Dull And Stephens

Mine, Inactive

Alternative names

Gold King

Commodities and mineralogy

Main commodities Au
Other commodities Ag; Cu; Pb
Ore minerals arsenopyrite; chalcopyrite; galena; gold; pyrite; pyrrhotite
Gangue minerals quartz

Geographic location

Quadrangle map, 1:250,000-scale JU
Quadrangle map, 1:63,360-scale B-2
Latitude 58.4424
Longitude -134.5269
Nearby scientific data Find additional scientific data near this location
Location and accuracy This mine is at an elevation of 700 feet on the low ridge between Waydelich Creek and Lake Creek. It is 1 mile northwest of Auke Lake, just northeast of the center of section 15, T. 40 S., R. 65 E. of the Copper River Meridian. The location is accurate.

Geologic setting

Geologic description

The Dull and Stephens Mine was discovered in 1906. It was developed by a 150-foot adit, a 144-foot adit, a 199-foot adit, a 297-foot adit, and numerous trenches. The property produced 32 ounces of gold by sluicing overburden in 1909 and 1914. The deposit consists of several 1- to 2-foot- thick, northeast-trending, discontinuous quartz veins and irregular masses of quartz that dip steeply north. The veins are along the contact between phyllite and greenstone (in part volcanic breccia), and contain pyrite, arsenopyrite, pyrrhotite, galena, and traces of chalcopyrite and native gold (Knopf, 1912). U.S. Bureau of Mines samples contained a weighted average grade of 2.0 ppm gold over 1.8 feet (Redman and others, 1989).
This mine is in the Juneau Gold Belt, which consists of more than 200 auriferous quartz vein deposits that have produced nearly 7 million ounces of gold. These gold-bearing mesothermal quartz vein systems form a 160-km-long by 5- to 8-km-wide zone along the western margin of the Coast Mountains. The vein systems are in or near shear zones adjacent to west-verging, mid-Cretaceous thrust faults. The veins are hosted by diverse, variably metamorphosed, sedimentary, volcanic, and intrusive rocks. From the Coast Mountains batholith westward, the host rocks include mixed metasedimentary and metavolcanic sequences of Carboniferous and older, Permian and Triassic, and Jurassic-Cretaceous age. The sequences are juxtaposed along mid-Cretaceous thrust faults (Miller and others, 1994). The sequences are intruded by mid-Cretaceous to middle Eocene plutons, mainly diorite, tonalite, granodiorite, quartz monzonite, and granite. Sheetlike tonalite plutons emplaced just east of the Juneau Gold Belt and undeformed granite and granodiorite bodies that are emplaced farther to the east are between 55 and 48 Ma (Gehrels and others, 1991). The structural grain of the belt is defined by northwest-striking, moderately to steeply northeast-dipping, penetrative foliation that developed between Cretaceous and Eocene time (Miller and others, 1994). The majority of the veins in the Juneau Gold Belt strike northwest. Isotopic dates indicate that the auriferous veins in the Juneau Gold Belt formed between 56 and 55 Ma (Miller and others, 1994, Goldfarb and others, 1997).
Geologic map unit (-134.52867900874, 58.4420763499296)
Mineral deposit model Low-sulfide Au-quartz vein (Cox and Singer, 1986; model 36a)
Mineral deposit model number 36a
Age of mineralization Isotopic dates indicate that the auriferous veins in the Juneau Gold Belt formed between 56 and 55 Ma (Miller and others, 1994; Goldfarb and others, 1997).

Production and reserves

Workings or exploration The Dull and Stephens Mine was discovered in 1906. It was developed by a 150-foot adit, a 144-foot adit, a 199-foot adit, a 297-foot adit, and numerous trenches.
Indication of production Yes; small
Production notes The property produced 32 ounces of gold by sluicing overburden in 1909 and 1914.

References

MRDS Number A012018

References

Gehrels, G.E., McClelland, W.C., Samson, S.D., and Patchett, P.J., 1991, U-Pb geochronology of detrital zircons from a continental margin assemblage in the northern Coast Mountains, southeastern Alaska: Canadian Journal of Earth Sciences, v. 28, no. 8, p.1285-1300.
Goldfarb, R.J., Miller, L.D., Leach, D.L., and Snee, L.W, 1997, Gold deposits in metamorphic rocks in Alaska, in Goldfarb, R.J., and Miller, L.D., eds., Mineral Deposits of Alaska: Economic Geology Monograph 9, p. 151-190.
Miller, L.D., Goldfarb, R.J., Gehrels, G,E., and Snee, L.W., 1994, Genetic links among fluid cycling, vein formation, regional deformation, and plutonism in the Juneau gold belt, southeastern Alaska: Geology, v. 22, p. 203-206.
Reporters J.C. Barnett and L.D. Miller (Juneau, Alaska )
Last report date 12/15/2001