Sluice Box

Running a sluice box is simple and will greatly improve the amount of gold you can recover in a day of prospecting. If you are serious about gold prospecting, a sluice box will be a required piece of equipment for your prospecting tool chest. Sluice boxes can be purchased from a large variety of sources or because of their simple design, easily built by anyone with minor construction skills. To get started using your sluice box follow these simple operational guidelines.

Setting Up the Sluice Box: Once you have located a promising area of gold bearing gravel, walk along the stream bank and search for a good place to set up the sluice box. Ideally find a spot where the current is moving swiftly and carrying decent volumes of water. Once you find the spot, set your sluice box directly in the current so that the box is filled with water almost to the top of the trough. To test the current’s ability to carry gravel through the sluice, scoop up a handful of gravel from the creek bed and drop it into the upper end of the trough. If the current washes the lighter gravel down the trough within a matter of seconds, you have found a good location. Brace your sluice box so it doesn’t rock, by the time a couple of shovels of gravel are placed in your sluice should be secure.

Getting Started: Now you will want to “feed” your gold-bearing gravel into the upper portion of the sluice box in carefully measured amounts. Don’t, under any circumstances, dump a large amount of gravel into the sluice box all at one time. This will allow gold bearing gravel to fall out of the sides of the sluice box. The gravel must be fed at a pace that will not overload the riffles. If the riffles are overloaded you cannot see the top most “crest” of each riffle bar at all times, then you are feeding the gravel too fast. If this is happening reduce the amount of gold bearing ore you are feeding into the sluice. The use of a quarter to half inch classifier screen to prescreen material before dumping into the sluice box can save much time and effort. The cost for overloading a sluice box riffles is the loss of gold. Each time a new load of gravel is dumped into a sluice box with overloaded riffles, any gold in that gravel will wash right over the material that is clogging your riffles and out the discharge end of the box, and down the stream. So mind the sluice box.

Tending the sluice: Each time you dump a load of gravel into the sluice box check the riffle section for large waste rocks which may be too big to wash down and are hanging up. Remove these with your fingers immediately because these large rocks are affecting the flow of water through the sluice box. If a rock is lodged in the uppermost portion of the trough the washed out concentrate will merely settle in the next few riffles down. But if the wash out occurs at the lower end of the trough the concentrate may flow out of the sluice box altogether. One more thing, don’t forget to shovel away the tailings which will periodically build up at the discharge end of the sluice box. If you don’t the tailings will back up into the lower end of the sluice trough, burying some of your riffles.

Cleanup: Once the riffles have accumulated black sand in amounts extending more than halfway toward the next lower bar it is time to perform the “cleanup”. Using care, lift the sluice box from the current, keeping it as level as possible. Take it over to the bank and set it down on as level a spot. Gold has a tendency to work its way beneath the matting which often lies at the bottom of the trough. You may be surprised at the amount of “color” that can accumulate there. Check to see if there is any fine silt clinging to the bottom, rinse all of it into your concentrate bucket. Take out the riffle section of the sluice, exercising care not to disturb the gravel adhering to it. Roll up the matting which lines the bottom of the sluice box trough and thoroughly rinse off all the concentrate. This should be done with the matting safely contained in a large bucket or tub, so you don’t lose any of the concentrate. Rinse the riffle bars and the trough itself into the bucket, a lot of gold will work it’s way under the matting and may accumulate there.

Panning the Concentrate: At this point you will have a bucket of heavy black sand and gold. To get the gold out at this point you will want to use a small gold pan and work the fines down to the native gold. This is normally the most exciting part of the operation and can be done at night or even when you are back at home after your trip.