Power jet vs. suction nozzle

[Shenandoah Digger]

Interested to find out the differences between the two. I see some dredges with the power jet, and then others with the suction nozzle. Why one over the other? Thanks in advance.

 

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[rick.ther]

I use both, suction nozzle for shallow when you might raise the nozzle out of the water. If you take it out it will pick up sution quickly.
Power jet for deeper and keeping the nozzle under at all times, the slug of air stops the suction, then when you get it back the action blows through the sluice and disturbs what is in the sluice. may blow gold out!
The power jet seems to be stronger, but has it's drawbacks in shallow applications.
Hope this helps.
rick

 

[Hoser John]

Suction nozzle does have better fines retention too. There is no remix at the box like a pj and stratification within the hose helps,just like insteam. The box design and flare are your greatest assets to recovery BUT any increase in % retention is always helpful-tons a au 2 u 2-John

 

[kiwi jw]

Yep... a power jet will give you better suction than a nozzle if you were to use the same motor/pump set up. The nozzle is pushing the material from the bottom up as well as trying to maintain suction. Also the pressure hose is a lot longer from the pump down to the nozzle at the bottom where you are working & so losing a bit of pressure due to friction over that distance. The power jet is pulling material off the bottom from the top right at the entrance to your flare or header box. The pressure hose is a lot shorter from pump to power jet so not losing so much pressure over the shorter distance.
As has been said a nozzle is used more for shallow work due to the fact it can reprime itself if lifted out of the water. Where as with a power jet if you lift the hose tip out of the water you have to get that air lock out & reprime to get your suction back. A nozzle is ideal for shallow crevice work.

As Hoser John said a nozzle will be kinder to the material seperation as it travels up the hose it is sorting itself out in regards to its specific gravity & drops straight onto the classifier screen in the sluice box. So to with a power jet but when the material travels past the power jet it gets that burst of pressure that will up set the seperation that happened as it traveled up the hose. The same reason why a flare is prefered over a header box. When the material that has sorted itself in the hose on its travel from the bottom up enters the flare it is already sorted with the heavies & gold traveling slower & on the very bottom of the hose into the flare where the water velocity is reduced due to the flare & on to where they drop straight into the classifier screen & the first call of being trapped. When this already sorted material travels up the hose & hits a header box it is all mixed up again & so the sluice box has to resort it all over again.

Happy golding

Kiwi JW

 

[Hoser John]

KIWI AS IN NZ sorry can'y type for squat--had a operation-john

 

[Shenandoah Digger]

Great info and pictures everybody. I appreciate your help.

 

[kiwi jw]

G'day Hoser John, Yer mate....Kiwi as in NZ (New Zealand) Great site here. Pleasure to be part of it. Lots of interesting topics & people. Always a pleasure to share what little I know & have learnt from others & also by experiance. I am a fan of making as much of my own gear as possible. Like the little high banker above & below. We call them banjo's. This was the first time I used it with the ply board on the front to take my 2" suction nozzle hose set up. Generally I just shovel straight in to it & hook the motor/pump up to the spray bars. The gold in the pan in the above pic is the result from a couple of hours of doing that crevicing & cleaning out of the schist bedrock in the others pics from a river in Central Otago in the south island of NZ. The gold here was generally of a chunkier, coarse flat nature & not so much fine. The fine gold would have tended to be carried on further down stream in a flood. As you can see in the above pics this bedrock would be under water in a flood & the schist fingers trapping this gold in its cracks & cleverage. Below pic is close up of the schist I have blasted clean & washed out.

This is the fine gold I get from my local river in the Coromandel area of the North Island where I live from using the banjo in the above pics by shoveling in to it. This gold is what has been lost in the tailings from the hundreds of stampers that discharged their waste into the river. The Coromandel isnt known for alluvial gold but for its hard rock gold. We still have a hard rock mine working in Waihi up the road from where I live.

I live at the beach in the back ground. No 1 is the open pit which is dug down in to the old workings of the original under ground Martha Mine workings which started in the late 1870's & closed in 1952. & No 4 is a new under ground mine called Favona that is in a deep newly discovered ore zone that the old guys prospected for but got nowhere near. Although the signs showed them something was around.

Happy golding

Kiwi JW

 

[Hoser John]

thanx much for the info. fantastic lookn' bedrock--read quite a bit on au in nz--quite a bit colder water but that just forces more cool inventions-tons a au 2 u 2-john