Longer Highbanker Run

[BumbleB]

Here's one for you guys.
Is there any real advantage to increasing the length of the run on a highbanker?
If I'm running a 1200mm run, is there any advantage to adding another/second 1200mm leg to the end of the run?
I was told that most of the gold should be falling (being caught) in the first half of the 1200mm. In my limited experience (& it is very limited) this is NOT the case.
My way of thinking is that the longer the run, the more area to catch the yellow stuff- better to be safe than sorry & lose some out the end.
I realise that there are many variables (water speed, types of matting, amount being fed in, etc etc) that will impact on this question, but on face-value what do you guys think?

BB

 

[Mudguts]

Well my 2 bobs worth
My big sluice (sluice almighty) is 4.6m long and at Oallen next to no black sand makes it out and haven't found any gold in the catch pan yet
I run 2.3m of hog mat then ripples and expanded over moss on the second half
So the answer is I think bigger is better
Cheers Mud Guts

 

[HeadsUp]

It depends on how much volume of gravel you're putting through the sluice and what the gravel is comprised of , plus how effective the riffles or mesh is that you're using , plus how much water flow you run.

If there is lots of ironstone or black sand it could overwhelm the first few riffles or even the first 2 or 3 feet of sluice if you shovel it in too fast

You need enough water flow , and effective riffles that will catch the gold but also quickly clear out the dross that we don't want

Remember if your riffles are filled and not clearing out then gold will go straight over the top and spit out the end

A short sluice only a foot long can be 100% effective if it has the right water flow and not being overwhelmed with too much volume of gravel

In my case I like to shovel hard all day so I have used a sluice up to 2 metres long so I can load it up , even if the first 8 - 15 inches of riffles are filled they soon clear out and gold is caught up to 2 feet down the sluice , sometimes I get superfine gold in the last metre of mat but that's talcum powder stuff and 1-3 very small flakes ( 0.2 mm )

So in conclusion , if your riffles / mesh are working effectively with enough water flow then you don't need it . If you're going to shovel it in hard or pour full buckets of gravel in each time that could overwhelm the capture media then yes . A longer area of catch zone will improve your catch

 

[BumbleB]

Hey Mudguts, yep, thats my thinking too.
If you can have a longer run, why wouldn't you?
The only thing that worries me about my line of thinking is that it was a guy that makes the highbankers that told me that it is a waste of time- unless he is trying to do himself out of some business.........
I too am planning on switching to the Gold Hog matting. Can I ask your reasons for only running the GH mats for half your run?

 

[BumbleB]

Thanks Headsup, makes sense. Thats all those variables I suppose.
Currently running a 3700 GPH bilge pump over the 1200mm run- I intend to switch to the Gold Hog matting aswell. Doc at GH recommends that you run different profiles of the matting (they have 5 different profiles) to provide a variety of potential capture spots, depending on the types of gold you might be picking up.

 

[HeadsUp]

Thanks Headsup, makes sense. Thats all those variables I suppose.
Currently running a 3700 GPH bilge pump over the 1200mm run- I intend to switch to the Gold Hog matting aswell. Doc at GH recommends that you run different profiles of the matting (they have 5 different profiles) to provide a variety of potential capture spots, depending on the types of gold you might be picking up.

Do you know that gold hog matting requires about double the water flow rate of most other sluices ?

Check their website and forum

I looked at using their mats and would have used only 3 styles UR , bedrock and the original one whose name eludes me ATM

I don't think you will get enough flow from a bilge pump unless your sluice is under 17-20 cm width

 

[BumbleB]

Yeah Headsup, the water velocity was another issue I was giving some brain energy to. I may have to step up into a 2.5HP pump- if I go ahead I would have to muck about with it & just see. I have read in various reviews about the place that I might get away with the pump I have, but Doc on the GH site does certainly stress several times that the water speed MUST be high.
I think maybe I will just get the new matting for the current 1200mm run, see how that goes & then reassess extending the run.
Thanks for the points of view- helped me think about things a bit clearer.

 

[G0lddigg@]

I think the important thing to remember when designing your highbanker is yo create different drop zones for different types of gold. if you run longer you need areas of acceleration in between dropouts. generally the longer the box the more water required. the more water and length should increase material capacity and shorten cleanout time.

comes down to personal preference, how much equipment do yiu want to carry in each day to yo I r spot etc.

 

[HeadsUp]

Yeah Headsup, the water velocity was another issue I was giving some brain energy to. I may have to step up into a 2.5HP pump- if I go ahead I would have to muck about with it & just see. I have read in various reviews about the place that I might get away with the pump I have, but Doc on the GH site does certainly stress several times that the water speed MUST be high.
I think maybe I will just get the new matting for the current 1200mm run, see how that goes & then reassess extending the run.
Thanks for the points of view- helped me think about things a bit clearer.

I was considering making a GH sluice 12 inches wide

for that width i would need 460 litres/min

2.5 HP pump will give you only 240 litres/min on fulll revs

what width sluice were you thinking of making to suit your GH mats ?

