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Hello there, New member from Alaska on here but I have been reading this forum on and off for a few years now. Recently I have acquired a 42 inch diameter pipe with a wall thickness of 3/8" and its 12 foot long. There is only one small dent in it, no where near where the rollers will be. I have a few questions on the screen section, to keep costs down id like to only buy one 48"x120" punch plate section, which gives me approximately 46 inches of useable screen area, minus the 3 sections that will be left in the pipe which will be about 5-6 inches wide. I am worried that 46 inches of screen will not fully clean and get all of the fines classified down into the catch pan. When I drew a sketch up, it looks like I can put another 12 to 16 inches of screen ahead of that section, and not interfere with the rollers. But then I would have to find another piece of punch plate to use. Also, kind of stumped on what angle to build the barrel into, I've read anywhere from 1/2 and inch per foot all the way to 1.25 inches per foot like on the steeper NZ plants. I was thinking 3/4 of an inch per foot should give me the proper angle to start with, not be too steep, but not to shallow to where it causes my material to roll all day in there. I plan on reinforcing the barrel in multiple places to avoid flex and bending, due to the thin 3/8" wall. Another hurdle I found is the sprocket, id like to stick with roller chain, but can not find anyone who has a 46-48 inch sprocket they can order. I've read about and seen the plasma table and water jet cut sprockets, and heard they don't wear well, and chew up the rollers. Am I to optimistic to think I can run 40-50 yards/hour  through this size barrel? Any input and advice will be appreciated, Thanks.

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use shaker screen for screen section,the angle depends on your material we run ours about 3/4 inch per foot we drive ours with chain with bolts threw the barrel for the gear ours is 42inch fed with an conveyor it will easly run 50yards per hr.

flatter angle for more clay in material, steeper for better gravel our screen is 4ft wide

:) doug

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Like Doug pointed out.

 

Check around at several of the gravel plants and ask about buying a couple three of the damaged screens taken off their shaker.

Once the screens develop some holes, they get tossed aside. The gravel contracts are usually pretty specific about the amount of over-size allowable.

With a few of these damaged screens, you can cobber up enough usable area to make a nice trommel.

 

eric

 

-------------------

Edited to add:

 

I am a bit curious when it comes to the "to keep costs down" and then the desire to run 40-50 yards an hour.

Washing and classifying just aren't the operations to be cutting corners on.

Been usually to my misfortune every time I tried to push my cost containment too low.

Oh and there is that matter of tails to be dealt with. Move the plant or move the tails. Sooner or later gotta deal with them tails as part of rehab.

But then again, I've never worked any operation that ran more than 2-4yph.

 

eric

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First consideration is capacity. If it's a 40 to 50 cubic yard per hour spec --> design for a 60 cubic yard per hour trommel.

 

At 60 cubic yards per hour, you are assumed to be "Feeding" 60 yards per hour.

 

It doesn't ALL go through the screen. So have you done a "particle size analysis"?

 

If the answer is "No", then you need to determine "how much" of "what size" will pass the trommel screen.

 

- Geowizard

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Thanks for all the advice, The costs I want to save is just the original mfg costs, a sheet of the punch plate sets me back about 2300$. That's more than all the steel for the frame will cost. As I said I'll be able to come back and add 12-16 inches of screen ahead of the 46 inches, to help out. The material I'm planning on running is mainly river cobble, with lots of heavy sands and smaller pebbles, I plan on classifying to 5 inch minus through a grizzly either on the hopper or on a feed conveyor. There's no hard shale or sharp bedrock boulders where I plan on using this, but I still intend the build it tough. I have another question, My hopper design so far is the NZ trommel style, But I will be using 1/2 plate, on a 3/5 angle, with an opening at the top of 5'x5'. Is the 3/5 angle going to be steep enough? There will be a spray bar setup in the hopper to help wash down the material, and I will be lining it with some spare UMHW sheets I have around, which are 3/8" thick. Worried that the sharper rocks will stick, and have trouble smoothly feeding down into the trommel. My drive system Im still figuring out, I would like to stick with a gas/diesel engine powering a hydraulic setup, as I can get parts fairly easily, where as an electric gear motor setup I would have to order parts and wait 2 weeks for them to get here at great expense. I don't believe I will be able to just stick the sprocket right on the hydraulic motor, so should I use a worm drive reducer, or just a 2 chain double reduction setup? I already have one of the sluiceboxes I will need, its 24 inches wide, and 12 foot run. Built it for a customer who put a down payment on it, he gave me an old one to copy off of, but he didn't want it anymore, due to his health he wouldn't be able to mine anymore. I have read all the riffle studies and visited a few mines, all which had shaker plants, and as far as the rule of thumbs I've been told is 5-8 yards per foot of useable width per hour with about 150 gallons a minute a foot.  Im already planning on making another box, to set them side by side, But should I incorporate an angle iron riffle section right before these? Sorry for the wall of questions, this is my first trommel build, I've built many high bankers, and build freight sleds and sleighs for snowmachines. I do a lot of fab work, and have a full shop, and know that's its easier to build stuff once and listen to advice from people in the know. Thanks.

