Bonanza Hills

Prospect, Active

Alternative names

Main Saddle

Commodities and mineralogy

Main commodities Ag; Cu; Pb
Other commodities Au
Ore minerals arsenopyrite; chalcopyrite; galena; tetrahedrite
Gangue minerals quartz

Geographic location

Quadrangle map, 1:250,000-scale LC
Quadrangle map, 1:63,360-scale C-5
Latitude 60.7061
Longitude -154.5956
Nearby scientific data Find additional scientific data near this location
Location and accuracy The Bonanza Hills prospect extends about 1.5 km along a ridge, between peak 3,860 and peak 3,966, in the Bonanza Hills. It is approximately 3.5 km east-southeast of Little (Upper) Bonanza Creek in the SW1/4SW1/4 sec. 6, T. 7 N., R. 30 W., of the Seward Meridian. The location is accurate.

Geologic setting

Geologic description

A quartz-sulfide vein system containing tetrahedrite, arsenopyrite, galena, and chalcopyrite cuts sedimentary rocks and dacite hornfels (Eakins and others, 1978). The mineralization consists of a 3-meter-wide zone of quartz sulfide 'splatter' veinlets that extends at least 150 meters along strike to a depth of 50 meters. Channel samples contain an average of 103 grams of silver per tonne and 0.5 percent combined Cu and Pb. Samples contain up to 2.24 parts per million (ppm) gold.
The contact-metamorphosed dacite flows and sedimentary rocks are part of a Jurassic to Cretaceous unit (KJs) that consists of interbedded lithic graywacke, silty sandstone, black shale , and local conglomerate (Nelson and others, 1983). Irregular quartz segregations and veinlets are locally present. Scattered stocks and locally abundant dikes of intermediate to felsic composition intrude these sedimentary rocks. Contact aureoles of hornfels ring some of the larger igneous bodies which include rhyolite dikes and a Late Cretaceous, two-mica, hypabyssal, granite pluton (Nokleberg and others, 1997).
Liberty Star Uranium and Metals Corporation (2007) has 54 State of Alaska claims covering about 13.5 square miles around this prospect. Twenty samples were collected in their preliminary work; 5 contained 0.001 to 0.006 ounce of gold per ton, 2 contained 0.02 ounce of gold per ton, 1 contained 0.267 ounce of gold per ton, one contained 0.403 ounce of gold per ton, and one contained 3.11 ounces of gold per ton.
Geologic map unit (-154.597857414462, 60.7054242949177)
Mineral deposit model Gold vein system or disseminated gold deposit associated with a composite intrusive center?
Age of mineralization Cretaceous or younger.
Alteration of deposit Unknown.

Production and reserves

Workings or exploration In 2008 within a large block of claims held by Liberty Star Uranium and Metals Corporation who did preliminary sampling.
Indication of production None
Reserve estimates Nokleberg and others (1987; 1997) estimate that the deposit contains 45,000 tonnes of material with a grade of 81 grams of silver per tonne, 0.15 grams of gold per tonne, 0.15 percent copper, and 0.067 percent lead.
Production notes No production.

References

MRDS Number A013008

References

Liberty Star Uranium and Metals Corp., 2007, Bonanza Hills project: http://www.libertystaruranium.com/sub.asp?sub_id=35&section_id=8 (as of March 4, 2008).
Reporters M.L. Miller (USGS); D.P. Bickerstaff (USGS); D.J. Grybeck (Port Ludlow, WA)
Last report date 3/4/2008