Placer Gold Recovery Methods By Michael Silva Special Publication 87

Placer Gold Recovery Methods By Michael Silva, Special Publication1986California Department of Conservation Division of Mines and Geology 1416 Ninth StreetSacramento, California 95814 ContentsIntroduction.......................................................................................................Pg. 1Concentration of Placer Gold Ore.....................................................................Pg. 2Small Scale Recovery Equipment.....................................................................Pg. 2   Gold Pan.........................................................................................................Pg. 2   Rocker............................................................................................................Pg. 3         Construction.............................................................................................Pg. 3         Assembly..................................................................................................Pg. 5         Operation..................................................................................................Pg. 5   Sluices............................................................................................................Pg. 6         Long Tom.................................................................................................Pg. 7         Dip-Box....................................................................................................Pg. 8   Shaking Tables...............................................................................................Pg. 8   Portable Processing Equipment......................................................................Pg. 9   Amalgamation................................................................................................Pg. 10Dry Placers........................................................................................................Pg. 10   Dry Washers...................................................................................................Pg. 10   Air Tables (Oliver Gravity Separator) ..........................................................Pg. 11Modern Recovery Equipment...........................................................................Pg. 12   Pinched Sluice Systems (Reichert Cone) ......................................................Pg. 12   Spiral Concentrators ......................................................................................Pg. 13         Rotating Spirals........................................................................................Pg. 15         Helixes.....................................................................................................Pg. 15   Jigs.................................................................................................................Pg. 16   Fine Material Separators................................................................................Pg. 20         Bartles-Mozley Separator........................................................................Pg. 20         Bartles CrossBelt Separator.....................................................................Pg. 21   Centrifugal Concentrators..............................................................................Pg. 21         Bowls.......................................................................................................Pg. 21         Knelson Concentrator..............................................................................Pg. 22Summary...........................................................................................................Pg. 22Operating Mines...............................................................................................Pg. 23   Hammonton Dredge......................................................................................Pg. 23   Hansen Brothers - Hugh Fisher.....................................................................Pg. 25         Bear River...............................................................................................Pg. 26         Greenhorn Creek.....................................................................................Pg. 26   TRI-R Engineering - Stinson Mine...............................................................Pg. 27Selected Annotated References........................................................................Pg. 29Appendix: List of Equipment Manufacturers and Suppliers...........................Pg. 31