Wishful thinking....or....Bunnings sluice failure

Prospecting Australia

Help Support Prospecting Australia:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.
Wally69

Wally69

Paul
Joined
Dec 13, 2013
Messages
3,539
Reaction score
9,361
Location
Sydney
A question for those hydraulics and sluice experts.......

After running a bucket of dirt through my Bunnings sluice, quite quickly and with just a little soak of the rough with no classifying as most gravel was less than 7mm, the sluice capture is on the left and pan capture of my spoil on the right after sieving a well puddled slop to minus 2mm.

Has my sluice failed or is this sort of loss reasonable?

1445744250_image.jpg
 
Riffles may be slightly clogging up with junk rather than gold. Could be feed rate..water flow..

It looks like chunky type gold that its dropped, I'd probably work on something to lessen that loss.
 
On a home made sluice, or should I say on a quick build sluice without much testing that what you recovered is a good amount.

Anything over 80 percent capture is acceptable and I generally try to get to around 85-90 percent capture rate.

You will never catch it all regardless of what anyone says.
 
Reeks said:
What angle were you running it on Wally?
Water flow from ?
What matts you running?
Click to expand...

A picture probably works better Reeks, I ran a bit more angle this time to clear the stone and reduce the concentrate buildup, last time I had it a a bit too shallow. 30l/min is the pump rating.

Also tried a ski jump this time to get a bit of turbulence midway to bounce the gravels around a bit. Was thinking it could do with another one. Although a coarse black matting section might be the go.
1445751457_image.jpg

1445751563_image.jpg
 
From what I can see from your picture and the bunnings gutter.. to me having cuved sides where the mesh is would be making side vortexes which have the opportunity to disrupt the central vortexes where your meah is. If you have a spare bit, try running the mesh on the bottom only.

That mesh to me is wrong creating the wrong vortexes you need
 
I haven't used mine with a bilge pump wally so I can't really say if it's that but I can say I run a lot less angle than what you have in the pic.
Try less angle, more water and see how that "pans out"
;)
 
Slick plate. Uninterrupted water flow. Proper angle. All which you may have to experiment with in custom size. Gold is pretty forgiving though. Maybe capture tailings and pan out worst case scenario. Bets panning the lot.

Grab a few handfuls of pellet shot paint them an obvious colour (fluro) and run. You will work it out pretty quickly.
 
Thanks guys for the tips and ideas

The fly poo sized bit that passed through to the keeper was disappointing, it could have been in a clay ball or bounced through when my feed rate was too heavy.

I don't think I'll stop tinkering until I get better capture, a set of adjustable legs and classifying box/screen are now on the to-do list.
 
G'day Wally.

1445811686_meander.gif


The above diagram shows stream dynamics with a straight section of creek (similar to your bunnings sluice). the three smaller diagrams to the right show flow dynamics, indicating where the transporting flow is strongest, which has the highest velocity.

The lighter coloured part of the stream, or creek, is where the transported sediment (read as gold) drops out.

By having obstructions (mesh) bank to bank, you have created all areas in your sluice as being turbulent, reducing the capacity for gold to drop out and be trapped.

I reckon that AtomRat is on the money when he says the mesh is creating the wrong vortexes.
 
Wally....I've tried something similar to your setup before as a small backpack river sluice.....I also found a bit of loss occurring.

....but I did find a fix that worked quite well.

The issue is the high flow/pressure area of the sluice is straight down the centre....the same place all your gravels and gold will want to travel because of the cupped shape (think gravity). Putting a few V shaped barriers down the centre (1-2cm's high) will give you an interruption to flow and low pressure areas. The V shape also doesn't chock up with crap too much. I suppose I'm saying think natural....where do you find gold in straight section of stream.....behind rocks and obstructions right???
 

Similar threads

U
Feeding sluice
Replies
5
Views
2K
mudgee hunter
M
Thumper
Chapel Hill alluvium (SA)
Replies
7
Views
4K
Thumper
Thumper
M
Back after a break from PA with a tale to tell...
2
Replies
26
Views
9K
Goldtalk Leonora
G
grippsy25
My Bunnings Sluice Design
Replies
9
Views
7K
Ryan J
R
TenOunce Tone
Check conglomerate for gold!
Replies
10
Views
10K
TenOunce Tone
TenOunce Tone

Latest posts

Top