Eagle

Mine, Probably inactive

Alternative names

Ellis
American Eagle

Commodities and mineralogy

Main commodities Au
Other commodities Pb
Ore minerals arsenopyrite; galena; gold; limonite; pyrite
Gangue minerals carbonate minerals; chlorite; quartz; white mica

Geographic location

Quadrangle map, 1:250,000-scale VA
Quadrangle map, 1:63,360-scale B-4
Latitude 61.3157
Longitude -145.4047
Nearby scientific data Find additional scientific data near this location
Location and accuracy This mine is on the east side of the cirque at the head of Boulder Creek (Moffit, 1935, plate 1). The map site is 2.1 miles northwest of Mount Tiekel at an elevation of about 4,500 feet in the SE1/4 section 28, T. 6 S., R. 1 W., of the Copper River Meridian. This mine is probably located to within one-half mile. It is locality 44 of Cobb and Matson (1972) and locality 36 of Winkler and others (1981 [OFR 80-892-B]).

Geologic setting

Geologic description

Oxidized, gold-bearing quartz veins with arsenopyrite and galena cut metaflysch of the Valdez Group at this mine; the metaflysch is locally cut by felsic dikes (Moffit, 1918). The veins, varying from 1 to 6 feet thick, and felsic dikes trend N20W parallel to a prominent joint set. An open cut and adit with about 125 feet of underground workings developed this mine. A small mill was installed in 1918; oxidized ore was amalgamated in an arrastre on site or shipped to the Cliff mine (VA107) for milling. Moffit (1935) estimated that $10,000 to $20,000 worth of gold (500 to 1,000 ounces) were produced.
These veins are probably similar to others that are widespread in the southern Valdez quadrangle. Data summarized by Goldfarb and others (1997) show that gold-bearing quartz veins in the Valdez Group commonly contain pyrite, arsenopyrite, carbonate minerals, chlorite, and white mica and formed from water-rich fluids with 5 to 15 mole percent CO2 and significant amounts of CH4, N2, and H2S. The vein-forming fluid salinities were less than 8 percent, vein formation temperatures ranged from 225 to 375 degrees centigrade, and emplacement depths varied from 3 to 10 kilometers. The vein-forming fluids were produced by metamorphic devolatilization reactions. Radiometric dating indicates that the veins formed from 57 to 49 Ma (Goldfarb and others, 1997, p. 171) when deep parts of the accreted Valdez Group flysch underwent high-grade metamorphism and partial melting (Hudson, 1994).
Geologic map unit (-145.406773251841, 61.3152001637046)
Mineral deposit model Low-sulfide Au-quartz veins (Cox and Singer, 1986; model 36a)
Mineral deposit model number 36a
Age of mineralization Radiometric dating indicates that the gold-bearing quartz veins in the Valdez Group formed from 57 to 49 Ma (Goldfarb and others, 1997, p. 171) when deep parts of the accreted Valdez Group flysch underwent high-grade metamorphism and partial melting (Hudson, 1994).
Alteration of deposit Country rocks to gold-bearing quartz veins in Valdez Group metaflysch can be variably silicified, carbonitized, and sericitized (Goldfarb and others, 1997).

Production and reserves

Workings or exploration An open cut and adit with about 125 feet of underground workings developed this mine. A small mill was installed in 1918; oxidized ore was amalgamated in an arrastre on site or shipped to the Cliff mine (VA107) for milling.
Indication of production Yes; small
Production notes Moffit (1935) estimated that $10,000 to $20,000 worth of gold (500 to 1,000 ounces) were produced.

References