American Creek; Teddys Fork; Discovery Fork; Alder Gulch Mines, Eagle District, Southeast Fairbanks Borough, Alaska, USA

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Location: American Creek is a 20-mile-long tributary of Mission Creek, whose mouth is near Eagle. American Creek has two major branches, Teddys Fork and Discovery Fork, but most reports refer to Teddy's Fork simply as American Creek. The coordinates are where most placer mining occurred, near the junction of Discovery Fork, Teddys Fork, and American Creek, in section 4, T. 3 S., R. 32 E., of the Fairbanks Meridian. The location is accurate. This record combines the references to Teddys Fork, Discovery Fork, and Alder Gulch (a small tributary of Teddys Fork that is not labeled on the U.S. Geological Survey topographic map of the Eagle C-1 quadrangle (1956; revised in 1973). American Creek is localities 35, 37 and 38 of Cobb (1972 [MF-393]), locality 2 of Eberlein and others (1977), and localities 18, 19, and 21 of Burleigh and Lear (1994).
Geology: The rocks along upper American Creek are Paleozoic quartz-mica schist, greenschist, marble, and greenstone and Paleozoic or Mesozoic serpentinite (Foster, 1976). Bedrock on lower American Creek is Paleozoic or Mesozoic serpentinite, Cretaceous to Tertiary nonmarine sedimentary rocks, and Paleozoic greenstone, quartzite, and argillite. Extensive Quaternary terrace deposits occur near the mouth of the creek. Most placer gold mining occurred near the junction of Discovery Fork with American Creek, an area commonly referred to as the Forks. Placer mining also occurred on lower American Creek within 5 miles of the mouth, but little or no work was done in the intervening stretch. Placers of the lower valley are interpreted to have a secondary source in the Cretaceous to Tertiary clastic sedimentary rocks (Mertie, 1938). Gravel in the lower valley is 15 to 40 feet thick, and coarse gold was recovered (Powers, 1935). Most placer gold from American Creek was recovered near the Forks. The average depth of overburden in this area was about 14 feet. The valley is about 30 yards wide, and gravels averaged about 65 cents to the square foot of bedrock in 1936 (gold at $35.00 per ounce) (Mertie, 1938). One cut just below the Forks exposed 12 feet of gravel. Gold was fairly coarse and included several large nuggets. Fineness of the gold at this site was not determined, but it sold for about $28 per ounce (gold at $35 an ounce) (Mertie, 1938). There is also a poorly defined bench about 1 mile north of the Forks, about 15 feet above the creek. The gravel here is about 5 feet thick and consists of 3 feet of loose gravel and 2 feet of clay-rich gravel. Gold is found throughout the lower half of this gravel, but the best pay is next to bedrock and within the upper 2 feet of bedrock (Prindle, 1905). Much of the gold is coarse. Placer gold has also been recovered on Discovery Fork and its tributary Star Gulch. The depth to bedrock on the lower part of Discovery Fork is about 7 to 9 feet; the gold lies on and in bedrock. A 19-ounce nugget was recovered from Discovery Fork, but most of the gold was in smaller particles (Mertie, 1938). Near the upper part of Discovery Fork, the gravel is 5 to 7 feet thick. The gold is coarser than that found downstream. Alder Gulch, a small tributary to American Creek, was mined out in a period of a few years. Rich pay was found in gravels from the mouth of Alder Gulch for about one-half mile upstream (Powers, 1935). Gold was also mined from Gravel Gulch in the early 1900's, but the location of this stream is uncertain (Foster and Keith, 1969). The average fineness of 10 samples of placer gold from the upper part of American Creek and its tributaries was 865 parts of gold and 130 parts of silver per thousand (Mertie, 1942). Smith (1941 [B 910-C]) reported assays of 5 gold samples from American Creek. The fineness of one sample was 902, and the other four samples fell between 858 and 898 parts of gold per thousand. A nugget recovered in 1899 