Hobo

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

Geologic information

Identification information

Deposit ID 10000197
MRDS ID A010233
Record type Site
Current site name Hobo
Alternate or previous names Swede
Related records 10136560

Geographic coordinates

Geographic coordinates: -130.04564, 56.02088 (WGS84)
Relative position The Hobo prospect, at the eastern edge of Section 35, is at an elevation of about 2400-2450 feet on a northwest-facing mountainside overlooking the confluence of the Salmon River and Texas Creek. It is about 1.0 mile east of the ruins at Ninemile (Elliott and Koch, 1981, p. 17, loc. 71). The location is accurate within about a quarter of a mile.? Also see Additional Comments field, below.
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Geographic areas

Country State
United States Alaska

Commodities

Commodity Importance
Silver Primary
Gold Primary
Copper Primary
Lead Primary
Zinc Primary

Materials information

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

Alteration

  • (Local) Greenstone country rock is impregnated with sulfide minerals.

Mineral occurrence model information

Model code 85
USGS model code 22c
Deposit model name Polymetallic veins
Mark3 model number 46

Host and associated rocks

  • Host or associated Host
    Stratigraphic age (youngest) Jurassic

Nearby scientific data

(1) -130.04564, 56.02088

Comments on the geologic information

  • Geologic Description = The country rocks in the area of this site are pelitic metasedimentary and subordinate andesitic (greenstone) metavolcanic strata of the Jurassic or older Mesozoic Hazelton Group, which is underlain and locally intruded by the Triassic Texas Creek Granodiorite; the Eocene Boundary Granodiorite, which intrudes the Hazelton and Texas Creek rocks; and still-younger Tertiary lamprophyre dikes, which cut all of the other rocks (Smith, 1973, 1977; Koch, 1996).? the deposit (Buddington, 1929, p. 84-85) consists of mineralized (pyritized) greenstone containing veins or veinlike replacements of pyrite, pyrrhotite, and sphalerite, and smaller amounts of chalcopyrite, galena, and arsenopyrite. Early assays show some gold and silver, generally in small and variable amounts. Another vein in greenstone contains pyrite, pyrrhotite, and a little arsenopyrite in quartz gangue; these sulfides carry about 0.2-0.58 oz Au per ton. Nearby quartz veins in a fissure zone in greenstone carry pyrite, galena, and sphalerite.? Elliott and Koch (1981, loc. 71) describe the deposit as greenstone that contains mineralized zones with seams, fracture facings, and veins of the same sulfides described by Buddington. Their report also refers to quartz veins and disseminated sulfides; to quartz and calcite as the principal gangue minerals; and to a reported 9 oz of Au per ton in some samples.? Concentrated sulfide samples from a shear zone on the Hobo prospect yielded an Eocene lead-isotope age (Maas and others, 1995, p. 254). The deposit, however, is similar in mineralogy, structural setting, and hostrock to isotopically dated Jurassic deposits nearby in the Hyder district (see, for example, BC065, BC067). The lode thus may be polygenetic, originating as a 'disseminated' deposit during Jurassic (Hazelton) island-arc volcanism (Alldrick, 1993), and then partly remobilized into shear zones during emplacement of the Boundary Granodiorite.
  • Age = Concentrated sulfide samples from a shear zone on the Hobo prospect yielded an Eocene lead-isotope age (Maas and others, 1995, p. 254). The deposit, however, is similar in mineralogy, structural setting, and hostrock to isotopically dated Jurassic deposits nearby in the Hyder district (see, for example, BC065, BC067). The lode thus may be polygenetic, originating as a 'disseminated' deposit during Jurassic (Hazelton) island-arc volcanism (Alldrick, 1993), and then partly remobilized into shear zones during emplacement of the Boundary Granodiorite.
  • Age = Host rock is similar to isotopically dated Jurassic deposits nearby.

Economic information

Economic information about the deposit and operations

Development status Prospect
Commodity type Metallic

Comments on exploration

  • Status = Inactive

Mining district

District name Hyder

Comments on the workings information

  • Workings / Exploration = Property explored by open cuts, probably mainly in the 1920's.? Early assays of sulfide samples show 0.2-0.58 oz Au per ton. Some samples reported to carry as much as 9 oz Au per ton.

Reference information

Links to other databases

Agency Database name Acronym Record ID Notes
USGS Mineral Resources Data System MRDS A010233
USGS Alaska Resource Data File ARDF BC071

Bibliographic references

  • Deposit

    Buddington, A.F., 1925, Mineral investigations in southeastern Alasaka: U.S. Geological Survey Bulletin 773, p. 71-139.

  • Deposit

    Buddington, A.F., 1929, Geology of Hyder and vicinity, southeastern Alaska, with a reconnaissance of Chickamin River: U.S. Geological Survey Bulletin 807, 124 p.

  • Deposit

    Smith, J.G., 1973, A Tertiary lamprophyre dike province in southeastern Alaska: Canadian Journal of Earth Sciences, v. 10, p. 408-420.

  • Deposit

    Smith, J.G., 1977, Geology of the Ketchikan D-1 and Bradfield Canal A-1 quadrangles, Alaska: U.S. Geological Survey Bulletin 1425, 49 p.

  • Deposit

    Cobb, E.H., 1978, Summary of references to mineral occurrences (other than mineral fuels and construction materials) in the Bradfield Canal quadrangle, Alaska: U.S. Geological Survey Open-File Report 78-922, 98 p.

  • Deposit

    Elliott, R.L., and Koch, R.D., 1981, Mines, prospects, and selected metalliferous mineral occurrences in the Bradfield Canal quadrangle, Alaska: U.S. Geological Survey Open-File Report 81-728-B, 23 p., 1 sheet, scales 1:250,000 and 1:63,360.

  • Deposit

    Alldrick, D.J., 1993, Geology and metallogeny of the Stewart mining camp, northwestern British Columbia: British Columbia Department of Mines and Petroleum Resources Bulletin 85, 105 p., 2 plates.

  • 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.

  • Deposit

    Koch, R.D., 1996, Reconnaissance geologic map of the Bradfield Canal quadrangle, southeastern Alaska: U.S. Geological Survey Open-File Report 81-728-A, 35 p., 1 sheet, scale 1:250,000.

Comments on the references

  • Primary Reference = Buddington, 1929

General comments

Subject category Comment text
Deposit Model Name = Polymetallic veins
Deposit Other Comments = the Hobo group was originally staked in 1919.? the Swede group (Buddington, 1925, p. 78) is probably the same as the Hobo group, but has also been referred to in descriptions of the Portland and Daly-Alaska properties (Cobb, 1978, p. 73).? Also see BC070.

Reporter information

Type Date Name Affiliation Comment
Reporter 17-MAY-1998 H. C. Berg U.S. Geological Survey