Author Topic: Gravity dredging  (Read 8323 times)

samcox

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Gravity dredging
« on: August 30, 2015, 05:38:38 PM »
Many of you have dredges collecting dust. Why not coil those hoses and head to the river for some gravity dredging? As far as I know no mention of it has been made I. The states restriction so it should fall under class one equipment. With a little recon you could be silently dredging with gravity as your vacuum all you need is a hose the right amount of fall and a sluice or collection device at the down hill end. Btw I'm looking for 50 ft of good cheap hose. 2 inch preferably
my videos on youtube are under  Adventures with sam and Victoria. I have several playlist so look at the prospecting list for some goofy prospecting vids, Be blessed, and enjoy!

Chuck Pharis

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Re: Gravity dredging
« Reply #1 on: August 30, 2015, 05:43:13 PM »
We tried it at Lower Coker a few years ago. We could not get enough fall to get the water moving enough. The material stopped before it got to the end. No matter how hard we tried, we could not make it work. You really need a lot of upper to lower fall to get the material to move. After many tries, we gace up.
I hope someone else can make it work around here.
Chuck
Chuck Pharis
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samcox

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Re: Gravity dredging
« Reply #2 on: August 30, 2015, 05:46:18 PM »
A place like coker creek falls vac above and collect below.... but ideally it's what 1 foot per 10 feel so it's a limited are it'll work but find those area and it'll work.
my videos on youtube are under  Adventures with sam and Victoria. I have several playlist so look at the prospecting list for some goofy prospecting vids, Be blessed, and enjoy!

Xaero

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Re: Gravity dredging
« Reply #3 on: September 02, 2015, 03:31:21 PM »
Take a suction nozzle and have the pressure end a half mile up the falls, the business end sucking dirt, and the exit a half mile down river?

The pressure end would need to be a bucket sized opening with the hose reduced in size a couple of times before it hits the nozzle.
« Last Edit: September 02, 2015, 04:02:25 PM by Xaero »

skunkass

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Re: Gravity dredging
« Reply #4 on: September 02, 2015, 04:48:28 PM »
So. If a man could make this work. Could I use this at Little River? If so I'm on it! Lol ;D
Better to die on your feet than live on your knees......
impeach!

Chuck Pharis

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Re: Gravity dredging
« Reply #5 on: September 02, 2015, 05:51:21 PM »
You need a lot of drop to get the water to flow. There is no place at LR that would work. The material will pack up in the front end and not move.
Chuck
Chuck Pharis
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skunkass

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Re: Gravity dredging
« Reply #6 on: September 02, 2015, 10:10:02 PM »
I think with the right flare/box to catch the water and drive it. And a short suction hose it can be made to work. But not cheaply.
 I would have to start with a 4'to 5' box flare and a 4" dive/ pressure hose down to 1 1/4.  And the sluice  will not be a surface type.  ;)
Better to die on your feet than live on your knees......
impeach!

chiptrip

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Re: Gravity dredging
« Reply #7 on: September 03, 2015, 05:07:13 AM »
The elements required to perform this are very similar to a hydraulic ram pump which only has about 10% efficiency, but can produce decent head pressure.  It still requires a significant drop/slope to drive the pump as it is the weight of the water that produces the energy.  Hypothetically, I suppose one could combine such a pump with a venturi to make a very small dredge work, but I can find no reference for my assumption.

