Fine Gold Recovery From Black Sand Concentrates
by Greg Mulac
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 off 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 you 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 I ended up using . The set up is basically a 2 foot house rain gutter with black miner's mat and some aluminum mesh over the mat. To see what it looks like, just go to eBay and search Mini Sluice For Concentrates. Make sure to click the search titles and description box.
The water is powered by a small 12 volt bilge pump that sits in the recovery tub. There are also hose feed models, but I prefer the self contained units.
So we will now assume you have taken the first steps and screened out all the rocks and any big things that will deter you from getting to the fine gold. There are many commercial products out there for classifying as well as using basic household colanders and screens to accomplish this. I prefer and recommend the commercial ones designed to fit into the gold pans and into each other.
Next we will use a gold magnet to start the black sand removal from the fine concentrates. Since you are starting with dry concentrates this is relativity easy -- pass the gold magnet over the concentrates to separate the black sand from the gold bearing sands. I take the black sand and put it into a rock tumbler with some different size white quartz rocks that I know every one has laying 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. I have a smaller gold magnet for this purpose, a gold magnet lets you engage and release the magnet and put the black sand where ever you want it -- not where it wants to go. You never want to use a regular magnet with out putting some type of easily removable cover between the sand and the magnet; you will ruin the magnet because you will never 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 process .
This process 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. My advice is to find some one who does this and if you like them give them the black sand when you are done - if not sell it to them.
I hope this information helps you to continue enjoying and profiting from your gold hunting adventures. And I hope every shovel of dirt you turn over or every dredge hole you dig is full of gold!
Greg Mulac traveled the globe 25 years pursuing Gold Prospecting / Treasure Hunting passions. Today, retired from an IT Career, he thrives in SEO and Internet Marketing ventures.