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Building A 9'x3' Sluice Box For An Old 8" Dredge


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So we did end up pulling that old 8" out of the bush from an old mining camp (previous post). We're going to go through the whole thing and get it back up and running. Main question I have is about sluice box design. I've read "The Clarkson Study" a few times over the years and just re-read it. Did a bunch of googling, youtubing and searching forums, but its hard to come up with great information about sluice box design for a larger dredge like this. I like Keene's sump system for fine gold but I wont be building that. For the most part I'm going to use this on our claims that are on a larger creek. We do have fine gold but not a ton of it. What we do have is potential larger gold (1-5oz nuggets).  Most of the gold ranges from 30 mesh to 4 mesh.

Looking for links to good information and/or input on ideas on how to put a box together. Sadly when the old AMDS forum shut down I stopped keeping up with any other forums with new information after bouncing around a while. I can build/fab just about anything needed. Also curious to what you guys think about some new types of matting in a large dredge. I have all winter for the build.

Box is 9'x34". 1st 3 feet follow the flair angle till it meets the max width of the box. The old riffle set up leaves a lot to be desired. Had been thinking I wanted to do some smaller woven screen at the last few feet of the box for smaller gold and then talked to Mark Keene. He said they have been testing 1/4" woven mesh (1/8" thick) over expanded metal and it was really doing well. Dropped the water flow to 1/2 the rate when the screen was 1-1 1/2" above the expanded. 

Was thinking 1/2-3/4 woven mesh for the first 2-3 feet over a combination of Hungarian riffles and expanded metal ( separately, not on top of each other). Then 2-3 feet of just hungarian riffles. Last 2-3 foot maybe run a section of 1/2" woven mesh and then 1/4" woven mesh over a combination of smaller riffles and expanded metal. I would like to make 2 sections in there for some hog mat maybe. Also curious what you guys think of just carpet and moss over carpet in some of these different sections, what size riffles and expanded for the different sections also.

What do you think about this equalizing power jet design and hose attachment to the powerjet/flair.

Dredge came with four 18hp Vangaurd motors and two powerjet/flairs.

Any opinion on any part of this or links to information is appreciated! Thanks

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  • The title was changed to Building A 9'x3' Sluice Box For An Old 8" Dredge

My grandfather had a system similar to what you are wanting to build. His had the 1/4 mesh under the expanded so that it would catch the larger nuggets along with the smaller pieces. He had the 2 pieces separated with a couple of washers to create better catch for the small nuggets.

I remember having to take it apart to do a cleanup and saw a bunch of gold of all sizes. He always said think outside the box and try everything to make it work the way you want it. I still try that today.

If he still has the old sluice I will send you some pictures if I can locate it.

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7 hours ago, Valens Legacy said:

My grandfather had a system similar to what you are wanting to build. His had the 1/4 mesh under the expanded so that it would catch the larger nuggets along with the smaller pieces. He had the 2 pieces separated with a couple of washers to create better catch for the small nuggets.

I remember having to take it apart to do a cleanup and saw a bunch of gold of all sizes. He always said think outside the box and try everything to make it work the way you want it. I still try that today.

If he still has the old sluice I will send you some pictures if I can locate it.

Thats a pretty interesting way of using the woven wire. Never heard of that before.  Would be neat to see some pics if you end up finding them.

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Grand mother told me what happened to that sluice he had, he sold it to someone in Colorado after he built a new style out of nylon. If I can find out who has it I will ask him for some pictures of it. We had used it out there for several years and had great luck with it.

 

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Sounds like you’ve done your research. The Poling and Clarkson reports are great. 

Fine Gold Recovery of Selected Sluicebox Configurations 1989

Gold Losses at Klondike Placer Mines - Gold Recovery Project 1989

An Analysis of Sluicebox Riffle Performance 1990

A review of placer gold concentrate recovery and upgrade options 2011

I’m a carpet under miners moss guy due to Clarkson.

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On 10/9/2020 at 7:43 AM, Steve Herschbach said:

Sounds like you’ve done your research. The Poling and Clarkson reports are great. 

Fine Gold Recovery of Selected Sluicebox Configurations 1989

Gold Losses at Klondike Placer Mines - Gold Recovery Project 1989

An Analysis of Sluicebox Riffle Performance 1990

A review of placer gold concentrate recovery and upgrade options 2011

I’m a carpet under miners moss guy due to Clarkson.

Thank you Steve. Some of those I haven't read before. Great reads for sure. I've never seen actual 90 degree angle iron run in a dredge before. Its always been a modified type dredge riffle from Keene or Proline with more of a 45 at the top running flat with the box. The riffles in this old Dahlke are the same with the addition of 1 1/2 flat bar in some areas.

The way this box is set up with the header going from 24" wide to 34" wide over the first 3 feet would seem to me to be the best location for un classified 1 1/2" riffles for bigger gold. Then run a 3/4 to 7/8  wire mesh screen over smaller riffles and expanded for the next 3 feet. Last 3 feet run 1/4 mesh over small expanded. 

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