Water table?

[someday]

Gday all.
I came across a gravel wash in a straight section of creek! My first thought was a previous prospector created the wash, now I'm confused "Doesn't take much"

At right angles to the creek and this wash, there's a boggy section of ground on about a 25 deg going up 100 or so meter high hill!

The wash intrigued me, so about 30 meters up this hill and before the boggy ground starts, I got stuck into diggen a sample hole!

Typical 100mm of topsoil, then hard packed gravel, Test panned the gravel an sure enough, fine gold, nothen new there, so keep on diggen, when I got to the 2 foot mark, the ground turned to blackish clay, and then it was all over, the next downward pound with me crowbar, the crowbar ripped through me hands on it's way to China?? If it wasn't for the nobly bit on the end I'm sure I would've lost the bugger.

So I suppose my question is, Has anyone seen or have theory's with gravel deposits washing out from a water table!
Not even sure it's possible, but it's the only idea that makes sense to me

Cheers
Chris.

[rc62burke]

Hi Chris
Gravel Wash in a straight section? what exactly do you mean gravel wash? is it totally different to the rest of the creek?
After the blackish clay what is the composision of the stuff before you get to China, I'm thinking you've got yourself a deep lead, old water course thats why it's boggy.
cheers
Lee

[donnybrook]

Not sure where you are from but I have also found gemstones in such material which does or can form a deep lead.
donny

[someday]

Gday Lee and Donny.

I'm prospecting around the Beechworth area, so fine gold and deep leads were pretty much the norm!

The gravel wash is predominately ruff quartz with a pool of water on the upstream side of the wash. This quartz wash wouldn't be more than 20 foot long, running parallel to the creek and at right angles to the bogy ground!
The creek at this spot is about 15 foot wide and less than 2 foot deep with bugger all fall to it, which makes me think there should be a lot more water, considering the creeks water feed rises into steep country for about another 5 k's??

I was running me highbanker about 200 meters down stream from this spot, fine gold was in the surface gravel and every gravel/flood layer to a depth of no more than 2 feet, then clay then no more gold, More black sand than you can poke a stick at!

Cheers
Chris.

[gold]

it sounds like what you're describing is water seeping out of an old buried stream bed that has been cut through by the current day stream ?

[someday]

Thinken of knocken up some screw together metal rods to see how deep me test hole was goen to go! an if I hit a Chinaman up the butt I'l know I spent to much on metal rods ;D

[rc62burke]

Hey Chris
Hey watch out those Chinese will copy your screw together rod thingy if you get close enough.
cheers
Lee

[someday]

There's always a pit fall. Bit of lube, make it quick an easy ;D

[kel]

The boggy ground may be an old drive that has been filled with ground water and mud ofer the years or it may be the outfall of a deep lead or it may just be a spring. There could be a few explanations for the wash where it is. A sluicing claim on the hill above may have been losing more gold than they knew about, a chinaman may have tripped over and spilled his poverty pot, etc etc.

The wash being on top of the bog suggests that it may be shedding from above the source of ground water for example a false bottom or ancient flood deposit above the bedrock wash layer in a deap lead - the water following the bedrock and seeping out at the upper area of the bog.

Test pan samples in an organised pattern around and within the boggy area - the more the merrier, record the results as you go. A long tube of wrapping plastic with string tied around it to separate your samples, to carry them to the creek - in a backpack. Pan one shovelful at each spot. Record for example specs per pan and be meticulous. Analyse the results and you will observe how the gold is moving and from where. You can follow the source to where it is shedding and attack it with your highbanker.

A deap lead is still a water course even if 100 feet below because it is based upon bedrock or hard clay. If you believe the gold is shedding from the boggy area, go to the furthest uphill bit of wet ground, where it starts to dry and probe down at a slight angle (perpendicular to the ground if a 25 degree slope) into the slope with a small auger on a shaft. Take samples every 6" until you hit bedrock (may be a fair way so auger shaft needs to be screw joined - only ever turn one direction so it doesn't get dropped). If bedrock is only a metre or 2 under and shows good prospects from sampling then dig. Be careful to step or support the wall of the dig to prevent collapse from the wet ground. There is a limit to how far you can go without an exploration or mining license.

Disclaimer: Alluvial mining is very dangerous please be aware of the risks before doing this type of work. The authorities frown upon major disturbance so it is better to go about it the legal way than to do illegal mining.

kel.

[someday]

Thanks for the reply Kel.

The quartz wash/gravel bar is within the stream on a straight! the end of the bog at right angles is about 40 meters away and at a guess, about 20 foot higher sloping down to the water level.

Sorry guys, a picture would tell a thousand words, O well.

The fact that answers and info is hard to come by is probably a good thing ;D more test holes required

Cheers
Chris.

[someday]

Well I'm over the water table thingy me 65mm hand auger down to a depth of 17 feet an not a rock to stop it
I always thought the hills are there due to bed rock avoiding erosion?

New plan, dig a trench where I know there's good gold in the flood layers and put some dirt through me sluice

Cheers, to much turning
Chris

[backcreek]

Hay Chris,
17 feet!!!!! wow that's an epic effort mate.
Have you sample panned any of the material from the auger tailing's to see if it's payable?
Might be worth a look!

Cheers
Mick

[someday]

G'day Mick

Yep every 10 inch's, pull the auger out an pan , small quantity of fine gold in the first 2 feet, never got richer! small specks of gold each time, but you gottu think about contaminating the next sample each time yu lower the auger in the hole an pull it out! No doubt it's a lead / gutter, still would of thought of rocks getten in the way of me small auger, wasn't to be?? 4 holes in total .
Wifeys wonderen what I get up to when I go out ;D

[kel]

That's a good effort Chris, you are a patient fellow. It's a bit easier with an auger than a shovel and at least you now know the potential of the lead. I find a 40mm auger dodges the boulders but still gives a good sample. You will find good use for your auger particularly if bedrock is within reach. Have you ever wondered what gold is in that "salt and pepper" bank wash or did that ground sluicing claim stop on gold? The auger lets you find out

To "calibrate" your auger samples - for want of better words, take a full pan from where your first sample was and compare the number of specs with your smaller auger sample. Only the gravel directly off the end 6" of the auger is relevant for a sample. Therefore a small amount of gold specs in your small sample can indicate a good leader. I have found this to be so in the past sampling flood channels on Reedy Creek.

This technique is not as good for nuggety country as there might be 10 or 15 pieces in a few grams of gold from a tonne of wash - too easy to miss with a small sample.

Like you have seen some gold is not worth the effort and I don't bother any more if it is deeper than a metre.

Good luck and may the gold be with you.