Location: The Ruby Creek placer mine is on lower Ruby Creek, about 0.5 mile from its confluence with Minook Creek. The site is at the mine symbol near the western edge of section 25, T. 7 N., R. 13 W., of the Fairbanks Meridian. The location is accurate. The location corresponds to map number 46 of Cobb (1972), and to Ruby Creek, U.S. Bureau of Land Management MAS number 0020480036.
Geology: Ruby Creek drains an area underlain by Triassic (Rampart Group) argillite and chert, Triassic gabbro, and diverse schists (Mertie, 1934; Chapman and others, 1982; Reifenstuhl and others, 1997 [RI 97-15a]). The placer mine is at the easternmost point of contact between Ruby Creek and the gabbro. The lower portion of the creek is deeply incised, and contains alluvial deposits 300 to 500 feet wide and 5 to 7 feet thick (Mertie, 1934). Mining on Ruby Creek was first reported by Collier (1903). The gold is concentrated on the bedrock surface and is evenly distributed across the entire width of the gravel deposits (Mertie, 1934). The deposits extend a mile and a half upstream from the mouth of Ruby Creek (Hess, 1908). The gold from Ruby Creek is iron-stained and rougher than the gold from Minook (TN054) and Hunter (TN062) creeks (Mertie, 1934). Other heavy minerals in the placer concentrates included garnet, barite, and silver nuggets up to 2 ounces (Cobb, 1973). Burand and Saunders (1966) described native bismuth in a concentrate and also referred to reports of native copper and galena. Ruby Creek contains unfractured, euhedral garnets of possible gem quality (T.K. Bundtzen, oral commun., 2001). Mining in the area was intermittent from 1902 to 1916. Production through the fall of 1904 was worth about $13,500 in gold (Hess, 1908), equivalent to about 650 ounces of gold at $20.67 per ounce. Harry Havrilack mined on Ruby Creek 1/4 mile from the mouth in 1957 and 1962 (Saunders, 1957 [MR 194-17]; Saunders, 1962), and mining was underway in 1967 (Heiner and others, 1968). Harry Havrilack operated a bulldozer on Ruby Creek in 1975 (Carnes, 1976). There is no record of further activity until Bundtzen and others (1992) reported that Williams Mining operated on Ruby Creek in 1991. An auriferous, copper-bearing quartz vein (TN050) 3.5 miles upstream from the Ruby Creek placer deposit yielded an Ar40/Ar39 isotopic age of 61.2 +/- 0.3 Ma (Reifenstuhl and others, 1997 [PDF 97-29h]). Such veins may be the source of some of the placer gold. Hess (1908) speculated that the gold was locally derived from carbonaceous slate containing disseminated pyrite.
Workings: Mining on Ruby Creek was first reported by Collier (1903). The placer workings on Ruby Creek appear to have been surficial. At least one report describes using a hydraulic plant in mining (Brooks, 1907). Harry Havrilack mined on Ruby Creek 1/4 mile from the mouth in 1957 and 1962 (Saunders, 1957 [MR 194-17]; Saunders, 1962), and mining was underway in 1967 (Heiner and others, 1968). Harry Havrilack operated a bulldozer on Ruby Creek in 1975 (Carnes, 1976). In 1991, Williams Mining Company operated on Ruby Creek (Bundtzen and others, 1992).
Age: Quaternary.
Production: Production through the fall of 1904 was worth about $13,500 in gold (Hess, 1908), equivalent to about 650 ounces of gold at $20.67 per ounce.

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

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Commodity List

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Mineral List

5 valid minerals.