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commerical scale drywasher?


JasonG

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Is such a thing produced and sold? I've seen a couple custom jobs on youtube from a battery of 151's to a smaller conveyor type drywasher.

Has anyone built one that could handle more or less continuous feed from a say a 1/4 yard bucket?

Just curious how they scale up, what sorts of design lessons people have learned. Not finding much out there on the internet. Is it because at a certain point they just don't scale up and it's better to work with water instead?

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Not sure if I could find it again, but I did see one in action in an Australian video. It was being fed by a skid steer with a pretty big bucket. Sure did raise a giant dust storm! Memory says it had about three 18-24" trays maybe about 3' long

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Nope. Big ones are generally made up for the occasion. We had a couple of big boxes we made from a Cains Coffee cleaner. Lots of agricultural equipment for cleaning beans and nuts are nothing but drywashers.

A farm boy in Dove Creek could get you the boxes and blowers. Lots of ginning equipment could be had on the cheap. That shaker to clean rocks out of pinto beans is PERFECT!

Nice to see a post from you Jason! I wish I could tell you where there was specific stuff for sale. We did ours with the help of a chile farmer and an implement outfit that located used coffee bean cleaners. Basically all we did was stretch cloth over it, install a hopper and change the pulleys on the motors. It was fairly simple and cost about a thousand bucks for the used stuff.

That was 20 years ago but I bet you could get it done on the cheap.

The only trick I know is to kkeep the flow wide. A short wide table handles volume better than a long narrow one. And multiple levels allow more volume and flow rate with high efficiency...two boxes are better.

Edited by Bedrock Bob
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Do you think a swamp cooler blower would have enough volume? I could get those pretty cheap. Maybe fit it with a faster/higher power motor. Not seeing much ag equipment for sale on the western slope right now, might just be the season though, I'll keep an eye out.

Any idea for a inexpensive repurposed conveyor source? One like 10-15ft long, 18 inches(ish) wide...

Edited by JasonG
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Jason check some of the Australian sites.....when I was there I saw one being towed behind a truck with a front-end

loader on the truck. The dry blower being towed had it's own axle and wheels.

Also saw a gold wheel also had it's own axle and wheels....a monster for serious work....

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Not a swamp cooler..wrong blade design. You don't need CFM you need static pressure.

Grainger has high static blowers on the cheap. Car washes use them. Roof venting systems use them. They have a radial blade design.

Any cotton gin or agricultural plant uses them to move dust, chaff and grain.

An old sandblaster is perfect...they use one to creat vacuum and circulate sand.

Same fan as on a jumping balloon.

The bean cleaners are just a big box with a fan in it and a cam to provide vibration. Even a nice screen table to stretch cloth over. They use a lot of them here for pecans. I will see what I can shake up. I know I can get a suitable fan without a motor or engine...

Check out Grainger...search for "High static pressure radial blade blower" They have them in all sizes with or without motor mounting surfaces...this is what I use. A great big one that will power a huge drywasher is about $300.

Conveyors and elevators are available everywhere. No doubt you can find modular units you can put together for cheap. Again a simple conveyor designed for harvest will be cheap and available.

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Hmm that might be the way to go with renting, it looks like they aren't very expensive. You're right Bob, Grainger sells blowers new for about as much as I could build one myself outta scrounged parts.

I'll search the Aussie sites for some of their contraptions too and see what sorts of interesting MacGyverisms they got going on. If anyone has a functioning large scale drywasher they built I'd be interested to hear your numbers, like width/length of riffle tray and CFM/pressure of your air source. I think I can WAG it down to something that would work but would be nice to have some #' to base it off too.

I'm thinking three 24"x4ft units side by side, 5000CFM adjustable air capacity from a few high static pressure radial blowers. For a 1/4 yard (skid steer type or backhoe) bucket. Vibrating screen to 1/2" (not a lot bigger than that where I am thinking and I can detect it easy in the tailings for the rare piece). Is that about right? I'm just gauging air from my 141 that runs on about 250CFM. Screen would feed an adjustable hopper that I'll think more about later.

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Jason

Your CFM does not make much difference but your static pressure does. That is what lifts material. Multiple blowers won't get you more cfm or static pressure causa an impeller cavitates at a given sp. So you will need one fan for each box that will handle the pressure needed to lift material...and that is about 4" of mercury. CFM needs to be enough to fill the box and maintain pressure.

CFM is relative to SP as volts are relative to amps...4000 Volts won't start your car unless the amperage is there.

So a pressurizefd system will only push as much air as the cavitation limit of the fan. You can get more CFM out of two fans but you must double the duct size. So it is best to isolate your boxes amd blowers.

Our tables were about 36" wide and 48" long. They had a shaft that turned the blower with cams that made the whole rig jump. There was a strike plate undervthe cams that adjusted them up and down thereby adjusting vibration. One table fed thru a chute onto the second table and tailings slid down a launder to the ground. The rig was driven by two 220 volt 3 h.p. Baldor electric motors and we used a small Yanmar diesel generator to power it.

We fed and mucked with an old Ford backhoe and probably could process 3-5 cy perhour.

The screen needs to be about 3/8 Expanded metal. Any larger and the machine gets sluggish. We wound up putting 3/8 woven wire over the expanded metal to screen things a little tighter.

We had zero problems with the machines except with the cribbing. They would walk off the cribbing or walk away from each other and dump material. We needed to mount them on an old trailer to make them solid and provide some height for tailings to pile up. Mucking was a problem and we kept moving the machine with the bucket when we did. The launder chute got it away from the box but made a short pile.

As of three years ago that machine was still in Hillsboro. It could be available but there are no motors and the tables are probably rotten. I will see if I can swindle it for you. All together it will weigh about 500 lbs without motors or hopper. If I can get it you will need to find a couple big motors with the proper sheaves and fabricate a grizzly or trommel to feed it.

...then there is loading it up and hauling it.

I will be going up to Hillsboro on Saturday. If it is there I will do my best to pilfer it.

Hope the info helps and I will PM you on the machine.

Edited by Bedrock Bob
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Cool, that was helpful. I understand the volume/pressure thing now, it's the same as with water pumps and dredges, just switching air for water essentially.

Yeah let me know on your old machine for sure. If nothing else grab some photos of it, I'd definitely like to see it. I have a friend that goes down outside Hillsboro once or twice a year and has invited me to come along a few times so I may find my way down to NM. I've run into some health issues that kept me town-ridden this year but I can drive again and I'm making some good improvement now. I have a place to run a big drywasher, just need to work on a mining plan.

I'll be away from the computer the next 2 days so won't be able to reply. Got some good food for thought to keep the gears turning in my head though in the meantime.

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We made 4 bangers-4 units fed by a vibrating hopper at ol' PESCO in the day. On treasurenet ,Gold Mining forums, under drywashing are some great pics of multi units backhoe fed also. Water cooler never do the job MUCH more cfm for yardage run and you also then have a vibrator on the feeder hopper also to keep the multiple feeds going. What a massive dust cloud though and masks mandatory to prevent Desert Fever. Keep the backhoe hp down and you can escape hastles from the BLM /FS also. I don't know of a single mfg who makes them anymore commercially. Too bad as water grabs are killing off wet work so dry makes more sense than ever,but noise,filth and such NO fun-John

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