SW Sun

Prospect, Active?

Commodities and mineralogy

Geographic location

Quadrangle map, 1:250,000-scale SP
Quadrangle map, 1:63,360-scale A-5
Latitude 67.066
Longitude -155.052
Nearby scientific data Find additional scientific data near this location
Location and accuracy This prospect is located 9.6 miles south of Akurekvik Pass, in NE1/4NW1/4 of section 12, T. 19 N., R. 17 E., of the Kateel River Meridian. This location is accurate to within 500 feet.

Geologic setting

Geologic description

Southwest (SW) Sun was discovered in 1974 by the discovery of gossan by Sunshine Mining Company. The SW Sun prospect is characterized by volcanogenic massive-sulfide mineralization. The property is located at the eastern end of the Ambler district. The deposit is comprised of multiple individual lenses that are spatially related; two primary horizons of massive-sulfide mineralization have been identified. The massive sulfides are comprised primarily of sphalerite, tennantite, galena, chalcopyrite, bornite, enargite, pyrite, pyrrhotite, and arsenopyrite. Based on drilling, the SW deposit is currently known to be comprised of two thin massive-sulfide horizons, with the lower one again being less continuous (Gustin and Ronning, 2013).
SW Sun, approximately 2,888 feet southwest of Main Sun (SP039), was thought for a long time to be the offset extension of Main Sun. However, drilling to the west of the Tour Ridge Fault has not confirmed this relationship. Southwest Sun may be a separate hydrothermal center, based on the lack of physical connection to Main Sun and on the presence of talc alteration in the footwall rocks (Gustin and Ronning, 2013).
Mineralization occurs in a northeast-trending belt of felsic metavolcanic and metasedimentary rocks generally dipping 30 degrees to 45 degrees southeast and extending about 13 kilometers from Beaver Creek on the west to Picnic Creek on the east. The volcanic rock package is up to 1.5 kilometers thick and is both overlain and underlain by quartz-chlorite-mica schist. Known massive-sulfide mineralization is limited to the upper portion of the felsic volcanic rocks. Almost all of the mineralization lies beneath glacial cover, with exposures at only three locations (Marrs, 1978).
Massive-sulfide mineralization at the SW Sun is primarily hosted within the felsic schist (Dsf) and sparsely porphyritic rhyolite (Dr) units of the Ambler Sequence. At Sun, the Ambler Sequence is comprised almost entirely of lithologies found in the sequence elsewhere in the district, with the notable exception of the distinctive rhyolite porphyry (Dbs), which is rare elsewhere (although this unit does occur in the Beaver Creek Valley 9.6 kilometers to the west of Sun). Volcanic rocks constitute about 84 percent of the Ambler Sequence at SW Sun. The deposit lies on the north limb of an overturned syncline (Gustin and Ronning, 2013).
Mineralization occurs near a local thickening in the felsic to andesitic volcanic and volcaniclastic rocks of the Ambler Sequence, where the sequence is dissected by the Jewel Creek drainage. The mineralized portion of the Ambler Sequence has been mapped for 5,800 meters along strike and varies in thickness from 750 to 1,500 meters. Significant thicknesses of mineralization have been traced by drilling including across some 2,700 meters including Picnic Creek, Main Sun, and SW Sun (Gustin and Ronning, 2013).
Geologic map unit (, )
Mineral deposit model Kuroko massive sulfide (Cox and Singer, 1986; model 28a)
Mineral deposit model number 28a
Age of mineralization Devonian, based on age of host rock (Gustin and Ronning, 2013).
Alteration of deposit Talc alteration is present in footwall rocks (Gustin and Ronning, 2013).

