Clean up!

[Geowizard]

Clean up;

The Clean up process is certainly worthy of discussion!

I hope that other prospectors will chime in and share ideas and solutions to the various methods of Cleaning up their concentrates to get that nice, shiny yellow metal.

I personally believe that when a clean up is NOT done properly, much of that hard-earned GOLD goes back where it came from!

- Geowizard

[Geowizard]

Particle size and mesh;

To begin with, clean up involves screening the concentrate into incrementally smaller sizes.

Screens are classified by "mesh" as shown in this reference:

https://www.sigmaaldrich.com/chemistry/ ... rsion.html

- Geowizard

[Geowizard]

Classification;

Successful classification of concentrates is based on the choice of screens used in the clean up.

When concentrates are brought to the clean up room, the first screen is FOUR mesh.

Particles that do not pass the four mesh screen are visually scanned for nuggets. Nuggets are removed and the remaining particles are discarded.

Particles that pass through the four mesh screen are screened by an EIGHT mesh screen.

Particles that do not pass the eight mesh screen are called "four to eight mesh". This size is easy to pan and the GOLD is recovered.

Particles that pass through the eight mesh are screened by a SIXTEEN mesh screen.

Particles that do not pass through the sixteen mesh screen are called "eight to sixteen mesh". This size is relatively easy to pan and the GOLD is recovered.

Particles that pass through the sixteen mesh screen include GOLD that is difficult for most GOLD panners to recover. GOLD this small goes to a "Fine GOLD" recovery process.

Stay tuned!

- Geowizard

[Geowizard]

Weight of 16 mesh;

For reference, here is a link to a table I made of weights of GOLD and SAND SPHERES at various MESH sizes:

http://www.alaska-gold.com/weight_of_spheres.pdf

- Geowizard

[Geowizard]

Ratio of the masses;

Note in the reference above, 16 mesh GOLD spheres weigh almost the same as 8 mesh SAND spheres.

The MASS of both spheres is EQUAL. The force of gravity is EQUAL. It is impossible to use GRAVITY separation to separate 16 mesh GOLD from 8 mesh SAND.

Questions?

- Geowizard

[Geowizard]

Physics 101;

Force = Mass x Acceleration... In a vacuum, there is no opposition to gravitational force. In a liquid, like, water, opposition to the force of gravity is produced by the cross-sectional area of the spheres pressing against water.

The density of water affects the efficiency of panning because larger particles have greater cross-section and are pushed or alternately stopped by the opposing force of water. This is demonstrated by GOLD panning where larger particles having similar mass are "walked" out of the pan by horizontal shifting of the pan!

NOTE ALSO... The "effective mass" of GOLD and SAND is less in water because they are somewhat buoyant! The mass of GOLD and SAND are reduced by the displacement of the mass of water = 1 gram per cubic centimeter.

These factors may seem trivial but need to be considered.

- Geowizard

[Micropedes1]

Back when I was dredging on a regular basis, I believed that the clean up technique needed to be geared exclusively to the size gold that was showing in your dredge. Nuggets on the mat at the top, up to 20-30 mesh behind the Hungarians, and some fine gold in the undercurrent or low pressure area. Concentrates came out of the dredge pretty much prescreened, but we would screen again and separate into less than 8 mesh, 8-20 mesh, 20-50 mesh, and flysh$$t. A quick panning would catch the 8 mesh and larger. Mid sized gold would be run one cut at a time thru a LeTrap and then likely panned too. The tiny stuff went into a blue bowl just to reduct the volume to manageable quantities, then sucked up for later finishing. Most of this occurred out on the river, rarely catching more than a few ounces. Did we lose gold? Undoubtedly! But we didn't care, we caught enough to keep us happy.

Dredging on the 40 Mile was a different kind of recovery. No Hungarians. Everybody ran expanded over miner's moss with a few standard riffles down at the very end (just in case of that elusive nugget). The gold was tiny. We tried the same clean up strategies that we had used on larger gold, with some success. But we also lost gold. Sometimes more than we brought home. It finally got to the point where we would bring all the concentrates back to town at the end of a work week and run them, one classified cut at a time, over some type of bump table (I have a Gemini now that I really like). The really small stuff that came off of the table would go into a centrifuge.

What do I use now? I usually stay with the table and centrifuge. They really work well. But they are not mobile. So, the question remains...just how much of your concentrates can you afford to bring home to process at your leisure? I still have 55 gallon barrels of black sand that have only been run once across the table. I was thinking of setting up a gravity column and running it all thru there one last time before pouring it in the driveway. Or maybe a leach pad with dimethylgloxime.

[Micropedes1]

Whoops, wrong precipitant. Thought I would leach with the HCl and peroxide that we were talking about earlier. Then use butyl diglyme as it is selective for gold in a gold chloride solution..

[Johnedoe]

Here's a little video of a cleanup I helped a friend with.

This was from about 2 gallons of beach concentrates from a couple months of part time digging.

I added Deep V mat to the slick plate of a Gold Cube... Figured why waste a potential working surface that was not being utilized.

The depth of the deep V is about 1/8 inch... They were full and the second mat had a good show as well.
All the concentrates were 8 mesh and smaller.

Enjoy the vid.

https://youtu.be/qs1D6OfvD48

[Geowizard]

ProspectingAK asked;

One thing that was mentioned was cleanup. I have found flakes and I did my best to clean em up. I have no real experience doing any cleanups and was curious where a good place to start would be? Magnets, blue bowls, spiral wheels ...................
need some advice on where to spend my money and get setup well the first time...!!