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Sluice Box Design.


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I was standing in line at fry's buying supplies for thurdays RRPC meeting ad a guy saw my RRPC shirt and asked me a question about Sluice boxes. Actually he asked me a bunch of them. It got me to thinking , so i thought i would get your opinion .

What is optimal length of a sluice box and is it possible to make it too long ?

I gave him my addy and he stopped by for a couple hours. We came up with a design that could be 12 feet long or shortened to 4 feet in less than a minute. We priced out parts and complete without matting is only minimal. Seems more of a problem finding enough water than building it... but hey bilge pumps are fun.

Thanks in advance.

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4' is more than sufficent when preclassified to 1/4" minus. Unclassified better add a couple of feet. Riffles,flair to collect more water pressure,and expanded metals also make a big difference also. Bilge pumps :th: tinker toys in a mining world-John

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Thanks John ,

we were deciding on about 12 feet long and a width of 6 inches. it was going to be Z shaped with 3 four foot sections and a 600 gallion pump.

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Sluice box design is based on multiple factors. The maximum size material you run through it, the way its fed (continuous feed, dump in type feed, or otherwise) volume of the material continuously running through it, the amount of water available, the type & size of the gold particles. Consequently, each situation varies depending on those & other circumstance.

I build my own out of sheet metal. Using a sheet metal “break” to make 3 section boxes in 4 ft each lengths. With each section just slightly wider the than the one preceding it. That way, if need be the boxes can be overlapped several inches & bolted either 4, 8 or 12 ft long. That way they fit inside one another for compact transport, and you have enough length for about any situation.

I prefer a header type crash & boil box out of thicker metal coming off the wash plant so the material drops vertically into the crash box, them changes angle & runs down the sluice. Along with a way to add an additional volume of water to crash box, without increasing the waters velocity running down the sluice box.

As well as an easily adjustable flap unusually made from fairly thick conveyor belting at the junction of the crash box, where it comes together with the sluice box. The flap gives you a degree of control on the water velocity, as well as smoothes out the water flow evenly across the sluice box entry.

The riffle configuration is dependent the size, weight & character of the placer gold in the material you are running. Expanded metal, riffles & matting should be configured so they are easy to remove, fines remaining in the box & once everything is removed (except the gold bearing fines), you can use a square point shovel & hose to wash all the fines into a container at the end of the sluice box, for final clean up when you choose.

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Thanks Elder ,

Most of that was already known but great info anyway. After brainstorming ( it was a very small storm ) this was our thought process.

1. By utilizing 12 feet you could add all types of riffles , wire , and matting for all gold sizes and types.

2. By keeping it narrow to around 6 inches you could maintain water flow velocity with minimal loss.

3. Most of his material will be around 1/8 inch classifier size or less so most gold will be flakes.

4. He plans to run material that was deposited at the base of an old commercial mining operation that ran 80 years ago... the powdery stuff . it is at least 3 feet deep and the size of a football field so plenty to run but he wanted to stay small sized.

Thanks again for the info !!!!!

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Like elder-miner, I too use a "Long Tom".

Inter locking sections that I can stretch out to as much as 21 ft.

8" wide, 4" deep.

I have two others 10" wide and 4" deep.

Each of those will go up to 16' long.

When I was constructing them, I was instructed to have the boxes at least 8" wide.

After using these boxes for the last 4 yrs, I really prefer the 10" wide boxes.

I can run more material in the same amount of time I would run the 8".

Here's a pic of my 8" at 21 ft long.


The "crash box" has an opening for hand feed, water is fed to the box by a 3" pipe connector that provides water flow and also accepts my dredge hose. The interior is baffled to break up the bulk of material and mix it more throughout the water flow.


This is the "funnel" I use to collect water. 24" wide reduced to 4" and 6" deep with a 3" hose.


The legs of the sluice are 1/2" conduit. I put tennis balls on the legs as feet, to keep it from sinking in the gravels/dirt/sand.

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Awesome pics Dave.

This is more along what we had thought of. Then we decided that due to some possible clearance problems we could sort of stach the 4 foot sections like a dry washer and install the shrouds over the transitional ends. Space sometimes gets tight with alot of trees. But in the open could be converted back to a 12 foot long like your pic. Thanks Dave !!!

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The 8" is as narrow as I want to get.

The 10" is pretty much perfect.

Goin' to a 6" you're headed toward a cleanup size.

But, as mentioned before, it kinda depends on what

material you're runnin' and size of the Gold you're gettin'.

It's all a test.

If ya find Gold, ya pass.

If ya don't find Gold, ya fail, except for all the fun yer havin'. :brows:

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Space sometimes gets tight with alot of trees. But in the open could be converted back to a 12 foot long like your pic. Thanks Dave !!!

I set "Tom" up at the edge of the stream.

I can stand on the low bank to tend the sluice, and

the sluice is located where I can at least set it for 12 to 16 ft. up/down the stream.

The bottom end of the sluice is far enough off the ground to where I can easily set a 5 gal bucket

to catch the cleanout.

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