Stepovak Bay, and Simeonof Island quadrangles, Alaska: U.S. Geological Survey Miscellaneous Investigation Series Map I-2272, 1 map sheet, scale 1:250,000.

  • Deposit

    White, W.H., and Queen, L.D., 1996, Description of the Shumagin epithermal gold vein deposit, in Wilson, Frederic H., and others, Maps showing resource assessment of Port Moller, Stepovak Bay, and Simeonof Island quadrangles, Alaska Peninsula: U.S. Geological Survey Miscellaneous Field Studies Map MF-2155-F, 45 p., 2 map sheets, scale 1:250,000.

  • Deposit

    Riehle, J.R., editor, 1999, Introduction to the present study, previous studies, and a descriptive summary of the vein systems and their production history, 10 p., in A Geological and geophysical study of the gold-silver vein system of Unga Island, southwestern Alaska: U.S. Geological Survey Open-File Report 99-136, CD-ROM.

  • Deposit

    Singer, D.A., 1999, Classifying the Shumagin and Alaska Apollo deposits, in Geological and geophysical setting of the gold-silver vein system of Unga Island, southwestern Alaska: U.S. Geological Survey Open-File Report 99-136, 6 p., CD-ROM.

  • Deposit

    Wedow, Helmuth, Jr., White, M.G., and Moxham, R.M., 1952, Interim report on an appraisal of the uranium possibilities of Alaska: U.S. Geological Survey Open-File Report 52-165, 124 p.

  • Deposit

    MacKevett, E.M., Jr., and Holloway, C.D., 1977, Map showing metalliferous mineral deposits in the western part of southern Alaska: U.S. Geological Survey Open-File Report 77-169-F, 38 p., 1 sheet, scale 1:1,000,000.

Comments on the references

  • Primary Reference = White and Queen, 1989

General comments

Subject category Comment text
Deposit Model Name = Sado epithermal gold vein (Cox and Singer, 1986; model 25d)

Reporter information

Type Date Name Affiliation Comment
Reporter 30-DEC-00 S.H. Pilcher U.S. Geological Survey