A Manually Operated Reciprocating Concentrator

[Duckshot]

Here is something I have been playing with. it is like a rocker box but one end slides and is shook side to side instead of rocking. It seems to work and might be useful for some applications. Denser materials separate to the bottom of the "pan" as the pan is shook, the theory being that gold wont be able to travel up the near vertical wall at the exit end. As more dirt/water slurry is added, the lighter materials make it over the wall and out of the pan.

Anybody using one of these?

Questions, comments, and criticisms welcome.

 

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[Bodfish Mike]

Nice I like it -- thinking outside of the box (or in this case inside the box)
I built a rocker box and it works good but now you have me thinking.
Mike

 

[arizau]

To simplify your design you can actually make it on a rocker box base!

Size the closed bottom box so that it sits loosely in a frame that allows it to slide side to side and is bump stopped at each edge. When in operation the abrupt stops will add additional agitation promoting settling and quicker ejection of waste over the end. I would design the box width about one inch narrower than the width between the stops. Teflon furniture glides on the bottom of the box and on the side walls on the ends will probably make it slide easier. A fairly long rectangular box is probably best since the material will have more time to settle and classify as it works it's way to the exit IF it is added at the end opposite of the exit.

The main drawback that I can perceive is that you will end up with an excess amount of concentrates especially if the sides of the box are tall.

Good luck.

 

[Duckshot]

This one is about 8-1/2" wide and is built from the wretched remains of my first rocker box. The one I built without the apron that makes a rocker box a rocker box. I want to sincerely thank you Arizau. You deserve recognition as one of the persons who got me thinking about this. Remember our conversation in the Sluicing section under the thread "Rocker Box?"

http://www.treasurenet.com/forums/sluicing/526325-rocker-box.html

That's where this all started in my opinion.

 

[deserdog]

Does the bottom end stay stationary?

 

[Duckshot]

Does the bottom end stay stationary?

No.

The bottom "pan" end slides side to side riding on that white looking board that is made of plastic. The other end is on a pedestal with a pivot. I considered rollers or wheels, but they would likely clog with sand and grit in short order. I am thinking of anchoring a polished metal rod to pivot in the center of the pan or exit end, then ride the rod on 1" -1/2" PVC pipe sectioned in half and fastened round side up to the top of the tub.

It slides easy enough the way it is, the plywood bottom of the pan riding on the plastic board. The bottom of the box at the end is lubed up with bar soap. Irish Spring brand, if I recall.

 

[Bodfish Mike]

Now hook up a 18v sawzall to the box with a hose clamp or zip tie for speed control and you have a powered box. Of course it will be illegal soon but then go back to manual.

 

[N-Lionberger]

I like the idea of the keeping the head pinned and reciprocating the end of the box, like in a pan. How did you construct the apron? I have made a few rockers and have found a true homemade punchplate works best, things like expanded metal and hardware cloth the water falls through too fast, having good spacing between the holes really helps the wash action with the minimal water involved.

 

[Duckshot]

There is no apron. But, it works by the same principle as aa rocker box apron as far as I can tell.

The diffuser plate is just plywood with 7/8" holes drilled into it. The piece of 1x4 near the center of the box is a baffle, meant to keep everything under water and reduce floaters. It only dips into the pan's level line by about 1/4". Just enough to give everything a push down underwater. I'm not sure if it is even nesesscary. Then again, the baffle might be key too. I will have to play around with it some more. Maybe a rubber flap would do it better, I just don't know yet.

I'm going to try it on a steeper angle too, the slurry seems to hang up a little too much going downhill. And, increasing the slope will make the amount of concentrates held less, as well as shortening the distance in which heavies get to work their way down. Maybe. So much to play with! : )