The Gold of Fort Knox

Fort Knox Bullion Depository: one of the most secure areas in the entire United States. It’s also one of the largest collections of bullion in the entire world, and it all belongs to the United States. Only the Federal Reserve Bank in New York holds more gold, some of which is in trust for foreign nations, central banks, and official international organizations.
The United States didn’t always have such a large bullion depository. It wasn’t until 1933, when President Franklin D. Roosevelt outlawed the private ownership of gold coins, bullion, and certificates by Americans. This forced them to sell their gold to the Federal Reserve, which suddenly had a large amount of gold with no place to store it. In 1936, The United States Bullion Depository at Fort Knox was built.

The amount of gold at Fort Knox has varied over the years. However, it has been many years since gold has been transferred into or out of the facility. Currently, Fort Knox holds 4,578 metric tons of gold, or according to our pennyweight conversion calculator, 2,946,000,000 pennyweights. According to estimates from the World Gold Council, that’s approximately 2.5% of all the gold ever mined across the globe. According to this month’s gold prices, the gold in Fort Knox is worth about $182.6 billion dollars. That’s a lot of gold!

Image By Cliff [CC BY 2.0], via Wikimedia Commons

How the World’s Gold Reserves are Protected

Nearly 25% of the world’s gold is stored at the Federal Reserve Bank of New York. While the unparalleled reliability of the Federal Reserve is a compelling reason for foreign governments to store their gold reserves there, there is another interesting reason: unmatched security systems.
It takes a combination of highly trained individuals and top-notch technology to protect all of that gold. First off, the Reserve employs its own security force and rigorously trains them throughout the year. Not only do they have to memorize extensive security procedures, but they must also maintain a marksmanship certification badge twice per year for handguns, shotguns, and rifles. Certification badges have three levels: marksman, sharpshooter, and expert. Although the Federal Reserve only requires a marksman level score, nearly all of the security employees maintain an expert qualification in all three weapon types. With just the security team alone, the gold is already well-protected.

Technology and vault-design add even more security for the gold reserves. Not only are there the to-be-expected cameras, alarms, and locks (which must be deactivated by several people – no one person knows all the combinations), but the vault itself can only be accessed via a 90-ton revolving steel cylinder. If anything is tripped, guards are signaled to seal the entire building – which takes less than 25 seconds.

The bank is so secure that hardly anyone requests to inspect their gold. But if they do, they have to plan ahead. Once a request is made, it takes a whole day to get through all of the time and combination locks!

How Gold Sluices Work

From the earliest gold rushes to the present day, the sluice box has remained a staple tool for prospectors and placer miners. Despite advancements in engineering over the years, gold sluices have changed very little since they first became popular – after all, “if it ain’t broke, don’t fix it!” This is due in part to the solid design philosophy that gold sluices are based on.

While early prospectors were panning for alluvial gold, they soon noticed that the best places to search were the inside bends of rivers and creeks; in natural hollows and rock crevices; and at the base of escarpments, waterfalls, or other minor impediments to the water’s flow. What all these areas have in common is that they accumulate gold by “catching” it as it flows past while dirt and gravel are pushed further on by the current. This happens because the gold is heavier and harder for the current to push. In the lab, this process is called “gravity separation.”

Sluice boxes are designed to mimic this naturally occurring gravity separation. As water carries gold-laden sediment through the box, small obstructions called riffles block the free flow of material. These tiny flow restrictions form low pressure pockets where the gold collects.
Sluices are an effective tool for collecting gold, but they don’t work without water. They can also miss gold if the water flow through the box is not carefully regulated. If you want to learn more about how sluice boxes are used to find gold, check out our infographic below.