Fine gold and bedrock question

[northern_sierras]

I prospect on a creek behind my house which contains only fine gold and got 1/4 ounce of flood gold relatively fast from a couple spots on the bank. I've only found gold on the top layers of dirt, and Im guessing the gold was placed there from the 97 flood.

Anyway the gold is only on the top 12" of dirt, and i would think after 18 years and all the snow and rain we get would have pushed it down further? How long does it take for fine gold to move further into the ground? Does gold move down faster in the stream bed than on the bank?

There is one particularly deep pool (about 6ft deep) that i assume gold would have fallen out at during the flooding. What is the best way to sample the bottom of that pool?

PS- There is very little exposed bedrock on this creek.

 

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[delnorter]

Northern Sierras, It would help to have a picture or two of the dirt your speak of and the gold. What you describe is certainly possible, just seems odd from your write up.

Mike

 

[goldandbill]

On my claim at the Sixes River in SW Oregon, I did a lot of reading on mining reports from state geologists. In some cases you might find a report on your very area. Anyway, the best gold I found was BELOW a very deep, long hole. At flood stage ( which you should observe for yourself )the water pressure decreased at the lower end of the hole as the river bed was wider. Here was where the float gold, up to nugget size was located.The geologists report said best success , at another location on the river, on low profile gravel bars was to the inside or slack water area during summer time. The best being just at and / or below the first big exposed rocks at the head of the bar. Many such rocks had just the tip above the water line.
At the time I was a newbe to dredging so I was unsure where to start. Many had suggested working up stream to keep silt and rocks out of the way. But, never one to follow exact rules, I began in the noted zone on the flowing water side and cut across at 90 degrees to the flowing water towards the bank. I figured this way I would cut the pay streak. As it happened I dropped in right on top of it and followed towards the shoreline. When I got around the big rocks I could see fine gold clinging to the moss on the down stream sides of those big rocks. This was the float gold blown out by flooding. UNDER and around the bottom of the rocks was where I found some nuggets and many pickers. See pics.
Most fine float gold doesn't have the wt./ size to end up on the bed rock, that may be why you are finding it in the first 12 in. Keep working where you find it, sample some other areas, especially below the hole.

 

[Hoser John]

The smaller the gold the longer it takes to sink to the bottom of the pile onto bedrock pay streaks. Sounds like a simple flood layer that has not been around that long geologically. Go from the bedrock and work into the creek. I know you said not much showing BUT that's what makes it all that more important. Sounds like heaven to me with a paying creek in the backyard. I've been looking for a couple of years to buy a piece of that dream but very elusive for my needs. To clean that hole all you need is a dredge and get'r done FAST-John

 

[bobw53]

and i would think after 18 years and all the snow and rain we get would have pushed it down further? How long does it take for fine gold to move further into the ground? Does gold move down faster in the stream bed than on the bank?

In my limited experience, and I also know little to nothing about water.... Something has to make the gold move... You are more dense than your mattress and you don't wake up
under your bed every morning.

Something needs to liquify the material to let the gold settle down... Water is good at liquifying stuff, dry washers use air to effectively liquify the dirt... Vibration.. tremors,
earthquakes, your mother-in-law coming to visit... That can help move it down... Otherwise its just going to sit there on the solid dirt underneath it...

Another thing to consider.. Rain and wind and maybe light flooding can wash away the light stuff over time, effectively concentrating your gold at the surface.

Where I'm digging, I've found that going deep only results in processing more dirt.. 95% of the gold is right at the very top, within 2 inches, I'm not even digging anymore,
I'm just scraping. Might be worth doing a test and processing down in layers of 2 or 3 inches at a time to find out what level the gold is at. If you keep going you may hit
a layer that was deposited in the great flood of 1922 (I just made that year up).

I have not a clue as to the in stream stuff, but if small stuff is coming down and depositing on top, there might be bigger stuff that was able to work its way down when
it had the chance.

Being right in your backyard gives you the unique opportunity to do small samples at your leisure... And really figure out what is going on.
No packing up the rig and driving a hundred miles to dig, then digging as hard and as fast as you can so that you can be at work Monday morning.

 

[RotGrub]

I prospect on a creek behind my house which contains only fine gold and got 1/4 ounce of flood gold relatively fast from a couple spots on the bank. I've only found gold on the top layers of dirt, and Im guessing the gold was placed there from the 97 flood.

Anyway the gold is only on the top 12" of dirt, and i would think after 18 years and all the snow and rain we get would have pushed it down further? How long does it take for fine gold to move further into the ground? Does gold move down faster in the stream bed than on the bank?



There is one particularly deep pool (about 6ft deep) that i assume gold would have fallen out at during the flooding. What is the best way to sample the bottom of that pool?

PS- There is very little exposed bedrock on this creek.

I would first continue to use the resources that you have. You know there is fine gold in the bank material. I would classify to 1/2 or 1/4 and pan it out. If you have running water and a sluice you will recover 10x more gold than panning. A highbanker will increase your recovery well past a river sluice and you can attach a dredge hose to sample the deeper pools. Use what you have and pay attention to the material. Look for gravel benches outside of the creek (test holes), get a mask and take a look at the bottom of the deeper pools etc... A 1/4 oz of flood gold in a short time tells me to run as much accessible material as you can with the best tools available to you!

 

[spaghettigold]

View attachment 1192995 View attachment 1192997 On my claim at the Sixes River in SW Oregon, I did a lot of reading on mining reports from state geologists. In some cases you might find a report on your very area. Anyway, the best gold I found was BELOW a very deep, long hole. At flood stage ( which you should observe for yourself )the water pressure decreased at the lower end of the hole as the river bed was wider. Here was where the float gold, up to nugget size was located.The geologists report said best success , at another location on the river, on low profile gravel bars was to the inside or slack water area during summer time. The best being just at and / or below the first big exposed rocks at the head of the bar. Many such rocks had just the tip above the water line.
At the time I was a newbe to dredging so I was unsure where to start. Many had suggested working up stream to keep silt and rocks out of the way. But, never one to follow exact rules, I began in the noted zone on the flowing water side and cut across at 90 degrees to the flowing water towards the bank. I figured this way I would cut the pay streak. As it happened I dropped in right on top of it and followed towards the shoreline. When I got around the big rocks I could see fine gold clinging to the moss on the down stream sides of those big rocks. This was the float gold blown out by flooding. UNDER and around the bottom of the rocs was where I found some nuggets and many pickers. See pics.
Most fine float gold doesn't have the wt./ size to end up on the bed rock, that may be why you are finding it in the first 12 in. Keep working where you find it, sample some other areas, especially below the hole.

Outsch!

My last trip ended before i was able to dredge up exactly that material.

 

[goldandbill]

Outsch! View attachment 1193094

My last trip ended before i was able to dredge up exactly that material.

I agree with your comment!! I am so compulsive I wouldn't have been able to leave it alone.