City

Prospect, Active

Alternative names

Golden Range

Commodities and mineralogy

Main commodities Ag; Au
Other commodities As
Ore minerals arsenopyrite; gold; pyrite
Gangue minerals carbonate minerals; quartz; sericite

Geographic location

Quadrangle map, 1:250,000-scale NB
Quadrangle map, 1:63,360-scale D-6
Latitude 62.866
Longitude -143.9511
Nearby scientific data Find additional scientific data near this location
Location and accuracy The City prospect is about 10.8 miles north of Slana. It is about 1.3 mile west-northwest of VABM 6677 'Ahtell' and about 0.5 mile west-northwest of the center of section 32, T. 3 S., R. 8 E., Copper River Meridian. The location is accurate to within 30 feet of the center of the prospect (C. Brown, Alaska Exploration Manager, Corvus Gold, written commun., 2014).

Geologic setting

Geologic description

The rocks in the area of the City prospect are diorite and quartz diorite of the Permian to Pennsylvania Ahtell pluton (Richter, 1966; Richter and others, 1975; Wilson and others, 1998; Corvus Gold Inc., 2012). The rocks are cut by extensive dike swarms and faults. The mineralization is on the northeast side of a regional-scale northwest-striking fault.
The City prospect may have been sampled in 1980 when WGM Inc. on behalf of the Ahtna Native Corporation searched for the source of geochemical anomalies in gold that outlined a northwest-trending area several miles long that WGM had identified in 1979 (WGM Inc., 1979, 1980). In 1980, they collected several rock samples at scattered locations along the trend that contained up to 3,260 parts per billion (ppb) gold.
In 2010, Corvus Gold Inc. revisited the area, outlined an area of mineralization 2 by 9 kilometers in size, and called it the Golden Range target. They collected more than 300 rock and soil samples in the area. The 151 rock samples averaged 0.6 gram of gold per tonne; 29 of the 151 had more than 0.10 gram of gold per tonne, and the best had 50.4 grams of gold per tonne.
By 2011, Corvus had identified at least 5 prospects in the Golden Range target area that they had sampled and drilled (Corvus Gold, Inc., 2012). One is the City prospect where they drilled 3 holes. Notable intercepts were 0.7 metes that averaged 6.21 grams of gold per tonne and 6.68 grams of silver per tonne, and 2.8 meters that averaged 1.57 grams of gold per tonne and 0.38 gram of silver per tonne. Details of the mineralization are unavailable but it is probably similar to that at the nearby Notch prospect (GU045) where arsenopyrite-quartz veins are in a thick mineralized zone marked by sericitic and quartz-carbonate alteration (Meyers and others, 2011).
Geologic map unit (, )
Mineral deposit model Polymetallic vein? (Cox and Singer, 1986; model 22c)
Mineral deposit model number 22c?
Age of mineralization Younger than the Permian to Pennsylvanian host rocks.
Alteration of deposit Extensive silica-carbonate alteration of diorite and quartz diorite? In addition, quartz, sericite, and pyrite (W.T. Ellis, Vice President, Alaska Earth Sciences, Inc., written communication, 2014).

Production and reserves

Workings or exploration The City prospect may have been sampled in 1980 when WGM Inc. on behalf of the Ahtna Native Corporation searched for the source of geochemical anomalies in gold that outlined a northwest-trending area several miles long that WGM had identified in 1979 (WGM Inc., 1979, 1980). In 1980, they collected several rock samples at scattered locations along the trend that contained up to 3,260 parts per billion (ppb) gold. In 2010, Corvus Gold Inc. revisited the area, outlined an area of mineralization 2 by 9 kilometers in size, and called it the Golden Range target. They collected more than 300 rock and soil samples in the area. By 2011, Corvus had identified at least 5 prospects in the Golden Range target area that they had sampled and drilled (Corvus Gold, Inc., 2012). One is the City prospect where they drilled 3 holes.
Indication of production None
Reserve estimates None.
Production notes None.

Additional comments

The 04/01/2012 version of this record incorrectly listed the ARDF number as GU050 for Gulkana quadrangle while the quadrangle abbreviation should be NB as it is located in the Nabesna quadrangle.

References

References

Corvus Gold Inc., 2012, Chisna: http://www.corvusgold.com/projects/alaska/chisna/ (as of March 1, 2012).
Myers, Russell, Brown, Chris, Taylor Christ, Wilkins, Andres, Burnett, Bill, Stroup, Caleb, Keeley Josh, Benchley, Kristen, Robinson, John, Van Wyck Nick, and Jacobs, Joe, 2011, Golden Range- A new high grade gold discovery in Alaska: Alaska Miners Association, 2011 Annual Convention Abstracts, p. 37.
Richter, D.H., Lanphere, M.A., and Matson, N.A., Jr., 1975, Granite plutonism and metamorphism, eastern Alaska Range, Alaska: Geological Society of American Bulletin, v. 86, p. 819-820.
WGM Inc., 1979, 1978 Annual Progress Report, Uranium Exploration, Ahtell Creek Area, Volume I: WGM Inc., 39 p., appendices, 4 maps. (Report available, Ahtna Mineral Co., Anchorage, Alaska).
WGM Inc., 1980, 1979 Summary report of gold potential, Slana District, Ahtna project: WGM Inc., 10 p., map, scale 1:63,360. (Report held by Ahtna Mineral Co., Anchorage, Alaska).
Reporters D.J. Grybeck (Contractor, USGS); V.C. Zinno (Alaska Earth Sciences, Inc.)
Last report date 8/24/2014