Nim

Prospect, Active

Commodities and mineralogy

Main commodities Ag; Au; Cu; Mo
Other commodities Pb; Zn
Ore minerals arsenopyrite; bornite; chalcocite; chalcopyrite; galena; molybdenite; pyrite; sphalerite
Gangue minerals quartz

Geographic location

Quadrangle map, 1:250,000-scale HE
Quadrangle map, 1:63,360-scale B-5
Latitude 63.28
Longitude -149.43
Nearby scientific data Find additional scientific data near this location
Location and accuracy The Nim claim block at its acme, comprised 168 claims. The block was approximately rectangular, with the long axis oriented NE - SW. The center of the prospect area is at the intersection of secs. 10, 11, 14, and 15, T. 19 S., R. 10 W., of the Fairbanks Meridian. The location is accurate to within 0.5 mile.

Geologic setting

Geologic description

The country rocks in the area of the Him prospect include Upper Triassic to Upper Jurassic crystal tuff, argillite, chert, graywacke, and limestone, which are intruded successively by hypabyssal garnetiferous diorite porphyry, and by monzonite porphyry and quartz porphyry. The intrusive rocks are correlated with similar Upper Cretaceous plutons at the Golden Zone mine (HE043) (Swainbank and others, 1977). The deposits consists chiefly of pluton-hosted, porphyry-type disseminations of arsenopyrite, bornite, chalcocite, chalcopyrite, and molybdenite in a 4,000- by 4,000-foot area. Selected bedrock samples assay as high as 5% copper, 360 ppm molybdenite, 2 ppm gold and 9 ounces of silver per ton.
In addition to the porphyry-type deposit. mapping and geophysical methods indicate 5 breccia-pipe anomalies similar to those at the Golden Zone mine (Bundtzen and others, 1984). The Nim deposit has a slightly different geochemical signature from the Golden Zone mine (Nim is higher in molybdenum-copper, lower in gold), but its hybrid breccia-porphyry mineralization, small alteration haloes, and complex mineralogy are essentially the same as at the Golden Zone mine.
Geologic map unit (-149.432287362507, 63.2795303731212)
Mineral deposit model Polymetallic vein, Au-Ag breccia pipe, or Cu-Au porphyry (Cox and Singer, 1986; models 22c, 20c)
Mineral deposit model number 22c, 20c
Age of mineralization The similarity of the Nim deposit to the Upper Cretaceous (70-65 Ma) Golden Zone mine (HE043) suggests that they are probably the same age.
Alteration of deposit Alteration consists of widespread propylitic alteration and silicification. Local zones of potassic alteration marked by secondary biotite reported.

Production and reserves

Workings or exploration
Exploration in the late 1970s consisted of at least 18 shallow RC drill holes into the Snoopy and Nim areas. IP and magnetic surveys have also been conducted on the property (Bundtzen, 1983).
Selected bedrock samples assay as high as 5% copper, 360 ppm molybdenite, 2 ppm gold and 9 ounces of silver per ton.
Indication of production None

References

MRDS Number A011325

References

Salisbury and Dietz, Inc., 1984, 1983 mineral resource studies--Kantishna Hills and Dunkle Mine areas, Denali National Park and Preserve, Alaska: U.S. Bureau of Mines, Contract No. S0134031, 1,080 p.
Reporters N. Van Wyck (Stevens Exploration Management Corporation)
Last report date 4/7/2000