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Hoadley

Prospect in Alaska, United States with commodities Gold, Bismuth
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Sections on this page
  1. Identification information
  2. Geographic coordinates
  3. Site location context
  4. Geographic areas
  5. Commodities
  6. Materials information
  7. Alteration
  8. Mineral occurrence model information
  9. Host and associated rocks
  10. Nearby scientific data
  11. Economic information about the deposit and operations
  12. Mining district
  13. Links to other databases
  14. Bibliographic references
  15. General comments
  16. Reporter information

Geologic information

Identification information

Deposit ID 10094031
MRDS ID A012326
Record type Site
Current site name Hoadley
Alternate or previous names Hoadley Brothers
Related records 10234249

Geographic coordinates

Geographic coordinates: -131.68566, 55.36085 (WGS84)
Relative position The Hoadley prospect is at an elevation of about 350 feet, approximately 0.3 mile northwest of Hoadley Creek, and about 0.5 mile southeast of the dam at the foot of Carlanna Lake. The site is in section 14, T. 75 S., R. 90 E., of the Copper River Meridian. It corresponds to loc. 62 in Elliott and others (1978), and to loc. 270 in Maas and others (1995). The location is accurate within about 0.1 mile. ? Also see Additional comments.

Site location context

Political divisions (FIPS codes)

Ketchikan Gateway(Borough)

Alaska(state)

United States(country)

North America(continent)

Land(continent)

USGS map quadrangles

Ketchikan B-6(quadrangle 1:63,360 scale)

Ketchikan SW(quadrangle 1:100,000 scale)

Ketchikan(quadrangle 1:250,000 scale)

Hydrologic units (watersheds)

Ketchikan(hydrologic unit)

Southern Southeast Alaska(hydrologic accounting unit)

Southeast Alaska(hydrologic subregion)

Alaska(hydrologic region)

Geographic areas

Country State
United States Alaska

Commodities

Commodity Importance
Gold Primary
Bismuth Critical Secondary

Materials information

Materials Type of material
Arsenopyrite Ore
Gold Ore
Pyrite Ore
Pyrrhotite Ore
Tetradymite Ore
Quartz Gangue

Alteration

  • (Local) Greenschist-grade metasedimentary country rocks are contact metamorphosed to hornblende hornfels near contacts of Tertiary intrusive rocks.

Mineral occurrence model information

Model code 85
USGS model code 22c
Deposit model name Polymetallic veins
Mark3 model number 46
Model code 273
USGS model code 36a
Deposit model name Low-sulfide Au-quartz vein
Mark3 model number 27

Host and associated rocks

  • Host or associated Associated
    Rock type Plutonic Rock > Mafic Intrusive Rock > Gabbro
  • Host or associated Host
    Rock type Plutonic Rock > Mafic Intrusive Rock > Gabbro

Nearby scientific data

(1) -131.68566, 55.36085
ListMap

Economic information

Comments on the geologic information

  • Geologic Description = This part of Revillagigedo Island is underlain mainly by marine, pelitic sedimentary rocks and subordinate andesitic or basaltic volcanic rocks that are intruded by Cretaceous stocks, sills, and dikes of feldspar-porphyritic granodiorite, and by a stock and probably related plugs of Tertiary gabbro (Berg and others, 1988). The strata were regionally metamorphosed to greenschist-grade phyllite and semischist in Late Cretaceous time. They subsequently were contact metamorphosed to hornblende hornfels: locally, near some of the Cretaceous granodiorite contacts, and, more widely, peripheral to the Tertiary gabbro. The premetamorphic age range of the strata is uncertain. Berg and others (1988) note that they closely resemble Upper Jurassic to mid-Cretaceous flysch and volcanic rocks nearby on Gravina Island. The country rocks are cut by a high-angle fault along Tongass Narrows that displays about 4 miles of right-lateral offset.? the Hoadley deposit consists of sulfide-bearing quartz veins and argillaceous schists that strike northwest and are intruded by sills or dikes ranging in composition from syenite to gabbro (Wright and Wright, 1980, p. 151-152). The veins are mainly in the intrusive rocks, vary from 4-24 inches thick, and are up to a few hundred feet long. An older set of veins contains chiefly pyrite and pyrrhotite and strikes N and dips W. A younger set of thinner veins, characterized by arsenopyrite, free gold, and minor tetradymite, strikes NW and dips SW. According to Maas and others (1995, loc. 270: p. 194-200), the deposit, which in 1995 was covered by a condominium, is at a syenite-slate contact and consists of a quartz vein containing bands and disseminations of pyrite and arsenopyrite. A 1.5-foot-wide sample across vein rubble contained 88.25 ppm Au (Maas and others, 1995). ? the Hoadley prospect was discovered around 1900 and developed in the early 1900s by opencuts, adits, and a 27-foot shaft. Other developments included an arrastre and a Gibson mill. A small amount of gold probably was recovered at that time, but there is no public record of any such production.
  • Age = Cretaceous or younger.

Economic information about the deposit and operations

Development status Prospect
Commodity type Metallic

Mining district

District name Ketchikan

Comments on the production information

  • Production Notes = A small amount of gold probably was recovered in the early 1900s, but there is no public record of any such production.

Comments on the workings information

  • Workings / Exploration = The Hoadley prospect was discovered around 1900 and developed by opencuts, adits, and a 27-foot shaft. Other early developments included an arrastre and a Gibson mill. In 1995, the old workings were covered by a condominium. A 1.5-foot-wide sample across vein rubble contained 88.25 ppm Au (Maas and others, 1995).

Reference information

Bibliographic references

Comments on the references

  • Primary Reference = Wright and Wright, 1908; Maas and others, 1995

General comments

Subject category Comment text
Deposit Model Name = Polymetallic veins or low-sulfide, Au-quartz veins (Cox and Singer, 1986; models 22c or 36a)
Deposit Other Comments = the property has been covered by housing construction in the city of Ketchikan. In some early reports, the prospect was also referred to as Hoadley Brothers (Cobb and Elliott, 1980, p. 56).

Reporter information

Type Date Name Affiliation Comment
Reporter 02-JUL-1999 H.C. Berg U.S. Geological Survey

Beyond USGS

Supplemental information added by qvyshift.com. Not part of the original USGS MRDS record.

Maps centered on this site

Authoritative Alaska resources

These are landing pages for further research — the state agencies don't currently expose per-mine deep links.