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.

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.

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.

Visualizing the $2.9B Money Flow into Gold Exploration

In 2020, the price of gold reached multi-year highs, in part to the impact of COVID-19 shutdowns. This renewed interest in gold spurred the plans of many gold exploration and development projects around the world.

This infographic uses data from Mining Intelligence which tracked the $2.87 billion from 425 transactions for gold projects in 41 countries between February 1, 2020, and February 28, 2021.

Gold Financings, by Country

Five countries accounted for 75% of the money raised for top gold projects around the world.

Canada attracted the most with $965 million or roughly 34% of all the money raised for gold exploration and development.

In second place, Mexico attracted $389 million or 14% of total exploration dollars raised while Australia with $291 million (10%) is in third place.

The United States comes in fourth place with $256 million or 9% of global gold exploration dollars. Chile on the fifth spot received $254 million (9%) with one project attracting the largest amount of any on the list.

Top 10 Financings by Gold Project

Focusing on individual projects, Gold Fields’ Salares Norte project in Chile received $252 million for the largest financing of the period. The company started construction this year, after a delicate operation to remove endangered chinchillas from the site.

Silvercrest’s Las Chispas project in Mexico’s Sonora state received $228.9 million, giving it the second largest sum. According to the company, the property hosts 94.7 million ounces of silver equivalent (AgEq) in proven and provable reserves.

Gold is Canada’s most valuable mined mineral and the next 3 projects on the list show this priority. Osisko Mining’s Windfall Lake project in Quebec is third ($130 million), Artemis Gold’s Blackwater mine ($130 million) in British Columbia is the fourth, and Argonaut’s Magino project in Ontario ($108 million) the fifth.

The analysis found that more than half of the money raised (57%), went to 63 gold projects to advance economic studies – from scoping studies or preliminary economic assessments through to bankable feasibility studies and permitting.

A total of 71% of the projects were in the early stages of exploration, but they only accounted for about 25% of the total capital raised during the period.

Gold Going Forward

With $2.9 billion in capital going into gold projects around the world, the gold industry has big plans. These financings represent opportunities for host countries’ economies and their workers, along with more gold for investors to buy.