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  #1  
Old 10-27-2011, 03:32 PM
dolphinboy dolphinboy is offline
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Are there still large undiscovered gold deposits?

I was reading how much gold has been found so far, around 10 billion ounces. This estimate can be found here.

"To get at some kind of estimate, let's figure that the world has been producing gold at 50 million ounces a year for 200 years. That number is probably a little high, but when you figure that the Aztecs and the Egyptians produced a fair amount of gold for a long time, it's probably not too far off. Fifty million ounces * 200 years = 10 billion ounces."

Given how much gold has already been found and mined, and that 50 million ounces are being recovered each year, do we know how much gold has yet to be found? And more to the point, how likely is it that there are large undiscovered gold deposits in the world? For example under the oceans or in Antarctica?

What about in North America? How likely is it that there are large deposits that were not found during the numerous gold rushes that have occurred to date?
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  #2  
Old 10-28-2011, 02:23 AM
Measure for Measure Measure for Measure is offline
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Reverse the question. If there are gold deposits which are entirely buried 30 feet below the surface, how likely are they to be found?
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  #3  
Old 10-28-2011, 03:26 AM
Sage Rat Sage Rat is online now
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Supposedly, there's about 230 trillion kilograms of gold in the ocean. The 'discovery' would be finding a way to extract it cost effectively.
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  #4  
Old 10-28-2011, 04:23 AM
mac_bolan00 mac_bolan00 is offline
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while i was in mining in 80s-90s, annual gold prodution in the free world (ex- USSR and china) was 350-450 tonnes with south africa accounting for around 200 tonnes. before 1985, annual production was much less than this. before 1985, encyclopaedias estimated 50,000 tonnes mined since the man learned to pan and prospect. the boom in 1985 accelerated extraction, with better methods (among them, use of activated carbon and heap leaching methods.) so 1985-2010 may have extracted another 12,500 tonnes. that's 62,000 tonnes updated. but russia's output was considerable even back in the soviet era so 62,000 is a bit on the low side. even then, 150,000 tonnes seems big.

to answer your question, much of the earth's land surface has been explored either through direct field observation and drilling or remote sensing. the challenge is sub-surface exploration of "blind" deposits. very few blind deposits have been discovered. usually they were discovered only through to extension exploration work of existing underground mines. i would say there are still a lot of buried plutons with little or no surface expressions, which could harbor large mineralizations or deposits.
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Old 10-28-2011, 06:21 AM
Der Trihs Der Trihs is offline
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According to Wikipedia:

Quote:
Because the Earth was molten when it was just formed, almost all of the gold present on Earth sank into the core. Most of the gold that is present today in the Earth's crust and mantle was delivered to Earth by asteroid impacts during the late heavy bombardment.
So technically speaking we've yet to discover most of the gold on Earth; good luck finding a way to get it out of the core though.
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Old 10-28-2011, 08:54 AM
Sailboat Sailboat is offline
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good luck finding a way to get it out of the core though.
Simple, we'll just hire action heroes.
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Old 10-28-2011, 09:02 AM
WordMan WordMan is offline
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Simple, we'll just hire action heroes.
Make mine Hilary Swank, please.
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  #8  
Old 10-28-2011, 09:13 AM
ralph124c ralph124c is offline
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There are several new gold mining operations in Greenland.
How likely is Greenland to have big deposits of precious metals?
Greenland incorporates some of the oldest rocks on the planet-is it likely that there is a lot of metallic ores there?
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  #9  
Old 10-28-2011, 10:16 AM
Gary T Gary T is online now
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Are there still large undiscovered gold deposits?

If they're undiscovered, how would we know whether or not they exist?
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  #10  
Old 10-28-2011, 12:40 PM
dolphinboy dolphinboy is offline
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Originally Posted by Gary T View Post
Are there still large undiscovered gold deposits?

If they're undiscovered, how would we know whether or not they exist?
Fair point.

We might know based on the fact that you would expect X amount of gold based on the geology of a particular region. Since they have only found Y amount then presumably there is an X-Y amount somewhere waiting to be found, or perhaps never found. I am not a geologist, buy presumably there are geologic markers that tip off the presence of gold, e.g. a certain type of quartz formation. I also assume that all of the obvious places to look for gold have already been checked in North America during the various gold rushes, however this assumption may be totally bogus.

So can we say with any certainty that the chances of finding a large surface deposit of gold in North America is slim to none, or could there be rich areas that just haven't been adequately explored yet?
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  #11  
Old 10-28-2011, 01:13 PM
yabob yabob is offline
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meteorites and people:

http://www.webelements.com/gold/geology.html

I'd WAG that the meteorite content may be similar to core rocks in the Earth. Note that it's still a pretty low concentration - 170 ppb by weight. The gold which was delivered by meteorite strike to the Earth's crust was also concentrated in certain places by geologic processes such as alluvial deposition.

