Simple solution to fine gold recovery

[johnedoe]

This was developed by Randy Clarkson, an expert in gold recovery designs.

A simple gizmo to help miners snag lost gold..... New gizmo could help placer miners snag lost gold | Yukon News

Also this by Randy Clarkson on fine gold recovery which is somewhat misleading in that this is mostly about commercial ops and 1" minus classification is considered fine....... The Clarkson Study Fine Gold Recovery

Here is a PDF presentation of the process....... http://www.geology.gov.yk.ca/pdf/141114_Nov1014_Grinding_for_Gold_Presentation.pdf ....... Thank you arizau for finding that PDF

Enjoy the learning.

 

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[GoldpannerDave]

Just go to the store to measure the cap diameter silly...you know you're going to buy em anyway just to try this! Also it'll fit tight enough that you don't need to worry much about leakage with just a press fit assembly.

I will but it was late last night and I was hoping to find that info on the Internet, but could not. I was hoping to find out and do some calculations on criitical speed last night.

As far as leakage, I also thought of putting a piece of cut rubber, like a gasket over the end of the PVC before shoving the cap on, if needed.

Yes, I will go buy some 3" PVC and caps today if I get a chance. I guess figured somewhere out there, someone knew. It seems someone on Treasure Net always knows whatever it is you need. This is a great place.

 

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[arizau]

I just posted this request for information on "PVC cap size information needed, please" in the Panning Section (where this thread is)

The rubber tumbler barrel is so much larger in diameter, that at least the rods I am using will work better in a 3" inside diameter vs about 4.5" for the current setup. And perhaps the speed will increase some, though I may have to do something else about that part.

The 3 5/8" gap is problematic but....Have you considered just inserting another smaller cylinder inside the one you have? You could also use another section of pvc of about equivalent size as the primary cylinder. An inner cylinder would then roll at increased rpm the same as if it were mounted on the rollers. If the inner cylinder will clear the end assembly you can add length to increase volume too. If the inner cylinder will not clear maybe sleeve it so it will.

Friction fit pipe caps are hard to remove so if you can find something with a screw cap then that is the way to go.

PS: One of the catalogs for lab supplies that are probably available to you may give you some options for different sized and maybe hard plastic containers suitable for your use.

NOTE: I edited out some of what I had previously posted here since I think I was wrong. Sorry.

 

[arizau]

Also O-rings could be used to increase the height of the inner cylinder if you can find the right sizes.

 

[KevinInColorado]

They do make screw in plugs for PVC, that is a GREAT idea because I agree a friction fit cap may require a wrench to remove...then again the screw plug will too.

 

[GoldpannerDave]

Also O-rings could be used to increase the height of the inner cylinder if you can find the right sizes.

Yes, I like this also because the 3" mechanical [expanding] plug mentioned in my question thread by Mike(swWash) is 3.500 inches outside diameter, same as the PVC, so I need to make the size a bit larger (3 and 5/8"). So now I have a shopping list to get: 3" PVC pipe, 1 cap for one end and the expanding plug for the other; O-rings to expand the size to fit the rollers.

 

[GoldpannerDave]

The 3 5/8" gap is problematic but....Have you considered just inserting another smaller cylinder inside the one you have? You could also use another section of pvc of about equivalent size as the primary cylinder. An inner cylinder would then roll at increased rpm the same as if it were mounted on the rollers. If the inner cylinder will clear the end assembly you can add length to increase volume too. If the inner cylinder will not clear maybe sleeve it so it will.

Friction fit pipe caps are hard to remove so if you can find something with a screw cap then that is the way to go.

PS: One of the catalogs for lab supplies that are probably available to you may give you some options for different sized and maybe hard plastic containers suitable for your use.

NOTE: I edited out some of what I had previously posted here since I think I was wrong. Sorry.

One problem with the smaller diameter inside the current rubber barrel is that the critical speed needed goes up, so it is almost a lose-lose situation.

 

[mytimetoshine]

Has anybody been trying this latley?. If so please post some pictures.
I've built up a decent amount of sands now I want to try it. I was thinking of getting a clean empty 1 gallon paint can with lid for the drum. I might even try it out with no motor. Just put it on some rollers and see what happens.

