Help with bench placers with a lot of clay

[burtonridr]

Hey Everyone, long time lurker here, first post.

I found a location where there is a fair amount of fine gold, by "fine" I'm not sure what I have in terms of classification size, but judging by pictures I've seen, maybe 50 to 100 mesh. The site has a highway between the bench placer and a river, so no way to pump water to the site. I've dug out two buckets worth of material and started worked through it with a small pan in a tub, here is what I've been doing.

Breaking up the clay with my hand, panning out all the light stuff(about 15-20 min). The material I've worked in the past, doesn’t contain clay and so mush black sand, so I can usually work through it faster. But this stuff seems to just take forever and the heavy stuff doesn’t seem to fall to the bottom as easily, it's like I have to work it down a layer at a time. This is the area I would really like to improve and I need help figuring out a way to work through more material. Any suggestions?

Then I've been taking the heavies(lots of black sand) and put them in a soup bowl under a running faucet to further remove material(20-30 min). This part I think I will try building a miller table or something, I think I can cut this time in half.

Then back in the pan before sucking them up into a bottle(10-15min).

This has been working great, I've been getting a great amount of the fine gold in each pan. Problem is the amount of time it takes, and I know I'm losing some of the gold in the process(probably during panning and separating the heavies). I'm only processing 1 pan(small pan) every hour start to finish. I can get 2 pans every 1.5 hours if I don’t watch the black sand in the soup bowl and start a new pan at the same time. I'm looking for ideas to improve the efficiency of my processing a little. My goal is to be able to work through 2 buckets of classified material in a hour or two.

What can I do to remove panning from the process without losing gold or maybe make the process go a little faster? I was hoping to do a recirculating sluice, but I read on here that with the clay it needs a few settling vessels to help keep the water from getting to thick and not allowing the gold to settle out. I don’t know if this is what other have experienced? But, I really don’t want to build the large of a set up to run a few buckets of material. Any thoughts or ideas to look into?

Thanks in advance for the help

 

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[Johnnybravo300]

I see what your saying about the clay. I thought it was a solid layer like around here. There may be no easy way!
Are there better gravel layers on top that can be washed clean easier?
It sure sounds like your spot on with seeing all the rusty red iron dirt.

 

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[burtonridr]

I see what your saying about the clay. I thought it was a solid layer like around here. There may be no easy way!
Are there better gravel layers on top that can be washed clean easier?
It sure sounds like your spot on with seeing all the rusty red iron dirt.

I'm not sure, I will examine the layers a little more the next time I'm out there. Thinking about it, it did seem like most of the clay was a little below the rusty stuff, but im not sure.



Here is the process I've come up with after all the input and further research. I found a post by a guy on here that does a lot of fine gold recovery in washington state, he really likes the vortex mat for the fine gold. The basic theory with this is to remove most of the clay by washing it before running through the recirc to prevent clay build up in the recirc water.

1. Wash material in a wheel barrow to break up and remove the majority of the clay(tried this the other night and it only takes maybe 20 min to wash two buckets)
2. Classify down to 1/4"
3. Classify through a kitchen sieve(don’t know the exact classification size, but seems about right for final panning)
4. Run classified material through a 6"x24" mini recirculating sluice with vortex mat.
5. Pan cons and collect. (The gold hog video on panning tips is priceless, learned a lot with that video highly recommend)

My hope is that by breaking everything up into steps and processing maybe 2 buckets at a time I can be efficient about it. At the moment I've got a few things on order to build the recirc sluice, probably wont be here for another week. I will try to give an update after running some material.

 

[et1955]

I'm not sure, I will examine the layers a little more the next time I'm out there. Thinking about it, it did seem like most of the clay was a little below the rusty stuff, but im not sure.



Here is the process I've come up with after all the input and further research. I found a post by a guy on here that does a lot of fine gold recovery in washington state, he really likes the vortex mat for the fine gold. The basic theory with this is to remove most of the clay by washing it before running through the recirc to prevent clay build up in the recirc water.

1. Wash material in a wheel barrow to break up and remove the majority of the clay(tried this the other night and it only takes maybe 20 min to wash two buckets)
2. Classify down to 1/4"
3. Classify through a kitchen sieve(don’t know the exact classification size, but seems about right for final panning)
4. Run classified material through a 6"x24" mini recirculating sluice with vortex mat.
5. Pan cons and collect. (The gold hog video on panning tips is priceless, learned a lot with that video highly recommend)

My hope is that by breaking everything up into steps and processing maybe 2 buckets at a time I can be efficient about it. At the moment I've got a few things on order to build the recirc sluice, probably wont be here for another week. I will try to give an update after running some material.

Do these pics look like what you are mining. If so I can help you since I have been mining deposits like this for over 25 years on the Sultan river, Wash. Vortex mat not really needed, 1/8" and 1/4" V grove mat works great. Ed

 

[KevinInColorado]

Notes to help you:
1. A typical kitchen sieve is 18 mesh. That's good for panning. For fine gold you'll also want a 40 and a 60 mesh to go with it. Otherwise you'll have a really hard time with the fine gold separation.
2. Vortex mat should be run at a 15 degree angle...much steeper than riffle sluices. This is based on all the testing done by the guys who invented the gold cube.

