# Extracting Possible Metals from 1/2 Gal. of High-Density Mud



## Photobacterium (Dec 1, 2013)

I have access to part of an abandoned placer mining operation.

After much work, I used a sluice to process about 500 pounds of mud from the site of a winter stream that is about 100 yards uphill from the original placer operation.

The density of the mud I was processing was about 11 pounds per gallon. I learned this well because I got to carry all of the raw possible placer mud out of there in 5 gallon buckets. 3 gallons of it weighed 31 to 37 pounds, 1 pound for the bucket.

So by processing the 500 pounds, I got it concentrated down to a much higher density mud with a density of 15 pounds per half gallon - 30 pounds per gallon, up from about 11 pounds per gallon.

That is higher-density mud. Water would weigh about 7 1/2 or 8 pounds per gallon.

Now I want to concentrate the mud even more - and extract whatever metals are in there.

I have access to aqua regia at a reasonable cost.

One of my "mining coaches" is a local miner who used all gravimetric tools in a dredge type operation on Oregon rivers. He is very skilled and finding 'streaks' of color (i.e. Gold) and dredging & sluicing to get a concentrate. He uses a Blue Bowl when he gets to this part of ther operation.

I say "used" (as in past tense) because he is confounded by new Oregon mining laws that make his life much more difficult.

One of my other coaches, since departed, was enthusiastic about "The Cube", vibrating tables, and the Spiral Wheel, for separating fines.

If there is any gold in this mud, it is flour gold. Or I need better glasses.

I am encouraged by the density reading, but am also facing an approaching winter storm, so that I will most likely be choosing indoor activities for the rest of December. i.e. whatever I get out of the sluice in the next day or 2 is, "That's it for a while."


Is Aqua Regia a good tool for this stage of an exploratory mining project - performed by a mining newbie ?

If I were to do that, I would be going in without knowing how much Gold is in the higher density mud. I would simply heat the combination of mud + Aqua Regia, and then filter it. Then use SMB to attempt to precipitate any metal in the filtrate. The Aqua Regia with a ratio of about 1:3.5 (HCl to Nitric, if I remember), and HCl at 31% (using Muriatic, then diluting 50% Nitric to get the approximate ratio).



The miner who uses the blue bowl doesn't have access to Aqua Regia. I'll be showing him the sample tomorrow or Tuesday.

But I thought I'd ask you guys. Thanks for any technical directions !


----------



## Westerngs (Dec 1, 2013)

Sight unseen, try on a very small sample first, say a couple of grams of mud. Then check the AR using stannous chloride. This will tell you if you have any PGM's in solution.


----------



## torscot (Dec 1, 2013)

Tying to do that much material with AR will consume so much acid you'll have to buy it by the barrel. Any carbonate minerals (calcite), and copper, silver will consume and pollute your acid. Time and $ waster. Do the test that westerngs suggests,(Qualitative test) several times from several of your pails. If it shows gold, then take some samples to your old timer with the spiral wheel and get him to run it. Remember to weigh it dry (1kilo) and have him run it through the wheel, Weight what you recover (Quantitative test). work it out over the balance of your marterial. if it's worth it then spend some of your own money and buy your own spiral wheel. They're $300 on ebay. I own one, and I use it on silver, they are magic to watch work on gold. Then spend your winter recovering your gold. The other ways to recover are leaching, and I have no knowledge of that.

Good luck. 
Rob


----------



## butcher (Dec 1, 2013)

This is placer gold, pan it or process it with another gravity means of separation.
No way would I try to extract gold from that bucket of mud with aqua regia.


----------



## GOLDbuyerCA (Dec 1, 2013)

I am for saying, NO ACID also, i have done 50 lbs, of mud like stuff, " from sweeps at a gold and diamond place " alloy gold, 14k average, .. i used a blue bowl, and a gravity table, multi time processing , and keeping all the mud. but the gold load, is way higher, than in the wild old placer sites. imo., i got 2 and a half ounces per fifty lbs, and a 6 inch quarter width tube of diamonds, aprox 100 up to half carat sizes. from the mud, the Diamond merchant was so happy getting the small diamonds back, from 12 to 75 bucks trade. that he netted me all the gold. days of 300 an ounce. it was hard work, very careful washing and shaking, flow can not be to high, using a gravity trap method, and patience is required, and you have to net something for your worth. i will guess you may have 2 to 5 grams, recoverable in the whole lot, placer miners don't spill much good luck with it,


----------



## Harold_V (Dec 2, 2013)

Photobacterium said:


> But I thought I'd ask you guys. Thanks for any technical directions !


