A sluice box indeed is a great way of prospecting for gold. It’s small, lightweight enough to be carried around, and can speed up the gold recovery rate by 10 to 200 times depending on the exact situation. There is no doubt that having a sluice box is a great way of finding more gold and work through more material.
However, as with everything, there are some technicalities you must know to make the most out of your sluice box. If run recklessly, you risk losing a lot of the gold you have been digging so hard for.
So, how do you set up a sluice box? A sluice box should be set up in a creek or river with a steady flow of water, so that the lighter materials can get flushed out of the sluice box, while the heavier gold and black sands are trapped. As a general rule of thumb, it should slope around 5-7 degrees to function efficiently. To prevent the sluice box from floating away, you may place a heavy rock on top of it.
While this is the short and correct answer, there are some more details that are worth considering when setting up your very own sluice box. That’s exactly what you will learn in this article, but before, it really is necessary to have a brief look at how sluice boxes capture gold!
Table of Contents
How Does a Sluice Box Capture Gold? (Essential!)
A sluice box contains several traps across the length of its channel that are designed to disrupt the flow of water in various ways. This is primarily done to slow down the flow so that the gold drops to the bottom, or to create vortices of varying kinds that sort out the heavier materials.
Riffles
Riffles come in various forms, but the most common type is the Hungarian or Lazy L Riffle type. In short, it operates by the following main principle:
- The water flows over the riffles.
- The resulting slowdown of the water current causes heavy materials such as gold to drop behind the riffles. A so-called “Eddy zone” is created, which helps to capture the fine gold. The overhanging lip helps deposits to form right after the riffle.
The image below shows an example of this:
Mattings and Carpets
Sometimes very fine gold particles might escape the riffles. Due to this, many sluice boxes are equipped with some type of matting or carpet that is design to capture the gold as it slides along its surface.
One common type of matting is the so-called ” Miner’s moss”. It consists of woven fibers and as its name suggests, it resembles natural moss. Miners moss, as well as natural moss, often manages to catch the really fine gold, as it falls into the fibers and gets trapped.
With the basics of sluice boxes covered, let’s go on to the meat of the article!
How to Set Up a Sluice Box
Setting up a sluice box correctly isn’t hard, but still requires you to know some basics. For example, having too much water coming through the sluice will cause a lot of the gold to get flushed out, which is something we want to avoid.
With that said, let’s look closer at how to set up your sluice box correctly. To make it easier to follow, we have broken down the process into a couple of easy-to-follow steps:
Step 1: Find a spot with enough water flow
To operate as efficiently as possible, a sluice box requires a steady flow of water through the box. This means that you need to place it in a rather fast-moving stream or creek, to ensure that there is enough water to remove the lighter material.
If the stream isn’t flowing quickly enough, you can always build a funnel of rocks that are heavy enough to not be moved by the flow of water. Sometimes just placing a couple of rocks around the entrance of the sluice might do the trick, and provide just the extra water that is needed.
Tip: A nice trick when building your own funnel is to bring a sheet of thin plastic or a couple of rice bags, and use it to prevent the water from running through the barrier you just built.
Step 2: Level the sluice box and stabilize
Make sure that the sluice box is leveled sidewise. You want the flow of water to be even across the riffles and mattings to ensure optimum performance.
Lengthwise, the sluice box should be angled around 5-7 degrees to allow pebbles and other materials to pass through easily.
Another commonly used rule of thumb is that the sluice box should drop 1 inch for each foot of sluice. In other words, the lower end of a sluice box that’s 10-foot long should be 10 inches lower than the far upper end.
Once you have got the sluice set right, you might want to place a large rock on top of it, so that it doesn’t float away or move too much.
Now, one thing that confuses many is how much water they should have going through the sluice. Let’s look closer at this!
How much Water Should You Have Running Through the Sluice Box?
Having the right amount of water running through the sluice is critical. Too much, and you will have the fine gold running right through the sluice. Too little, and lighter materials will clog the riffles, rendering them useless.
In short, you should have enough water flowing through the sluice to keep it clean, and the riffles should not become buried under the sand. You should also ensure that the bed of the sluice box doesn’t get fully covered by sand. If there is white froth as the water flows over the riffles the flow is too violent and needs to be dampened.
