Spruce Creek

Mine, Active?

Commodities and mineralogy

Main commodities Au
Other commodities Ag
Ore minerals chromite; gold; ilmenite; magnetite

Geographic location

Quadrangle map, 1:250,000-scale OP
Quadrangle map, 1:63,360-scale A-2
Latitude 63.0928
Longitude -156.5264
Nearby scientific data Find additional scientific data near this location
Location and accuracy Spruce Creek is a northeast-flowing tributary to the Innoko River. The junction of Spruce Creek and the Innoko River is approximately 2 miles southeast of the town of Ophir. The coordinates are for the approximate midpoint of tailings shown on the U.S. Geological Survey Ophir A-2 topographic map (1954, minor revisions 1965), in sec. 2, T. 28 S., R. 12 E., Kateel River Meridian. Spruce Creek is locality 17 of Cobb (1972 [MF 367]). This location is accurate. Also see Tamarack Creek (OP027), a small tributary to Spruce Creek.

Geologic setting

Geologic description

The bedrock in the vicinity of Spruce Creek mainly of slate cut by highly altered dacitic (?) dikes (Maddren, 1910; Mertie, 1936). Cretaceous or Tertiary monzonite intrusive bodies may also occur in the stream drainage (Bundtzen and others, 1987).
Most of the gold in Spruce Creek is in bedrock crevices on low benches (Maddren, 1911; Eakin, 1914; Mertie, 1936). The overburden was about 10 to 15 thick over 2 to 6 feet of auriferous gravels (Eakin, 1914). Some of the gold recovered was very coarse, and included at least one 16-ounce nugget was recovered (Mertie, 1936). The gold at Spruce Creek is 870.7 fine, with 100.3 parts silver, and 29.0 parts impurities (Bundtzen and others, 1987). Smith (1941) reports that gold from Spruce Creek averages 879 fine; Metz and Hawkins (1981) report a fineness of 873.
Heavy minerals identified in a pan-concentrate sample from Spruce Creek include magnetite, chromite, ilmenite, orthoferrosilite, riebeckite, and fluorapatite. This sample was collected just downstream from a swarm of peraluminous dikes that contain up to 6% chromite (Bundtzen and others, 1987). The source of the gold is probably these peraluminous dikes, along with some contribution from monzonite intrusions (Bundtzen and others, 1987).
Gold was discovered in Spruce Creek in 1907, but there is no record of production until 1910 (Maddren, 1909; Maddren, 1910; Maddren, 1911). Mining was nearly continuous between 1910 and 1940 (Cobb, 1976 [OFR 76-576]). After 1940, reports of mining along Spruce Creek are sporadic. There probably has been more recent production.
A conservative estimate of production from Spruce Creek from 1909 to 1950 and 1955 to 1986 is 35,400 ounces of gold and 4,600 ounces of silver (Bundtzen and others, 1987).
Also see OP018, 019, 021, 027, and 030.
Geologic map unit (-156.528763916918, 63.0921697763014)
Mineral deposit model Placer Au (on benches) (Cox and Singer, 1986; model 39a)
Mineral deposit model number 39a
Age of mineralization Quaternary. The sources of the placer gold probably are Cretaceous or Tertiary peraluminous dikes, along with some contributions from monzonite intrusive bodies in the Spruce Creek drainage basin (Bundtzen and others, 1987).

Production and reserves

Workings or exploration Gold was discovered in Spruce Creek in 1907, but there is no record of production until 1910 (Maddren, 1909; Maddren, 1910; Maddren, 1911). Mining was nearly continuous between 1910 and 1940 (Cobb, 1976 [OFR 76-576]). After 1940, reports of mining are sporadic. Williams (1950) reports that Matheson and Savage's dragline-dozer-hydraulic operation (Fowler, 1950) on Spruce Creek closed in 1950 due to the son's induction into the army. Assessment work is reported in 1959 (Saunders, 1960). There probably has been more recent production.
Indication of production Yes; small
Production notes A conservative estimate of production from Spruce Creek from 1909 to 1950 and 1955 to 1986 is 35,400 ounces of gold and 4,600 ounces of silver (Bundtzen and others, 1987).

References

MRDS Number A010751; A015014

References

Metz, P.A., and Hawkins, D.B., 1981, A summary of gold fineness values from Alaska placer deposits: University of Alaska, Fairbanks, Mineral Industry Research Laboratory Report No. 45, 56 p.
Reporters C.E. Cameron
Last report date 8/7/2001