|Quadrangle map, 1:250,000-scale||MD|
|Quadrangle map, 1:63,360-scale||A-6|
|Nearby scientific data||Find additional scientific data near this location|
|Location and accuracy||This prospect is located on a southeast trending spur extending from VABM Side, at an elevation of 1,500 feet (457 m) in Section 31, T. 26 S., R. 16 E., of the Kateel River Meridian. The reporter visited the site in 1984.|
Mineralization at the Win prospect consists of polymetallic-sulfide and quartz-cassiterite mineralized vein and breccia vein systems within a quartz-tourmaline (dravite)-altered hornfels aureole that appears to be related to a small felsic stock and related dikes. Host rocks for the veins and vein breccias are lithic sandstone and siltstone of the Upper Cretaceous Kuskokwim Group (Bundtzen and Miller, 1997); age of mineralization is inferred to be Late Cretaceous based on 70.0 Ma age of nearby Cloudy Mt. intrusion (Moll and others, 1981). The intrusions are calc-alkalic, high Ca, low K, biotite rich, magnetite-bearing, oxidized garnet bearing dacite and granite porphyry (Burleigh, 1992). Mineralization in the hornfels covers a diffuse 1.25 square mile (3.2 square km) area, mainly south of the intrusive center. Mineralized veins and breccia zones exhibit a pronounced N 65 to 75 W trend, coincident with several regional faults in the immediate area (Patton and others, 1980). Virtually all significant mineralization occurs in hornfels and not in intrusives.An extensive sampling program yielded many high grade samples of polymetallic mineralization (Burleigh, 1992, BMOFR 92-92). One 7.75 foot (2.4 m) channel sample across a breccia vein contained 18.82 ounces/ton silver and 6.97 percent tin. Additional sampling showed values as high as 94.63 ounces/ton silver, 46.38 percent tin, 926 ppm bismuth, 0.36 percent copper, 1,699 ppm niobium, 5.00 percent antimony, 0.77 percent zinc, and 390 ppm selenium. Niobium values have a high correlation coefficient with tin at the Win prospect.
|Geologic map unit||(-155.883359532523, 63.2003831016535)|
|Mineral deposit model||Tin polymetallic vein (Cox and singer, 1986; model 20b).|
|Mineral deposit model number||20b|
|Age of mineralization||Late Cretaceous (inferred) based on 70.0 Ma age of nearby Cloudy Mt. intrusion (Moll and others, 1981). Specific age of the deposit is unknown.|
|Alteration of deposit||Tourmaline-quartz-sericite in felsic intrusive rocks; quartz-tourmaline-sphene in hornfels.|
|Workings or exploration||Duval Corporation trenched several veins at the Win prospect in the 1970s and early 1980s. Anaconda Minerals followed up with additional trenching and sampling in 1983. Online Exploration Services conducted surface sampling and an airborne geophysical survey of the Win prospect in 1997. An extensive sampling program conducted by the U.S. Bureau of Mines (Burleigh, 1992; BMOFR 92-92) yielded many high grade samples of polymetallic mineralization. One 7.75 foot (2.4 m) channel sample across a breccia vein contained 18.82 ounce/ton silver, and 6.97 percent tin. Additional sampling showed values as high as 94.63 ounce/ton silver, 46.38 percent tin, 926 ppm bismuth, 0.36 percent copper, 1,699 ppm niobium, 5.00 percent antimony, 0.77 percent zinc, and 390 ppm selenium. Niobium positively correlates with high tin values at the Win prospect. Anomalous gold has also been detected (Jim Adler, personal communication, 1998).|
|Indication of production||None|
|Reserve estimates||Despite widespread high grade mineralization, reserves have not been calculated, and there has been no drilling recorded as of 1997.|
Additional commentsSee: Won - South (MD024), Won - North (MD021), Cloud (MD059), and Gemini (MD023) prospects.
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.
Burleigh, R.E., 1992, Examination of the Win tin prospect, west-central Alaska: U.S. Bureau of Mines Open-File Report 92-92, 23 p.
Moll, E.J., Silberman, M.L., and Patton, W.W. Jr., 1981, Chemistry, mineralogy, and K-Ar ages of igneous and metamorphic rocks of the Medfra quadrangle, Alaska: U.S. Geological Survey Open-File Report 80-811-C, 15 p., 2 sheets, scale 1:250,000.
|Reporters||Bundtzen, T.K. (Pacific Rim Geological Consulting)|
|Last report date||6/3/1998|