newbie in gold dredging

[Finn]

Hi Fellows

I have plenty of experience on dredging from commercial diving work but i have never done any gold dredging.

I do highbanking on my claim by the clear water river which is about 200' wide.

The bedrock is so that i think that dredging might be a good idea.

I am planning to build a 8" dredge powered by two Keene 350S/22hp Honda V-twins. Would this be a practical combination, what do you say?

I have used only that type of nozzle where pressure water lines are connected directly to the nozzle which i am holding. Like holding the jet log and dredging

directly with that.

Now a 8" nozzle with two 3" high pressure hoses connected would be awkward wouldn't it.

I have seen plans where this "log jet" is somewhere close to the surface and a suction hose with the nozzle at the end is connected to it. How long can that

impotent hose could be without losing to much power? Would 20' be too much?

In our commercial diving operations it was never necessary to lift the material above the water line. Do you think that this kind of combination is power full

enough to lift the material something like 20"?

Have you ever seen or even heard about dredge constructed on a boat? Like 30' open, self bailing glass fiber boat as a platform?

I would appreciate all comments, thanks.

Salud

Finn

 

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[russau]

It depends on what state /river you plan on using this dredge! I don't think anyone builds a venture nozzle that big... Im assuming you are going to make one yourself. 20 foot of hose shouldn't be any problem. Id like to hear about how you plan on the material in the sluice (mats/riffles/etc) . pictures go a long way!

 

[Hoser John]

EZ to do as long as you have plenty of $$$$$$$$$$$$$$. Who, what and where is the predicating factor. Boat ez, 8" powerjet nothing to it as Dahlke,Keene,Proline all make them in numerous designs. 20' depth no big deal either BUT past that and dive tables kick in so you say x pro so that is no big deal either. Plenty of engine for sure BUT jet is most important piece to the lift puzzle,flare mandatory. More info needed as ran 6"-8-10"- for years. John

 

[Reed Lukens]

Finn;4768587
I am planning to build a 8" dredge powered by two Keene 350S/22hp Honda V-twins. Would this be a practical combination, what do you say? -

Yes, it will work great.


Now a 8" nozzle with two 3" high pressure hoses connected would be awkward wouldn't it. Very awkward

How long can that impotent hose could be without losing to much power? Would 20' be too much?

Actually 20 feet wouldn't be enough hose. Go for 30 to 35 feet of hose. With an 8" its easier to bend it in a circle sometimes to make it easy to move left and right on the bottom depending on the depth. Either way, a 20 foot hose will be too short for comfort. Just use a standard powerjet at the box for your waterpump infeed.



Here's a pic of the powerjet and the other shows the hose being operated with one hand by using T103 inner-tubes to add buoyancy to the nozzle and hose.

Also I do have an 8" box, Jet Flare with a header box also and nozzle for sale in California if you would like to talk about it.

 

[russau]

Reed what a RUSH that would be to run that dredge and see the cleanup!!!! Heres hopeing that 2016 will bring some GOOD NEWS for dredgers!

 

[littlenugget1]

just the only problem that is is what you have to go through here in idaho if that is the clearwater river that you are talking about. with that said idaho has a 5 inch nozzle size. but if that river your talking about is not in idaho then forget my post.
hope this helps.

 

[winners58]

so your in Ecuador, I'm wondering how fine the gold is, you don't want to pull a Todd Hoffman.
Dredges I've seen pump the sand slurry up 4 or 5 feet then have like an over sized beach box 4 or 5 feet wide.
the gold could be good and chunky on the west coast I don't know but the type of gold will determine your build.
I would suggest talking to Alan Trees at http://golddredgebuilders.com/ he would be able to give you some pointers.
his 8" builds use an underflow sump to catch the fines and send them to a separate sluice.

 

[Finn]

Thanks for everybody, good comments all.