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we run our trommel with a 15 hp gas motor double chain reduction. shaker screen 1inch shaker screen works better than punch plate , lasts forever if you need to change size $300 will probley do it also it cleans out better than punch plate, 45inch opening around the barrel  grizzley on hopper is 5inch, sluice is 24 inch wide 8ft long, lots of water we run 2-3inch pumps, spray bar full length of barrel

with spray bar in dump hopper, most of the gold is in the 1st 2 foot of the sluice in the angle iron riffles then expanded metal riffles all with minners moss under it all. the gold caught is from flee sh## to nuggets to 3/4 oz. our barrel is and old propane tank

for free

 

 barrel is 42in x 18 foot we have app 6000.00 in total cost (iron , motor gears , shafts , chain , wheels , screen , sluice , mats , welding rod , torch gas , grinding wheels , misc.  ect.) not time we built it ourselves

thanks doug :)       im in Alaska running gravel in the central area cobbles down to fines old creek bed benches

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Weeder...

  Good luck on the project!  My trommel is a piece of 48" pipeline pipe. I use 1" woven wire screen in the screening section.

 I chose not to use punch plate. It is heavy and the surface to open space is far less than with wire screen.

 How many yards you can put through a 42" drum really depends on your material, the screen type and the opening in your

screen. In typical material with about 50% of the bank run being minus 1" mesh I have no problem getting 50 yd/hr through

my 48" drum with a 5' screen section.

 As for the sprocket .... having sections cut from stock works fine. If it is wearing on the chain rollers it is more likely a bad placement/

alignment issue. You do not need a continuous sprocket around the drum. Spaced segments works fine.

 I'll try and post some photos of my trommel build for you.

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hello all.  been reading your forum for some time and now have a question but weeder57 seems to have the same issue as i.

my barrel is 12ft long and 42 inch diameter but only 1/4 inch thick.  I was hoping sir chickenminer could post some pics of his segmented sprockets for chain drive and maybe some info on how he obtained them.  no way I can afford to have a full diameter sprocket custom built right now.  so any pics and details would be awesome.  of course when u have time.   ill be using my washplant in the desert near Stanton Arizona in the sonoran desert.  obviously have to recirculate.  thx for a great informative site.

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Oh man...

 Sorry guys I forgot all about this thread! Just too busy.

 

Here is a photo of when I was rebuilding my trommel

 trommel%20rebuild.jpg

 

 Here is a closer photo of the sprocket segments around the drum. I'm using #160 roller chain. Segments were cut from plate steel.

 

trommel%20sprocket.jpg

 

 Any questions just ask. I'll try and be better about answering.

I have about 20 close up photos on the trommel, but it would make for a huge thread.

 Any photo in particular let me know.

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wow great pics and thank you very much.

 

ill list the questions I have and try to make it short lol.  I know your busy.

 

1. are you running this op by yourself

 

2. how on earth did you cut those sprocket segments?  ive got a small handheld plasma cutter but doubt I can cut that right unless it doesn't have to be spot on.

 

3. what is the thickness of those segments?  im going to try to use 100h chain

 

4. do you recommend o ring chain?

 

5. do you use a grizzly or run it all?

 

6. would love a shot of your water entering your hopper set up, when you get a chance

 

7. is your barrel screen mesh the "welded" woven mesh type?

 

8. are you using a type of gear reduction?  im going to use my Honda 9hp motor that has a built in 6 to 1 gear reduction that I hope will keep my rpms slow enough without pillow blocks and jack shaft type setup.  it runs max 3600rpm.  going to rig up a cheap belt to test the rpm when I get my casters set and barrel on.

 

9. well that's all I can think of so far lolol.  no hurry, and thanx again for the pics and info.  saving me a lot of trial and error, and maybe some other folks too.

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ill list the questions I have and try to make it short lol.  I know your busy.

 

1. are you running this op by yourself?

   Yes

 

2. how on earth did you cut those sprocket segments?  ive got a small handheld plasma cutter but doubt I can cut that right unless it doesn't have to be spot on.

   I didn't !  That's a job to farm out to someone with the correct tools.

 

3. what is the thickness of those segments?  im going to try to use 100h chain.

  I believe it was 1" plate

 

4. do you recommend o ring chain?

   Personal choice. My #160 chain is not o-ring chain and I'm still using the same chain after 20+ yrs

 

5. do you use a grizzly or run it all?

   No grizzly. Everything goes into the hopper, but you better have a stout built system!

 

6. would love a shot of your water entering your hopper set up, when you get a chance.

   Okay... here is looking up the trommel drum

 trommel%20spraybar.jpg

 Here is looking up the hopper from inside the drum at my main spraybar.

trommel%20hopperinside.jpg

7. is your barrel screen mesh the "welded" woven mesh type?

  Not welded.  I order the heaviest wire size available in 1" mesh. I forget exactly but it's like 3/8" wire they use.

  A screen usually lasts me 5 seasons.

 

8. are you using a type of gear reduction?  im going to use my Honda 9hp motor that has a built in 6 to 1 gear reduction that I hope will keep my rpms slow enough without pillow blocks and jack shaft type setup.  it runs max 3600rpm.  going to rig up a cheap belt to test the rpm when I get my casters set and barrel on.

    Yes I use a heavy gear reducer. My plant is powered by a small diesel engine turning 1800 RPM. I believe the gear reducer is 20:1

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if you use the punch plate, take a close look at it and mark the side that has the holes slighty larger from the punch, that will be the outside of the plate when the fab shop rolls it for you.

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