Hungerford

Prospect, Undetermined

Commodities and mineralogy

Main commodities Ag; Ba; Pb; Zn
Ore minerals barite; galena; sphalerite
Gangue minerals barite; calcite; jasper

Geographic location

Quadrangle map, 1:250,000-scale PA
Quadrangle map, 1:63,360-scale D-1
Latitude 56.88867
Longitude -134.074
Nearby scientific data Find additional scientific data near this location
Location and accuracy The Hungerford prospect is along the shoreline on the north side of the peninsula north of Saginaw Bay. It is about 7.2 miles east-southeast of Cornwallis Point and about 0.5 mile northeast of the center of section 33, T. 57 S., R. 72 E.

Geologic setting

Geologic description

This prospect is one of a group of similar deposits (PA021 to PA031) that are scattered along the south shore of Saginaw Bay, on the peninsula north of Saginaw Bay, and on the Keku Islands. They occur in a heterogeneous section of unmetamorphosed volcanic, carbonate, and clastic rocks that vary in age from Silurian to Triassic (Muffler, 1967). The mineralization generally consists of veins, veinlets, and irregular pods that contain base metals and barite (Still and others, 2002). There are no plutonic rocks in the immediate vicinity; however, the sedimentary rocks are cut by scattered gabbro dikes. The origin of the deposits is uncertain although most appear to be epigenetic. Various origins have been proposed including that they are remobilized massive-sulfide deposits, that they are related to a buried intrusive, or that they are Mississippi-Valley-type deposits.
The Hungerford prospect was discovered in 1937; it was restaked in 1948 and by 1950, the prospect consisted of a small cabin and several open cuts (Roehm, 1938 [PE 116-1]; Thorne, 1950 [Hungerford]; Thorne, 1950 [Hungerford, Supplementary]). The U.S. Bureau of Mines drilled 5 holes totaling 982 feet in 1949.
The Hungerford prospect is in Keku Volcanics of Triassic age; at this site, the unit consists of a heterogeneous assemblage of conglomerate, basalt, shale, and dolomitic limestone (Muffler, 1967). Detailed mapped by the U.S. Bureau of Mines in 1949 (Thorne, 1950 [Hungerford]; Thorne, 1950 [Hungerford, Supplementary]; Still and others, 2002) defined three types of mineralization: 1) disseminated galena and sphalerite in amygdaloidal basalt; 2) a stockworks of galena-sphalerite veins in fractured green basalt, and 3) galena and sphalerite replacing dolomite.
The main deposit at the Hungerford prospect consists of fine-grained sphalerite and galena in amygdaloidal basalt. A sample contained 84.7 parts per million (ppm) silver, 2.23 percent lead and 7,028 ppm zinc (Still and others, 2002). The Bureau of Mines drilling in 1949 resulted in the definition of an 'ore body' that has an estimated resource of 63,000 tons of 'submarginal ore' with an average grade of 2.4 ounces of silver per ton, 1.35 percent lead, and 0.45 percent zinc (Thorne, 1950 [Hungerford]; Thorne, 1950 [Hungerford, Supplementary]. The ore body is 78 to 93 feet thick and extends for 280 feet along strike. The drilling suggests that the grade decreases with depth.
Galena and sphalerite in barite-jasper gangue occurs in a stockwork of veins in the bed of Hungerford Creek (Still and others, 2002). A sample contained 16.4 ppm silver, 5,625 ppm lead, 6,019 ppm zinc, and 14.6 percent barite. A similar deposit marked by brecciation and open-space filling occurs along the beach nearby. A sample contained 5.82 ounces of silver per ton, 2.84 percent lead, 2,228 ppm zinc, and 70 ppm barium. Thorne (1948) also reported that sphalerite and galena replace dolomite in bluffs along the beach.
Geologic map unit (-134.075721625388, 56.8883346427515)
Mineral deposit model Disseminated, vein, and replacement sphalerite and galena in basalt and carbonate rocks.
Age of mineralization Younger than the Triassic host rocks.

Production and reserves

Workings or exploration The Hungerford prospect was discovered in 1937; it was restaked in 1948 and by 1950, the prospect consisted of a small cabin and several open cuts (Roehm, 1938 [PE 116-1]; Thorne, 1950 [Hungerford]; Thorne, 1950 [Hungerford, Supplementary]). The U.S. Bureau of Mines drilled 5 holes totaling 982 feet in 1949.
Indication of production None
Reserve estimates Bureau of Mines drilling in 1949 resulted in a the definition of an 'ore body' that has an estimated resource of 63,000 tons of 'submarginal ore' with an average grade of 2.4 ounces of silver per ton, 1.35 percent lead, and 0.45 percent zinc (Thorne, 1950 [Hungerford]; Thorne, 1950 [Hungerford, Supplementary]. The ore body is 78 to 93 feet thick and extends for 280 feet along strike. The drilling suggests that the grade decreases as depth.

Additional comments

The prospect is on land that has been selected for patent by the Sealaska Native Corporation and the Kake Tribal Corporation.
MAS number: 0021160004.

References

References

Still, J.C., Bittenbender, P.E., Bean, K.W., and Gensler, E.G., 2002 Mineral assessment of the Stikine area, central Southeast Alaska: U.S. Bureau of Land Management Technical Report 51, 560 p.
Thorne, R.L., 1948, Hungerford prospect, Kuiu Island: Unpublished U.S. Bureau of Mines Memorandum, 2 p. (On file at the Juneau Mineral Center, U.S. Bureau of Land Management, Juneau, Alaska.)
Thorne, R.L., 1950, Investigation of the Hungerford property, Kuiu Island lead-zinc, southeastern Alaska: Unpublished U.S. Bureau of Mines Report of Investigations, 10 p. (On file at the Juneau Mineral Center, U.S. Bureau of Land Management, Juneau, Alaska.)
Thorne, R.L., 1950, The Hungerford property, Kuiu lead-zinc, southeastern Alaska: U.S. Bureau of Mines Supplementary Report, 5 p. (On file at the Juneau Mineral Center, U.S. Bureau of Land Management, Juneau, Alaska.)
Reporters Donald J. Grybeck (U.S. Geological Survey)
Last report date 2-Jan-05