|Quadrangle map, 1:250,000-scale||RB|
|Quadrangle map, 1:63,360-scale||C-5|
|Nearby scientific data||Find additional scientific data near this location|
|Location and accuracy||Big Creek is a curved stream with west-flowing headwaters that turn northward toward the Yukon River and curve southeast toward the flats of the Nowitna River before curling to flow northwest into the Yukon River. The Big Creek placer area, location 4 of Cobb (1972 [MF405]), stretches almost a mile on the headwaters of the creek, two miles northwest of Boston Dome and 5 air-miles south of the Yukon River. The coordinates above mark the center of the mined area, in section 33, T. 9 S., R. 17 E. of the Kateel River meridian. The location is accurate within 1/4 mile. Big Creek is located within Doyon, Ltd.'s Ruby Village Block.|
Geologic descriptionThe bedrock underlying Big Creek consists of slate and granite, both cut by veins of quartz and tourmaline (Eberlein and others, 1977). Big Creek was prospected in 1910; miners sank 15 holes 15 to 60 feet down until they hit slaty bedrock (Maddren, 1910). A 1 to 7-foot-thick gravel layer on the bedrock was found to be auriferous (Maddren, 1910). Pyrite occurs in gravel and attached to large fragments of bedrock. Cassiterite is also abundant in the placer gravels. The pay streak is about 30 feet wide and 1 to 15 feet thick and may extend as much as 5,000 feet downstream from the mouth of Cox Pup (Chapman and others, 1963). In the upper valley, about 0.04 pound cassiterite and 0.0052 ounce of gold per cubic foot can be panned from dumps of prospect holes (Chapman and others, 1963). Sporadic mining took place along the creek between 1907 and the 1940s. Big Creek was also prospected during more recent years by several larger companies (Pete Haggland, oral communication, 2000).
|Geologic map unit||(-155.464663337352, 64.6619677171011)|
|Mineral deposit model||Placer Au (Cox and Singer, 1986; model 39a).|
|Mineral deposit model number||39a|
|Age of mineralization||Quaternary|
|Workings or exploration||Around 1910, miners sank 15 holes 15 to 60 feet down to slaty bedrock (Maddren, 1910). Most of the ground is not frozen and is difficult to work by drift mining. Sporadic mining took place along the creek between 1907 and the 1940s (Chapman and others, 1963). Big Creek was also prospected during more recent years by several larger companies (Pete Haggland, oral communication, 2000).|
|Indication of production||Yes; small|
Additional commentsSee also Cox Pup (RB011).
Chapman, R.M., Coats, R.R., and Payne, T.G., 1963, Placer tin deposits in central Alaska: U.S. Geological Survey Open-File Report 239, 53 p.
Cobb, E.H., 1972, Metallic mineral resources map of the Ruby quadrangle, Alaska: U.S. Geological Survey Miscellaneous Field Studies Map MF-405, 1 sheet, scale 1:250,000.
Cobb, E.H., and Chapman, R.M., 1981, Mineral occurrences (other than mineral fuels and construction materials) in the Kantishna River and Ruby quadrangles, Alaska: U.S. Geological Survey Open-File Report 81-170, 94 p.
Eberlein, G.D., Chapman, R.M., Foster, H.L., and Gassaway, J.S., 1977, Map and table describing known metalliferous and selected nonmetalliferous mineral deposits in central Alaska: U.S. Geological Survey Open-File Report 77-168-D, 132 p., 1 sheet, scale 1:1,000,000.
Maddren, A.G., 1909, Gold placers of the Ruby Creek district: U.S. Geological Survey Bulletin 379-E, p. 229-233.
Maddren, A.G., 1910, The Innoko gold-placer district, Alaska, with accounts of the central Kuskokwim valley and the Ruby Creek and Gold Hill placers: U.S. Geological Survey Bulletin 410, 87 p.
Mertie, J.B., Jr., 1936, Mineral deposits of the Ruby-Kuskokwim region, Alaska: U.S. Geological Survey Bulletin 864-C, p. 115-245.
|Reporters||C.E. Cameron (Alaska Division of Geological and Geophysical Surveys)|
|Last report date||3/22/2000|