Confounding Sluice Problem

[omnicron]

Ok guys, so being frustrated with a simple over/under dredge sluice box I built another with a "high grade" section, like the keene 3 stage. I want to be able to check values without doing a complete clean out. To start off, I adjust the engine speed to about 2/3 throttle then adjust the angle to the point that my riffles are not running clean or packing up. The problem lies that the larger rocks, 1.5" and above wont clear off the sluice. I mean they do but while dredging after 5 minutes I need to go up and clear off the rocks otherwise I'll have a big pile. I've tried changing the flare angle, sluice angle and engine speed. It's only when running wide open that the rocks clear off or when the angle is steep (riffles running clean) that the rocks clear.

My riffles are 3/4" tall angled @ 45 degrees, the under sluice section is 5/8" tall, the water level above the riffles at 2/3 throttle is around 2.5 - 3". I'm considering building a grizzly type of screen to set on the riffles spaced at 3/4" apart so the rocks will move easier but I fear that that's just inviting rock jams. The other idea was to use some flat expanded...say 3/4" with the long way diamond toward the head and foot of the box. Anyone have any thoughts?

Btw my pump is an Proline HP350. Anyone have the specs on that pump?

 

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[chlsbrns]

Did you try restricting the size of what will fit thru the nozzle?

 

[Hoser John]

HAHAHAHA never ever do such a bonehead move to ruin a prtfectly good nozzle. O told ya a dozen times KISS-keep it simple man as ifn' ya can't seem to get a simple o/u to work how in the name a LL are you a gonna get a much more worthless convaluted 3 way to work?? Please just stand back and think for a minute?John

 

[omnicron]

Why would I do that! I would be taking a 4" dredge down to 2 1/2 or something. I would then slow down production moving rocks and more rocks instead of just sucking them up. Besides I'm not having plug ups... just rocks piling up on my sluice.

 

[okbasspro]

I see you got a proline pump is the rest proline?

 

[omnicron]

John, I had no problem with the o/u box I built. It was working great...I was catching super fine gold and chunky stuff. Didn't have issue with rock pile ups either... The only thing I hated about it was the fact that when i would move the dredge forward I could not do a quick check of values unless I did a clean out..

 

[omnicron]

Well I'm finding out that this dredge is an mixed breed...float and frame is dredge builders...pump is pro line and flare is The sluice that came on it was a homebuilt one..no o/u just a sluice.

 

[panningjack]

What kind of jet?

 

[pippinwhitepaws]

sounds t me as if you are not classifying the material put in the sluice...
rocks implies stones large enough to be removed by hand...as you should/...lose gold if you expect the water pressure to remove stones.

 

[omnicron]

No idea of the jet manufacturer... Rocks stones cobbles...what ever you want to call them I remove the ones that I know will cause plug ups...the rest I'll suck through. It seems like its the smaller rocks that are causing the piles. I've watch the sluice while sucking material and the rocks make it past the third riffle then get stuck.

 

[chlsbrns]

HAHAHAHA never ever do such a bonehead move to ruin a prtfectly good nozzle. O told ya a dozen times KISS-keep it simple man as ifn' ya can't seem to get a simple o/u to work how in the name a LL are you a gonna get a much more worthless convaluted 3 way to work?? Please just stand back and think for a minute?John

HAHAHAHA like putting a clamp on a nozzle will ruin it!

Keep It Simple Stupid HAHAHAHA doesn't get much simpler that a simple clamp!

"The problem lies that the larger rocks, 1.5" and above wont clear off the sluice"

So keep those rocks out another way if you think it's a bonehead move to stop the larger rocks from entering the nozzle.

 

[chlsbrns]

Why would I do that! I would be taking a 4" dredge down to 2 1/2 or something. I would then slow down production moving rocks and more rocks instead of just sucking them up. Besides I'm not having plug ups... just rocks piling up on my sluice.

You would do it to stop the larger rocks causing the problems. No larger rocks = no larger rocks piling up on the sluice.

It would not make it a 2 1/2" or something dredge it would simply stop the larger problem rocks. The finer materials containing the gold will not be obstructed.

Let us know how you solve the problem since you are unwilling to take 5 minutes and a buck to try something that will work.

 

[Oakview2]

There is a lot of experienced dredgers on this board. Post some detailed pictures or a video, and they can probably solve this PDQ

 

[chlsbrns]

The problem lies that the larger rocks, 1.5" and above wont clear off the sluice.

It seems like its the smaller rocks that are causing the piles.

Is it the larger or smaller rocks piling up?

 

[omnicron]

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. 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. Your solution is just assnine, it would be faster to use a gold pan at that point. Oh and by the way, John has more experience dredging/prospecting they just about anyone on this forum.

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

Pics:



Where the soap is, is were the rocks pile up
Im going to try this....

 

[russau]

im assuming that reading this thread that you dont use a dredge tender. usually, in most of the areas i dredge,the gold if fine(no nuggets) so i try to run my sluice in my 4 inch dredge as flat as i can,but i need a tender todo that. in other areas(states) i have more of a drop on my sluice to clear then rocks so they wont loadup.ive never had to screen back as far as your wanting todo!my sluice is a homemade 16x 48 over under made from ABS plastic.from what your saying you need more drop on that sluice.engine speed is fine,thats about where i run mine.lets hear how this setup your wanting to try works.plus i never run a restricter in front of my nozzel! thats what i use my hand for.and i watch for that particular size/shape of rock to keep it from my nozzel.

 

[Jason in Enid]

If rocks are piling up in your box you either need more flow or a steeper angle or both (unless you are purposely running flat like russ mentioned). You said this was a frankenstein setup, are you sure the box size is correct for the pump / hose size? Are you sure your pump impeller isn't ground down by sand from the last user? All hoses free of holes and all fittings tight? You would be shocked at how much a change in flow you get from a leaky hose or a poor connection.

 

[omnicron]

The gold I'm getting is also fine and I do not have a tender...my kids are supposed to be doing it but their attention span is about 30 seconds...unless it's their PS3!

I'm going to try this *screen* I have 2 pieces one about 1/2 the length and if that doesn't work then I'll try the longer one.

If this doesn't work then I guess full throttle and a flatter sluice will be on the list.

 

[omnicron]

If rocks are piling up in your box you either need more flow or a steeper angle or both (unless you are purposely running flat like russ mentioned). You said this was a frankenstein setup, are you sure the box size is correct for the pump / hose size? Are you sure your pump impeller isn't ground down by sand from the last user? All hoses free of holes and all fittings tight? You would be shocked at how much a change in flow you get from a leaky hose or a poor connection.

Hoses are brand new, pump is perfect...Proline HP350, the box is 15x48"
If I increase the angle any more my riffles start cleaning out to much and less the riffles take over a minute to clean out

 

[goldgit'r]

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