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Sluice slick-plate?


Randall

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After much reading I have concluded there must be a million ways to configure a sluice :idunno: What my question is...if you pre-classify material to quarter inch and place in sluice wet could it be placed directly on vortex matting instead of a slick-plate area? If no...what length of slick-plate area would you recommend for an overall sluice length of 36" x 10" width? 

Just to share something else I came across regarding sluice box design (I never knew) is using a flare which some say creates the "V" fallacy? Channels the water flow not really evenly across the sluice which creates build-up of heavies unevenly? Maybe I'm just splitting hairs so I came here for guidance from those with sluice-box experience :worship: 

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I like to visually monitor my sluice.  I like to be able to see the gold in terms of size and shape.  Thus, in my metal sluices, I install "V" matting (rubber or plastic non-slip footing material) in a portion of the flare and the entryway of the sluice proper.  Some of the gold readily hangs up in this zone.  It enables me to study the water action over time (i.e., whether the sluice is or is not gradually tilting out of line or whether upstream factors are gradually changing the angle of flow patterns).  In my plastic sluices (mostly Angus MacKirk models for the smaller ones and some Le Traps for the larger ones) I just leave them alone because they work so well without all the complications that metal sluices present.  These are generalizations on my part.  But I encourage you to experiment as much as you want with specific applications.  After all, fooling around and tinkering with better ways to capture gold is an important source of satisfaction for many of us.

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As far as pre classifying, the smaller you get, the more time it takes. 

Also, I'd get whatever Keene Sluice you want, and if you don't like it, you can tweak it with different style mattings for whatever works best for you and your area.  The mattings are not terribly expensive.  I have a Keene sluice with riffles, expanded metal, and carpet.  I've changed the carpet that came with the Keene to ribbed rubber matting and even ran that without the Riffles.  I also went to the ribbed matting only.  The ribbed matting by itself was good for some sands that I had.  If the material is glued to the surface of the sluice, it can still come off and your matting of choice be put down.

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On 10/3/2018 at 1:50 PM, Randall said:

...What my question is...if you pre-classify material to quarter inch and place in sluice wet could it be placed directly on vortex matting instead of a slick-plate area?...

Notice all the dancing around your question? You will never get another to give a "yes" or "no" reply to what is asked due to the way it is asked.

The actual answer based on sentence construction is: It's your material; you could do with it anything you want.

If it was my material though it would first traverse slick plate prior to a matting encounter.

If someone else is feeling wordy and wouldn't mind explaining (typing / copying n pasting) the physics and other reasonings pro-and-con behind both approaches, I humbly yield the floor...

Swamp

** PS: Hmmmm, not exactly what I envisioned as a first comment following an entirely-too-long absence.. But then again, given what's been going on with me as of late, this fits neatly within the realm of all probable and a few improbable possibilities..

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6 minutes ago, Swampstomper Al said:

Notice all the dancing around your question? You will never get another to give a "yes" or "no" reply to what is asked due to the way it is asked.

The actual answer based on sentence construction is: It's your material; you could do with it anything you want.

If it was my material though it would first traverse slick plate prior to a matting encounter.

If someone else is feeling wordy and wouldn't mind explaining (typing / copying n pasting) the physics and other reasonings pro-and-con behind both approaches, I humbly yield the floor...

Swamp

** PS: Hmmmm, not exactly what I envisioned as a first comment following an entirely-too-long absence.. But then again, given what's been going on with me as of late, this fits neatly within the realm of all probable and a few improbable possibilities..

Welcome back Swamp !!  :thumbsupanim

Hopefully this message finds you well, or at least better than before.  I'm sure many of us (more than just myself)  had wondered about your absence. :)

 

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I have slick plate even if classified down. Gives it a better chance to break up and the gold to fall out. Thats just me though.

WTH??? Did i see a post from Swamp??? Welcome back buddy. Glad to hear you are back with us.

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1 hour ago, nugget108 said:

I have slick plate even if classified down. Gives it a better chance to break up and the gold to fall out. Thats just me though.

This is it in a nut shell.. I too want the Au being caught at the very beginning of the matting rather than that location being used as a starting point for ensuing separation..

Howdy howdy LukeJ, nugget et.al.. Not wanting to hijack the thread.. I'll post something in the Lounge before too very long.. Have a lot of catching up to do here myself..

Swamp

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On 10/3/2018 at 1:50 PM, Randall said:

...what length of slick-plate area would you recommend for an overall sluice length of 36" x 10" width? 

Just to share something else I came across regarding sluice box design (I never knew) is using a flare which some say creates the "V" fallacy? Channels the water flow not really evenly across the sluice which creates build-up of heavies unevenly? Maybe I'm just splitting hairs so I came here for guidance from those with sluice-box experience :worship: 

Ok, I'll get serious here for a minute ( OH NOOOO, MR. BILL ) :yikes:

I'd recommend a 12" length flair design, with anywhere from 0" up to approx. 2" of slightly < to = 10"w 'tongue', depending on how you plan on fastening to the 10"x36".. This is/was pretty much the "old skool" industry standard EZ-carry length for a riffle and/or expanded metal + miner moss and/or substitute/addition setup back in the not-so-distant day..

With the onset of today's "super got'cha" mattings and/or improved riffle and expanded metal designs you can now find production-run sluices down to 24" in length or homemade doers even shorter, but they all will still have an approx. 12"L leading slick plate.. There are very good reasons for this lead with typical gravels/sands/dirt materials (as earlier noted) beyond its being an aesthetically pleasing design element (gold-bearing clays are a whole other story however..) And none of this even begins to take into consideration any of the most excellent recovery newer plastic and composite-materials sluices that've been hitting the marketplace the last decade or two.. Choices abound..!

