riffle setup with expanded metal

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Hi Everyone hope you all are good and well
I am setting up my new sluice and have a question regarding the riffle height vs the expanded and matting height (bunnings blue un-backed spaghetti mat) i have done a fair bit of reading/searching but have confused myself more than anything i think,
The expanded and matting come to 20mm +/- a mm or two, i am putting a couple of modified Hungarian riffles before the expanded, what i am not too sure about is the height of the riffles, should i have them set at the same height as the expanded and matting?, or is there a better idea that i am not seeing, i am only having the v mat under the riffles (v mat goes the full length of the riffles and expanded/bunnings mat)
If i haven't explained it clear enough please let me know

thanks guys and happy hunting
Jamie
 
still have to cut the expanded and havent got the v mat in here but its the basic sluice, i have done a bit more since these photos, proper legs and mounted the hopper box
1424917955_img_0173.jpg
1424917979_img_0172.jpg

the sluice is 250mm wide, 1100mm long
 
my 2 cents ....Try to leave a bit of "nothing" at the top of the sluice, and I would be trying to keep the riffles small if u even need them at all. An alternative would be no riffles and just one bracket that holds the expanded down at the top end of the sluice....ie 25cm of nothing, then a screw down plate to hold the mesh/carpet in place. The plate kind of acts as one little riffle. I find the gold will mostly be found at the base of that little riffle/bracket.

1424936904_hb1a.jpg


No riffles here and she catches gold just fine! Usually almost no gold in the bread crate section
 
thanks mate, i have left about 350mm (if remembering correctly) of nothing/slick plate, my brackets to hold the expanded down are mounted to the side and pivot from a point forward of the riffle/ expanded starting point and clamp at the rear end of the sluice, i am putting a joining piece to hold the leading edge of the expanded that will also hold the leading edge of the v mat, so with that in mind i will get it similar to yours i think and see how we go, thank you for the help
 
Hi jamie another alternative is to place a vmatt in the first 350mm.with 9mm or so expanded on top.this can be removed and checked periodically to see how you are going.not pimarily as a catchment area but to hold back the heavies a bit until the lighter material clears out.leaving less material in the mesh riffles lower down so the heavies have somewhere to drop out.you will find that alot of gold will drop in the fist section and not migrate down your highbanker very far at all.you can also decrease in mesh size as you go down the the banker.this will be classified in your matt to the differing size mesh you have.cut the moss into 3 pieces and you can check the percentage of migration you are getting.so you can make changes if need be.something like 9mm in the first bit 19mm in the second more 9mm And 5mm down the bottom.lots of different idea's all catch gold .you just need to pick what suits you best.
 
The slickplate area and angle also increase water/material velocity the longer the area the faster the material will move as it travels along.A slickplate won't catch gold.but if you have something there like in the banker pics above,just a piece of mesh it will catch some gold.but by having something like i suggested you have increased your catchment area by 350mm In length.rather than the length of your hopper and slickplate area merely classifing material through the grizzly and increasing velocity. Material will be stratified whether you have a slickplate or matting under your hopper.so many variations of methods of catchment available nowadays it's great but time consuming testing.good luck
 
Thanks Ausniper, So many variables that will work i suppose, just a matter of trying it out and going from there, i have plenty of material to change it about and go with what is best for my sluice and dirt going into it
 
jamie said:
thanks mate, i have left about 350mm (if remembering correctly) of nothing/slick plate, my brackets to hold the expanded down are mounted to the side and pivot from a point forward of the riffle/ expanded starting point and clamp at the rear end of the sluice, i am putting a joining piece to hold the leading edge of the expanded that will also hold the leading edge of the v mat, so with that in mind i will get it similar to yours i think and see how we go, thank you for the help

I've read one of those 100+ pages of sluice theory and he seemed to indicate the nothing/slick plate section was prob more successful than any matting...the aluminium and the gold had a very good relationship. Kind of like the "light" material bounces like a tennis ball, while the gold bounces like a piece of lead....ie it sticks to the aluminium and slides straight into your first trap. I like the theory and my banker seems to prove that for me in the field. I'm not loosing gold, just make sure its not sliding under the mat!