Can you say "fire assay"?

I do not mean to sound rude, but if you knew what I do about a gentleman, his friend, and his father-in-law, who spent three months working a claim, and witnessing his father-in-law die from a heart attack because they were too remote to get the badly needed medical attention, you might understand my posture in this matter. 

The gold recovered by these three men amounted to just over five ounces. A pittance as compared to the three months they spent, based on the idea that "they could see gold". Had they paid for an assay, they'd have known they were spinning their wheels. 

If you think you have something of value, pay for an assay. If you just want to pretend you have something, and don't want your bubble burst, just continue the course. An assay will tell you if this project warrants any further attention. It may not, and most likely does not. 

Just sayin'!

Harold (the world's greatest skeptic)


----------



## butcher (Dec 2, 2013)

Placer mining can be different than mining ore, creeks rivers or ancient rivers, can have pockets of gold, or no gold, or just fine gold mixed with the heavier black sands.
Gold washing down rivers is trapped or settles in some spots as it flows, or rolls down river toward the ocean. 

If this is a 20 acre placer mining claim you plan to spend time working it, then getting various samples of of the whole claim you plan to work, for assay would be wise.

This can be done by panning your test samples from the bedrock of several different areas of the claim.

Sending a sample of that 5 gallon bucket in for an assay would not tell you much, you may not have any gold in the spot you dug that mud, or it could have been the only pocket of gold on that whole claim of 20 acres .

Edit to add info to this post instead of starting another.

https://www.google.com/#q=placer+gold+assay+screened+40+5gal+buckets%2Fyard+assay+cubic+yards+x+pounds%2Fcubic+yard+divided+by+2000

Knowing how many cubic yards or tons of rock and gravel, and how deep to bedrock you will have to dig and move to get a gram of can help keep you from working a useless claim.

Fire assays of the concentrate is likely to show up the minerals that are also locked up in the concentrate sample you sent in, not just the free gold you would be able to recover, unless you smelted the concentrate you mined to recover those also.

Your sampling and assay of the placer material should show you how much of that river bed rock gravel and sand you will have to move and work to get that gram of gold.
but with gold in deposits rich, poor, or none, and just in certain pockets or areas of the claim, even after you dig and run enough material to get several areas of the claim tested for value per cubic yard or ton, you only have a small clue as to what the whole claim holds, your still gambling your samples did not come from the richest part of the mine, if the sample came from only a rich spot you could be mining yourself to the poor house, after moving tons of material mining to find there were no more rich spots in that 20acres of creek.


Even with good sampling mining a placer claim is a gamble, and taking good samples just gives you a small clue as to if the gamble is worth it, but that is a lot better than not having any clue at all.


----------



## Photobacterium (Dec 5, 2013)

I made Stannous Chloride following GoldnScrap's directions @ -
http://www.goldnscrap.com/index.php/gold/63-stannous-chloride-test-for-gold-platinum-and-palladium-presence

I used 4 grams of the 95% Tin- 5% Antimony Solder in 60 cc of 31% HCl. Most of the metal dissolved. I filtered it. I checked Antinomy in HCl (re. if it dissolves, there seems to be a consensus that it doesn't). Presumably the small amount of metal I am filtering (much less by volume than the original 4 grams of solder) is Antimony.

To test the (hopefully) detector solution I dissolved 3 cut-off gold plated connector strips from PCI circuit boards in 2 fluid ounces Aqua Regia.

Separately, I tested the Nitric in the AR using a piece of copper, it certainly dissolved it.

I have been using coffee filters to do a test, on a white paper background. However, I am whetting the filter that gets the 'pregnant' AR by dipping the filter & then putting it on the background. Then I add a drop using the second coffee filter. ( I have a lot of coffee filters.) BUT NO PURPLE.


goldnscrap says to just use one drop of pregnant solution & one drop of Stannous.

I would like to make the Stannous test works before I do anything more with the 1 gallon of "Heavy Mud".

So I used a clean plastic fork and dropped one drop of 'pregnant' AR and one drop of Stannous Chloride on a piece of white paper, temperature @ about 32 degrees F. It is definitely not purple. It is more tan/yellow. It definitely has dissolved Gold, not a lot though. So now I question the Stannous Chloride I made.

