Latitude: 65°28'11"N
Longitude: 145°17'52"W
Mastodon Creek has produced more gold than any other creek in the Circle district and in its early history was known as the 'best creek in Alaska' (Dunham, 1898). See also Mammoth Creek, ARDF no. CI036, Independence Creek, ARDF no. CI029 and Miller Creek, ARDF no. CI039.
Location: The location is the intersection of Mastodon Creek and Baker Gulch. The placered area extends approximately 2 miles up and downstream, along Mastodon Creek. Mastodon Creek has its headwaters on the northeast flank of Mastodon Dome. It flows in a northeasterly direction for approximately 9.5 km before joining Independence Creek. Below this junction the creek is known as Mammoth Creek. The eastern headwater tributary of Mastodon Creek is known as Forty-Two Gulch. Baker Gulch, about 2.5 km downstream, is the only other tributary of Mastodon Creek.
Geology: Bedrock of the Mastodon Creek drainage is mostly the Middle Schist and Quartzite unit described by Wiltse and others (1995) as quartz-muscovite schist, porphyroblastic-albite-quartz-chlorite-muscovite schist, with lesser amounts of quartzose porphyroblastic albite-chlorite schist. Gold is in the basal 6 feet of unfrozen gravel, on bedrock, and in the top 7 feet of bedrock. Average depth to bedrock is 10 to 12 feet (Prindle, 1913, p. 63). Both the stream and bench gravels are auriferous. The paystreak is the richest in the district and is 200 feet wide and 7 to 10 feet thick. Gold is coarsest near the head of the stream and contains abundant quartz. Downstream the gold becomes more flaky, carries less quartz and shows an increase in fineness (.740 to .811 Au) (Mertie, 1938). Cassisterite is reported in concentrates (Cobb, 1973, [B 1374]). The gravel in Mastodon Creek is coarse and consists mainly of boulders with diameters of 10 to 30 cm, but some boulders are as much as 1 m across. Clasts are commonly subangular to rounded (Yeend, 1991, p. 13). Mining on Mastodon Creek has been nearly continous since gold was discovered. In the early 1900's, most operations consisted of 'shoveling in' gravel to an elevated sluicebox with wood riffles. A steam hoist and a hydraulic plant with a steam scraper were also used (Brooks, 1907). A dredge operated in 1912 to 1913, 1915, and 1918 to 1926. Hydraulic mining was the most favored method on Mastodon Creek for most of its history. In 1937, a dragline excavator began to be used. Baker Gulch was heavily prospected by trenching and panning in 1988 (Yeend, 1991). Production for Mastodon Creek through 1936 was between 96,758 and 145,137 fine ounces (Cobb, 1976, p. 43 to 45, [OFR 76-633]). The early mining operations recovered 0.1 to 0.15 ounces per cubic yard of gravel, whereas by the 1930's, 0.01 to 0.0125 ounces per cubic yard was a common yield (Yeend, 1991). Mastodon Creek produced an estimated 150,000 to 200,000 ounces of gold (Yeend, 1991). In 1987, an operation in the upper creek valley had to discontinue mining because the gold values were only 0.005 ounces per cubic yard (Yeend, 1991).
Workings: Mining on Mastodon Creek has been nearly continous since gold was discovered there in the late 1800's. In the early 1900's, most operations consisted of 'shoveling in' gravel to an elevated sluicebox with wood riffles. A steam hoist and a hydraulic plant with a steam scraper were also used (Brooks, 1907). A dredge operated in 1912 to 1913, 1915, and 1918 to 1926. Hydraulic mining was the most favored method on Mastodon Creek for most of its history. In 1937, a dragline excavator began to be used. Baker Gulch was heavily prospected by trenching and panning in 1988 (Yeend, 1991).
Production: Production for Mastodon Creek through 1936 was between 96,758 and 145,137 fine ounces (Cobb, 1976, p. 43 to 45, [OFR 76-633]). The early mining operations recovered 0.1 to 0.15 ounces per cubic yard of gravel, whereas by the 1930's, 0.01 to 0.0125 ounces per cubic yard was a common yield (Yeend, 1991). Mastodon Creek produced an estimated 150,000 to 200,000 ounces of gold (Yeend, 1991). In 1987, an operation in the upper creek valley had to discontinue mining because the gold values were only 0.005 ounces per cubic yard (Yeend, 1991).