Yes, 8" is the limit down here. I am working on a quite big river, so i was thinking to go for 8" right away. The gold seems to be coming from low sulfide mixed type VMS deposit from up in the mountains. The lode is inside the national park limits. The gold from VMS deposits is typically very fine but this one has some coarser stuff too. Or maybe there is an other unknown lode some where nearby..

Catching the fine gold with a dredge is not an easy task, i know. I have an old, open type 30' glass fiber fishing boat hull which i am planning to convert to dredge platform. It's a self bailing so i may cut off the whole transom down to deck level. At the left side i have 4' wide outwards opening door which will be good for access to the water. I will have 6' by 20' feet even space available for the sluice alone easily, if needed. The flare will come in thru the hole which i will cut to the bow section of the hull.

I will go for traditional one inch angle iron riffles, heavy expanded metal crate, miners moss, slick plates, alaskan curtain and a diffusor. I have so much length and wideness to spent that i strongly believe that i will be able to manage the slurry velocity and stuff along the box. I am very familiar with Randy Clarkson's and Hamilton's studies, i made my highbankers according to those principals and i am catching 300# stuff.

I am going to manufacture everything down here locally. I'd love to buy a flare and a nozzle and a jet log and stuff factory made but import duties and custom formalities and freight costs and insurances would add to price so that they would cost more than a double compared to factory price in U.S. Those Keene pumps i will have to import off course.

So this jet log is always connected directly to the flare so that there is no pipe or hose in between? I was just thinking that if there would be like a suction hose, jet log then 10' rigid plastic pipe and then the flare coming in. Wouldn't it give stronger suction when the impotent suction hose is kept as short as possible? Or is like "**** the aerodynamics, it's the horsepowers that counts." kind of thing? This is obviously a newbie question but i have to ask anyway.

Yes, Todd in South America. No, i've been here for 12 years and work my own concessions that i have found and prospected myself and i have all water and environment and mining licenses. Mining is a very risky business and this will be a big investment for me in money and time vise so i try to be careful in every detail.

I've been working with dredges quite a lot in commercial diving but i've never seen that kind of buoyancy idea in practice. Looks excellent, thanks for sharing Reed. I've seen your videos naturally. Max. three inch monitor for hydraulicing is allowed to use here too in certain places, by the way. I just remembered your clips about that theme.

Salud

Finn

 

[Reed Lukens]

QUOTE=Finn;
I will go for traditional one inch angle iron riffles, heavy expanded metal crate, miners moss, slick plates, alaskan curtain and a diffusor. I have so much length and wideness to spent that i strongly believe that i will be able to manage the slurry velocity and stuff along the box. I am very familiar with Randy Clarkson's and Hamilton's studies, i made my highbankers according to those principals and i am catching 300# stuff.

Forget the Clarkston Crapola, that's not on an 8" dredge. You want to be able to run it maxed out for the best through put so you really need to rethink this project and read these links at least 3 times over a few days to let it sink in.
promackdredge.jpg Photo by Coochee | Photobucket

» Double-screen Classification System in Dredging

So this jet log is always connected directly to the flare so that there is no pipe or hose in between?
No... Look at the pic, there's 6 feet of pipe hooked to the flare before the jets at the bottom.

Yes, Todd in South America. No, i've been here for 12 years and work my own concessions that i have found and prospected myself and i have all water and environment and mining licenses. Mining is a very risky business and this will be a big investment for me in money and time vise so i try to be careful in every detail.

If you can get 30 or 50 gallon drums to make floats out of, you will be a lot better off because you don't want the dredge to be able to rock side to side.

 

[russau]

Dave Franks (Vortexrx) also sells his plans for his venture for your jet! Ill look for his link on ebay

 

[Hoser John]

Jet logs are pretty cheap and cast very heavy to match your dual induction system for your dredge. Over/under classification will separate the fines and increase your take considerably. For fines the HUGE flair prior to introduction into the recovery system is MOST important to deairate, spread out the flow, slow it down a bit and let them fines drop IMMEDIATELY as once moving fast in the box they just run out the end. Keep your discharge end OUT of the water to increase flow down under for better fines retention as back pressure forces the fines to stay on top level and adios. Lotsa luck-John

 

[Finn]

I am reading and thinking so that the smoke is rising from my head.. I'll back back when it has cooled down a little.

