gravity dredging in washington?

[Ragnor]

So the way I read the rules it says suction dredging. No real differentiation on motorized equipment vs gravity feed that I found. But at the same time apparently gold suckers are allowed. Which are of course hand suction devices. So does anyone know for certain where the gravity dredging technique falls? I know I could just write and ask WDFW, but they always want more information than I want to give them. So I'm asking on here.

Beyond that. With gravity dredging. Could you use rigid pipe for the top end over the hump and then switch to layflat on the down hill run? That would save allot on weight and cost if it would work.

 

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[MadJack_ME]

This year will be our 4th year using mostly gravity here in Maine.
Lay-flat will not work, period. You CAN use hard pipe joined with 2' pieces of old dredge hose but stream conditions will dictate what you can get away with more than anything.
We just use an old (thick & heavy) Varco? 4" and thread it down through the rocks, keeping it as straight as we can.
We have 2 - 35' sections plus the stinger/nozzle from my 4"... and we leave it there year 'round along with an old crash-box dredge sluice.
(out of sight of the stream)
Priming is a P.I.T.A. some days, but clogs & jams in the hose must be found and cleared quickly or you will lose your prime fast.
Also it would be best to start with fresh/new hose as ANY tiny crack-split-damaged section will suck air and frustrate the hell out of you!

We get ours started-primed by using a plumbers plug at the bottom end, then gulp water in at the top until full. Then release the plug and slip it on the flare/crashbox. No gas, no noise for people to track down, NICE!

 

[MadJack_ME]

 

[russau]

SWEET!!!

 

[ratled]

First off are we talking siphon style or true gravity? spaghetti gold here does siphon style. Think of it as siphoning gas out of the tank. The issues that needs to be over come this way is having enough drop in a short enough run that you can the material.

True gravity is where you use a traditional dredge with a jet or suction nozzle and have a enough drop (head pressure) to power the jet/SN. That is easier said than done short of a water fall. The New 49ers have been working on it for the last 2 years and were finally able to get it to work some. It took over 500' of hose to get far enough up the hill to start to get enough pressure to work. You can get the jet/SN to work at lower pressures but it is not enough to create enough suction to move gravel. At medium pressure you develop enough suction to move material but at not enough to keep the hose clear fast enough and you get plug up hell.

Once you get the right spot to get either to work then you have to find a similar spot that will work just as well AND have gold there.

ratled

 

[Hoser John]

EZ to do--keep it simple and forget jets-John

 

[mike(swWash)]

In Washington if it's in river season then dredge by whatever means you want according to pump and nozzle size allowed, otherwise no sucking, digging or scooping from the in water area.

 

[Ragnor]

In Washington if it's in river season then dredge by whatever means you want according to pump and nozzle size allowed, otherwise no sucking, digging or scooping from the in water area.

Ahh ok, they kind of got me from a couple of directions on that one then. Thanks

 

[Ragnor]

First off are we talking siphon style or true gravity? spaghetti gold here does siphon style. Think of it as siphoning gas out of the tank. The issues that needs to be over come this way is having enough drop in a short enough run that you can the material.

True gravity is where you use a traditional dredge with a jet or suction nozzle and have a enough drop (head pressure) to power the jet/SN. That is easier said than done short of a water fall. The New 49ers have been working on it for the last 2 years and were finally able to get it to work some. It took over 500' of hose to get far enough up the hill to start to get enough pressure to work. You can get the jet/SN to work at lower pressures but it is not enough to create enough suction to move gravel. At medium pressure you develop enough suction to move material but at not enough to keep the hose clear fast enough and you get plug up hell.

Once you get the right spot to get either to work then you have to find a similar spot that will work just as well AND have gold there.

ratled

Yeah, I was thinking on siphoning. I did the math on actual gravity dredging last summer and by the time you get enough drop you are at high risk of blowing the side out of a layflat hose.

 

[russau]

Years back George "Buzzard" Massie did a segment of him high banking and got his water from a mine shaft above him and he used PVC pipe and he noted that you always turn the valve on / off (for water) very slowly or you will burst the pipe or valve. That is a habit I got into doing when operating BIG compressors. I'd rather be safe than sorry!

 

[kcm]

He was getting some very impressive pressure as I recall. But I must confess, had forgotten all about that show until you mentioned it.

Have wanted for years to get ahold of some of his shows, but just can't seem to find them anywhere.

 

[Hoser John]

Layflat does not work as must be rigid to suck.....John