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thegoldgopher
08-29-2012, 10:01 AM
I have diving experience, but none in gold dredging. I have used air lifts up to 24" diameter, and jet nozzles for underwater excavations, and they are basically exactly like the gold dredge nozzles.

I know in streams, the channels are narrow, and the spaces between boulders and stuff are a hindrance, but I'm talking about the open flat ocean floor type of dredging.

I watch the underwater diving footages, and it seems like there could be a little better way of excavating the area around the nozzle. Maybe some rebar to penetrate and stir up and dig up a slightly bigger area right there at the entry. Even a crowbar on a rope to help dig right under the intake. I always think, "Geez, maybe just another inch, and they'd get that golf ball sized nugget, but now they will never know."

I read a golf article that said the greens are where a golf game is won or lost. A very good golf player may be able to drive a long way, lay up a good approach, or even get to the green, but they then take 3 - 4 - 5 strokes to sink the ball. It seems that way with gold dredging, that a lot of time and work and thought goes into finding just the spot they want to look for a pay streak. But then, they just skim off the top 6 inches of an area of about fifty square feet. Why don't they concentrate more on heading straight down until they hit hardpan or bedrock.

Just wondering. Seems like the gold would have settled deeper than the top six inches. They keep sweeping the head, and I'd like to just let it eat a hole to China, and be lazy and watch it, let gravity help out, and clear rocks and impedences to its going deeper. If I was big and fat and lazy and old and in bad health, I'd make a davit crane or knuckleboom, make a heavy shaft shaped head, and sit topside in a Herculon recliner in a heated room, and just lift and lower and move the tip of the device until it stopped descending, then move it a foot or three over.

Fill me in. e mail inquiries welcomed

Steve

carter
08-29-2012, 11:56 AM
This is my first season with a 6" dredge. All the books tell you to find the bottom of hardpack. My bedrock is shallow 1-3ft. but i do find paths of clay layers and hardpack sitting on top of the bedrock. My swivel nozzle has the reducer ring welded on it and have noticed it is pretty much useless in hardpack so i am going to build a ring that clamps on the end with a hi-torque hose clamp that has short spikes on it similar to a toughdog collar. Being able to swivel that back and forth will be way more efficient than having a prybar or chipping hammer under water.

Bill Bohan
08-29-2012, 12:01 PM
Time consumed, fatigue, and ripped dive gloves results in digging deeper. In some creeks the shallow gravels might contain more of the gold and the gravels lower grades down to bed rock.

In the case of my current prospect pit, I have a three foot wide fissure vein that I am working. A mineralized zone of three foot wide is beneath the vein as the vein dips at an angle. I free gold up and quarts pods containing finer gold in the mineralized zone. The zone I am harvesting become more rock hardened the deeper I go....till it becomes futile. My time is better spent working a surface area. That way I can process the above placer and the "permobedrock" or rotted bedrock.

thegoldgopher
09-01-2012, 09:05 AM
I just watched another Bering Sea Gold with the guys diving under the ice. One team barely had any devices on the end of the nozzle to keep large rocks from going in there. Well, there was a round grapefruit sized rock that went in there and shut down the whole operation. How difficult is it to weld a piece of rebar across the openeing to keep out rocks that are going to shut you down?

IdahoHick
09-01-2012, 02:08 PM
And on top of that... Why isn't there a rockhammer or small garden claw(three of four tine) on a leather(shoelace,breakable) on divers wrist,? or tetherd to a lead weight and small light reflecting float in area being worked?? Just thinking some tools would take some wear and tear of the gloves... Raking the bottom in front of the suction intake I think would help? A guy could even hook the larger cobbles and huck them out to the side....I myself am thinking if a Pitchfork and roundpoint shovel had little short "D" handled Pitchshovel babies....LOL I'd want one, big rocks out gold falls through slots or holes with a vigorous shaking, or a giant strainer spoon on a shovel handle. Anchor the dredge intake and strain the biggies out in front then back for the smalls. Sure I could make one and probably will. "V"

geowizard
09-01-2012, 03:41 PM
thegoldgopher,

RE: The plugged suction hose problem...

You're right. I drilled two opposing 3/8 inch holes in the nozzle of my six inch, cut a 7 inch piece of 3/8 inch all-thread. put it through the holes and put a couple of lock nuts on the ends.

- Geowizard

overtheedge
09-01-2012, 04:52 PM
I use a D-handled garden spading fork for breaking up the armor layer. Mine has 1-5/8" gaps between the heavy duty tines.

1/4" gravel plant screen over the 2" nozzle, but it clogs with roots, etc that get eroded off the bank from upstream. Gold is all smaller than about 1.6mm (1/16").
eric

thegoldgopher
09-02-2012, 06:13 AM
This is my first season with a 6" dredge. All the books tell you to find the bottom of hardpack. My bedrock is shallow 1-3ft. but i do find paths of clay layers and hardpack sitting on top of the bedrock. My swivel nozzle has the reducer ring welded on it and have noticed it is pretty much useless in hardpack so i am going to build a ring that clamps on the end with a hi-torque hose clamp that has short spikes on it similar to a toughdog collar. Being able to swivel that back and forth will be way more efficient than having a prybar or chipping hammer under water. I am working on an idea that will improve the amount of material that can be agitated for the suction nozzle to pick up. I will be working on it through the winter. Please file my e mail addy, and contact me, or watch for further notice of this product. What I see in the way of how dredge heads work does not impress me, unless they have motorized cutters. For the average simple vacuum dredge head operator, things haven't changed any in the last 100 years.