2021....

[Moneybox]

Sunday today so I needed a nice quiet job so as not to disturb all those neighbours who might be sleeping in. I decided to take a look at the sluice ready for when we have this dryblower up and running. Hopefully we'll have some concentrates worth putting over the dream mat before finally panning it off.

I only purchased the piece of 10" dream mat and then pressed up the main channel last week in Perth.

I can fold up little things here so I thought it would be a simple enough job to do the delivery box at home.

I've never made a sluice because for these you need water, something we don't see much of.

I think I'd have done a better job with a perforated plastic pipe but I find it easier to work with metal and I had this piece of an old trampoline that was left over from building the pond ladder.

The 17,000L submersible pump delivered water ok but the retainer they supply for the dream mat sends the water flying.

I made a much longer retainer out of a thin bit of stainless steel and got rid of the jump-up that was sending the water flying.

I put some little vanes into the water flow to try to direct it more to the back of the box instead of it all rushing to the end of the tube and then swirling about in the box.

Then I put a bit of a restrictor in the outlet of the box to try to steady the velocity of the water.

The main problem seems to be way too much speed in the flow of the water.

There's really not very much depth to the flow so nowhere near the one or two inches of depth suggested in the notes I've read. That depth of flow might be achievable in a gently flowing creek but the pump creates a very fast flow so I don't know if it's going to work. It settles down a bit near the bottom of the sluice but it's still passing over the mat very rapidly and quite shallow. The slope at present is right on 10 and when you have one size of chair that's really hard to change

 

[Davent]

Shes all coming together!

 

[silver]

You could put in an overflow so only the water you want goes over the mat... the rest just bypasses underneath maybe.

 

[Moneybox]

You could put in an overflow so only the water you want goes over the mat... the rest just bypasses underneath maybe.

Silver they say that I need and inch or two of depth over the mat so I can't afford to lose water. The only way I can see to do that is to lay it down nearly flat.

 

[Simmo]

Hmmm?!
Silvers Idea has merit, but I don't really understand your operation??

With our big plant we had a big valve that would divert the water to waste when doing clean up, so you didn't have to rev down the main pump??
But that being said, we could somewhat 'afford' losing the water as being pumped from the dam.... You dont have that 'luxury'?

A launder flat is no good?

 

[Moneybox]

Hmmm?!
Silvers Idea has merit, but I don't really understand your operation??

With our big plant we had a big valve that would divert the water to waste when doing clean up, so you didn't have to rev down the main pump??
But that being said, we could somewhat 'afford' losing the water as being pumped from the dam.... You dont have that 'luxury'?

A launder flat is no good?

The sluice is only to further reduce the concentrates from the dryblower. It should cut panning to a minimum.

A launder flat??

 

[Nightjar]

MB,
Don't understand why you have to have that depth of flow over your mat.
And agree with Simmo, not to lay your mat on a lesser angle, "launder flat.'

 

[Moneybox]

I think it would work better if I could just use the pump to return the water and have a gravity feed into the sluice.

 

[Moneybox]

MB,
Don't understand why you have to have that depth of flow over your mat.
And agree with Simmo, not to lay your mat on a lesser angle, "launder flat.'

Peter I'm only going with advice from youtube and this site. I've never used a sluice.

 

[Moneybox]

MB,
Don't understand why you have to have that depth of flow over your mat.
And agree with Simmo, not to lay your mat on a lesser angle, "launder flat.'

Peter I'm only going with advice from youtube and this site. I've never used a sluice.

https://www.prospectingaustralia.com/forum/viewtopic.php?id=24560

 

[silver]

I think it would work better if I could just use the pump to return the water and have a gravity feed into the sluice.

Header tank with overflow return

 

[Tathradj]

Flap of rubber that rides on top of the water fix's that issue.

Further more play with the sluice angle and water flow rate.

 

[Muk]

Try a baffle in your header box so the water has to build up and flow over it before exiting the box into the sluice I use that system and it works a treat cheers all the best Muk.

 

[Goldtalk Leonora]

maybe just run some dirt and play with it. You won't loose any gold as it's a closed circuit.

 

[Moneybox]

maybe just run some dirt and play with it. You won't loose any gold as it's a closed circuit.

Yeah now we're getting down to it....I'll run some dirt

 

[silver]

If ya gunna post pictures then ya should salt that dirt with some big chunky nuggs (keep a tally so ya know ya've not lost anything though)

 

[Dihusky]

Getting the mat to work at its optimum is a balancing act between water volume, water velocity and sluice angle so you need to be able to control each of the three variables. The mats often use little more than a 1000 - 1500lpm bilge pump and the water depth and velocity over the mat is altered by the sluice angle, with the right settings 80% of your capture will be at the top 10% of the mat.

Maybe get rid of the teeth and place a piece of flat instead with some slots so you can vary the height of the opening, this will produce a flat water flow closer to what you'll find when setting up a sluice in a stream. I seem to vaguely remember seeing a suggestion that the sluice angle should be around 7 degrees give or take.

 

[Moneybox]

Getting the mat to work at its optimum is a balancing act between water volume, water velocity and sluice angle so you need to be able to control each of the three variables. The mats often use little more than a 1000 - 1500lpm bilge pump and the water depth and velocity over the mat is altered by the sluice angle, with the right settings 80% of your capture will be at the top 10% of the mat.

Maybe get rid of the teeth and place a piece of flat instead with some slots so you can vary the height of the opening, this will produce a flat water flow closer to what you'll find when setting up a sluice in a stream. I seem to vaguely remember seeing a suggestion that the sluice angle should be around 7 degrees give or take.

Thanks Dihusky, I put one bucket of dirt through and was a bit disappointed to not see any colour :/ however it was only one bucket of dirt chosen at random. I've got four more buckets chosen at random from across the lease. Perhaps I'm being a little optimistic expecting something from a bucket of dirt but it would be nice and it would help guide me to the best spot to start the dryblower.

Mrs M said she'd come and give me a hand collect the dirt but I noticed the SDC slung from her shoulder :lol:

I like Muk's suggestion of a baffle to steady the flow and I think Tathradj idea of a light flap of rubber has merit as well. Anyway I'd better get back to work because we've got a cooler day and I'm still trying to get this dryblower setup. I'm just finishing off the welding on the conveyor frame so Mrs M can paint it. It's all light tube so I think spray painting with the breeze will be a waste of paint. It looks like a paint brush job. I'll post some photos later, too busy now.

 

[Mackka]

Go you good thing. I am loving this so dont keep us In suspenders Moneybox.
Mackka

 

[Nightjar]

MB, Throw a number of tiny lead snips in with the paydirt. When your set up recovers all these you will know you have the ultimate angle, water flow & velocity.
Approximate angles;
Dry blower = 21
Sluice = 10