|Quadrangle map, 1:250,000-scale||CY|
|Quadrangle map, 1:63,360-scale||A-3|
|Nearby scientific data||Find additional scientific data near this location|
|Location and accuracy||Ruby Creek is a northeast-flowing tributary of Fourth of July Creek (CY015). It is location 7 of Cobb (1972 [MF-390]). The deposit is located midway up Ruby Creek, about a mile from its head. The placer mining occurs just upstream of the confluence with an unnamed creek entering from the southeast, in section 4, T. 3 N., R. 28 E., of the Fairbanks Meridian. The location is accurate to within one mile.|
The bedrock of Ruby Creek is composed of Cretaceous to Tertiary conglomerate and other sedimentary rocks (Dover and Miyaoka, 1988). The placer gold is found in the 20 inches of gravel above bedrock; bedrock was 12 to 15 feet from the surface in 1912 (Prindle and Mertie, 1912).The creek was first mined in the early 1900s. Mining was by open-cut methods because the bedrock was less than 15 feet below the surface. Values of $50 to $75 per 12-foot by 12-foot sluice box were reported in the early 1900s (1901-1910 dollars). Mining operations were frequently constrained by a lack of water. In 1926, production was 5 ounces of gold and one ounce of silver (National Park Service, 1990).
|Geologic map unit||(-143.162393186901, 65.2896676708208)|
|Mineral deposit model||Placer Au (Cox and Singer, 1986; model 39a).|
|Mineral deposit model number||39a|
|Age of mineralization||Quaternary.|
|Workings or exploration||The creek was first mined in the early 1900s, but more mining activity occurred in 1911. Mining was by open-cut methods because the bedrock was less than 15 feet below the surface. Mining operations were frequently constrained by a lack of water (National Park Service, 1990).|
|Indication of production||Yes; small|
|Production notes||In 1926, production was 5 ounces of gold and one ounce of silver (National Park Service, 1990). Values of $50 to $75 per 12-foot by 12-foot sluice box were reported in the early 1900s.|
Additional commentsSee also Fourth of July Creek (CY015). This site is within the Yukon-Charley Rivers National Preserve.
Chapin, Theodore, 1914, Placer mining in the Yukon-Tanana region: U.S. Geological Survey Bulletin 592-J, p. 357-362.
Cobb, E.H., 1972, Metallic mineral resources map of the Charley River quadrangle, Alaska: U.S. Geological Survey Miscellaneous Field Studies Map MF-390, 1 sheet, scale 1:250,000.
Cobb, E.H., 1976, Summary of references to mineral occurrences (other than mineral fuels and construction materials) in the Charley River and Coleen quadrangles, Alaska: U.S. Geological Survey Open-File Report 76-632, 45 p.
Dover, J.A., and Miyaoka, R.T., 1988, Reinterpreted geologic map and fossil data, Charley River quadrangle, east-central Alaska: U.S. Geological Survey Miscellaneous Field Studies Map MF-2004, 2 sheets, scale 1:250,000.
National Park Service, 1990, Final environmental impact statement, volume 1, Mining in Yukon-Charley Rivers National Preserve, Alaska: National Park Service, Anchorage, Alaska, p. 36-44.
Prindle, L.M., 1913, A geologic reconnaissance of the Circle quadrangle, Alaska: U.S. Geological Survey Bulletin 538, 82 p.
|Reporters||C.E. Cameron (ADGGS)|
|Last report date||4/7/2000|