diamond panning and mining

[flintgreasewood]

As if I didn't already have enough to do with my gold mining interests, now I find myself faced with the opportunity to prospect for diamonds on the Colorado/Wyoming border. I've been learning a bit about the "how to" of diamond hunting but I'd appreciate any advice from those of you who have actually prospected for them. I know the specific gravity of diamond is about 3.5 and quartz is about 2.5 so diamonds will tend to settle to bedrock in a stream situation. Also, it seems like panning for them shouldn't be all that difficult if you know what you are looking for. What I really would like to know is how are they separated out in a suicing setup with lots of yards of gravel being processed.

[overtheedge]

Supposedly they used grease tables; a sluice with a coating of grease that diamonds have an affinity for. They scrape the grease off, drop it in hot water and the diamonds fall out. Skim off the cooled grease and reapply to the tables as needed.

Something I read somewhere so it may or not be correct.

[tvanwho]

I have pics of the African miners and their grease tables. Sometimes it was a proprietary custom made grease.Others have told me its a combo of beeswax and vaseline melted together. You don't want this stuff in your sluice as it will cause gold issues, like putting oil in there, the gold would float off. I tried a short 6 inch section of riffles at the end of my dredge sluice years ago with a layer of white lithium grease. It caught a number of pebbles but none were diamonds. My friend Chuck has got 2 diamonds now from dredge concentrates. Both were like pinhead size. One was a red stone, perfect double pyramid. The other was more like a blue/white crystal. I guess Chuck had nothing better to do than look at tiny bits of gravel.My eyes cannot focus on small stuff anymore.You can go get yourself an LED blacklight flashlight on Ebay.Some diamonds will fluoresce, maybe 1 in 10 might turn orange or blue under UV light. Bad thing is ,a lot of pebbles will turn orange under UV light I noticed. Old time gold miners in Indiana sometimes got diamonds in with the gold at the bottom of the pan. They'd be easy to wash out tho with a SG of around 4 vs gold at 19.

-Tom

[AceHand]

tvanwho, Can you get a pic or 2 on here for us to see? The Canadian Prospectors Forum had a couple threads about it that explain a lot. I googled "diamond grease table sluice" and it was the first response. Colo/Wyo border is further than I usually go from here, but someday I'll make the trip for the gold and kimberlite pipes in the area.
Tom

[utj49er]

Hi, I have a placer gold claim on Hayfork creek in Calif. There have been some nice Diamonds recovered on this creek. I thought maybe there might be some on my claim so I tried to alter my 5 inch dredge to see if I could pick any up.I took the carpet out of the last few riffles of my box.Somewhere I found a good recipe for the grease coating,60% parafin,40% beeswax.Melt this and then coat it on thick in the bottom of your box.Then proceed to dredge.Well this really didn't work to good. When dredging the crap like leaves etc tended to stick to the grease,larger rock tended to scrape wipe out the grease layer,cold water tended to harden the stuff so nothing would stick anyway. So this was a messy pain in the ass bust. What did work was when I lowered the incline on my box carefully keeping an eye on it to avoid overloading it. Then cleaning it ,at the end of the day ending up with a couple of times the concentrate that I normally would have. Then at home in my warm garage I made a plywood box that would fit below my LeTrap sluice box.Then I ran all my cons through that,making sure to keep wet at all times. This captured all my fine gold in the sluice and lo and behold Diamonds in the lower grease trap. Not the Crown Jewels that I was hoping for but some really nice little Diamonds. Now anytime I dredge this claim I save all my fines and run them like this. I have yet to find a large Diamond but just like the picker gold I pick out of my sluice box,I reason that if there are alot of tiny ones there must be a big one hiding somewhere nearby. Hope this helps. Joe

[flintgreasewood]

Good information! I'll look more into the "grease" thing. I did just notice an advertisement for Goldfield Jigs which say they are good for diamond recovery. Does anyone have any knowledge about that method? Like does the jig incorporate a special "ragging" that has a lower specific gravity than diamond?...maybe around 3. If you were using standard steel or cassiterite ragging you would think that the diamonds couldn't penetrate down though it.

[tvanwho]

We met with a guy in central Indiana.His name is Dan Pohle of DiamondDredges.com He builds diamond mining machines for export to South America and Africa. His smallest is a $35,000 dollar dredge with a monster sluice like 10 foot long x 3 foot wide and 6 inch sides fed by 2 separate 8 inch dredge hoses. Yes, you can walk around on the dredge float.It is powered by a small diesel engine. He was very secretive about showing us diamonds he has got in Indiana with another machine that he fed with a front end loader. You can go visit his website and /or look for OtterCreek Trading.com which he goes by as well. I've emailed him a few times since but never get any reply.
I'll see if can post pics of Chucks 2 small diamonds. I just got a new pc and dunno if I got all my photos transferred off the old one, but will check. Need to see how to post pics on this forum too? Do I need to post them over at Photobucket 1st?

-Tom

Good information! I'll look more into the "grease" thing. I did just notice an advertisement for Goldfield Jigs which say they are good for diamond recovery. Does anyone have any knowledge about that method? Like does the jig incorporate a special "ragging" that has a lower specific gravity than diamond?...maybe around 3. If you were using standard steel or cassiterite ragging you would think that the diamonds couldn't penetrate down though it.

[Barney 11]

About 2 or three years ago--maybe longer- the U of Minnesota along with some companies out of Ontairio were going to do a diamond search, study about the prospect of finding diamonds in the blue clay that is suposed to exist along the eastern border of Minnesota. The study was supposed to take a year or better but no results were going to be released until the sudy was done. Just wondering if anyone has heard about this studies results or any information about this whole thing. Just a shot in the the dark question. Don

[Zooka]

Jigs or other fluid bed setups really do well at gemstone collecting, whether it is sapphires, garnets or diamonds, they will keep material by specific gravity. In fact, I have seen big rocks of low SG float right across fluid beds that when the water was draqined from contained "strata" of material mostly by SG. Gold on the spraybar, then magnetite (larger) then garnets. That spraybar was set at about 7 PSI, and around 4 to 5 inches deep. Material screened to 3/4 by the trommel. The sub-50 mesh gold recovery was not perfect but that was what we had the 6 lb expanded grating below for.
A simple fluid bed or better yet a Keene Hydromatic Jig 9which was really just a fluid bed with a reciprocator) is an excellent gem getter.
-Z

[tvanwho]

Sounds rather expensive? How much would a rig like that run us? Got any photos?

-Tom

Jigs or other fluid bed setups really do well at gemstone collecting, whether it is sapphires, garnets or diamonds, they will keep material by specific gravity. In fact, I have seen big rocks of low SG float right across fluid beds that when the water was draqined from contained "strata" of material mostly by SG. Gold on the spraybar, then magnetite (larger) then garnets. That spraybar was set at about 7 PSI, and around 4 to 5 inches deep. Material screened to 3/4 by the trommel. The sub-50 mesh gold recovery was not perfect but that was what we had the 6 lb expanded grating below for.
A simple fluid bed or better yet a Keene Hydromatic Jig 9which was really just a fluid bed with a reciprocator) is an excellent gem getter.
-Z