Controlling Water in a Sluice Box

Too much water power through the sluice will create turbulence behind riffles. This will cause some of the heavier concentrated material be swept away out of the box. When this happens, gold recovery is also affected since the areas located behind the riffles are not calm as to allow a percentage of the finest pieces of gold to set. In these cases, you will notice that bailing is happening behind every riffle, but less material will set behind due to the increase of turbulence in the area. When there is too much speed in the flux of water you will notice that when shoveling the material inside the box, it will go through very quickly and it will not have time to make contact with the riffles.

All the aforementioned points will remain true when adjusting to the right amount of flux to the expansive metal riffle system. However, when using the system it is good to remember that your riffles are smaller, so it would not take too much speed of water to make it work properly. Generally, the amount and the right flux of water is that that makes materials move through the box jointly with shoveling. Since gold is around 6 times heavier than the average material that will go through the sluice, usually there is a margin of mistake if the speed is a little bit more than the one needed. 

Once you have the sluice box built and placed the right way it would be a good idea to move through the box a generous portion of material with gold contents and after that you should take some samples out of the remaining materials in the pan. If you do not find gold among these remaining materials some changes should be made.

Another test would be to mix some pieces of lead with the material, move it through the sluice and see were the pieces end. Sluice boxes process material better when feeding of the same is stable. Much material thrown inside the box at the same time tends to overcharge riffles and expulse concentrates. This would cause gold to go through the sluice box as if there were no riffles.

On the other hand, it is not a good practice to make it run volumes of water through the sluice box without having a regular augmentation of materials in it. This is due to the polishing action of the flux of water will continue concentrating the material already trapped in back of the riffles, and will cause heavier materials be washed outside the box.