I think that the liquification of your material is paramount, physics seems to do the rest pretty well. I reckon I could use paddle pop sticks as riffles and they would catch the gold....if you know what I mean. :lol:
 
i believe that is why i am confused and unsure what way to go with it or if matching riffle height to the expanded/mat is as critical as i thought, i have read a lot of sluice tests and theory papers now and all seem to be similar but with differing opinions on the most efficient set ups, that's why i ask here cause i seem to trust the guys here more than anything
 
I go with Wal's tried and tested - nothing under the expanded, nothing on the slick plate to inhibit flow/liquifaction/seperation. Works for me. The size of your expanded might create different conditions to what Wal has engineered though - I can see how a riffle or two might be necessary on that really fine expanded I have seen people running.
 
http://youtu.be/-kp8Jgsluds

Here is a link to a goldirocs highbanker a bit different down the bottom section with all the riffles.but the top section under the hopper runs a perforated punch plate with removable tray and vmatt and it works well.there are other vids that show the gold caught right under the hopper as well.the old timers used timber and caught gold not all of it but alot.no one setup will work everywhere.that's half the fun, test and tune .if gold stuck to aluminum we wouldn't need matts would we?as long as there is gravity the heavies will head for the bottom.
 
http://youtu.be/KMnVQVQGUc8

Here's another vid if you can watch for 10 minutes .there are some good statistics towards the end.expanded thats pretty heavy with gold.but if you're half setup,finish it and test it and see. You might be happy with what you got.i hope i didn't make it to confusing 8) :cool:
 
ausniper said:
http://youtu.be/-kp8Jgsluds

Here is a link to a goldirocs highbanker a bit different down the bottom section with all the riffles.but the top section under the hopper runs a perforated punch plate with removable tray and vmatt and it works well.there are other vids that show the gold caught right under the hopper as well.the old timers used timber and caught gold not all of it but alot.no one setup will work everywhere.that's half the fun, test and tune .if gold stuck to aluminum we wouldn't need matts would we?as long as there is gravity the heavies will head for the bottom.

Correct, lots of different set ups that all seem to work so I think the lesson here is, paretos 80/20 rule........in that if im catching 80%+ of the gold, to spend too much time on different set ups for different types of gold, well leave that to the next 20 years as you work out which system is best for you. Given that we haven't come up with a number 1 set up to catch all gold no matter how small plus in all circumstances with say lots of clay, or massive rocks etc.....your set up is as good as anyone elses....until you refine it for the specific areas that you high-bank in.
 
Great advice twapster.Jamie your hungarian riffles might work great where you are, level with the mesh would be a starting point.the best advice might be build it however you like.if you spend time running gravel you will see that there is alot more to it than riffles.Water speed ,angle,type of grizzly and hopper,material,black sand ,white sand,lots of clay,no clay,how much time you have,whether you are by yourself,how far from water source you are etc .Doc from goldhog just uses matting and has done extensive testing with perspex sluice boxes.Doc just made a mat that he says replaces miners moss.The gold machine and goldirocs video do it for a living right now.not really hobbiests.but they get the gold ...........alot.good luck.
 
thanks heaps guys, i will mainly be at oallen ford, so very loose sandy soil with a lot of river stones mixed in to it, really appreciate the help and advice you all offer up so freely, it is that that makes PA the best forum, i will build it and show all how i go and mod from there if needs call for it, when i take it for its maiden dig will let every one know so those that may be around the area can come for a chat, a beer and might even put some dirt in the sluice lol
Cheers
Jamie
 
ausniper said:
Great advice twapster.Jamie your hungarian riffles might work great where you are, level with the mesh would be a starting point.the best advice might be build it however you like.if you spend time running gravel you will see that there is alot more to it than riffles.Water speed ,angle,type of grizzly and hopper,material,black sand ,white sand,lots of clay,no clay,how much time you have,whether you are by yourself,how far from water source you are etc .Doc from goldhog just uses matting and has done extensive testing with perspex sluice boxes.Doc just made a mat that he says replaces miners moss.The gold machine and goldirocs video do it for a living right now.not really hobbiests.but they get the gold ...........alot.good luck.

Hey Ausniper, the one thing that I don't get is the highbanker hopper set ups i've seen with the Gold Hog. Seems everything else is fine but how do you shovel and classify with massive PVC pipe right where you want to throw your payload?

Frustrated the hell out of me when I used one, I often throw brick+ size rocks into my banker that are covered in clay, if I did that with some of the Gold Hogs, id have busted the water pipes ten times over. And then the pipe is in the way when you want to remove the overburden from the classifier? Weirdest set up ive seen yet the bottom part of the sluice looks nice. Not sure if anyone else has noticed this issue but certainly bugged me for the day I used one?
 

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