Grease Table Experiment

[Goldwasher]

the grease will literally help the fine gold through the system...Theres a reason a wash plant operator will lose their mind if all of a sudden they notice a bearing seal leaking grease into a sluice run

just sayin'

 

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[johnedoe]

I have an article from the mining journal about this someplace...
http://www.treasurenet.com/forums/p...50-black-sand-regular-sand-3.html#post5431490

 

[Clay Diggins]

The principles of oleophilic adhesion and hydrophobicity are exploited extensively in modern mining.

The fact that many sulfides of metals like pyrites, galena, tin, manganese, graphite etc. are both hydrophobic and oleophilic allows processing with oils and water to float the oleophilic mass to the surface of the water. This enables separation of the metal sulfides from the dross. It's called froth flotation and it's a good part of what makes the mining industry productive.

Metals that have combined with sulfur can, and usually do, form as sulfides. Virtually all mined metals are found as sulfides. Sulfur is the 10th most common element in the universe. In a mineralized area, like where gold is found, sulfides are very common. Much more common than free gold.

Yeah the mining industry found out that oil and grease float and so do the oleophilic and hydrophobic sulfides when they are attached to that grease. Grease and sulfides love each other just like gold and grease love each other. That's why most of the other heavy minerals in your concentrates besides gold stick to the grease too. And the whole mess wants to float the more it's exposed to air and water.

The effects of oleophilic adhesion and hydrophobicity have been known for centuries. This isn't something new or unknown. Gold loves grease and grease floats. The minerals most often associated with gold also love grease. With the right chemistry and some agitation you can get all those metals to float with the grease. Any miner who has ever put an oily finger in their pan with fine gold learns very quickly that the fine gold will float on the surface and be lost.

Doing it the other way around is hopeful but goes against well known physical and chemical principles. Separating free gold from other associated minerals by specific gravity sorting is a well known process but trying to mix grease into that process is contradictory at best.

Every now and then it's a good thing to check and see if a bicycle goes faster when it's upside down. You never know physics might just change while we aren't looking. Every now and then going against common knowledge can produce surprising results. Your results were as expected. Thanks for trying though and thanks for sharing your results.

Heavy Pans

 

[Capt Nemo]

the grease will literally help the fine gold through the system...Theres a reason a wash plant operator will lose their mind if all of a sudden they notice a bearing seal leaking grease into a sluice run

just sayin'

I didn't have any problems with gold float and oils, so it's not that. I expected to see some float after the run from the grease sheen on the water after the runs, but none was present. I'm starting to think it's due to the speed/angle of the table. I have to run steep at 5 degrees to keep the water as a sheet over the grease, otherwise, it just channelizes and doesn't cover the grease completely. Length of run might also be a factor, as I was only running 10" of capture area. The table did catch pieces of similar size to the losses, so it can capture it, but just not efficiently. Do remember that, the gold ran in this experiment was tailings from a miller table, so it is gold that's hard to capture in the first place. If I had run my concentrates over this instead of the miller table first, we'd be looking at roughly a 95%+ capture rate. So we really are pulling out 60-70% of material that should be going to cyanide leach. Really, you're going to loose the same material with a bazooka, so actually it's doing pretty good even though it sounds bad. Once gold gets down to -200 there's not many tools that are truly effective. The pan seems to be the only thing! The only thing I don't like about the table is messing with all the grease at cleanup.

So all in all, this grease table is actually better than a miller table at capture, as it caught 60-70% of gold that left the miller table. My only letdown is that it's not the mythical 100% capture. I just found a messy better mousetrap.

Can anyone provide rough 0.5-3mm diamonds to test?

 

[johnedoe]

ClayDiggens....
Order the back issue and give it a read.... It will explain a good deal of what you are missing in your assessment.
Also the use of a heavy grease / Vaseline / butter ? is to creat a sticky bed not a floating oily film.
Also the author found that there was not 100% collection but it was still quite high and the gangue material would not stick to the vaseline with only a few exceptions... He did not say what the mineral was in the article.
https://www.icmj.com/magazine/article/recovering-fine-gold-with-oleophilic-adhesion-3041/

 

[Clay Diggins]

Can anyone provide rough 0.5-3mm diamonds to test?

You might want to give Ken a call. He is one of many suppliers of boart diamond. Generally industrial diamonds are a very affordable way to get a good sample of sizes and shapes of diamond.

