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Rainy Day

Prospect in Alaska, United States with commodities Gold, Lead, Zinc
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Geologic information

Identification information

Deposit ID 10001559
MRDS ID A012307
Record type Site
Current site name Rainy Day
Related records 10161273

Geographic coordinates

Geographic coordinates: -131.96985, 55.61474 (WGS84)
Relative position The Rainy Day prospect is at an elevation of about 200 feet, approximately 0.2 mile inland from the southwest shore of Helm Bay, and about 1.4 miles from the mouth of the bay. The site is in section 19, T. 72 S., R. 88 E., of the Copper River Meridian. It corresponds to loc. 251 in Maas and others (1995, fig. 46), and to loc. 31 in Elliott and others (1978). The location is accurate within 0.1 mile.
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Geographic areas

Country State
United States Alaska

Commodities

Commodity Importance
Gold Primary
Lead Secondary
Zinc Secondary

Materials information

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

Mineral occurrence model information

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 Host
    Rock type Plutonic Rock > Granitoid > Granite

Nearby scientific data

(1) -131.96985, 55.61474
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Comments on the geologic information

  • Geologic Description = The country rocks at this site are flyschlike metasedimentary rocks that gradationally intertongue with andesitic and basaltic metatuff (Berg and others, 1988, p. 17-19). The strata were regionally metamorphosed to greenschist-grade phyllite and semischist in Late Cretaceous time (Brew, 1996, p. 27). Their premetamorphic age is uncertain. Berg and others (1988, p. 17) state that they closely resemble Upper Jurassic to mid-Cretaceous marine flysch and volcanic rocks nearby on Gravina Island. At the prospect, the bedded rocks are intruded by a 600-1000-foot-thick dike of granite porphyry (Wright and Wright, 1908, p. 156) or granodiorite (Maas and others, 1995, fig. 46). The dike probably is Late Cretaceous or younger, assuming that it postdates the regional metamorphism.? the deposit consists of a 3- to 3.5-foot-thick quartz fissure vein in granite porphyry (Brooks, 1902, p. 58; Wright and Wright, 1908, p. 156). The vein strikes northwest and has been traced in outcrop for 300-500 feet; it contains small amounts of pyrite, sphalerite, and galena, and minute particles of native gold. The prospect was developed in the early 1900s by an opencut and a 105-foot tunnel. Maas and others (1995, table 25) report the following average metal contents in their samples from the Rainy Day prospect: 6.28 ppm Au, 13.2 ppm Ag, 48 ppm Cu, 732 ppm Pb, and 14 ppm Zn.? Fluid inclusion studies of quartz vein material from several of the Helm Bay lodes suggest that the veins formed at temperatures and pressures consistent with conditions during the Late Cretaceous greenschist-grade regional metamorphism (Maas and others, 1995, p. 184).
  • Age = Late Cretaceous.

Economic information

Economic information about the deposit and operations

Development status Prospect
Commodity type Metallic

Mining district

District name Ketchikan

Comments on the workings information

  • Workings / Exploration = The prospect was developed in the early 1900s by an opencut and a 105-foot tunnel. Maas and others (1995, table 25) report the following average metal contents in their samples from the Rainy Day prospect: 6.28 ppm Au, 13.2 ppm Ag, 48 ppm Cu, 732 ppm Pb, and 14 ppm Zn.

Reference information

Links to other databases

Agency Database name Acronym Record ID Notes
USGS Mineral Resources Data System MRDS A012307
USGS Alaska Resource Data File ARDF KC031

Bibliographic references

  • Deposit

    Brooks, A.H., 1902, Preliminary report on the Ketchikan mining district, Alaska, with an introductory sketch of the geology of southeastern Alaska: U.S. Geological Survey Professional Paper 1, 120 p.

  • Deposit

    Wright, F.E., and Wright, C.W., 1908, The Ketchikan and Wrangell mining districts, Alaska: U.S. Geological Survey Bulletin 347, 210 p.

  • 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.

  • 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.

  • 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

    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.

Comments on the references

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

General comments

Subject category Comment text
Deposit Model Name = Low-sulfide gold-quartz veins (Cox and Singer, 1956; model 36a)

Reporter information

Type Date Name Affiliation Comment
Reporter 30-JUN-99 H.C. Berg U.S. Geological Survey