Shotgun (Mose)

The Shotgun (Mose) is a gold mine located in Alaska.

About the MRDS Data:

All mine locations were obtained from the USGS Mineral Resources Data System. The locations and other information in this database have not been verified for accuracy. It should be assumed that all mines are on private property.

Mine Info

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Site Name

Primary: Shotgun (Mose)

Commodity

Primary: Gold

Location

State: Alaska
District: Bristol Bay region

Land Status

Not available

Holdings

Not available

Workings

Not available

Ownership

Not available

Production

Not available

Deposit

Record Type: Site
Operation Category: Prospect
Operation Type: Unknown
Years of Production:
Organization:
Significant:

Physiography

Not available

Mineral Deposit Model

Not available

Orebody

Not available

Structure

Not available

Alterations

Alteration Type: L
Alteration Text: Silicification and albite-sericite-quartz +/- carbonate replacement of host intrusive rocks.

Rocks

Not available

Analytical Data

Not available

Materials

Ore: Bismuth
Ore: Chalcocite
Ore: Chalcopyrite
Ore: Copper
Ore: Covellite
Ore: Gold
Ore: Marcasite
Ore: Arsenopyrite
Ore: Tetradymite
Ore: Pyrite
Ore: Pyrrhotite
Ore: Scheelite
Ore: Sphalerite
Ore: Lollingite
Gangue: Albite
Gangue: Quartz
Gangue: Sericite
Gangue: Tourmaline

Comments

Comment (Reserve-Resource): Reserves = Novagold Resources Inc. (2000) has made the following resource estimates: using a cutoff pf 0.018 ounce of Au per ton, the resource is 32,765,000 tons grading 0.033 ounce of Au per ton; using a cutoff of 0.026 ounce of Au per ton, the resource is 16,550,000 tons grading 0.045 ounce of Au per ton; using a cutoff of 0.035 ounce of Au per ton, the resource is 11,650,000 tons grading 0.05 ounce of gold per ton.

Comment (Commodity): Gangue = carbonate

Comment (Geology): Age = Latest Cretaceous. 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that magmatism and mineralization is latest Cretaceous in age, about 68 to 70 Ma (Rombach, 2000; Travis Hudson, unpublished data, 2000).

Comment (Workings): Workings / Exploration = This prospect was discovered in the 1980s as a result of a regional exporation program by Cominco Alaska in joint venture with ENSTAR. They named this prospect Mose and completed surface mapping, sampling, and the drilling of six shallow diamond drill holes. In the 1990s, ENSTAR's interest was sold to NovaGold Resources Inc., the prospect was renamed Shotgun, and a renewed exploration effort took place. This exploration included extensive new diamond drilling in 1998 that included 19 drill holes totaling 10,170 feet. Airborne and ground magnetometer surveys have been used in conjuction with extended mapping and sampling to evaluate the potential for additional deposits in surrounding areas.

Comment (Reference): Primary Reference = Rombach, 2000

Comment (Deposit): Model Name = Gold-bearing quartz-stockwork veining in felsic porphyry

Comment (Geology): Geologic Description = This prospect was discovered in the 1980s as a result of a regional exploration program by Cominco Alaska in a joint venture with ENSTAR. They named this prospect Mose and completed surface mapping, sampling, and the drilling of six shallow diamond drill holes. In the 1990s, ENSTAR's interest was sold to NovaGold Resources Inc., the prospect was renamed Shotgun, and a renewed exploration effort took place. This exploration included extensive diamond drilling in 1998 that included 19 drill holes totaling 10,170 feet (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 intrusive 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 toumaline-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. The vapor-rich inclusions contain, in order of abundance, 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 ppm. Examples of drill hole intercepts include 233 feet grading 0.077 ounce of Au per ton, 399 feet grading 0.050 of ounce Au per ton, and 43 feet grading 0.155 ounce of Au per ton (NovaGold Resources Inc., 2000; all drill hole intercepts are listed online at http://www.nrigold.com/shotgun.htm). Preliminary metallurgical tests indicate that gold recoveries of more than 93 percent can be achieved using conventional cyanidation. A resource estimate, using a 0.018 ounce of Au per ton cutoff, is 32,765,000 tons grading 0.033 ounce of Au per ton. The mineralization is open to the north, west, and at depth. Airborne and ground magnetometer surveys have been used in conjuction with extended mapping and sampling to evaluate the potential for additional mineralization in surrounding areas. 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, down-to-the-south fault. 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).

Comment (Exploration): Status = Active

References

Reference (Deposit): NovaGold Resources Inc., 2000, Shotgun Project: http://www.nrigold.com/shotgun.htp
URL: http://www.nrigold.com/shotgun.htp

Reference (Deposit): Rombach, C.S., 2000, Genesis and mineralization of the Shotgun deposit, southwestern Alaska, in The Tintina gold belt: Concepts, exploration, and discoveries: British Columbia and Yukon Chamber of Mines, Special Volume 2, p. 181-196.

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