Commodities (Major) - Au; (Minor) - Sn
Development Status: Yes; small
Deposit Model: Placer gold deposit (Cox and Singer, 1986; model 39a)
References
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., 1908, The mining industry in 1907: U.S. Geological Survey Bulletin 345-A, p. 30-53. Brooks, A.H., 1909, The mining industry in 1908: U.S. Geological Survey Bulletin 379-A, p. 21-62. Brooks, A.H., 1914, Mineral resources of Alaska; report on progress of investigations in 1913: U.S. Geological Survey Bulletin 592, 413 p. 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, The Alaskan mining industry in 1915: U.S. Geological Survey Bulletin 642, p. 16-71. Brooks, A.H., 1918, Mineral resources of Alaska, 1916: U.S. Geological Survey Bulletin 662, 469 p. Brooks, A.H., 1923, The Alaska mining industry in 1921: U.S. Geological Survey Bulletin 739-A, p. 1-50. Brooks, A.H., 1925, Alaska's mineral resources and production, 1923: U.S. Geological Survey Bulletin 773-A, p. 3-52. Brooks, A.H., and Capps, S.R., 1924, The Alaska mining industry in 1922: U.S. Geological Survey Bulletin 755-A, p. 1-56. Brooks, A.H., and Martin, G. C., 1921, The Alaska mining industry in 1919: U.S. Geological Survey Bulletin 714-A, p. 59-95. Burand, W.M., 1965, A geochemical investigation between Chatanika and Circle hot springs, Alaska: Alaska Division of Mines and Minerals Geochemical Report 5, 11 p. Burand, W. M., 1968, Geochemical investigations of selected areas in the Yukon-Tanana region of Alaska, 1965 and 1966: Alaska Division of Mines and Minerals Geochemical Report 13, 51 p. Chapin, Theodore, 1914, Placer mining in the Yukon-Tanana region: U.S. Geological Survey Bulletin 592-J, p. 357-362. Cobb, E.H., 1972, Metallic mineral resources map of the Circle quadrangle, Alaska: U.S. Geological Survey Miscellaneous Field Studies Map MF-391, 1 sheet, scale 1:250,000. Cobb, E.H., 1973, Placer deposits of Alaska: U.S. Geological Survey Bulletin 1374, 213 p. Cobb, E.H., 1976, Summary of references to mineral occurrences (other than mineral fuels and construction materials) in the Circle quadrangle, Alaska: U.S. Geological Survey Open-File Report 76-633, 72 p. Ellsworth, C.E., 1910, Placer mining in the Yukon-Tanana region: U.S. Geological Survey Bulletin 442-F, p. 230-245. Ellsworth, C.E., 1912, Placer mining in the Fairbanks and Circle Disctricts: U.S. Geological Survey Bulletin 520-H, p. 240-245. 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 Davenport, R.W., 1915, Surface water supply of the Yukon-Tanana region: U.S. Geological Survey Water-Supply Paper 342, 343 p. 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. Joesting, H.R., 1942, Strategic mineral occurences in interior Alaska: Alaska Territorial Department of Mines Pamphlet 1, 46 p. Johnson, B.L., 1910, Occurrence of wolframite and cassiterite in the gold placers of Deadwood Creek, Birch Creek district: U.S. Geological Survey Bulletin 442-F, p. 246-250. 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. Martin, G.C., 1921, Preliminary report on petroleum in Alaska: U.S. Geological Survey Bulletin 719, 83 p. Menzie, W.D., Foster, H.L., Tripp, R.B., and Yeend, W.E., 1983, Mineral resource assessment of the Circle quadrangle, Alaska: U.S. Geological Survey Open-File Report 83-170-B, 61 p., 1 sheet, 1:250,000. Mertie, J.B., Jr., 1932, Mining in the Circle district: U.S. Geological Survey Bulletin 824-D, p. 155-172. 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. Moffit, F.H., 1927, Mineral industry in Alaska in 1925: U.S. Geological Survey Bulletin 792-A, p. 1-39. Nelson, A.E., West, W.S., and Matsko, J.J., (1952) 1954, Reconnaissance for radioactive deposits in eastern Alaska: U.S. Geological Survey Circular 348, 21 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., 1906, The Yukon-Tanana region, Alaska; Description of Circle quadrangle: U.S. Geological Survey Bulletin 295, 27 p. Prindle, L.M., 1913, A geologic reconnaissance of the Circle quadrangle, Alaska: U.S. Geological Survey Bulletin 538, 82 p. Purington, C.W., 1905, Methods and costs of gravel and placer mining in Alaska: U.S. Geological Survey Bulletin 263, 273 p. Smith, P.S., 1917, The mining industry in the territory of Alaska during the calendar year 1916: U.S. Bureau of Mines Bulletin 153, 89 p. Smith, P.S., 1930, Mineral industry of Alaska in 1927: U.S. Geological Survey Bulletin 810-A, p. 1-64. 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., 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, Mineral industry of Alaska in 1932: U.S. Geological Survey Bulletin 857-A, p. 1-91. 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, 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. Yeend, W.E., 1991, Gold placers of the Circle district, Alaska--Past, present, and future: U.S. Geological Survey Bulletin 1943, 42 p.
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