Confounding Sluice Problem

[omnicron]

Omni if you use the screen as shown @ flat on top of the riffles you will be creating another problem I think. 1.Larger rocks that manage to get thru the screen won't be able to get back out. 2.Your riffles aren't going to work properly because of the turbulence created by the expanded metal. Wes

It's not going to be sitting on top, I'm going to space it about 1/2 to 3/4" off

 

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[chlsbrns]

Chlsbrns, umm I don't even know how to begin to respond to your comments...lets just say you must have no real experience behind a suction nozzle.

If you say so!

The whole reason for larger sizes is to move more material including the larger rocks. To move all the rocks out of the hole by hand would slow you down beyond slow.

It must be easier and waste less time to keep stopping to remove the rocks from the sluice?? I thought that was what you were trying to fix.

Your solution is just assnine, it would be faster to use a gold pan at that point.

Asinine is asking for help and then disputing what is known to work.

Oh and by the way, John has more experience dredging/prospecting they just about anyone on this forum.

Says who you? He obviously didn't offer a solution to your problem so there must not be a solution. He does however think that putting a hose clamp on a nozzle will LOL "ruin" it.

From what I have seen, it's the smaller sized rocks that hang up first the other rocks hang up on them.

In your first post you said the large rocks hang, then you said the small rocks hang and now you say this??

Good luck!

 

[goldhog]

There are several things you can do, but it depends on your tools and ability as well.
Larger rocks will lose energy the further they travel down your sluice.
So, you can build a new frame. Use 3 or 4 riffles, then run only expanded for the rest of your sluice.
Large gold will hold up top, then rest of the fines will hold in the expanded.
However, rocks will not have to deal with riffles further down the sluice.
You'll still have to have a frame all the way down to hold it, and want to use steel not aluminum.
We'll have rocks go down we call POUNDERS because you can wiegh them in pounds.
Doc

 

[Goodyguy]

Omni if you use the screen as shown @ flat on top of the riffles you will be creating another problem I think. 1.Larger rocks that manage to get thru the screen won't be able to get back out. 2.Your riffles aren't going to work properly because of the turbulence created by the expanded metal. Wes

I saw that right off, big no no! Space that punch plate. (but not uphill) material needs to pass between the punch plate and the top of the riffles.

Here is another problem ......take that tray out, (red arrow pointing to it) It's working against you the way the sluice is set up! Also take the expanded out. Un-necessary in the under flow area.

And don't try the expanded over the riffles either, especially with no clearance between it and the top of the riffles. but even with clearance it would just load up with rocks.

I'm confidant John would agree with these suggestions. But get his take on them anyway.
Gold Hogs suggestions would work as well. But the way it's set up now is not effecient.




GG~

 

[omnicron]

OK guys. The top section has between 1/2 - 3/4" spacing from 3/8 punch plate to top of stage 1 riffles. The tray your referring to is just a support for the 3/16 punch plate. I tried running without the support but it caused the undercurrent section to not clean out. It sits 1/4" higher then the riffles on the second stage. I can try the undercurrent section without the expanded and hope the vortex will work solo.

 

[goldgit'r]

Omni,I can't really tell from the pics but it looks as if you have a huge amount of water going to the under current part of the sluice and may be starving the top and that may be causing the problem.Also the welded wire you are using is bad about holding rocks,punch plate seems to work much better for me. Wes

 

[Goodyguy]

You must have a support under the punch plate but not one that blocks the flow under it to the riffles. The smaller lighter material needs to be able to wash down and over the riffles from underneath the punch plate.

Oh and whatever you do, do not put expanded between your riffle tray and mat. It prevents a good seal between riffle and mat causing loss of gold due to migration underneath the riffles.

GG~

 

[Reed Lukens]

Sorry I don't have more time in the summer to help, I'll be back this winter. The HP350 is too small now for that box. Either upgrade to the 400 which would be minimum or the 9hp HP500 which will run it fine and is what I use with a 20ft hose. The added water needed for the undercurrent is more than the HP350 can put out. You can shorten your hose to 12 ft and that will help but I'm not sure if it will be enough to clear the problem. Flat out, you don't have enough water to run a 16" wide over under box now. The lower sluice will catch the gold, the upper is for the nuggets. Your box looks fine as is. The expanded metal is ridiculously large. Size it to the size of nuggets that you might find. If small 1½" rocks are getting stuck then the 2oz nuggets the size of that expanded won't even get started down the sluice. So no expanded over ½" makes much sense most anywhere in the US other than a few places with those large nuggets in abundance.

 

[diggerdoug2]

every dredge or sluice box has a magic number, you have to find the right angle and water speed. the faster the water the flatter the box.the slower the water the more angle you need. you need to find the angle and speed to push the big rocks and be able to save the gold. test you tailings and see what you get. then test and test again. when i got may 2.5 i tested the tailings and the box to see where the gold was at. then i adjusted untill i was saveing as much gold as the dredge would catch.
diggerdoug2

 

[Hoser John]

Sure wish ya was closer as 1 hour in the water with that thang and could have it going like gangsters with a few tools to tweak it here and there. Hands on rocks-internet and a few pics not so...John.