Maybe you want to explore the fact that humans, and probably other organisms, concentrate gold (in the lymph nodes and adrenal gland apparently). Presumably some organisms do it greater extents.
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  #12  
Old 10-28-2011, 03:10 PM
GreasyJack GreasyJack is offline
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It might be worth noting that there's probably no more undiscovered placer gold fields out there. Placer gold deposits are the highest concentration gold deposits found in the Earth's crust, but are only found at or very near the surface. This is because they are found in stream sediments, which have been density-sorted by surface geology processes. The processes that will turn these sediments into sedimentary rocks will leech out and disperse the gold, so placer deposits are only found in unconsolidated sediments at the surface.

Placer gold fields were what fueled the historic gold rushes because some of them have such high gold content that it could be worth someone's time working them with primitive hand tools. Contrary to what the term means in polite conversation, the "mother lode" (the ore body which is the source of the placer gold) was almost always much lower concentration than the placer gold. And "hitting the mother lode" meant the gold rush was effectively over for the small prospectors, who had to give way for industrial mining efforts.

So, with regards to the OP, there's probably not going to be any new gold discoveries that send people up to the hills with pickaxes and pans. But it's also unlikely there will be discoveries that are rich enough and easy to extract enough that they'll have the huge effect on the gold market that the old gold rushes did. There's already lots of places on earth (even in the US) where there is still recoverable gold in the ground, but it stays there because no mining company has decided it's worth the expense and risk of developing it. Lots of them would be economic at today's prices, but most mining companies don't want to bet on those sticking around. Now, if new mining technologies make it so it's cheaper to extract some of those undeveloped deposits, that could have a more profound effect on the market.
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  #13  
Old 10-28-2011, 03:20 PM
septimus septimus is offline
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Originally Posted by Sage Rat View Post
Supposedly, there's about 230 trillion kilograms of gold in the ocean. The 'discovery' would be finding a way to extract it cost effectively.
I've always thought bio-engineers "should" design some sort of plankton with a special affinity for metals.
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Old 10-28-2011, 05:45 PM
Fish Cheer Fish Cheer is offline
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Originally Posted by mac_bolan00 View Post
the free world (ex- USSR and china)
Sorry, what?
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  #15  
Old 10-28-2011, 09:46 PM
Consensus Consensus is offline
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Read somewhere that if you could extract all the gold from the earths core we'd all be standing ankle deep in liquid gold.
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  #16  
Old 10-28-2011, 10:58 PM
Civil Guy Civil Guy is offline
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Read somewhere that if you could extract all the gold from the earths core we'd all be standing ankle deep in liquid gold.
Erm, that seems like it would be uncomfortable. Are all the sofas taken? Maybe a bench somewhere - on a hot-air balloon, maybe?
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  #17  
Old 10-29-2011, 12:09 AM
Measure for Measure Measure for Measure is offline
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Quote:
Originally Posted by GreasyJack View Post
It might be worth noting that there's probably no more undiscovered placer gold fields out there. Placer gold deposits are the highest concentration gold deposits found in the Earth's crust, but are only found at or very near the surface. This is because they are found in stream sediments, which have been density-sorted by surface geology processes. The processes that will turn these sediments into sedimentary rocks will leech out and disperse the gold, so placer deposits are only found in unconsolidated sediments at the surface.

....Contrary to what the term means in polite conversation, the "mother lode" (the ore body which is the source of the placer gold) was almost always much lower concentration than the placer gold. And "hitting the mother lode" meant the gold rush was effectively over for the small prospectors, who had to give way for industrial mining efforts.
Thanks for your informed post. Given the discussion in this thread, I would think there might be a decent chance of finds in Antarctica. It had tropical weather 65 million years ago after all and even had a temperate forest as recent as 3 million years. So the land has been exposed to nonarctic geologic processes for quite a while.
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  #18  
Old 10-29-2011, 12:35 AM
Bearflag70 Bearflag70 is offline
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Did they find gold at the bottom of the Sacramento River Delta and/or at the bottom of San Pablo Bay?
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  #19  
Old 10-29-2011, 12:39 AM
TriPolar TriPolar is offline
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The Gold Rush guys are at it again on the Discovery Channel. They found about $20,000 worth of gold last year, obviously at a cost greater than that. Even if the gold fairy tells you where $1,000,000 worth of gold is buried deep underground somewhere, you have to be able to get it out for less than $1,000,000 to make it worth bothering. And even then you are relying on the honesty and accuracy of a gold fairy.
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Old 10-29-2011, 03:47 AM
Malacandra Malacandra is online now
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Originally Posted by Civil Guy View Post
Erm, that seems like it would be uncomfortable. Are all the sofas taken? Maybe a bench somewhere - on a hot-air balloon, maybe?
That wouldn't help. Simple bench, the reason is obvious. Hot air balloon, you're going to be short of lift when the ambient air temp is so high.
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  #21  
Old 10-30-2011, 08:10 AM
Lust4Life Lust4Life is offline
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Originally Posted by Measure for Measure View Post
Thanks for your informed post. Given the discussion in this thread, I would think there might be a decent chance of finds in Antarctica. It had tropical weather 65 million years ago after all and even had a temperate forest as recent as 3 million years. So the land has been exposed to nonarctic geologic processes for quite a while.


