Types of Gold Dredges

A gold dredge is a device that miners use in order to separate gold from gravel and dirt. Gold dredges have been in use for hundreds of years, and are still in wide use today. Several different types of dredges exist, each slightly modifying the general process. Should you be interested in mining for gold as either a hobby or for profit, it behooves you to become aware of the different types of dredges that are available.

  1. Surface Dredges

    • Surface dredges float upon the surface of the water. A suction hose pumps dirt and gravel up and into the sluice box, that is, the device which separates small particles of gold from other materials. More modern versions of this concept often feature multi-stage sluices, which are able to isolate smaller and smaller particles of gold.

    Underwater Dredges

    • Underwater dredges are less convenient to operate than surface dredges, and also lack the ability of a surface dredge to recover large amounts of gold. You must hold submersible dredges completely level while operating, and must also use them in significantly deep water, as they must be completely submerged in order to operate properly. They consist of a long tube with one side flared at a 45 to 60 degree angle. The dredge pumps water into the bend end at a high pressure, so that gravel and dirt is sucked in at the far end. A riffle tray catches the gold as the gravel runs through the dredge.

    Spoon Dredges

    • Spoon dredges were one of the first types of dredges, appearing near the end of the 19th century. They were quite simple in their design. Usually, they consisted of nothing but a leather bag wrapped around an iron loop connected to the end of a pole.

    Bucket Dredges

    • Bucket dredges, also called flume-sluice dredges, first appeared in 1868. They consisted of a line of buckets that would continuously scoop gravel from the bottom of a river. A wheel that turned with a river's current moved the buckets.

    Screen and Flume Dredges

    • Screen and flume dredges also employ buckets, but the buckets pour the gravel into a revolving screen that separates the larger gravel from the smaller. Sometimes, the screen is flat, called a "shaker." Its function is to break up the larger pieces of dirt and allow the finer particles to pass through.

    Combination Dredges

    • Combination dredges add a conveyor belt to the screen dredge. The belt carries the coarser materials off the boat while allowing the gold to pass through the screen.

    Table Stacker Dredges

    • Miners in harsher environments, such as Alaska, often used table stacker dredges. Buckets still carried gravel from the river bed and through a screen, but this time instead of a single sluice, the material would pass through a series of sluices stacked one atop the other. Gradually, the sluices separate the gold out.