|Main commodities||Ag; Au; Cu|
|Other commodities||Bi; Th; U; W|
|Ore minerals||azurite; bismuth; bornite; chalcocite; chalcopyrite; chrysocolla; electrum; gold; malachite; scheelite; unidentified u/th minerals|
|Gangue minerals||calcite; diopside; epidote; garnet; limonite; quartz; sericite; siderite; tremolite; zeolite|
|Quadrangle map, 1:250,000-scale||MD|
|Quadrangle map, 1:63,360-scale||A-4|
|Nearby scientific data||Find additional scientific data near this location|
|Location and accuracy||The Whalen Shaft is about 0.5 mile northeast of the center of section 24, T. 26 S., R. 21 E., on the ridge at the head of Rudy Creek. It is near the 'Glory Hole' shown on the 1:63,360-scale U.S. Geological Survey topographic map. The location is accurate.|
Mineralization was first staked in the area in 1917 and was mined intermittently from 1918 to 1964, notable by the Yukon-Treadwell company and by E.M. Whalen from several shafts, open pits, trenches, and a glory hole (Mertie, 1936; Herreid, 1966, Wallis and Rennie, 2005). The total production during this period is estimated to be 42,200 ounces of gold, 11,281 ounces of silver, and 41,400 pounds of copper from ore that averaged about 1.5 ounce of gold per ton. During this period, most of the mining took place here and about a mile to the north in the vicinity of Crystal Gulch (MD062); together they were usually referred to as the Nixon Fork Mine and their production aggregated. Much of the production during this period probably came from the Whalen Shaft area.There has been almost continuous exploration and considerable mining in the vicinity by several companies since 1984 but most of it has been concentrated in what is now usually called the Nixon Fork Mine (MD062) near Crystal Gulch, about a mile to the north. The several companies who have worked in the area undoubtedly have done some work in the Whalen Shaft area and it is noted in passing in several of the reports of their work. However little detail is available for the Whalen Shaft area specifically. The geology and mineralization is also similar to that at the better-known Nixon Fork Mine (MD062). The mineralization at the Nixon Fork Mine consists of several classic gold-copper, epiodote-diopside-garnet skarn deposits, generally within 10 to 150 meters of the periphery of a Cretaceous (68 to 70 Ma) quartz monzonite to granodiorite stock about 3 by 5 kilometers in size (Moll and others, 1981; Bundtzen and Miller, 1997, Wallis and Rennie, 2005). The Whalen Shaft is on the southern periphery of this stock. The stock intrudes the Ordovician Telsitna Formation, a 2,000-meter-thick sequence of limestone and dolomite, and Cretaceous calcareous sandstone and shale. Both the quartz monzonite and the host rocks are cut by late quartz-feldspar and quartz porphyry dikes. The orebodies are irregular and complex, often with branching arms, but are roughly pipelike, dip steeply, and follow or parallel the border of the intrusion at depth. In plan the orebodies typically are about 4 meters by 20 to 30 meters in area and extend down dip for several hundred meters. They are typically associated with epidote-diopside-garnet skarn near carbonate rocks or hornfels near sandstone and shale. Both exoskarn and endoskarn are present. Most of the ore minerals and skarn occur in exoskarn 10 to 30 feet into the marble front. Minor mineralized endoskarns occur within satellite bodies of quartz monzonite; however, most of this mineralization is not ore grade. The main ore minerals are pyrrhotite, chalcopyrite, pyrite, and native gold; minor bornite and chalcocite are known The quartz monzonite is sericitized and argillized near the mineralization and some of the ore bodies are oxidized up to a depth of 160 meters.
