Valdez

Mine, Inactive

Commodities and mineralogy

Main commodities Ag; Cu
Ore minerals bornite; chalcocite; chalcopyrite; covellite; pyrite
Gangue minerals calcite; dolomite

Geographic location

Quadrangle map, 1:250,000-scale MC
Quadrangle map, 1:63,360-scale C-8
Latitude 61.6452
Longitude -143.716
Nearby scientific data Find additional scientific data near this location
Location and accuracy This mine is on the northeast valley wall of Nugget Creek. It is at an elevation of about 3,700 feet, 1,200 feet upslope of USLM No. 15, and about 1,800 feet southwest of elevation 4660. The location of the mine is shown on the McCarthy C-8 quadrangle (1995 edition) in the NE1/4 of section 2, T. 3 S., R. 9 E. of the Copper River Meridian. This is locality 139 of MacKevett (1976) and locality 18 of MacKevett and others (1978). It is accurately located. Cobb and MacKevett (1980) included this mine under the name 'Nugget Cr.'.

Geologic setting

Geologic description

The deposit at this mine consists of discontinuous dolomite and calcite veins and lenses up to several feet thick that contain bornite, chalcopyrite, pyrite, and a little chalcocite and covellite (Moffit and Mertie, 1923; Van Alstine and Black, 1946). The veins and lenses are localized in a fault zone that cuts Triassic Nikolai Greenstone (Moffit and Mertie, 1923; MacKevett, 1976). A sample of the mineralization contained 200 parts per million silver and more than 2 percent copper (MacKevett, 1976). The deposits were explored and developed over 420 vertical feet by 4,000 feet of underground workings including adits, drifts, crosscuts, winzes, and shafts (Moffit and Mertie, 1923, fig. 7). A mill was located at the mine. Two carloads of high-grade, hand-sorted ore were shipped before 1916 and 160 tons of concentrate and hand-sorted ore were shipped between 1916 and 1919.
The widespread deposition of copper in Triassic greenstone and limestone in the area is thought to have accompanied regional deformation and low-grade metamorphism in the Late Jurassic or Early Cretaceous (MacKevett and others, 1997). Copper-bearing minerals were deposited in the underlying Nikolai Greenstone at about 112 Ma (Silberman and others, 1980).
Geologic map unit (-143.718088308923, 61.644743110164)
Mineral deposit model Basaltic Cu (Cox and Singer, 1986; model 23)
Mineral deposit model number 23
Age of mineralization Cretaceous? The widespread deposition of copper in Triassic greenstone and limestone in the area is thought to have accompanied regional deformation and low-grade metamorphism in the Late Jurassic or Early Cretaceous (MacKevett and others, 1997). Copper-bearing minerals were deposited in the underlying Nikolai Greenstone at about 112 Ma (Silberman and others, 1980).

Production and reserves

Workings or exploration The deposits were explored and developed over 420 vertical feet by 4,000 feet of underground workings including adits, drifts, crosscuts, winzes, and shafts (Moffit and Mertie, 1923, fig. 7). A mill was located at the mine.
Indication of production Yes; small
Production notes Two carloads of high-grade, hand-sorted ore were shipped before 1916 and 160 tons of concentrate and hand-sorted ore were shipped between 1916 and 1919.

Additional comments

The locality is in the Wrangell-Saint Elias National Park and Preserve.

References

MRDS Number A011740

References

Reporters Travis L. Hudson (Applied Geology, Inc.)
Last report date 1/12/2003