UNDERWATER gold dredge ***HOW CAN I BUILD ONE***ideas?

[keepmehumblelord]

hey everyone, so im sure you have seen Glen Lebaron on bearing sea gold. His dredge is a genious idea and its mainly for slower moving water but i know the pools of slow moving water are drop off points as far as gold goes. I would like to build one this summer if possible and does anyone have any idea how to build one. I dont understand the dragon on the gold show where do the big rocks go because its a enclose sluice box. I really want to understand how to build one. ANY SUGGESTIONS. its not rocket science but it will take much in depth precision to make everything work.

 

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[kazcoro]

Just a guess on my part, but it seems to be part fluid bed, part dredge. The rocks get kicked out same as any other sluicing operation.

 

[fowledup]

Gould Engineerings' Bazooka is another example.

 

[AzViper]

What happen to your adventures of mining in Arizona with the claims you bought? For a few weeks all we read about was, claims, trucking water, backhoes, etc.

 

[kazcoro]

He's got the fever....bad. At least he is listening to reason. And looking to you guys for advice. But, yeah, that was what I was thinking.

 

[Hoser John]

Oldest and cheapest form of dredging is underwater dredges. Keene still sells them also. Go for the units with a suction nozzle as miniscule recovery boxes require hose classification prior to being sucked into the box. If you use a powerjet you get a mixed up mess immediately prior to recovery and much less recovery. That unit is NOT new as Trev Alty from the NZ has built them for many MANY years. Go to the "OLD" GoldDredger.com forum for complete info,may also find in new forum under search. Must run with floats just like a regular dredge,keep absolutely rigid to prevent ALL side to side roll as instantly dumps out the recovery system. Instant backfill if on the bottom. Anyhow Trev from NZ also posted on old Prospectors Casche also. I MUCH prefer surface floated as MUCH more classification,better fines recovery and the ability to keep a eye on the box(none on underwater units) is paramount for righteous operation---John

 

[keepmehumblelord]

You guys crack me up lol. The arizona thing is still in play. Just thinking ahead for the blazing hot summer in az. Why not go where the temp is not as bad AK anyone?

What happen to your adventures of mining in Arizona with the claims you bought? For a few weeks all we read about was, claims, trucking water, backhoes, etc.

 

[AzViper]

You guys crack me up lol. The arizona thing is still in play. Just thinking ahead for the blazing hot summer in az. Why not go where the temp is not as bad AK anyone?

Well I had to ask. Your like a kid in a candy store bouncing off the walls, everyday it was something new. I look forward to the summers. If you been here as long as I have been you appreciate the heat and learn to handle the heat. I was prospecting and mining in the heat this summer. You learn to pace yourself and drink lots of fluids, but I look forward to reading your next adventure... Good Luck...

 

[kazcoro]

Just thinking ahead for the blazing hot summer in az.

And,. that is why we drywash. You can get at least two months of the dryer than a popcorn fart weather no matter where you are north of Tucson.

 

[Timberdoodle]

It was hard to see much of the "Dragon" on the show to give a good description, but from what I saw I think he is running a 2 stage system. I believe material is brought to a screen separator which allows the larger material to be discarded and the smaller material is caught below the screen in a sump. The sump is then run as a separate system with it's own suction jet drawing from the sump and feeding the sluicebox. This type of system will achieve much better recovery than a standard submersible because the flow rate to move the smaller material is much less than the requires flow to move the large rocks. This type of system has been deployed on surface designs also but does require considerably more design than a standard subsurface dredge. Building a subsurface that will capture fine gold is a tough job and requires the understanding that pressure drives the flow of water/material unlike a surface unit which benefits from gravity flow and angle to help move material over the sluice. It is not that hard to get fine gold in a subsurface unit, but it is very hard to get it while trying to move the unwanted large material through. If getting gold on your claims is your goal and not the challenge of building and testing equipment for several months then I recommend buying a surface dredge.

 

[Vagadero]

I don't know the dragon dredge but here is something similar:
"Six Inch High Performance Sub Surface Classified to 12mm - Gold Dredge.

This is a very powerful production unit designed to move large quantities of material through the sub surface classifier which is equipped with tapered grizzly bars to ensure no blockage takes place. Gravel is reduced down to 12 mm which means only the productive pay dirt is processed.