Heavy Pans

 

[Clay Diggins]

ClayDiggens....
Order the back issue and give it a read.... It will explain a good deal of what you are missing in your assessment.
Also the use of a heavy grease / Vaseline / butter ? is to creat a sticky bed not a floating oily film.
Also the author found that there was not 100% collection but it was still quite high and the gangue material would not stick to the vaseline with only a few exceptions... He did not say what the mineral was in the article.
https://www.icmj.com/magazine/article/recovering-fine-gold-with-oleophilic-adhesion-3041/

I have a subscription and I have read the article several times. No commercial mining operation uses grease tables to recover gold. The article was about a very small scale experiment by one man. I'll take the educational license and provide just a small quote from the article you are linking to.

Another limitation is that gold that has an iron oxide coating or is still encapsulated by quartz or other gangue will not stick to the oil coating. This also happens to be a drawback with mercury amalgamation. For mercury amalgamation and oleophilic adhesion to take place, gold must have a free, clean, open surface to make contact with the mercury to be amalgamated or to adhere to the Vaseline.

Ores rich in sulfides can be a problem as well. The sulfides can quickly adhere, leaving little space for free gold particles. Also, there may be deposits that contain other heavy oleophilic minerals that adhere quickly, taking up the oily space and leaving little space for the gold to be captured.

Using Vaseline to recover gold isn’t necessarily the best method for recovering fine gold from all ores or concentrates, but it does work on many and is worth testing.

Obviously we are talking about minute quantities of gold in both Capt Nemo's experiment and the ICMJ experiment. I'm making an educated guess that neither of those experiments even paid for the materials or the labor involved much less ever produced a profit. Grease tables have been tried in commercial gold recovery operations many times over the last few centuries. The fact that grease tables aren't used for gold recovery but froth flotation is commonly used should be a clue as to the probable end result of trying to make a profit recovering gold with a grease table.

Have you considered burlap and fish oil as a sluice lining? I've heard it can produce many pounds of gold with no effort from places that gold is not commonly found. Or you could ask Tom Massey if you can pan his boots.

Sometimes it may be better to rely on thousands of years of mining experience rather than trying to reinvent the process.



Or not.

Heavy Greasy Pans

 

[johnedoe]

Have you considered burlap and fish oil as a sluice lining?

No but i have heard many parts are edible.......

As to oleophillic adhesion it is true large scale operations don't use it and my guess would be froth floatation has fallen out of favor as well.
But since none of us here are large scale operators it's interesting to experiment occasionally with different techniques.

On the beach I use the Cleangold magnetic sluice , some sawtooth mat, she deep V and some gold hog matting.
I also have and use a gold cube so I am pretty well setup for capturing and keeping the fine gold mostly in the -100 to +150 mesh range, some smaller and some a little bigger occasionally.

I am a beach miner because that is what is the easiest and closest gold available to me... I won't be quitting the day job.

Anyway... heavy pans back at ya...

 

[KevinInColorado]

The majors use froth floatation tanks extensively. For copper, gold, etc. Been there, seen that, enjoyed every bit

 

[johnedoe]

The majors use froth floatation tanks extensively. For copper, gold, etc. Been there, seen that, enjoyed every bit

Good to know...... But way out of my realm of experience...

 

[Goldwasher]

The thing with the ICMJ test and yours.

You are making your sample to be partially recovered...and measuring what wasn't.

In a lab situation. In the field abrasion and random material are going to behave differently. The gold is sinking into the grease because of gravity and density...once that grease isn't sticking to the plate it will go down the sluice with any gold sticking to it.

If you look at the mechanical patents they all scrape and re apply the grease during the run. The grease will be fouled quickly with any kind of production level material introduction.

Go with what your seeing gold goes down and gets stuck in stuff....I prefer that stuff to not be messy attached to gold and adding another step...like separating grease from gold.

 

[Capt Nemo]

Yeah, it is messy, and won't change my main workflow from what I do currently. (sluice/supercon/table) I'd only use this method in final cleanup of tailings. The only other use is to try finding diamonds, and for that, I'm looking mainly for indication of their presence and sampling rather than actual mining.

 

[russau]

Actually I prefer to stay away from diamonds..................they keep getting me into trouble with the females every time!!

 

[goldenmojo]

Yeah, it is messy, and won't change my main workflow from what I do currently. (sluice/supercon/table) I'd only use this method in final cleanup of tailings. The only other use is to try finding diamonds, and for that, I'm looking mainly for indication of their presence and sampling rather than actual mining.

Here is a little background music for when your running the grease table.

 

[Capt Nemo]

Just cleaned the cons from the table....WHAT A PAIN IN THE ASS TO GET THEM FULLY DEGREASED!!!!!

DON'T DO IT!!!! RUN AWAY...RUN FAST!

