Deal or no Deal? Anyone familiar with this dredge? (Merced craigslist)

[spaghettigold]

CUSTOM 8" GOLD DREDGE

There were no photos in the listing, I haven't tried to contact the owner, probably won't. Going by the description this sounds like some kind of professional setup. On- board jig? Sump off the end of the sluice that feeds the jig maybe?

New hose alone for this dredge would probably cost what I paid for my entire 4" dredge. If it's all in good condition it sounds like a deal. Dono about the engine/pump and jet log though, having to repair/replace those might be difficult $$.

its not this one but this may show what a beast it might be. This is a 6 inch,with vibrating deck screen with minus 2mm material fed to a centrifuge built by a dredger in nz.If portability is no issue and the deposit ,(much black sands,type of gold )needs such a recovery system and its a paying deposit too it might be worth the effort,otherwise just a expensive pita . Pfinegoldthread1.jpg Photo by Coochee | Photobucket
Pfinegoldthread2.jpg Photo by Coochee | Photobucket

cheers-emilio

 

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[specksandflecks]

Not a 8"-forget boat motor as your own powerjet works much better and no extra weight. Way overpriced not $6k at the absolute most. Side boxes too small. Take a gander at this setup as much better-John

How much above water lift were you guys achieving with those triples? I'm guessing 12-16", without a flare to conserve energy?

 

[specksandflecks]

its not this one but this may show what a beast it might be. This is a 6 inch,with vibrating deck screen with minus 2mm material fed to a centrifuge built by a dredger in nz.If portability is no issue and the deposit ,(much black sands,type of gold )needs such a recovery system and its a paying deposit too it might be worth the effort,otherwise just a expensive pita . Pfinegoldthread1.jpg Photo by Coochee | Photobucket
Pfinegoldthread2.jpg Photo by Coochee | Photobucket

cheers-emilio

That is something you probably don't see everyday. Love seeing the more 'unconventional' stuff like this.I know the difference between centrifuges and jigs but have never operated so unsure which would be more effective in this kind of application?

 

[spaghettigold]

Yes quite interesting piece of equipment,one can see the work and determination in this built.
I have no experience with both jig and centrifuges.From what i,ve read the the jigs are prefered in placer ops,the centrifuge seems to like material screened to 1/25 inch,may some old fox here enlight us..
-emilio

 

[specksandflecks]

[FONT=Jura, sans-serif][FONT=Jura, sans-serif]"The CVD Knelson Concentrators are suited to applications where the target mineral exceeds 0.5% of the total feed solids.[/FONT][/FONT]"$$ ?? :/ Doubt I'll be pulling 1/2 lb au for every 100 lbs of 20 mesh though.

 

[Hoser John]

That 6" was the first semi-flare header keene made,my old PESCO design, coupled with a 18 hp IC specificially matched to a special high dome to go with the higher hp. 35' depth easily with rpms to spare. Decompression was a drag but poundage wasn't .

 

[spaghettigold]

John,i try to take notes ,if you ever write a book ,i buy it.
emilio

 

[spaghettigold]

[FONT=Jura, sans-serif][FONT=Jura, sans-serif]"The CVD Knelson Concentrators are suited to applications where the target mineral exceeds 0.5% of the total feed solids.[/FONT][/FONT]"$$ ?? :/ Doubt I'll be pulling 1/2 lb au for every 100 lbs of 20 mesh though.

Don,t know if this applies for all the centrifuges,if its like that , then you would use the centrifuge only for clean-up of rich concentrates.Like others said :the deposit predicates the equipment.
For good fine gold recovery under heavy blacksands conditions with my 8 inch ,my current method is to have a milder waterflow.less watercolumn over a longer classified fines section,giving the fine and flat peaces more time to settle thru the classifier, but that involves a sluice tender pushing out bigger or flat rocks that might stop in the sluice.Also a wire mesh classifier section
instead of only punch plate for more open area /effective classification. Also a bit bigger openings in classifier (1/3 inch) then most use .This is what use to get the fine floatgold out of suspension,under the classifier.
Under the classifier; Under classifiers(especially in the beginning of classified section and especially under punch plate) it seems the waterspeed is greatly reduced,so i don,t use miners moss there.Miners moss under expanded is great and scientifically prooven method(clarkson) -for operations where the material is preclassified before running thru the sluice.The material then can run in a low watercolumn with proper speed over the expanded/moss.
In my short dredge ,in the short fines section with low waterspeed(because of the friction from classifier) the moss tends to clogg up ,especially when much heavy sands are present . Thats why i use expanded over ribbed mat there.
I use the moss further down the sluice under the open area riffles,where waterspeed is increased and the riffles get the whole watervolume to work with.
For rivers with much heavy sands i clean up more often.
Hydraulic riffles (fluid bed)would be interesting in the future maybe.-emilio

 

[specksandflecks]

Yeah I think you're right Emilio. I was just trying to find some basic info on how they worked, capacities/TPH, basic differences kind of stuff.

