|Quadrangle map, 1:250,000-scale||PE|
|Quadrangle map, 1:63,360-scale||D-3|
|Nearby scientific data||Find additional scientific data near this location|
|Location and accuracy||This small mine can be been in outcrop just above the high-tide level on the eastern shoreline of Thomas Bay. It is near an unnamed point about 0.6 mile south of Spray Island in the NW1/4, section 25, T. 56 S., R. 79 E. The location is accurate.|
Buddington (1923) described this deposit as a quartz vein that can be traced for about 250 feet. It consists of a sheeted zone at least 12 feet thick; about half of the sheeted zone is milky-white quartz and half schist. The property was active intermittently until at least into the 1940s. In 1949, 6 tons of ore was mined that produced 6 ounces of gold and 1 ounce of silver. The quartz veins contain sparse, disseminated pyrite, arsenopyrite, chalcopyrite, pyrrhotite, and galena; specimens of arsenopyrite several inches across are common on the dump. The workings are less than 200 feet from the shore line and include two short adits, one 21 feet long and the other 71 feet long, and a trench. The rocks in the area consist of biotite schist and gneiss, gneissic granodiorite, and quartz monzodiorite (Brew and others, 1984).Maas and Redman (1989) mapped and sampled the workings. One of their samples of a 4-inch-wide quartz vein contained 6,975 parts per billion (ppb) gold; their other 7 samples averaged 371 ppb gold. Still and others (2002) examined the property in 1998. They sampled the mineralized zones which are 3.5 to 6 feet thick. Their highest grade sample across 3.5 feet of vein contained 589 ppb gold but the average of their 8 samples was 137 ppb gold.
|Geologic map unit||(-132.795516420987, 56.9893620929504)|
|Mineral deposit model||Low-sulfide gold-quartz vein (Cox and Singer, 1986; model 36a)|
|Mineral deposit model number||36a|
|Age of mineralization||Cretaceous or younger based on the age of the metamorphic host rock.|
|Alteration of deposit||Unknown or minor.|
|Workings or exploration||There was some minor development on the prospect prior to 1921. The property was active intermittently until at least into the 1940s. A claim was active as recently as 1979.|
|Indication of production||None|
|Production notes||In 1949, 6 tons of ore was mined that produced 6 ounces of gold and 1 ounce of silver.|
Brew, D.A., Ovenshine, A.T., Karl, S.M., and Hunt, S.J., 1984, Preliminary reconnaissance geologic map of the Petersburg and parts of the Port Alexander and Sumdum 1:250,000 quadrangles, southeastern Alaska: U.S. Geological Survey Open-File Report 84-405, 43 p., 2 sheets, scale 1:250,000.
Buddington, A.F., 1923, Mineral deposits of the Wrangell district: U.S. Geological Survey Bulletin 739-B, p. 51-75.
Cobb, E.H., 1972, Metallic mineral resources map of the Petersburg quadrangle, Alaska: U.S. Geological Survey Miscellaneous Field Studies Map MF-415, 1 sheet, scale 1:250,000.
Cobb, E. H., 1972, Summary of references to mineral occurrences (other than mineral fuels and construction materials) in the Petersburg Quadrangle, Alaska: U.S. Geological Survey Open-File Report 78-870, 53 p.
Grybeck, D.J., Berg, H.C., and Karl, S.M., 1984, Map and description of the mineral deposits in the Petersburg and eastern Port Alexander quadrangles: U.S. Geological Survey Open-File Report 84-837, 86 p., 1 sheet, scale 1:250,000.
Maas, K.M., and Redman, E.C., 1989, Notes and sketch map of Cascade Mine: Unpublished report by the U.S. Bureau of Mines, 1 sheet, 3 p. (On file at the Bureau of Land Management, Minerals Information Center, Juneau, Alaska.)
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.
U.S. Bureau of Mines, 1980, Claim map, Petersburg quadrangle, Alaska: U.S. Bureau of Mines Map 117, 1 sheet, scale 1:250,000.
|Reporters||D.J. Grybeck (Port Ludlow, WA)|
|Last report date||4/8/2007|