Building a large capacity High-banker - Instructional video

[Gold miner]

Hey Jono,
I know you are asking Wal, but if I may put my two bobs worth in????

See how that walkway mesh is vertical in respect to the waterflow?

What riffles are all about, is creating a high pressure point in the water flow at the front of the riffle, then as the water falls over the top of the riffle, a low pressure point occurs. Gold has high specific gravity, so should fall behind that riffle, where there is little pressure to keep the gold moving.
Then a good mat (moss) should hold that piece there, when further heavies, not necessarily gold, come along and try to displace it. (displacement theory).

Many people believe that the gold gets 'stopped' at the front on the riffle, that is not true.

Now I am not saying that your riffles wont work, no way... but you will be prone to everything in that launder stopping behind a vertical surface, clogging up, and then you will have no riffles, gold over the end...

My opinion mate, dont wanna pee on your fire!!
Wal might have a totally differant view, then you can make your own mind up!

Cheers,
GM

 

[WalnLiz]

Hi Jono, GM is absolutely right in his description of how a riffle system works, and the pressure ratio created by the water going over the riffle.It's the vortex created by the riffle combined with the water speed and riffle height to length ratio that has to be taken into account.

Firstly lets look at the riffle height to length (width apart) ratio. I have played around with these for many years and found that the optimum equation is a 1 to 4 ratio. That's 1cm high to 4cm apart. If you keep to this ratio combined with appropriate water speed you will find your riffles should not clog.

Now lets look at vortexes...A vertical riffle and a 45deg riffle will both create a vortex. A vertical riffle will create a slower high rolling vortex and a 45deg riffle will create a lower faster flowing vortex. We need to look closely at this relationship when trapping fine gold in a short distance. The faster the water flow the faster fine gold travels down the box ...the longer the sluice needs to be.

The best scenario for trapping fine gold is the slowest water speed to keep the mat from clogging. A vertical riffle will slow water speed quicker than a 45deg riffle.This is also why large dams use vertical blocks to slow spillway flows.

Getting back to your mesh Jono....2cm high x 4cm apart has the wrong ratio to be able to be cleared adequately and clogging would be a real possibility. I use the 1cm x 4cm mesh and have never had a clogged sluice. I have checked the end of my sluice many times over the years and am confident no gold gets through. I'm aware that the norm is a sloped riffle in the lazy L config and am happy to test their box against mine any day on the stream. I use to run the conventional riffle arrangement until i experimented with sapphires and was soon convinced of the advantages of a vertical riffle.

My suggestion Jono is try running both on a short sluice with fast water flow and choose for yourself. Make sure you use a coarse woven rubber mat and not carpet. And if you chase sapphires with a 45deg mesh make sure you put a bucket at the back to collect all the sapphires that will definately go through.....Cheers Wal.

 

[Ozjono]

Ok thanks for the reply gm and wal I thought it maybe a bit tall is always good to ask I do have 45 deg riffles I just would like to try and catch sapphires as well

 

[WalnLiz]

Hey Jono,...PM me the width of your box and the length you require and I can cut and send a piece to you. I have plenty spare and that way you can compare the meshes for yourself....Cheers Wal.

 

[WalnLiz]

Hey guys,

Sorry if this post is out of place but I am pretty new to the rules of forums etc
I am looking to build a highbanker/sluice very similar to the one in your video WalnLiz. (Your videos are absolutely brilliant I might add, extremely informative, well shot etc etc the list goes on honestly

My question is are there any plans available or could you point me in the right direction please?

Also as someone that has stumbled across this information through researching the internet I believe, if you were so inclined you could sell the plans as a digital download...(if you do not already)

Again I apologise if this is in the wrong thread etc and I will happily take any instruction/criticism

Thanks

Tim

Thanks for the post Tim....As soon as you have made 10 posts on the forum you will enable the PM function. When you have done this just send me a PM and I can give you all the dimensions and advice you need to get your hi-banker on the way. To get the 10 posts up just ask a few questions on hi-banking and answer the responses. won't take long to get the 10 posts up.... Cheers Wal.

 

[Gold miner]

My suggestion Jono is try running both on a short sluice with fast water flow and choose for yourself. Make sure you use a coarse woven rubber mat and not carpet. And if you chase sapphires with a 45deg mesh make sure you put a bucket at the back to collect all the sapphires that will definately go through.....Cheers Wal.