 

[omnicron]

Thanks guys! So I went dredging again this weekend (I love being underwater feeding the fish, I've even named a few lol) And after moving the box up and down from 4" to 1-3/4" in 1/8" moves with different engine speeds after each change and watching the rocks interact with the riffles I have determined that the riffles are the cause of the problem. These riffles are the ones that were on the dredge when I bought it (to lazy to make another set, you get that way after working 45hours a week and then dredging on the weekend for 6 weeks ) What I am seeing is the small flat rocks (1.5") are hitting the riffle but the angle is so steep that they hang up. Some are pulled backwards by the vortex, but the heavy ones stay and then other rocks pile up on it and before you know it I have a rock parking lot!

So maybe I should describe my box config in more detail as it may help incase it's not the angle of the riffle.
My 1st stage is 12" long with 4# grating, this stuff is only 5/8" tall with the long way diamond opening being around 3.5" (this stuff catches fine gold like a tornado in a trailer park LOL ) and then I have 3/8" punch plate over the top of that that ends just past the riffles and it's around 1/2 or so above the top of the riffle.

My under current section consist of vortex matting with 3/4 aluminum raised expanded. The separator plate is 5/8" tall with 20 water dams configured in banks of 3,2,3,2,3,2. This section catches gold and black sand like there is no tomorrow. It has 3/16" punch plate over the opening that is 8-11" variable. I need to fix the opening (tweak it and make it look better.) In all honesty this section is fine, just in the pics it looks like it's deep but that's just the opening.

The over section is the problem child. It has veranda carpet (thanks John for turning everyone on to this amazing carpet) As stated the riffles are not set at a 45 degree angle...more like 75 degrees and they are 1" tall and the spacing between them varies from 3 to 3.5 inches. Again these came with the dredge I just adapted them to work. This section is about 24" long and the riffles have so much vortex that it will pull upto a 1.5" rock against the water flow and gravity. (my bad for not double checking the riffles before I made my op) What I'm considering for this section is some more of that 4# grating but that stuff is so friggin heavy and I'm completely out of it also so I guess I'll bend up for riffles 3/4" tall at a 45 degree pitch for sure this time.

On a side note, I'm losing gold out the rear of the box, the rock that hang up are causing the riffles to clear out. I tested my tailing and each time I had several specs of fine gold in each pan. I cleaned out and processed each section individually and this section had the least amount of gold as it should but after a day of running it should of had more gold then it did.

My best weekend I ever had was 2 weeks ago, I pulled in 5 grams but this weekend so far ('ve only processed Saturdays cons) I'm sitting at 4.5 grams, Sundays cons look awesome. I'm hoping for a total clean out of 7 grams. Might not sound like a lot to some of you big dogs but this gold is all -30 and my box was losing gold.

Thanks everyone the for tips, advice, criticisms and what not

*Fixed the 5.8" to 5/8"

 

[goldhog]

Dealing with larger rocks will always be a concern for you.
You'll eventually get it tuned. Just keep working with it.
Funny... watch the first minute of this video and you'll see some of the "pounders" we send through. lol
By the way... click the little GEAR below the video and change the quality to 720.
Post some pics of your gold too.
Doc

 

[Oakview2]

I agree, show the fruits of all your hard work

 

[Hoser John]

SAY WHAT-your under has 5.8" of height?? Holy cow man that's a HUGE amount of water. Undercurrent should be small height and your 5.8 is more than my whole over/unders total height. Below should be just a few small riffles(8-10 about 1-1 1/4 tall") and good to go. No wonder your saying that fantastic pump isn't enough when MUCH MORE than enough. Frustrating not to be able to run and fix in person. Your top riffle angle--which you say you got to work---but still losing gold--so how can that be working Lookn' fer pics to try to help but NOT livn' at home at the moment,just visit on off days and then just trying to pay bills,wash,fix stuff and back off again-sorry-but ban makes life more complicated here in kalif,land a stupidity-John

 

[Oakview2]

Hoser say your prayers for a fair hearing on the 23rd and just maybe the judge will uncomplicate your life

 

[omnicron]

Sorry John that should of been 5/8" tall and not 5.8" lol.

Here's a pic or two


Wow looking at the pics, I need to go back in and get the BS out I don't know what to do with the electrum either, I had a essay done a week ago and my gold is 86.7% gold and 13.3% silver. If you guys remember a thread a week or two back asking what that crap on my gold is, well it was ore and once I broke it up it yielded electrum.

 

[omnicron]

For your viewing pleasure...My final tally for Saturday and Sunday...I am so frigging happy I don't care that my box is losing gold!!! Well I do actually.

grams

dwt

I forgot to include the .5 grams of +30's
My best clean out ever!!!!!!!!!!!!!!!!!!!!!!!!

 

[Jason in Enid]

If you are catching that, I don't think you are bad at all! Remember, it's a dredge not a pan. EVERYTHING is a trade. I would happily let the 100 mesh stuff flow out if I was catching that.

 

[omnicron]

Your right, I was fortunate to be able to make a day trip today...I tried lower profile riffles on the first 3 riffles. All that did was cause the pile up at the end of the sluice now and I still had a few pile ups after the first few riffles. I think I'm going to make some medium profile riffles and then over lay 3/16ths rod spaced 1/2 to 5/8ths of a inch apart across the sluice, I think it should be ok sitting on top of the riffles. I think this will allow the rocks to pass freely while allowing the riffles to do their job. Anyone have thoughts on this>?

Also I want to hear from some pro's on their take on riffle spacing and design....John...Reed...Doc...Who ever else...

All advice so far is being considered, and I'm also considering gold hog mats but it's so damn expensive...

 

[Jason in Enid]

The easier solution is to move more water, increase the box angle slightly, or both. If you keep hacking at your sluice, you may not be able to catch anything in the future.