|Quadrangle map, 1:250,000-scale||SK|
|Quadrangle map, 1:63,360-scale||B-4|
|Nearby scientific data||Find additional scientific data near this location|
|Location and accuracy||The location of this mine is somewhat arbitrary as gold placer mining occurred at various localities along Nugget Creek. It is plotted approximately 1/2 mile up Nugget Creek from its junction with the Tsirku River. It is in the SE1/4, section 5, T. 30 S., R. 55 E. of the Copper River Meridian. It is shown as location 30 by Cobb (1972 [MF 424]) and sample location 180 by Still and others (1984).|
Some gold was mined on Nugget Creek beginning in 1899 and there has been sporadic mining since. Production has probably been small (Hoekzema and others, 1986). Wright (1904 [B 225 and B 236]) describes the deposit as primarily creek-bed gravels and low side-bench gravels. Deposits in the creek occur as rich pockets in potholes. The low- bench deposits are usually very narrow and from the bottom upward, typically consist of a 2-foot layer of glacial mud, a foot or more of cemented slate wash, a 10-foot bed of pay dirt, and a few feet of colluvium. Many large blocks of diorite occur in the pay gravels and substantially add to the cost of mining. However, Hoekzema and others (1986) also cite the presence of abandoned channels at higher elevations on the east side of the creek and an alluvial fan at the mouth of the creek. They report that alluvium in the lower canyon is 12 to 20 feet deep and that gold is found on or near bedrock,; little gold is found in the overlying gravels. The best value obtained by the U.S. Bureau of Mines contained 0.0138 ounces of gold per cubic yard in a sample collected from an abandoned channel adjacent to the Tsirku River. Gravel resources in the existing stream channel are small but have been shown to contain coarse gold by recent suction dredge operations. The average stream gradient is over 900 feet per mile.The Nugget Creek placer mineralization lies within a northwest-trending zone of quartz-sulfide veining in sediments and slates in the Skagway B-4 quadrangle described by Wright (1904 [B 225 and B 236], Eakin (1918 and 1919), and MacKevett and others (1974) and considered to be the source of placer gold in this area.
|Geologic map unit||(-136.181869143887, 59.289648908562)|
|Mineral deposit model||Alluvial fan and paleo-channel placer deposits (Cox and Singer, 1986; model 39a).|
|Mineral deposit model number||39a|
|Age of mineralization||Quaternary placer.|
|Workings or exploration||Placer gold was discovered in 1899 but there was no development until 1902 (Wright, 1904 [B 236]). Sporadic mining occurred in 1902 to 1913, 1929, and since 1980 (Hoekzema and others, 1986). Remains of a small hydraulic plant exist on east side of creek 1.5 miles above junction with Tsirku River. A flume was used to divert the creek between 1902 and 1909 for hydraulic methods (Hoekzema and others, 1986). Gravels in the lower section of the Nugget Creek canyon were tested with suction dredges between 1980 and 1985 with encouraging results. The alluvial fan at the mouth of Nugget Creek was patented in 1934 (Hoekzema and others, 1986).|
|Indication of production||Yes; small|
|Reserve estimates||A significant but untested, identified resource exists in the alluvial fan at the mouth of the creek which coalesces with the fan at the mouth of Cottonwood Creek to the west. Abandoned channels that may host placer gold have been identified in the fan between Cottonwood and Nugget Creeks (Hoekzema and others, 1986).|
|Production notes||Approximately 350 ounces of gold was produced by small hydraulic operations between 1902 and 1909 (Eakin, 1919).|
Berg, H.C., 1984, Regional geologic summary, metallogenesis, and mineral resources of southeastern Alaska: U.S. Geological Survey Open-file Report 84-572, 298 p., 1 plate, scale 1:600,000.
Cobb, E.H., 1972, Metallic mineral resources map of the Skagway quadrangle, Alaska: U.S. Geological Survey Miscellaneous Field Studies Map MF-424, 1 sheet, scale 1:250,000.
Cobb, E.H., 1978, Summary of references to mineral occurrences (other than mineral fuels and construction materials) in the Mt. Fairweather and Skagway quadrangles, Alaska: U.S. Geological Survey Open-File Report 78-316, 123 p.
Eakin, H.M., 1918, Gold placer mining in the Porcupine district: U.S. Geological Survey Bulletin 662-B, p. 93-100.
Eakin, H.M., 1919, The Porcupine gold placer district, Alaska: U.S. Geological Survey Bulletin 699, 29 p.
Hoekzema, R.B., Fechner, S.A., and Bundtzen, T.K., 1986, Distribution, analysis, and recovery of placer gold from the Porcupine mining area, southeast Alaska: U.S. Bureau of Mines Open-File Report 89-86, 49 p., 4 sheets.
Redman, E.C., Gilbert, W.G., Jones, B.K., Rosenkrans, D.S., and Hickok, B.D., 1985, Preliminary bedrock-geologic map of the Skagway B-4 quadrangle: Alaska Division of Geological and Geophysical Surveys Report of Investigations 85-6, 1 sheet, scale 1:40,000.
Still, J.C., 1991, Section A: Haines - Klukwan - Porcupine subarea, in U.S. Bureau of Mines, Mineral investigations in the Juneau Mining District, Alaska, 1984-1988: Volume 2 - Detailed mine, prospect, and mineral occurrence descriptions: U.S. Bureau of Mines Special Publication VOL. 2A, 214 p., 9 sheets.
Still, J.C., Hoekzema, R.B., Bundtzen, T.K., Gilbert, W.G., Wier, K.R., Burns, L.E., and Fechner, S.A., 1991, Economic geology of Haines-Klukwan-Porcupine area, southeastern Alaska: Alaska Division of Geological and Geophysical Surveys Report of Investigations 91-4, 156 p., 5 sheets, scale 1:63,360.
Still, J.C., Weir, K.R., Gilbert, W.G., and Redman, Earl, 1984, Stream sediment, float, and bedrock sampling in the Porcupine mining area, southeast Alaska: U.S. Bureau of Mines Open-File Report 173-84, 6 p., 1 sheet, scale 1:250,000.
Wright, C.W., 1904, The Porcupine placer district, Alaska: U.S. Geological Survey Bulletin 236, 35 p.
|Reporters||T.C. Crafford (T. Crafford & Associates, Anchorage)|
|Last report date||2/4/2001|