Surprise Creek; Summit Creek Mine, Koyukuk Mining District, Yukon-Koyukuk Census Area, Alaska, USAi

Regional Level Types
Surprise Creek; Summit Creek Mine	Mine
Koyukuk Mining District	Mining District
Yukon-Koyukuk Census Area	Census Area
Alaska	State
USA	Country

Location: Surprise Creek (named Summit Creek in reports from the 1930's) flows into the east side of Wild Lake about 0.2 mile north of the mouth of Spring Creek. There is evidence of placer mining activity along a 2-mile stretch of the creek, but the mine workings appear to be concentrated along a 500-foot segment about 0.5 mile above the mouth. This mining is in the NW1/4 section 14, T. 31 N., R 18 W., of the Fairbanks Meridian. The location is accurate.
Geology: Placer gold was discovered in 1904 in the modern stream bed of Surprise (Summit) Creek and mining began that year (Reed, 1938). Surprise Creek was sporadically mined from 1904 through about 1937. Mining has been sporadic and in many cases the workings failed to reach bedrock. Where it was reached, the depth to bedrock is 12 to 14 feet but the bedrock surface apparently dips to the north under talus and its depth becomes progressively greater. The gravel in the creek is not frozen. It is very coarse and angular, and contains many large boulders at the top of the section. The gold is coarse, many nuggets occur with the fine gold. The gold occurs in the lower 3 feet of the gravel and on top of the bedrock; its fineness is about 920. Smith (1932) reported that a boulder of quartz float found in Summit (Surprise) Creek was 'liberally spangled with gold'. Samples collected by Kurtak and others (1999) along Surprise Creek include panned concentrates that contain up to 3,888 ppb gold, limonite-stained quartz-carbonate float that contains 163 ppb gold, and a piece of malachite-stained schist. The rocks in Surprise Creek are described by Reed (1938) as quartzite, greenstone, and graphitic and micaceous schists, cut by several quartz veins in the lower valley. Quartz also constitutes a substantial portion of the detrital material in the creek. Dillon and others (1986) map the area as Middle Devonian siliceous clastic rocks.
Workings: Surprise Creek was sporadically mined from 1904 through about 1937, typically by booming off the fine material, stacking the rocks along the cut, and shoveling-in the lower 3 feet of the the gravel (Reed, 1938).
Age: Quaternary.
Production: There are no production figures available.

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

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Link to USGS - Alaska:	WI009

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References