Started building a 6" dredge

[principedeleon]

Hello everyone on here; im looking for some advice with my 6" dredge sluice box, Is the first thing ima start with.

I have a P350s pump being coupled with a 16hp briggs engine at a shop.

I want to know if my configuration of pump with engine and a quad jet can produce the enough water to make a sluice box 24" wide and 6' long work properly. Im planning on making it just like ross 4" over and under modifcation; just with drop riffles in the undercurrent.

I will be running it in production mode high RPMs.

Also what riffles work best at the same drop riffles angle. I believe i read something about that drop riffles work best straighter.

Ill post more pictures as i start getting deeper into it; but this is what i have.

 

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[omnicron]

Don't know what a Ross 4" over under is...
Drop riffles work good in the underflow but raised expanded over deep v or carpet works much better in the undercurrent section.
As for your upper riffles, you need to figure out how much flow you'll have in your box first otherwise you could end up with riffles that are to tall.

Honestly consider some GH matting. For what you would spend in metal, welding and fab, you could go with that matting and once dialed in have a very high capture rate without all the trial and error.

 

[Reed Lukens]

You should be running 2 of those motors for a 24" box and it's not enough with one pump to run a 24" undercurrent box.

 

[omnicron]

Might be enough water for GH mat though...You want like 2 or 3 inches of water over the top of gh mats and lots of pitch.

 

[principedeleon]

Okay i said his name wrong sorry, is Reed and im trying to work with most of what i can find here in the dominican republic and i cant wait to i order this matting since i now have no dredge the river flooded and all i have is a piece of the frame where the dredge was attached to with a steel cable. I think a log hit it and it took the dredge for a ride to a 30' waterfall and is somewhere buried around there.
Hopefully i find her when the river cleans up a bit.

But anyway The drop riffles is from a truck bed linner is tough and lightweight. I just need to cut it and fit it into place. I havent been able to find raised expanded just the normal expanded.

 

[Reed Lukens]

Normal expanded works fine. Don't go larger than 20" wide because 24" is just too much to make a mistake with. If the motor can be turned down a bit with a 20" wide box then you still have a working machine. If you start at 24" and it is too big, it's back to the drawing board. A quad jet will help but i usually run 800gpm minimum from the pump with 1000gpm+ preferred. The biggest problem will be the dredge hose length because with maybe 1200gpm going through the box with that motor & quad jet you will need to be running in very shallow water with a short hose. I wouldn't start with more than 12 feet of hose with the one pump unless you get it for free. You will need to cut more & more of the hose off until the needed suction is obtained You're probably going to end up with a 10ft hose give or take ;-)

 

[omnicron]

Reed, normal expanded? Thats not going to have a lip to create the small vortex's unless I'm missing something...
I'm just asking, your the expert...

 

[principedeleon]

okay so normal expended with miners moss work better then the drop riffle system ? i never tried that before.. i aint looking to capture flour gold more like those small tiny gold that you could just pick up with your fingers, but also want to protect them bigger pieces also in my undercurrent.

so theres no chance that even with the expended & moss i could have it work right at 24".. how about using a 1/4 or less punch plate as a clasifer for it wont steal too much water ?

 

[omnicron]

If you use miners moss, you'll have to have ribbed carpet under to stop gold migration...also you'll have 4 times the cons to process... Also to only care about the small pieces that you can pick up is well, stupid. The small gold adds up very very fast. Fine gold is the whole reason for a undercurrent sluice.
P, v-rib mat under the expanded in your undercurrent works perfect with ZERO loss. If you have ever delt with v ribbed matting you should know what I mean, The gold just doesn't wash out, it takes a flow from the side or turning it upside down to wash it. Gold is heavy, once in the groves it's not going anywhere. Even ribbed carpet will work well in both the top and bottom of your sluice. Miners moss is so overrated....I does have its place though but IMO its not in the underflow section.
I like to use 3/16 punch plate for the undercurrent section. It allows enough water but blocks the larger material from entering. !/4 pp in my opinion will allow to much material in the underflow and plug it up.
Also so you know, o/u sluice are not very good for sand. Your feed rate has to be right otherwise you'll plug up the lower section. If you dredging in sandy conditions you really have to slow down.

 

[Reed Lukens]

okay so normal expended with miners moss work better then the drop riffle system ? i never tried that before.. i aint looking to capture flour gold more like those small tiny gold that you could just pick up with your fingers, but also want to protect them bigger pieces also in my undercurrent.

so theres no chance that even with the expended & moss i could have it work right at 24".. how about using a 1/4 or less punch plate as a clasifer for it wont steal too much water ?