was valued at $192 (gold at $20.67 per ounce) (Brooks, 1900); it must have weighed about 11 ounces (Mertie, 1938). Placer concentrates contain abundant magnetite and barite, as well as some monazite. American Creek placers also contain platinum (Burleigh and Lear, 1994). Gold-bearing quartz veins in bedrock were reported near the head of American Creek (Spurr, 1898), but their location is unknown. Placer gold on American Creek was discovered around 1891, and the stream has been mined intermittently since 1896. Placer gold was being actively mined in the late 1800's and early to middle 1900's, and American Creek and its tributary Discovery Fork were considered the most important gold-mining area in the vicinity of Eagle in 1905 (Prindle, 1905). The discovery claim on American Creek is located at the mouth of Discovery Fork and serves as the reference point for numbering claims on both forks (Mertie, 1938). In 1903 and 1904, miners used a hydraulic plant approximately 1 mile above the confluence of Discovery Fork, and an automatic water dump gate was installed on Discovery Fork (Brooks, 1905; Prindle, 1905). The 1912 season was considered profitable; the gravel over about 17,000 square feet of bedrock on American Creek and over about 11,000 square feet of bedrock on Discovery Fork were processed by shoveling dirt into sluice boxes (Ellsworth and Davenport, 1913). A nugget worth $80 was found at this time (gold at $20.67 per ounce) (Ellsworth and Davenport, 1913). American Creek, Discovery Fork, and Star Gulch were still being mined for placer gold in 1936 (Mertie, 1938), and mining continued until at least 1940. The lower end of Teddys Fork was being mined for placer gold in the late 1970's (Eberlein and others, 1977). Bulldozers, backhoes and sluice plants were used in later years to process the gravels. Small-scale placer mining on American Creek continues in the 1990's (Swainbank and others, 1993). The first 15 years of mining on American Creek and its tributaries produced a considerable amount of gold (Powers, 1935). In 1896, one placer mine returned $27 per day per man (Spurr, 1898). Prindle (1905) estimated that as of 1905 about $20,000 worth of gold had been produced from Discovery Fork.
Workings: Placer gold on American Creek was discovered around 1891, and the stream has been mined intermittently since 1896. Placer gold was being actively mined in the late 1800's and early to middle 1900's, and American Creek and its tributary Discovery Fork were considered the most important gold-mining area in the vicinity of Eagle in 1905 (Prindle, 1905). The discovery claim on American Creek is located at the mouth of Discovery Fork and serves as the reference point for numbering claims on both forks (Mertie, 1938). In 1903 and 1904, miners used a hydraulic plant (Prindle, 1905) approximately 1 mile above the confluence of Discovery Fork, and an automatic water dump gate was installed on Discovery Fork (Brooks, 1905). The 1912 season was considered profitable; the gravel overlying about 17,000 square feet of bedrock on American Creek and over about 11,000 square feet of bedrock on Discovery Fork were processed by shoveling dirt into sluice boxes (gold at $20.67 per ounce) (Ellsworth and Davenport, 1913). American Creek, Discovery Fork, and Star Gulch were still being mined for placer gold in 1936 (Mertie, 1938), and mining continued until at least 1940. The lower end of Teddys Fork was being mined for placer gold in the late 1970's (Eberlein and others, 1977). Bulldozers, backhoes and sluice plants were used in later years to process the gravels. Small-scale placer mining on American Creek continues in the 1990's (Swainbank and others, 1993).
Age: Quaternary.
Production: The first 15 years of mining on American Creek and its tributaries produced a considerable amount of gold (Powers, 1935). In 1896, one placer mine returned $27 per day per man (Spurr, 1898). Prindle (1905) estimated that as of 1905 about $20,000 worth of gold had been produced from Discovery Fork.

