Help with gold ore

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eaglewings35

Well-known member
Joined
May 27, 2010
Messages
205
Ok Gents, I've seen many posts about people needing to know how to process gold ore.
My friend and I have sent off a 6 lb sample for an assay. The results are added here.
To begin, my friend has tried several times (before the assay was sent) to melt some of the gold that he collected out of the same batch. He said that he wasted 2 cans of Mapp gas, and it still wouldn't melt. What would keep the gold from melting?
Also, his crucible has turned blood red and purple in places. I have not tried to melt any yet. I have ran a batch of the ground (powder) quartz in HCl and bleach to dissolve any and all of the flour gold.
My solution turned orange which I believed to be iron (this later confirmed by assay)
I tested the solution with a fresh batch of Stannous and there was no color change at all.
So either there was no gold, or there was something in there preventing the gold from representing.
Now, I know there are oxides present but I don't know how to deal with them, other than roasting. So, Harold, Butcher, and all who know.... by looking at the assay results can you advise me on how best to separate the gold, platinum,Palladium, and silver?

Here are the assay percentages.....
Fe......46.3%
Cu.....7.4%
Zn......16.4%
Pb......3.2%
Mo......15.2%
Ru......4.1%
Ag......7.5%
Au......12.7%

Thanks for the help and advice.
Kerry
 
No sir there isn't.
I was asking about then also because given the history of the immediate surrounding
claims, there is Palladium and platinum in the close proximity.
 
eaglewings35 said:
Here are the assay percentages.....
Fe......46.3%
Cu.....7.4%
Zn......16.4%
Pb......3.2%
Mo......15.2%
Ru......4.1%
Ag......7.5%
Au......12.7%

Thanks for the help and advice.
Kerry

112.8% total sum?
That is quite the ore, good sir.
 
Ok, I did a wiki search and I believe I have found out why my friend had such trouble
melting his gold. Mo which is what is added when making steel, is the 6th highest melting point of all the naturally occurring metals.
So, how is this dealt with? How is this element avoided so the gold can be gotten to?
 
I think you will have to wait for Lou, or a member that deals with ores. That is a lot different than e-scrap or jewelry. Or search the forum, as it may have been discussed before.
 
Topher_osAUrus said:
eaglewings35 said:
Here are the assay percentages.....
Fe......46.3%
Cu.....7.4%
Zn......16.4%
Pb......3.2%
Mo......15.2%
Ru......4.1%
Ag......7.5%
Au......12.7%

Thanks for the help and advice.
Kerry

112.8% total sum?
That is quite the ore, good sir.
You know Gopher, I hadn't even looked at the addition. Plus I've never seen
an assay before. I got these numbers from my friend, he is in Nevada where he has his assay done.
I'm gonna have him check his numbers.
But any advise on how to process would be super !!
 
Hehe
It happens

From the wiki:
"Molybdenum does not occur naturally as a free metal on Earth; it is found only in various oxidation states in minerals. The free element, a silvery metal with a gray cast, has the sixth-highest melting point of any element. It readily forms hard, stable carbides in alloys, and for this reason most of world production of the element (about 80%) is used in steel alloys, including high-strength alloys and superalloys.

Most molybdenum compounds have low solubility in water, but when molybdenum-bearing minerals contact oxygen and water, the resulting molybdate ion MoO2−
4 is quite soluble. ."

Im sure there are several ways to get the metal out of it though.
Maybe adding more lead as litharge, then cupeling
Or maybe just adding more silver and melting.

Just ideas, not claiming they are the best way, or even the right way

Edit to add
...but, the assay numbers dont even report the silicon of the quartz
 
You are absolutely right, and I totally missed that.
That's a head scratcher there. Now I wonder about the validity of that man. This guy is a "Gold Broker" I think I'm going to send a sample to someone different for another assay.

Any body on this forum do spectrograph analysis assays? Would this type of assay be best for determining exact content of my sample?

Kerry
 
Jim is 100% right.
Lou is your man, or one of our ore guys.

I just saw the numbers and a couple bells started dingin upstairs.

Hopefully he isn't trying to take you for a ride.
 
Ok, I called my friend in Nevada and had him read the assay. I believe this reading was done on an XRF. I say this because on the top of the assay reads "Jewelry Type"
Now I've never had any assay done, so I am just speculating. Would the XRF omit the obvious, quartz silica? I would still like to send off for another assay. I've heard about another man called Ray Grimmer. He list on his website an "Atomic Absorbtion Finish".
I'm not sure what this test entails but I will find out, and post it here.
 
112% ... you are sure that the result wasn't in ppm for the gold and silver?