There is a chance that it may work at 24" but if it doesn't, it's worthless to you. Go 18" to 20" to be safe. For the undercurrent the normal expanded is what I use also in situations like this. What you have to worry about is the amount of sand going into the undercurrent so you're going to want to use no bigger than ¼" punch plate with maybe an 8" wide opening up to the flare because you will really need to limit the water going down below in order for the upper box to run. Run the undercurrent 1/2" to 5/8" high and it will work fine. Also if you have some 3/16 punch plate, that works great also. Everything that drops into the undercurrent should stay at the front but it may take some adjustment to run the sand out with that motor. I run ¾" on my 6" at 800gpm but 9/16" on my 4" which also runs on a 500gpm pump. The normal expanded will trap the gold just fine in the undercurrent while still being low enough to clean out the sands. You can use any carpet underneath. V-rib works fine. Watch the last section or part 3 of this video series.
https://www.youtube.com/playlist?list=PL39A9E7B702FF1B8A

 

[principedeleon]

the thing is that i cant get on my hand right now any special matting, not even the rib matting; i know it sucks but the gold we was finding wasnt soo small like i said most of them you pick it with your hand.. i was finding about a gram daily from just the gold that is in the material. bedrock was about 9 feet deep but the gold i found is in about as deep as 6 feet, then there is a softer material that likes collapsing and didnt produce me any gold.

 

[Reed Lukens]

Just use regular carpet or indoor outdoor if that's what you can get. The important thing is the expanded metal laid over it, so use whatever carpet you can get your hands on because the water flow is so low in the undercurrent that most of the gold will just drop and sit in place just under the punch plate. How big is your gold? The answer will tell you how big to make your punch plate. But still with 500gpm, 3/16" max is a good start for pp but you can adapt other styles if needed to reduce the hole size.

 

[principedeleon]

okay, ill reduce my box down 4". but isnt a 8" openning at the flare is maybe too small i had about a 12" opening on my 4" and it was bursting a ton of water with my quad jet.. it wanted to suck my arm up the hose..lucky the hose was too small lol

 

[Reed Lukens]

I didn't mean an 8" wide flare, I meant 8" from the head of the box down stream into the box to the undercurrent separation plate. I don't remember the flare width but you will need to keep it small for the motor like 14" wide x 6¼" tall

 

[principedeleon]

okay, i watched this before but im just watching it all over just in case i missed anything.. and how does angle iron riffles work ? have you tried this?

 

[principedeleon]

If you use miners moss, you'll have to have ribbed carpet under to stop gold migration...also you'll have 4 times the cons to process... Also to only care about the small pieces that you can pick up is well, stupid. The small gold adds up very very fast. Fine gold is the whole reason for a undercurrent sluice. P, v-rib mat under the expanded in your undercurrent works perfect with ZERO loss. If you have ever delt with v ribbed matting you should know what I mean, The gold just doesn't wash out, it takes a flow from the side or turning it upside down to wash it. Gold is heavy, once in the groves it's not going anywhere. Even ribbed carpet will work well in both the top and bottom of your sluice. Miners moss is so overrated....I does have its place though but IMO its not in the underflow section. I like to use 3/16 punch plate for the undercurrent section. It allows enough water but blocks the larger material from entering. !/4 pp in my opinion will allow to much material in the underflow and plug it up. Also so you know, o/u sluice are not very good for sand. Your feed rate has to be right otherwise you'll plug up the lower section. If you dredging in sandy conditions you really have to slow down.

I know omni i had a under section on my 4". The under current doesnt.need a lot if water to work properly is the top riffles and clearing the larger rocks.. How wide is yours and how high does water flow in your box in a working angle?

 

[omnicron]

My box is 20" wide and water level is about 4" or so.

 

[principedeleon]

How does the dove tail in the undercurrent work?
I was thinking of mixing it up with the dove tail riffles and drop riffles following after.

 

[omnicron]

I'm using gold hog mat. For the cost of the mat, it'll pay for it's self with a 98%+ capture rate real quick. It'll capture from -100+ up to nuggets.
P, just remember if you deviate from using expanded metal in the undercurrent part, your going to rob needed water from your top section. You don't have enough water as was stated by Reed, so I would just stick to using expanded.

 

[principedeleon]

I'm using gold hog mat. For the cost of the mat, it'll pay for it's self with a 98%+ capture rate real quick. It'll capture from -100+ up to nuggets.
P, just remember if you deviate from using expanded metal in the undercurrent part, your going to rob needed water from your top section. You don't have enough water as was stated by Reed, so I would just stick to using expanded.

i feel i have enough room to mix it up a bit.. reed also stated in his video about how keene riffles are king since they mix up the riffles for all kind of gold. i am going to refold the sluice box to 20 inches; should i have there enough water still to have a normal under and over box work properly ? isnt there is 6" dredges from keene using a 13hp motor and regular log jet working a 3 stage on a 20" box ? this is why i thought i could push it up a bit.i feel like im coming in under powered "/