Candle Creek Mine, Yukon-Koyukuk Census Area, Alaska, USAi

Regional Level Types
Candle Creek Mine	Mine
Yukon-Koyukuk Census Area	Census Area
Alaska	State
USA	Country

Stream gradient in upper valley is about 60 meters/kilometer.
Location: The Candle Creek placer deposit is located in the valley of Candle Creek, which flows 11 miles (18 km) to Tatalina River, a tributary of Takotna River, which in turn flows into the Kuskokwim River. The placer deposit occupies the upper headward reaches of Candle Creek valley at an elevation ranging from 550 feet (168 m) to 780 feet (238 m) in both NE1/4 and SE1/4 sec. 10, T. 32 N., R. 35 W., of the Seward Meridian. Most placer mining activities took place about 8 miles (13 km) southwest of the village of McGrath. Location is precisely known.
Geology: Deposit consists of placer gold with abundant cinnabar and ilmenite; minor scheelite, monazite, olivine, garnet, and zircon; and trace PGE. Deposits consist of river gravels composed of weathered monzonite, monzodiorite, granite, basalt, andesite, and hornfels, which reflects nearby bedrock sources (Bundtzen and Laird, 1983). The known paystreak was deposited on monzonite and monzo-diorite. The heavy minerals and placer gold found in the Candle Creek placer deposit were derived from quartz veins, and mineralized shears within a silica-saturated phase of the pluton near the faulted western pluton-volcanic contact of the Candle volcanic-plutonic complex (Bundtzen and Laird, 1983; Bundtzen and Miller, 1997). The developed portion of the placer deposit on Candle Creek varies from 45 meters to 200 meters wide and about 2,300 meters long. The pay gravels range from 2 meters to 8 meters thick, with overburden markedly thickening below the northeasterly limits of the mined area. According to T. Almasy (personal communication, 1997) and Holdsworth (1952), the thick overburden and thawed pay gravels prevented further exploitation of the placer deposit by either open cut or underground methods. Churn drilling programs conducted by both the Kuskokwim Dredging Company and Strandberg and Sons Inc. indicates that auriferous-bearing gravels continue for an additional 2 miles (3.2 km) downstream and northeast of the lower limits of the mined paystreak (L. Magnuson, personal communication, 1997; unpublished Strandberg and Sons Inc. data). Placer gold, especially at the upper end of the paystreak, is very coarse and angular; nuggets up to 2 ounces (62 grams) in weight are common, which suggests minimal transport from hardrock sources. Gold fineness varies from 894 to 917 and averages 902 (Bundtzen and others, 1987). The average gold content of gravels mined in previous years was considered rich compared to those mined in creeks elsewhere in the region. For example 23,050 cubic yards (17,620 cubic meters) of gravel mined with open-cut methods between 1915 and 1917 yielded 6,130 ounces (190.6 kg) gold; these gravels contained 0.23 ounces gold per cubic yard. During 1920 to 1923, the Kuskokwim Dredging Company dredged 567,447 cubic yards gravel and produced 68,750 ounces (2,138 kg) gold for an average recoverable grade of 0.12 ounces gold per cubic yard. Bundtzen and others (1987) reported that mined concentrates from Candle Creek contained 5.2 ppm PGE and 11.5 percent chromium (probably from magnesiochromite); however, the PGE source in the concentrates is unknown. Abundant cinnabar was also commercially recovered in addition to the placer gold.
Workings: Early mining from 1915 to 1917 consisted of ground sluicing and hydraulic open-cut methods by the McKinnon-Aitken partnership. From 1918 to 1926, the Kuskokwim Dredging company mined the placer deposits with bucketline stacker dredge technologies (Wimmler, 1922, 1924, 1925, 1926; Moffit, 1927). From 1937 to 1941 and from 1946 to 1947, Strandberg and Sons Inc. mined the Candle Creek placer deposit with a large-scale dragline operation (Roehm, 1937). Strandberg and Sons Inc. restarted the old Kuskokwim Dredging Company dredge and operated it from 1949 to 1952 (Holdsworth, 1952). Small-scale open-cut mine methods have taken place from 1927 to 1936 and from 1995 to 1998. The Kuskokwim Dredging Company and Strandberg and Sons Inc. have conducted extensive churn drilling programs in Candle Creek valley from the 1920s to the 1940s.
Alteration: Pay gravels are partially decomposed by groundwater weathering.
Production: In 1913, Placer gold was discovered in Candle Creek by Louis Blackburn and Bert Eldridge (Bundtzen and Laird, 1983; Brooks, 1914). From 1915 to 1917, the Aitken-McKinnon partnership mined the upper limits of the paystreak with open-cut methods and produced 6,130 ounces (190.6 kg) refined gold from 23,050 cubic yards (17,260 cubic meters) of gravel. In 1916 and 1917, the Kuskokwim Dredging Company (KDC) hauled in and built a 3 cubic foot capacity bucketline stacker dredge on Candle Creek. From 1918 to 1926, the KDC produced 99,158 ounces (3,083 kg) refined gold. During 1920 to 1923, the KDC dredge processed 567,447 cubic yards of pay (433,870 cubic meters) and produced 68,750 ounces (2,138 kg) of refined gold. Volume figures for processed gravels are unknown for the years 1918, 1919, and 1924 to 1926. In addition to placer gold production, approximately 83 flasks (6,308 pounds) of byproduct mercury that were recovered from cinnabar concentrates were produced by KDC from 1921 to 1924, and marketed to local placer mine operators (Bundtzen and Laird, 1983; Mertie and Harrington, 1924; T.K. Bundtzen and Ted Almasy, written communication, 1997). Small scale open-cut placer mining by Carl and Gus Shutler took place on Candle Creek from 1927 to 1936 (Smith, 1929, 1930, 1932, 1933). From 1936 to1941 and from 1946 to 1947, Strandberg and Sons Inc. operated a large-scale dragline-fed mining operation in Candle Creek basin and recovered 17,494 ounces (544 kg) refined gold (Smith, 1937, 1938, 1939, 1941). In 1948 Strandberg and Sons Inc. rebuilt the KDC dredge, which operated from 1949 to 1952 (Holdsworth, 1952). Magnuson Mining Company produced gold from open-cut mine operations from 1995 to 1998. Total known production from placer deposits in Candle Creek basin is 138,377 ounces (4,304 kg) of refined gold, at least 11,963 ounces (372 kg) of byproduct silver, and 83 flasks (6,308 pounds) of byproduct mercury.

Commodities (Major) - Ag, Au, Hg; (Minor) - PGE, W
Development Status: Yes; medium
Deposit Model: Residual, elluvial, and alluvial gold-heavy mineral placer (Cox and Singer, 198

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Link to USGS - Alaska:	MG002

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References