Willow Creek

Mine, Probably inactive

Commodities and mineralogy

Main commodities Ag; Au
Other commodities Cr; Hg; Sn; U; W; Zr
Ore minerals chromite; cinnabar; gold; ilmenite; magnetite
Gangue minerals zircon

Geographic location

Quadrangle map, 1:250,000-scale ID
Quadrangle map, 1:63,360-scale B-5
Latitude 62.37507
Longitude -158.06919
Nearby scientific data Find additional scientific data near this location
Location and accuracy Willow Creek has been placer mined for about 2.5 miles below the mouth of Happy Creek. The coordinates are at the midpoint of the mine which is at the label 'placer mine' on the USGS 1:63,360-scale topographic map. The workings are centered in about the middle of the NW1/4 section 6, T. 26 N., R. 48 W., of the Seward Meridian. The location is accurate. The Willow Creek Mine is locality 24 of Cobb (1972 [MF 363]); also described in Cobb (1976 [OFR 76-576]).

Geologic setting

Geologic description

The Willow Creek Mine is developed on an auriferous pay streak in the valley of modern Willow Creek. It could be the extension of the Happy Creek placer (ID103), although the lower Happy Creek placer is lower grade and the the two deposits may not be continuous (John Fullerton, oral communication, 1986).
The bedrock under most of the Willow Creek placer is shale and sandstone of the Upper Cretaceous. Kuskokwim Group. Willow Creek is aligned along a northeast trending lineament that is interpreted to be a high angle fault. A dike swarm nearly parallel to the fault lends credence to this interpretation (Bundtzen and others, 1988; Bundtzen and others, 1992; Miller and Bundtzen, 1994; Miller, Bundtzen, and Gray, 2005).
The pay streak in Willow Creek starts at the mouth of Happy Creek. The overburden increases from about 12 feet thick at that point to about 25 feet thick at the southwest end of the pay streak (Mertie, 1936; John Fullerton, oral communication, 1986). The principal heavy minerals in concentrates are abundant zircon, cinnabar, magnetite, ilmenite, and chromite (Cobb, 1976 [OFR 76-576]; Bundtzen Cox, and Veach, 1987; Bundtzen and others, 1992). The gold averages 874 fine, the same as the gold on the Willow bench (ID105). The pay zones in Lower Willow Creek were lower grade than either Happy Creek or the Willow bench. The placer deposits on lower Willow Creek are largely mined out. However, the pay streak deepens downstream, suggesting that the cutoff is economic rather than abrupt.
Mineralized gold-bearing stockwork quartz veins in intrusive rocks on Chicken Mountain could be the lode source for the gold and heavy minerals on Willow Creek (Bundtzen and others, 1992). However, there are few monzonite cobbles in the Lower Willow Creek pay streak; this may, however, reflect the considerable distance from distance from Chicken Mountain that would tend to break down the granitic material (Mertie, 1936). The dike swarm exposed at the head of the creek also may be a source of the placer gold in Willow Creek.
Based on examination of published and unpublished records, Bundtzen and others (1992) estimated that Willow Creek and the Willow bench (ID105) produced at least 41,948 ounces of gold and 5,033 ounces of silver, mainly from 1910 to 1986.
Geologic map unit (-158.071596767719, 62.3743843667278)
Mineral deposit model Au placer deposit (Cox and Singer, 1986; model 39a).
Mineral deposit model number 39a
Age of mineralization The Willow Creek placer is probably Quaternary.

Production and reserves

Workings or exploration Gold was discovered on Willow Creek early in the 20th Century, and part of the creek was explored by test pits and drifts in 1910 (Maddren, 1911). An early claimant was Frank G. Manley who also developed placer claims in Flat Creek. A steam-powered dragline began to operate in 1915, the first to be used in the district (Brooks, 1916). Manley worked the claims at intervals into the 1920s. In about 1933, Manley leased the claims to the Iditarod Mining Company of W. E. Dunkle and Pardners Mines of New York who erected a large dragline in 1935, after the creek was redrilled under the supervision of Ben Bromberg. It was necessary to construct a long bedrock drain and to bring water to the field (Hawley, 2003). The project failed in 1936 or 1937 partly because of low-grade gold values and frozen ground. However, the development led to the successful mining of Willow Creek by the Fullerton brothers from the 1960s to the 1980s.
Indication of production Yes
Reserve estimates The placer deposits on lower Willow Creek are largely mined out. However, the paystreak deepens downstream, suggesting that the cutoff is probably economic rather than abrupt.
Production notes Based on examination of published and unpublished records, Bundtzen and others (1992) estimated that Willow Creek and the Willow bench (ID105) produced at least 41,948 ounces of gold and 5,033 ounces of silver, mainly from 1910 to 1986.

References

MRDS Number A015067

References

Hawley, Charles C., 2003, Wesley Earl Dunkle, Alaska's Flying Miner: University of Alaska Press, 380 p.
Reporters T.K. Bundtzen (Pacific Rim Geological Consulting, Inc.), M.L. Miller (U.S. Geological Survey); and C.C. Hawley (Hawley Resource Group)
Last report date 5/24/2003