How 99.99% Pure Gold Is Made | Inside a Modern Gold Refinery

[00:00:00]This is how gold becomes one of the world's most valuable assets, >> [music] >> and almost none of it starts the way people think. Before it's traded, hoarded, or turned into coins, it has to survive a journey through industrial hell, crushing machines, cyanide baths, molten metal, and electrolysis. But to really understand the process, you've got to start at the source, because before gold is ever refined, it has to be found. And it must be pretty rare, right? According to the US Geological Survey, all the gold in the world mined since the dawn of recorded history is small enough to fit into a cube roughly 22 m, 72 ft, on each side. But to understand gold, you first need to know where it starts. That's right here in the mine. Mining is an intense, hard process. There are three different methods. Each has its challenges. Open pit mining is the oldest form of mining.

[00:00:51]Since this mining takes place near the surface, it doesn't need deep shafts.

[00:00:55]There's Modern mining is done with heavy machinery, like these bulldozers and trucks.

[00:01:01]It's the cheapest and least risky form of it, but that doesn't mean it's safe work. The pits can collapse, which is why they need stepped sides or benches.

[00:01:11]There's another problem. As you can see, these pits take up a lot of space, and they can severely disrupt the local ecosystem and communities. Also, most surface resources have been used up by now, which means mines typically need to go deeper. That's where underground mining comes in. Underground mines typically look like this. And just looking at it might make you nervous.

[00:01:35]Fortunately, the work is more automated than it used to be. More on that soon.

[00:01:41]Underground mining goes through two main stages. First, there's development, which removes rocks and other interfering components that don't have any value. When that's done, the miners can proceed to production mining, where the target resource, gold in this case, is excavated from the rock. Before any resources are taken, a coal seam or ore body examination must be used to figure out the exact deposit location. Mining is expensive and this saves unnecessary work. Plus, it helps to prevent cave-ins. Other measures are taken to secure underground mines. Take a look at this. These are hoses blowing crushed limestone dust on the mine's walls.

[00:02:15]They're called rock dusters and the dusty walls don't catch fire as easily.

[00:02:19]Then there are these roof bolters, which secure the mine's ceiling with safety jacks. Hydraulic machines force bolts into the roofs.

[00:02:27]This is done as another way to prevent collapse.

[00:02:32]Then there are the shotcrete machines like these that spray the walls with a wet mixture to reinforce structural integrity.

[00:02:40]There are also new helpers, drones that can inspect place that would be dangerous for humans to go. The trucks, drills, and excavators you're seeing is are also controlled remotely to make things safer. Now production mining can begin. If underground mining makes you too nervous though, this is the type of stuff you might have seen in movies. It involves rinsing and sifting unconsolidated minerals mixed with sediments.

[00:03:04]Placer mining is the simplest, but if you want to do it, you'll need to extensively survey the target area to figure out how much stuff is really there and whether there's enough recoverable gold to sustain the operation. If there is higher concentrations of sediment, you'll need to do more to recover the gold. It helps to remember that most people in the California gold rush went bust. A typical gold mine will last for 10 to 30 years. During those years, the long laborious process of extraction will typically transform rock and ore into a metallic alloy that's between 60 and 90% pure.

[00:03:36]But that's still not good enough. The gold bars you're seeing at the US Mint didn't come fresh from the mine, so what's next?

[00:03:44]>> They have to go through here first, the gold mill.

[00:03:47]There's a lot of heat and chemicals to be found here to say the least.

[00:03:51]>> Without them, you'd never see those shiny gold bars because even if it comes 90% pure from the mine, there are still substantial impurities in the ore. Look at these people, they look like they're shaving something. This is the first step for many sources of gold. It's through a process of size reduction such as shedding or grinding, which increases the surface area for the other phases of processing. It also helps to further break apart the gold from the material it's lumped in with. It also helps to further break apart the gold from the material it's lumped in with. After that, there are a few ways to go. One thing you can try if you're refining gold is cyanidation.

[00:04:32]This chemical dissolves the gold from the impurities, but it's a controversial practice. Cyanide is a highly toxic chemical and there have been accidental spills. Billions of gallons of cyanide contaminated water have been released into the environment since the 1970s, which you might have guessed from seeing these kinds of pictures. Thankfully, there are other methods like mechanical separation. This method makes use of gravity, fluid, or centrifugal forces.

[00:04:55]For example, watch this centrifuge spin.

