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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[arizau]

OK, I have two runs. I cut the rods with a hacksaw, but left the little pieces in the tumbler with the larger rods. I could only get about 1/3 critical speed (about 45 rpm) vs the numbers above. I calculated the total volume and 2.7 Tbs was 5%, so I went with 3 Tbs of cons and 3 Tbs of water. You can see the picture of the tumbler with rods and then with rods and cons. View attachment 1163532View attachment 1163533


I thought I was running +60 mesh, but in fact ran +40. When I ran the first sample 60 minutes and put it though the 60 mesh screen, a fair fraction went through!! So the rod mill had reduced the size of the particles. Not knowing that I used +40, I ran the next sample 2 ½ hours. Then I discovered my mistake.

So, I am sorting through the results, but a couple of things for sure—the rod mill did reduce the size of the black sands. Also, I have flattened gold that floats very easily because it is so thin. Jet Dry was mandatory because even the larger pieces you see here floated with it.

View attachment 1163535

Just a thought....I'm guessing that there is a rubber inner liner in the cylinder but, is it removable/replaceable? Some models note that as a feature. You will get a more efficient grind with full hard surface contacts between the rods and cylinder if you can run it sans liner. Make sure the cylinder still seals properly.

Good luck.

 

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[GoldpannerDave]

I wanted to stop back in here and congratulate you guys on the progress you have made with your experimentation with the original equipment concept.
I tend to be a bit ridged in my thinking sometimes as some of you may have noticed earlier in the thread.
Anyway ... Good work guys on making great contributions to the concept..... keep up the good work.

Thank you. We are making some progress and again, I wish to thank you for bringing Randy Clarkson's presentation to this board. Like it or not, you had a huge hand in getting us started. I do appreciate it...and you checking back in with the thumb's up. That is big in my book; given your earlier position. Peace and may your beach sand be loaded with gold. And those 120, 90, and 60 micron screens do work. See photos below.

 

[GoldpannerDave]

Rubber liner? It is its own liner because my entire barrel is made of rubber. Good idea, though; I am looking for alternate tumbler barrels, thanks to Ducky's comments (in a PM). You guys are all amazing--you just keep coming up with great suggestions for improvements.

 

[GoldpannerDave]

More pictures! Here are pictures of the material from the first run. You can see most everything went through the 40 mesh screen, though the material was originally +40. The 60 mesh screen has most of the resulting material. The 120 microns (about 112 mesh) also has a great deal of material in it. Some made it through to the 90 microns (150 mesh) and a tiny bit on to the 60 microns (about 256 mesh). A few particles (20 maybe) went through the last screen.

There doesn't appear to be any gold on the 40 screen, so I milled it too long or there was no 40 mesh gold in the sample. There is too much black sand still on the 60 mesh and the 120 micron (112 mesh) screens to see much gold, but I can see two specs on the 112 mesh. There are a few specs in the 90 micron (150 mesh) around the edge and it is very hard to see any gold in the 60 micron (256 mesh) screen.

So rather than pan the +60 fraction, I am going to run it 15 minutes and re-screen it.

Sorry about the photo quality; I used the macro which allows me to get real close, but it is supposed to be used in bright sunlight. It rained here all day, so I needed the flash, which because it was close, caused the color changes.

 

[GoldpannerDave]

Well, 15 more minutes did not make it leave mostly gold on the +60 side with most of the black sands going through.

I panned the +60 fraction just to check and there were 10-12 nice flattened pieces of gold, but the black sands had not been milled enough to allow them to pass through the 60 mesh screen in a large enough quantity yet.

 

[GoldpannerDave]

Sorry, guys; no more updates until Tues at the earliest. Out of town till then.

 

[davin]

sounds good.

 

[bfloyd4445]

still wont get all fine gold like mercury will

 

[KevinInColorado]

still wont get all fine gold like mercury will

If only it were so simple. The gold we are getting this way wouldn't be recoverable with mercury before running thru our little mill due to the gold being coated with other minerals. So this is getting different gold than what mercury would get...not that you need Merc to get fine gold...classification and panning works fine for that in my workshop.

