Clarkson riffle set up

Trinity_miner

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Sep 23, 2014
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I'm currently building a 5' long x 10" wide highbanker. i have the whole unit pretty well finished. I'm just waiting on my modified clarkson riffles from heckler fabrication. i am going with the 3/4"x 1/2" lip size. The plan is to set them to the 15° uphill angle and 2x riffle heigth spacing per the clarkson study, but i was wondering right about how many gpm should i run with these things in a 10" box ? I'm trying to decide which pump to pick up for my aplication. any help would be greatly appreciated!
 

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Timberdoodle

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Oct 17, 2012
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Hopefully there are others on here with more experience with this, but I will give my thoughts.
Clarkson's require fast water flow to generate their strong vortex, 5 fps minimum is mentioned by heckler fab. so I will use 6fps as the speed of flow. If you have a 10" wide sluice and factor a water depth of 3/4" that gives a area of 7.5" travelling at 6fps. This amount of area and flow speed will utilize 140gpm, so a pump capable of 150gpm I would think should work well as long as the delivery distance is not long or uphill much. The unknown question is how much flow is lost through restriction of spraybars etc.. that hopefully some other folks can help answer.
 

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Trinity_miner

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Sep 23, 2014
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Thanks that helps a bit. It seems less then i was expecting. I hear tale that these things need near 350 gpm but wasn't sure how accurate that is. I haven't been able to find a solid for sure number on flow.
 

Timberdoodle

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Oct 17, 2012
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I remembered Goodguy is running a Clarkson highbanker/trommel. Probably best to check with him on flow/ water depth etc.. simply running 1 1/2" depth could run around 300gpm. He will steer you right.
 

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Trinity_miner

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Sep 23, 2014
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They recommend from 350 to 400 gpm. But that seems way way fast. Not to mention a pump that can move that volume is not cheap at all.
 

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Trinity_miner

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I was just looking at those on ebay. i think i may pick one up when i can afford it. That price isnt too bad. cant wait to move some dirt!
 

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Trinity_miner

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So I'm having second thoughts about using the clakson riffles. i want to use them but a 4 inch pump is a whole lot of pump. Not to mention got to have a huge volume of water to keep it workin. I'm wondering if i wouldn't be better off using some variation of the hungarian riffle. i really would like to use the clarkson as i have heard nothing but good about it. I'm on the fence. what do yall think?
 

SLNugget

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Sep 25, 2013
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So I'm having second thoughts about using the clakson riffles. i want to use them but a 4 inch pump is a whole lot of pump. Not to mention got to have a huge volume of water to keep it workin. I'm wondering if i wouldn't be better off using some variation of the hungarian riffle. i really would like to use the clarkson as i have heard nothing but good about it. I'm on the fence. what do yall think?

IMO the size gold you typically recover in your primary area should dictate your equipment choices.
 

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Trinity_miner

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Sep 23, 2014
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In my area we have some decently coarse gold. some smaller stuff too but it tends to be lots of medium sized flakes and decent sized pickers aren't uncommon. the reason i wanted to go with the clarksons is because i have heard that they do pretty good work on fines as well as larger stuff while keeping a good recovery percentage. but am concerend with the creeks and streams i work not being able to keep up with the 4" pump and just the price of the hose and rest of the stuff to go with it.
 

Timberdoodle

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Oct 17, 2012
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I have been very impressed with using 1/2" raised expanded over vortex matting for fine and medium gold. If it was me, I would build a 2 stage system each being 2 1/2 feet long if you want a total of 5ft of sluice. Reduce the width of the upper sluice to 6" and run Clarkson's over vortex then widen to 10-12" and use expanded over vortex. Each section should be independent for angle adjustment and incorporate a hydraulic ramp in the flare to disperse energy and flow coming from the upper sluice across the wider sluice. This would allow for a smaller pump and a wide range of processing ability. Just a thought.
 

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Trinity_miner

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Sep 23, 2014
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I already have the box frame and all built, just tryin to decide on riffles. I have 2 feet of raised slick plate before my 3' riffle section. And timberdoodle I like that idea, it goes right on track with the clarkson study. But ill have to save that design for the next one as i would have to basically tear everything down and start from the beginning. I think i will ultimately have to find a set of riffles that will work with my 10" box and the velocity required. I still may go with clarksons and just build several riffle trays for different situations. I may end up goin with the 4 inch pump for the clarksons and use my mining buddies 1 1/2" honda pump to run a set of hungarians when necessecary. How much water should the hungarian riffles run? Im trying to figure out how to build a set of them up without a metak break. Thanks guys!
 

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