How deep can I expect to dredge with a 2'5" ultradredge? 5 hp

[Ragnor]

I have an upgraded keen power jet dredge with the 5hp motor and air. I have a hole in the river probably 30 feet deep I would like to work in. Can I expect the dredge to have enough lift for that?

 

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[russau]

HMM the pump is going tobe the problem with this kind of depth. A 2 inch dredge is supposed to be good for only a couple of feet deep. Why not build a subie 2.5 dredge for that kinda depth?? All you would need to build would be the sluice for under water. BUT then again the 30 foot depth is a killer.

 

[Hoser John]

No way jose without a extra je/enginet and a GAST compressor as them t-80 are not much good past 16' or so. Immediately download a dive decompression table as at that depth you can easily get in trouble especially at altitude. I learned the hardway ONCE as pins and needles is ungodly pain...John

 

[kcm]

Russau has the right idea. Been through this thought process before. Came up with a design, but never had the chance to build it.

Do you have a plain, old sluice laying around somewhere? If so, you can convert that into an underwater sluice so that your system doesn't have to pump way up high. The only problem then will be the tailings piling up. ...And that's assuming your hole is ONLY 30' deep! It may be much deeper below lots of rocks and debris.

Too bad there wasn't some way to divert the waterway so you could pump out the hole and work it without diving. Oh, heaven forbid! You might damage the Earth!

 

[ratled]

If you can run a surface 2.5" then most likely you can run a 4" subbie. If you call at the right time, Keene still has some 4" blanks in one of the 2 places. You can also still find them FS in places.

ratled

 

[russau]

ratled your correct BUT he still only has a pump for the 2.5 dredge. He would have to basically get all bigger equipment. Plus a subbie hangs from under its floatation. and that could be just above the bottom of the hole to prevent and tailings build up. AND John is correct (again) about the depth and a dive chart!!! Safe beats dead everytime!

 

[Ragnor]

No way jose without a extra je/enginet and a GAST compressor as them t-80 are not much good past 16' or so. Immediately download a dive decompression table as at that depth you can easily get in trouble especially at altitude. I learned the hardway ONCE as pins and needles is ungodly pain...John

Thanks John

 

[ratled]

ratled your correct BUT he still only has a pump for the 2.5 dredge. He would have to basically get all bigger equipment. Plus a subbie hangs from under its floatation. and that could be just above the bottom of the hole to prevent and tailings build up. AND John is correct (again) about the depth and a dive chart!!! Safe beats dead everytime!

not really russau. If running a true subbie you don't have the lift requirements and the pump will work. The biggest power killer is is the breaking of the water surface and the lift above. if you run like this off a stand you probably are good to go. If you take fully underwater, and you can still run it off a stand, you need even less power. With a 5 hp motor, even with the air stealing a little power he is good to go

ratled

 

[kcm]

nor really russau. If running a true subbie you don't have the lift requirements and the pump will work. The biggest power killer is is the breaking of the water surface and the lift above. if you run like this off a stand you probably are good to go. If you take fully underwater, and you can still run it off a stand, you need even less power. With a 5 hp motor, even with the air stealing a little power he is good to go

ratled

Ratled is right.

Look at it this way - if you're out digging a hole in the ground, the deeper you go, the actual "digging" requires about the same amount of effort. However, it becomes increasingly difficult to keep raising the shovel 4', 5' 6'...until you're having to sling it out of the hole. Is the same principle here. The higher that the engine/pump have to lift all that weight (rocks AND water), the more effort it is, and the more hp it takes.

 

[winners58]

I powered my 4" sub with a 3 1/2hp and an old p100 Keene pump, I only used it 10' deep
it would sink when powered up and float back up when I cut the engine.
you may get more out of a t80 by putting a smaller pulley and a bigger reserve tank.
I have a old brown/speedy that I can pump up to 55psi and get plenty of air at 20'
my t80 that I put on my other dredge I have to pace myself.
.
you could get a second pump and use two jets or a add a suction nozzle on the end...
.

.

