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JR BOI

Managing Your Rock Pile While Dredging

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So I’d like to gain some insight from the experienced dredgers on this forum about how to manage your rock pile while working.  I’m certain many of you have a few tricks up your sleeve, so I’d be interested in hearing how you manage the rock pile as you are dredging as well as placement of the dredge relative to the hole you are working.  Any insight would be appreciated.


 

 


 

JR

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Terry, with a sluice box....I find myself moving rocks underwater more than once and it feels like when I get in my dredge hole the work is harder due to the fact I'm moving rocks more than once....some of this is due to the fact that when I'm under water, I end up changing direction based on how the gravels looks once I start moving the material out.  The tailings pile isn't an issue, as my wife tends the box and keeps them clear, this is especially true if we are in shallower water.  

 

Make Sense?

 

JR

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Start off making your hole wide from the top,throw your rocks downstream behind you.I just use a small anchore tide to my dredge.When I want to adjust where I want my hose to be,nice an straight as possible.Just hafto throw the anchore in the position you want your dredge.Trying to dig straight down does make it more difficult from cave ins an haveing to throw your rocks behind you when your in a tight hole.

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Do you have a winch setup at your location? If you do, use a rock boat and the winch to haul the cobbles and small boulders far enough out of the cut so you don't have to move them twice. My first rock boat was an old wheel barrow bin. We drilled holes through the front to loop a chain through. Normally I run a three man crew, the rock man fills the boat and the winch man pulls it out of the hole. The rock man empties the cobbles and then drags it back into the hole. If I'm running solo under water, I park the boat close enough behind me so that it's an easy toss to fill the boat. If you don't have a winch, you can still use a boat, just don't fill so much that you can't drag it. This year I'm going to experiment with a small lifting bag to take some weight off the boat and make it easier to drag.

 

The trick is to move the first rocks far enough out of the hole so that they are not in the way as you work down and forward. My general rule is that no rocks will be dumped in the cut until I have reached bedrock and pushed forward several feet. The deeper the gravel, the farther away your first rocks will have to be taken.

 

It is far more efficient to make the cut much wider at the top than one would think necessary. The deeper the gravel, the wider the top cut. If you find yourself working the bottom of a hole that is only 1-2 feet across, go to the top and open the cut wider. If you're cutting straight down, you quickly become boulder bound and you'll spend hours trying to get cobbles and small boulders out. By opening up the cut, you can quickly work around those cobbles with the nozzle to free them up.

 

As far as dredge placement goes, ideally you would have a nice straight hose. In small streams that's not always doable. A single gentle curve is the next best thing.

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John, excellent insight.  I like the rock caddy idea and will work to incoporate it into our process. I've actually heard this before but haven't applied it before. Since my wife is usually tending the sluice box and helping in moving the rocks, I'll need to get creative wrt the winch idea. 

 

JR

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I dredged with a guy who used a milk crate for a rock caddy.When the crate was full I would tug on the rope and he would pull it out;dump it;then I would pull it back to me with a return rope.Seemed to me to be a lot easier than having to chunk them all by hand.

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I saw a couple of guys working the GPAA claims on Hope Creek in Alaska.  They were using the milk crate method and had a hole big enough to put my 4x4 dodge ram 2500 in.  It seemed to work well for them.

 

Trevor

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Your method of cobble removal is predicated on many things. Size of dredge,depth of water, % of material that goes up the nozzle in relation to whats left. Always keep a safe zone for your hands,fingers,toes or you will smash them. For every foot of overburden your hole must be wider by a foot for safety. Stairstep sides for boulder smash prevention.Always dredge upstream into the current to keep hole clean for visability and NEVER move a rock more than once. Crates,nets lifts,bags on and on. My favorite is chainlink fence. 4' wide-anchor 1 end and fill with cobbles,attach a winch,be it motorized or hand, and crank a whole pile outta the way. As the end folds over it holds the rock pile in place and moves it downstream outta your way nice and ez like. Then no lifting,hand hauling,stumbling and a fumbling with crates fulla knucklebusters and done MUCH less frequently. tons a au 2 u 2 -John

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One of the sweetest decisions a dredger still can make,  is this a cobble, big gravel or a small boulder?  I say a cobble is that which I can barehand downstream and see it gone from my excavation.  Boulders are in need of mechanical advantage to adjust their position.  Whichever you decide, go for the easiest, fastest and safest method.  Be cautious here because winches and tensioned cables can end your dredging career prematurely.

 

A 100lb cobble underwater ain't much of a chore if you use the current to help.  Some dredgers used to wear-out their hard working shoulders by one-handing too many heavy cobbles.

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After 50+ years a cobble,boulder and bus sized monster moving I had to have both elbows rebuilt but good to go for another 50+ at 63 YAHOO-never enough-I'll pay any price to continue to play....John

:D

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Nobody will tend my dredge for me anymore due to my rock chucking, I don't place rocks anywhere I remove then. My dredge holes are cleaner then my house. With my 4" that's a lot of tossing with the 6" not as much. Depending on how deep I am depends on where the rocks go, to get your dredge to follow you ya don't want to have to drag it over a cobble pile you made behind you or to have to move rocks to get the right angle on your jet and flare, it's a waste of time away from the nozzle. I try to pile stuff to the side and behind. Why? I fill my holes back in with it, and with the tail of the dredge in the faster water I try to avoid those big tailing piles that draw attention. IMO the faster water also helps break up that deadly flume we dredgers leave. We all have our ways that is mine. My grandfather told me to touch the same rock twice is a sin, 36 years later I still hear him saying it.

Ken

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