Properly tuned sluice

[No gold in NY]

When I run my Keene A-52 sluice, I see sands and garnet migrating upstream between the riffles. Is this a good thing?

 

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[Eu_citzen]

If the material is "dancing" behind the riffles, then you're doing good.

 

[deserdog]

Its funny that you have the word tune in this thread. Most of my sluices, when set up right, do what I call sing. You can hear the little pebbles hitting the riffles as they go by. And you can see the black sand dancing behind the riffles.

 

[nh.nugget]

I have an A52 when mine is tuned the V of water in the front comes down to the center screw in the flair. When I set up there usually is about an inch or so of water at the front and it's comes up to the rivets on the other end. Runs great!

 

[Laz7777]

"tuning" is relative to the speed of your stream.
in seeing NH's pic, I see the low water conditions he has to work with.
my A52 gets set flat most of the time, with water running to about 1/2" below the top and fast water.
the V on my box is always centered on the second riffle.
that being said, I've checked my tailings and have found next to no gold being lost. most gold I get falls out either on the matting and the first and third riffles. the second riffle with the V of water running over it has too much turbulence and catches just a little. riffles 4-7 get just a little flour and most of the black sand.
if you're running correctly (on most standard type sluices) you should see material scooting backward as it goes over the riffles. there should be a backflow created by the riffles, or else you don't have your box properly set.
you said you're seeing garnets migrating (upstream?)..should be down, right? garnets are heavies and though I see them occasionally, they should be caught by your box. the few I get fall out in the first four riffles, sometimes I need to clear them manually from the matting if I'm running under slightly slower than normal conditions.
maybe you need less angle or you need to run slower.
have you rerun your tailings?

 

[nh.nugget]

The way mine runs I catch most of the gold in the rubber mat and the first riffle. Very rarely anything goes past the third one.

 

[No gold in NY]

Thanks for all the input guys. maybe I'll have better luck this season.

Richard

 

[spaghettigold]

mine is a gravity sluice set up but if you skip to 2.05min you can see the saltating going on,at 2.20 on the left portion of vid you can see some pebbles migrating towards the camera but as soon as they hit the vortex they bounce back under the riffle.

 

[goldog]

Heavies dancing (upstream is good). Garnets falling out of the flow and tucking up under the riffles is just what you want.

I like to run my sluice deep and medium fast. Expanded metal classifier works well. That is when I run a sluice. The bazooka is a different story.

 

[mike(swWash)]

One word answer.... YES!

 

[Lanny in AB]

In my area, what I watch for to know things are going properly are for pieces of ironstone (magnetite), and cubes of pyrite (lots of them as well) to shimmy back up-current to the riffles as garnets are not common at all where I'm currently working.

Learning to adjust a sluice properly depends on several variables (material size, specific gravity of your heavies, volume of material, flow, presence of clay, etc.), but I'd suggest you work in an area where you know there's already heavies (lots of black sand, garnets, pyrite, magnetite chunks, etc. and just play around without worrying about the gold until you see things working properly in the sluice due to slope, water flow, classification of material, etc., then run some pay-dirt and you'll have a better chance at recovery when you test your tailings.

So, yes, when your heavy materials are migrating up, that's good, but there's the other variables you'll want to pay attention to as well, so when you know you're into the gold, you'll need to frequently check your tailings to make sure you're not blowing the gold out as that's the true test to see if things really are working as well as you think they are.

All the best,

Lanny

 

[johnedoe]

This may be interesting to you ......

 

[russau]

While I like the raised expanded use to stuff off the bigger rocks , Im thinking this would disrupt the mats ability to create some of the needed action to capture the really fine gold. Yes I saw the very small particle of gold Doc captured BUT what about the off fall from the sluice ? I have 2 dredges with Gold Hog mat and have yet to get them out to try. Hopefully this year my ole body will let me OR itll be time to toss the towel in for me!

 

[johnedoe]

Those were some of my first thoughts as well.
Kind of a step backwards in using the mats that are designed to perform without expanded....

 

[Goldwasher]

I know of a sand and gravel plant they use expanded over UR as one of their recovery points. It's catches a lot of fines. I think the owner does it to make the matts last longer.

They still run a jig on the sand. To get all that they can.

The feed volume is huge.

 

[Vance in AK]

View attachment 1418683 View attachment 1418685 I have an A52 when mine is tuned the V of water in the front comes down to the center screw in the flair. When I set up there usually is about an inch or so of water at the front and it's comes up to the rivets on the other end. Runs great!

Nhnugget, is that a dredge/highbanker riffle tray in your sluice? If so have you tried it with the stream sluice riffle in those low water conditions? No disrespect intended toward what works for you...

 

[nh.nugget]

It's just a bone stock A52as far as I know it is a stream sluice the riffles aren't very tall. Unfortunately our gold is mostly very fine if you run it fast you will blow gold. I've tried running it about every way possible and that's the best.

 

[utah mason]

It's just a bone stock A52as far as I know it is a stream sluice the riffles aren't very tall. Unfortunately our gold is mostly very fine if you run it fast you will blow gold. I've tried running it about every way possible and that's the best.

I would suggest cutting out most of the Hungarian riffles. Leave the first one or two for nuggets and maybe the last one. For fine gold you need the water to be smooth so the gold will drop. All those riffles will keep the water to violent for the gold to drop out. I did it with my A-51 and it helped tremendously, along with replacing the stock carpet with hog moss and some
V-matting under that.

 

[N-Lionberger]

I have a few A52 sluices and they all have the stream riffle ladders of which none have the same combination of lazy L and lazy Z riffles. I saw in a youtube video Dave Mak using a dredge that on the lower box had only expanded metal over V rib mat, I gave it a try and it seems to work pretty good.

 

[AMP_kbell]

Try running some straight vortex mat (no riffles or expanded metal) - With quarter classification and flows to match you'll be very satisfied.