Unearthing the Essence: Quantifying Earth’s Shifting Landscape for One Tonne of Copper

Digging Deep: What Does a Tonne of Copper Really Cost the Earth?

Copper. We take it for granted, right? It’s in the walls of our homes, the guts of our smartphones, and the engines of electric cars. It’s absolutely essential for modern life, especially as we push towards greener technologies. But have you ever stopped to think about what it really takes to get that copper out of the ground? I mean, beyond just the price tag at the hardware store? Turns out, it’s a heck of a lot more than you might imagine.

One of the biggest challenges facing the copper industry today is something called “declining ore grades.” Basically, it means the good stuff – the copper-rich rock – is getting harder and harder to find. Back in 1990, the global average ore grade was around 1.6%. Nowadays? We’re scraping by with about 0.45%. Think about that for a second. That’s a massive drop! And in the US? A century ago, miners were pulling copper from ore that was about 2% pure. Now, it’s closer to 0.4%. It’s like trying to find gold flakes in a sandbox – you need to sift through a lot of sand. As one expert, Richard Schodde, put it, the next generation of mines are likely to have even lower grades than we’re seeing today. Yikes.

So, what does this mean in practice? Well, for starters, it means bigger mines. To get the same amount of copper, companies have to dig up and process way more rock. And that, my friends, has some serious consequences. We’re talking about larger operations, more environmental destruction, and a whole lot more energy being used. It’s a domino effect, really.

And speaking of destruction, let’s talk about land. Open-pit mining, which is how most copper is extracted, is basically like carving a giant hole in the Earth. I’m talking holes that can be nearly a mile wide and thousands of feet deep! To get to the copper, you have to bulldoze forests, strip away topsoil – the stuff that plants need to grow – and completely reshape the landscape. It’s not pretty, and it definitely has a lasting impact. The sloping nature of open-pit mines also accelerates soil erosion.

But wait, there’s more! All that extra rock that’s dug up has to go somewhere. And that “somewhere” is usually in the form of massive waste piles. For every single tonne of copper we pull out of the ground, we leave behind about 99 tonnes of waste. Let that sink in. A typical large copper mine might process 270,000 tonnes of mined material every single day to get just 1,750 tonnes of copper concentrate. That waste includes everything from waste rock and overburden to tailings (the leftover gunk after the copper is extracted) and heap leach wastes. And guess what? This waste often contains nasty stuff like radionuclides, which can lead to acid mine drainage (AMD) when exposed to air and water. AMD is basically toxic runoff that pollutes water sources with heavy metals and sulfuric acid, killing aquatic life and making the water unsafe for humans. In fact, copper mining wastes make up the largest percentage of metal mining and processing wastes generated in the United States.

Then there’s the water issue. Copper mining is thirsty work. Back in the 50s, the US copper industry was guzzling about 330 million gallons of water per day. While the exact amount varies depending on the location and the technology used, it can take over 100,000 gallons of water to produce just one tonne of copper. That’s enough water to fill a small swimming pool! And a lot of that water ends up getting contaminated. You might see the water around a copper mine turn reddish because of copper acid. This contaminated water can seep into groundwater, poisoning aquifers, killing fish and wildlife, and making farmland unusable.

Finally, let’s not forget about energy. The copper industry is a major energy hog, which means it’s also a significant contributor to greenhouse gas emissions. The theoretical minimum energy required for primary copper production from sulfide ore is between 1.4 to 2.2 GJ per tonne of metal. However, the actual specific energy consumption (SEC) for ore from an open-pit mine with a 1.32% ore grade ranges from 25 to 30 GJ per tonne of metal. To put things in perspective, the world produces around 21 million tonnes of copper annually, which contributes about 0.2% to 0.3% of global GHG emissions. In 2018, the average GHG emission intensity of refined copper production was 4.6 tonnes of CO2e per tonne of copper . And here’s a kicker: copper is more than twice as carbon-intensive as steel!

Okay, so it sounds pretty bleak, right? But there’s hope! The good news is that there are things we can do to make copper mining more sustainable.

For example, recycling copper is a no-brainer. It requires 80%–90% less energy than mining new copper. In fact, about 40% of the copper we use today comes from recycled scrap. We can also invest in new technologies that use less energy and water. And we can switch to renewable energy sources to power our mines. Some mines are even starting to use dry stacking for tailings, which reduces the risk of water contamination.

The bottom line is this: copper is essential for our future, especially as we move towards a greener economy. But we can’t just keep digging it up without thinking about the consequences. We need to find ways to mine copper more responsibly, to reduce our environmental impact, and to make sure that we’re not sacrificing the health of our planet for the sake of progress. The road to a green economy is paved with copper, but we need to make sure that road is sustainable.