? what size box for an 8" dredge ?

[dredgernz]

I am building an 8" dredge with 2 x 3" powerjet - 2" at the log
it goes into a flare - 8" to 16" 90cm long
box could be a - flare type - 60cm opening out to 120cm over 2meters long
to slow down the flow - very fine gold present in black sands
or 3 boxs at 80cm the first 60cm then 90cm then 120cm

any idea's ?

cheers
Mike

[Hoser John]

A flarejet with over/under clasification is a must for fines retention. A suction nozzle will not remix the fines and ruin the classification the hose provides. I know the powerjet sucks better but you stated fine gold and they are not the best for that. GOOGLE keene and see the huge amount of size differences in differing dredges, even the same size. All dimensions are different for a dredge when it is a straight ol'style box vs o/u-go from there, and recheck log size as what you describe(I'm great at" but lousy at cm/mm as Ize an american) seems a bit small for a on top of the water box. Trev in NZ has a pretty good underwater box unit he uses in NZ. tons a au 2 u 2 -John

[dredgernz]

A flarejet with over/under clasification is a must for fines retention. A suction nozzle will not remix the fines and ruin the classification the hose provides. I know the powerjet sucks better but you stated fine gold and they are not the best for that. GOOGLE keene and see the huge amount of size differences in differing dredges, even the same size. All dimensions are different for a dredge when it is a straight ol'style box vs o/u-go from there, and recheck log size as what you describe(I'm great at" but lousy at cm/mm as Ize an american) seems a bit small for a on top of the water box. Trev in NZ has a pretty good underwater box unit he uses in NZ. tons a au 2 u 2 -John

Thanks John
yes, its a volume pump of 2 x 3", so don't want to restrict the pump to much, but have ample power
so the trick is, not to - Overwater the table, I rekon.....hense my plan for a "flare box" that opens from 60 or 80cm to 12-150cm - over 2 metres +.
I had a 4", that worked great, - 40 to 80cm/150cm - but there was no black sand on that river.

Cheers Mate

[mrs.oroblanco]

WOW!!!! An 8" - whew, I can barely handle a 4". Hope it works well for you.

I, personally, have re-vamped our box, by necking it down (the part that it came with), and extending it. We kept finding gold at the very edge of the box, so I know we were losing some. We built two 3' sections that would bolt on to the end, so we had an extra 6' of length, and we could take it apart and fit it together when we were moving it. There was still gold in the lower part of the first extra 3' and none at the middle of the 2nd 3' section.

I think part of it will be decided by how much water pressure is going over it.

B


PS - Don't know where you are dredging, but I'm sure you already know that 8" are illegal to use in many areas - some have 6" limits. (some have even smaller limits).

Good Luck and Happy Dredging !!!!!!!!!!!

[dredgernz]

Hi Mr-s B
Thanks for the reply, great to hear other dredger's experiences.
In new Zealand, you can get a 200mm/8" nozzle permit...and we don't have Arnold Bilderberger-" Don't come back..."....running things... trying to save 2 indian's & 3 salmon.
Gold mining built Nz & California, & yes...an 8"...sure do'es move some rocks...nozzle is 7" to prevent jams.
Merry Xmas
Dredgernz

WOW!!!! An 8" - whew, I can barely handle a 4". Hope it works well for you.

I, personally, have re-vamped our box, by necking it down (the part that it came with), and extending it. We kept finding gold at the very edge of the box, so I know we were losing some. We built two 3' sections that would bolt on to the end, so we had an extra 6' of length, and we could take it apart and fit it together when we were moving it. There was still gold in the lower part of the first extra 3' and none at the middle of the 2nd 3' section.

I think part of it will be decided by how much water pressure is going over it.

B


PS - Don't know where you are dredging, but I'm sure you already know that 8" are illegal to use in many areas - some have 6" limits. (some have even smaller limits).

Good Luck and Happy Dredging !!!!!!!!!!!

[mrs.oroblanco]

Don't tell anyone, but I almost got my arm broken with a 6" dredge................man that hurt. And the hose was so stiff, I couldn't get it around to cut the engine. (luckily, there was someone else there, who noticed almost immediately that the nozzle was stuck on my forearm
It happened so incredibly fast, it took me a second to realize what was going on.

Of course, that was a long time ago, and I know better now - keep the body parts away from the suction.

It good you don't have to deal with - and its not just California - but many areas that have such ridiculous laws. They want to micro-manage every single thing you do. (and not just about suction dredges).

B

[dredgernz]

I tried that too...on a 2 x 9hp - 6" keene....jep...unreal power there....
should be good for....catching...SALMON....ARNOLD...the my hummerS...are...green
I will have a barre in front of the nozzle...when I start/stop ect
to prevent it from sucking itself into a JAM
But I have a flexibel hose...grey - mining abrasive type....
cheers

Don't tell anyone, but I almost got my arm broken with a 6" dredge................man that hurt. And the hose was so stiff, I couldn't get it around to cut the engine. (luckily, there was someone else there, who noticed almost immediately that the nozzle was stuck on my forearm
It happened so incredibly fast, it took me a second to realize what was going on.

Of course, that was a long time ago, and I know better now - keep the body parts away from the suction.

It good you don't have to deal with - and its not just California - but many areas that have such ridiculous laws. They want to micro-manage every single thing you do. (and not just about suction dredges).

B

[mrs.oroblanco]

I had a flexible hose, too - the problem, of course, is that flexible hose wasn't so flexible when it was full of water!!


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[Hoser John]

Ms O --ifn' ya thought that lil'ol'6" bit ya hard you should feel a 10" chomp on ya with 2 vw powered precision pumps AND a extra 50 hp precision pump for the second jet(50" of 10" hose does require a mite mo' power) We had a gent of color and I mean blacker than a moonless nite at midnight and he was white as a sheet when we peeled the hose off his back and poured the blood out of his wetsuit!! Talk about the hickie from LL!!! tons a au 2 u 2 -John

[mrs.oroblanco]

I don't think I would even want to try a 10" hose. That other one, besides hurting like a beach, left a purple and green, and black and blue mark that just did not want to go away for a few weeks. (biggest hicky I've ever seen). Plus, if it you do it just right (like I did), it will penetrate the skin, so you have a huge hicky surrounded by a circular scab. Yuk!

They sure have power - - - I can see how your "gent of color" friend got scared - you just make it worse trying to peel it off your body. The suction is very hard to break - I just cannot imagine one 4" bigger with a bigger motor. That's a BIG

It sounds funny - we even laugh about it now and then, but, at the time, it wasn't the least bit funny.

B

PS - I have to ask - how did he get it on his back?

[Hoser John]

He was moving boulders and got disorientated in 35'+ blackness and slipped and fell down with almost 75lbs a lead on because of the current in the MF American. You are absolutely right about not being funny--but the black turning white was a chuckle to see, NEVER came back to work for some reason and even left his share a gold in his haste to adios our enterprise. tons a au 2 u 2-John PS-that was the last gravel munching monster I ever ran without a reduction flap either!!!!!

[mrs.oroblanco]

Can you blame him? I don't know if I would have come back either - naw, I couldn't leave without my gold


B