Hydraulic Ram Pump :
http://www.instructables.com/id/Hydraulic-Ram-Pump/
« Last Edit: September 03, 2015, 05:28:37 AM by chiptrip »
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Woodspirit

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Re: Gravity dredging
« Reply #8 on: September 03, 2015, 08:07:52 AM »
I think with the right flare/box to catch the water and drive it. And a short suction hose it can be made to work. But not cheaply.
 I would have to start with a 4'to 5' box flare and a 4" dive/ pressure hose down to 1 1/4.  And the sluice  will not be a surface type.  ;)

There are several drops on LR, you just have to locate them. They are called "Water Spills or Dikes". These formations are about 7' high. Attach your flare to the top section, collect the water into a 6" pipe then reduce the pipe every 10'....I think you get the idea.  ::)

Use an old discarded - deflated raft to camouflage your flare.  ;)

Now, what are the ramifications of being caught?   :-X

samcox

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Re: Gravity dredging
« Reply #9 on: September 12, 2015, 12:11:48 PM »
Gravity dredges are non motorized and the rule of fall is 1ft per 10 to get the right pressure to moveaerial well so a 50 ft jk ose needs 5 ft drop or real close to work I've seen a few vids on this and it works good around small falls of a few feet. I'm just waiting to bump into some really good hose cheap or free
my videos on youtube are under  Adventures with sam and Victoria. I have several playlist so look at the prospecting list for some goofy prospecting vids, Be blessed, and enjoy!

skunkass

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Re: Gravity dredging
« Reply #10 on: September 12, 2015, 02:18:57 PM »
Gravity dredges are non motorized and the rule of fall is 1ft per 10 to get the right pressure to moveaerial well so a 50 ft jk ose needs 5 ft drop or real close to work I've seen a few vids on this and it works good around small falls of a few feet. I'm just waiting to bump into some really good hose cheap or free

I buy mine at farmers co op.
There reasonable priced.
Better to die on your feet than live on your knees......
impeach!

chiptrip

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Re: Gravity dredging
« Reply #11 on: September 13, 2015, 08:30:23 AM »
Gravity dredges are non motorized and the rule of fall is 1ft per 10 to get the right pressure to moveaerial well so a 50 ft jk ose needs 5 ft drop or real close to work I've seen a few vids on this and it works good around small falls of a few feet. I'm just waiting to bump into some really good hose cheap or free
Sam,
  I admit that I thought your ratio was backwards until I realized you are referring to a syphon system and not a venturi (aka suction nozzle, power jet, or jet log).  It is somewhat upside down to what most folks expect.  It's not for a plunge pool so much as it is for above the "falls".

For those who may not be following:

This design, a syphon style dredge, doesn't have a venturi which is the most common dredge design.  The Idea with this is that there is single long hose that feeds directly into a sluice box.  The dredging occurs at the height of the "fall" area.  When I had a fish tank this was how I cleaned it, syphoning the water into a bucket on the ground while sucking in debris at the upper end of the hose.
« Last Edit: September 13, 2015, 08:43:50 AM by chiptrip »
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Auprospector

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Re: Gravity dredging
« Reply #12 on: September 14, 2015, 05:43:07 PM »
Yea look what we have come to. Trying anything to suck material from the bottom of a water way. I think we need to put our heads on strait. Do you really think Gold is only under water ?  Think people there has to be away while staying out of the water.

samcox

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Re: Gravity dredging
« Reply #13 on: September 18, 2015, 03:55:16 PM »
russ you are right. there is more gold out of water than in it... BUT i happen to be a fat guy who in the dog days of summer perfer the cool knee deep water to the skeeter infested woods. but when fall gets here i brave the timber for MEAT, deer meat... as winter gets here i should try some dry prospecting, but never have done it so id need a guide to teach this old worn dog the tricks of the trade... i assume your volunteering... lol... however i thing i grasvity dredge will work here local if we have the right fall... id love to run into about 50' of 2" hose i didnt have to pay an arm and leg for... Andy help a brother out!
my videos on youtube are under  Adventures with sam and Victoria. I have several playlist so look at the prospecting list for some goofy prospecting vids, Be blessed, and enjoy!

