Luna

Prospect, Active

Commodities and mineralogy

Main commodities Ag; Au; Cu
Other commodities As; Bi; Mo; Sb; Sn; Te
Ore minerals arsenopyrite; chalcopyrite; pyrite; sphalerite; stibnite
Gangue minerals carbonate; quartz

Geographic location

Quadrangle map, 1:250,000-scale BH
Quadrangle map, 1:63,360-scale B-2
Latitude 60.4379
Longitude -159.4851
Nearby scientific data Find additional scientific data near this location
Location and accuracy The Luna prospect is located along the North Fork of the Kisaralik River approximately 2 miles downstream of North Fork Lakes in the central-west area of section 14, T. 4 N., R. 59 W. of the Seward Meridian. The location is centered on an outcrop that returned a rock chip sample containing 64.7 grams per tonne gold (Southern Crown Resources Limited, 2014a). The previous recorded location incorrectly put the Luna prospect 3.6 miles northwest of the outlet of the Kisaralik River on Kisaralik Lake.

Geologic setting

Geologic description

Mineralization at the Luna prospect is in Cretaceous calcareous siltstone, shale, sandstone, argillite, conglomerate, tuff and tuffaceous chert that are intruded by Late Cretaceous to Early Tertiary quartz monzodiorite, granodiorite, and biotite granite stocks and aplite dikes (Box and others, 1993).
The Luna prospect is located along a northeast structural corridor with apparent strike slip movement and evidence of additional cross-cutting complexity. A shear zone over 700 meters wide has been mapped along the river beds underneath alluvial cover (Southern Crown Resources Limited, 2014a). Results from a ground geophysical survey completed in 2014 show a very clear northeast trending structure, the Luna Fault, with the Luna prospect located on a structural splay (Southern Crown Resources Limited, 2014b). Channel and auger drill samples show anomalous metal values following the northeast trend next to the Luna Fault with bismuth being the best pathfinder element (Southern Crown Resources Limited, 2014c).
Quartz-carbonate stockwork veins contain anomalous gold, silver, antimony, bismuth, arsenic, molybdenum, tellurium, and tin. The northeast end of the mineralized trend (Luna East) contains highly anomalous copper (Southern Crown Resources Limited, 2014a). Several zones of stratiform, replacement mineralization were found that contain up to 70 percent sulfides, primarily pyrite, arsenopyrite and stibnite, with lesser chalcopyrite and sphalerite. More than half of the 72 rock samples that were collected before 2014 contained anomalous gold. Several of the airborne geophysical anomalies correspond to the location of the semi-massive sulfides on the ground. The mineralization is accompanied widespread fracturing and clay alteration (Gold Crest Mines Inc., 2011).
Geologic map unit (-159.464052907826, 60.3594644892755)
Mineral deposit model Polymetallic veins (Cox and Singer, 1986; model 22c).
Mineral deposit model number 22c
Age of mineralization Late Cretaceous or younger based on the age of the host rocks and intrusions (Box and others, 1993).
Alteration of deposit Mineralization is accompanied by widespread clay alteration (Gold Crest Mines Inc., 2011).

Production and reserves

Workings or exploration
The Luna prospect was discovered in 2006 by Gold Crest Mines Inc. while field checking an airborne geophysical survey. Further field work that year included ground induced polarization and magnetic surveys and rock and stream-sediment sampling. The stream sediment sampling outlined an area of 10 square miles with anomalous values in gold, arsenic, and antimony. Rock samples contained up to 0.75 ounce per ton gold, 8,400 parts per million (ppm) arsenic, 158 ppm antimony, 36 ppm bismuth, 64 ppm molybdenum, 23 ppm silver, 0.44 percent copper, 12 percent lead, and 0.6 percent zinc. In 2007, 50 State of Alaska mining claims were staked that covered an area of about 8,000 acres.
In 2014 Southern Crown Resources Limited began exploration at Luna through an option with Afranex Gold Limited (Southern Crown Resources Limited, 2014a). Results from a ground geophysical survey completed in 2014 show a very clear northeast trending structure, the Luna Fault, with the Luna prospect located on a structural splay (Southern Crown Resources Limited, 2014b). Channel and auger drill samples show anomalous metal values following the 1.3 kilometer northeast trend next to the Luna Fault. Channel samples returned up to 1480 part per billion (ppb) gold with anomalous silver, antimony, bismuth and arsenic while auger drilling returned rock samples with up to 140 ppb gold and 1200 ppb silver. Vegetation samples were also collected over 3 kilometers of the Luna trend with 350 samples taken to look at biogeochemistry which generally correlated well with the rock sample geochemistry (Southern Crown Resources Limited, 2014c).
Indication of production None

References

References

Reporters D.J. Grybeck (Contractor, USGS); N.V. King (Alaska Earth Sciences)
Last report date 2/25/2016