Salud

Finn

 

[russau]

Listen to Hoser!! hes been there , done that!

 

[Hoser John]

Thank you very much for the compliment Russ, tons a au 2 u 2-John

 

[bill-costa rica]

Finn , I hope the smoke is not because you are pissed. the guys that are trying to help you have many , many years building and working dredges. I heard that dredging was illegal but not enforced in Ecuador ? is that right ?

bill

 

[Hoser John]

Great question Bill as Mad Dog is about ready to go back. He ran 2- 12" with a half dozen locals but VERY wild wild west then in the 90s. Getting the gold was tough...getting it/cash out very much harder then..now?. Finn also go to proline/keene/dahlke websites as pics of triples and many designs there also. You can also modify a triple sluice to catch the microfines very well also. Isn't it almost summer down in SA?John

 

[Finn]

Hi Guys

I really appreciate your help folks, i am sorry if gave an impression that i am some way pissed off. I am just re-considering my plans because of what you have advised this far.

Reed wrote about the stability of the platform. The hull that i have is low deadrise hull, 8" wide. Such hull is more stable than a catamaran hull of same the width on waters where are no wind waves or swell, as usually is the case on rivers. I like to dive from platform rather than from the shore so this will provide enough space on board.

Dredging is allowed down here, there is a LOT of bureaucracy, but it's possible. One must have a "free miners license" before one can register a claim. For to get that one must register in local IRS as a miner, then one must get a certificate from local "Mineral Resources Institute" that one has taken a 5 days course about mining in Ecuador. Get a document from public notary that one is planning for legal operation. With those papers one has to go to ministry of mining and get registered there. Then to the sub-secretary of mining in a province where the operation is, get a legal address there and then one may stake a claim. Then mining plan has to be approved, local communities approval, ministry of environment approval and water office approval, agree with land owners about roads, trees and compensation, every thing depending from each other. When all the paper work is ok, then the mining inspector comes to check the site and gives his approval for to start work. That was a short explanation, i takes at least a year in a real life.

They are very keen to hunt illegal operations down now. One military person was shot dead and three were insured when they attacked an illegal dredge operation last year. Both miners we shot to dead and one indian who was nearby died also in a raid. They are using military explosives to to destroy illegal back hoes and other equipment.

So if some one is interested to come down here, it's better to take local laws seriously or there will be a repetition of "Todd in Peru", or worse.

There is only a handfull of legal placer mining operations in a whole country now, so if some on tells you that he has a claim and all paperwork done, you better check and then double check before introducing the money. There are also limitations of having non-ecuadorians as a legal partner in certain kind of operations.

The Central Bank buys the gold from small operations thru their certified agents. Selling it some where else is illegal. Prices are normal, 70 - 85% usually.

But back to the dredge, i will study more about dredge sluices as Hoser John and Reed recommended, thanks once again guys.

Summer is a very confusing term here because there are only two seasons, rainy and dry, when it's raining on mountains it dry here on the coast and opposite. They call those seasons summer and winter depending at which part of the country one is and i don't understand their logic. Any way the warm and rainy season is about the begin here on the coast. El Nino is prognosted to be very strong this year and it may bring heavy, non stop rains until next april to this part of the country. My operation should not be affected because it's on the eastern side of Andes.

Salud

Finn

 

[Hoser John]

Big move Finn, very convoluted walk down the legal path. Investing that much money is indeed a tough decision. BAD price paid for gold(70%+, as price at $1060+ is in the toilet(down over 40%+) so a very chancey investment. A doctor friend told me yesterday to stay away for mining, he has a home there for many years, but Quito is nice to live and cheap. Know many stories that are good-visitors/retirees but mining and gold resale not so. When your government nationalized the banks-took the dollars- it ruined a few friends for life. Wish you all the luck in the world-John