Auprospector

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Re: Gravity dredging
« Reply #14 on: September 23, 2015, 08:14:31 AM »
Forget dredging. Lets start working on dry land gold prospecting. I dont know where or how to start but someone here must. Or letd find out. Any suggestions will help.

chiptrip

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Re: Gravity dredging
« Reply #15 on: September 23, 2015, 09:53:15 AM »
A good metal detector is a place to start.
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samcox

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Re: Gravity dredging
« Reply #16 on: September 28, 2015, 02:07:13 PM »
it seems to always come back to money? a good MD is out of reach for me. I would love to have a garage full of high end prospecting gear but on my budget its low end DIY things I have to work with... Gravity dredging may be a low end winner at the right location... i will probable start with some cheap corrogated pipe if it works awesome if not i got gutter spouts that get new pipe
my videos on youtube are under  Adventures with sam and Victoria. I have several playlist so look at the prospecting list for some goofy prospecting vids, Be blessed, and enjoy!

Making Rock Soup

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Re: Gravity dredging
« Reply #17 on: September 28, 2015, 03:52:04 PM »
On metal detectors, when I looked at them price wise, they all found metal to the same depth. 
It was in coin depth specifically that the differences started.
There was only a four inch difference between the cheapest & the most expensive..
At roughly $100. for every 2 inches in coin depth you gain.

On this note, are you interested in digging deeper, for each potential find, than 5 inches for the cheapest Junior Bounty Hunter ($60.), whose rod can be carefully separated into halves, & fit inside a backpack. Almost fits whole.  Two standard "D" Batteries, & a weather resistant coil.

Or you could pay $260 and then require digging up to 9 inches for each potential coin find.   

If my memory serves me correct, the gold setting is at the least position of strength when turning it on in the first place.   I have not gotten to test mine on any gold yet.. so, if anyone has any experience or opinions I would love to hear them.

Making Rock Soup

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Re: Gravity dredging
« Reply #18 on: September 28, 2015, 03:56:54 PM »
gee, I forgot to say it Extends like an umbrella handle does.. to most any length.. It is sufficient for me to walk around using without needing to walk bent over.. but, I am only 5'3".  For a tall man, 6 foot, this option might not work out.  It does proclaim itself to be of "Professional Quality."

skunkass

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Re: Gravity dredging
« Reply #19 on: September 28, 2015, 05:32:03 PM »
On metal detectors, when I looked at them price wise, they all found metal to the same depth. 
It was in coin depth specifically that the differences started.
There was only a four inch difference between the cheapest & the most expensive..
At roughly $100. for every 2 inches in coin depth you gain.

On this note, are you interested in digging deeper, for each potential find, than 5 inches for the cheapest Junior Bounty Hunter ($60.), whose rod can be carefully separated into halves, & fit inside a backpack. Almost fits whole.  Two standard "D" Batteries, & a weather resistant coil.

Or you could pay $260 and then require digging up to 9 inches for each potential coin find.   

If my memory serves me correct, the gold setting is at the least position of strength when turning it on in the first place.   I have not gotten to test mine on any gold yet.. so, if anyone has any experience or opinions I would love to hear them.

When it comes to a metal detector there are a lot of differents in them. Depth, kHz,and VLF or p.I .
Better to die on your feet than live on your knees......
impeach!

Chuck Pharis

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Re: Gravity dredging
« Reply #20 on: September 29, 2015, 02:45:52 PM »
The depth depends greatly on the coil size and if you use a mono or DD coil.
Also soil type, soil condition, local interference, swinging speed, detector settings and what you are searching for.   
I have tested a GPX 5000 with 12" to 24" mono and DD coils. I used a pea size nugget and detected it from 1" up to 2' with different coils. Much more that the 4" difference listed in another comment.
Many have used detectors wrong for years, lose interest and sell them for much less than they bought them for.
The best way to learn how to use your detector is to tape a ring, coin or gold nugget to a piece of cardboard with a string attached to it.
Bury it at different depths in different typed of soil. Learn what each item sounds like and how deep you can go with all the different settings on your detector.
All detectors are NOT made alike.
Chuck Pharis
Chuck Pharis
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Making Rock Soup

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Re: Gravity dredging
« Reply #21 on: October 23, 2015, 09:47:37 PM »
Nice comments guys, thanks!