Commodities (Major) - Au; (Minor) - Pt, REE
Development Status: Yes; medium
Deposit Model: Placer Au (Cox and Singer, 1986; model 39a).

References

Brooks, A.H., 1900, A reconnaissance from Pyramid Harbor to Eagle City, Alaska, including a description of the copper deposits of the upper White and Tanana Rivers: U.S. Geological Survey Twenty-first Annual Report, p. 331-391, plate 2. Brooks, A.H., 1903, Placer gold mining in Alaska in 1902: U.S. Geological Survey Bulletin 213, p. 41-48. Brooks, A.H., 1904, Placer mining in Alaska in 1903: U.S. Geological Survey Bulletin 225, p. 43-59. Brooks, A.H., 1905, Placer mining in Alaska in 1904: U.S. Geological Survey Bulletin 259, p. 18-31. Brooks, A.H., 1907, The Alaskan mining industry in 1906: U.S. Geological Survey Bulletin 314-A, p. 19-39. Brooks, A.H., 1909, The mining industry in 1908: U.S. Geological Survey Bulletin 379-A, p. 21-62. Brooks, A.H., 1915, Mineral resources of Alaska; report on progress of investigations in 1914: U.S. Geological Survey Bulletin 622, 380 p. Brooks, A.H., 1916, Mineral resources of Alaska, report on progress of investigations in 1915: U.S. Geological Survey Bulletin 642, 279 p. Bundtzen, T.K., Swainbank, R.C., Deagen, J.R., Moore, J.L., 1990, Alaska's Mineral Industry 1989: Alaska Division of Geological & Geophysical Surveys, Special Report 44, 100 p. Burleigh, R.E., and Lear, K.G., 1994, Compilation of data for Phase I of the mineral resource evaluation of the Bureau of Land Management Black River and Fortymile subunits: U.S. Bureau of Mines Open-File Report 48-94, 116 p. Clark, S.H.B., and Foster, H.L., 1971, Geochemical and geological reconnaissance in the Seventymile River area, Alaska: U.S. Geological Survey Bulletin 1315, 21 p. Cobb, E.H., 1972, Metallic mineral resources map of the Eagle quadrangle, Alaska: U.S. Geological Survey Miscellaneous Field Studies Map MF-393, 1:250,000 scale, 1 sheet. Cobb, E.H., 1977, Summary of references to mineral occurrences in the Eagle quadrangle, Alaska: U.S. Geological Survey Open-File Report 77-845, 122 p. Eberlein, G.D., Chapman, R.M., Foster, H.L., and Gassaway, J.S., 1977, Map and table describing known metalliferous and selected nonmetalliferous mineral deposits in central Alaska: U.S. Geological Survey Open-File Report 77-168-D, 132 p., 1 sheet, scale 1:1,000,000. Ellsworth, C.E., 1910, Placer mining in the Yukon-Tanana region: U.S. Geological Survey Bulletin 442-F, p. 230-245. Ellsworth, C.E., and Davenport, R.W., 1913, Placer mining in the Yukon-Tanana region: U.S. Geological Survey Bulletin 542-F, p. 203-222. Ellsworth, C.E., and Parker, G.L., 1911, Placer mining in the Yukon-Tanana region: U.S. Geological Survey Bulletin 480-F, p. 173-217. Foster, H.L., 1976, Geologic map of the Eagle quadrangle, Alaska: U.S. Geological Survey Miscellaneous Investigations Series, Map 922, 1 sheet, scale 1:250,000. Foster, H.L., and Keith, T.E.C., 1969, Geology along the Taylor Highway, Alaska: U.S. Geological Survey Bulletin 1281, 36 p. Koschmann, A.H., and Bergendahl, M.H., 1968, Principal gold producing districts of the United States: U.S. Geological Survey Professional Paper 610, 283 p. Martin, G.C., 1919, Alaska Mining Industry in 1917: U.S. Geological Survey Bulletin 692-A, p. 11-42. Mertie, J.B., Jr., 1930, Mining in the Fortymile district: U.S. Geological Survey Bulletin 813-C, p. 125-142. Mertie, J.B., Jr., 1938, Gold placers of the Fortymile, Eagle, and Circle districts, Alaska: U.S. Geological Survey Bulletin 897-C, p. 133-261. Mertie, J.B., Jr., 1942, Tertiary deposits of the Eagle-Circle district, Alaska: U.S. Geological