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How to Make a River Gold Sluice

In the natural environment, dense grains rolling along a river bed concentrate just downstream of obstructions such as rocks and ridges. Miners prospecting for gold in running water take advantage of this tendency with sluices. These artificial riverbeds contain multiple obstructions, called riffles, in a short distance. A shovelful of sand and gravel, dumped in the top of a sluice and washed along its length by running water, will leave heavy particles behind the riffles just as in nature. A simple homemade sluice that can be built in an evening will allow an amateur prospector to process sand and gravel considerably faster than with a pan.

Things You'll Need

¾-inch exterior plywood
Circular saw or table saw
1½-inch deck screws
Power drill and bits
Scrap 2-by-4

Instructions

- 1
  Cut one strip of plywood 12 inches x 5 feet and two strips 5 inches x 5 feet.
- 2
  Screw the two 5-inch strips to opposite sides of the 12-inch piece to form a long, narrow trough.
- 3
  Set the saw bevel at 30 degrees and rip a strip of plywood 1½ inches wide and 8 feet long. Cut eight 12-inch lengths from this strip.
- 4
  
  The crosswise riffles cause turbulence in flowing water just like rocks and ridges in a natural stream.
  
  Attach a wooden strip crosswise within the trough18 inches from one end (the top), beveled side down so that it’s angled toward the bottom end. Attach the remaining strips at 6-inch intervals, tilted the same way, to make the riffles. Drill holes in the strips for the deck screws to avoid splitting the plywood. Save the extra strips to replace damaged riffles.
- 5
  Cut a scrap of 2-by-4 13½” long and attach its narrow edge to the bottom of the trough 6 inches from the top end. This makes a stand so the sluice rests on the riverbed tilted downstream.
- 6
  Position the sluice in a stream with the top end pointing upstream and empty a shovel of sand, gravel and dirt into the large space in the top end. Let the water wash the soil over the riffles. Carefully inspect the sediment trapped under the overhang of the riffles for particles of gold.

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