Spruce Creek Mine, Ruby Mining District, Yukon-Koyukuk Census Area, Alaska, USAi

Regional Level Types
Spruce Creek Mine	Mine
Ruby Mining District	Mining District
Yukon-Koyukuk Census Area	Census Area
Alaska	State
USA	Country

The tailings marked on the Ruby A-5 quadrangle map (1952, minor revisions in 1973) are probably not tailings, but erosion from the water ditch (Jim Johnson, oral communication, 2000).
Location: Spruce Creek is a northeast-flowing tributary of the Sulatna River and is approximately 3 1/2 miles long. Coordinates that correspond to location 28 of Cobb (1972 [MF405]) are given for the approximate midpoint of placer ground, in section 35, T. 15 S., R. 17 E., Kateel River Meridian. Placers extend from below the mouth of Schist Creek to the junction of the creek with the Ruby-Poorman road, a distance of about 3 miles. The location is accurate.
Geology: The bedrock underlying Spruce Creek is slate, schist, and phyllite that have been intruded by rhyolite (Eberlein and others, 1977). The stream gravels are composed of igneous rocks and dark siliceous slates, with considerable clay (Mertie and Harrington, 1916). The pay streak follows the creek and is 55 to 70 feet deep (Mertie and Harrington, 1916). The gravel is 2 to 5 feet thick. The creek was mined for about 3 miles along its length. The gold is close to bedrock, well-rounded, and fine, though nuggets worth $2 to $3 were reported (gold at $20.67 per ounce) (Mertie and Harrington, 1916). Some of the nuggets contain vein quartz. Mineable ground ran from 75 cents per square foot of bedrock to $12 pans (gold at $20.67 per ounce) (Mertie and Harrington, 1916). Amorphous cassiterite is found with the gold, but it was not recovered as a byproduct (Mertie and Harrington, 1924; Eberlein and others, 1977). Some assays of the gold recovered show 854 parts gold per thousand and 140 parts silver per thousand (Mertie, 1936). Prospecting along Spruce Creek began in 1913, and there was nearly continuous mining along the creek until the 1940's ( Brooks, 1914; Eberlein and others, 1977). Intermittent mining took place along Spruce Creek from the 1940's to recent years. Most mining took place along the upper right limit of the creek (Jim Johnson, oral communication, 2000). During the early and mid 1980's, Sphinx America prospected and drilled along Spruce Creek (Jim Johnson, oral communication, 2000).
Workings: Prospecting along Spruce Creek began in 1913, and there was nearly continuous mining along the creek until the 1940's ( Brooks, 1914; Eberlein and others, 1977). Intermittent mining took place along Spruce Creek from the 1940's to recent years. Most mining took place along the upper right limit of the creek (Jim Johnson, oral communication, 2000). During the early and mid 1980's, Sphinx America prospected and drilled along Spruce Creek (Jim Johnson, oral communication, 2000).
Age: Quaternary.
Production: Mineable ground ran from 75 cents per square foot of bedrock to $12 pans (gold at $20.67 per ounce) (Mertie and Harrington, 1916).

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

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Link to USGS - Alaska:	RB058

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References