 

[Duckwalk]

Same I constantly pan 100 mesh or smaller locally.

 

[GoldpannerDave]

OK. I had 1 Tbs left of +40 cons and decided to run it with 1 Tbs water in my rock tumbler. I ran the material 30 minutes. Virtually nothing left on the 40 mesh screen (see photo) and not a great deal on the 60 mesh screen. Too much to see gold on the screen. So I have not found the right parameters yet. Almost everything went through the first screen, but after panning, there were only 3 (three) +40 specs of gold left in that fraction. So it was ground too much because everything went through, including the gold. Most of the material you see in the leftmost screen (40 mesh) is not black sand, but quartz sand that has been stuck in it for some time. The black sand is in the shadow and along the lower left edge; virtually nothing. The other is 60 mesh. More testing needed. Sigh.

The pictures are a peak on the way to Steamboat Springs (left). The other is coming home, going over Rabbit Ears Pass with fresh snow from over the weekend.

 

[GoldpannerDave]

Here is 1 Tbs of +60 with the gold panned out to one side. I can going to run this 15 minutes and see what it looks like when I screen it with 60 mesh. Hopefully, the black sands go thru and at least some of the gold remains. Right now some of those 15-16 specs will almost go though the 60 mesh screen. Some are clearly flattened because I ran this before. The gold pieces are to the upper right of the wheat cent. You will have to enlarge the picture, but I think you can see them OK when you do.

 

[GoldpannerDave]

Here is 1 Tbs of +60 with the gold panned out to one side. I can going to run this 15 minutes and see what it looks like when I screen it with 60 mesh. Hopefully, the black sands go thru and at least some of the gold remains. Right now some of those 15-16 specs will almost go though the 60 mesh screen. Some are clearly flattened because I ran this before. The gold pieces are to the upper right of the wheat cent. You will have to enlarge the picture, but I think you can see them OK when you do.

View attachment 1169010

Here are the results of 20 minutes additional tumbling. This is +60 and you can see the colors are flattened; one looks like wire gold now. I think the colors show pretty well if you enlarge the picture. However, there was still way too much black sand remaining on the +60 screen. More studies still needed.

View attachment 1169407

Just to let you see how beautiful it is here today, I have added a snapshot of Pikes Peak from out my back door.

 

[KevinInColorado]

Dave, I think you're getting good results and you may want to set aside the goal of having +60 gold without only -60 sand. May just be unrealistic with our simple gear.

 

[arizau]

Without significant centrifugal force (you estimated 45% critical speed) the setup is relying mostly on the individual weight of each rod (or have you already added more since your pictures) to flatten the gold and grind the waste and this is against a soft cylinder. As you probably already know you need a force multiplier....More rods so they have to stack thus multiply the psi of the contact points of the bottom rods. I know you have already said you need to add more when you get a chance but you might even be able to utilize sand filled and corked (maybe with pieces of a wooden dowel) sections of pipe.

Thanks for your progress reports.

Good luck.

 

[GoldpannerDave]

Dave, I think you're getting good results and you may want to set aside the goal of having +60 gold without only -60 sand. May just be unrealistic with our simple gear.

Yes, I have about decided that -- or up my speed to the required 70% or so of the critical speed, as arizau noted or increase the number of contact points.

 

[GoldpannerDave]

Without significant centrifugal force (you estimated 45% critical speed) the setup is relying mostly on the individual weight of each rod (or have you already added more since your pictures) to flatten the gold and grind the waste and this is against a soft cylinder. As you probably already know you need a force multiplier....More rods so they have to stack thus multiply the psi of the contact points of the bottom rods. I know you have already said you need to add more when you get a chance but you might even be able to utilize sand filled and corked (maybe with pieces of a wooden dowel) sections of pipe.

Thanks for your progress reports.

Good luck.

