What’s worth more than gold? 

Humans have mined the earth for metal and mineral resources for millennia. There is evidence of mining in southern Africa that dates back at least 45,000 years. 

In this month’s Learning Nugget, we dig into the topic of mining by exploring interesting and important mining sites across the world. 

The longest continuously-mined site

Before it closed in 1988, the Rammelsberg mine in Lower Saxony, Germany, had been the site of organized mining operations for 1,000 years (though some mining started there at least 3,000 years ago). This distinguished it as the place with the longest-known continuous mining history in the world.  

The mine produced copper, silver, lead, tin, and zinc and turned the nearby city of Goslar into an extremely wealthy place that was a seat of power throughout the Middle Ages.  

As the mines ran deeper and deeper into the earth, innovations were needed to make work and transport of extracted ores possible. This included ingenious water management systems created by monks that drained water out of mine shafts and ran it over wheels that generated power for a wide variety of mining tasks. 

Rammelsberg, Goslar, and the water systems in the area are all now recognized by UNESCO World Heritage. You can visit the mine and learn more about its history, significance, and the lives of the people who worked it. 

The largest rare earths mine

Rare earth elements have properties that make them absolutely essential in modern technology like cell phones, electric car batteries, energy efficient light bulbs, and more. China provides around 70% of rare earths currently on the market. Most of its supply comes from the Bayan Obo mine in the Inner Mongolian region of the country. 

Bayan Obo is by far the largest rare earths mine in the world, with some estimates saying over half of the world’s rare earths supply is mined there. 

„Rare earths“ is a term for 17 metals that don’t tend to occur in large concentrations in a single place in the way familiar metals like iron or gold do. Instead, they’re scattered in small quantities over large areas. This is the reason they’re „rare.“ It’s not because the earth has tiny reserves of them but because companies have a hard time mining them efficiently and profitably. 

China’s dominance in the rare earths market worries Western countries, especially given China’s friendly relationship with an ever more aggressive Russia. Western leaders are seeking ways to undercut China in the market by raising tariffs on Chinese rare earths and promoting domestic (or at least Western) mining efforts. 

The biggest producer of the
world’s most expensive metal

If you had to guess what the world’s most valuable metal was, you’d probably not think of the right answer: the little-known rhodium. For comparison, gold was recently selling for around €70 per gram whereas rhodium was worth over double that: nearly €150 per gram. 

Rhodium is very resistant to corrosion and is often used to coat jewelry made with other metals to protect it from wear.

But rhodium is most widely used in the automotive industry as part of catalytic converters, which help make exhaust fumes less toxic.

Rhodium has the ability to break down harmful nitrogen oxides that gas engines produce into the harmless single elements of nitrogen and oxygen, which helps cars meet emissions standards. 

A big reason rhodium is valuable is that it can’t be mined directly. It’s only produced as a byproduct when processing other ores, mainly platinum and nickel. The biggest producer of rhodium – and, unsurprisingly, of platinum – is South Africa. It generates around 80% of the metal on the market.

Rhodium may not be #1 for too much longer, though. As more drivers buy electric cars that don’t emit toxic fumes, rhodium won’t be needed in automotive production anymore.