Mini Sluice, questions about recirculation/angle

[outwardjourney]

I got this sluice from a friend who was selling off his equipment. This was the last of it, still new in the box. I wanted to get this to make a completely self contained recirculating sluice for ultra fine cons. The issue is sluicing is a new area for me. I am trying to find out what size pump I need, and what angle the sluice should sit at. Below is an image and the dimensions of the sluice.

Thanks!

He called it a bucket sluice or mini travel sluice. Doesn't look like a bucket sluice to me. But see attached for picture.

The dimensions are about 18" long, 6.5" wide and about 3" high. 18 x 6.5 x 3

How do you guys determine what pump and angle it should be at knowing just the dimensions?? Is there a formula that I missed? Searched everywhere and was told to ask you fine gents here on the forum!

 

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[fuseboxxx]

Should be about an inch drop for every foot of sluice you have. Example. If you have a 4 foot sluice you would need 4 inches of drop from top to bottom

 

[outwardjourney]

What do you think I would need pump wise? The general size I see everyone talking about is 1250gph, but how do they come up with that number? And that pump size seems rather big for a 6" wide sluice. Of course I can't find anyone with a sluice this small. The bucket concentrator sluices may be narrower than this sluice, but they seem to work with a 200-750gph pump.

Anyone?
Thanks for the reply! Slope seems simple enough.

 

[fuseboxxx]

You should use the creek for water supply. Otherwise you will have to get some kind of header box so the pumped water won't spill out of the top. When you use the existing creek water you want a nice current at the top that forms a V.

 

[outwardjourney]

This won't be a creek sluice. I want to make a self contained recirculating sluice with this little guy for a final run through of concentrates.

 

[fuseboxxx]

Then you will block off the head of the sluice. 1250gph should be great on that. If its too much add a valve so you can dial it down. Go to YouTube for ideas for the head. It will show you how to make the water smooth as it goes down the sluice because you need an even flow going through

 

[goldenIrishman]

Block off the upper end and set up a 750 GPH 12 volt bilge pump with a valve as mentioned above. The amount of water you need is dictated by the width of the sluice and what kind of riffles you're running. NOT the length or height. How you adjust the flow is determined by how you classify the materials that you're going to be running through it. The smaller you take it down in size while classifying the less water you're going to need to move the materials through the box. The smallest size you should classify down to is estimated by the largest size of gold you expect to find in your area. ALWAYS check your screen before dumping it out to make sure you don't miss an unexpectedly large nugget!!! Since you're planning on using this as a clean up sluice for your cons you don't want much angle or flow. Loose the riffles and just run the rubber mat. You don't need the riffles because it's already concentrated and having them would be like reinventing the wheel. With just the rubber mat in place feed the box with a tablespoon and adjust the flow with the valve to where you're just moving black sands and not gold. I am assuming that you're going to screen the small rock out of the cons before running them. Don't forget to add a drop or two of dish soap or JetDri to your water to prevent floaters.

Judging by the picture you posted, I'd guesstimate that you're going to need about 3-1/2 to 4 degrees of downward angle on the box at 300 GPH to have it work with cons. If you can go flatter with more water do so. Save your tailings and re-run them to make sure you have an angle that gets all the gold.

Setting up a sluice is not rocket science but it does take a little practice. Don't be afraid to experiment! With a re-circ system you can always re-run your materials if you goof it up.

 

[fuseboxxx]

Block off the upper end and set up a 750 GPH 12 volt bilge pump with a valve as mentioned above. The amount of water you need is dictated by the width of the sluice and what kind of riffles you're running. NOT the length or height. How you adjust the flow is determined by how you classify the materials that you're going to be running through it. The smaller you take it down in size while classifying the less water you're going to need to move the materials through the box. The smallest size you should classify down to is estimated by the largest size of gold you expect to find in your area. ALWAYS check your screen before dumping it out to make sure you don't miss an unexpectedly large nugget!!! Since you're planning on using this as a clean up sluice for your cons you don't want much angle or flow. Loose the riffles and just run the rubber mat. You don't need the riffles because it's already concentrated and having them would be like reinventing the wheel. With just the rubber mat in place feed the box with a tablespoon and adjust the flow with the valve to where you're just moving black sands and not gold. I am assuming that you're going to screen the small rock out of the cons before running them. Don't forget to add a drop or two of dish soap or JetDri to your water to prevent floaters.