|Geologic map unit||(-154.771922733563, 63.215791737552)|
|Mineral deposit model||Cu-Au skarn (Cox and Singer, 1986; model 18b).|
|Mineral deposit model number||18b|
|Age of mineralization||Late Cretaceous based on 68 to 70 Ma isotopic age of monzonite adjacent to the skarn ore bodies.|
|Workings or exploration||The Whalen Shaft was driven to an unknown depth, but not below the water table, which was at about 400 feet. A glory hole is nearby and probably other workings. Beginning in 1984, several companies have extensively explored and drilled in the area but almost all of that work has been concentrated about a mile to the north at what is now called the Nixon Fork Mine (MD062). Some of the recent exploration undoubtedly extended to the vicinity of the Whalen Shaft as it is part of the same property. But other than mentioning it in passing, no detail is available.|
|Indication of production||Yes|
|Production notes||Mineralization was first staked in the area in 1917 and was mined intermittently from 1918 to 1964, notable by the Yukon-Treadwell company and E.M. Whalen, from several shafts, open pits, trenches, and a glory hole (Mertie, 1936; Herreid, 1966, Wallis and Rennie, 2005). The total production during this period is estimated to be 42,200 ounces of gold, 11,281 ounces of silver, and 41,400 pounds of copper from ore that averaged about 1.5 ounce of gold per ton. During this period, most of the mining took place here and about a mile to the north in the vicinity of Crystal Gulch; together they were usually referred to as the Nixon Fork Mine and their production aggregated. Probably much of the production during this period came from the Whalen Shaft area.|
Bundtzen, T.K., and Miller, M.L., 1997, Precious metals associated with Late Cretaceous-early Tertiary igneous rocks of southwestern Alaska, in Goldfarb, R.J., and Miller, L.D., eds., Mineral Deposits of Alaska: Economic Geology Monograph 9, p. 242-286.
Fire River Gold, 2010, Nixon Fork overview: http://www.firerivergold.com/s/NixonFork.asp (as of March 2, 2010).
Freeman, Larry, 1996, A progress report on the Nixon Fork underground gold mine, McGrath-McKinley district, Alaska [abs]: Abstract preprint of the 15th Biennial Conference on Alaskan Mining, Alaska Miners Association, Fairbanks, Alaska, p. 36.
Herreid, G.H., 1966, Geology and geochemistry of the Nixon Fork area, Medfra quadrangle, Alaska: Alaska Division of Mines and Minerals Geologic Report 22, 34 p., 1 sheet, scale 1:40,000.
King, H.D., Risoli, D.A., Cooley, E.F., O'Leary, R.M., Speckman, W.A., Speisman, D.L., and Galland, D.W., 1980, Final results and statistical summary of analyses of geochemical samples from the Medfra quadrangle, Alaska: U.S. Geological Survey Open-File Report 80-811F, 134 pages.
Martin, G.C., 1922, Gold lodes in the upper Kuskokwim region: U.S. Geological Survey Bulletin 722-E, p. 149-161.
Mertie, J.B., Jr., 1936, Mineral deposits of the Ruby-Kuskokwim region, Alaska: U.S. Geological Survey Bulletin 864-C, p. 115-245.
Newberry, R.J., Allegro, G.L., Cutler, S.E., Hagen-Levelle, D.D., Adams, D.D., Nicholson, L.C., Weglarz, T.B., Bakke, A.A., Clautice, K.H., Coulter, G.A., Ford, M.J., Myers, G.L., and Szumigala, D.J., 1997, Skarn deposits of Alaska, in Goldfarb, R.J., and Miller, L.D., eds., Mineral Deposits of Alaska: Economic Geology Monograph 9, p. 355-395.
Patton, W.W. Jr., Moll, E.J., Dutro, J.T., Jr., Silberman, M.L., and Chapman, R.M., 1980, Preliminary geologic map of the Medfra quadrangle, Alaska: U.S. Geological Survey Open-File Report 80-811-A, one sheet at 1:250,000 scale.
Postle, John, Scott, Kevin, and Wallis, C.S., 2006, Technical report on the Nixon Fork project Alaska, U.S.A.: Technical report prepared for St Andrew Goldfields Ltd., 98 p. (posted on www.sedar.com, October 4, 2006)
St Andrew Goldfields Ltd., 2009, Nixon Fork Mine: was available on the Internet as of March 11, 2009 but as of early 2010 it has been deleted.
Wallis, C.S., and Rennie, E.W., 2005, Technical report on the Nixon Fork project, Alaska: Technical Report prepared for St. Andrew Goldfields Ltd., 78 p. (posted on www.sedar.com, October 4, 2006).
Wallis, C.S., Rennie, D.W., and Hendry, J.W., 2003, Report on the Nixon Fork project, Alaska: Technical Report prepared for St. Andrew Goldfields Ltd., 65 p. (posted on www.sedar.com, September 17, 2003).
|Reporters||Bundtzen, T.K. (Pacific Rim Geological Consulting); D.J. Grybeck (Contractor, U.S. Geological Survey)|
|Last report date||4/2/2010|