[00:04:58]The ore in a centrifugal force field is composed of particles with different densities, which means they move differently under this force. The heavier, valuable metal naturally isolates itself from the useless rock.

[00:05:08]Spin it enough times and they'll naturally separate from each other.

[00:05:11]There it is, it's since gold has a much higher density than the more common minerals it's lumped in with, it's easier to recover. But that's still not enough to create those gold There's another refining step that's needed for almost total purity.

[00:05:27]Let's taste. These beautiful gold bars are over 99% pure and at least some of them were once electrified. When you think of electrolysis, you use it in stingers, but it's just as good at making the gold you actually do want.

[00:05:39][music] Electrolysis is the process where an electrical current flows between two elect In gold refining, hydrochloric acid serves the electrolyte.

[00:05:51]Gold alloy makes for the anode, the positively charged electrode, while the cathode, [music] the negatively one, is typically a thin sheet of high-purity gold.

[00:06:00]>> The current between them ionizes the electrolyte, which increases the purity to 99.9%.

[00:06:07]>> This is called the Wohlwill process. If you're okay with settling for slightly less purity, like decimal points less, you can try a different method, the Miller process. It uses something you're probably more familiar with from a homework assignment you did back in school.

[00:06:24]If you paid attention in history class, you'll recall the horrific use of chlorine gas in World War I.

[00:06:30]Fortunately, there's a better way. The Miller process uses chlorine gas to pass through molten gold, just like this.

[00:06:37]The gas triggers a chemical reaction that separates remaining impurities, which precipitate to the surface in the form of chloride and are then removed.

[00:06:46]Treatment takes about 90 minutes.

[00:06:56]But, that's still not the end of the journey.

[00:06:58]It's about to get hot in here, for the second time if your gold went through the Miller process.

[00:07:04]You've probably seen movies where molten steel is poured into molds to make swords. It's the same with gold. These guys are pouring gold into bars. They have to be careful and wear protective clothing. The molten material is extremely hot. Gold needs to be 1,947° F to melt or 1,064° C to be in a liquid state.

[00:07:25]These workers have to pour slowly and move it with shovels and huge pliers, which, as you can see, isn't always easy.

[00:07:34]They have still more to do.

[00:07:44]If the bar meets those standards, it will be stamped with a serial number and certification mark, ready to go out into the world at last.

[00:07:52]But that gold might not go out as a bar.

[00:07:54]Still more fire could be waiting for it.

[00:07:57]These are the gold coins coming from the US Mint. They're legal tender under the Gold Bullion Coin Act of 1985, but it's a long journey to get them. The Mint buys gold bars from the open market and does its own process of verifying the purity and authenticity of each one.

[00:08:12]Once the gold passes this test, the Mint melts and alloys them to its exact specifications. 91.67% gold, 3% silver, and 5.33% copper. The gold is at a durable 22 carats. Once weighed, the coins are then shaped into blanks, blank [music] discs ready for their final designs. Then they go through the same striking process you saw in our earlier video about how money is printed. Once the job is done, they're ready to be shipped to authorized dealers. But you might be wondering, why go to all this trouble in the first place? Is tech about to disrupt gold like it's done to so many other things? Gold has been prized since ancient times for its beauty, and it's still seen as a good source of value, particularly as a bet against the sort of inflation we've all been dealing with.

[00:08:56]Governments stockpile gold.

[00:08:59]The United States has a bigger reserve than any other country.

[00:09:03]>> At 8,133.46 tons, >> [music] >> worth 683.73 billion dollars.

[00:09:12]>> The Denver Mint and the West Point Bullion Depository. The gold standard might be long gone, but America's reserve is still a hedge against economic turbulence >> and helps to solidify its place at the center of the world's financial system.

[00:09:23][music] But is that about to end?

[00:09:26]Some people think cryptocurrency.

[00:09:28]>> The Bank of Singapore said so, too. But gold has two things that cryptocurrencies and other digital assets don't. Scarcity and a physical presence. You can't just create gold on a computer screen, at least not yet.

[00:09:39]Also, there's a lot of fraud. Gold is heavily regulated, and when you buy it, you can be pretty certain about what you're getting. But crypto markets have been increasingly hit by meme coins and scams in recent years. But gold will always be valuable, not just for its beauty, but for its industrial uses, which is why it remains one of the world's most trusted investments. Just look at all the trouble we still go through to get it.

[00:10:02]Bye for now.