Judging by the picture you posted, I'd guesstimate that you're going to need about 3-1/2 to 4 degrees of downward angle on the box at 300 GPH to have it work with cons. If you can go flatter with more water do so. Save your tailings and re-run them to make sure you have an angle that gets all the gold.

Setting up a sluice is not rocket science but it does take a little practice. Don't be afraid to experiment! With a re-circ system you can always re-run your materials if you goof it up.

Yeah..what he said. Lol

 

[outwardjourney]

Awesome! Now, one last question... I have some old fountain pumps that are essentially pond pumps, and if I remember correctly, one is adjustable from 400-750gph. Does it matter what kind of pump it is? I mean, does it need to be a sump/bilge pump for a reason?

 

[B H Prospector]

The main reason for using a bilge pump is it can handle dirtier water than a pond pump. A pond pump like you discribed will work but you will be replacing it sooner.The irishman has good ideas.

Good Luck!

BH Prospector

 

[goldenIrishman]

You should be able to get away with using a fountain pump as long as it has enough flow. Your cons are already clean for the most part so you're not going to have a lot of crud going into your water. Even so. build yourself a pump box out of window screen or nylon stockings to filter the water before it enters the pump. It's cheap insurance. That little bit of Jet-Dri will also help to settle out any crud from the water quicker.

One problem you might run into with a fountain pump (Or any pump for that matter) is loss of flow rate due to a limited head height or how high it can pump water from it's location. The higher a pump has to lift the water to it's outlet, the less flow it's going to have due to gravity trying to pull it back down. Try to keep the vertical distance between the pump and the sluice as short as possible. Keep your hose between the pump and sluice as sort as possible as well. Friction will also slow the water and more hose means more friction.

 

[bion]

Hi all.I am mew in this forum nd mi inglish is bad.I want to build sluice but i dont know the dimensions and the angles of the riffles, somebodi can tellme the sizes of hungarian riffle "z" and this angles(en mm)?
Thanks very much.

 

[Timberdoodle]

A couple notes here on figuring the volume. If you calculate the approx. area of 6in wide at 1/2 deep of water you will have an area of 3sq inches. Using pipe calculations for a 2" pipe (3.1sq inches) at 750gph will give you a flow rate of 1.2 FPS. pretty good rate for getting fine gold. The only potential problem I see may be the fact that the sluice you want to use has riffles which may pack up and not clear properly at this rate. If you find this is the case, you may want to change the riffles out for 1/2 expanded since you stated that you are going for fine gold and probably don't want them anyway.

Just saw Goldenirishman already mentioned riffles- oops

 

[outwardjourney]

A couple notes here on figuring the volume. If you calculate the approx. area of 6in wide at 1/2 deep of water you will have an area of 3sq inches. Using pipe calculations for a 2" pipe (3.1sq inches) at 750gph will give you a flow rate of 1.2 FPS. pretty good rate for getting fine gold. The only potential problem I see may be the fact that the sluice you want to use has riffles which may pack up and not clear properly at this rate. If you find this is the case, you may want to change the riffles out for 1/2 expanded since you stated that you are going for fine gold and probably don't want them anyway.

Just saw Goldenirishman already mentioned riffles- oops

Where did you come up with that math? Is there a formula floating around that I should know about?

 

[Timberdoodle]

Where did you come up with that math? Is there a formula floating around that I should know about?

First you start with the basic width/height of the water to get the area in square inches. Once you have that you can compare the area to the area of a circle. Radius Squared *3.14 will provide the area of a circle. Alternate method - You can divide the area you have by 3.14 and then the square root of the answer to give you the radius(double for diameter)

Once you know the equivalent diameter than you can use online tools like FLOW RATE CALCULATOR to calculate velocity, flow rate etc...

It's not a perfect way to do it because angle changes will determine changes in velocity and water depth, but it does provide a good starting point.