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Prospecting for gold by looking in leaves has proven itself in Australia (economist.com)
75 points by pseudolus 33 days ago | hide | past | web | favorite | 45 comments

A good friend of mine is a geologist working in lithium exploration, and has found measuring samples from termite mounds to be a good indicator of what will be found by doing a much more expensive drill.

Prospecting for natural resources is a global lottery: The largest oil field in Mexico was found by a fisherman who noticed noticed slicks on his boat back in the 70s.

It took world class geologists to characterize/pull it out, though. And I think Pemex gave him a cushy lifetime job too!

Doesn't the deposit have to be close to the surface though? No deeper than ground water flows.

I'm disappointed they collected the leaves by hand. I thought the article was going to say they can measure the gold-content in leaves using drone imagery

Yeah, same. I thought they would be using satellite imagery. Archaeologists have found Mayan ruins that way because the ruins have a ton of lime plaster and the trees growing above them absorb it the same way. The leaves of the trees above the ruins reflect specific frequencies differently than the other surrounding trees and you can see blotches where the ruins are in the images (when shifted into the visible spectrum). I always wondered if you could find other things that way.

From memory, this is how Gina Rhineheart's (Australia's mining magnate) father discovered the location for the Pilbara (the world's largest iron deposit) -- by flying overhead and noticing how red the soil was[1].

[1]: https://en.wikipedia.org/wiki/Lang_Hancock

Similar techniques for viking sites in canada.

They are detecting 4 parts per billion gold content in the leaves; I don't think we are close to having the technology to detect that from a satellite. Reading another article it looks like they used the Australian Synchatron (x-ray).

"Marmota" is spanish for groundhog and is also used as a non-insulting synonym word for dumb.

There's nothing dumb about this approach, thought.

There is animal called a "marmot" in English that are large squirrels [0]. Groundhogs are part of that family, "Groundhog, woodchuck, or whistlepig, M. monax found in most of North America" [1].

[0] https://en.wikipedia.org/wiki/Marmot

[1] https://en.wikipedia.org/wiki/Marmot#Subgenera_and_species

Fascinating approach, I wonder if many other things could be tested for in this way.

I wonder if this can be useful for say, lithium prospecting?

Zizee in this post claims yes.

For everyone who gets hit with the paywall:


Interesting article

Thank you, but I’m also curious how that’s legal

It's not, it's an obvious violation of copyright. Outline.com's primary use case is pirating paid-for content.

They have a whitelist of domains they support, and they intentionally implement support for paywalled sites.

They're just not big enough yet to where large publishers have started to go after them.

I see, thanks for clarifying.

I hit the paywall and before I realized it I thought "well this is short and to the point." Duh... cool concept though

Why do we need to mine for gold in 2019?

Because the metal is used in gold-plated contacts, it's as easy as that. That is a problem, because unlike jewellery gold, gold in electronic equipment is not recycled.

Gold in electronic equipment is not generally recycled because it's cheaper to mine it. Gold might seem expensive, but you can put a ceiling on its price by thinking about what it would cost to reprocess phones in bulk. Currently tens of dollars per phone, for dollars worth of gold. Increase the price of gold, or recover some other valuable materials, and it becomes economically viable.

Gold is absolutely worth recovering from consumer electronics, as is copper and a bunch of other stuff. It's not necessarily worth collecting, but there are plenty of huge piles of e-waste lying around the globe.


One problem with gold recycling is that some simple methods are also phenomenally harmful to both workers and the environment, as they involve dissolving the gold with mercury. From what I've read, some of this stuff gets shipped to countries with relatively weak labor and environmental laws.

Simple fact, Mercury does not dissolve gold. It amalgamates with certain metals making them easier to collect in one mass rather than having tiny bits all over the place. Mercury use has very little to do with gold mining or recovery today. Repeat: I said it's used very little- not that it is never used. Its much easier and more economical to just use aqua regia to get the gold away from the base metals. Gold recovery from electronics is done in semi- laboratory conditions and the gold is refined using the same conditions which are a far cry from some guy in the hills digging up dirt and spilling his waste into a mountain stream. Modern refiners shun Hg. It's hard to clean up the waste to acceptable levels. That's a big deal nowadays. No one wants to poison the environment. Acid based extraction techniques are much cleaner,easier and more environmentally friendly. Just like everything else- it comes down to profits and it's just more profitable to use acids instead of Mercury. Hell it's even more profitable to use cyanide to extract the gold. I know a little bit about this stuff- AMA?

