Suggestions for surveying area, 3 to 5 feet under sand?

Boarteats

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Mar 25, 2018
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Not even sure what to google for this question. :)

Anyone have good suggestions for sampling around an area at a depth of 3 to 5 feet under sand, gravel, rocks? Must be a better way to do this than with pick axe and shovel. I'm just a hobbyist and the area is pretty isolated, so all tools are hand carried or hauled in wheelbarrow.

Background:

Prospected an interesting steam (with owner's permission). Not much on stream bed, but area has lots of iron oxides and the such, so I decided to dig down to see if I could find a clay layer where gold could be collecting. Bedrock is waaaaaay too far down. Sure enough, found a nicely dense layer of clay under the sand at a depth of 3, maybe 4 feet. Pretty good gold from that first test hole. Now, I want more test holes.

Results from first hole.

https://drive.google.com/file/d/151zNAUkjeyr8AOtDmMNO09tMvB5X_qqC/view?usp=drivesdk
 

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Goldwasher

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churn drill or auger
 

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Boarteats

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@goldwasher ...hrmmmm. might be able to rent a small posthole digger/auger. Depends on how heavy they are, I suppose.

@imaudigger, suction dredge was a good suggestion. Unfortunately, not enough water in stream for a dredge. Not much to the stream unless its raining. As it is, I need to use a small bilge pump to get enough water flow for a tiny 24in sluice.

Thx!
 

Goldwasher

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May 26, 2009
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Sailor Flat, Ca.
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SDC2300, Gold Bug 2 Burlap, fish oil, .35 gallons of water per minute.
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@goldwasher ...hrmmmm. might be able to rent a small posthole digger/auger. Depends on how heavy they are, I suppose.

@imaudigger, suction dredge was a good suggestion. Unfortunately, not enough water in stream for a dredge. Not much to the stream unless its raining. As it is, I need to use a small bilge pump to get enough water flow for a tiny 24in sluice.

Thx!

They have cheap ones at Harbor freight
 

russau

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May 29, 2005
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@goldwasher ...hrmmmm. might be able to rent a small posthole digger/auger. Depends on how heavy they are, I suppose.

@imaudigger, suction dredge was a good suggestion. Unfortunately, not enough water in stream for a dredge. Not much to the stream unless its raining. As it is, I need to use a small bilge pump to get enough water flow for a tiny 24in sluice.

Thx!
If water supply isnt close try one of Chuck Lassiter's dry land suction nozzel.s pump the water on hand to the hole and suck it out as water suppy will deliver !
 

mikep691

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Auger is easiest to test. If you know the bedrock is close, then maybe dam the creek where you want to work, let it fill. Then dredge it out. When you run out of water, take a beer break while it fills back up
My kinda mining :occasion14:
 

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Boarteats

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Auger is easiest to test. If you know the bedrock is close, then maybe dam the creek where you want to work, let it fill. Then dredge it out. When you run out of water, take a beer break while it fills back up
My kinda mining :occasion14:

Don’t know how far bedrock is. Only place nearby where depth was measured (that I’m aware of), bedrock was about 100ft down, I believe. Some guy actually tried to mine the bedrock at that depth at turn of 20th century but went broke! Had good gold but cost too much to extract it. However, my stream is right on boundary between Piedmont Plateau and Atlantic plane, so bedrock could be closer. Hard to say. I’ve been targeting hard pack layer that is only a few feet down.
 

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Boarteats

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Mar 25, 2018
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If water supply isnt close try one of Chuck Lassiter's dry land suction nozzel.s pump the water on hand to the hole and suck it out as water suppy will deliver !

I’d love to try out a suction dredge. Unfortunately, I’m not sufficiently handy to build my own. Too much $$ to buy one. I’d probably need a 4 inch nozzle given dense gravel/cobble. It’d be much faster than current approach.... guessing mikep691’s idea to damn stream could work.
 

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mikep691

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Watch craigslist for smaller one. Like a 2' combo. I can move 2-3 yards of creek gravel with mine in 8 hours. That includes beer breaks and rock rolling. But my creek never runs dry. In your case, anything bigger might be overkill when you have to wait for the water. Go a little smaller, work a little longer in spurts, and have fun.
 

seafox

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Gold washer beat me to what I was going to sugest and I got a boost when boarteets said he got one and it worked . a friend had sugest a power auger and I was wondering if you drill several holes at about twice the diamiter of the auger center to center will that break up the ground enough ( maybe sticking a big pry bar down the holds and busting through to the next hole?) to make digging easyer the damming up the creek you would think would catch enough water especally if you do it down hill from where you are mining then you wpould be recurculating the water that you have.
 

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Boarteats

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Mar 25, 2018
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...I was wondering if you drill several holes at about twice the diamiter of the auger center to center will that break up the ground enough ( maybe sticking a big pry bar down the holds and busting through to the next hole?) to make digging easyer the damming up the creek you would think would catch enough water especally if you do it down hill from where you are mining then you wpould be recurculating the water that you have.

In general, I've augered a couple holes next to each other. Once I get through packed rock/clay layer, it's pretty easy to expand access with shovel. I use a bilge pump to move water where I need it, which has been adequate for the 24in sluice that have. I've found it necessary to classify material down to pretty small size before sluicing it. I use same bilge pump to wash material through classifiers into bucket. I use a Falcon MD20 to examine larger rocks.

Suction dredge would make process much faster but can't justify cost to buy one and haven't been successful in attempts to build a diy version. Think that I'd need a better pump to make it work. Unfortunately, I live on east coast. Haven't found any used suction dredges on craigslist.
 

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