Production and reserves

Workings or exploration
Diamond core drilling was completed by the Ambler Mining Company between 1975-1981. At SW Sun two sulfide horizons totaling 3.2 meters (10.5 feet) were encountered in drillhole Sun 14 while three horizons totaling up to 7.3 meters (24.8 feet) were encountered in drillholes Sun 28 and Sun 29 to the southwest. The uppermost horizon in the three holes comprised: 0.8 meter (2.5 feet) of 2.73 percent copper, 3.15 percent lead, 6.60 percent zinc, and 265.3 grams of silver per tonne in Sun 14; 6.2 meters (20.4 feet) of 0.10 percent copper, 3.04 percent lead, 5.96 percent zinc and 190.8 grams of silver per tonne in Sun 28; and 1.3 meters (4.2 feet) of 1.83 percent copper, 0.29 percent lead, 4.16 percent zinc and 20.3 grams of silver per tonne in Sun 29 (Gustin and Ronning, 2013).
Recent work by Andover Mining Corp. in 2007 and 2008 includes about 800 soil samples focused mostly on SW Sun. The initial and follow-up soil sampling program identified base-metal anomalies extending for three kilometers to the west of the SW Sun mineralized zone, along the southern edge of the felsic rock package (Gustin and Ronning, 2013).
In 2011, Andover Mining Corp. drilled three exploration holes at SW Sun; all encountered volcanogenic massive sulfide mineralization, and thereby extended the mineralized intersections by a strike length of 0.5 kilometer (Gustin and Ronning, 2013).
Indication of production None
Reserve estimates
A National Instrument 43-101, prepared by Mine Development Associates of Reno, Nevada for Andover Mining Corp., provided the first NI 43-101-compliant mineral resource estimate for Sun and SW Sun. The report was completed on September 30, 2013 (Gustin and Ronning, 2013).
Using a cut-off of $75 per tonne in-ground value, the combined Main Sun and Southwest Sun deposits indicated resources are estimated to total 2,165,000 tonnes (2,387,000 tons) at 1.42 percent copper, 1.06 percent lead, 4.11 percent zinc, 57.6 grams of silver per tonne and 0.21 gram of gold per tonne (3.9 percent copper equivalent). The inferred resources are 11,648,000 tonnes (12.84 million tons) at 1.14 percent copper, 1.37 percent lead and 3.91 percent zinc, 76.8 grams of silver per tonne and 0.24 gram of gold per tonne (3.9 percent copper equivalent). This resource estimation indicates a minimum deposit size as the Main Sun remains open to the northeast and down dip and the Southwest Sun remains open to the southwest and down dip. The copper equivalent grades were calculated based on metal prices of $3 per pound copper, 95 cents per pound lead, 95 cents per pound zinc, $25 per ounce silver and $1,300 per ounce gold, and assume 100 percent recoveries (Gustin and Ronning, 2013).
The resource estimation utilized the database of 97 drill holes totaling 19,123 meters. Andover Mining Corp. has drilled 48 of the holes, totaling 10,311 meters. The remainder are historic drill holes drilled by previous operators, including Cominco (Teck Resources), Anaconda, Sunshine, Noranda and Bear Creek (Kennecott) (Gustin and Ronning, 2013).
Production notes None.

References

References

Gustin, M.M., and Ronning, Peter, 2013, Technical Report on the Sun Project, Brooks Range, Alaska, 136 p.: (posted on www.sedar.com, Oct. 3, 2013) http://www.sedar.com/GetFile.do?lang=EN&docClass=24&issuerNo=00019735&fileName=/csfsprod/data147/filings/02118405/00000001/C%3A%5CSEDAR%5CFILINGS%5CAOX%5CAOXSunTechnicalReport.pdf (as of December 4, 2014).
Marrs, C.D., 1978, Geology of the Sun massive sulfide deposit, Ambler district, Alaska [abs.]: Northwest Mining Association, 84th Annual Convention, Spokane, Washington, Nov. 29-Dec. 2, 1978.
Sicherman, H.A., Russell, R.H., and Fikkan, P.R., 1976, The geology and mineralization of the Ambler district, Alaska: Spokane, Wash., Bear Creek Mining Company, 22 p.
Smith, T.E., Profett, J.M., and Heatwole, D.A., 1979, Ambler schist belt of northwest Alaska--Host terrane for volcanogenic base metal massive sulfide deposits of mid-Paleozoic age [abs.]: Geoscience Forum, 7th, Whitehorse, Yukon Territory, December 1979, Abstracts, p. 6.
Smith, T.E., Profett, J.M., Heatwole, D.A., and Seklemian, R.W., 1977, Geologic setting of base metal massive sulfide deposits, Ambler district, northwest Alaska [abs.]: Alaska Geological Society Symposium, 6th, Anchorage, April 1977, Abstracts with Program, p. 41-42.
Zdepski, J.M., 1980, Stratigraphy, mineralogy and zonal relations of the Sun massive-sulfide deposit, Ambler district, northwest Alaska: Fairbanks, University of Alaska, M.Sc. thesis, 93 p.
Reporters A. Angel and V.C. Zinno (Alaska Earth Sciences, Inc.)
Last report date 12/4/2014