It's not uncommon to see ARIS reports detailing work programs where prospectors try to find the hard rock source of the placer gold in a given area.
To accomplish this, they might take soil, silt, moss and or rock samples which are then assayed, and the results are analyzed for gold and indicator elements e.g. silver, arsenic, antimony, etc.
The assay data reveals ppb or ppm values for specific elements, which certainly provides important information.
However, these results are often disappointing for the teams that did the work.
They get perplexed by the fact that their limited sampling program around a placer stream did not reveal the source of the gold, when it's quite possible that the source of the gold has been pulverized, eroded and washed away by heavy flows, leaving gold and heavy minerals.
Assuming there is free-milling gold present that is visible under a 10X loupe or microscope, shouldn't these prospectors be examining the gold particles under magnification to learn more about the following:
Gold particles (number)
Gold size (mesh)
Gold character (rough, angular, wiry vs rounded and flat)
Gold travel distance (close to source vs far from source)
Gold inclusions (e.g. iron)
Gold alloys (e.g. electrum)
Gold ppb values on their own tell you nothing about the above attributes, which is crazy because this information can tell you a lot about a deposit.
Also, gold ppb values for hard rock can be inflated due to glacial till containing gold particles, but one cannot deduce this without examining the gold particles themselves to see how far they have travelled from source.
It seems like visual examination of gold particles might be a missing piece for these smaller exploration programs in the past.
When funds aren't available for assaying (e.g. for a solo prospector), the 10X loupe and microscope can be powerful weapons in the grassroots prospector's arsenal.
Personally, for hard rock, I prefer to pan samples where possible: soil, crushed rock, etc, and examine the panned concentrates, and any gold particles under magnification. This provides immediate information for $0 that can guide future exploration strategies (geochemistry, geophysics, drilling, etc).
Perhaps I'm missing something here. If yes, please let me know.
-Pickaxe
sebo liked this thread
I so agree with all this !!
The look of the gold is so crutial to see how far it has travelled ...
For example in mission creek in kelowna the gold is well rounded most of the time and looks "well travelled" but if you find the "old glacial channels" that pop out of the hills on the north side of the creek you can find some reall chunky/textured pieces that seem to have not travlled that far ..
.From this I believe some of the gold in mission creek comes from across the lake from the white elephant and blue hawk showings area where there is confirmed VG in the hard rock ....
Now that being said , there seems to be 2 colours of gold you find there and it is said the old columbia channel that they mined up on top of the wood lake area is also feeding the creek , which with normal testing ,without looking at the gold would be hard to decifer .
Ive heard rumors/opinions that this old Columbia channel runs down in Rock Creek as well as the gold there can be very similiar... which makes you think that there must be other places/creeks between the two sites that must have good gold somewhere..Lets not forget the Mclean's lost mine that is meantioned by bill barlee in hos episodes about the area
With spring here I guess it's time to start digging and searching for the next big find :)
Hope everyone has a good prospecting season
pickaxe liked this reply
I can see hours of fireside conversation about this stuff, so much to discuss.
So many grass roots hard rock exploration programs take some soils, get shitty values back, and call it a day thinking the area sucks for gold. In reality, did they pan or take silts or stream sediments up the drainages, taking samples where every sub-drainage comes in to try to narrow down potential source(s)?
Note: I'm not talking about Shawn Ryan style regional recon where teams gather thousands of soils, that is a different ball game.
It just seems like so much data is being left on the table by grass roots teams who rely on assay values alone.
Why not get to know the actual gold itself under magnification? All it requires is a pan, careful technique and a 10X loupe.
My step dad is a retired geologist, and I don't think he has ever taken a dolly pot, crushed down some material, and panned it for free-milling gold.
That is surprising to me.
-Pickaxe
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