Eldorado Creek Mine (tributary of Colorado Creek), Innoko Mining District, Yukon-Koyukuk Census Area, Alaska, USAi

Regional Level Types
Eldorado Creek Mine (tributary of Colorado Creek)	Mine
Innoko Mining District	Mining District
Yukon-Koyukuk Census Area	Census Area
Alaska	State
USA	Country

For more information on Eldorado Creek, contact Ron Rosander in McGrath, AK.
Location: Eldorado Creek is a short, generally north-flowing headwater tributary to Colorado Creek. Placer mining on Eldorado Creek was an extension of mining on Colorado Creek. Placer tailings begin at the mouth of Eldorado Creek and continue for nearly 1 mile upstream. The coordinates are for the approximate midpoint of the lower group of tailings, in the southern half of sec. 29, T. 22 S., R. 15 E., Kateel River Meridian. The location is accurate.
Geology: The rocks in the vicinity of Eldorado Creek consist of intermediate to mafic volcanic and volcaniclastic rocks, and of Cretaceous Kuskokwim Group black shale, limestone, graywacke, and conglomerate intruded by Cripple Mountain monzonite (McGinnis, 1997; Avalon Development Corp., 1998; Duncan, 1999). The rocks adjacent to the monzonite are hornfelsed, with local development of garnet- and magnetite-bearing skarn in calcareous volcanic and sedimentary rocks (Avalon Development Corp., 1998; S. Dashevsky, oral commun., 2001). Extensive placer mining was carried out along El Dorado Creek for about one mile upstream from its junction with Colorado Creek. Tailings in the upper part of Eldorado Creek do not follow the modern streambed and extend to the western walls of the stream drainage up to the flanks of Porphyry Knob (OP031) (S. Dashevsky, oral commun., 2001). Placer mining on Eldorado Creek was conducted by the Strandberg family in the 1950's and by Mr. Nerod in the 1970's (McGinnis, 1997). Production figures for Eldorado Creek are not available (see OP002; and in the Medfra quadrangle, MD014, for Colorado Creek drainage production figures). Also see OP002, 031, and 032; and in the Medfra quadrangle, MD014.
Workings: Prior to World War II, placer mining was conducted by William Critchley along the lower portion of Eldorado Creek, and William (Billy the Greek) Senatikis mined the upper portion (Ron Rosander, oral commun., 2001). The Strandberg family mined on Eldorado Creek in the 1950's and Mr. Nerod mined in the 1970's (McGinnis, 1997). During 1994, 1995, and 1996, claimholder Ron Rosander contracted geologist James Barker to evaluate the lode sources of placer gold in the Colorado Creek area. Barker collected 254 soil samples, 93 rock samples, and 12 samples of placer gold for scanning-electron microscope and trace element analysis. Geologic mapping and a ground-based magnetometer survey were also carried out (Barker, 1996; McGinnis, 1997). In 1996, the Alaska Division of Geological and Geophysical Surveys conducted geologic mapping in the Cripple Creek Mountains and Placer Dome Exploration flew an east-west-oriented aeromagnetic survey over the Cripple Creek Mountains. Nova Gold conducted geologic mapping, rock sampling, and soil sampling during the summer of 1998 (Avalon Development, 1998). During 1999, Poseidon Minerals, Ltd. carried out soil sampling in the Colorado Creek area, and used mobile-metallic-ion (MMI) analyses (Duncan, 1999).
Age: Placer deposits along nearby Colorado Creek area are middle Pleistocene, based on isotopic dates from overburden and geological inference (Bundtzen and others, 1987; Thorson and Guthrie, 1992). The skarn deposits are Cretaceous or younger.
Alteration: Rocks adjacent to the monzonite are hornfelsed, with local development of garnet- and magnetite-bearing skarn in calcareous volcanic and sedimentary rocks (Avalon Development Corp., 1998; S. Dashevsky, 2001, oral commun.).

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

Other Databases

Link to USGS - Alaska:	OP033

Other Regions, Features and Areas containing this locality

References