Ophir Creek Mines, Innoko Mining District, Yukon-Koyukuk Census Area, Alaska, USAi

Regional Level Types
Ophir Creek Mines	Group of Mines
Innoko Mining District	Mining District
Yukon-Koyukuk Census Area	Census Area
Alaska	State
USA	Country

Location: Ophir Creek has been mined for about 2 1/2 miles above its mouth, near the town of Ophir on the Innoko River. Mining also took place near its head. The coordinates are for the approximate midpoint of mine tailings marked on the U.S. Geological Survey Ophir A-2 topographic map (1954, minor revisions 1965). This point is on lower Ophir Creek, in sec. 26, T. 27 S., R. 12 E., Kateel River Meridian. Ophir Creek corresponds to localities 13 and 14 of Cobb (1972 [MF 367]). The location is accurate.
Geology: Bedrock in the vicinity of Ophir Creek consists of shale and siltstone (Chapman and others, 1985). The creek also drains small monzonite intrusive bodies, and igneous rock pebbles and cobbles are reported in the stream gravels (Mertie, 1936). Some vein quartz is also reported in the gravels (Mertie, 1936). Most of the gold on Ophir Creek is in crevices in the top 2 to 5 feet of bedrock (Maddren, 1910). The gold is coarse with many nuggets. It also occurs in bench and stream gravels (Maddren, 1910; Maddren, 1911). In 1933, one claim on Ophir Creek averaged $7 to 8 per square foot of bedrock. Nuggets as large as 14 ounces have been recovered (Mertie, 1936). The gold averages 898 fine (Smith, 1941). Heavy minerals in pan concentrates include magnetite, ilmenite, edenite, zircon, rutile, orthoferrosilite, and pyrite (Bundtzen and others, 1987). The likely source of the gold is nearby rhyolite dikes and monzonite plutons (Bundtzen and others, 1987). Gold was discovered on Ophir Creek in 1908, and mining occurred nearly continuously until 1940 (Cobb, 1976 [OFR 76-576]). In 1950, at least one person was mining along Ophir Creek (Williams, 1950). Mining is also reported during 1959, but the operator at that time planned to move to the Ruby district in 1960 (Saunders, 1960). More recent exploration or mining is probable but not documented. The estimated production from Ophir Creek from 1908 to1961 is 66,489 ounces of gold and 7,004 ounces of silver. Production figures for more recent mining from 1978 to 1985 are unknown (Bundtzen and others, 1987).
Workings: Gold was discovered on Ophir Creek in 1908, and mining occurred nearly continuously until 1940 (Cobb, 1976 [OFR 76-576]). By 1914, the creek was one of the chief gold-producing streams in the area, and 8 mines were operating (Eakin, 1914; Brooks, 1915). Drifting, draglines, and hydraulicking were all used to recover the gold. In 1950, at least one person was mining along Ophir Creek (Williams, 1950). Mining is also reported during 1959, but the operator at that time planned to move to the Ruby district in 1960 (Saunders, 1960). More recent exploration or mining is probable but not documented.
Age: Quaternary. The likely source of placer gold at Ophir Creek is nearby Cretaceous or Tertiary rhyolite dikes and monzonite plutons (Bundtzen and others, 1987).
Production: The estimated production from Ophir Creek from 1908 to1961 is 66,489 ounces of gold and 7,004 ounces of silver. Production figures for more recent mining from 1978 to 1985 are unknown (Bundtzen and others, 1987).

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

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Link to USGS - Alaska:	OP030

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References