Shotgun

Prospect, Active

Alternative names

Mose

Commodities and mineralogy

Geographic location

Quadrangle map, 1:250,000-scale TA
Quadrangle map, 1:63,360-scale B-6
Latitude 60.386
Longitude -158.0687
Nearby scientific data Find additional scientific data near this location
Location and accuracy The Shotgun prospect is in the southern part of the Shotgun Hills, a rugged, glaciated upland at the head of the King Salmon River. The prospect is near the center of the NW1/4 section 27, T. 4 N., R. 51 W., of the Seward Meridian. It is on the crest and eastern slope of a northwest-trending ridge at an elevation of about 2,500 feet. The location is accurate to within 500 feet.

Geologic setting

Geologic description

This prospect was discovered in the 1980s in a regional exploration program by Cominco Alaska in joint venture with ENSTAR. They named this prospect Mose and completed surface mapping, sampling, and drilled six shallow diamond drill holes. In the 1990s, ENSTAR's interest was sold to NovaGold Resources Inc., the prospect was renamed Shotgun, and renewed exploration took place (NovaGold Resources Inc., 2000).
The Shotgun prospect is an intensely quartz-veined, felsic porphyry stock that sharply crosscuts biotite hornfels developed in mid-Cretaceous clastic sedimentary rocks of the Kuskokwim Group (Rombach, 2000). As exposed along the ridge crest and downslope to the east, the stock is an irregularly shaped composite intrusion that is about 1,000 feet long in a northwest direction and over 500 feet long in a northeast direction. The hornfels near the stock and across the ridge crest to the southwest commonly is breccia healed by a tourmaline-rich matrix and locally cut by veinlets that contain arsenopyrite, pyrite, and some chalcopyrite. In the stock, some zones near the contact are extensively silicified; quartz replacement is massive and complete in these zones. Elsewhere, the stock is cut by quartz veins that in places form an intense, anastomosing stockwork. Albite-sericite-quartz +/- carbonate replacement of host intrusive rocks accompanies the quartz veining. The deposit is deeply oxidized and iron-staining is widespread. Ore minerals identified at Shotgun include arsenopyrite, primary native gold and bismuth, Bi-Te sulfides, chalcopyrite, lollingite, pyrrhotite, pyrite, scheelite, sphalerite, and supergene covellite, chalcocite, native copper, and marcasite (Rombach, 2000).
Vapor-rich and saline-rich fluid inclusions coexist in the quartz veins. In order of abundance, the vapor-rich inclusions contain water, carbon dioxide, and methane; these inclusions homogenize to vapor at about 360 degrees C. The saline-rich inclusions have salinities of 40 to greater than 60 weight percent NaCl equivalent and homogenize to liquid at 280 to more than 600 degrees C (Rombach, 2000).
Surface rock samples define a large geochemical anomaly with several areas where gold values exceed 1 part per million. Examples of drill hole intercepts include 233 feet grading 0.077 ounce of gold per ton, 399 feet grading 0.050 ounce of gold per ton, and 43 feet grading 0.155 ounce of gold per ton (NovaGold Resources Inc., 2000; all drill hole intercepts are listed online at http://www.nrigold.com/shotgun.htm; Dec 2000). Preliminary metallurgical tests indicate that gold recoveries of more than 93 percent can be achieved using conventional cyanidation. Airborne and ground magnetometer surveys have been used in conjunction with extended mapping and sampling to evaluate the potential for additional mineralization in surrounding areas. As of March 28, 2007, NovaGold Resources, Inc. (2007) reports that the Shotgun prospect has 32.8 million tonnes of resources with a grade of 0.93 gram of gold per ton.
A large granitic pluton makes up the core of the Shotgun Hills. The contact between this pluton and the hornfels that surrounds the Shotgun prospect coincides with a northwest-trending linear swale and drainage less than 0.5 mile north of the prospect. The shallow-seated intrusive environment south of this contact (extensive hornfels locally cut by fine-grained porphyry) compared to that to the north, suggests that this contact is a large fault, dropped down to the south. K/Ar and Ar/Ar dating of intrusive rocks and mineralization in the Shotgun prospect area indicate that magmatism and mineralization is latest Cretaceous in age, about 68 to 70 Ma (Rombach, 2000; Travis Hudson, unpublished data, 2000).
TNR Gold Corporation optioned Shotgun (Mose) from NovaGold Resources, Inc. in 2003. A running history of TNR Gold's work to April 2007 can be seen in several news releases and project information at their web site (TNR Gold Corp., 2007). In 2011 and 2012, TNR collected 3D IP resistivity and chargeability geophysical surveys at Shotgun. In 2012, three drill holes totaling 814 meters were completed (Van Wyck and Armitage, 2013).
TNR Gold Corp. commissioned GeoVector Management Inc. ('GeoVetor') to produce a resource estimate on the Property in 2013. Geovector reported an Inferred Resource of 20,734,313 tonnes at 1.06 grams of gold per tonne for a total of 705,960 ounces gold using a 0.5 gram of gold per tonne cut-off grade (TNR Gold Corp., 2013; Athey and Werdon, 2017).
Geologic map unit (-158.127455854894, 60.4087862027392)
Mineral deposit model Gold-bearing quartz-stockwork veining in felsic porphyry.
Age of mineralization Latest Cretaceous, 68 to 70 Ma, based on K/Ar and Ar/Ar dating of intrusive rocks and mineralization (Rombach, 2000).
Alteration of deposit Silicification and albite-sericite-quartz +/- carbonate replacement of host intrusive rocks (Rombach, 2000).