From the subsurface classifier the 12mm undersize material is fed via a venturi jet to a small 250 mm wide sluice equipped with hydraulic riffles complete with pressure gauge so the optimum pressure is always maintained through the hydraulic riffles. This ensures the black sand and tin concentrates never compact thereby markedly increasing the fine gold retention under the black sands.

The six inch venturi power jet is fed by three 1” hi pressure nozzles set at 11 degrees and is tapered so the six inch suction hose fits inside the wider end and delivery from the power jet fits inside the flexible hose fitted to the sub surface classifier. It’s a completely block free system which ensures maximum through put of gravel. No blockages equals much higher performance and more fine gold being caught.

The unit is powered by twin 6.5 HP motors equipped with pumps capable of 60,000 litres per hour each. Two by three inch suctions complete with strainers ensure maximum flow is delivered to the venturis on the suction 6”suction nozzle as well as the venturi which sends the undersized material to the hydraulic riffles in the sluice box.

Exhausts are water cooled on the motors and exit into the water at the rear of the dredge making this a very quiet machine heard no more than 100 metres away from where the unit is operating. Air is supplied to the divers via a hi performance oil less compressor equipped with a Teflon cup which delivers over 150 litres of air per minute. One of the PVC floats is a reservoir for the air which ensures up to three divers never run out of air at any time even when working hard.

It has been designed and built by an experienced professional gold dredger with over ten years of full time professional dredging experience behind him, but has only been run for a short period to ensure the unit works the way it should... so it is essentially brand new. It is designed for ease of assembly and disassembly with quick release camlock fittings used on all pipes and hoses. Stainless bolts and Nylock nuts ensure the unit is easily pulled apart and moved or transported by one person when required. Assembly or disassembly takes about half an hour.

The floats are made from heavy duty PVC pipe and are adjustable forward or backward to achieve the right balance and angle on the classifier and sluice box. In addition the 250 mm sluice is able to be adjusted for angle independently of the main unit. The floats are also able to be extended in width to ensure stability in swift water if required.

The suction head at the working end of the main suction hose is designed for ease of use with the exact angle for the handle to reduce operator fatigue when using the suction nozzle for long periods. The nozzle is necked down by a steel ring which doesn’t restrict the flow of water but prevents any rock over 5.5” from entering the suction tube thereby completely eliminating blockages anywhere within the unit.

This machine has been constructed to cope with large quantities of material yet is able to save 100% of the fine gold that virtually all other dredges lose due to the processing of large stones and rocks over the sluice where the gold is caught. Because all material is classified to 12 mm the flow rate over the hydraulic riffles can be infinitely adjusted to suit all working conditions.

A professional high performance dredge for anyone wanting the best through put of material with the maximum retention of fine gold.

Photos be on here soon... Inspection is welcome"
Source:
Six Inch High Performance Sub Surface Classified Gold Dredge | Miscellaneous Goods | Gumtree Australia Tablelands - Topaz | 1069632670

 

[Timberdoodle]

Sounds like an interesting design. Probably needs plenty of river depth to classify subsurface, but gets the benefit of great suction strength. Nice find, wish they loaded pic's.

 

[ratled]

There is plenty out there if you search the title "of submersible dredge" or subbies. True subbies are underwater either on a stand on the bottom or hang from a chain completely under water. The beauty of these they need way less HP as you aren't needing to lift the material out of the water. Keeping them level, especially in faster water, becomes and issue.

A lot of folks, including me, run them a semi subbies where they are right at the surface but the material never breaks the plain of the water line. Here is our 8"
These are a lot more forgiving

 

[meMiner]

The nice thing about an underwater dredge like the Bazooka is they are very portable and do not need a large pump. You can have a 5/6 inch dredge that is easier to move around than a 2 inch surface. I have one of the original 4/5 inch. The downside is it needs to be completely underwater, so not good for really shallow areas. Also, unless you put a suction hose on it, then you are blowing out your tailings just behind where you are working. On the other hand, bringing along suction hose makes it significantly less portable. Also, I am not sure how much gold it keeps vs a well set up surface dredge, but boy it moves a greater amount of dirt than a small dredge. As such, one option is to make the hole and clean out the overburden with the subsurface dredge and then clean up the exposed bedrock with a surface dredge. Last thought - there used to be somebody from New Zealand who made electric subsurface dredges that had an internal underwater sluice. His videos showed they worked. It was an interesting idea, but I never saw one in operation.