There is a guy named "Loudwolf" that sells Stannous Chloride detector solution on eBay.

http://www.ebay.com/itm/Stannous-Chloride-Gold-Platinum-Palladium-test-soln-1oz-2-PACK-2-x-1-oz-/390697651851?pt=LH_DefaultDomain_0&hash=item5af7650e8b

I am willing to pay for known good Stannous from a third party.

The Tin-Antimony 95/5 solder that I used is made by "Oatey". The Muriatic/ HCl that I used is Transchem.


*Question #1 - why isn't my Stannous test working ? Not enough gold in the test solution, too cold, or something else ?*


As far as a fire assay, that is what got me started in the first place. I did a sort of fire assay (using lead powder instead of the oxide) and that did yield a small sphere of metal (that wasn't lead and was not absorbed by the cupel).

I welcome hearing about a lab or knowledgeable shop in Southern Oregon to test the "Heavy Mud" by doing a fire assay. One local miner told me about a shop that does it unofficially (i.e. they don't advertise it), I just sent them an email but that's as far as I got.
*
Question #2 - Can someone recommend a lab near Southern Oregon for the fire assay ?*


I can relate to what Harold said about the 3 men & 5 ounces. It reminds me of the book "Fire & Ice", about Revlon founder Charles Revson. During an interview, someone asked him about the cosmetics business. He said, "Well, what I'm really selling is Hope".


----------



## butcher (Dec 5, 2013)

Your stannous chloride may work? Did you de-NOx the gold solution.
Hoke's book will help, read about making yourself a standard gold solution to test your stannous chloride with.

Sandy Oregon Action Mining sells supplies and has lab services.
http://www.actionmining.com/
http://www.actionmining.com/Catalog.pdf


----------



## butcher (Dec 5, 2013)

Unless you separated the gold from the "mud" or heavy sands, using aqua regia will put mostly Iron in solution, if gold is attacked by the acid it will be cemented back out of solution back with the remaining sands by other base metals in the mud mix.
this is not to say that if you tested a sample that you would not see some gold in solution with the iron chlorides, the stannous chloride test is a very sensitive for gold, even a very tiny bit of gold in solution will give a positive reaction of purple, so you could get a positive reaction to a test of this leach but have very little actual gold in solution, with most all of the gold undissolved in the sands as you waste your acids dissolving iron.

About all this kind of test would be able to tell you is that there is at least a minute amount of gold in the mud, still basically a waste of time in my opinion.


----------



## rickbb (Dec 5, 2013)

Using 2 cut off fingers from PCI cards would yield a very, very small amount of gold. Doing it in 2 fluid ozs. of AR would make the concentration of gold in solution very low and is why your stannous test shows only light tan. Stannous will go darker with more gold dissolved in solution. 

I'd say your stannous is fine. You can put more of the solder in, in fact many people put in more than the HCL will dissolve. Kind of like automatic replenishing of tin in solution.


----------



## butcher (Dec 5, 2013)

If there is no violet (or black for heavy concentration of the violet color) in the stain I would say no gold in a tan spot, or yellow stain, stannous chloride is an extremely sensitive test for gold in solution, it can detect even a few PPM in dilute solutions, I see no reason you should not see a violet reaction as long as the stannous chloride was able to reduce the gold in solution to a metal colloid in solution. oxidizer or free nitric acid can redissolve the gold, or basically not letting the stannous chloride reduce the gold to metal.

(tan could just be copper being reduced by the stannous chloride).

For this test to work we must reduce the gold ions back to metal,(give gold ions electrons), with oxidizers in solution it can overcome the reducing agent (our stannous chloride).

Spend some time in Hoke's book and doing the getting aquianted experiments.


----------



## FrugalRefiner (Dec 5, 2013)

Photobacterium said:


> To test the (hopefully) detector solution I dissolved 3 cut-off gold plated connector strips from PCI circuit boards in 2 fluid ounces Aqua Regia.


I could be wrong, but I would say you used WAY to much acid when you created your gold standard solution. You should use only as much acid as is needed to dissolve whatever amount of gold you choose to use. Once the gold is dissolved, you can dilute it to whatever concentration you desire. But if you have an excess of nitric acid in your standard solution (which you do), when you add your stannous solution to the gold solution, any gold that is reduced (which would show the purple to black color) is immediately redissolved.

