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Peter Freedman

Jig Or Centrifuge For Flour Gold Project?

16 posts in this topic

Hello All, 

 

I am working out the details for 40 yard an hour washplant for my gold project here in Colorado. I am going to be dismantling old workings of past producing gold mines, The gold is very fine with very little clays, yet some black sands. I can capture the gold from my sample pits well enough in my Gold Cube; sluice not as well. 

 

Looking to price out and piece together the plant; its seems a jig or a centrifuge would work best to capture the fine gold with gravity. 

Does anyone have experience with both techniques and could provide insight?

 

 

 

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Peter,

   A good jig can pull out some pretty fine gold.  I have limited exposure to centrifuges but a guy I worked for in Alaska who was a pretty savvy miner, junked his centrifuges for a jig for first stage cleanup...panning being the final cleanup.

BTW, I am here in Colorado.  Where are you?

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Thanks flint and Chris,

Found this excellent article on gravity separation.

http://www.gekkos.com/documents/025MaximizingGravityRecoveryThroughTheApplicationOfMultipleGravityDevices.pdf

Check out page 12 for a comparison of the method. According to this document sluices and jigs are equall in their fine gold recovery. However, the Kelsey jig, Mosley and centrifuges seem to have the ability to collect smaller pieces.

I am curious to hear from someone that has piratical experience on both the jig and centrifuge.

Flint, I am up in Eagle county....

Ronald C likes this

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Here's some pictures of a jig setup I saw in Alaska.

 

This is the main roughing jig. Its about 8 feet diameter.

jig4.gif

 

Closer look with no running water.

 

jig5.gif

 

 

The slots are about 1/8" x 1" or so.

 

jig6.gif

 

Finishing jigs. 2 total.

 

jig7.gif

 

Gold from about an 8 hour run.

 

jig8.gif

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Outflow from finishing jigs.

 

jij10.gif

 

Test sample.

 

jij11.gif

 

Results.

Looks like a lot but the time spent getting it would produde a lot more of the coarser stuff. You can see a cleanup video at

 

http://golddredgervideo.com/alaska2008/cleanupmusicvideo.wmv

 

 

jij12.gif

 

One big advantage that I saw for jigs was cleanup time. At this site he cleaned up every day and it took less than 30 minutes.

 

Leonard

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Peter - you need to take a closer look at that chart.

The chart is not of the size of the gold recovered, but the feed size. - so you must screen the feed to the bowl to around 1 mm or so certainly much less than 1/4 of an inch. Its a lot of work to produce a split of your placer plant that is that small. Jigs on the other hand take a much larger size feed - say 1/2 inch minus. Jigs are most commonly used with placer plants because producing a 1/2 inch minus is no big deal, and the 1/2 inch plus goes to a nugget trap. If you go through the work to produce a separate 1/25th of an inch feed line, you will still need a jig or something to recover the larger bowl feed and smaller than nugget trap size.

Jigs are much superior to sluices - hands down. The installation of jigs on California bucket line dredges revolutionized that industry because of increased recovery. Bowls are most commonly used in hard rock processing, as you already have crushed all the ore down to the necessary small size, so no problem to deal with the small feed size required. In that application, the bowls remove coarser gold that would take a long time to dissolve by cyanide. That way only the tiny gold particles remain that are more quickly dissolved in the cyanide. I cant think of anyone using a bowl in a standard placer wash plant off the top of my head, and lots of placer plants use jigs.

Finally, the paper saying how great bowls are is prepared by Gekko systems, maker of the Gekko centrifuge spinner bowl. I always take papers by a manufacturer saying our product is better than the competition with a grain of salt.

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Peter,

  What exactly do you mean by "very fine" gold. Is it all -40, -100,  smaller ??

Is this operation going to be a one-man show or multiple workers?

 

 My opinion would depend on answers to those questions.

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Peter,

 

Going back to High School Geometry... The area of a right triangle is 1/2 times the base times the height.

 

A tailing pile (dump) is a little more complicated.

 

To be continued... :)

 

- Geowizard

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