Dredge/Trommel Hybrid ?

oragonads · Oct 12, 2011

Has anyone ever seen, built or designed a dredge with a trommel somehow mounted to the frame? I've been picturing one in my head for a while now. I know weight would be a problem. But with a trommel classifying the material down you wouldn't need as large of a sluice.

Probably a stupid idea but I can't get it out of my head. :icon_scratch:

russau · Oct 13, 2011

why would you need a trommel when you have the dredge doing your classification for you

the extra weight/movement of the trommel would affect/messup the operation of the dredge/sluice!

SunshineMiner · Feb 20, 2015

I realize this is old.. But I've been thinking on this as well Oragonads.. I think the trommel would have to be set up lengthwise on the dredge frame, and have troughs to direct your flow. Tailings would be directed off the side using a chute.. Would just need bigger floats to compensate for the weight. And I do concur that you might be able to get away with a smaller sluice.. 1/2" classifier on the screen and boom. good to go. As for the dredge doing all your classifying for you? What about those 2-4-6in rocks >.> Not really classified if its rolling through your box and kicking out the smaller stuff :O

Reed Lukens · Feb 20, 2015

That's why you have screens to different sections

specksandflecks · Feb 20, 2015

If you did something like this 'right' you would no doubt get better recovery. How much better? That depends on a few things. Would it be a significant enough improvement to warrant the extra cost and complexity? That probably depends on whats motivating you. Sometimes people do things better just for the satisfaction of having something superior.

Vance in AK · Feb 20, 2015

I agree with what I think Reed is saying. Double & triple sluices with classification. Different riffle setups in the various sluices. A LOT less monkey motion.

goldog · Feb 20, 2015

Sometimes there are solutions in need of a problem. Modern dredges do pretty well at sorting the material.

Why do we want to "improve" it? Because that's what we do. A bigger trommel so you can have a smaller sluice? Ya gotta ask yourself what's the return on that?

Hoser John · Feb 21, 2015

KISS-keep it simple and stupid then you will prosper. Convalution is never the solution to gold recovery-John

Reed Lukens · Feb 21, 2015

Like our old American 6" that used a 1½" powerjet out of the hopper to feed the fines sluice up top. It was a great dredge :evil6:

Vagadero · Feb 22, 2015

Reed, what was the disadvantage of this setup?

SunshineMiner · Feb 22, 2015

Wow Reed! That setup looks pretty nice

I'm assuming all the smaller stuff just keeps dropping down and the bigger stuff rolls off the top? I've always been interested in how they worked.. I've always thought they looked like material can go past the initial classification spot for the side sluices and end up flying out the middle sluice where im assuming most of the bigger rocks go :x. I'm off to search and educate myself.

As for having the trommel set partially in the water.. I think thats feasible as long as its all stainless obviously. If its sitting in the water.. scoops or fins to spin it using the flowing water? oh just get a chain drive! And from the look of Reeds picture.. That thing would have no problem lifting its material into the hight of a screen!

But this is all just theory and fun talk. I see where you guys are coming from with the bigger engine requirements and such :x

And Hoser.. I believe its Keep it simple stupid.. not AND stupid

But then again, im still learning.. a lot :x

Edit: AHH HA! Found some nice little detailed pics of a previously for sale triple sluice that shows how the water is diverted to the other two sluices:

Vance in AK · Feb 22, 2015

SunshineMiner said:
Wow Reed! That setup looks pretty nice I'm assuming all the smaller stuff just keeps dropping down and the bigger stuff rolls off the top? I've always been interested in how they worked..

Edit: AHH HA! Found some nice little detailed pics of a previously for sale triple sluice that shows how the water is diverted to the other two sluices:
View attachment 1123093

That picture with the triple sluice is NOT (I believe) a stock setup. Keene did a much better job. Don't have any pics of my old one.

As I recall the American dredge in Reed's pic had a sump the fines went into & they were then pumped to the upper sluice. But that's me recalling & that's NOT always an accurate thing!

Hoser John · Feb 22, 2015

You got it VK it was a hoot to convalute that much. Folks get po'd when I say the Keep it simple stupid as they think I'm calling them stupid :laughing7:

so added a word to try and de-escalite blood pressure on this pressure cooker. Thanks Reed as haven't even seen a pic of one of those in many years.What a hoot cool-John

Reed Lukens · Feb 22, 2015

Vagadero said:
Reed, what was the disadvantage of this setup?

The only disadvantage was the old cast iron opposing crankshaft Briggs motor that was notorious for breaking a shaft but that one worked fine for many years. On this one the sump was in the front just after the header and it sucked the fines into a tube that put them into the upper sluice. The newer models had the sump at the end of the lower sluice. It was a great dredge with great recovery. We actually high lined the entire dredge- all set up - back out of the river and let it down onto the trailer when finished. With the old indoor outdoor green carpet up top in the fines area is was easy to see the gold as it came out of the small header and piled up about a foot down the sluice. Then we had regular carpet the rest of the way down the flared sluice and the gold all settled out into that sluice. This was a great and fun design from Alan Trees back in the day that he still uses in his larger dredges today.

http://www.golddredgebuilders.com/6_super.html

specksandflecks · Feb 22, 2015

Reed Lukens said:
The only disadvantage was the old cast iron opposing crankshaft Briggs motor that was notorious for breaking a shaft but that one worked fine for many years. On this one the sump was in the front just after the header and it sucked the fines into a tube that put them into the upper sluice. The newer models had the sump at the end of the lower sluice. It was a great dredge with great recovery. We actually high lined the entire dredge- all set up - back out of the river and let it down onto the trailer when finished. With the old indoor outdoor green carpet up top in the fines area is was easy to see the gold as it came out of the small header and piled up about a foot down the sluice. Then we had regular carpet the rest of the way down the flared sluice and the gold all settled out into that sluice. This was a great and fun design from Alan Trees back in the day that he still uses in his larger dredges today.

View attachment 1123128

This is awesome. This thread has taken a turn for the better. How much lower did that sit when running? Sumps seem like a good comprimise between 'static' classification and full on trommel/shaker classification. Also the seperate recovery area.

"This was a great and fun design from Alan Trees back in the day that he still uses in his larger dredges today." Whats your thought on west coast (WA,OR,Ca) use? 6" and up, 8" and up?

What do you think of a dual sump setup? 1st sump right off the flare in place of highgrade section, 2nd sump immediately following the undercurrent screen?

-About that boulder on the far left... Dono for sure looks like it says Sierra Blaster on it though? :bom:

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Reed Lukens · Feb 22, 2015

It sat a lot lower in fact I had to put a 5 gallon barrel up front to keep the motor out of the water and level it out.

specksandflecks · Feb 22, 2015

Looks like you can set separate pitch for each box independent to? That does look like it would be fun to operate. I bet that highgrade section in the fines box made sampling go quite a bit faster also??