Butcher asked earlier if you had deNOxed your gold solution and is right on point with his last post.



butcher said:


> oxidizer or free nitric acid can redissolve the gold, or basically not letting the stannous chloride reduce the gold to metal.
> 
> (tan could just be copper being reduced by the stannous chloride).
> 
> For this test to work we must reduce the gold ions back to metal,(give gold ions electrons), with oxidizers in solution it can overcome the reducing agent (our stannous chloride).


Dave


----------



## butcher (Dec 5, 2013)

Hokes book will help to solve this problem.
Testing and identification of metals in solution is so important, this should be one of the first skills you work on, if you cannot see the values, or know how to test for them, you have no idea where they are, and without knowing where they are you can easily lose them by working blind folded.


----------



## Photobacterium (Dec 6, 2013)

butcher said:


> Your stannous chloride may work? Did you de-NOx the gold solution.
> Hoke's book will help, read about making yourself a standard gold solution to test your stannous chloride with.
> 
> Sandy Oregon Action Mining sells supplies and has lab services.
> ...



FANTASTIC !

Thank you all for the replies & PM's.

I was going to send one sample to Action. I'm drying it now.

I am curious if the de-Noxx-ization is related to the NO3 in HNO3 interfering with the action of the Stannous Chloride, or if it is the H3O+ in general (like you would find in LazerSteve's HCl+ NaClO - sodium hypochlorite/Clorox - recipe).

The log of the molarity of the H3O+ yields the pH of the solution.


Put another way - if I dissolve some gold fingers in the HCl-NaClO solution, would the Stannous Chloride work straightaway ?

I am re-reading Hoke and dissolving some Copper (no Zinc) in the semi-pregnant Aqua Regia before trying the Stannous again.

Then I thought I would experiment with the use of Stannous in HCl-NaClO. But I'm interested in hearing your experiences !


----------



## butcher (Dec 6, 2013)

For a metal to dissolve, we take electrons from the atom of that metal, leaving Ions of that metal in solution as Cation's.
Oxidation = loss of electron.

To reduce this metal Cation, back to elemental metal, it needs that missing electron to complete the shell of the atom.
Reduction = gain of electron

In a chemical reaction if something is oxidized something else has to be reduced.

As gold dissolves (oxidization) the oxidizer and acids are reduced, nitric reduces to gases of NOx gas; the HCl is reduced to chlorides

When dissolving gold we cannot oxidize the gold (take electron from its atom) with HCl alone, HCl is not an oxidizing acid strong enough to dissolve the gold.

Nitric acid is a strong oxidizing acid capable of oxidizing gold (take an electron away from the gold atom). 
But in a nitric acid solution alone, the gold will not dissolve the electron even when pulled from the gold atom wants to go right back, so basically the reaction stops and no gold goes into the solution.

When we mix these two acids we produce gases in solution that can easily attack the noble metal gold and help to dissolve gold into solution.

The nitric oxidizes the gold (taking the electron away from the gold atom), forming a Cation of gold, the gold Cation attaches with three Anions of chloride (from the reduced HCl) to form AuCl3 in solution, and the process proceeds as long as there is acid or oxidizing agents to continue the process, once we run out of these oxidizing agents we can put no more gold in solution in these conditions.

If we use up one or the other of these, the nitric or the HCl needed in solution to dissolve all of the gold metal we have.
When either one of these are limited or not available in solution the chemical reaction will no longer dissolve more gold.

We need both HCl and HNO3, if we run out of either one in the process it will come to a halt, excess HCl acid in our process does no harm, but excess HNO3 can become a problem later (in the process) when we go to reduce our gold back to metal, this is why we suggest limiting the amount of nitric acid used (oxidizer), this oxidizing acid will need removed later when we go to reduce our gold (precipitate it, or test it with stannous). If we do not use this oxidizer up or remove it (through de-NOxing of the solution, or chemically with sulfamic acid), we cannot reduce the gold.

With free nitric acid in solution (oxidizer) as we try to reduce the gold chemically (give the ion electrons) with our reagent such as SMB, or reduce the gold in the stannous chloride test with the tin chloride, the free oxidizer just keeps taking those electrons away, so the gold ions basically do not get a full shell of electrons in the atom, or reduce back to elemental gold.

In the HCl/NaClO method chlorine gas in formed in solution, the chlorine is the oxidizer that needs to be consumed or removed before we can effectively reduce the gold...
Heating this solution can easily vapor off the chlorine, it is much easier than removing the free nitric acid from aqua regia.


