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Author Topic: Coal with Gold deposits embedded  (Read 17106 times)

Offline miaoux

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Coal with Gold deposits embedded
« on: 30/04/2006 14:09:41 »
Hi all,

I have a query that hopefully one of you will have the answer to =)
One of my friends (interesting character) has a coal mine out nr. Malaysia, and he informs me that he's recently discovered thermal coal in the mines with deposits/veins of gold running through the coal.

Would this be caused by fluke sedimentation / a gold deposit nearby (that has somehow melted into the coal?) or is there another reasonable explanation?  

It's kind of funny, because he wants to sell the coal, but he can't burn it to extract the gold ('waste' of coal), and he can't exactly sell the coal with 'free gold'.  Nor really sell the gold with 'free coal'.



 

Offline Ophiolite

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Re: Coal with Gold deposits embedded
« Reply #1 on: 30/04/2006 14:31:01 »
I am not sure what you mean by thermal coal. Can you clarify please.

It wouldn't take much gold to make mining the coal for the gold economically viable. Gold concentrations in commercial deposits are typically very low.

I am having trouble envisaging a mechanism for getting the gold into the coal. You have identified the two most probable causes.

Fluke sedimentation: I would think it would have to be quite a fluke. Coal is typically deposited in a delta environment far away from source rocks. Sedimentary gold gets concentrated in placer deposits relatively close to source. It's just the wrong mix of parameters. Not impossible, but incredibly unlikely, I think.

Hydrothermal veining: if there is an igneous intrusion nearby (within a few miles) then it is possible gold bearing fluids could have percolated through the sediments, depositing gold in the coal. This is more likely than the first option, but still very unusual.

Are you absolutely sure it is gold? Could it not be iron pyrites, also known, for obvious reasons, as 'Fool's Gold'? This is not uncommon in coal.

Observe; collate; conjecture; analyse; hypothesise; test; validate; theorise. Repeat until complete.
 

Offline Bass

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Re: Coal with Gold deposits embedded
« Reply #2 on: 04/05/2006 00:55:18 »
miaoux-
gold is not uncommon in coal deposits, most coal deposits contain gold above average crustal abundance.  In fact, many gold mines recover gold using heap leach technology.  The gold is taken into solution using a cyanide solution, and is then scavenged from the pregnant solution with activated charcoal.  Usually the gold is disseminated throughout the coal, not found in veins.
My guess is that these are later hydrothermal veins- the gold my be deposited in veins in the coal due to favorable geochemical conditions.  Do the veins extend into the country-rock surrounding the coal?  If so, then the gold is almost certainly hydrothermal in origin.
Gold is recovered from carbon all the time by refiners- the process is not difficult.

Subduction causes orogeny.
 

Offline miaoux

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Re: Coal with Gold deposits embedded
« Reply #3 on: 09/05/2006 01:51:16 »
Thanks for the answers
 

Offline miaoux

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Re: Coal with Gold deposits embedded
« Reply #4 on: 09/05/2006 01:53:00 »
oops -

Thanks for the answers both - erm, I'm not sure if the gold extends further - apparently they only noticed the gold veins after they wiped/cleaned some of the coal and noticed the gleaming.  I still don't know if it's iron pyrites yet =)  Will update when I get new info =)
 

Offline Vadermort

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Re: Coal with Gold deposits embedded
« Reply #5 on: 15/05/2006 03:04:33 »
Few years ago I obtained a sample of volcanic mud from Sakhalinsk, an island off the east Russian coast. It contains cubic metallic crystalls inside the soft mud. Havent done much on it but i am pretty sure its iron pyrite. any way to test it other than hardness?
I will try to get a picture soon.


b.s
 

Offline Bass

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Re: Coal with Gold deposits embedded
« Reply #6 on: 15/05/2006 16:54:11 »
Cubic metallic crystals suggest pyrite- but can you give us a better description (color, size, striations, streak, etc)?

Subduction causes orogeny.
 

Offline bkcaffee

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Re: Coal with Gold deposits embedded
« Reply #7 on: 10/10/2006 17:06:13 »
i also found gold veins in coal about the size of a softball it was in a creek. i found it by luck. would it be worth going back and looking more.
 

Offline bkcaffee

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Re: Coal with Gold deposits embedded
« Reply #8 on: 10/10/2006 17:07:56 »
i also found gold veins in coal about the size of a softball it was in a creek. i found it by luck. would it be worth going back and looking more.
 

Offline Bass

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Re: Coal with Gold deposits embedded
« Reply #9 on: 10/10/2006 18:31:16 »
Are you sure it was gold?  Could it possibly be pyrite (fools gold)?

If it is indeed gold, than YES, I sould investigate further and see if you could find the source.  May I ask what part of the US you are from (and the area you found the gold/coal)?

Subduction causes orogeny.
 

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Re: Coal with Gold deposits embedded
« Reply #9 on: 10/10/2006 18:31:16 »

 

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