alluvial gold in streams and sediment transport

[Scottish888]

Hello from Scotland,
I am trying to understand how gold moves in high stream flows.
Have you ever cleaned out an area of a stream then returned later to the same spot and found gold there?
The area I go panning can sometimes have 8 people within a 100m length and manytimes, no one so I can't rely on other human activity not affecting gold movement along/around streams.
Maybe you have an isolated claim that you can be assured no one else panning affects it.
The stream I pan is mostly shallow (welly boots are fine to use) and an average width of 1m but in floods it can move 50 kg boulders and cover the meander areas with boulder and stone debris,flooding to 10 m wide in areas, it can be a very high energy environment.
How far do you find or think gold moves in streams?

Regards,

 

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[et1955]

You asked a very hard question and there is no one answer to for your situation, so many variables to consider. For me when considering floods and there deposition of gold depends on Hight and duration. Some floods will flush out the gold and others will deposit gold. How far will the gold flow, only the river knows but that is the great mystery and one you could solve by testing after a flood but the best time to analyze deposition is to be there during a flood. I don,t know about your stream but here where I live all rivers are monitored for their levels so I can monitor them for possible gold deposition. Sadly for my area there has not been a good gold depositing flood since late 1995, hundred year floods happen rarely but since I was there during that flood I was able to see and understand why and where the gold was deposited, I am still mining those flood deposits. Best Wishes

 

[Scottish888]

Thanks for your reply,
It is a difficult question but with enough collective information it could be understood a little better.
I am also thinking about when rivers flow a little faster and higher depth (but not crazy flooding) has that left gold in a previous cleaned up part of the river bed.
I may set up an experiment in the stream stretch using 50 lead replacement airgun pellets, seed across the width of the stream and ask panners to leave a stick in the bank saying where found.
I would use the sediment transport channels at work to run experiments but they are too narrow to allow me to put in a representative rock size so I could not rely on that.
We know gold is unevenly distributed in the alluvium and sorting will have been carried our where ancient streams interact with that but trying to figure anything out is very difficult, maybe impossible

 

[et1955]

That is what is different about your mining situation, you are trying to analyze a small little stream, I have watched videos of a guy mining in your area so I do understand what you are dealing with. Here in Washington State the rivers I mine are different, mainly a lot bigger, after over 45 years mining on them I found the secrete to what type of flood will deposit gold or strip it out. A flood that goes high and then slowly goes down and we are talking over a month recede, a flood that goes up high fast and then recedes fast is stripper. As an example I was mining a gravel bar on the Sultan river before the Historic flood and sluicing I found just over 1/4 lb. of gold and the big long flood happened , after it receded I went back there the bar was stripped but funny thing is all the gold that was there was moved down river to the next bar, I am still mining that place and so far just over a lb. from this one bar and there is a lot more there, Have fun

 

[Scottish888]

Thanks,
All info helps, I agreee that fast and high floods seem to strip from one location then distribute it further downstream.
One of our usual good spots is often cleaned out after winter storm floods, it also undercuts some of the alluvial banking letting non pay gravel/dirt fall into the stream from higher up but over a couple of months gold grains seem to find their way down from the wet alluvium...or are they being transported from further upstream under normal flow conditions.
It is interesting and likely impossible to work out just how far gold travels under different situations.