Real Assets
Visualizing the Size of Mine Tailings
Visualizing the Size of Mine Tailings
On January 25th, 2019, a 10-meter tall wave traveling 120 km/h, washed 10 million m3 of mining waste from the Brumadinho tailings dam over the Brazilian countryside killing somewhere between 270 and 320 people.
This was a manmade disaster, made from mining the materials we use daily. Every copper wire in your house, steel frame in an EV, or any modern appliance comes from mining.
Mining leaves behind waste in the form of tailings stored in dams or ponds around the world. This infographic takes a look at the estimated size of one part of this waste, tailings, visualized next to the skyline of New York City as a benchmark.
Quantifying Mining’s Material Impact
In the wake of the Brumadinho tailings failure, the International Council on Mining and Metals (ICMM) began a review with institutional investors and the United Nations Environment Programme (UNEP), to survey tailings facilities around the world.
The Global Tailings Review tracked a total of 1,743 unique facilities containing 44,540,000,000 m3 of tailings. This dataset represents only 30.2% of global commodity production.
However, the review estimated the total number of active, inactive, and closed facilities is around 8,500. If we use the assumptions for the 1,743 estimate to calculate for the 8,500 facilities, a total of 217,330,652,000 m3 of tailings are in storage globally.
What are Tailings?
Not all rock that comes out of the ground is metal. Miners find, remove, and refine rocks that carry a small amount of metal we need.
According to the USGS, 72 billion tonnes of material produced just over 10 billion tonnes of ore. Only 14% mined material makes it to processing for metals.
| Waste rock (tonnes) | Material Sent to Mill (tonnes) | Ore Produced (tonnes) | Tailings (tonnes) |
|---|---|---|---|
| 72,000,000,000 | 18,800,000,000 | 10,180,000,000 | 8,850,000,000 |
Tailings are what is left over after mills separate the metal from the mined rock. The processed material “tailings” comes from the “tail” end of a mining mill and comprise fine particles mixed with water forming a slurry. Mining companies will store this waste in dams or ponds.
Not All Minerals Are Equal: Tailings Contribution by Commodity
Not all minerals are equal in their contribution to tailings. The grade, quantity, and the process to extract the valuable metals affect each metal’s material impact.
| Mineral | % Contribution to Global Tailings |
|---|---|
| Copper | 46% |
| Gold | 21% |
| Iron | 9% |
| Coal | 8% |
| Phosphate | 4% |
| Lead and Zinc | 3% |
| Nickel | 2% |
| Platinum Group Elements | 1% |
| Bauxite | 1% |
| Uranium | <1% |
| Chromium | <1% |
| Molybdenum | <1% |
| Tin | <1% |
| Vanadium | <1% |
| Manganese | <1% |
| Niobium | <1% |
| Rare Earths | <1% |
| Lithium | <1% |
| Other minerals | 1% |
| Total | 100% |
A renewable future will be mineral intensive and will inevitably produce more mining waste, but growing awareness around mining’s true cost will force companies to minimize and make the most of their waste.
Turning a Liability into an Asset
While tailings are waste, they are not useless. Researchers know there remains economic value in tailings. Natural Resources Canada estimated that there is $10B in total metal value in Canadian gold mining waste.
Rio Tinto has produced borates from a mine in the Mojave Desert which has left behind more than 90 years’ worth of tailings. The company was probing the tailings for gold and discovered lithium at a concentration higher than other U.S. projects under development.
According to UBC’s Bradshaw Initiative for Minerals and Mining professor Greg Dipple, the mining industry could help society store carbon. For over a decade, he has researched a process in which tailings naturally draws CO₂ from the air and traps it in tailings.
A Material World
While the majority of mining companies manage tailing dams safely, the issue of the material impacts of mining on Earth remains.
Mining of metal has grown on average by 2.7% a year since the 1970s, and will continue to grow. The importance of the size of tailings is critical to address proactively, before it comes rushing through the front door, as it did in Brazil.
Real Assets
How Much Gold is in Fort Knox?
The United States Bullion Depository holds more than half of the Treasury’s $428B in gold reserves.
How Much Gold Is in Fort Knox?
This was originally posted on our Voronoi app. Download the app for free on iOS or Android and discover incredible data-driven charts from a variety of trusted sources.
U.S. President Donald Trump has promised to visit Fort Knox “to make sure the gold is there.”
Officially, the United States Bullion Depository (commonly known as Fort Knox) holds over half of the Treasury’s $428 billion gold reserves.
In this graphic, we put that amount into perspective by comparing Fort Knox’s reserves with central bank gold reserves worldwide. The data comes from the U.S. Mint and the World Gold Council. For illustrative purposes, we considered a pallet of 1,190 gold bars (400 troy ounces each) weighing approximately 14.8 tonnes.
