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| Mercury and Black Sands |
| Updated 11/7/2006 |
(Re-Printed from TOM ASHWORTH)
There have been many questions about how to get gold out of black sand. I thought I
would post a method that I use on cleaning up on my 6" Dredge. I clean up the top of my
sluice box everyday and the rest of the sluice box when it is needed. One problem I see
with a lot of new miners is they clean up too often and this takes away from the time the
could be dredging and finding more gold. If you have the sluice on your dredge set up so
that the gravel is not getting too full between the rifles and not running so fast that it
sweeps the rifles, then once a day clean up is all you should need on most store bought
dredges. The perfect set up for the sluice is so you have about one quarter inch of carpet
showing between the gravel of the middle riffle of the sluice and the one below it. Now
dredge all day.
There have been many questions about how to get gold out of black sand. I thought I
would post a method that I use on cleaning up on my 6" Dredge. I clean up the top of my
sluice box everyday and the rest of the sluice box when it is needed. One problem I see
with a lot of new miners is they clean up too often and this takes away from the time the
could be dredging and finding more gold. If you have the sluice on your dredge set up so
that the gravel is not getting too full between the rifles and not running so fast that it
sweeps the rifles, then once a day clean up is all you should need on most store bought
dredges. The perfect set up for the sluice is so you have about one quarter inch of carpet
showing between the gravel of the middle riffle of the sluice and the one below it. Now
dredge all day.
After dredging all day I empty my dredge into a large wash tub. I then screen those concentrates using a 20 mesh
screen into a 5 gallon bucket. I then pan the concentrates that did not go through the 20 mesh screen while down
at the river (looking for nuggets of course). Any gold found in the concentrates that were to large to fit through the
20 mesh screen, I put in a vial. I then put a shovel sluice (a Keene or Le Trap sluice works well) inside the dredge
sluice so that the shovel sluice is close to the header box or jet flare (Note: This only works on 5" and larger
dredges). I use a modified Keene A-52 sluice. It has some NoTrax matting glued in the top to catch fine gold. I then
start the engine on the dredge at idle so the water runs down the shovel sluice. I adjust the engine so that the
water flow is swift enough to wash out light sand and still save all of the black sand and gold. The out put of the
shovel sluice goes back into the dredge sluice and there are still several riffles in the dredge sluice that will catch
any flour gold that happens to escape (this will remain until the next time I dredge). I then scoop the concentrates
that I screened into the shovel sluice. When all concentrates are ran. I then empty the shovel sluice into a 5 gallon
bucket. I then have <20 mesh extreme concentrate.
screen into a 5 gallon bucket. I then pan the concentrates that did not go through the 20 mesh screen while down
at the river (looking for nuggets of course). Any gold found in the concentrates that were to large to fit through the
20 mesh screen, I put in a vial. I then put a shovel sluice (a Keene or Le Trap sluice works well) inside the dredge
sluice so that the shovel sluice is close to the header box or jet flare (Note: This only works on 5" and larger
dredges). I use a modified Keene A-52 sluice. It has some NoTrax matting glued in the top to catch fine gold. I then
start the engine on the dredge at idle so the water runs down the shovel sluice. I adjust the engine so that the
water flow is swift enough to wash out light sand and still save all of the black sand and gold. The out put of the
shovel sluice goes back into the dredge sluice and there are still several riffles in the dredge sluice that will catch
any flour gold that happens to escape (this will remain until the next time I dredge). I then scoop the concentrates
that I screened into the shovel sluice. When all concentrates are ran. I then empty the shovel sluice into a 5 gallon
bucket. I then have <20 mesh extreme concentrate.
To do the final cleanup I use a panning wheel and a micro sluice. You can also pan down to get to the last of the
impurities. These impurities usually consist of a small amount of black sand, a few iron rocks, and pieces of lead.
There are many ways to go about doing this final cleanup. Personally, in general cleanup I like to stay away from the use
of mercury, as there is a faster way without it. I also like to stay away from the use of nitric acid because its usually not
needed either. There are times when the use of mercury and nitric acid can help speed thing up. Usually though, I can do
the final cleanup without them.
impurities. These impurities usually consist of a small amount of black sand, a few iron rocks, and pieces of lead.
There are many ways to go about doing this final cleanup. Personally, in general cleanup I like to stay away from the use
of mercury, as there is a faster way without it. I also like to stay away from the use of nitric acid because its usually not
needed either. There are times when the use of mercury and nitric acid can help speed thing up. Usually though, I can do
the final cleanup without them.
Here's one quick procedure to do the final cleanup;
(1) Dry out the gold by pouring it into a metal pan and heating it over a stove outside. Don't get it so hot that any pieces
of lead which are still with the gold will melt. Heat it up just hot enough to dry it out. It is a good idea to stay upwind
anytime you put gold in a pan and heat it up. Mercury attaches itself to gold in different amounts. Often it's there but you
can't see it. When heating the gold to certain temperature, the mercury vaporizes off. These vapors are very dangerous.
So it is good practice to heat your gold outside and downwind of you, even when heating it up just enough to dry it out.
Also, the pan you use for heating up gold during cleanup should be used only to cleanup, not for cooking. I use a
portable hot plate for this.
(1) Dry out the gold by pouring it into a metal pan and heating it over a stove outside. Don't get it so hot that any pieces
of lead which are still with the gold will melt. Heat it up just hot enough to dry it out. It is a good idea to stay upwind
anytime you put gold in a pan and heat it up. Mercury attaches itself to gold in different amounts. Often it's there but you
can't see it. When heating the gold to certain temperature, the mercury vaporizes off. These vapors are very dangerous.
So it is good practice to heat your gold outside and downwind of you, even when heating it up just enough to dry it out.
Also, the pan you use for heating up gold during cleanup should be used only to cleanup, not for cooking. I use a
portable hot plate for this.
(2) Once the gold is dry, bring it inside, out of the wind, and pour it onto a piece of clean paper. You can now pick
out the larger impurities from the gold with tweezers.
(3) Now a magnet can be used to extract most of the remaining black sands for you gold. I use a super magnet,
but I used to use the Keene Gold Magnet. The Super Magnet is just larger.
(4) By lightly blowing over the gold, you can finish extracting the rest of the impurities. If you can locate a very fine
screen you can use it to separate the smaller pieces of gold and impurities from the larger ones just after drying it
out. This speeds the process up a bit.
(5) Put your gold back in the metal pan, take it outside and heat it up, hotter this time, in order to vaporize any
further mercury for the gold. This will bring your gold back to the basic deep rich beauty which we love.
(6) Now you can put it in a bottle. If you want to sell it keep it dry, but if it is for show put water in the bottle to keep
it beautiful. The water will also prevent the glass vial from breaking due to the weight of the gold.
out the larger impurities from the gold with tweezers.
(3) Now a magnet can be used to extract most of the remaining black sands for you gold. I use a super magnet,
but I used to use the Keene Gold Magnet. The Super Magnet is just larger.
(4) By lightly blowing over the gold, you can finish extracting the rest of the impurities. If you can locate a very fine
screen you can use it to separate the smaller pieces of gold and impurities from the larger ones just after drying it
out. This speeds the process up a bit.
(5) Put your gold back in the metal pan, take it outside and heat it up, hotter this time, in order to vaporize any
further mercury for the gold. This will bring your gold back to the basic deep rich beauty which we love.
(6) Now you can put it in a bottle. If you want to sell it keep it dry, but if it is for show put water in the bottle to keep
it beautiful. The water will also prevent the glass vial from breaking due to the weight of the gold.