Yankee Creek

Mine, Undetermined

Commodities and mineralogy

Main commodities Au
Other commodities Ag
Ore minerals gold

Geographic location

Quadrangle map, 1:250,000-scale OP
Quadrangle map, 1:63,360-scale A-1
Latitude 63.0091
Longitude -156.3652
Nearby scientific data Find additional scientific data near this location
Location and accuracy Yankee Creek is a north-northeast-flowing tributary to the upper Innoko River. Only the lower 4.5 miles of Yankee Creek are in the Ophir quadrangle; the rest of it flows through the Iditarod quadrangle. Mining activity occurred in both quadrangles. The junction of Yankee Creek and the Innoko River is approximately 8 miles southeast of the town of Ophir. The coordinates are for the approximate midpoint of mining activity along Yankee Creek in the Ophir quadrangle; it is near a landing strip and cabins marked on the U.S. Geological Survey Ophir A-1 topographic map (1954, minor revisions 1966), in sec. 3, T. 29 S., R. 13 E., Kateel River Meridian. Yankee Creek corresponds to localities 24 and 25 of Cobb (1972 [MF 367]). This location is accurate.

Geologic setting

Geologic description

The bedrock in the vicinity of Yankee Creek is slate, sandstone, and decomposed igneous rock (Mertie, 1936); the area also contains Cretaceous or Tertiary rhyolitic dikes and alkali-calcic monzonite plutons. These intrusive rocks are the likely source of gold in Yankee Creek (Bundtzen and others, 1987). Only the lower 4 1/2 miles of Yankee Creek are in the Ophir quadrangle; extensive mining along Yankee Creek also occurred in the Iditarod quadrangle.
Gold is found in the coarse gravels; in 1911, these gravels were about 8 feet thick and buried under 1 to 3 feet of muck and silt (Maddren, 1911). Bundtzen and others (1987) report that the gold is 849.6 fine, with 129.5 parts silver, and 20.0 parts impurities. Smith (1941) reports an average gold fineness of 882.
Heavy minerals identified in pan concentrates from lower Yankee Creek include magnetite, ilmenite, magnesiochromite, scheelite, and free gold (Bundtzen and others, 1987). Marten Gulch, a locally-named tributary to Yankee Creek in the Ophir quadrangle, contained magnetite, ilmenite, siderite, hornblende, hypersthene, akermanite, and hidalgoite (a lead- arsenic sulfate) (Bundtzen and others, 1987).
Yankee Creek was first prospected during the winter of 1908-1909, and mining began in 1909 (Maddren, 1910; Maddren, 1911). Mining was nearly continuous from 1910 until 1940 (Cobb, 1976 [OFR 76-576]). Williams (1950) and Saunders (1960) report mining along Yankee Creek in 1950 and 1959.
A conservative estimate of production from Yankee Creek between 1909 to 1968 and 1981 to 1986 is 62,500 ounces of gold and 12,650 ounces of silver (Bundtzen and others, 1987).
Geologic map unit (-156.367560481509, 63.0084685352879)
Mineral deposit model Placer Au (Cox and Singer, 1986; model 39a)
Mineral deposit model number 39a
Age of mineralization Quaternary. The source(s) of the placer gold probably are the Cretaceous or Tertiary rhyolitic dikes and monzonite plutons in the area (Bundtzen and others, 1987).

Production and reserves

Workings or exploration Yankee Creek was first prospected during the winter of 1908-1909, and mining began during 1909 (Maddren, 1910; Maddren, 1911). Mining along Yankee Creek was nearly continuous from 1910 until 1940 (Cobb, 1976 [OFR 76-576]). A dredge was installed in 1921 and operated every year until 1940 (Cobb, 1976 [OFR 76-576]). After 1940, mining was intermittent. Williams (1950) and Saunders (1960) report that Rosander and Reed mined Yankee Creek in 1950 and 1959.
Indication of production Yes; medium
Production notes A conservative estimate of production from Yankee Creek between 1909 to 1968 and 1981 to 1986 is 62,500 ounces of gold and 12,650 ounces of silver (Bundtzen and others, 1987).

Additional comments

Also see the ARDF site for Yankee Creek in the Iditarod quadrangle.

References

MRDS Number A015018

References

Reporters C.E. Cameron
Last report date 8/7/2001