Public domain
Production. Copper. A closeup of a disc-type filter showing how the dried copper concentrate is broken by expansion of the filter and then discharged. This filter unit is at the Arthur plant of the Utah Copper Company
From the collection of Library of Congress. Free to download, adapt and use — no permission needed.
Credit lineProduction. Copper. A closeup of a disc-type filter showing how the dried copper concentrate is broken by expansion of the filter and then discharged. This filter unit is at the Arthur plant of the Ut. 1940-01-01. Feininger, Andreas, United States. Office Of War Information. Farm Security Administration/Office of War Information Collection, Library of Congress. Public domain.