What Is Fort Knox?
Located in Kentucky, Fort Knox is a U.S. Army installation that serves as the primary storage site for America’s gold reserves. The facility was established in the 1930s to protect gold from potential foreign attacks.
The first gold shipment arrived in 1937 via U.S. Mail from the Philadelphia Mint and the New York Assay Office. During World War II, Fort Knox safeguarded important U.S. documents, including the Declaration of Independence, the Constitution, and the Bill of Rights. It has also housed international treasures, such as the Magna Carta and the crown, sword, scepter, orb, and cape of St. Stephen, King of Hungary, before they were returned in 1978.
Currently, it holds 4,175 tonnes of gold, equivalent to nearly half of China’s gold reserves and four times the Swiss central bank’s reserves.
| Reserves | Gold (Tonnes) |
|---|---|
| 🇺🇸 U.S. Reserves | 8,133 |
| 🏛️ Fort Knox | 4,175 |
| 🇨🇳 China | 2,280 |
| 🇯🇵 Japan | 846 |
| 🇨🇭 Switzerland | 1,040 |
| 🇮🇳 India | 876 |
| 🇰🇷 South Korea | 104 |
| 🇸🇬 Singapore | 220 |
| 🇧🇷 Brazil | 130 |
| 🇲🇽 Mexico | 120 |
| 🇹🇭 Thailand | 235 |
Only small samples have been removed for purity testing during audits; no major transfers have occurred for years.
Gold Bar Specifications
- Size: 7 inches × 3 5/8 inches × 1 3/4 inches
- Weight: 400 ounces (27.5 pounds)
Extreme Security
Only a select few know the full security procedures, and no single person knows how to fully open the vault.
In 1974, a group of journalists and a Congressional delegation were allowed inside—marking the first official visit since Fort Knox’s creation. Previously, President Franklin D. Roosevelt was the only person other than authorized personnel to access the vaults.
In 2017, Treasury Secretary Steve Mnuchin, Kentucky Governor Matt Bevin, and several Congressional representatives became the second group to visit the vault.
Learn More on the Voronoi App 
If gold was shared equally, how much would you get? Check out this graphic to find out.
Real Assets
Charted: Top Suppliers of Aluminum and Steel to the U.S.
President Trump has imposed a 25% tariff on all steel and aluminum imports.
Charted: Top U.S. Suppliers of Aluminum and Steel
This was originally posted on our Voronoi app. Download the app for free on iOS or Android and discover incredible data-driven charts from a variety of trusted sources.
U.S. President Donald Trump has imposed a 25% tariff on all steel and aluminum imports, marking one of the most discussed measures of his first month back in the White House.
But which countries are most affected by these tariffs?
This map illustrates the top suppliers of aluminum and steel to the United States in 2024. The data comes from the U.S. Census Bureau. Aluminum includes unwrought aluminum, plates, sheets, and strips; bars, rods, and profiles; foil; wire; pipes and tubes; castings and forgings; and tube or pipe fittings.
Canada: The Largest Partner
Canada is by far the top supplier of both steel and aluminum to the United States. The neighboring country exported $9.4 billion worth of aluminum to the U.S. in 2024, significantly ahead of the second-largest exporter, the European Union, which exported $1.5 billion.
Canada also exported $7.1 billion worth of steel last year, compared to $7 billion from the European Union.
| Country | Steel Imports (USD) | Aluminum Imports (USD) |
|---|---|---|
| 🇨🇦 Canada | $7.1B | $9.4B |
| 🇲🇽 Mexico | $3.5B | $397M |
| 🇧🇷 Brazil | $3.0B | - |
| 🇨🇳 China | $799M | $809M |
| 🇹🇼 Taiwan | $1.3B | - |
| 🇰🇷 South Korea | $2.9B | $781M |
| 🇩🇪 Germany | $1.9B | $318M |
| 🇯🇵 Japan | $1.7B | - |
| 🇮🇳 India | $489M | $445M |
| 🇪🇺 European Union | $7B | $1.5B |
| 🇦🇪 UAE | - | $917M |
| 🇧🇭 Bahrain | - | $535M |
| 🇦🇷 Argentina | - | $468M |
| 🇹🇭 Thailand | - | $271M |
| 🇬🇧 UK | $440M | - |
Mexico, South Korea, and Brazil are also among the top suppliers of steel to the United States. Meanwhile, the country imports aluminum from other key partners, including China, the United Arab Emirates, South Korea, Bahrain, and Argentina.
A recent report by the Center for Strategic and International Studies (CSIS) noted that the U.S. produces less than 2% of the world’s primary aluminum.
Learn More on the Voronoi App
If you enjoyed this graphic, be sure to check out this chart illustrating the GDP impact of Trump’s tariffs on China.
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