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?
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.
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?
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?
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.
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.
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.
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.