>
one more thing if you do use GH mat is to lay out your mats so you create zones where classification can occur

visualise the slurry of gravel travelling down a surface , if its given enough distance it will self classify where gold will be at the bottom and lighter material at the top as its moving , if you have sections where you have at least 2 or 3 UR mats joined together then the gold at the bottom will have more chance of dropping in to the grooves.
there are many research papers on the topic where it was thought that too much turbulence in a sluice was counterproductive , cavitation or aeration of the mix will carry gold out of your sluice.
When you think about the above theory on classification it should tell you why people have a skid plate at the start of the highbanker sluice , that flat area right at the start of 30 - 60 cm length is your classification zone and why people often use only ribbed matting in that section with no riffles at all , or in the case of angus mckirk sluices , he uses only a very lightly ribbed pattern pressed in to the plastic , it allows self classification of the slurry , and allows the slurry to harmonise and lose air bubbles which are undesired.
with the above theory in mind it might also tell us why Mckirk sluices work well , his riffles are drop riffles that "scrape off the gold" , doing their work at the bottom of the moving slurry where other types of raised riffle create a great deal of turbulence and everything has to ride up and over the top , thats not the only part of the working action in mckirk sluices , his also get two vortexes occuring in each riffle , plus he has the catch box groove in his AU style sluices

if you want to spend a week reading there are reports below on riffled sluices , they dont study GH or mckirk style sluices but it might teach you a bit about fluid bed dynamics.

http://hecklerfabrication.com/files/sluice-build-partIII-2.pdf

http://www.scribd.com/doc/61880538/The-Clarkson-Study-Fine-Gold-Recovery

 

[Mudguts]

BumbleB
I only run half because the second stage only gets used at Oallen
Water flows are a big topic
I don't run with massive flows as people keep talking about because too much gets lost on the Oallen ford
I use UR and tight grizzlies so the rocks going down it are only the size of raisins
Just experiment with it
That's half the fun

 

[BumbleB]

Thank Headsup & Mudguts.

 

[BumbleB]

Headsup, sry mate, didnt answer your question.
I am running a 10" x 1200mm. Considering adding another 1200mm or so.
If 460lpm is wat would be required then that just about kills the idea- that's $800-900 for a new 5.5HP pump- toooo expensive for me. A 2.5HP at $400 was a nice number, but if its not enough grunt, then its not enough & would be a bit of a wasted attempt.
Might just try the new GH mats in current system & see wat happens, maybe take it from there.
Thanx agian mate, been very helpful.

 

[elrodeo]

Gold Hog excavator with extended sluice is basically 2 sluices at 36 inches long and with a few cm of overhang with Gold Hog mats.
Mat configuration that comes direct from Gold Hog runs various mat types to break up and speed up flow thus giving various drop zones.
Runs on 3000 gph pump no issue as that's what's recommended by Doc for this unit.

I rarely find any gold in the 2nd extended sluice as have the unit pretty dialed in for areas I work but can't hurt to have it there for security.
Depending if I'm hiking in or have easy access determines if I run with extended sluice or not.

Got to thank Diggerdude for putting me onto the Keene direct mount water pump as has made my Honda pump extremely portable and with the snail set up , it pumps like a demon.
http://www.keeneeng.com/Merchant2/merchant.mvc?Screen=PROD&Product_Code=P90&Category_Code=DMP

 

[G0lddigg@]

Got to thank Diggerdude for putting me onto the Keene direct mount water pump as has made my Honda pump extremely portable and with the snail set up , it pumps like a demon.
http://www.keeneeng.com/Merchant2/merchant.mvc?Screen=PROD&Product_Code=P90&Category_Code=DMP

how much did one of those snails cost for import mate?

 

[Tige]

hi bumbleb my hi banker is 30 cm top 28cm bottom ( tapered) and is 1.8m , I run a wx15 pump at about half to three quarter throttle ( 200L/min) , I use ur , razorback, scrubber matting, I run sluice at about 9 to 10 degrees to get the water speed. Water speed seems to be the key.
I was catching course to flour gold and nothing out the end.. 90% of the gold was in the first 2 feet, just hav to experiment abit.
Yes under ideal conditions pump 500+ lm at 8degrees angle would be ideal... but one has to be practical, they use some of these matting in river sluices, I don't see them having torrents of water going through them. Just have to be careful of what matting u get... good luck.

 

[elrodeo]

Got to thank Diggerdude for putting me onto the Keene direct mount water pump as has made my Honda pump extremely portable and with the snail set up , it pumps like a demon.
http://www.keeneeng.com/Merchant2/merchant.mvc?Screen=PROD&Product_Code=P90&Category_Code=DMP

how much did one of those snails cost for import mate?

I bought mine used off Diggerdude so no import cost.
At a couple of kilo max it would not be too much to post via USPS standard international post.
You pay for speed so if you can wait, jst go normal post and tracking.
I ordered up a couple of seal kits as spares and post was not that much as was not in a hurry.

Non powered sluices Gold hog recommend a combo of Scrubber, UR and Razor back mats.

 

[BumbleB]

Booya! I might be still in the game then.
Thanx Elrodeo, Golddigg & Tige- I love options! :lol:
Just as a sideline to this conversation- when I email Gold Hog (spoke to a Michael), I told them my setup & my plans to extend; he said nothing about the dire need to get a larger pump than the 3700GPH bilge that I'm running. Also, when I asked what they recommended in the way of mat configuration for my new setup, he suggested this- "I would run RiverHog with the riffle cut down, scrubber, and maybe some Razorback." & "Under the header box, put 1/4" punch plate with bolts in it to hold it about 1/2" off the mat.
Under the perf plate should be UR mat. Then start the pattern I talked about. Yes, you can finish off the sluice with UR and bedrock, but I'm not really sure it's needed in this config."
Interesting that he says that River Hog could be used- RiverHog is the commercial dredge designed matting & requires very high water velocity- granted he did say to cut the big riffle down; but interesting none the less.
Obviously there are a multitude of variables in this whole issue, & as stated by everyone, it will really require a bit of mucking about to get the perfect combo- but me tinks I'm still in the game! Suck it & see I guess!