I've never heard of the V fallacy either I don't believe, or if I have I've ignored it and/or dismissed it -- since it makes little-to-no sense other than to those pulling the profit.. For starters, prior to $33.95 (or $23.95 or $28.95) "sluice levelers" being "invented" that V was and still is all one needs to do a sluice's proper per foot length drop, side-to-side leveling at the feed end and water-flow adjustments, with the latter also at least partially tying back into the drop factor adjustment.. One doesn't need a bubble or digital level to lose in a stream, or have to break in your back pack / pocket -- or need to use in order to properly set up a sluice.. All one needs is flowing water and a halfway-decent eye..

Build up of heavies..? LOL ! ! Me me me me meeeeee please..! Where at? Where they buildin' up in the sluice?? "They're" probably sayin' where the V comes together I bet'cha, which would definitely make the list of Top Fifteen Dumbest Things Ever Said About Sluicing..
Heavies don't ride the V intersect streams; the lights do.. Heavies pretty much slide straight down a skid plate from point of first contact, which is why ya see small gold bits strung out all the way across edge-to-edge in the valleys of the old shallow rolling "u" lead matting used in recent days of yore.. :89: The Au didn't end up strung all the way across because it was colliding in the center then being pushed sideways in the valleys, it got that way by dropping straight down the skid plate and staying put.. I can only dream of locations where the Au is both small enough and voluminous enough that it needs to push its brethern sideways in order to find a spot to settle in matting, cos I've never come across anything like that IRL -- so far.. :miner:

Swamp

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When you say slick plate, is that a punch plate on top of the sluice to help classify? Didn't think that's work real well on a river sluice.  Thought it needed controlled water flow.  I wanted to add that to my sluice, but never did.

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13 minutes ago, chrisski said:

When you say slick plate, is that a punch plate on top of the sluice to help classify? Didn't think that's work real well on a river sluice.  Thought it needed controlled water flow.  I wanted to add that to my sluice, but never did.

Its the first foot of suice with nothing on it. Thats where the material lands first, then breaks up before any punch plate or riffles. It just hits the sluice first.

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Copy.  Mine is covered with Ribbed Rubber matting.  Before that, I do have an attachment to funnel the water into the sluice.  In Phoenix, we rarely have water, and our Aqua Fria River, I diverted the entire flow of the river into the sluice and with the funnel, it had enough water.  The correct terminology probably isn't funnel.

Edited by chrisski
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My main reason for opening this thread was to gain a little more insight on the importance of slick-plates from the more experienced... and ya'lls response is much appreciated! Seems the general consensus say go with slick-plate regardless of whether you classify or not. Initially I was thinking about using vortex matting with no slick-plate feeding into miners moss under expanded metal for remainder of sluice without riffles. My thinking was since material was pre-classified (agitated) maybe slick plate could be eliminated to make room for more gold grabbing space? 

As for the "V" Fallacy.....I came across an article on the internet which included a short topic on the use of sluice flares. Flares can unevenly distribute material?...this is compounded further when one just dumps material in center of sluice feed instead of fanning material evenly across sluice feed. At times I can get confused but God I love this hobby :)

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I don't use the sluice a lot in central AZ, but the last time I brought my sluice to the San Gabriel RIver, that is exactly what happened.  The flare focused the material to the center of the sluice.  It probably V'd in the first third, but then evened out more towards the bottom.  More locally, the recirculating system I have I do not use it and the material is more evenly distributed.

A lot of the flare really depends on the flow of the river.  The few places I used my sluice required the flare just to get enough water moving to pour material over.  Out East, we'd call a lot of the rivers in Arizona brooks.

So, if the water flow allows the use of no flare, then I would go without the flare.  Sometimes there's no choice.

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When using a stream sluice with or without a flair it is important to initially set the sluice such that the inflowing water current is inline with the length of the sluice as much as possible.  Setting a stream sluice at a cross angle to the direction of the incoming water results in an uneven turbulence that will ultimately blow out the finer gold.

With a power sluice this, of course, is not such a problem and can be adjusted more easily than a stream sluice.  In my recirculator sluice set up I direct my two water jet inlets (one on each side of the sluice approximately 5 or 6 inches from the rear wall) upslope such that each of their streams converge at the center of the back wall.  Then I feed my material into these upslope currents.  Not overloading the sluice while feeding it is, of course, very important.  The result is that the clays and pebbles first are initially busted up across the slick plate as they are fed into the upslope currents, then they crash into the rear wall causing clay lumps to further fragment in the churn, then everything gets further disseminated as the mass of material is deflected and carried back down slope from the rear wall of the power sluice.  This downslope material quickly begins to evenly disperse across the width of the sluiceway and the water flow settles into a nice, even downslope rush.

I agree that one should try to leave a reasonable percentage of the sluice bottom as a slick surface to enable as much stratified separation and evenness of flow as possible before it hits the ribbed matting or the riffles.  I use little copper nuggets that I hammered flat from little snips of differing gauges of copper wire to test the flow of my sluice before I begin adding any material to the sluice.  I typically drop either 5 or 10 individual copper "nuggets" into the flare.  Then I count how many are caught by the first riffle, the second and so forth.  Since copper is roughly one-half the specific gravity of (pure) gold, then if I'm catching the large percentage of the copper test nuggets in the first or second riffle I feel satisfied with the angle of my sluice-set and confident that the higher specific gravity gold particles will not be lost.

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