As gold miners, we take advantage of the superior weight of gold to separate it from other materials. And while this works perfectly when it comes to separating light materials from the much denser gold particles, it becomes more and more challenging the heavier the materials we are working with. Once we find black sand, we have managed to concentrate the very heaviest materials, which sometimes means that we might have to abandon our original method in order to lose as little gold as possible in the next step.
So, how do you separate gold from black sand and make sure that as much gold as possible is retained?
Well, in order to separate gold from black sand you can use any of the following techniques:
- Gold Panning
- Blue Bowl
- Gold Cube
- Miller Table
- Magnets
Which technique suits you best depends on what type of material you are processing, as well as your ambition level.
In this article, we are going to look at the above-mentioned techniques and devices. We will also try to help you determine which technique suits you best, considering the type of material you are processing and your ambition level.
But before we delve into all this, we just want to touch on a really important topic!
Table of Contents
Saving Your Black Sand?
Many gold prospectors save their black sand if they deem it probable that it might contain some amounts of fine gold. Then, once they have gathered some larger amounts, they run it all through their extraction method of choice. Often this operation is carried out during the cold months of the year, when gold mining might not be a feasible or enjoyable experience.
So should you save your black sand as well? It really depends. If you are in gold-rich grounds, there could be merit in bringing home the black sand for further analysis. However, if you are just prospecting, you are generally looking for grounds rich in gold, and at that stage, your goal isn’t to extract gold, but to find good gold-bearing areas.
With this said, let’s go on to the real meat of the article!
Common Separation Methods
There are many ways available that you can go about to separate the gold from black sand. Some options are really cheap and simple, while others include the use of rather expensive equipment and gear.
However, it should be noted that a simple gold pan is a highly effective tool. If you are just starting out, there is generally no need to use the more advanced methods, since they tend to be costly and take some time to operate. And even if it means you lose some tiny amounts of gold, you might just be better off using your precious time to prospect more grounds.
However, a gold bowl (described below) could be a nice tool to have, since it’s really cheap, and is able to bring the really light gold to the light.
Important Tip!
When collecting really fine gold, and especially flat gold particles, you always risk having them floating away as they gain lift with the surface tension of the water. Due to this, when recovering fine gold, we always recommend you use some jet dry to break the surface tension.
With that said, let’s take a closer look at the most common and effective ways to separate gold from black sand!
1. Gold Panning
Recommended for: Any Prospector
The gold pan is perhaps the most versatile piece of equipment you can get your hands on, and is used for a wide range of purposes. In addition to prospecting in search of gold-rich grounds, many big-scale operators use gold pans to clean concentrates from bigger machinery, such as wash plants and dredges.
A gold pan works really well for separating the gold from the black sand and is used as the main cleaning method by many experienced miners. However, getting the really fine gold requires some proficiency, and might be hard for someone who is just starting out.
To not let go of any gold during the panning process, we recommend that you pan your concentrate in a tub. That way you can go over the material several times, and pick up those pieces you lost at the first attempt.
How to use a gold pan to separate gold from black sand
Once you have panned off most of the material, and just have around half a cup of material left in the pan, you do the following:
- Fill some water into the pan. Around one to two cups is enough.
- Amass all of the material towards the far end side of the pan and shake it. You want to make sure that the gold gets a chance to sink to the bottom before the next step.
- Then start to swirl the water gently around. Each time the swirling waterfront sweeps over the material, it should move the lighter materials, while the gold stays where it is. (See image)
- Then use a snuffer bottle to suck up the gold particles.
- Now, since some of the gold inevitably will blend with the black sand to some degree, you may redo step 2-4 a couple of times.
Extra Tip
Before you start swirling the pan, you could add one extra step in order to concentrate the gold further towards the edge where the water sweeps in over the material.
Just tap the edge of the gold pan against your hand in a rhythmic pattern. The video below makes a great job of explaining this method, so we will simply leave it here.
2. Blue Bowl
Recommended for: Any Prospector
The Blue Bowl is a really neat, inexpensive piece of equipment that does a phenomenal job of getting rid of the black sand. This is a great addition to anyone who owns a gold pan and is looking to find a more precise and effective method to extract those really tiny pecks of gold.
Here is how it works:
- Water comes in through the hose connection, and swirls around the bowl until it escapes through the elevated tower hole.
- On its way through, it lifts the black sand so that it falls down through the tower hole. As gold is much heavier than black sand, it will stay at the bottom.
- To ensure that no gold escapes, a couple of rifles have been added around the tower to capture any gold particles that still manage to lift themselves up towards the tower hole.
When running the blue bowl, you especially need to keep three things in mind:
1. Classify the material first!
The gold bowl works best if all particles are fairly similar sized. The reason is that a mix of different sized particles makes it hard to find a flow speed which ensures that only black sand particles are disposed of. The higher flow speed trequired to get rid of the bigger black sand particles might simply be enough to make you lose the really tiny gold.
We recommend that you classify your material into something like 30, 50, and 100 mesh, and run the blue bowl separately for each. (or something along those lines)
2. Adjust the speed of the water flow to fit your material
The speed of the water flow should be just enough so that black sand can escape the tower hole. This step requires some fine adjustments and experience. However, you come a long way just watching the particles that travel up the tower.
Quite logically, the coarser the gold, the more aggressive you can be with the speed of the water flow.
3. Let it do its thing!
The blue bowl works best when it’s given a long time to concentrate the gold. Don’t be in a rush, as you will risk losing some of the gold in the process. Once you have adjusted the water flow properly, let it go for an hour or two until the gold looks really clean!
4. Keep It Leveled
It’s really important to keep the blue bowl perfectly leveled to allow the water to flow evenly. Remember, as you are dealing with really fine gold, you have quite small margins.
