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 Replies: 11 / Views: 1,890 |
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Valued Member
United States
264 Posts |
... how much gold would it contain?
impurities must contain a few other interesting trace elements, right?
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Pillar of the Community
Canada
1411 Posts |
So little it wouldn't be worth refining.
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Pillar of the Community
Russian Federation
5172 Posts |
The Siberian (and later Suzun/Kolyvan mint - it has to do with the particular mine) copper coinage famously contained trace quantities of gold and silver - just barely high enough to significantly impact the theoretical melt value and just barely low enough to be not worth refining (at least at then-current tech level). I'm fairly sure that if there aren't any such stories about the copper coinage of any other countries (US, UK etc) then the price of gold thus found, if any, would be a miserable fraction of the price of copper. A ton of copper is worth $7850 apparently; so at most there'll be $500 worth of gold (i.e. a few grams). Probably less  |
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Moderator
 Australia
16817 Posts |
If the gold content of bronze cents was one part per million, then 1 (metric) tonne of coins would yield one gram of gold. Unfortunately, I haven't found any reference to anyone finding detectable levels of gold in bronze cents anywhere near that high, so typical levels are likely to be much less than 1 ppm, with a corresponding yield of much less than a gram.
If the raw copper output from a copper mine were found to have levels of gold in the 1 ppm range, the mine's owners would probably consider that to be viable to extract. They wouldn't have a "copper mine" anymore, they'd have a "copper and gold mine". The copper output from that mine would then have a much reduced gold content, having been scrubbed of gold prior to refining.
Since economically viable gold ore deposits contain roughly 1 ppm gold or more, one could say that bronze cents are a very poor (and very expensive) grade of gold ore. You'd be looking at parts per trillion (milligrams per tonne) at best.
Don't say "infinitely" when you mean "very"; otherwise, you'll have no word left when you want to talk about something really infinite. - C. S. Lewis
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Pillar of the Community
Russian Federation
5172 Posts |
I googled the Kolyvan situation; apparently their copper originally had around 100 ppm gold, and up to 1% in silver.
The smelting techniques slowly improved as to the silver, meaning in the later years there was something like 0.2% in silver; I don't know what happened with the gold though.
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Bedrock of the Community
13014 Posts |
Looks like I own some gold after all  |
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Bedrock of the Community
Australia
21786 Posts |
Gold, in finely divided form is purple, silver is black, as some of us know, with photographic negatives.
The Melbourne Mint during WW2, expended less effort than usual it the refining of metal for their bronze pennies. Occasionally, bronze pennies of the war years develop purple patina which I have long suspected, may have been the result of residual gold accentuating the resulting purplish patina on the pennies of this period.
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Valued Member
 United States
264 Posts |
Thanks for the very informative replies. I was mostly trying to point out the scarce element value of some of the copper penny hoards some of us now have. While I now agree it is minimal, I find it interesting to note that there may be some tiny amounts gold in there!  Even more intriguing is the discussion of which type of copper we would want to hoard. Besides numismatic and melt value, we now have more reason to find some WW2 Melbourne Mint copper! |
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Pillar of the Community
United States
4008 Posts |
My question is, "How much would it cost in heat to melt a ton of copper?". That alone could take a big bite out of any expected profits.
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Valued Member
United States
264 Posts |
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Pillar of the Community
United States
4008 Posts |
Solar makes it easy? But probably not very fast. As we used to say in the chemical business, "You can have fast, cheap, or good. Which 2 do you need?"  |
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Bedrock of the Community
13014 Posts |
Quote:
But probably not very fast. With any luck itd be done in time for the grand kids to sell  |
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Replies: 11 / Views: 1,890 |
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Posted 12/02/2012 4:42 pm
