Here's a green horn placer mining question.
Ah! The inquiring mind! No question too green. No answer too confusing.
If I find gold that is flat and mainly fine-grained on my claims how far has the gold traveled?
From your claims into my pocket.
If I find gold that is rough in texture, how far has it traveled.
It bounced around from pocket to pocket when I was trying to hide it.
Flat and chunky.
Musta sat on it.
Quartz attached to it.
Oops,forgot to knock the quartz off.
Wire like.
Fell off of my computer.
All distance type questions. Near to source, Far. What does shape mean?
Not much if you can't find enuff of it.
Seriously, the more filligreed and rougher the gold is, the shorted distance it is likely to have travelled. There is no telling if it has not broke off a larger chunk recently, but usually given the size of most gold, it can be divined from roughness and delicacy just how far it has come. Rough grains with lots of delicate knobs etc has travelled a short distance. Anywhere from a few hundred feet to say 3 miles. Look at the nearby hilltops, and up ice. If the gold is flattened and smoothed it may have tumbled and been dragged for a few miles, say up to 15. It could even be glacially transported. This is what bothers me about the gold of the rivers of northern Alberta as they are fairly pristine and some has quartz attached. They say it is glacial but its condition does not add up to that. Most gold in placers is local point source from nearby veins. Most Yukon gold, from which it has been difficult to divine the source, is larger, smoother, and clearly water worn. The gold in Kalimantan is clearly the same, fine, rounded, water worn grains. The gold shown in the Bre-X photos was 40 times greater in volume often than the rock shards it was supposed to have come from and water worn smooth and round. Clearly it was a fraud from the size, shape and smoothness of the grains. This was not liberated from quartz, or it would have been rough and hackly, even given the polishing effect of the crusher and grinder. The Aussie consulting company which had the photos of the ground samples from the start of the fraud was aware of this. They were bound by a confidentiality not to tell on the company, but one wonders about the limits of this sort of thing. I don't believe that the power of confidentialities makes it a necessity to conceal evident crime.
Quartz attached grains are fairly close by in source. I would say farthest is mountain top or closer.
If you find glacial till gold it may have come from as close as 100 metres and as far as 1.5 kilometres until it slopes back down to bedrock sources, or as far as 15 to 100 miles. Generally I found most Northern Ontario gold in soil was from 3 to 15 feet from the vein it came from!! any less and you are unlikely to find it in a pan. Just not concentrated enough.'
Panning sands close to bedrock is an excellent way of finding veins. It was the chief technique the Romans used and was the method of finding most of the Kirkland Lake Gold Mines.
Gold is can be flattened or rounded from stream action. If it is smoothened on the surfaces then it has travelled a ways. Generally though it could have travelled down a local mountain and then got subjected to a lot of glacial ball milling. This type of valley transport could bring gold a dozen miles or a 100. If there were lots of veins in the valley, the placer would still be good that far away.
Even in non glaciated terranes 50% of the placers in valleys are not local to source from what is apparent from cursory examination. Or the source is no completely eroded. But this leaves an astonishing half of all non glaciated placers being left sitting on gold mines. You would think this would be a major focus of gold mining companies. It is to some. However these type of "geochems" are often ignored.
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