Thanks, arizau; good idea about hollow, filled pipes. I have chatted with Ducky on increasing the speed of my tumbler. I have also looked online at homemade tumbler options. Reloaders do a lot of tumbling and so there are a lot of options out there to look at. Until I make changes, I likely have done about all I can for now, as Kevin commented. However, I was really interested to see what looked like wire gold and enlarged, flattened colors in my last trial as compared to their before condition.

I may just run a few more tests and see how well the mixture cleans up on my Miller table. That should be easier than panning as I have done so far. It is just that my Miller table is not continuously set up in the garage so it has been quicker to pan to see results. I do have to admit that to a great extend, this technique is working--I am crushing a majority of the black sands and also flattening many of the colors in my cons. I will probably try some of the finer screens with my current setup. So far, I have been using mostly my 40 and 60 mesh screens.

 

[arizau]

Hmm. I think I am right here. If your tumbler operates with the container resting between a powered roller and an idler roller then you can increase rotational speed by simply reducing the diameter of the cylinder (think peanut butter jar, hiking type plastic water bottle, etc.).* If the increased speed tries to eject the cylinder you may want to improvise with a couple of loose straps to keep it in place. You also may need to add something to the outside of the bottle to increase friction so the bottle keeps up with the rollers. The old style rubberized cloth plumbers tape comes to mind for this.

I know. I'm a pest. Just jealous that I don't have the equipment or the concentrates to play with this myself.

Good luck.

* You will need to re-do calculations as to critical speed and the amount of charged material.

 

[Goodyguy]

You guys may also want to try a process utilizing Oleophilic Adhesion. I learned this technique from a fellow prospector that I met at one of my favorite gold bearing creeks.

It's a very simple cheap, fast and fun way to recover fine and micro sized gold from your -30 and smaller concentrates.

Simply smear a thin smooth layer of petroleum jelly (Vaseline) onto a flat smooth slick plate.
Hold the slick plate under water in a tub or if in the creek with a safety pan underneath it and shake the slick plate back and forth while pouring your wet concentrate through a sieve above it.

The gangue will not stick to the petroleum jelly however the gold will stick due to its oleophilic nature.

To remove the gold imbedded jelly from the slick plate use a body filler spreader to swipe off the petroleum jelly and then swipe off the spreader into a small jar.
To recover the gold from the jelly just use charcoal lighter fluid in the jar and shake it to dissolve the petroleum jelly. Simple as that!

The prospector I met was using this technique at the creek and my curiosity got the best of me so I had to ask what he was doing. Turns out he is a contributing writer for ICMJ's Prospecting and Mining Journal along with other publications. His name is Alex Dolbeare and the ICMJ issue that this technique was featured in detail was Volume 83 Number 8 April 2014

Go for the Gold
GG~

 

[johnedoe]

You guys may also want to try a process utilizing Oleophilic Adhesion. I learned this technique from a fellow prospector that I met at one of my favorite gold bearing creeks.

It's a very simple cheap, fast and fun way to recover fine and micro sized gold from your -30 and smaller concentrates.

Simply smear a thin smooth layer of petroleum jelly (Vaseline) onto a flat smooth slick plate.
Hold the slick plate under water in a tub or if in the creek with a safety pan underneath and shake it back and forth while pouring your wet concentrate through a seive above the slick plate.

The gangue will not stick to the petroleum jelly however the gold will stick due to its oleophilic nature.

To remove the gold imbedded jelly from the slick plate use a body filler spreader to swipe off the petroleum jelly and then swipe off the spreader into a small jar.
To recover the gold from the jelly just use charcoal lighter fluid in the jar and shake it to dissolve the petroleum jelly. Simple as that!

The prospector I met was using this technique at the creek and my curiosity got the best of me so I had to ask what he was doing. Turns out he is a contributing writer for ICMJ's Prospecting and Mining Journal along with other publications. His name is Alex Dolbeare and the ICMJ issue that this technique was featured in detail was Volume 83 Number 8 April 2014

Go for the Gold
GG~

Well who'd a thunk it...... Never considered anything like that ...... Thank's for the info, will look into that closer.