What Are the Environmental Impacts of the Mining Industry?
Most of the luxuries of modern society – including phones, multi-story buildings, tools, jewelry, and electric vehicles – wouldn’t be possible without mines. As the demand for clean energy continues to grow, so, too, does our reliance on mining for sourcing critical metals and minerals. Unfortunately, the mining industry is a historically dirty business.
From air and water pollution to land degradation, mining has a lasting impact on the surrounding environment – not to mention communities. Given that demand for the products of mining continues to increase, it’s clear that governments and companies must turn towards more environmentally friendly mining practices and technology.
As with other issues topical to the environmental movement, mining is a complicated, convoluted beast. While the focus of this article is the environmental impacts of mining, it’s impossible not to also touch on its significance, social impacts, and future. With that said, let’s dig in!
Photo by Albert Hyseni
The contribution of mining to society
In order to get a complete picture of the environmental impact of mining, it’s important to understand what mining has done for our society throughout history, both good and bad. For that, a very brief history of mining is in order:
Over 2 million years ago, Homo Sapiens started making stone tools by searching for the best available rocks. These early mining efforts would evolve over the course of thousands of years; stone would eventually be complemented by other materials such as obsidian, coal, and clay, all of which could be crafted into useful objects, tools, and weapons. It is believed that increasingly complex tools go hand in hand with the cognitive and cultural evolution of humankind.
The oldest known underground mine is Ngwenya Mine in Swaziland, with evidence suggesting that ores were extracted at least 40,000 years ago for red ochre, and later for iron ore. Red ochre was an important element of cultural ceremonies, while metals such as iron were used to make more advanced tools and weapons, especially once it was discovered that fire could extract metal from ore.
The discovery of smelting revolutionized human civilization. Metals could be turned into currency, weapons, tools, and building materials. Meanwhile, minerals such as coal and salt became essential for heating, cooking, and food preservation.
As civilizations developed, so did their reliance on mining. This in turn fueled expansion, trade, and exploration, as characterized by the Age of Exploration: a thirst for precious minerals and gemstones such as gold drove countries to fund exploration, resulting in massive quantities of spoils and discoveries but leaving behind a trail of bloodshed.
Of course, one can’t talk about the history of mining without also mentioning the Industrial Revolution; the two are inextricably intertwined. Technological advancements (such as the steam engine) revolutionized mining operations, which were simultaneously responsible for fueling the advancements in the first place. The mining industry subsequently boomed, but it was manned largely by poor laborers who suffered disastrous hazards and health consequences.
Today, mining is no less essential to modern life than it was 100 years ago; everything from asphalt to petroleum is a product of mining. Continuing advancements in technology have increased the rate and capacity of mining while simultaneously reducing its reliance on brute manpower, but mining continues to be a hazardous occupation that affects not only its workers but also the surrounding environment and communities.
An overview of different types of mining
Most people have never set foot in a mine. And without that experience, it can be tough to know what mining actually looks like. In films, mines are often portrayed as dingy, underground mines with heavy wooden beams, flickering lights, and a maze of tunnels. While that image may have been accurate at one point in history, modern mines are very different beasts.
Today, there are four main categories of mining:
Surface mining: method for extracting materials close to the surface, such as coal, iron, and bauxite. Because it often involves blasting large areas of land, surface mining is particularly destructive to the surrounding landscape. Types of surface mines include strip mines, open-pit mines, and mountaintop removal mines.
Underground mining: extraction of materials found deeper below the surface, including gold, lead, and silver. This type of mining is typically more dangerous and more expensive than surface mining. Types of underground mines include room and pillar mines, block caving mines, and longwall mines.
Placer mining: like surface mining, placer mining happens primarily above ground. Instead of extracting materials through blasting, however, valuable materials are recovered from sediment through sifting. This type of mining usually happens along riverbeds or in environments with natural sediment accumulation.