I just thought that one was interesting since apparently its some kind of continuous discharge. I don't know why it's so high with that one, I'm sure its highly capable equipment with a price to match though.

Any pic's of your dredge would be great, less is more, simple is more better if it gets the job done. The least expensive, least complicated way to pull 90+% of gold 80 mesh out of that 8" dredge water column would be a nice thing to know. Probably not the cheapest question to answer though??

 

[spaghettigold]

sorry,my fault,i thought you know already,i,m running a gravity dredge,thats all i,m allowed to do where i go . I have a video on youtube ,from last years trip, in italy,dredging up what the romans left for us . Or the whole thread here on t.net http://www.treasurenet.com/forums/gold-prospecting/433395-8-inch-gravity-sluicing.html I still not tested my 8 inch for losses in a flower gold creek i know ,have to wait for spring to come.-emilio

 

[specksandflecks]

Thanks for that what a great thread.

 

[spaghettigold]

thanks specks,still much to do there.Will post again when something new is accomplished.

emilio

 

[Hoser John]

Each and every riffle ever made is a hydraulic riffle -John

 

[spaghettigold]

 

[spaghettigold]

this ones Patent US4863588 - Riffle bars - Google Patents

emilio

 

[spaghettigold]

When i first learned about them in the other forum where i,m also member ,, they where called hydraulic riffles,used largely in the landbased ops in nz,it took me quite a while to understand that it was the same principle that was called fluid bed in the sluices here.How effective are they for fine flower gold recovery in a dredge?

emilio

 

[specksandflecks]

Garnets and that shale type of bedrock that holds the gold so well but comes apart in tiny flakes that tend to outstay their welcome IMLE. Maybe also if you are running material with a high sediment load?

Really I'm guessing the biggest issue with fines recovery on an 8" and lesser extent on a 6" is the sheer volume of water to material. BUT that is how dredges work so I guess we have to deal with it!

I'm sure HJ gets good fines recovery, but I doubt that's his focus. He basically lives in the Motherload, so bigger fish to fry no time for the fly. BCR on the other hand could be primarily fines.

 

[Hoser John]

?? Haven't lived in the Motherlode in 25+ years. Fines under 50 mesh paid for my sons college education,trips to Costa Rica and Hawaii a dozen times. NEVER turn your back on fines as a simple over/under unfettered is and always will be king in my world-John-John

 

[russau]

When i first learned about them in the other forum where i,m also member ,, they where called hydraulic riffles,used largely in the landbased ops in nz,it took me quite a while to understand that it was the same principle that was called fluid bed in the sluices here.How effective are they for fine flower gold recovery in a dredge?

emilio

captureing fine gold is Part the equipment but mostly the ability of the operator to set up and run his equipment effectively! nobody runs or sets up their equipment the same 100%

 

[spaghettigold]

Thanks for all the answers to all,please be patient with me ,i hope i dit not create the impression to be disrespectful,thats the last thing i want,i hope my english or my type of humor does not lead to missunderstanding. I,m still learning,both english and dredging.
John: if i have lived near you and dredging was,nt banned i california i shure would have tryed to apply for beeing your dredging slave /aprehentice.
Specks: Yes, in nz they use the hydraulic riffles because they have many rivers with fine gold that is trapped in INSANE amounts of blacksands,so that conventional riffles get clogged in minutes.So even when you have a set up that catches the fines,it looses effectivity because of packing.They seem to have so much heavys ,they run viable mining of blacksand.
Russau:my fault,i did not point out that the river where i where in my video holds alot heavies too. 2 cleanups per day required.Then i have another river that is worst,comparable to nz conditions.As i mentioned i cleanout more often,but that is time/energie consuming,especially because for cleanout i have to detache the 8 inch hose to stop the waterflow.
Thats why i,m interessed in the hydraulic riffles ,they would allow me to run longer with no cleanout and are a riffletype that could be possible to run by gravity,but at the same time i ask myself if they are good to catch the fineflower gold since the hydraulic riffles are installed with the bigger riffletypes,not within the expanded metal.

emilio