|Quadrangle map, 1:250,000-scale||TN|
|Quadrangle map, 1:63,360-scale||A-1|
|Nearby scientific data||Find additional scientific data near this location|
|Location and accuracy||This site represents a bench (terrace) placer mine on Rhode Island Creek just downstream from its junction with Seattle Creek (TN124). The site is in the northeast bank of Rhode Island Creek, on the north side of an unimproved road, in the south half of section 7, T. 4 N., R. 13 W., of the Fairbanks Meridian. The location is accurate within 1,000 feet. The site corresponds to location 39 of Cobb (1972), and roughly to the U.S. Bureau of Land Management site for Rhode Island Creek (MAS number 0020480034), but the MAS site is approximately 1 mile downstream.|
The country rocks in the area of Rhode Island Creek consist of thrust-fault-juxtaposed Cretaceous sandstone, siltstone, and shale, Triassic clastic sedimentary rocks, and Jurassic or Cretaceous quartzite (Chapman and others, 1982; Reifenstuhl and others, 1998). The area also contains small, elongate intrusions of Cretaceous or Tertiary monzodiorite, which have a northeast trend. Rhode Island Creek flows across the strike of the bedrock.
Mining concentrated both on bench deposits and the modern stream channel. The bench deposits on both sides of the creek are 300 feet above the present channel. The easternmost bench deposit is known as Shirley Bar (TN127) (Mertie, 1934). Collier (1903) reported that the local bedrock is schist without quartz veins, but bedrock in the area being hydraulically mined in 1931 consisted of phyllite with quartz stringers (Mertie, 1934). The mined gravels consisted of schist and mafic igneous rocks (Collier, 1903), and the overburden of silt contained mammoth, bison, and other vertebrate remains (Mertie, 1934).
The gold occurs on bedrock and in places has worked into cracks in the bedrock to a depth of several feet (Mertie, 1934). Large amounts of bedrock were often moved in order to recover the gold. The pay streak above the mouth of Gold Run Creek (TN126) was 70 feet wide. Hydraulicking, open cuts, and drift mining were employed, and Rhode Island Creek was economically significant by 1904 (Prindle and Hess, 1905).
Most of the mining took place between 1930 and 1940 (Cobb, 1977). Much of it was done by Archie W. Pringle, who, as of 1951, had been mining there since 1933 (Williams, 1951). His company, Rhode Island Creek Mines, mined the east bench below the mouth of Gold Run Creek (Saunders, 1962). Rhode Island Creek Mines was mining with two bulldozers and a sluice in 1975 (Carnes, 1976). In 1993, Thurman Oil and Mining ran a large placer operation on Rhode Island and Cooney creeks (Bundtzen and others, 1994).Newberry and Clautice (1997) analyzed gold nuggets from Rhode Island Creek by electron microprobe. The gold in the nugget cores is homogeneous with respect to silver content, averaging 20 percent silver. Mercury content in the cores varies from 0.8 to 5 percent, and the fineness of the cores varies from 750 (high Hg) to 840 (low Hg). The rims of most of the gold grains are depleted in mercury, and two of the nuggets also have silver-depleted rims.
|Geologic map unit||(-150.275824938196, 65.1828915034217)|
|Mineral deposit model||Placer Au (Cox and Singer, 1986; model 39a).|
|Mineral deposit model number||39a|
|Age of mineralization||Quaternary.|
|Workings or exploration||Mertie (1934) reported that both surface and underground techniques were employed in mining the bench and creek placer deposits of Rhode Island Creek. These techniques included hydraulicking, open cuts, and drift-mining. Much of this work was done by Archie W. Pringle, who, as of 1951, had been mining there since 1933 (Williams, 1951). His company, Rhode Island Creek Mines, mined the east bench below the mouth of Gold Run (TN126) (Saunders, 1962). Pringle was mining in 1951 on Rhode Island Creek at its confluence with Seattle Creek (TN124) (Williams, 1951). Pringle had been on this creek since 1933 and reportedly had ground available for 5 or 6 more years of mining. Rhode Island Creek Mines was mining with two bulldozers and a sluice in 1975 (Carnes, 1976). In 1993, Thurman Oil and Mining operated a large placer operation on Rhode Island and Cooney creeks (Bundtzen and others, 1994).|
|Indication of production||Yes; small|
|Production notes||No production figures have been published for Rhode Island Creek. However, Cobb (1977) speculated that as much as several tens of thousands of ounces of gold may have been mined from its placers.|
Bundtzen, T.K., Swainbank, R.C., Clough, A.H., Henning, M.W., and Hansen, E.W., 1994, Alaska's mineral industry, 1993: Alaska Division of Geological and Geophysical Surveys Special Report 48, 84 p.
Carnes, D.R., 1976, Active Alaskan placer operations, 1975: U.S. Bureau of Mines Open-File Report 98-76, 90 p., 40 plates, scale 1:250,000.
Chapman, R.M., Yeend, W.E., Brosge, W.P., and Reiser, H.N., 1982, Reconnaissance geologic map of the Tanana quadrangle: U.S. Geological Survey Open-File Report 82-734, 20 p., scale 1:250,000.
Cobb, E.H., 1972, Metallic mineral resources map of the Tanana quadrangle, Alaska: U.S. Geological Survey Miscellaneous Field Studies Map MF-371, 1 sheet, scale 1:250,000.
Cobb, E.H., 1977, Summary of references to mineral occurrences (other than mineral fuels and construction materials) in the Tanana quadrangle, Alaska: U.S. Geological Survey Open-File Report 77-432, 98 p.
Collier, A.J., 1903, The Glenn Creek gold mining district, Alaska: U.S. Geological Survey Bulletin 213, p. 49-56.
Mertie, J.B., Jr., 1934, Mineral deposits of the Rampart and Hot Springs districts, Alaska: U.S. Geological Survey Bulletin 844-D, p. 163-226.
Newberry, R.J. and Clautice, K.H., 1997, Compositions of placer gold in the Rampart-Eureka-Manley-Tofty area, eastern Tanana and western Livengood quadrangles, central Interior Alaska, determined by electron microprobe analysis: Alaska Division of Geological and Geophysical Surveys Public Data File 97-49, 49 p.
Prindle, L.M., and Hess, F.L., 1905, Rampart placer region: U.S. Geological Survey Bulletin 259, p. 104-119.
Reifenstuhl, R.R., Dover, J.H., Newberry, R.J., Clautice, K.H., Pinney, D.S., Liss, S.A., Blodgett, R.B., and Weber, F.R., 1998, Geologic map of the Tanana A-1 and A-2 quadrangles, central Alaska: Alaska Division of Geological & Geophysical Surveys Public Data File 98-37A v. 1.1, 19 p., 1 sheet, scale 1:63,360.
Saunders, R.H., 1963, Mining operations in the Rampart, Manley Hot Springs, and Tolovana Districts: Alaska Territorial Department of Mines Itinerary Report 48-2, 7 p.
|Reporters||G.E. Graham (ADGGS)|
|Last report date||11/15/2000|