Around 1200 B.C., the Egyptians used unshorn sheepskin to mine for gold dust from the sands of the Black Sea. This practice is most likely the inspiration for the Golden Fleece."
Some miners in other parts of the world still use this method of getting there gold
as they don't have the equipment or they cant get the equipment to use, and they
have been using this method for many hundreds of years. http://www.argonauts-book.com/fleece-as-gold-mining.html