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Dowry Creek

Producer in Alaska, United States with commodity Gold
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Geologic information

Identification information

Deposit ID 10308862
MRDS ID A013208
Record type Site
Current site name Dowry Creek
Related records 10258497, 10002302

Geographic coordinates

Geographic coordinates: -161.71268, 58.94925 (WGS84)
Relative position Dowry Creek is a west tributary to upper Salmon River. It flows eastward from headwaters on the northeast flank of the Red Mountain ultramafic pluton. The road from Platinum to Goodnews Mining Camp crosses Dowry Creek very near its confluence with Salmon River. The map site is the approximate center of placer mine workings along the creek. This is locality 11 of Cobb (1972 [MF 362]; 1980 [OF 80-909]).
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Geographic areas

Country State
United States Alaska

Commodities

Commodity Importance
Gold Secondary

Materials information

Materials Type of material
Chromite Ore
Gold Ore
Ilmenite Ore
Magnetite Ore
Sperrylite Ore
Irarsite Ore
Iridarsenite Ore
Osmium Ore
Tulameenite Ore
Xingzhongite Ore

Mineral occurrence model information

Model code 120
USGS model code 39b
BC deposit profile C01. C02
Deposit model name Placer PGE-Au

Nearby scientific data

(1) -161.71268, 58.94925
ListMap

Comments on the geologic information

  • Geologic Description = Dowry Creek, a west tributary to upper Salmon River, flows eastward from headwaters on the northeast flank of the Red Mountain ultramafic pluton. It has been placer mined over about 0.6 miles of its one-mile length, from its confluence with the Salmon River upstream to an elevation of 450 feet. Platinum on Dowry Creek was probably discovered in 1928, the year it was discovered on nearby Clara Creek (HG010). At least some mining occurred in 1935 and a dragline, first installed on Clara Creek in 1935, was probably moved to Dowry Creek and worked the paysteak out by 1941. Bedrock in Dowry Creek is mostly dunite of the Red Mountain ultramafic pluton. Dowry Creek contained about 5 feet of gravel and about 90,000 cubic yards were placer mined. The mean of 5 analyses of Pt-rich samples from Dowry Creek, recomputed free of impurities, is 87.56% Pt, 7.34% Ir, 1.47% Os, 0.12% Ru, 1.25% Rh, 0.46% Pd, and 1.80% Au (Mertie, 1976). Serpentinized dunite at the head of the creek is overlain by a 120-foot-wide and 2-foot-thick unmined deposit of cobbles, boulders, and clay that contains 0.0215 ounce of PGM and 0.0006 ounce of Au per cubic yard (Fechner, 1988, p. 73). Gold particle fineness measurements were 738 and 828. A sample of 3 feet of bank material at an elevation of 600 feet contained 0.0035 ounce of PGM per cubic yard, and two samples of placer mine tailings contained 0.0007 and 0.0015 ounce of PGM per cubic yard (Fechner, 1988, p. 73). Microprobe analyses of platinum-rich grains showed 0.8 to 1.5 percent Rh, 0.4 to 0.9 percent Ru, 63.4 to 80.2 percent Pt, 7.2 to 18 percent Ir, 1.2 to 6.8 percent Os, and 6.6 to 7.5 percent Fe. The grains consisted of iron-platinum alloy containing 8 to 30 percent Fe; iron-platinum alloy with minor osmiridium inclusions; and osmiridium, hollingsworthite, osmium, xingzhongite, iridarsenite, irarsite, sperrylite, and tulameenite.
  • Age = Quaternary.

Economic information

Economic information about the deposit and operations

Development status Producer

Comments on exploration

  • Status = Active?

Mining district

District name Goodnews Bay

Comments on the reserve resource information

  • Reserves = An unmined alluvial deposit in the upper part of the creek is estimated to contain 7,000 cubic yards of material containing 0.0125 ounce of PGM per cubic yard (Fechner, 1988, p. 74).

Comments on the workings information

  • Workings / Exploration = Platinum on Dowry Creek was probably discovered in 1928, the year it was discovered on nearby Clara Creek (HG010). At least some mining occurred in 1935 and a dragline, first installed on Clara Creek in 1935, was probably moved to Dowry Creek and worked the paysteak out by 1941. It has been placer mined over about 0.6 mile of its one-mile length, from its confluence with the Salmon River upstream to an elevation of 450 feet.

Reference information

Links to other databases

Agency Database name Acronym Record ID Notes
USGS Alaska Resource Data File ARDF HG011
USGS Mineral Resources Data System MRDS A013208
USGS Mineral Resources Data System MRDS M045380

Bibliographic references

  • Deposit

    Mertie, J.B., Jr., 1976, Platinum deposits in the Goodnews Bay district, Alaska: U.S. Geological Survey Professional Paper 938, 42 p.

  • Deposit

    Cobb, E.H., 1980, Summaries of data and lists of references to metallic and selected nonmetallic mineral deposits in fifteen quadrangles in southwestern and west-central Alaska: U.S. Geological Survey Open-File Report 80-909, 103 p.

  • Deposit

    Fechner, S.A., 1988, Bureau of Mines mineral investigation of the Goodnews Bay mining district, Alaska: U.S. Bureau of Mines Open-File Report 1-88, 230 p.

  • Deposit

    Cobb, E.H., 1972, Metallic mineral resources map of the Hagemeister Island quadrangle, Alaska: U.S. Geological Survey Miscellaneous Field Studies Map MF-362, 1 sheet, scale 1:250,000.

Comments on the references

  • Primary Reference = Fechner, 1988

General comments

Subject category Comment text
Deposit Model Name = Placer PGE-Au (Cox and Singer, 1986; model 39b)

Reporter information

Type Date Name Affiliation Comment
Reporter 18-MAR-2001 Travis L. Hudson Applied Geology