Gold recovery from gem gravel

Abstract

The combination of gold's relative scarcity and its elegant beauty has made it a very valuable commodity throughout the history of humanity. It is much evident that Sri Lanka is processing placer type secondary gold occurrences scattered with most of the alluvial gem gravel deposits in many areas. Unfortunately discards after panning for gem stones which contain finer particles of gold together with sand are thrown away as waste or sold out as a substitute to river sand. Therefore, it is important to find methods of recovering gold from gem gravel. In this study, Physical separation methods such as Table separation and Jig concentration were basically used for gem gravel as well as stream bed sediments from several parts of the country. After samples (about 300Kg) were processed, we were able to concentrate 71.2mg of gold particles and a relatively high amount of heavy minerals like Garnet, Rutile, Ilmenite, etc... Though the presence of gold in placer deposits exhibits relatively a low concentration, the high production cost in gold industry (630$ per ounce) elsewhere makes it a cheaper method to gold from gem gravel as a by-product of gem mining.