Vindicator Mine, Popof Island

Vindicator Mine, Popof Island

by | Mar 24, 2021

Vindicator is a historical beach placer mine on the western shore of Popof Island between Sand Point and Red Cove, about 260 miles (419 km) northeast of Dutch Harbor and 67 miles (108 km) southwest of Perryville, Alaska. Popof Island is about 9 miles (14.5 km) long and 6 miles (10 km) wide and adjacent to and separated from Unga Island by Popof Strait. Popof is a Russian proper name, often written Popov or Popoff. The island was originally named Popovskoi by Captain Mikhail Tebenkov, and shown as Popof Island on U.S. Bureau of Fisheries charts in 1890. The Vindicator prospect is in the Alaska Peninsula Mining District.

The geology of the Alaska Peninsula region consists of two main orogenies that extend for most of its length. The northwestern belt is about 35 miles (56 km) wide near the Ugashik Lakes but is absent on the western end of Unimak Island, it is predominantly unconsolidated Quaternary silt, sand, and gravel. The southeastern belt, which includes the offshore islands, is composed mainly of Mesozoic and Cenozoic sedimentary and volcanic rocks and Tertiary granitic plutons. Heavy minerals are released from these plutons by weathering processes and are slowly washed downslope, becoming concentrated in stream and beach gravels. Minerals that form placer deposits have high specific gravity and are chemically resistant to weathering such as gold, silver, platinum, cassiterite, magnetite, chromite, ilmenite, rutile, native copper, zircon, monazite, and various gemstones.

The Vindicator prospect is the only placer deposit on the Alaska Peninsula region for which there is a production record, although beach mining was reported on Unga Island in 1911 but did not identify where on the island or give any idea of the success of the venture. The Vindicator beach placer produced about 580 ounces (16.4 kg) of gold that was taken out with rockers in 1904 and 1905 from a belt about 0.75 miles (1.2 km) long. All the recovered gold was from below mid-tide level and most was found around large boulders near the low-tide line. Small-scale mining was reported here in each of several years before World War I, but there is no record of more recent activity. The source of the gold is likely from nearby lodes in intensely altered andesite. Read more here and here. Explore more of Vindicator here:

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This ‘warming stripe’ graphic is a visual representation of the change in global temperature from 1850 (top) to 2022 (bottom). Each stripe represents the average global temperature for one year. The average temperature from 1971-2000 is set as the boundary between blue and red. The color scale goes from -0.7°C to +0.7°C. The data are from the UK Met Office HadCRUT4.6 dataset. 

Credit: Professor Ed Hawkins (University of Reading). Click here for more information about the #warmingstripes.

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