Herman Lode

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

Geologic information

Identification information

Deposit ID 10002293
MRDS ID A013198
Record type Site
Current site name Herman Lode
Alternate or previous names Trench, Popof Island Gold, Centennial

Geographic coordinates

Geographic coordinates: -160.49936, 55.3073 (WGS84)
Relative position This prospect is at an elevation of about 300 feet, approximately 2 miles south of the town of Sand Point (Berg and Cobb, 1967, locality 6; Cobb, 1972 [MF 433], locality 3; MacKevett and Holloway, 1977, locality 3; Wilson and others, 1988, locality 3). The 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
Zinc Secondary

Materials information

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

Alteration

  • (Local) The rocks in the area exhibit pervasive propylitic alteration. The mineralization is accompanied by enrichment in silica and potassium, resulting in deposition of adularia, sericite, and quartz. Argillic alteration is locally present. Calcite stockwork veining is widespread.

Host and associated rocks

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

Nearby scientific data

(1) -160.49936, 55.3073

Comments on the geologic information

  • Geologic Description = The rocks at this prospect are the Eocene to Oligocene Popof volcanic rocks (Wilson and others, 1995). At this locality they consist mostly of basalt flows and tuffs.? the names Herman Lode and Trench refer to prospects explored by several adits, pits, and a trench in the early 1900's. A mineralized zone 5 to 10 feet wide was reported to contain free gold (Atwood, 1909). The name Centennial was given to a gold deposit discovered in the same area in 1987 by Battle Mountain Exploration Company.? the Centennial deposit is a large, low grade, disseminated gold lode. The country rocks consist of basalt flows, plugs, dikes, tuffs, and epiclastic deposits that overlie a basement sedimentary complex. The main mineralized zone occurs in a window eroded through a basalt flow. The mineralization is thought to be controlled in part by a plug margin, and in part by north-northeast-trending high-angle faults and fracture zones from which mineralizing fluids spread out into surrounding permeable rock (Ellis and Harris, 1989). The gold is disseminated in the matrix of the basaltic tuffs and also occurs in fractures and veins that cut the flows. The distribution of the mineralization seems to have a lower limit at 240 to 400 feet above the sedimentary basement complex.? the gold is free and occurs in the plus-25-micron range (Ellis and Harris, 1989). Silver, mercury, and arsenic values are associated with the gold. The mineralization is accompanied by enrichment in silica and potassium, as shown by the presence of quartz, sericite, and adularia. Quartz and quartz-calcite veins and veinlets containing galena, sphalerite, pyrite, and some chalcopyrite were cut in some of the drill holes. Their relationship to the gold mineralization is not known.? In sea cliffs due south of the Centennial deposit, a zone of north-striking quartz-sulfide veins cuts tuffs and overlying flows. These veins may occupy the same structures that control the mineralization at the Centennial deposit. At the base of the cliff the vein zone is 10.5 feet wide and consists of five sulfide-bearing veins. At 175 feet vertically above the base, the zone is 50 feet wide and consists of 12 narrow, poorly mineralized veins. In the early 1900's a short adit was driven at the base of the zone. No assays of interest from this area were reported by Battle Mountain Exploration Company.
  • 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

Comments on the reserve resource information

  • Reserves = the resource is estimated at 4.8 million tons grading 0.042 ounce of gold per ton within 175 feet of the surface (Ellis and Harris, 1989).

Comments on the workings information

  • Workings / Exploration = In the early 1900's the prospect area was explored by tunnels, trenches, and pits. Battle Mountain Exploration Company evaluated the area in the late 1980s and carried out detailed mapping and sampling programs. Their exploration also included drilling 484 auger holes and 59 diamond drill holes, 7,275 feet of trenching, and magnetic and VLF-EM surveys.

Reference information

Links to other databases

Agency Database name Acronym Record ID Notes
USGS Mineral Resources Data System MRDS A013198
USGS Alaska Resource Data File ARDF PM096

Bibliographic references

  • 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

    Smith, P.S., 1932, Mineral industry of Alaska in 1929, in Smith, P.S., and others Mineral resources of Alaska, report on progress of investigations in 1929: U.S. Geological Survey Bulletin 824-A, p. 1-81.

  • 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

    Peterson, R.J., Lemmers, J., Handverger, P., Gallagher, J., Pilcher, R., East, J., Macleod, T., Bartels. E., 1982, Geology and precious metals potential Unga, Popof, and Korovin Islands, Shumagin Group, Aleutian Chain, Alaska: UNC Teton Exploration Drilling Company report, 127 p., 5 map sheets, various scales. (Report held by the Aleut Corporation, Anchorage, Alaska.)

  • 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

    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 Harris, D.E., 1989, Centennial prospect 1989 final report: Battle Mountain Exploration Company report, 48 p., 41 map sheets of 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

    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 = Ellis and Harris, 1989

General comments

Subject category Comment text
Deposit Model Name = Volcanic-hosted disseminated gold deposit
Deposit Other Comments = This site is located on land patented by, or interim-conveyed to, the Aleut Corporation.

Reporter information

Type Date Name Affiliation Comment
Reporter 23-DEC-2000 S.H. Pilcher U.S. Geological Survey