Abstract: The present invention provides for a device and process for extracting heavy particles from lighter particles. The inventive device uses a unique riffle action, causing separation of heavy mineral from waste material, in combination with centrifugal force to retain the separated minerals in the concentrator. The concentrator processes a wide range of particle size feed for the extraction of heavy minerals. The device and process of the invention can extract a great percentage of very fine particles, as well as coarser particles. The machinery of the process can be installed in a roadworthy trailer for delivery and use at the excavation site.

Abstract: The present invention relates to a method of extracting gold from placer gravel. Whereas conventional techniques are relatively effective in the processing of coarse gold particles, i.e. plus ten mesh tyler, the present invention finds application in recovery of gold particles of all sizes from submicroscopic through coarse nuggets larger than ten mesh tyler. A rotating sluice box uses centrifugal force to enhance the sluicing process, and a centrifugal amalgamator then extracts gold from the concentrate thus produced, under centrifugal force. Gold is removed from the mercury by conventional techniques.