XRF is inherently bad if the software doesn't check for all elements. For example if it is a software pack used for analyzing jewellery only and not geological samples. As pointed out, there is no oxygen or silicon listed so something is missing.
XRF gets confused if there is elements present that it doesn't recognize and it tries to match the measurement to it's known elements.

What type of ore is this? Sulfide? Oxide? Silicate or with a lot of carbonates? Was the assay done on a concentrate or raw ore? Was it treated in any way, for instance roasted?

The more details you can give the bigger chance that you are getting good advice.

This weekend I picked up a large mineral collection (1700 specimens, 0.5-1 ton) with several gold and silver specimens. Among the large pieces was a cut slab from a rich gold ore, up to 15 gram/ton. 12.7% gold would correspond to 127 kg per ton and in my view an unrealistic number when talking gold ores.

Göran
 
g_axelsson said:
This weekend I picked up a large mineral collection (1700 specimens, 0.5-1 ton) with several gold and silver specimens. Among the large pieces was a cut slab from a rich gold ore, up to 15 gram/ton. 12.7% gold would correspond to 127 kg per ton and in my view an unrealistic number when talking gold ores.

Göran

Will there be a show and tell? :)
 
Topher_osAUrus said:
g_axelsson said:
This weekend I picked up a large mineral collection (1700 specimens, 0.5-1 ton) with several gold and silver specimens. Among the large pieces was a cut slab from a rich gold ore, up to 15 gram/ton. 12.7% gold would correspond to 127 kg per ton and in my view an unrealistic number when talking gold ores.

Göran

Will there be a show and tell? :)
There will even be a new website for selling off most of the material. The best specimens I will keep in my own collection. It will probably take more than a year to sell off and several months before I have made a complete inventory.

Maybe I make a thread about it later on.

Göran
 
A simplified scheme, combining aspects of the classical fire-assay with an atomic-absorption finish, is presented for the determination of gold and silver in ores and concentrates. The lead assay button is scorified to approximately 2 g and then parted in nitric acid.

The filtrate is analyzed by AAS for silver; the residue is dissolved in aqua regia and subsequently analyzed for gold by AAS. The precision and accuracy of the method have been established by application to four diverse certified reference materials. The proposed method eliminates the need for such time-consuming steps as inquartation, multiple scorifications, and cupellation.
 
The sticky at the top of this section has ton's of information on how to do quick field tests on all kinds of ores. I've even used a couple myself and I know next to nothing about ores.
 
g_axelsson said:
112% ... you are sure that the result wasn't in ppm for the gold and silver?

XRF is inherently bad if the software doesn't check for all elements. For example if it is a software pack used for analyzing jewellery only and not geological samples. As pointed out, there is no oxygen or silicon listed so something is missing.
XRF gets confused if there is elements present that it doesn't recognize and it tries to match the measurement to it's known elements.

What type of ore is this? Sulfide? Oxide? Silicate or with a lot of carbonates? Was the assay done on a concentrate or raw ore? Was it treated in any way, for instance roasted?

The more details you can give the bigger chance that you are getting good advice.

This weekend I picked up a large mineral collection (1700 specimens, 0.5-1 ton) with several gold and silver specimens. Among the large pieces was a cut slab from a rich gold ore, up to 15 gram/ton. 12.7% gold would correspond to 127 kg per ton and in my view an unrealistic number when talking gold ores.

Göran
Goran, I know next to nothing about ores, just what I've read on Wiki and here on the forum. What I understand he is following a quartz vein, and he said there are alot of sulfide
s. I was just now working on the sample he sent me. The assay said that it had a large amount of iron. I used a magnet and removed about half the volume. It was loaded with iron. And no, there was no roasting before the assay was done. The sample was raw ore, crushed down to a powder and concentrated. I do not know what type of assay this was. What I found today.... I just bought a new Falcon MD20. As I was pulling out the iron with a magnet I was also picking out small rocks that were larger than the ground quartz. I have never been so impressed with any other detector. This falcon was going off on every rock I put it on. I thought we'll I just don't have it tuned in right, I has a couple of very small white quartz slivers that was causing the detector to sound off. I looked at the sliver with my 40X loupe and there it was a couple of specks of gold that my naked eyes couldn't see. I'm having alot of fun with this !!
 
If there were a lot of sulfides then there should be a lot of sulfur in the assay. So we have a lot of % that isn't counted in the XRF so 112% is still not all there is or the sulfur is included as another metal as the program is trying to make sense of the measurement. In any way, the XRF numbers are provably wrong.

Göran
 
Is there any members here on the GRF that do a complete assay?
I checked into sending it to Ray Grimmer and his site says that for an AA assay it costs $60.
A little too high for my budget, but if there isnt anyone here that can do it, I will have to go with him.
It needs to be done so I can know how to work this.
 
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