Production and reserves

Workings or exploration
This prospect was discovered in the 1980s in a regional exploration program by Cominco Alaska in joint venture with ENSTAR. They named this prospect Mose and completed surface mapping, sampling, and drilled six shallow diamond drill holes. In the 1990s, ENSTAR's interest was sold to NovaGold Resources Inc., the prospect was renamed Shotgun, and renewed exploration took place. This exploration included extensive new diamond drilling in 1998 that included 20 drill holes totaling 10,192 feet. Airborne and ground magnetometer surveys have been used in conjunction with extended mapping and sampling to evaluate the potential for additional deposits in surrounding areas. Drilling results from this year included 14 drill holes intersecting over 20 meters that averaged over 1 gram of gold per tonne with the largest intercept at 121.5 meters at 1.41 grams of gold per tonne in drill hole 98-09 (Rombach, 2000).
TNR Gold Corporation optioned Shotgun (Mose) from NovaGold Resources, Inc. in 2003. A running history of TNR Gold's work to April 2007 can be seen in several news releases and project information at their web site (TNR Gold Corp., 2007). Initial exploration under this agreement was in September 2003 and included surface geologic mapping and an airborne magnetic survey. TNR Gold Corporation's exploration work during the summer of 2004 included surface geologic mapping and sampling at Shotgun (Mose) and other prospects including Shot (TA031), King (TA030), and Beats Me (TA029). In the summer of 2005, the TNR Gold Corporation exploration program included drilling 6 holes to further refine and expand the resource at Shotgun (Mose) and evaluate other prospects in the area. In 2006, drilling from one drill hole (06-43) intersected 210.5 meters of 1.28 grams of gold per tonne (Harrop, 2008).
In 2011 and 2012, TNR collected 3D IP resistivity and chargeability geophysical surveys at Shotgun. In 2012, three drill holes totaling 814 meters were completed. A resource estimate and technical report followed in 2013. An Inferred Resource of 20,734,313 tonnes at 1.06 grams per tonne for a total of 705,960 ounces gold using a 0.5 gram of gold per tonne cut-off grade was estimated. Mineralization, as defined by a 3D computer model, is approximately 360 meters long trending at 55 degrees, and extends from the ground surface to a depth of up to 240 meters. Mineralization remains open at depth (Van Wyck and Armitage, 2013).
TNR Gold Corp. commissioned GeoVector Management Inc. ('GeoVetor') to produce a resource estimate on the Property in 2013. Geovector reported an Inferred Resource of 20,734,313 tonnes at 1.06 grams of gold per tonne for a total of 705,960 ounces gold using a 0.5 gram of gold per tonne cut-off grade (TNR Gold Corp., 2013; Athey and Werdon, 2017).
Indication of production None
Reserve estimates
In 2012, three drill holes totaling 814 meters were completed. A resource estimate and technical report followed in 2013. An Inferred Resource of 20,734,313 tonnes at 1.06 grams per tonne for a total of 705,960 ounces gold using a 0.5 gram of gold per tonne cut-off grade was estimated. Mineralization, as defined by a 3D computer model, is approximately 360 meters long trending at 55 degrees, and extends from the ground surface to a depth of up to 240 meters. Mineralization remains open at depth (Van Wyck and Armitage, 2013).
TNR Gold Corp. commissioned GeoVector Management Inc. ('GeoVetor') to produce a resource estimate on the Property in 2013. Geovector reported an Inferred Resource of 20,734,313 tonnes at 1.06 grams of gold per tonne for a total of 705,960 ounces gold using a 0.5 gram of gold per tonne cut-off grade (TNR Gold Corp., 2013; Athey and Werdon, 2017).
Production notes None.

Additional comments

In 2010, TNR Gold Corp. announced an increase to 100 percent undivided ownership interest in the Shotgun project through the acquisition of NovaGold Resources outstanding 50 percent (TNR Gold Corp., 2010).

References

References

Harrop, J., 2008, Technical Report on the Shotgun - Winchester Project, SW Alaska: http://sedar.com/GetFile.do?lang=EN&docClass=24&issuerNo=00004948&fileName=/csfsprod/data87/filings/01228299/00000001/p%3A%5Cdwnlds%5CTNRGoldTechRepMar11.pdf (posted on www.sedar.com, March 11, 2008, as of December 3, 2014).
NovaGold Resources Inc., 2000, Shotgun Project: http://www.nrigold.com/shotgun.htp.
NovaGold Resources Inc., 2007 (Reserve): (http://www.novagold.net/i/pdf/NGReserve_ResourceTable.pdf (March, 2007).
Rombach, C.S., 2000, Genesis and mineralization of the Shotgun deposit, southwestern Alaska, in Tintina gold belt; Concepts, exploration, and discoveries: British Columbia and Yukon Chamber of Mines, Cordilleran Roundup, Special Volume 2, p. 181-196.
TNR Gold Corp, 2010, 100% Interest Negotiated on Shotgun Gold Project, Alaska: http://www.tnrgoldcorp.com/index.php/news/2010-news/137-100-interest-negotiated-on-shotgun-gold-project-alaska, News Release dated September 20, 2010 (as of July 21, 2014).
TNR Gold Corporation, 2007: http://www.tnrgoldcorp.com (as of April 2007).
Van Wyck, N., and Armitage, A., 2013, Technical Report on the Shotgun Gold Project, Southwest Alaska, prepared for TNR Gold Corp. (www.sedar.com, published May 27, 2013): http://sedar.com/GetFile.do?lang=EN&docClass=24&issuerNo=00004948&fileName=/csfsprod/data143/filings/02069651/00000001/l%3A%5CSEDAR%5CTNRGoldCorp%5CTechnicalReportandConsents%5CTechnicalReport.pdf (as of December 12, 2014).
Reporters Travis L. Hudson (Applied Geology, Inc.); V.C. Zinno (Alaska Earth Sciences, Inc.); M.B. Werdon (DGGS)
Last report date 8/26/2017