Depending on the sluice box, the amount of water that is needed will vary. Having shorter riffles means that less water is needed to make them function properly, whereas higher riffles require more water.
Another rule of thumb to keep in mind that might be useful is to have the water flow at a rate that lets the lighter materials run through the sluice box in a few second’s time. Obviously, the exact number of seconds depends on the length of the sluice, but you get the idea. The lighter materials should move fairly quickly through the sluice!
When the water flow is right, the recovery rate of most sluice boxes will be really satisfactory. However, operating the device is a sensible manner will also have a big impact on the results you get.
Let’s take a look at how to operate and feed a sluice box to maximize the retention rate.
Operating and Feeding the Sluice Box
In order to retain as much gold as possible when using your sluice box, there are a couple of things you need to be aware of. To make it as easy as possible for you, we have provided clear instructions below:
Step 1: Classify Your Material
Before throwing gravel onto the sluice, you should classify the material. Basically, this means that you run the gravel through a net to remove all rocks and stones above a certain size.
Classifying the material is essential, as having too big pieces of rock in the sluice will disturb the flow of water, clog the sluice, and cause excessive wear on the riffles and mattings.
Typically you use one inch or a half-inch classifier when running a regular sluice box.
To classify, you just pour the material into the classifier. All the material that is smaller than the classifier size will fall through, while the larger pieces stay in the classifier.
If you are working with really dry material, you can just twist and turn the classifier to get the rocks clean from dirt and sand.
However, as soon as they are damp or humid, you will have to submerge the material into water, to ensure that any potential gold isn’t thrown away with the large rocks.
Once the rocks are clean, you just throw them away. If you are in nugget-rich grounds, you want to be careful not to throw away any nuggets in the process!
Step 2: Feed the sluice box
When feeding the sluice it’s important to be gentle and let the material stratify properly before adding more. This basically means that you should ensure that all the material is soaked and loosened by the water and is turned into a slurry. If the material is not stratified properly, the fine gold might just run straight through the sluice and back to the river.
Step 3: Work the concentrate
Now rinse the crevices and traps of the sluice and pour the concentrate into a bucket. If your sluice box is small enough to go into the bucket you could just fill it up with water and submerge the sluice into it. Use water to rinse the parts of the sluice that don’t go into the bucket, and take out the mattings and rinse them carefully as well.
The final step then is to separate the gold from the black sand. Most times you use a gold pan and swirl the material gently with some water in it. However, it’s worth noting that there are many methods available.
We recommend that you take a look at our complete guide to separating gold from black sand if you want to learn more about how to proceed from here!
Some additional valuable tips!
Don’t let the sluice run for too long without adding more material: As the material is captured in the sluice, the gold goes to the bottom of the sluice bed together with the black sands. If new material isn’t added for some time, there is a risk that enough heavy material will be removed to expose the gold, which then risks getting carried away with the stream of water.
If you know you aren’t going to feed the sluice for some time, divert the water from the sluice to avoid unnecessary losses!
Don’t empty the sluice too often: If you just follow the guidelines followed in this article, you can continue for long periods of time without emptying the sluice and lose no to very little gold. Not emptying the sluice too often is all about efficiency. If you let it run for longer, you will not waste your time on unnecessary cleanup.
Be careful with clay: Clay clogs that don’t break up as they travel through the sluice could cling on to gold and carry it with them. Make sure to break up any clay clogs and ensure that the gravel is washed carefully.
Unsure?: Test it for yourself!
If you don’t feel confident in having set up your sluice in a correct manner, test it for yourself! Just run through some gold-bearing material through the sluice, and then pan the tailings. If there is no gold to be found, you can rest assured that the sluice box is set up correctly.
Conclusion
A sluice box is a highly efficient gold recovery device that is used by beginners as well as experienced miners to speed up the recovery process.
The most critical aspect to keep in mind when setting up a sluice box is the amount and speed of the water that goes through it. However, to achieve a respectable retention rate you also need to ensure to not be reckless when feeding the sluice box. As you already know by now, this involves not dumping more material than can be soaked thoroughly, as well as not leaving the sluice box without new material for longer periods of time!
Happy Panning!