Survey Bulletin 917-D, p. 213-264. Mertie, J.B., Jr., 1969, Economic geology of platinum minerals: U.S. Geological Survey Professional Paper 630, 120 p. Porter, E.A., 1912, Placer mining in the Fortymile, Eagle, and Seventymile River districts: U.S. Geological Survey Bulletin 520-G, p. 211-218. Powers, J.B., 1935, Brief history of the Fortymile and Eagle Mining Districts to 1935: Alaska Territorial Department of Mines Mineral Report MR 60-2, 19 p. Prindle, L.M., 1905, The gold placers of the Fortymile, Birch Creek, and Fairbanks regions, Alaska: U.S. Geological Survey Bulletin 251, 89 p. Prindle, L.M., 1906, Yukon placer fields: U.S. Geological Survey Bulletin 284, p. 109-127. Prindle, L.M., 1909, The Fortymile quadrangle, Yukon-Tanana region, Alaska: U.S. Geological Survey Bulletin 375, 52 p. Purington, C.W., 1905, Methods and costs of gravel and placer mining in Alaska: U.S. Geological Survey Bulletin 263, 273 p. Saunders, R.H., 1966, A geochemical investigation along the Taylor Highway, east central Alaska: Alaska Division of Mines and Minerals Geochemical Report 9, 17 p. Smith, P.S., 1926, Mineral industry of Alaska in 1924: U.S. Geological Survey Bulletin 783-A, p. 1-30. Smith, P.S., 1929, Mineral industry of Alaska in 1926: U.S. Geological Survey Bulletin 797, p. 1-50. Smith, P.S., 1930, Mineral industry of Alaska in 1927: U.S. Geological Survey Bulletin 810-A, p. 1-64. Smith, P.S., 1930, Mineral industry of Alaska in 1928: U.S. Geological Survey Bulletin 813-A, p. 1-72. Smith, P.S., 1932, Mineral industry of Alaska in 1929, in Smith, P.S., and others Mineral resources of Alaska, report on progress of investigations in 1929: U.S. Geological Survey Bulletin 824-A, p. 1-81. Smith, P.S., 1933, Mineral industry of Alaska in 1930: U.S. Geological Survey Bulletin 836-A, p. 1-83. Smith, P.S., 1933, Mineral industry of Alaska in 1931: U.S. Geological Survey Bulletin 844-A, p. 1-81. Smith, P.S., 1934, Past placer production from Alaska: U.S. Geological Survey Bulletin 857-B, p. 93-98. Smith, P.S., 1934, Mineral industry of Alaska in 1933: U.S. Geological Survey Bulletin 864-A, p. 1-94. Smith, P.S., 1936, Mineral industry of Alaska in 1934: U.S. Geological Survey Bulletin 868-A, p. 1-91. Smith, P.S., 1937, Mineral industry of Alaska in 1935: U.S. Geological Survey Bulletin 880-A, p. 1-95. Smith, P.S., 1938, Mineral industry of Alaska in 1936: U.S. Geological Survey Bulletin 897-A, p. 1-107. Smith, P.S., 1939, Mineral industry of Alaska in 1937: U.S. Geological Survey Bulletin 910-A, p. 1-113. Smith, P.S., 1939, Mineral industry of Alaska in 1938: U.S. Geological Survey Bulletin 917-A, p. 1-113. Smith, P.S., 1941, Fineness of gold from Alaska placers: U.S. Geological Survey Bulletin 910-C, p. 147-269. Smith, P.S., 1941, Mineral industry of Alaska in 1939: U.S. Geological Survey Bulletin 926-A, p. 1-106. Smith, P.S., 1942, Mineral industry of Alaska in 1940: U.S. Geological Survey Bulletin 933-A, p. 1-102. Spurr, J.E., 1898, Geology of the Yukon gold district, Alaska, with an introductory chapter on the history and conditions of the district to 1897 by H.B. Goodrich: U.S. Geological Survey 18th Annual Report, Part 3, p. 87-392. Swainbank, R.C., Bundtzen, T.K., Clough, A.H., Hansen, E.W., and Nelson, M.G., 1993, Alaska's mineral industry, 1992: Alaska Division of Geological and Geophysical Surveys Special Report 47, 80 p. Wedow, Helmuth, Jr., 1954, Reconnaissance for radioactive deposits in the Eagle-Nation area, east-central Alaska, 1948: U.S. Geological Survey Circular 316, 9 p.

Mineral List

Gold

'Monazite'

Platinum

3 entries listed. 2 valid minerals.