 

[burtonridr]

Do these pics look like what you are mining. If so I can help you since I have been mining deposits like this for over 25 years on the Sultan river, Wash. Vortex mat not really needed, 1/8" and 1/4" V grove mat works great. Ed

Yep that is very close to what I'm seeing, mine might contain a little more silt and clay though. I ordered the vortex mat since it was cheap, like $10.... I will have to look at the V groove you mentioned. How are you processing the material you are digging? Is it producing mostly fine 50-100 mesh gold?

Notes to help you:
1. A typical kitchen sieve is 18 mesh. That's good for panning. For fine gold you'll also want a 40 and a 60 mesh to go with it. Otherwise you'll have a really hard time with the fine gold separation.
2. Vortex mat should be run at a 15 degree angle...much steeper than riffle sluices. This is based on all the testing done by the guys who invented the gold cube.

Cool I will design the sluice to run at 15 degrees, and check out the flow on the gold cube.

Thanks Kevin, good to know what the kitchen sieve is, up to this point I've been making guesses on particle size, this will help a lot. The metal mesh type right?.

It's funny, I use to be against screening because I thought it was a waste of time. Now, after only being able to pan through about 2 pans per night after work, and still not even through 1 bucket of material, I'm all for classifying. Classifying removes a lot of material quickly and easily, it's going to save a lot of time trying to run a couple buckets in a few hours. I figure I've basically got to the material worked down from 2 buckets to about 2 pans of cons, but I don’t know if that is possible yet. Maybe further classifying will remove a lot of material.

 

[burtonridr]

This is similar to the sieve I'm using,


This is around 18 mesh?

Lol btw my wife loves that I'm involving the kitchen tools in my prospecting efforts

 

[arizau]

The thing about classifying gold concentrates (emphasis on concentrates) to smaller like sizes is that, when you do, the panning becomes much easier. Gold, when like sized with non gold in a pan, is king and it is easily separated/panned from them because it is at least 3 or more times as heavy as particles it's own size. Classifying in approximately half steps say from 18 (20) to 40, then 80 mesh etc., will make your efforts of gold recovery much easier. When you get down to the smaller sizes it is better to pan in small quantities even down to about a tablespoon or less for the minus 80 or whatever.

Good Luck

 

[IMAUDIGGER]

The best gold is usually on top of the clay, not actually inside. Rarely is it worth messing with clay.
Clay is a false bedrock so clean off just the top inch and see what that sample looks like. There's no easy way to deal with clay and it's not usually worth the work for the little amount that will penetrate.

Maybe if you are dredging in a river....In my opinion, geological actions over hundreds of thousands of years can create situations where gold can be found in so many different scenarios that it is impossible to come up with hard and fast rules that apply everywhere. You can come up with some rules of thumb for a particular region and they hold true for the most part. However great finds can be made by thinking outside the box.

Here is a picture of material bound together with clay...not concentrated like brick clay, but locked together tight like a brick.
There is red clay and blue clay.

Takes a trommel or some other aggressive method to break it up.
I would consider building two small lined ponds, and recirculate the water

It doesn't take a very large trommel, nor much water to process as much as one guy can shovel.
I would avoid running gumbo brick mud through any recovery system.

 

[goldenIrishman]

I've used the good old paint stirrer method in the past with good results. Take a half bucket of the material, add water to the top and let it soak for a day or two. The water I add is actually a solution of washing soda. Let it soak for a day or two and hit it with the mixer. The type I use is the kind made for mixing up drywall mud that's chucked up in a 1/2 in variable speed drill. A few minutes with that and I've got a nice slurry that can be run through a recirculating sluice with no problem.

I'd also suggest investing in a full set of classifiers. Not only will they make panning more efficient, they'll also keep you out of the doghouse for using the better half's kitchen gear. (Go ahead...ask me how I know!)

EDIT: Actually which system you choose should be decided on by what the materials call for. It's no different than choosing what gear to work your deposit. Let the terrain dictate what's needed. If you're going to be doing small batches the bucket mixer method may be best. With larger batches you can step up the gear to the cement mixer setup. Scale the tools to the job.

 

[et1955]

Is it possible for you to post pics of the area, I need a better understanding of what you are dealing with, if possible show the river, highway and the bench.

 

[KevinInColorado]

This is similar to the sieve I'm using,
View attachment 1412440

This is around 18 mesh?

Lol btw my wife loves that I'm involving the kitchen tools in my prospecting efforts

Yup, those are usually 18 mesh

 

[burtonridr]

Is it possible for you to post pics of the area, I need a better understanding of what you are dealing with, if possible show the river, highway and the bench.

Lol, I would but it might attract un wanted attention..... Any rock hound in the area would recognize it pretty easily.

I will get a couple of pics of the deposit that wont give away the location and post them up, and something showing the material after classifying it.

 

[et1955]

Just trying to see if you have water source nearby, I and my friends specially mine the benches on the Sultan, the gravel bars were mined out back in the mid 1990's and since the river is controlled by a dam and the SPUD will not let the river ever flood again we found better ground by mining ancient bench deposits. Now our method is to wet classify at the source material to 1/2" and then bring it down to the sluice to run, the gold we find averages 1/8" to 1/2". I should also mention we came up with a homemade classifier for this process. Sadly there is nothing like it on the market. If you want PM me I will send you a pic of what we make.