Gravity Separation & Concentration Methods

Gravity Separation & Concentration Methods2017-04-04T06:57:23-04:00
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How to recover silver & gold from rich rocks (6 replies and 5 comments)

1 year ago

I am extremely new to the gold and silver recovery world. My uncle has a plot in New Mexico that we recently realised has some metals in it. We took some samples from various locations around his land and had them scanned and confirmed. It's all inside of rocks and we haven't been able to piece together what our methods should be. We brought 500 lbs of rock samples back and averages about 17% silver and like, 1.7% gold. Other metals that follow those two are in there as well, obviously. What should we do to recover these precious metals? Panning hasn't worked since we have to pulverise the rocks and the colors end up superfine. We know we have to burn off the oxides after we concentrate but so far concentration has been our biggest issue. Any information will help us, we are super novice. Thank you!

Gene Cheeseman
1 year ago
Gene Cheeseman 1 year ago

Are you sure the contents are not 17 ppm Ag and 1.7 ppm Au? 


Those are still decent values but if they are actually in %s just sell the rocks as is and you will be rich men!

1 year ago

I will find out for sure this week. My brother is not known for his overabundance of brains and could have confused ppm for percentage.

Paul Morrow
1 year ago
Paul Morrow 1 year ago

Hello GPD,

Handheld XRF do magic:

500 lbs = 227,272 grams X 17 % Ag = 1250 Oz of Ag X $16/Oz = $20,000
500 lbs = 227,272 grams X 1.7 % Au = 124 Oz of Au X $1250/Oz =  $155,000

$175,000 in metal -- no need to worry about extracting anything here.

As Mr Cheeseman says, sell it as is and pay off your mortgage. 

If you insist on holding gold and silver in your hand, or are really looking for entertainment, buy a

It will feel like a BBQ

PS: don't tell anyone where you get those rocks from.

Have fun!

1 year ago

The man we took it to was a coin guy and he used a mass spec. The print off sheet was read by my brother and he is known for errors like that but I can take another sample up there and find out. Everyone we have ever talked to has told us that it's useless unless we can get it to triple 9's, which is why I came here. I will get more information this week..

1 year ago
SmartDog 1 year ago

First, like others said, if it is at the % level you do not need to concentrate just sell the material.  But it is probably at the ppm level, and even then it would be considered a good ore grade.  As to how to concentrate, that really depends on how the Ag and Au is in the rocks.  The way you phrased your question, it sounds like the metals are in very small particles through out the rock (this would be called finely deseminated).  If so you are looking at either a leaching process or finely grinding the rock and then floating the metals.  In either case you need to arrange lab work to fully get the answer.  

1 year ago

They are huge rocks that we found with huge streaks of colors running through them. I don't know if we can take pictures and put them on this site but I will make a tumblr and show you guys and you can tell me what you think.

Todd H
1 year ago
Todd H 1 year ago

I wish mining was easy but it involves a systematic approach unless you like losing money. Here is how it generally proceeds

  1. Exploration - how much material do you have an what grade is it?
  2. Test work - can the gold be recovered and how
  3. Flowsheet development - equipment selection
  4. Mine plan - how is the ore going to be mined
  5. Capital and operating cost estimation
  6. Environmental - how is waste being handled
  7. Permitting

Even if you have a small project that is just placer gold, you should think about these issues.  The first two are the most important to getting started.



Todd Harvey - Global Resource Engineering

1 year ago
auman 1 year ago

I am new to this site. I have some ore from 2 different location, and are 2 different types of ore.

I am working with high grade ore called Calaverite (telluride).
I have been looking at your instructions on how to dissolve gold of this type using sodium cyanide.
I have seen sodium ferrocyanide. Will this work and dissolve the gold as well?
Also, when the metals are dissolved, is there a way to only dissolve the gold and leave the other metals behind?

Anything related to cyanide is near impossible to buy here in the states.

The second type of ore is Carlin Type from Nevada.

Both of these ores I will begin by roasting. Its after that where I can figure out chemically how to get the gold.



11 months ago

Contact me about your calaverite.

11 months ago
11 months ago
Ali01 11 months ago


I'm new in this field..found some rocks from my construction me for lab tests for any worth thing in it..


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