How do we mine a sustainable future?
Society is reliant on minerals and metals, yet we don't have enough to meet the world's demands. How do we meet this demand sustainably?
Mining a sustainable future?
Living sustainably has never been more important. We know that we need to decrease our emissions - this could be done by switching to renewable energies from non-renewable sources or by buying electric vehicles instead of petrol or diesel cars for example. In fact, governments around the world have signed into action a number of policies that target these factors (e.g. the UK government ban on the sale of petrol and diesel cars after 2030, and the Irish government target of 1 million electric vehicles on the road by 2030). But, have you ever stopped to think about how these technologies are made, and, more importantly, what they're made from?
New, green technologies are reliant on metals and minerals. The problem is, the increased demand for these technologies is putting pressure on our existing stocks of metals and minerals - there simply aren't enough to produce the amount of green technologies we need. We need to get our hands on more minerals and metals. So, how do we mine a sustainable future?
The incredible diversity of metals and minerals on our planet
If we think of a rock as a sentence, minerals are the words that make up that sentence, and elements, including metals, would be the letters that make up the words. Without metals and minerals, our Earth couldn’t exist.
The incredible diversity of minerals on Earth. These stunning minerals all host metals that we are reliant on for our sustainable future. From left to right, the images are: Top row - Assurite (Copper), Kunzite variety of Spodumene (Lithium), Hiddenite variety of Spodumene (Lithium). Second row - Gersdorffite (Nickel), Cassiterite (Tin), Native Copper. Third row - Cobaltite (Cobalt), Erythrite (Cobalt). Fourth row - Lepidolite (Lithium), Platinum nugget. All images © The Trustees of the Natural History Museum, London.
Our planet is host to a huge number of important minerals and metals. These metals and minerals are incredibly important to us – look around you, what do you see? Your phone, your computer screen, a table, a chair? Ask yourself, what are these things made of? There is a saying in geoscience: if it’s not grown, it’s mined. Everything that you can see that wasn’t grown probably came from a mineral or metal that was mined before it was turned into the thing you’re looking at.
We know that our society needs to become more sustainable. We need to switch to electric cars, to transition to renewable energies and to recycle everything that we produce. The trouble with this is that the new, sustainable technologies all require metals to build, and these metals must come from somewhere. Our goal is to build a truly circular economy but recycling alone is unable to supply the metals we urgently need today, and so new metals must be mined.
We must mine our own sustainable future. Keep interacting to find out how.
Exploration
Before we can use any metal, we need to find it. How do geoscientists do this? Let’s use the example of Lithium.
Lithium metal - image by Dnn87 and reproduced using a CC 3.0 license
Lithium is vital for the batteries that power everything from our phones and laptops to electric vehicles. Currently, Europe’s supply of this crucial metals comes from places such as Chile, China and Australia. Transporting anything from these locations takes time and is very carbon intensive. Providing a more local supply of lithium is crucial to reducing the carbon footprint lithium has before it even becomes a battery.
Cornwall in the UK has the potential to produce sustainable lithium. Lithium can be found in the rocks and groundwater of Cornwall.
Cornish Lithium is an eco-technology company that seeks to provide the raw materials for the Green Industrial Revolution. In this video, they show how they go about finding lithium and extracting it safely and sustainably from the rocks in Cornwall.
Video by Cornish Lithium
Exploration isn’t limited to the minerals and metals that we already know about! Did you know that we’re still finding new minerals today? These new minerals can be really useful for finding new sources of minerals and metals, like lithium, that we need for our sustainable future. Mike Rumsey, Principal Curator at the Natural History Museum explains how his team went about discovering Jadarite, a new lithium mineral from Serbia.
Understanding and testing for minerals
Before we take rocks out of the ground, we need to work out exactly what’s in them. Minerals occur within rocks and they occur in varying amounts. We need to test the rocks to make sure they contain lots of the mineral that we need in comparison to the background rock. We don’t want to extract any more rock than we need, so making sure the rock we do extract is full of the mineral we need is really important.
To put this in perspective, we need to extract 0.7 kg of rock for to make the battery in one mobile phone. To produce enough metal for the 80 million mobile phones in the UK, you would need 56000 tonnes of rock, or the equivalent weight of 9000 elephants! If the rocks we extracted weren’t full of the minerals that we need, we’d have to extract even more rock on top of this!
Scientists can work out what minerals are in a rock both out in the field and in the laboratory.
Understanding the chemistry of rocks - geochemistry
Scientists want to understand the chemistry of rocks for a variety of reasons, from understanding how the earth was made, to understanding how it has changed through time. Geochemical study of rocks tells us the chemical makeup of rocks, which is useful for finding out what minerals and metals it might contain, and if they're present in large enough quantities to be sustainably extracted.
To find out the chemical makeup of a rock, it must first be broken down. Join Dr Emma Humphreys-Williams to find out how!
Using X-Rays to Understand Rocks
Rocks, and the minerals that make them up, are crystalline - they are made up of crystals. Understanding what crystals are present in a rock helps us to understand the minerals that are inside. One of the ways we can understand this is through the use of X-Ray Diffraction. Dr Jens Najorka explains what this technique is and how it is used to better understand what is inside rocks.
Rocks under the microscope
The last two videos used the chemical and physical properties of rocks to identify the minerals that make them up. Often, the first port of call for identifying rocks is by looking at them under the microscope. Minerals under the microscope often have their own unique optical properties, looking carefully can help to identify which minerals are hidden inside the rocks you're interested in. In this video, Dr Simon Kocher explains how we look at rocks under a reflected light microscope.
