Eureka Creek (including Boston, Unanimous, Nugget, and American creeks)

Mine, Inactive

Commodities and mineralogy

Main commodities Au
Ore minerals gold

Geographic location

Quadrangle map, 1:250,000-scale TN
Quadrangle map, 1:63,360-scale A-1
Latitude 65.17903
Longitude -150.21856
Nearby scientific data Find additional scientific data near this location
Location and accuracy This site represents an approximately 4-mile-long area of placer mining on Eureka Creek and its tributaries that stretches from the northern half of section 36, T. 5 N., R. 13 W., to the southwest corner of section 16, T. 4 N., R. 13 W., of the Fairbanks Meridian. The site is at the abandoned townsite of Eureka. The site is included in location 40 of Cobb (1972), and roughly corresponds with the U.S. Bureau of Land Management site for Eureka Creek (MAS number 0020480128). Other MAS locations represented by this site are Boston Creek (MAS number 0020480030) and Unanimous-American Creeks (MAS number 0020480049). As of 1952 much of this area was accessible by a light-duty road.

Geologic setting

Geologic description

The bedrock of most of the upper reaches of Eureka Creek, as well as of the area that has been mined, consists of Jurassic or Cretaceous sandstone, siltstone, shale, and quartzite (Chapman and others, 1982; Reifenstuhl and others, 1998). Some of the strata are intruded by several small, northeast-trending Cretaceous monzodiorite plugs. The creek follows a southwest-trending thrust fault for four miles. This fault is manifested by the valley's asymmetry. The southeast side is steep, and consists of quartzite, and the northwest side, along which the placer benches occur, slopes gently. Two benches have been identified, one approximately 250 feet above the present channel and one 50 feet above the channel. Yeend (1990) describes four terraces at Eureka Creek, with the best-developed one 250 feet above the present channel. Yeend (1990) hypothesized that ancestral Eureka and Pioneer creeks flowed southwest toward Tofty during the Pleistocene and joined the ancestral Tanana River farther west than the present day channel. The gradient of Eureka Creek between points 1.5 miles below and 3 miles above Boston Creek is about 100 feet per mile. Above Boston Creek, water supply is small and during an average summer is barely adequate for sluicing.
The discovery of gold on Eureka Creek in 1898 was the first one in the Hot Springs district and it sparked a stampede (Cobb, 1973). Mining on a one-mile stretch, including the discovery claim just below the confluence with Boston Creek, started by 1900 (Collier, 1903), and mining along Eureka Creek was continuous until 1940 (Cobb, 1977). Active claims or workers in 1967 included Boston Boys, Brock and Johnson, Farmer and Jones, Frank & Co., Gill, and Strandberg Mines, Inc. (Heiner and others, 1968).
Both drift mining and open cuts were used. The gravels are 10 to 18 feet thick, and overlain by eight feet of muck. Pay continued for several feet into bedrock (Prindle and Hess, 1905). The width of the pay streaks ranged from 25 to 75 feet. Much of the gold occurred as chunks, commonly attached to vein quartz (Prindle and Hess, 1905; Mertie, 1934). The gold fineness was 780. Hess (1908) described small quartz veins and reported considerable disseminated pyrite in the sheared grit and argillaceous bedrock. According to Hess, the pay contained sticky clay, which made sluicing difficult.
Newberry and Clautice (1997) analyzed a coarse gold nugget intergrown with quartz by electron microprobe. The gold was homogeneous with respect to silver and mercury contents, averaging 20 percent silver, 1.3 percent mercury, and a fineness of 780. The gold composition is similar to that in lode deposits on Elephant Mountain (TN067).
Activity has been reported in recent years on Eureka Creek. John Cole operated a bulldozer on mining claims in 1975 (Carnes, 1976). Shimsky Mining operated along the creek in 1985 (Bundtzen and others, 1986) and reportedly completed assessment work on holdings in 1986. Mark Krenzke placer mined from 1988-1990, the last year of which Orval McCormack also worked Eureka Creek (Green and others, 1989; Bundtzen and others, 1990; Swainbank and others, 1991). James Crude worked the creek in 1989, and Thurman Oil and Mining operated there in 1991 (Bundtzen and others, 1992). Kelly Mining and Ed Salter both worked Eureka Creek (Swainbank and others, 1995) in 1994, and Bob Bettisworth placer mined on the creek in 1996 (Swainbank and others, 1997). BIFS Mining and Eleven Pup Mining both explored for placer gold in 1997 (Swainbank and others, 1998).
From 1968 to 1995, exploration on Boston Creek near its junction with Eureka Creek included bedrock testing, overburden stripping, building a slick plate and sluicebox, and roadwork, but no mining was reported (Alaska Kardex files). Claims were staked in 1977 on Unanimous Creek, a tributary to Eureka Creek, followed in 1979-1981 by test panning and other prospecting (Alaska Kardex files). Claims were staked in 1972 on Nugget Creek, another tributary to Eureka Creek, and on the upper part of Eureka Creek, followed in 1979-1995 by test panning and other prospecting, but no mining was reported (Alaska Kardex files).
It is unclear how much gold has been recovered from Eureka Creek. Hess (1908) reported production of about $85,300 worth of gold (at $20.67 per ounce) as of the fall of 1904, but this figure included some of the production from the Pioneer Creek area. Cobb (1977) reported production in 1916 of 2,900 ounces of gold, and that total production from 1899 to 1940, although unknown, was large.
Geologic map unit (-150.221043263196, 65.1785525252217)
Mineral deposit model Placer Au (Cox and Singer, 1986; model 39a).
Mineral deposit model number 39a
Age of mineralization Quaternary.

