Reynolds-Alaska Development Co.

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

Geologic information

Identification information

Deposit ID 10093950
MRDS ID A010433
Record type Site
Current site name Reynolds-Alaska Development Co.

Geographic coordinates

Geographic coordinates: -146.56365, 60.86848 (WGS84)
Relative position This prospect is at an elevation of about 1700 feet, approximately 0.75 mile northeast of Copper Mountain. It is in S1/2 sec. 36, T. 11 S., R. 8 W., of the Copper River Meridian. The location is accurate to within 1000 ft. This prospect is shown as #12 in Cobb (1972: MF-392) and as C-79 in Jansons and others (1984).
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Geographic areas

Country State
United States Alaska

Commodities

Commodity Importance
Copper Primary
Silver Secondary
Zinc Secondary

Materials information

Materials Type of material
Chalcopyrite Ore
Pyrrhotite Ore
Sphalerite Ore
Calcite Gangue
Quartz Gangue

Mineral occurrence model information

Model code 90
USGS model code 24a
Deposit model name Massive sulfide, Cyprus
Mark3 model number 11

Host and associated rocks

  • Host or associated Host
    Rock type Metamorphic Rock > Metavolcanic Rock
    Rock unit name Orca Group
    Rock description Orca Group

Nearby scientific data

(1) -146.56365, 60.86848

Comments on the geologic information

  • Geologic Description = The country rocks at this prospect are mafic volcanic rocks and sedimentary rocks of the Tertiary Orca Group (Nelson and others, 1985). The deposit consists of chalcopyrite, pyrrhotite, and sphalerite in a 1-to 20- foot-wide shear zone in volcanic rocks (Capps and Johnson, 1915).? Capps and Johnson (1915) reported assays of 11.4 to 12.5% Cu and 0.18 oz Au and 0.26 oz Ag per ton. Later development included four adits with about 820 ft. of underground workings and some open cuts. Three of the adits are caved or flooded (Jansons and others, 1984). Chip samples from the open cuts contained 0.18% to 8.4% Cu, 170 ppm to 0.25% Zn, and 0.8 ppm to 28 ppm Ag (Jansons and other, 1984). Grab samples gave the following values: 100 ppm to 9.75% Cu, 100 ppm to 1.05% Zn, and 0.8 ppm to 9.5 ppm Ag.
  • Age = Probably Tertiary based on the age of the host rocks.

Economic information

Economic information about the deposit and operations

Development status Prospect
Commodity type Metallic

Comments on exploration

  • Status = Inactive

Mining district

District name Copper River

Comments on the reserve resource information

  • Reserves = Inferred reserves of 3000 tons @ 4.6% Cu, 0.14% Zn, and 15.65% Ag (Jansons and others, 1984).

Comments on the workings information

  • Workings / Exploration = Site was discovered in 1899 and by 1912 there were 900 feet of underground workings. Capps and Johnson (1915) reported assays of 11.4 to 12.5 % Cu; and 0.18 oz Au and 0.26 oz Ag per ton. Later development included four adits with about 820 ft. of underground workings and some open cuts. Three of the adits are caved or flooded (Jansons and others, 1984). Chip samples from the open cuts contained 0.18% to 8.4% Cu, 170 ppm to 0.25% Zn, and 0.8 ppm to 28 ppm Ag (Jansons and other, 1984); Grab samples gave the following values: 100 ppm to 9.75% Cu, 100 ppm to 1.05% Zn, and 0.8 ppm to 9.5 ppm Ag.

Reference information

Links to other databases

Agency Database name Acronym Record ID Notes
USGS Mineral Resources Data System MRDS A010433
USGS Alaska Resource Data File ARDF CV014

Bibliographic references

  • Deposit

    Capps, S.R., and Johnson, B.L., 1915, The Ellamar district, Alaska: U.S. Geological Survey Bulletin 605, 125 p.

  • Deposit

    Jansons, Uldis, Hoekzema, R.B., Kurtak, J.M., and Fechner, S.A., 1984, Mineral occurrences in the Chugach National Forest, Southcentral Alaska: U.S. Bureau of Mines Open-File Report 5-84, 218 p., 2 sheets, scale 1:250,000.

  • Deposit

    Crowe, D.E., Nelson, S.W., Brown, P.E., Shanks III, W.C., and Valley, J.W., 1992, Geology and geochemistry of volcanogenic massive sulfide deposits and related igneous rocks, Prince William Sound, south-central Alaska: Economic Geology, v. 87, p. 1722-1746.

  • Deposit

    Crowe, D.E., Nelson, S.W., Brown, P.E., Shanks III, W.C., and Valley, J.W., 1993, Geology and geochemistry of volcanogenic massive sulfide deposits and related igneous rocks, Prince William Sound, south-central Alaska-A reply: Economic Geology, v. 88, p. 1285-1288.

  • Deposit

    Sainsbury, C.L., 1993, Geology and geochemistry of volcanogenic massive sulfide deposits and related igneous rocks, Prince William Sound, south-central Alaska, A discussion: Economic Geology, v. 88, p. 1284-1285.

  • Deposit

    Nelson, S.W., Dumoulin, J. A., and Miller, M.L., 1985, Geologic map of the Chugach National Forest, Alaska: U.S. Geological Survey Miscellaneous Field Studies Map MF-1645-B, 16 p., 1 sheet, scale 1:250,000.

  • Deposit

    Cobb, E.H., 1972, Metallic mineral resources map of the Cordova quadrangle, Alaska: U.S. Geological Survey Miscellaneous Field Studies Map MF-392, 1 sheet, scale 1:250,000.

Comments on the references

  • Primary Reference = Jansons and others, 1984

General comments

Subject category Comment text
Deposit Model Name = Cyprus massive sulfide (Cox and Singer, 1986; model 24a)
Deposit Other Comments = Nelson and others (1985) interpret the country rocks as accreted ocean crust. Crowe and others (1992; 1993) and Sainsbury (1993) discuss the genesis of the volcanogenic massive sulfide deposits in this area.? Chugach Alaska Corporation, Anchorage, Alaska has control of these lands.

Reporter information

Type Date Name Affiliation Comment
Reporter 10-JUN-00 S.W. Nelson U.S. Geological Survey