To round off this section, we present you with a great video showing how to operate a blue bowl.
3. Gold Cube
Recommended for: Serious prospectors
The gold cube is an extremely capable machine that can capture very tiny gold, while at the same time being able to handle big quantities of material with very small losses.
With that said, it’s not a machine you would use to process smaller quantities of material from manual gold panning or smaller sluice boxes. For smaller quantities, regular gold panning or the aforementioned gold bowl really are better options.
However, if you have bucket loads of black sand to process, the gold cube really is an excellent choice. It will get the job done quickly with very little to no losses.
How Does a Gold Cube Separate gold from black sand?
In short, the gold cube is made up of three or four stacks, depending on the configuration.
Water runs through the first stack, which is equipped with a water diffuser that spreads the water evenly across a slick plate.
The water then runs into the second stack, which is equipped with a G-force separator and a vortex matt, where the fine gold will get stuck.
The G force separator simply is a small turning channel, which the slurry falls into.
In the process, the gold is pushed towards the bottom while the lighter material speeds through the channel and escapes at high speed. Being much heavier, the gold just manages to get out of the separator and fall directly into the following vortex matting, where it gets trapped.
This above process is then repeated for the remaining number of stacks.
Quick Tip: Always make sure that the mats are completely soaked in water, and that the last section leading to the g-force separator doesn’t have any bubbles. Otherwise, you risk having some of the gold escape the device.
4. Miller Table
Recommended for:
The miller table is a gold separation device that consists of a flat sheet of matting inside a sluice, with water flowing over it. The black sand concentrate is dispersed gently at the start of the matting. The lighter black sand is then pushed down the matting, while the heavier gold stays where it is and can be collected.
It’s worth noting that this gold separation technique generally works better with flat gold pieces, than with round pieces. The latter tend to simply roll off the table, whereas the flat pieces lay down flat with the flow of the water keeping it in place.
As always, it’s recommended that you are careful when adjusting the water flow so that it doesn’t remove too much of the fine gold. As a rule of thumb, the flow of water should be strong enough to carry the black sand particles away, but too weak to have the gold particles go with them.
Quick Tip: Just as the blue bowl, the miller table benefits from running with less aggressive water flow, but for a longer period of time.
5. Magnets
If you have concentrated your material down to just black sand and gold, a magnet could be of great help. Since black sand mainly consists of magnetite and hematite, which both are magnetic, a magnet can be used to attract the black sand and leave the gold behind.
Now, just picking your old horseshoe magnet won’t do. You need a very strong magnet, such as those specifically geared towards gold miners. These are strong enough to remove a bigger portion of the material, and will make your life easier.
A few tips:
- You either completely soak the black sand in water, or make sure that it’s completely dry. Otherwise, you risk pulling a lot of the gold with the black sand.
- If you just grab the black sand with the magnet and dispose of it, you will be losing a lot of gold. Instead, drop the material into a second container, and pick it up again with the magnet. Do the same, this time from the second container to a third one, to free any remaining specks of gold. This process is shown by the eminent prospector Dan Hurd in the video below:
Although this can be a great method, I am personally more inclined towards using some of the other methods already discussed in this article. There is a significant risk of losing a lot of gold if you are not careful. This alone might not make a magnet the ideal solution for somebody who is just starting out.
More Extreme Methods
These methods are not some that you would engage in as a recreational prospector most of the time. Usually, they are employed to catch the tiny remaining amounts of gold in larger amounts of black sand, where the more traditional methods simply won’t do. As such, these methods are usually employed as a second step if any of the methods covered earlier in the article still leave some gold to be extracted.
Now, to know if it is worth proceeding with more extreme methods, you should take a black sand sample and see if it contains some gold or not. This is usually done with a microscope or a loupe.
With that said, here are two great techniques!
1. Soaking Your Black Sand in Hot Water and Soap
If you discover that the gold is attached to the black sand, you want to find a way to break that bond. Fortunately, there is an easy way! You simply hot bathe the black sand! In most cases, this will be enough to break the bond and release most of the gold.
Here are the steps:
- Heat some water
- Add some soap to it.
- Hot bath the black sand, and give it a nice stir.
2. Crushing the Black Sand
Sometimes one black sand particle will merge with several other grains of black sand, and capture some gold in the process. If this has happened to enough extent, you might decide to crush it to extract the gold.
Now, it’s recommended that you try the hot bathing method before resorting to this somewhat more extreme solution. There is a good chance that it’s enough to release most or all of the gold.
However, if there really is a lot of gold caught in the material, then crushing the black sand might be a good idea. However, many times, there is so little gold left that it isn’t worth the effort.
One common method of crushing the black sand is to pour it into a cement mixer, into which some ball bearings are added to crush the material.
Another option that doesn’t need as much equipment is to heat up the black sand and then pour it into cold water. The idea is that the rapid change in temperature will be enough to release the gold.
Never heat up your black sand indoors. If your area contains mercury, it will vaporize at high temperatures and should not be inhaled.
If you want to know more about the methods discussed here, I really recommend you have a listen to this episode of Kevin Hoagland’s excellent podcast “On the Gold”.
Confused? Here Is Our Advice!
We’ll keep it short:
Go for normal gold panning and add a blue bowl to the mix if you feel you need it.
That’s really all!
Final Words
There are many methods available for separating gold from black sand, and this article has only delved into some of the most common ones.
However, there is no need to learn them all. Just becoming good at panning, perhaps combined with a blue bowl, will take you really far as a hobby prospector. Then, if you get larger quantities of material to work through, you might want to have a look at the gold cube or similar devices!
Happy panning!