Why do you want to use a sluice box in the first place? You want to find gold right? Well, in order to get more gold in the bottom of your sluice box, you need to understand how they work. Sluice boxes work because of gravity. Gravity is what traps the gold in your sluice, and the entire concept of a sluice box is based on how gold is found naturally in stream and river beds.
A long time ago, a gold prospector put two and two together. He noticed that he was finding more gold in the deeper spots of his favorite creek. In Winter, the creek would freeze over, and in Spring when all of the ice from Winter melted, his favorite creek would swell and overflow the banks. When this happened, when the water flowed at the right speed, it would pick up gold and move it down the creek. A combination of shallow water and a fast moving current would carry all of the gold down stream.
The gold had become magically suspended in the moving water, but when the water slowed down, the gold would fall out of suspension and settle on the creek bed. This very same prospector started to notice that he would find more gold in the deep spots of the creek. The fast flowing water would slow down when it got deeper.
Deep holes in the creek bed would cause the water to slow down and the gold would fall out of suspension. So he started eyeballing the creek and anywhere he saw the creek creating some back flow, he started finding gold with his pan. He also noticed that eddies were also a good source for gold.
Here is a little bit of info for you in case you don’t know what an eddy is. An eddy happens when fast flowing water passes over a submerged object. The submerged object causes the water to flow in the opposite direction for a short period of time. This reverse flow of water also causes gold to drop out of suspension.
Like other early prospectors, this prospector had a bad case of gold fever. He would dream of ways to find more gold while he was sleeping. He would also come up with wild ideas for prospecting for gold while he laid in bed trying to go to sleep.
What if he could create a system that would create a series of eddies or back flow, and feed gold rich dirt right into this system? This is how the concept of the sluice box was born, and the very first sluice boxes were made completely from wood. The water would help make the wood swell, and it actually made the sluice box work better.
If you take a close look at a sluice box, you will see that there are riffles that run from side to side. They are positioned for just about the entire length of the sluice box. Any guesses as to what these riffles do?
If you guessed that they change the flow of the water and create small back currents or eddies, then you are right.
Water flows down the length of your sluice box. You feed gold rich pay dirt through the front, and the water pushes all of the dirt right through the sluice. The flowing water picks up the gold and carries it down the sluice box. Once it hits the riffles, they cause that disruption in current, and the gold falls out of suspension. I made this animated picture to give you a better idea of how a sluice box works. This is the view of the sluice box as if you were looking at a cross cut section of it.