The deposit at the Ebner Mine was discovered in 1880. The mine was developed by nearly 11,000 feet of underground workings including the 3,500-foot Ebner Tunnel which was rehabilitated by Echo Bay Mines in 1987. The mine produced an estimated 32,000 ounces of gold and over 1,000 ounces of silver between 1889 and 1907, and 165,750 tons of ore with an average of 0.1 ounce gold per ton between 1925 and 1930. There was some gold production prior to 1898 but accurate production records are not available. The mine was acquired by the Alaska-Juneau Mining Co. in 1923. It currently (2001) is referred to as the Ebner orebody and represents the northern extension of the Alaska-Juneau Mine (JU165). The Ebner orebody was explored extensively by Echo Bay Mines in the late-1980s and 1990s. The U.S. Bureau of Mines has estimated that it contains a reserve of 300,000 tons of ore with an average of 0.07 ounce of gold per ton (Redman and others, 1989). The Ebner mine and the Alaska-Juneau mine are in the structurally lowest portion of the Perseverance Slate, a Upper Triassic unit that consists of 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 deposit is a system of quartz veins more than 6 kilometers in strike length, and 700 meters in vertical extent. The quartz-vein system is restricted to the lower 100 meters of the Perseverance Slate. The quartz-vein system is made up of numerous veins, veinlets, stringers and stockworks; individual veins vary from a few centimeters to over 1 meter thick. The Ebner veins are 95 percent quartz, with subsidiary ankerite, pyrrhotite, pyrite, chalcopyrite, and native gold. Approximately 90 percent of the gold is free-milling (Light and others, 1989). Hydrothermal alteration associated with the emplacement of the quartz veins formed biotite, ferroan dolomite and sericite as well as some chlorite and albite in the amphibolite. 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, 1988).