Rough and Tough; Reeve and Thompson; Ruff and Tuff Mine, Prince William Sound Mining District, Valdez-Cordova Census Area, Alaska, USAi

Regional Level Types
Rough and Tough; Reeve and Thompson; Ruff and Tuff Mine	Mine
Prince William Sound Mining District	Mining District
Valdez-Cordova Census Area	Census Area
Alaska	State
USA	Country

Location: This mine is 3.6 miles west of Mount Cameron on the southwest side of a nunatak in the eastern part of Columbia Glacier (Pickthorn, 1982, sheet 1); it is at an elevation of about 2,300 feet in the NW1/4 section 2, T. 8 S., R. 9 W., of the Copper River Meridian. This mine is located to within one-quarter mile. It is locality 1 of Cobb and Matson (1972) and locality 1 of Winkler and others (1981 [OFR 80-892-B]).
Geology: Gold-bearing quartz veins cut metaflysch of the Valdez Group and a Tertiary granitic plug at this locality (Smith, 1937, 1939). The quartz fills gashes in the granitic rock and surrounding hornfelsed metagraywacke. The veins contain sulfide minerals common to other gold-bearing quartz veins in the area; arsenopyrite and pyrite (Smith, 1937). Open cuts and at least 372 feet of underground workings explored the deposit (Jansons and others, 1984). Several tons of ore were recovered from open cuts and processed. The total production is 76 ounces of gold and 20 ounces of silver (Jansons and others, 1984). The U.S. Bureau of Mines collected seven chip samples from this area that contained 0.18 ppm to 2.52 ounces of gold per ton and 0.3 ppm to 0.89 ounce of silver per ton; a grab sample contained 14 ppm gold and 3.3 ppm silver. Eight other samples from this area contained up to 9.0 ppm gold (Pickthorn, 1982). These veins are probably similar to other gold-bearing quartz veins cutting metaflysch of the Valdez Group in the southern Valdez quadrangle. Data summarized by Goldfarb and others (1997) show that gold-bearing quartz veins in the Valdez Group commonly contain pyrite, arsenopyrite, carbonate minerals, chlorite, and white mica and formed from water-rich fluids with 5 to 15 mole percent CO2 and significant amounts of CH4, N2, and H2S. The vein-forming fluid salinities were less than 8 percent, vein formation temperatures ranged from 225 to 375 degrees centigrade, and emplacement depths varied from 3 to 10 kilometers. The vein-forming fluids were produced by metamorphic devolatization reactions. Radiometric dating indicates that the veins formed from 57 to 49 Ma (Goldfarb and others, 1997, p. 171), when deep parts of the accreted Valdez Group flysch underwent high-grade metamorphism and partial melting (Hudson, 1994).
Workings: Open cuts and at least 372 feet of underground workings explored the deposit (Jansons and others, 1984).
Age: Radiometric dating indicates that the gold-bearing quartz veins in the Valdez Group formed from 57 to 49 Ma (Goldfarb and others, 1997, p. 171), when deep parts of the accreted Valdez Group flysch underwent high-grade metamorphism and partial melting (Hudson, 1994).
Alteration: Country rocks to gold-bearing quartz veins in Valdez Group metaflysch can be variably silicified, carbonitized, and sericitized (Goldfarb and others, 1997).
Production: Several tons of ore were recovered from open cuts and processed. The total reported production is 76 ounces of gold and 20 ounces of silver (Jansons and others, 1984).

Commodities (Major) - Au; (Minor) - Ag
Development Status: Yes; small
Deposit Model: Low-sulfide Au-quartz veins (Cox and Singer, 1986; model 36a)

Other Databases

Link to USGS - Alaska:	VA097

Other Regions, Features and Areas containing this locality

References