Unnamed (near Snipe Bay) (ARDF #PA034) Cu, Ni

Unnamed (near Snipe Bay)

Prospect, Probably inactive

Commodities and mineralogy

Main commodities	Cu; Ni
Ore minerals	chalcopyrite; magnetite; nickeliferous pyrrhotite; pentlandite; pyrite
Gangue minerals	albite; hornblende

Geographic location

Quadrangle map, 1:250,000-scale	PA
Quadrangle map, 1:63,360-scale	B-3
Latitude	56.42213
Longitude	-134.95753
Nearby scientific data	Find additional scientific data near this location
Location and accuracy	This prospect consists of several claims that were staked over a mineralized area about 125 feet by 265 feet that was explored by several pits and drilled. The prospect is near the mouth of Snipe Bay near Snipe Head and about 0.6 mile southwest of the northeast corner of section 9, T. 63 S., R. 67 E. The location is accurate.

Geologic setting

Geologic description The Snipe Bay prospect is associated with a small, poorly exposed elongate body (dike?) of Tertiary gabbro or norite that is largely altered to hornblende, albite, and magnetite (Buddington, 1925; Reed and Gates, 1942). The intrusion is in quartzite and quartz schist in Sitka Graywacke of Cretaceous age (Reed and Gates, 1942; Loney and others, 1975). The mineralization is confined to an area of about 125 by 265 feet. Magnetite, nickeliferous pyrrhotite, chalcopyrite, and pentlandite are disseminated through the altered gabbro or norite and there is one small lens of massive sulfides. The deposit probably is a magmatic segregation deposit (Reed and Gates, 1942; Bittenbender and others, 1999). The deposit was discovered in 1922 (Buddington, 1925; Buddington and Chapin, 1929) and it was prospected intermittently by trenching until 1942 when it was examined by Reed and Gates (1942). The property was acquired by Inspiration Development Company in 1973; they diamond drilled 21 holes and the claims were abandoned in 1979 (Bittenbender and others, 1999). The U.S. Bureau of Mines collected samples for metallurgical testing in 1981 and 1988 (Foley, 1989). Reed and Gates (1942) estimated that the deposit has a conservative minimum resource of 430,000 tons of material with no more than 0.3 percent each of copper and nickel. Foley (1989) estimated a resource of 94,000 tons of material with an average grade of 0.97 percent copper and 0.33 percent nickel.
Geologic map unit	(-134.959310174631, 56.4217506524944)
Mineral deposit model	Cu-Ni magmatic segregation deposit.
Age of mineralization	Probably Tertiary and deposited during the intrusion of a gabbro or norite.
Alteration of deposit	This is a magmatic-segregation deposit in a gabbro or norite that is altered to hornblende, albite, and magnetite.

Production and reserves

Workings or exploration	The deposit was discovered in 1922 (Buddington, 1925; Buddington and Chapin, 1929) and it was prospected intermittently by trenching until 1942 when it was examined by Reed and Gates (1942). The property was acquired by Inspiration Development Company in 1973; they diamond drilled 21 holes and the claims were abandoned in 1979 (Bittenbender and others, 1999). The U.S. Bureau of Mines collected samples for metallurgical testing on 1981 and 1988 (Foley, 1989).
Indication of production	None
Reserve estimates	Reed and Gates (1942) estimated that the deposit has a conservative minimum resource of 430,000 tons of material with no more than 0.3 percent each of copper and nickel. Foley (1989) estimated a resource of 94,000 tons of material with an average grade of 0.97 percent copper and 0.33 percent nickel.
Additional comments The prospect is in the South Baranof Wilderness Area which is closed to mineral exploration and mining. MAS number: 0021160025.

References

MRDS Number	A013373; W000355
References Bittenbender, P., Still, J.C., Maas, K., and McDonald, M., Jr., 1999, Mineral resources of the Chichagof and Baranof Islands area, southeast Alaska: Bureau of Land Management, BLM-Alaska Technical Report 19, 222 p. Brooks, A.H., 1925, Alaska's mineral resources and production, 1923: U.S. Geological Survey Bulletin 773-A, p. 3-52. Buddington, A.F., 1925, Mineral investigations in southeastern Alaska: U.S. Geological Survey Bulletin 773-B, p. 71-139. Buddington, A.F., and Chapin, Theodore, 1929, Geology and mineral deposits of southeastern Alaska: U.S. Geological Survey Bulletin 800, 398 p. Cornwall, H.R., 1968, Nickel deposits of North America: U.S. Geological Survey Bulletin 1223, 62 p. Foley, J.Y., 1989, Snipe Bay copper-nickel-cobalt deposits: Unpublished U.S. Bureau of Mines Field Report, 19 p. (On file at the Juneau Mineral Information Center, U.S. Bureau of Land Management, Juneau, Alaska.) Loney, R.A., Brew, D.A., Muffler, L.J. B., and Pomeroy, J.S., 1975, Reconnaissance geology of Chichagof, Baranof, and Kruzof Islands, southeastern Alaska: U.S. Geological Survey Professional Paper 792, 105 p. Reed, J.C., and Gates, G.O., 1942, Nickel-copper deposits at Snipe Bay, Baranof Island, Alaska: U.S. Geological Survey Bulletin 936-M, p. 321-330. Roberts, W.S., 1983, Minerals Availability System property evaluation file report, Nickel, Snipe Bay, Alaska, Update of property evaluation report by Baggs, D.W.: Unpublished report, U.S. Bureau of Mines, 13 p. (On file at the Juneau Mineral Center, U.S. Bureau of Land Management, Juneau, Alaska.) Smith, P.S., 1938, Mineral industry of Alaska in 1936: U.S. Geological Survey Bulletin 897-A, p. 1-107. Twenhofel, W.S., 1953, Potential Alaskan mineral resources for proposed electrochemical and electrometallurgical industries in the upper Lynn Canal area, Alaska: U.S. Geological Survey Circular 252, 14 p.
Reporters	Donald J. Grybeck (U.S. Geological Survey)
Last report date	2-Jan-05