I believe mining in Antartica is banned by international treaty.
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Old 10-30-2011, 08:14 AM
Fish Cheer Fish Cheer is offline
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I believe mining in Antartica is banned by international treaty.
At least until 2048.
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  #23  
Old 10-30-2011, 08:38 AM
wolfman wolfman is offline
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There are a few places where gold is known, but not in high enough concentration to be profitable.

In Colorado a while ago they decided to reinvigorate some old nearly dead mining towns. There wasn't a whole lot of space in the narrow mountain valley, so they had to move a bunch of dirt for casinos and hotels. There was a decent bidding war for the rights to carry the dirt away. Because mining for mining sake wasn't expected to be worth it, but as long as someone else was bringing machines up and dumping dirt on you truck for you(not to mention all the lawyering and paperwork costs) it was good money to sort through it for gold and silver.
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  #24  
Old 10-30-2011, 09:32 AM
Chefguy Chefguy is offline
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Gold deposits continue to be discovered in Alaska. The Pebble Mine project, which is meeting with considerable opposition, was more or less identified back in the 1980s, but additional potential continued to be identified as recently as 2010 (from Wiki, bolding mine):

Quote:
In 1992 Pebble was estimated to contain 3 million tonnes of copper and 11 million ounces of gold in 1 billion tonnes of ore.
In 2004 Northern Dynasty had outlined, through additional drilling, over 4 billion tonnes of ore, none of it in the yet undiscovered "Pebble East."

Estimates in February 2008 indicated: Pebble West contains (at a copper-equivalent cut-off of 0.30%) Measured and Indicated Resources of 18.8 billion pounds of copper, 31.3 million ounces of gold, and 265 million pounds of molybdenum, contained within 3026 million tonnes of ore and Inferred Resources of 5.9 billion pounds of copper, 9.1 million ounces of gold, and 993 million pounds of molybdenum contained within 1130 million tonnes of ore.;[11]

Pebble East contains (at a copper-equivalent cut-off of 0.6%) Inferred resources of 49 billion pounds of copper, 45 million ounces of gold, and 2.8 billion pounds of molybdenum contained within 3860 million tonnes of ore.[8]

In February 2010 an updated resource estimate was released reporting that, based on a total of 509 drillholes and at a 0.30% copper equivalent cutoff (CuEQ), the Pebble deposit mineral resources (East and West combined) comprise: 5.94 billion tonnes of ore as Measured and Indicated Mineral Resources grading 0.78% CuEQ, containing 55 billion pounds of copper, 67 million ounces of gold and 3.3 billion pounds of molybdenum; and 4.84 billion tonnes of ore as Inferred Mineral Resources grading 0.53% CuEQ, containing 25.6 billion pounds of copper, 40.4 million ounces of gold and 2.3 billion pounds of molybdenum.[24]
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  #25  
Old 10-30-2011, 10:04 AM
Attack from the 3rd dimension Attack from the 3rd dimension is offline
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Originally Posted by Sage Rat View Post
Supposedly, there's about 230 trillion kilograms of gold in the ocean. The 'discovery' would be finding a way to extract it cost effectively.
Quote:
Originally Posted by septimus View Post
I've always thought bio-engineers "should" design some sort of plankton with a special affinity for metals.
Estimates of gold, as well as other metals, in seawater have dropped precipitously since the 70s, as clean techniques have replaced methods with a lot of contamination. Nowadays an oceanographer attempting to measure metals in seawater uses special lines, sampling equipment and a clean-room-style lab space. Seawater is not going to produce significant amounts of gold anytime soon.
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  #26  
Old 10-30-2011, 11:32 AM
Chimera Chimera is offline
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Lots of it mixed in with other stuff here and there.

The Flambeau Mine near Ladysmith Wisconsin produced 160,000 tons of Copper, 330,000 ounces of Silver and 33,000 ounces of Gold during it's 4 year lifespan (1993-1997).

They're looking at some mixed metal mining in northern Minnesota, deposits that were previously not economically viable, and those deposits contain very small amounts of Gold in with the Copper, Nickel, Paladium and other metals.
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