Thursday, March 12, 2009

2 Fine Gold Recovery Systems for Black Sand Concentrates

(Auriferous black sand highly magnified.)


Although I've mentioned fine gold recovery from black sand concentrates in various posts here in "Bedrock Dreams" in passing, but I've not gone into any depth on the subject. Now it's time took take a more detailed look at this important aspect of gold recovery and perhaps shed some additional light on the subject. (NOTE: When I speak of black sand concentrates in this post I am assuming all larger pieces of gold such as nuggets, "pickers," and bigger flakes have already been removed.)

What are Black Sand Concentrates?

Black sand concentrates are primarily a combination of small-to-medium grains (although micron-sized grains are common as well) of primary iron group minerals such as:

Magnetite (Fe3o4)

Hematite (Fe3o3)

and precious metals in the form of minute or micron grains of:

Gold (Au)

Silver (Ag)

Platinum (Pt)

Although their specific gravities are only about 1/3 to 1/2 that of gold, black sand concentrates are still heavy enough to remain in your gold pan or sluice box after other much larger materials (rocks, larger gravel pieces, etc.) have been washed away.
(Micro sluice set up from Metal Detecting World.)

There are a number of efficient methods used for recovering extremely fine or micron-sized gold particles from black sand concentrates, but trying to isolate or pick them out by hand is not one of these. Although micro-sluices do a pretty good job of recovering fine gold from black sand concentrates, I recommend 2 pieces of mining gear that I think work best in this regard:

1. Spiral Gold Wheel

These are very efficient fine and micron gold recovery systems that, for the most part, are fairly inexpensive. A well constructed and properly set up spiral gold wheel can process up to 50 pounds of black sand concentrates per hour and still produce perfectly clean gold on the output end.

They can be purchased directly from a number of manufacturers or from prospecting/mining supply stores. I recommend you acquire a green spiral wheel as opposed to black, blue, purple or any other colors out there. Why? Dark green shows gold better. How do I know this? Thirty years mining experience has proven it to me. But if you are a cynic and need first-hand proof, try a comparison of colors yourself and you'll see what I'm talking about here.

Gold Pans
Gold Concentrators

2. "Blue Bowl" Concentrator

"Blue Bowl" concentrators are arguably the best fine gold recovery systems out there. They are simple, easy to use, and extremely efficient when set up and operating properly. Most experienced miners agree that "Blue Bowls" work best when the concentrates have already been "classified" using a 20-30 mesh screen first.

"Blue Bowls" get their name from their color (duh, right?). Again, I don't think blue is an optimum color background for making gold highly visible, but it works. If, by some strange twist of fate, you come across a dark green bowl, grab it! Again, "Blue Bowl" concentrators can be purchased ready made from any number of suppliers or, if you are good at do-it-yourself projects, there are actually a few kits out there.

The Exception Rather Than the Rule

If you are an experienced miner you already know that fine and micron-sized gold particles represent a good part of the take from any gold recovery operation. Those of you who are novices will learn this fact quite quickly, especially after you realize that coarse gold such as nuggets and "pickers" is the exception rather than the rule in most instances.


That's why a spiral gold wheel or a "Blue Bowl" concentrator are handy items to have around. So save those black sand concentrates. Myself? I like to process them during those "cabin-fever" winter months. Keeps me out of trouble and allows me the opportunity to "mine" year round.

Be safe out there.

If you liked this post, you may want to read: "One Reader's Unique Perspective on the Rahall Mining Bill"

(c) J.R. 2009

Questions? E-mail me at jr872vt90@yahoo.com

12 comments:

  1. good to know, been tossing my black sands as no "seeable" gold! aaagh! have to get a blue bowl and keep them concentrates. Great info here thanks

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  2. Thanks for the comment. Let me know how that Blue Bowl works out, OK?! J.R.

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  3. Thx this is good info for new to prospecting

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  4. It is very important to classify your cons so they are nearly the same size. To knowledgeable people it can pay immensely to use mercury on fine gold but you have to know what you are doing so it doesn't become dangerous. Micro sluicing is a very valuable tool as is a simple Miller table. We use all of these methods on the beaches of Nome which has 99% fine gold. Smokin' Joe

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  5. Thanks for the great comments and helpful info Smokin' Joe. I appreciate it and I 'm sure the readers will too. Be safe up there in Nome! J.R.

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  6. Right on, Thanks for the info on the blue bowl i have been crushing quartz picking out what i can and saving the rest. i have a ton of material that contains flour and micro gold now i can finally run it and get it out of the garage.

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  7. That's the way to do it my friend! Good job. Thanks for commenting. J.R.

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  8. has anyone ever used the "roto pan"? I have been thinking I'd build something based on the same concept.

    -Bo

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  9. I haven't used the "Roto" myself Bo. Anyone out there with experience using it? Please respond to Bo's query. Thanks. J.R.

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  10. Finely!!!!!!!! some real good useful information!!!!thank you J.R all I have here in Nova Scotia is very very fine gold can't see it with out at least a 50 power lense. will be getting me one of them blue bowls..thanks again.


    mack

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  11. You're most welcome Mack...the Blue Bowl works well for us small guys! Best to you and yours, J.R.

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