Caribou Creek Mine, Fairbanks Mining District, Fairbanks North Star Borough, Alaska, USAi

Regional Level Types
Caribou Creek Mine	Mine
Fairbanks Mining District	Mining District
Fairbanks North Star Borough	Borough
Alaska	State
USA	Country

Location: Caribou Creek drains south to southwest into the Salcha River. The creek is roughly 6 miles long and has several small tributaries. Mining occurred on the lower 4.5 miles of the creek. The approximate center of the mining activity is in NE1/4NW1/4 section 3, T. 3 S., R. 10 E., of the Fairbanks Meridian. Several trails and a landing strip provide access to the Caribou Creek drainage. It is locality 16 of Cobb and Eberlein (1980), who summarized relevant references under the name 'Caribou Creek'.
Geology: The bedrock in the region comprises schist, gneiss, some granite, and minor amounts of serpentinite and marble. The schist is composed of quartz, feldspar, and mica, with localized garnetiferous and marble zones. The gneiss is coarse to fine grained with various amounts of quartz, feldspar, hornblende, and biotite. The schist and gneiss have suspected protoliths of Precambrian and Paleozoic sedimentary and igneous rocks. The intrusive bodies in the area range in composition from granodiorite to quartz monzonite, and have Cretaceous to Tertiary K-Ar ages (Weber and others, 1978). The gravels in the region average 18 to 20 feet in thickness and contain a variety of schist, gneiss, granite, and vein quartz (Prindle, 1906; B 284). Brooks (1908) reported the fineness of the gold in the area to be higher than that mined in the Richardson district. It is reported that coarse gold, native bismuth, and minor scheelite were found in quartz veins in the Caribou Creek drainage (Menzie and Foster, 1979). Joesting (1942) noted the occurrence of scheelite and cassiterite in stream concentrates. Hasler and others (1973) report igneous and metamorphic-hosted quartz veins containing variable amounts of native bismuth, bismuthinite, gold, graphite, and scheelite at an unknown location in the Caribou Creek drainage. Nuggets of native bismuth, up to 3 inches in diameter were found during placer mining (D.L. Grybeck, oral communication, 1999). Glover (1950) reported a range in gold fineness of 884 to 899 for Caribou Creek. Placer gold was first discovered in the area in 1905. Prospecting initially occurred on Butte Creek (BD006) and expanded to Caribou Creek, and Gold Run Creek (BD016) and associated tributaries. Live water and thawed ground presented the biggest obstacles during prospecting (Prindle, 1906). Initially, only a few holes were sunk to bedrock in gravel deposits 24 to 36 feet thick (Prindle, 1906; B 284). In 1909, Caribou Creek became a major producer in the Salcha-Tenderfoot area. Due to thawed ground, drift mining proved difficult. As a result, machinery for ditching and open-cut methods was installed (Ellsworth, 1910). Smith (1939; B 910-A) reports that drilling programs were carried out in 1937 to justify the installation of a dredge equipped with 6-cubic-foot buckets. Additional drilling and evaluation was continued in 1938 and 1939 (Smith, 1941). A dredge was installed in the 1940's and worked most of the stream length (Eberlein and others, 1977). The dredge is still located approximately 4.5 miles up the stream bed (M.B. Werdon, oral communication, 1998). Historically, Caribou Creek has been grouped with the mines and prospects of the Richardson district. From 1905 through 1921, production from the Richardson district was approximately 95,000 ounces of gold and 24,000 ounces of silver (Bundtzen and Reger, 1977). Since 1980, the district has produced approximately 10,000 additional ounces of gold from intermittent mining (Olson and others, 1985). Individual gold production for Caribou Creek has not been reported separately. Exploration to determine the lode source for the placer gold is currently (1998) being conducted in the Caribou Creek drainage (R. Van Nieuwenhuyse, oral communication, 1998).
Workings: Placer gold was first discovered in the area in 1905. Prospecting initially occurred on Butte Creek (BD006) and expanded to nearby Caribou Creek (BD008), and Gold Run Creek (BD016) and associated tributaries. Live water and thawed ground presented the biggest obstacles during prospecting (Prindle, 1906). Initially, only a few holes were sunk to bedrock in gravel deposits ranging from 24 to 36 feet thick (Prindle, 1906; B 284). In 1909, Caribou Creek became a major producer in the Salcha-Tenderfoot area. Due to thawed ground, drift mining proved difficult. As a result, machinery for ditching and open-cut methods was installed (Ellsworth, 1910). Smith (1939; B 910-A) reports that drilling programs were carried out in 1937 to justify the installation of a dredge equipped with 6-cubic-foot buckets. Additional drilling and evaluation was continued in 1938 and 1939 (Smith, 1941). The dredge was installed in the 1940's and worked most of the stream length (Eberlein and others, 1977). The gold dredging operation was completed in 1952 (Saunders, 1954). The dredge is still located approximately 4.5 miles up the stream bed (M. Werdon, oral communication, 1998). Exploration to determine the lode source for the placer gold is currently (1998) being conducted in the Caribou Creek drainage (R. Van Nieuwenhuyse, oral communication, 1998).
Age: Quaternary
Production: Historically, Caribou Creek has been grouped with the mines and prospects of the Richardson area. From 1905 through 1921, production for the Richardson area was approximately 95,000 ounces of gold and 24,000 ounces of silver (Bundtzen and Reger, 1977). Since 1980, the district has produced approximately 10,000 additional ounces of gold from intermittent mining (Olson and others, 1985). Individual gold production for Caribou Creek has not been reported separately.

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

Other Databases

Link to USGS - Alaska:	BD009

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References