Hehe, Wal I have been thinking of a polite reply all day!!!

Jono,
Let Wal and I agree to disagree on riffle design/usage...

However mate, let me tell you that lives have been lost on the fields when someone thought, or did have, a better riffle design than others....

From personal experience, just lately, and Palmer Digger can testify to this...., a 'miner' came up to the Palmer, with a new design....
This design, according to the 'engineer'/'builder' was infallible and would retrieve the finest of gold....
I was intrigued.....had to take a look....
I thought straight away that although the system they put together, would trap the Au, it would not be able to take volume'...and thats what boosts the bank account...more tonnes thru the plant....
A few weeks into operation and the company is going thru a major restructure so I hear.... The 'new' riffles, the 'new' plant didnt work.....

OK, on with the riffles, sapphires have a SG of 4, Gold 19..... Putting 'vertical' riffles in, you will, with correct angle and flow, no worries, catch these little buggers!

But guess what? Quartz, and lots of other worthless crap like diamonds have a specific gravity around the same...
However, by 'targeting' lower SG minerals/gems you are prone to clogging up your launder with this lower SG 'crap', (like diamonds etc) and giving higher SG stuff no where to go....'cept over the end...

So I believe, the riffles need to be angled and you will get the gold, but perhaps lose crap like sapphires and diamonds..... :8

There is a theory called 'displacement theory' and that is where an item of higher SG will displace another item of lower SG until it itself is displaced by another item of higher SG.... think about that theory....it will help you in all aspects of prospecting...

 

[WalnLiz]

Ahhh... the agree to disagree scenario continues GM..mate .Where i do agree with you is that in a perfect riffle world where "gold" was the only collectable, then a sloped riffle with a long sluice...be it raised or dropped together with a predetermined water flow / speed would be the scientific way to go. HOWEVER...in agreeing with that principal..and having worked with mechanical jig separation plants on tin and sapphires, I'm a strong believer in the advantages of vertical riffles where both gold / sapphires /zircons /spinel.. IE.. specific gravity separation is involved.

Now lets talk about specific gravity of the above gems...all are over 4 and quartz (which you mention is about the same).. is in fact only 1/2 the SG. ..Gold with a SG of 19... if kept in suspension will not get displaced by quartz or even high specific gravity gems.....Now suspension is the key here.

Keeping material in suspension with high water flows will inevitably cause lighter gold particles to travel with the higher SG material such as iron stone and black sands..and take longer distance to fall out. This is where the commercial sluice has a disadvantage to a Hi-banker (with slower water speeds and lesser input.)

Lets get back to Hi-bankers ..If a Hi-banker is set up with flexible legs so as to act partly as a rocker box in use, then the principals involved with mechanical jigs together with lower water pressures for material suspension will both clear a vertical riffle catch zone and trap all the worthless sapphires and gems as well ( sold a 5.5ct saph not long a ago for $4900 ) I'm not in any way recommending a vertical riffle in a standard fixed /rigid sluice arrangement....that is why i don't run a fixed sluice arrangement when combining gold and sapphires. In my vid you will notice we constantly rock the sluice to activate a jig arrangement.....Would love to bring my Banker up one day to give you a demo... ...Cheers Wal.

 

[kemjak57]

That would make a great video series. There is a lot of knowledge and experience between you guys and it would make for some great footage. It is interesting to read both your comments as it helps the rest of us mere earthlings learn what to look for and how gold reacts. Keep it up guys I'm starting to get the hang of it. Cheers,Rick

 

[WalnLiz]

Thanks Rick, At the end of the day both GM and myself would agree that a sloped riffle is the best arrangement for a "gold" only recovery system especially in a large scale high throughput situation like in the Palmer.(but i wouldn't tell him that ) If i was working in the Palmer on a large production "fixed" sluice i would also run sloped riffles. Where we disagree is in the gravity separation methods to extract high specific gravity materials in conjunction with the gold in a high banker situation. I have worked extensively with sapphire and tin mining mechanical jigs and these are used on large scale gravity separation all over the world. The bankers we use follow these principals in a non mechanical form (hand rocking... buries the gold deep into the matting) to achieve a similar result, that's why rocker boxes work so well.