The mercury used in that process is generally recycled in a closed loop; if it's done properly, dangerous levels don't get into the workers or the environment. Metallic mercury is the least dangerous form of mercury, less toxic even than the ores mercury is mined from.

Unfortunately with high gold prices it becomes profitable to run small operations that don't meet the same standards. Currently it is believed that 1/3 of all mercury pollution comes from illegal gold mining [0].


But it's often not done properly, which is there are quangos and NGOs trying to get people to move to different methods of gold extraction.

UN: https://www.youtube.com/watch?v=WUY4CV50VQo

You're right that mercury metal isn't a such a big problem. The problem is that people are heating it and breathing the vapours.

I recently donated old electronic equipment to Tokyo city government. Their plan is to recycle for gold, silver and bronze medals at next year's Olympics. I don't expect it's an economic decision, but it feels good.


Old electronic equipment is the good stuff. The older it is- the better. The manufacturers have now created methods to use less gold. Equipment from the 60s is coveted. Mainframes and old giant mechanical printers have lots of gold in them. Telcom equipment, Rf equipment same thing- lots of easily accessible Noble metals. Today's scrap electronics have much less recovery value but it's still profitable, even in California. If you follow the correct formulas( developed in the 1800s and not a secret) the waste products from this process are not classified as hazardous. Yes it takes time for your reactions to complete but, it's not like you have to babysit this stuff. All the waste is converted into non hazardous elements easily thru cheap effective chemical reactions. I've said too much already but, if anyone can get ahold of a large quantity of cellphones or better yet older electronics from the past century I'd be glad to help you recover your gold thru environmentally legal methods that aren't a secret but are just not well known. Hit me up in my profile

Gold is recovered from modern electronic equipment by many people in the USA in a profitable and environmentally clean way. You don't hear much about it due to the people doing it don't want to advertise thier success. Modern electronics have much less gold or other valuable metals in them nowadays but wherever you see an electronics recycling event there are modern day gold miners. The key word here is " Gold refining"

Except that an order of magnitude more gold is mined[0] than used in electronics[1].

[0] https://www.gold.org/about-gold/gold-supply/gold-mining/how-... [1] https://www.statista.com/statistics/299603/gold-demand-by-se...

When was the last time you've seen gold plated USB cables?

Gold plating contacts may have been necessary with analog back in the day, but today's digital equipment is much more reliable thanks to error checking / correcting protocols, and other improvements. Besides, gold contacts wear out faster.

Here's a basic brand and a respected brand both using gold plating.

Amazon basics: https://www.amazon.co.uk/AmazonBasics-Male-B-Male-Cable-Feet...

Anker: https://www.amazon.co.uk/Anker-2-Pack-Nylon-Braided-Tangle-F...

First time I see this, thanks!

Unnecessary if you ask me... It's more like jewellery rather than a cable :-)

Zinc / aluminium is probably a better combination for USB, as it's more durable.

Other metals like the ones you named have an oxidation problem over time. Gold does not have that problem and contacts will wear thru thier plating by mechanical usage . Gold does not oxidize in the normal earth atmosphere. That's why you can see ancient gold in for instance : Egyptian relics that still shine - no oxidation.. It's nearly a perfect electrical conductor. There are better ( for the pedantic chemists here) But gold plated connectors are used by industry for reliability

I doubt we will be using USB 3.0 cables 5000 years later. Lol!

Perhaps for non technical reasons.

Tons on ebay (though their search is somewhat broken)


I guess they'd hold up better in a damp environment.

This reminded me of gold leaf used for cooking:


I bought 2 sheets ($0.99) out of curiosity. They are so thin and fragile that they ball-up with the slightest "breeze".

Because some people want to buy it, and it’s cheaper to mine than to transmute or sift through sea water.

Need? The only thing that's necessary in life is death. Under currently prevailing circumstances, often money is useful for postponing death, and mining gold is a way to get money.

Who said money doesn't grow on trees?


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