Started by melting the Vaseline to liquid and pouring off. That wasn't too bad at all.

Next, I tried rubbing alcohol to break up the residues. Didn't do much. Stuck it back in the hot water to remelt the Vaseline and built a Lava Lamp. Poured off as much of the blobs as I could without loosing the ones holding black sand.

Next, I filled the beaker with 20ml of Dawn and the rest with hot water. Have gobs of melted Vaseline floating on a heavy hot solution of Dawn and they still haven't dropped all the black sand yet. Don't know if there's any gold still attached.

If that doesn't do it, I'll put it into a crucible and let it dry, and then burn it off with a Bunsen burner.

This table has a one way ticket to the trash can!

 

[Goldwasher]

Just cleaned the cons from the table....WHAT A PAIN IN THE ASS TO GET THEM FULLY DEGREASED!!!!!

DON'T DO IT!!!! RUN AWAY...RUN FAST!

Started by melting the Vaseline to liquid and pouring off. That wasn't too bad at all.

Next, I tried rubbing alcohol to break up the residues. Didn't do much. Stuck it back in the hot water to remelt the Vaseline and built a Lava Lamp. Poured off as much of the blobs as I could without loosing the ones holding black sand.

Next, I filled the beaker with 20ml of Dawn and the rest with hot water. Have gobs of melted Vaseline floating on a heavy hot solution of Dawn and they still haven't dropped all the black sand yet. Don't know if there's any gold still attached.

If that doesn't do it, I'll put it into a crucible and let it dry, and then burn it off with a Bunsen burner.

This table has a one way ticket to the trash can!

Been trying to tell ya

 

[Assembler]

Just cleaned the cons from the table....WHAT A PAIN IN THE ASS TO GET THEM FULLY DEGREASED!!!!!

DON'T DO IT!!!! RUN AWAY...RUN FAST!

Started by melting the Vaseline to liquid and pouring off. That wasn't too bad at all.

Next, I tried rubbing alcohol to break up the residues. Didn't do much. Stuck it back in the hot water to remelt the Vaseline and built a Lava Lamp. Poured off as much of the blobs as I could without loosing the ones holding black sand.

Next, I filled the beaker with 20ml of Dawn and the rest with hot water. Have gobs of melted Vaseline floating on a heavy hot solution of Dawn and they still haven't dropped all the black sand yet. Don't know if there's any gold still attached.

If that doesn't do it, I'll put it into a crucible and let it dry, and then burn it off with a Bunsen burner.

This table has a one way ticket to the trash can!

Thanks for sharing the story Capt Nemo as this will be a story you will never forget.

 

[Capt Nemo]

Well, here's the good news! Found about twice the number of pieces I thought I caught!

So it does work better than a miller table at catching gold, as it caught quite a bit of what the table dropped......BUT! the mess is not worth the hassel of degreasing, and you STILL need to pan it's tailings! It works, but it's not a magic bullet that some purport.

Here's what the grease caught, and hopefully I didn't loose any to the grease! (Garrett 10" pan)

 

[Jason in Enid]

I would have thought you would use a strong acid or base to dissolve the grease and leave the gold behind. Thanks for sharing the journey with us!

 

[Capt Nemo]

In that sample, it had other metals than just iron, so acid would not be a good idea. Part of it was fine zircon/reidite sand from the Rock Elm disturbance with a SG of 7. Fanning that stuff off the gold is really tricky, as it wants to move less than the iron sand, and the gold tends to be round there, so the zircon hitting it makes it move. I'm also limited in the chemical side of things. I have the apparatus, just not the chemicals to go with. A strong base might soponify the whole mass and make things even worse to recover. Gasoline or toluene, maybe MEK or acetone might work better than alcohol at dissolving the grease, but you will have a fire hazard. I'd rate this as being worse than having to deal with mercury coated gold.

The gold used in this experiment did not get captured by my miller table, so it is very hard stuff to capture. The grease caught a good 60-70% of it. Had I run straight concentrate, the grease would have captured everything that the miller table would have caught plus the 60-70% that it wouldn't catch. So you can't say that it's a totally bad method for recovery. It just takes a lot of screwing around to do it. Any gold under #300 will not be caught by this, and if it is, it's just luck. So fish oil and burlap is BS for micron gold.

Recovery wouldn't be so bad if a simple method of degreasing can be found. With the Vaseline being paraffin, burning it off might be the easiest option.

If you want to have some fun experimenting and getting dirty and finding a new method, HAVE FUN! Otherwise, STAY AWAY until this method can be refined.