If you chuck some gold (and i'm talking the finest gold in the world) into a tin mining mechanical jig / gravity separator you will not lose any of it. The same principals have great merit in hi-bankers and i have been using it successfully for a very long time......But it does make for some great conversation..Cheers Wal

 

[cookie]

good vid wal looks like i have to build 1 my self iv just got to find same gold first, the boss ( the misses ) wont let me spend any more money yet on finding gold lol

 

[WalnLiz]

good vid wal looks like i have to build 1 my self iv just got to find same gold first, the boss ( the misses ) wont let me spend any more money yet on finding gold lol

Hi Cookie,...recon you should get the misses involved with panning and let her get the gold fever first. Once she's hooked it's surprising just how much easier it is to convince her that she actually "needs" a high-banker. Worth a shot mate ....Cheers Wal.

 

[Creekbed]

Great gear Wal & Liz and it keeps the missus busy too


Creekbed

 

[WalnLiz]

Thanks Creekbed...Liz certainly likes the adventures and getting her hands dirty...Cheers Wal.

 

[TenOunce Tone]

Great debate and info on use a hb.

 

[jml]

Hi WalnLiz,

Enjoyed the flow of information back and forth.

What are your thoughts to the mounting of a fluid bed trap on/at the end of a high banker?

JML

 

[Gold miner]

Hey Wal...
Can I...do you mind?....

JML,
A fluid bed is sort of what is called here a boiler box...
I dont like the idea in the way I have seen them constructed.
I think, the theory has massive merits, but have never seen a system where it actually works as it should!!!

No Miner I know of up here uses one.

However, that being said.....

One miner, whom I worked for as an operator and clean up pig for a while used one....
I think it would have held hmmm 50 kgs of sand and gravel...
All released thru the bottom into tubs, and tubs, and...you get it ....for clean up..
Only 40-50% on gold was in this 'boiler box'.. the rest was where you think it would be...the top few riffles...

This fella had 10 psi jets at the bottom of his boiler box, and because he could sink his fingers into the sands, he thought it was working...
Nah, simply the amount of sand/gravel; was gonna kill this box...the gold simply went over the top, and ended up in conventional riffles..

I wanna play with this idea, as said, it has merit...

but to answer your question, nah, dont worry about it...
You are so limited with your gear as it is...

Just my opinion....

 

[WalnLiz]

Hey GM...I can't believe this,...but you took the words right out of my mouth. For a change I have to totally agree with you. Bumma. Fluid beds are just another form of gravity separators / concentrators. If you use them for cleaning up equally screened concentrates from your river sluice, then they can have some merit and actually work quite well on the fine gold. To attach them to a hi-banker with classification from micron to over 1cm would be a waste of time and i wouldn't recommend it. Using gravity separation in the form of pulsating jigs (hand rocking) has much more merit with a hi-banker. Cheers Wal.

 

[Jed]

A VERY nice bit of lightweight design & engineering Wal - would love to see it in action one day.
Cheers
Jed

 

[jml]

Hi Wal,

I am in the process of building a HB according to your design on youtube. I think I have found a source for the straight sided aluminium grate in Fyshwick. It is 13mm thick with a 35mm opening in the grate. It took sometime to find I must say.
I have been reading Gary Weishaupt's article on sluices and of particular interest are his results of testing the Clarkson riffle (angle 15 dgree set back into the flow) for fine gold recovery. Have you had any experience with these?
Also with regard to your cut out design on the bread grate why not allow the zig-zag pattern to continue further down the grid? I am trying to understand the theory behind your pattern.
And when bread grate sits on the mat do you have in such a way that it is pinching down to the base of the matting so as to 'seal' off the flow under the grate?
Sorry for all the qestions. I think I've watched you youtube a dozen times so as to fill in the gaps of my understanding.
Regards
JML
Jeff

 

[WalnLiz]

Hey Jeff...I'm just 10 minutes away from you in Mckellar. Send me a PM and I'll give you my address. Come over for a beer or cuppa and i can go through all the different styles for gold only, or combination like i use. You can see the banker set up and we can discuss what will suit your needs best.Cheers Wal