 

[specksandflecks]

hey everyone, so im sure you have seen Glen Lebaron on bearing sea gold. His dredge is a genious idea and its mainly for slower moving water but i know the pools of slow moving water are drop off points as far as gold goes. I would like to build one this summer if possible and does anyone have any idea how to build one. I dont understand the dragon on the gold show where do the big rocks go because its a enclose sluice box. I really want to understand how to build one. ANY SUGGESTIONS. its not rocket science but it will take much in depth precision to make everything work.

On the subject of slow moving water being a drop out point.. I found such a place where I suspected this was happening. Turns out I was much more right than I ever wanted to be as everything dropped out there. Boulders, sand and everything between. So there I was 30+ feet down with my '~4" ' nozzle and mountains of material at my feet. UM OK now what ? Sample sample sample... Did that and found a few flakes, nothing of note really.

Feeling pressed for time and overwhelmed by the sheer volume of material, I dropped back downstream ~200' where the water and bedrock were much more shallow and started finding nice pickers sitting on top of my 1/8" hand classifier screen. If those little nuggets made their way up outa that abyss, what treasure could still be lurking down there? Only the shadow knows. Maybe someday I'll return with a more methodical approach.

 

[Sluicedog]

You can watch the dragon in action on this short clip: The Dragon: Underwater Dredge | Bering Sea Gold | Discovery

You might also try to build a Gould Bazooka underwater dredge, It use centrifugal force through a tube with slits inside. You can read about the tech on the Gould web site.

I like the submersibles because there is no air/water interface to capture and steal the super fine gold I sluice for on the NH rivers.

 

[Reed Lukens]

Years ago I'm sure many of you remember there was a guy who ran a grizzly on his 10" subbie and ran the fines to a 4" dredge on the surface. It may have been Glen Oates but I made an 8" Keene subbie into a grizzly machine also. I think Lebarrons ideas all came this topic that we did years ago.
Here's a link to Trev's suitcase dredge plans
Prospectors Cache Forum - Viewing topic #13 - SUBSURFACE DREDGE TECH

 

[Reed Lukens]

Then here is a great quote from the subsurface dredge tech link on the page above. -
kaveman
Date Sat Nov-05-05 10:58 AM
Message



In response to Reply # 19

Hi guys, sorry for not being more active. Honestly there hasn't been much to report since 2003. The distance between the home workshop and the dredge grounds(about 2300 miles)has just about stopped any progress. The 'big' dredge didn't even make the trip this year since it's still only half complete. We did run it some last summer and the one modification that did work as planned was the nugget trap. The nugget trap is now on the suction side of the jets and consists of about a dozen angle iron riffles based on the Klondike study. All lead, iron, and gold larger than small flakes held up in the underwater riffles of the trap very nicely. Only the fines continued past the jets, over the grizzly and into the sump to be lifted to the surface sluice. I'm not really sure any of our experiences really relate to what's being talked about here since the fines are still being subjected to the mixing zone of the jets before we attempt to recover them. I've had my swing at sumping prior to the jets and I'm done messing with that idea. Don't mean to discourage anyone because I'm sure someone will eventually figure it out, but we just haven't got the time or opportunity to continue with it. I've 'wasted' the last ten dredge seasons worrying about a percentage of the fines. Fiddling with that has kept us out of the water, or sometimes in the water struggling with equipment and modifications that didn't work.

The last full season working with an inefficient subsurface dredge that dumps half the gold back into the river netted us 26oz of really nice gold. We have yet to see a two oz season now that we're working on an efficient dredge that saves ALL the gold. Time in the water gets gold. Dreaming about the 'perfect' dredge just gets you through the winter. We made the mistake of letting those dreams carry on into the dredge season and I will forever regret the lost days and aggravation. I wish I had the dredge we worked ten years ago and had never thought of a 'better' mousetrap. It WILL work, but in our case we just aren't set up to experiment with it. Too far from home and too few days available for testing.

 

[russau]

Thanks Reed for the trip down memory lane! it must be just past "Hollywood Blvd"!

 

[ratled]

Thanks Reed for the trip down memory lane! it must be just past "Hollywood Blvd"!

YES! Thanks Reed. Kaveman (and Steve Herschbach) where instrumental sharing their information when we made ours. I forgot about those guys over there back then

ratled