Jolly Green

Prospect, Active

Alternative names

Golden Range

Commodities and mineralogy

Main commodities Ag; Au; Cu
Other commodities Fe
Ore minerals chalcopyrite; gold; molybdenite; silver
Gangue minerals quartz

Geographic location

Quadrangle map, 1:250,000-scale GU
Quadrangle map, 1:63,360-scale D-1
Latitude 62.9171
Longitude -144.0975
Nearby scientific data Find additional scientific data near this location
Location and accuracy The Jolly Green prospect is about 15.1 miles north-northwest of Slana. It is about 6.0 miles northwest of VABM 6677 'Ahtell' and about 0.4 mile south of the center of section 9, T. 13 N., R. 7 E., of the Copper River Meridian; near peak 6020. The location is accurate within 1/4 mile.

Geologic setting

Geologic description

The rocks in the area of the Jolly Green 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., 2012a). 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 Jolly Green 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 rock samples 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 specific prospects in the Golden Range target area that they had sampled and drilled (Corvus Gold, Inc., 2012a). One is the Jolly Green prospect where they only collected rock samples; 10 of which they considered significant. Those samples contained 3.0 to 126.5 grams of gold per tonne, 25.7 to 198.0 grams of silver per tonne, and 0.4 to 17.7 percent copper. Little information is available about the mineralization other than they note it has base metals and may reflect a copper-gold porphyry at depth.
The Jolly Green mineralization may be related to that at the unnamed prospect about 1.3 miles to the southeast (GU037), where chalcopyrite and molybdenite commonly occur along joint surfaces in silica-carbonate rock, which is widely developed near the western contact of a pluton.
In 2011, Corvus performed a soil x-ray fluorescence (XRF) survey, which indicated high grade mineralization hosted in north-northwest trending shear zones/quartz vein-breccias. Pervasive fracture-controlled copper oxide coating in quartz-diorite forms supergene halos around shears. High-grade gold is constrained to Jolly Green shear zone. The Jolly Green shear zone hosts over 1 percent copper on 700 meters of strike (Brown and others, 2012).
Geologic map unit (-144.099711877728, 62.9167121146235)
Mineral deposit model Porphyry Cu-Au? (Cox and Singer, 1986; model 20c)
Mineral deposit model number 20c?
Age of mineralization Younger than the Permian to Pennsylvanian host rocks (Wilson and others, 1998).
Alteration of deposit Copper-oxide in supergene halos around shears. High grade copper + gold + silver + molybdenum in shear/quartz-vein breccia zones (Brown and others, 2012).

Production and reserves

Workings or exploration
The Jolly Green 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.
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 specific prospects in the Golden Range target area that they had sampled and drilled (Corvus Gold, Inc., 2012a). One is the Jolly Green prospect where they only collected rock samples.
In 2010 and 2011, Corvus performed a soil survey at Jolly Green of over 12 km in length and average over 10 grams of gold per ton over 12 kilometers with over 50 grams of gold per ton widespread. In 2011, Corvus performed a soil x-ray fluorescence (XRF) survey, which indicated high grade mineralization hosted in north-northwest trending shear zones/quartz vein-breccias. Pervasive fracture-controlled copper oxide coating in quartz-diorite forms supergene halos around shears. High-grade gold is constrained to Jolly Green shear zone. The Jolly Green shear zone hosts over 1 percent copper on 700 meters of strike (Brown and others, 2012). 2011 drilling highlights are 126.5 grams of gold per ton, 198 grams of silver per ton and 17.7 percent copper (Corvus Gold Inc., 2012b).
Indication of production None
Reserve estimates None.
Production notes None.

References

References

Corvus Gold Inc., 2012a, Chisna: http://www.corvusgold.com/projects/alaska/chisna/ (as of March 1, 2012).
Myers, Russell, Brown, Chris, Taylor Chris, 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 12/8/2014