Production and reserves

Workings or exploration
The discovery of gold on Eureka Creek in 1898 was the first one in the Hot Springs district and it sparked a stampede (Cobb, 1973). Mining on a one-mile stretch, including the discovery claim just below the confluence with Boston Creek, started by 1900 (Collier, 1903), and mining along Eureka Creek was continuous until 1940 (Cobb, 1977). Active claims or workers in 1967 included Boston Boys, Brock and Johnson, Farmer and Jones, Frank & Co., Gill, and Strandberg Mines, Inc. (Heiner and others, 1968).
Activity has been reported in recent years on Eureka Creek. John Cole operated a bulldozer on mining claims in 1975 (Carnes, 1976). Shimsky Mining operated along the creek in 1985 (Bundtzen and others, 1986) and reportedly completed assessment work on holdings in 1986. Mark Krenzke placer mined from 1988-90, the last year of which Orval McCormack also worked Eureka Creek (Green and others, 1989; Bundtzen and others, 1990; Swainbank and others, 1991). James Crude worked the creek in 1989, and Thurman Oil and Mining operated there in 1991 (Bundtzen and others, 1992). Kelly Mining and Ed Salter both worked Eureka Creek (Swainbank and others, 1995) in 1994, and Bob Bettisworth placer mined on the creek in 1996 (Swainbank and others, 1997). BIFS Mining and Eleven Pup Mining both explored for placer gold in 1997 (Swainbank and others, 1998).
From 1968 to 1995, exploration on Boston Creek near its junction with Eureka Creek included bedrock testing, overburden stripping, building a slick plate and sluicebox, and roadwork, but no mining was reported (Alaska Kardex files). Claims were staked in 1977 on Unanimous Creek, a tributary to Eureka Creek, followed in 1979-1981 by test panning and other prospecting (Alaska Kardex files). Claims were staked in 1972 on Nugget Creek, another tributary to Eureka Creek, and on the upper part of Eureka Creek, followed in 1979-1995 by test panning and other prospecting, but no mining was reported (Alaska Kardex files).
Indication of production Yes; medium
Production notes It is unclear how much gold has been recovered from Eureka Creek. Hess (1908) reported production of about $85,300 worth of gold (at $20.67 per ounce) as of the fall of 1904, but this figure included some of the production from the Pioneer Creek area. Cobb (1977) reported that production in 1916 equaled 2,900 ounces of gold, and that total production from 1899 to 1940, although unknown, was large.

References

MRDS Number A015220

References

Heiner, L.E., Wolff, E.N., and Lu, F.C.J., 1968, Mining regions and mineral commodities, in Heiner, L.E., and Wolff, E.N. eds., Final Report - Mineral Resources of Northern Alaska: Mineral Industry Research Laboratory, University of Alaska Report No. 16, p. 3-137.
Reporters G.E. Graham (ADGGS), D.J. Szumigala (ADGGS)
Last report date 5/8/2004