gold suspicious sample

[4metals]

There is a lot of information about tables on the forum, first wait for the results from your panning test and the fire assay on the unpanned ore and a fire assay on the ore that comes out of the pan to see how much fine gold material, if any, came out of the pan.

We await the results of your testing.

 

[Eu_citzen]

4metals is correct, of course. Don't get ahead of yourself.

In my case, a first fire assay was done with 1Kg of sand.
100g is good only for confirming any gold, but not how much there really is in that sand.

To really confirm you're going to get a profit, a much larger sample is highly recommended.
Say, for example, 6Kgs of sand. Concentrate those and then have it assayed.

Also remember to calculate the share with the guy shipping the sand.
If you'll only end up with 1-2 grams at the end of the day, perhaps it's not going to be worthwhile.

Larger samples give better accuracy = less risk of having bought the table/sluice for nothing!

 

[Topher_osAUrus]

...it needs to be wetted by the water on the table and since it had been incinerated it needed a surfactant to help, otherwise it would float on the water. We wet the sample and mixed in a surfactant until it all sank quickly and it was put on the table with assurances by the smiling salesman that in a short while we would be looking at a line of gold on the table. When the brown water cleared, all that was there was the pretty blue color of their table, no gold, not even a hint, just a clean table.

... I remember my professional advice was something like "Take a Valium and chill out!"

Sorry to skew the thread, but a couple questions come to mind.

What was the surfactant used? Proprietary stuff from the mining company?

What about incinerating causes the phenomenon?
And is this something that is cause for concern with escrap?
-I know with bga's and chips, it is suggested to use a drop of dish detergent, but should all incinerated lots have this done?
-and would the surfactant cause possible problems with the next step, if it was direct dissolution in AR?

What was the issue that lead to there being no gold concentrated? Improper setup on the table? Surfactant didn't work well enough?

How bout the valium, did it work? 3ozt lost would break my heart..think I'd be out there with a shovel and pan..

 

[4metals]

The surfactant used was dishwashing liquid.

I think whenever something is dried to the point where the moisture content is negligible, it will naturally tend to not get wet easily and that is why a surfactant is needed to break that surface tension and let the water penetrate easier.

As far as why no gold was collected on the table I have no idea, and the guys at Action Mining didn't either. Maybe a modern table would work, back then the tables were a relatively new technology. I have since come to the conclusion that if it did work a lot of refiners would be using it to cut costs, today a full 55 gallon drum of prepared sweeps cost $2.00 a pound so each drum costs about $1000.00. But no one is using them for this purpose. Actually unless it captures 100% of the values, the per pound charge would be less than the value of the loss so it still wouldn't be cost effective. The modern tables claim to collect gold particles as small as 5 microns so in theory, the table should have caught it. There goes that theory again!

How bout the valium, did it work? 3 ozt lost would break my heart..think I'd be out there with a shovel and pan..

Apparently it worked because he got over it. And I got over it by considering it a learning experience, it sounded good and all of the preliminary indications looked good, and it had the potential to save me a lot of operating expense. And if you never try anything new, you may just spend your life stuck in one place.

 

[g_axelsson]

I just ran into a relevant book, Handbook of gold exploration and evaluation by Eoin H. Macdonald, 2007

It goes in deep into theory about deposits, geology, exploration, mining, planning, recovery and testing in 630 pages. Among things discussed is various gold concentrators like spiral, sluices, tables, centrifugal, jigs and other. With just browsing through it for 20-30 minutes I can't tell much about the details but this goes into my reference library.

Maybe 4metals knows of this book too, it sounds like it would be something he would have in his library.

https://books.google.com/books?id=16CjAgAAQBAJ&pg=PR2&lpg=PR2&dq=Handbook+of+gold+exploration+and+evaluation+Eoin+H.+Macdonald&source=bl&ots=T6fMCaEg-X&sig=FfRxygnKa58O2IYPLuGRXdaJgQ8&hl=sv&sa=X&ved=0ahUKEwjSnrywupTTAhUBOJoKHf04BicQ6AEIUjAG#v=onepage&q&f=false

Göran

 

[Eu_citzen]

Göran, thanks for the heads up on the book! I'll certainly have use of it.

 

[ahmadbayoumi]

Finally, the fire assay completed with negative results.

No traces for any gold in the sample assayed

So this means that the test I made earlier and the purple color I saw was fake

So any explanation for that ?

 

[4metals]

Your original sample was quite small (0.2 grams, I just looked). So even if your material was 1% gold (which assays 10 kilograms per ton, very high) You would only have 2 milligrams of gold in the sample. The result was a very slight color indication which at that low concentration could be caused by any contamination.

Even a fire assayer with all of the right tools would use a much larger sample than 0.2 grams.

 

[Eu_citzen]

Your original sample was quite small (0.2 grams, I just looked). So even if your material was 1% gold (which assays 10 kilograms per ton, very high) You would only have 2 milligrams of gold in the sample. The result was a very slight color indication which at that low concentration could be caused by any contamination.

Even a fire assayer with all of the right tools would use a much larger sample than 0.2 grams.

I agree 100%.