One low tech method for gold recovery in rocky streams in Colchis (Georgia) was to secure a sheepskin on the rocky bottom. The gold being heavier would be captured by the wool while other debris would mostly wash over the sheepskin. After a time they would take the sheep skin and dry it and recover the captured gold dust and flakes. (I assume by beating it out and scraping the wool off and incinerating it.)
There was a National Geographic article about Jason and the Golden Fleece that showed a picture of a fleece in a shallow stream but I cant find it. (A pre internet article!Maybe 30-40 years ago. )
A modern analogue involve portable panning machines that have a piece of rug to capture gold dust when you are sluicing.
