Location: The Alaska-Juneau Mine is at an elevation of 1,000 feet, on the southwest side of Silverbow Basin, 2.5 miles east-southeast of Mt. Juneau and 1 mile north of Gastineau Peak. It is near the northeast corner of section 19, T. 41 S., R. 68 E. of the Copper River Meridian. The location is accurate. References to the Alaska-Juneau Mine commonly include the Ebner Mine (JU149), the Groundhog Mine (JU169), and the Perseverance Mine (JU168).
Geology: The Alaska-Juneau Mine (AJ, A-J), was discovered by Joe Juneau and Richard Harris in 1880 and comprises four separate ore bodies: the Ebner ore body (JU149); the North and South orebodies; and the Perseverance orebody (JU168). The mine operated from 1883 to 1944, when labor shortages and rising prices forced the mine to stop operations. The total production from the Alaska-Juneau Mine is approximately 3.5 million ounces of gold, 1.9 million ounces of silver, and 40.2 million pounds of lead (Redman and others, 1989). Of that total, the Alaska-Juneau North and South orebodies account for over 88 million tons of ore that produced 2.8 million ounces of gold and nearly 1.9 million ounces of silver; the Perseverance Mine (JU168) accounts for over 500,000 ounces of gold and over 480,000 ounces of silver; while the Ebner Mine (JU149) accounts for over 50,000 ounces of gold. The deposit was mined by modified block-caving and hand-sorting. There are 93.7 miles of underground workings on 15 levels that extend from 1000 feet below sea level to 2,800 feet above sea level. When combined with the Perseverance Mine, the total amount of underground workings is nearly 120 miles. From 1986 to 1988, Echo Bay Mines renovated the Sheep Creek Tunnel (JU177), completed a 2,000 foot decline to the AJ 4 level, and drove 1,100 feet of new workings in the Perseverance Mine (Redman and others, 1989). Approximately 360,000 feet of underground and surface core drilling was completed by Echo Bay Mines between 1986 and 1997. Using a sublevel caving mining model, Echo Bay Mines Ltd. calculated an indicated and inferred resource for the Alaska-Juneau Mine of 89 million tons with an average grade of 0.05 ounce of gold per ton (L. Miller, personal comm., 2001). The Alaska-Juneau deposit is a system of sulfide-bearing, auriferous, quartz-ankerite veins in the structurally lowest portion of the Perseverance Slate, an Upper Triassic unit of carbonaceous and graphitic, quartz-sericite phyllite, schist, and black slate, with minor carbonaceous limestone and numerous sill-like lenses of amphibolite or metagabbro (Miller and others, 1992; Light and others, 1989). The vein system is more than 6 kilometers in strike length, 700 meters in vertical extent, and is confined to the lowest 100 meters of the Perseverance Slate. The system comprises numerous veins, veinlets, stringers and stockworks; individual veins range from a few centimeters to over 1 meter thick. The veins are 95 percent quartz, with subordinate ankerite, pyrrhotite, galena, sphalerite, electrum, arsenopyrite, pyrite, and native gold. Approximately 90 percent of the gold is free-milling (Light and others, 1989; Twenhofel, 1952). The Alaska-Juneau Mine was one of the major gold producers in the Juneau Gold Belt. The belt consists of more than 200 mesothermal quartz-vein prospects and mines, which produced nearly 7 million ounces of gold (Miller and others, 1994). The structural grain of the belt is defined by a northwest-striking, moderately to steeply northeast-dipping, penetrative foliation that developed between Cretaceous and Eocene time (Miller and others, 1994).
Workings: The deposit at the Alaska-Juneau Mine (AJ, A-J), was discovered by Joe Juneau and Richard Harris in 1880 and comprises four separate ore bodies: the Ebner ore body (JU149); the North and South orebodies; and the Perseverance orebody (JU168). The mine operated from 1883 to 1944, when labor shortages and rising prices forced the mine to stop operations. There are 93.7 miles of underground workings on 15 levels that extend from 1000 feet below sea level to 2,800 feet above sea level. When combined with the Perseverance Mine, the total amount of underground workings is nearly 120 miles. During 1986-1988, Echo Bay Mines renovated the Sheep Creek Tunnel (JU177), completed a 2,000 foot decline to the AJ 4 level, and drove 1,100 feet of new workings in the Perseverance Mine (Redman and others, 1989). Approximately 360,000 feet of underground and surface core drilling was completed by Echo Bay Mines between 1986 and 1997.
Age: 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).
Alteration: Alternation consists of hydrothermal biotite, ferroan dolomite, and sericite; chlorite and albite partly replace amphibolite( Miller and others, 1992). The alteration has been traced with decreasing intensity as much as 1 kilometer from the Alaska-Juneau mine. Inward from its periphery, magnetite, then ilmenite and magnetite, are replaced by pyrrhotite (Miller and others, 1992; Newberry and Brew, 1987).
Production: The total production from the Alaska-Juneau Mine is approximately 3.5 million ounces of gold, 1.9 million ounces of silver and 40.2 million pounds of lead (Redman and others, 1989). Of that total, the Alaska-Juneau North and South orebodies account for over 88 million tons of ore that contained 2.8 million ounces of gold and nearly 1.9 million ounces of silver; the Perseverance Mine (JU168) accounts for over 500,000 ounces of gold and over 480,000 ounces of silver; while the Ebner Mine (JU149) accounts for over 50,000 ounces of gold production. The Alaska-Juneau deposit was mined by modified block-caving and hand-sorting.
Reserves: Using a sublevel-caving mining model, Echo Bay Mines Ltd. calculated an indicated and inferred resource for the Alaska Juneau mine of 89 million tons of material with an average grade of 0.05 ounce of gold per ton.

Commodities (Major) - Ag, Au, Pb; (Minor) - Cu, Zn
Development Status: Yes; large
Deposit Model: Low-sulfide Au-quartz vein (Cox and Singer, 1986; model 36a)

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Mineral List

ⓘ 'Tetrahedrite Subgroup'

11 valid minerals.