Sometimes if the solution contains a very minimum amount of free oxidizer our chemical reagent can consume this little free oxidizing agent in solution (reduce it) with the reaction of our reducing agent used to reduce our gold (SMB or SnCl2 Etcetera), but we will have to add excess reducing agent (SMB), and this does not work when we have too much remaining oxidizing agent (free nitric acid) left in solution when we go to reduce our gold back to metal.

Free HCl remaining in solution is no problem with our gold chloride solution, it cannot re-oxidize the gold, or will not give us a problem when we go to reduce the gold with a reducing agent like SMB.
To insure we do not limit it in the reaction of dissolving the gold we normally use a bit of excess HCl to begin with, but for best results we try to limit the amount of HNO3 used in the aqua regia.

Many times by adding HNO3 in small amounts, and increments as needed and adding more after the reaction is complete on the previous addition of acid, heating the solution to help complete the reaction. 

Free nitric or oxidizing agent can be removed from our aqua regia with several ways, the three evaporation process where we distill off the nitric acid as NOx gas, consuming it all in reacting with our gold, and sulfamic acid to chemically reduce the oxidizer...

Chlorine gas can be easily removed, by its reaction with gold, or with heat or sitting in the sunlight for a long enough period of time to remove the gas from solution.

Leaving a bit of gold at the end of the process is another method to insure we have consumed all of the nitric acid before we move on to the reduction stage to precipitate our gold later.

Harold's trick of using a gold button to consume free nitric acid, can save time with the evaporation process, You do not have to rely on evaporation to drive off the free nitric (like you do with the three evaporation process), as the button of gold reduces the free nitric acid as its gold is dissolved into solution.consumed

Hope this makes sense.


----------



## Photobacterium (Dec 6, 2013)

butcher said:


> Harold's trick of using a gold button to consume free nitric acid, can save time with the evaporation process, You do not have to rely on evaporation to drive off the free nitric (like you do with the three evaporation process), as the button of gold reduces the free nitric acid as its gold is dissolved into solution.consumed
> 
> Hope this makes sense.



I'm here to learn, Thank You for the explanation.

Not "ready for the test" ... taking it a step at a time.

Can a button of copper perform a similar function as the button of gold, in terms of reducing the amount of Nitric to facilitate the Stannous purple blotch indicator ?


----------



## butcher (Dec 6, 2013)

yes most any base metal can consume the free nitric acid,but then you are adding these other metals, but with copper a metal that is a strong coloring agent to solutions it may make seeing a light purple hard to see, also stannous chloride will also reduce other metals from solutions like copper which can give a brown red color.

Another problem of adding copper metal (or any base metals) to your solution, it can donate electrons to those gold ions reducing them back to metal, basically taking your gold out of solution so that your test would no longer have gold ions to test for in the gold to test, and the solution would be a copper solution which could be reduced by the stannous chloride...

For these reasons basically I say you should not use copper in the manner you are asking. 

A bit of sulfamic acid (Home Depot flooring department grout cleaner), added to your test sample, will remove free nitric acid and will not give color to the test like copper would, it will also not reduce the gold.


----------



## Harold_V (Dec 7, 2013)

If you've read enough of Hoke's book, you may understand that copper can be used to recover precious metals that are in solution. For that reason, it's never wise to add any to solutions bearing values unless your objective is to effect a recovery. Using it to eliminate free nitric would not function as you'd hope. 

Harold


----------



## Palladium (Dec 7, 2013)

A little off topic here but sometimes when you don't know how much nitric to use in a given solution you have to overshoot the nitric. One trick i use with a nitric rich solution is to add a copper button to consume the excess nitric much like you would with gold. Copper is a big consumer of nitric acid. Once the solution is free of nitric you will have a small amount of precipitated gold in your beaker that needs redissolved. This will give you a restarting point for adding nitric in increments until your reaction is complete and producing a solution that you can drop the gold from without the added oxidizer interfering.


----------



## artart47 (Dec 9, 2013)

Hi everyone.
Butcher. I'm doing some tests on the dirt that came in the pack of Snowdogs quartz. Also doing some mud from the stock pot. Photob. is sending me a small sample of the mud and I'm gonna see what I can pull out of it. He needs to do some reading before he tackles the task. Per-haps I can give him an idea of how much if any gold is in it.
artart47


----------



## butcher (Dec 10, 2013)

artart47, 
Sounds like a fun project.


----------