 

[KevinInColorado]

I haven't run mine lately but I did just finally get some larger diameter rod which I'm eager to cut to size and try

PS going without a motor sounds interesting. 75 rpm for 10-15 minutes will be a workout!

 

[mytimetoshine]

I haven't run mine lately but I did just finally get some larger diameter rod which I'm eager to cut to size and try

PS going without a motor sounds interesting. 75 rpm for 10-15 minutes will be a workout!

Good news! I love to work out! Lol.

I figured I just wan to see if it will work for me and my sands. I'm not very good at technical stuff like trying to buy the "right" motor and get it spinning my drum at the correct rpm. I feel like it will be easier and cheaper to get the 75 rpm by hand. Then IF it's working I can think about upgrading to a motor. I think the bigger challenge will be counting the reps while busy spinning it manually... Keep us updated on your progress Kevin !

 

[GoldpannerDave]

Has anybody been trying this latley?. If so please post some pictures.
I've built up a decent amount of sands now I want to try it. I was thinking of getting a clean empty 1 gallon paint can with lid for the drum. I might even try it out with no motor. Just put it on some rollers and see what happens.

Sorry, I got behind with the start of school (the Air Force Academy starts the first week in August). I did get out with KevinInColorado to test the AMP sluice. Since then, I have been trying to get my Gold Hog Washer mats zeroed-in in what time I had left. Ducky sent me a better motor (Thanks again, Ducky) and I have a dead printer to use as the base for running my tumbler at higher rpms. I still need to get some larger rods and then once things settle down I will work some more on trying to flatten the gold out to allow my to separate it better.

Thanks for bringing the thread back to the top!

 

[Duckwalk]

Sorry, I got behind with the start of school (the Air Force Academy starts the first week in August). I did get out with KevinInColorado to test the AMP sluice. Since then, I have been trying to get my Gold Hog Washer mats zeroed-in in what time I had left. Ducky sent me a better motor (Thanks again, Ducky) and I have a dead printer to use as the base for running my tumbler at higher rpms. I still need to get some larger rods and then once things settle down I will work some more on trying to flatten the gold out to allow my to separate it better.

Thanks for bringing the thread back to the top!

Ugh i keep getting forgetful... do you still need a 12v brushless fan for your motor?

 

[GoldpannerDave]

Ugh i keep getting forgetful... do you still need a 12v brushless fan for your motor?

Probably, Ducky, but for now I can point a regular fan at it to keep it cool. When I get back to working on it, I will be in touch. Thanks.

 

[arizau]

Here is the final report published by Randy Clarkson, the developer of the process that this thread is about. I looked back to see if this report had been mentioned before but, unless I missed it, it has not. My apologies for duplication if it has been. Here is the link. http://kpma.ca/assets/files/grinding-for-gold-report.pdf

 

[johnedoe]

Here is the final report published by Randy Clarkson, the developer of the process that this thread is about. I looked back to see if this report had been mentioned before but, unless I missed it, it has not. My apologies for duplication if it has been. Here is the link. http://kpma.ca/assets/files/grinding-for-gold-report.pdf

Thank's arizau for putting this in here..... good stuff...
If there is any duplication no worries.... redundancy is not necessarily a bad thing..... I find my self doing that all the time, course I'm told that is what comes with my advancing years........

 

[GoldpannerDave]

Here is the final report published by Randy Clarkson, the developer of the process that this thread is about. I looked back to see if this report had been mentioned before but, unless I missed it, it has not. My apologies for duplication if it has been. Here is the link. http://kpma.ca/assets/files/grinding-for-gold-report.pdf

No, this particular report has not been. Thanks very much for linking it.

 

[mytimetoshine]

So I bought the red Chicago rock tumbler twin drum model. 2×3lb for $60 bucks with shipping on Ebay. I decided to buy because my daughter and I have an interest in tumbling rocks ( which turns out is a 4 week process! :/ and I bought a set of grit for 15 bucks.. little did I know that was only enough for 1 run. Is that right?!?!?! Or did I get ripped off? Seems damn expensive to polish a handful of rocks. )

I was hoping to maybe use it for my rod mill. My drums are rubber and I would prefer to use metal but I'm sure it would still work. Problem is I just counted the rpm and it's only 50...72 is what you need right?