 

[ratled]

.
View attachment 1334093

No, you can't just put a blurb and picture and leave it at that. You have to give more info and if at all possible video! With that setup how was it for keeping it level and how was the recovery- as opposed to some kind of frame work? How was it in faster water? Inquiring minds have to know!!!

ratled

 

[mike(swWash)]

All these posts prove that a gold pan is a gateway drug to a 6" dredge

I'm up to a 2.5" and will never need anything bigger, well, maybe a 3" will be better

 

[njcommercialdiver]

Ragnor, where are you located?

 

[russau]

not really russau. If running a true subbie you don't have the lift requirements and the pump will work. The biggest power killer is is the breaking of the water surface and the lift above. if you run like this off a stand you probably are good to go. If you take fully underwater, and you can still run it off a stand, you need even less power. With a 5 hp motor, even with the air stealing a little power he is good to go

ratled
ratled I agree with the subbie comment BUT ragnor wasn't talking about using a subbie (I did ) ragnor said he was using a 2.5 mini surface dredge and wanting to know about how deep he could go with it. That's where my comment was headed.

 

[njcommercialdiver]

wish i could find a subbie on the east coast, every one ive seen is in california and i would have to morgage the house to ship it here.

mike,
i started there back in 2007, my first year i had a couple pans and a a51 sluice, the next year i came back with a 3" keene dredge and then spiralled downward from there.

as of today, i have a couple sluices, 2 highbankers, a 3" keene, a 3" homebuilt backpack "sneak" dredge, a 4" and a 5", this year im building a 6" with twin proline 400 pumps and honda 200s. just think the bigger the nozzle, the fewer rocks you have to move LOL

 

[russau]

You wont have to pay shipping all the way from California if you would buy it from a local dealer closer to you! Then you only pay shipping from this local dealer to you OR go to him and pick it up!

 

[brianc053]

All these posts prove that a gold pan is a gateway drug to a 6" dredge

I'm up to a 2.5" and will never need anything bigger, well, maybe a 3" will be better

Last year I bought a 3", and after a half dozen uses I'm already wishing I'd gone with a 4"....

I'm afraid I'm hooked.

- Brian

 

[njcommercialdiver]

russau, the closest dealer is still 600 miles away, us northeast guys are like the baztard stepkids (wont let me post it right way), even the gpaa doesnt have many claims east of the mississippi

 

[Mining engineer]

Russau has the right idea. Been through this thought process before. Came up with a design, but never had the chance to build it.

Do you have a plain, old sluice laying around somewhere? If so, you can convert that into an underwater sluice so that your system doesn't have to pump way up high. The only problem then will be the tailings piling up. ...And that's assuming your hole is ONLY 30' deep! It may be much deeper below lots of rocks and debris.

Too bad there wasn't some way to divert the waterway so you could pump out the hole and work it without diving. Oh, heaven forbid! You might damage the Earth!

You could divert the water if you apply for a 301 permit. Takes about 3-6 months approval. Just had to be put back how it was when you finish.

 

[russau]

not really russau. If running a true subbie you don't have the lift requirements and the pump will work. The biggest power killer is is the breaking of the water surface and the lift above. if you run like this off a stand you probably are good to go. If you take fully underwater, and you can still run it off a stand, you need even less power. With a 5 hp motor, even with the air stealing a little power he is good to go

ratled

View attachment 1333976

ratled , I know this is a old post BUT here goes. I've never seen a undewrater subie that is used as you pictured ir on the surface . Winners used his with small floatation like I would expect it to be used. It would float when not pumping water through it and surface (or close to it when not pumping water through it ) As you probly know , the lower you have to raise the water to the device the less pump / engine you'll need , as Winners quoted. Years back while I was building my own 6 inch subbie I was going to use my 4 inch pump / engine setup with my Brown air compressor . and plan for it to do as Winners operated his. BUT as old age set in ,I had to stop dredging / prospecting and sold it all to a guy from around Chicago Il. for my loss ! ;( and at 78 ,I sure miss it a lot !!!