Rocks under the Scanning Electron Microscope
Sometimes a more powerful microscope is needed to identify the minerals inside a rock. Using a scanning electron microscope allows scientists to see the minerals and elements that make up rocks down to a nanometer scale. Join Dr Will Brownscombe to find out how the scanning electron microscope, or SEM for short, works and how scientists use it.
Mining
We’ve learned about how we explore for minerals, but how do we actually get them out of the ground? Use our interactive tool to find out!
User Dashboard - Infogram
How do we get minerals out of rock?
Let’s use the example of Lithium again. Remember how you need 0.7 kg of rock to produce the metals for one phone battery? Well, how do we separate the metal we want out of the rock we don’t want?
Our first step is to grind the ore (the rock that contains the lithium we want, along with general rock we don’t want) to a tiny particle size – 200 nanometers. When the ore has been milled to this fine powder, we can add it to water. We can then use a variety of techniques to separate the metal we want from the waste we don't want.
Froth Flotation
Now we have a rock powder and water, so what’s next! To separate out the lithium we want, we need to make it hydrophilic, that is, making the lithium able to stick to the water particles. We do this by adding a few chemicals into the mixture.
So what do we do at this point? Out lithium is stuck to the water particles, but we’ve still got bits of rock and other chemicals in there that we don’t want. How do we separate the lithium out from the rest of this?
The answer is: Froth Flotation
What we can now do is pump air through the mixture that we have. This causes bubbles to form and the hydrophilic lithium will stick to these bubbles. By scraping off the bubbles, we can collect a concentrated lithium mixture and leave the rest of the rock behind.
Gravity Separation
Froth flotation isn’t the only way of getting our metals out of the rocks we want. Let’s have a look at Gravity Separation.
Here particle density is the key. Density defines how compact an object is; it is the mass of an object divided by its volume.
In a spiral sluice, the more dense material is pulled to the inside of the spiral, whereas the less dense material is forced to the outside. This allows for the separation of economic material (more dense) from waste (less dense) as is shown in the video.
Gravity Separation via Shaking Table
On a “shaking table” more dense particles are getting caught behind the table riffles (the ridges you can see) and the less dense particles are flowing over the top. The shaking action of the table moves the dense particles along the top of the table, where they are collected as a concentrate, whereas the less dense gangue is collected as tailings.
Magnetic Separation
As the title suggests, magnetic separation uses magnets to separate the magnetic material that we do want from the non-magnetic material that we don't want.
Harnessing Natural Phenomena
Are there less energy intensive alternatives to getting minerals out of rock? Would you believe that scientists are developing new methods of separating metals from rock by using bacteria!
Cobalt is one of the most important metals for our sustainable future, but getting our hands on it can be really tricky. The team at the University of Bangor are developing a way of using bacteria to sustainably take cobalt out of rock. Watch our video to find out more!
Dr Ana Santos from Bangor University explains how she and the team at Bangor work with metal munching bacteria!
Reducing Environmental Impact
In an ideal world, we wouldn’t mine at all. We would get all the minerals and metals that we need from recycling the things that we already have. This is called the ‘Circular Economy’.
The Ideal Circular Economy
At the moment, we don’t have technology that is advanced enough to recycle every single thing and waste is still created. There are still inputs and outputs to the system, but recycling is happening!
Our current economy - not quite circular yet
We can all play our part in contributing to the circular economy by recycling our technology. How many dead mobile phones or laptops do you have at home? There's so much metal lying around in unused or dead technology in people's homes that this is sometimes referred to as 'The Urban Mine'. Consider recycling your old tech – the more we recycle, the less we have to mine.
Mine Rehabilitation
So far we've learned that minerals and metals are crucial to our sustainable future, and we've learned how to explore for them, mine them and get the minerals and metals we want out of their host rock. Let's take a step back and think about mines again, what happens when the mineral that we want to extract runs out?
Did you know that a plan for mine closure has to be submitted by a mining company before permission is granted for the mining to happen? This ensures that, when the mineral that we wanted to extract runs out, the mine is closed sensitively and sustainably.
Some of the best examples of sustainable mine rehabilitation have come from the UK and Ireland. For example, would you believe that the Eden Project in Cornwall is situated on an old China Clay mine? In Ireland, Lisheen Quarry is now the Irish Centre for Bioeconomy and forms the Irish Bioeconomy Campus.
Before and after: Lisheen mine just before closure in 2012 and post closure. Images used with the kind permission of Vedanta.
How do we mine a sustainable future?
Green technologies, such as renewable energy infrastructure and electric vehicles are reliant on minerals and metals. As we move forward into a sustainable future, we've learned how our dependence on mined material is increasing to meet the demands for minerals and metals these green technologies create. Mining is necessary to meet these demands, and is ultimately at the root of providing enough green technology to enable our society to have a sustainable future.
In the future, we hope to have a truly circular economy. By mining enough of the minerals and metals that we are reliant on for green technologies now, we hope to create a supply that will be continuously recycled into new technologies moving forward, and our reliance on mining will decrease. One day, we may not need to mine at all.
For now though, our research into minerals, metals and mining will continue to keep finding new, groundbreaking and environmentally conscious ways to find, extract, process and refine the minerals and metals we need to create a sustainable future for our society.
