By A. H. KOSCHMANN and M. H. BERGENDAHL - USGS 1968
Click here for the Principle Gold Producing Districts of the United States Index
In the Alaska Peninsula, which forms the Southwestern Alaska region, only the Unga district contains commercial gold deposits of any magnitude. There has been scattered production from the Kodiak area, where lodes and beach placers were mined on a small scale, but more than 90 percent of the total production has come from Unga. Total recorded production for Southwestern Alaska through 1959 is 112,570 ounces, of which 108,000 ounces is of lode origin and 4,570 ounces is from placers.
UNGA DISTRICT
Unga is an island, one of the Shumagin Group, between lat 55°10' and 55°23' N. and long 160°30' and 160°50' W.
Almost the entire production of this district is attributed to the Apollo Consolidated mine which began production in 1891 and by 1904 yielded between $2 and $3 million (Martin, 1905, p. 100). Production decreased markedly after 1905 and ceased after 1922. Total production through 1959 was 107,900 ounces, all of lode origin.
The country rock is andesite and dacite believed by Becker (1898, p. 83) to be Miocene or younger and by Martin (1905) to be somewhat older than Miocene. Sedimentary rocks that range in age from Oligocene to Pliocene (MacNeil and others, 1961, p. 1802) are also present on Unga Island, but their relations with the igneous rocks cannot be determined from the published literature. Becker (1898, p. 84) described the deposit as a reticulated vein— a zone of fractures that was mineralized. The wall-rocks are much altered and have been replaced by chlorite and pyrite. Gangue minerals are sugary quartz with some calcite, and the ore minerals are free gold, pyrite, galena, sphalerite, chalcopyrite, and native copper (Becker, 1898, p. 83).
