For every gold prospector out there that has been doing it for more than 3 hours, you have a ready supply of concentrates that are full of black sand. Your plan is to take it home because you know there is more fine gold in there than you were able to get out of the pan and into a bottle while you were at your favorite spot.
Well, after doing this a few times and when it gets to be buckets of gold laden concentrates full of black sand, you need to do something to make the buckets go away and the fine gold find its way into a nice bottle! You also know you have a problem and need to do something when you have to sweep up the basement floor and run the dirt back through your dredge before you can throw it out.
There are many ways to deal with this and lots of products out there, from the spiral wheels to the GPAA marketed mini sluices, which are real similar to what most people use.
One common setup is basically a 2-foot house rain gutter with a black miner's mat and some aluminum mesh over the mat. To see what it looks like, a simple eBay search on "Mini Sluice For Concentrates" will give you ample photos.
A small 12-volt bilge pump that sits in the recovery tub powers the water. There are also hose feed models, but most people prefer the self-contained units.
Assuming you have taken the first steps and screened out all the rocks and any big matter that will deter you from getting to the fine gold, you are ready to proceed. There are many commercial products out there for classifying as well as using basic household colanders and screens to accomplish this.
Next, use a gold magnet to start the black sand removal from the fine concentrates. Since you are starting with dry concentrates, this is relatively easy. Simply pass the gold magnet over the concentrates to separate the black sand from the gold bearing sands. The black sand can be put into a rock tumbler with some different size white quartz rocks that most people with this hobby have lying around. After running the tumbler for a few days, this black sand is ready to go through the mini sluice for the first time.
While the dry black sand is running in the tumbler, we will now run the sandy concentrates that were left through the mini sluice and remove more black sand. You can buy a smaller gold magnet for this purpose as it allows you to engage and release the magnet and put the black sand wherever you want - not where it wants to go. You never want to use a regular magnet without putting some type of easily removable cover between the sand and the magnet; you will ruin the magnet, because you will never be able to get all the sand off the magnet.
With a steady flow of water running through the mini sluice, feed the concentrates or tumbled black sand into the sluice. Add a small amount (like a tablespoon at a time) and let the water and gravity do their job. While this process is ongoing, you should be using your smaller magnet to remove the black sand from the sluice and place it in a gold pan or other non-magnetic container to dry. Then repeat the process.
This entire procedure will continue until you stop getting gold you can recover. There are ways to remove the ultra fine micro gold that you cannot see, but this involves using chemicals and other processes. The best advice is to find someone who does this and you can either give it to him or her or sell it.
Following these easy steps will enable you to continue enjoying and profiting from your gold hunting adventures!
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