Treatment of Placer Deposits

Abstract

Alluvial, or placer, gold has been washed away by flowing water or carried by blowing wind. It has then been deposited along with earth, sand, gravel, and other transported matter, especially on river beds. Although there is no way of knowing exactly how long ago humans felt enamored of the shiny yellow metal, there is reason to presume that gold, specifically alluvial gold, has been known and appreciated for at least 12,000 years. The Egyptians knew how to melt gold and silver about 6,000 years ago, and records indicate that gravity concentration of gold was practiced around 4000 b.c.