 

[arizau]

So I bought the red Chicago rock tumbler twin drum model. 2×3lb for $60 bucks with shipping on Ebay. I decided to buy because my daughter and I have an interest in tumbling rocks ( which turns out is a 4 week process! :/ and I bought a set of grit for 15 bucks.. little did I know that was only enough for 1 run. Is that right?!?!?! Or did I get ripped off? Seems damn expensive to polish a handful of rocks. )

I was hoping to maybe use it for my rod mill. My drums are rubber and I would prefer to use metal but I'm sure it would still work. Problem is I just counted the rpm and it's only 50...72 is what you need right?

The calculation for critical speed/RPM is dependent on the inside diameter of the cylinder and there is a formula in the report to help you determine what you need for ideal grinding. I suspect that some advantage can be gained by grinding at slower speeds and both GoldpannerDave and KinC both reported that was the case if I remember correctly. Keep your concentrate loads relatively small and use a heavy load of various sized/diameter rods for best effect in my opinion.

Good luck.

 

[KevinInColorado]

Right. The ideal rotation results in the rods riding up the wall of the drum and then falling to land on other rods. If the drum runs too fast, the rods ride around the top in a loop-de-loop without falling. Too slow and they just roll at the bottom of the drum. If you aren't getting any falling action, you could put some screws into the drum from the outside to make a little wall that carries rods up further so they fall. I tried this and it worked. Remember that a smaller drum will have more rpm than a larger drum (on a given set of rollers) so you can vary rpm by just using a different diameter drum...I had to go smaller on the drum to get the desired tumbling action for my rods using the rollers I harvested from a printer.

Clarkson says to fill the drum 45% full with rods (if memory serves) but I did fine with much less.

He also says to limit the amount of material per batch. I think this is because you want a thin layer of material between the rods to get good crushing/pancaking action on the gold. I totally agree, seems to me that large amounts of material would limit rod tumbling and cushion the fall of each rod reducing the crushing.

He says to limit your run time so as to avoid busting your little gold pancakes into tiny pieces. Makes sense to me but I think ideal run time may vary depending on weight of your rods...big rods means short run times per batch (less than 10 minutes). I need to run some more tests to confirm this so I'd love to hear from others with experience.

Finally, Clarkson says to run material wet. I can't figure out why this is important. I've had good success dry and cleanout of the drum is quick with dry material...when wet you have to rinse all the rods and they get rusty, adding more iron material to your sample.

 

[arizau]

("He says to limit your run time so as to avoid busting you little gold pancakes into tiny pieces. Makes sense to me but I think ideal run time may vary depending on weight of your rods...big rods means short run times per batch (less than 10 minutes). I need to run some more tests to confirm this so I'd love to hear from others with experience.")

No experience here, just some analysis. Only larger rods equals less rod to cylinder contact at every point in time due to the stand off distances between the rods compared to a mixture with smaller rods having more potential for more contact surfaces at any given point in time. More surface contacts (probable shorter run times) with a mixture may reduce the potential for gold size degradation and is what Randy uses or suggests.

("Finally, Clarkson says to run material wet. I can't figure out why this is important. I've had good success dry and cleanout of the drum is quick with dry material...when wet you have to rinse all the rods and they get rusty, adding more iron material to your sample.")

Running dry is more abrasive and may further reduce/degrade the size of the gold while running wet promotes specific gravity classification/separation/spreading eg. dry mixes indiscriminately perhaps leading to mostly equal sized, smaller, particles (gold and waste) and wet separates by space and specific gravity allowing gold to flatten and not be ground down while waste is simply reduced.

The above are just my perceptions but I think they are correct.

 

[johnedoe]

The other reason for the short run time is so the gold doesn't actually start coating the rods....... Also a result from overloading.....
This is from the first PDF... http://www.geology.gov.yk.ca/pdf/141114_Nov1014_Grinding_for_Gold_Presentation.pdf