In-situ leach (ISL) mining: less well-known, in-situ mining is a method of recovering minerals without extracting rocks and ore. Instead, the desired minerals are dissolved by solution injected into the ore deposit and are then pumped back out to the surface where they can be recovered. This method results in relatively little surface disturbance, but can cause significant pollution to groundwater. In-situ leach mining is most often used to extract uranium.
The above categories are helpful for getting an overview of mining, but to really understand the mining process from start to finish it’s important to know that the process doesn’t end after extraction. In fact, the processing of ore that takes place once it’s extracted from the earth through mining is complex and environmentally-taxing in its own way. As with mining itself, metal extraction is complicated, and looks different depending on the type of mineral or metal being targeted. But there are more or less 4 stages of ore processing:
Crushing and grinding: this step reduces the particle size of rocks for the next steps of processing.
Sizing and classification: different sizes of ore are separated through screening.
Concentration: materials are broken down and separated through one of various ways: automated sorting, electrostatic separation, froth flotation, gravity separation, or magnetic separation.
Dewatering: in the final step, water is removed to reach the desired mineral concentrate.
At this point, the extracted ore is still considered to be crude and requires even more processing! But in this form, it can more easily be transported to the next processing facility, where ore is smelted or refined into the desired metal. Only then can the metal be used to make the products that we’re familiar with.
The environmental impacts of mining
Now that you have a better idea of what the mining process involves, it’s slightly easier to grasp the scale of its environmental impacts. While the different types of mining (underground, in-situ leaching, etc.) impact their surrounding environments differently, the effects are often overlapping. Therefore, in order to avoid further complicating things, we’ll go over the environmental impacts of mining as a whole rather than on the basis of individual mines.
Air pollution
Globally, the mining industry is estimated to account for approximately 4-7% of all GHG emissions. However, it’s likely that this estimate is on the low end – some estimate that the manufacturing of iron and steel alone accounts for more than 7% of global GHG emissions.
The majority of GHG emissions in mining are a result of energy usage, as mining processes and transportation are incredibly energy-intensive. However, it’s also to keep in mind that there are “extra” emissions from land degradation: mining involves some amount of deforestation (especially with open-pit mines), which results in emissions as stored carbon dioxide is released back into the atmosphere.
In addition to greenhouse gasses polluting the air, mining results in significant amounts of ore dust, road dust, and other toxic air pollutants, all of which can affect the health of miners and surrounding communities for long periods of time.
Water pollution
Besides energy, mining requires immense amounts of water throughout the entire process, from extraction to processing. As the water mixes with metals, toxic waste, and dust, it becomes contaminated. While modern mines have water treatment systems and take precautions to reduce groundwater pollution, it’s still a significant concern. Communities living near mines often suffer from water stress due to a combination of high water usage and groundwater pollution.
Even though in-situ leach (ISL) mining causes relatively little surface disturbance, it results in large amounts of water pollution, due to the chemical-water solution that’s injected into ore deposits. Additionally, ore processing uses large amounts of water to sort and refine metals. The resulting water is contaminated and needs significant water treatment before it can be considered non-hazardous. Unfortunately, toxic wastewater from mining sites is often dumped into nearby streams and water sources.
Finally, mining results in water pollution in another significant way: mining exposes sulfides in the soil, which, when mixed with rainwater or streams, form acids. The resulting acid water damages plants and animals and is dangerous to the health of people if it ends up in the groundwater.
Land degradation
Finally, no matter the type of site, mining results in significant land degradation and subsequent biodiversity loss. Surface mining, such as open-pit mining, is particularly destructive as it typically involves blasting large areas of land, which strips vegetation and leaves the topsoil vulnerable to erosion.
However, all types of mining affect the land; even underground mines require stripping large swaths of land to develop the surrounding area – such as building mining infrastructure, roads/railways, and mining communities or encampments. This is especially noticeable in remote areas, as accessing more remote mines often means significant ecological impact and deforestation.
All of this adds up to impact not only the soil, but also wildlife and plants – often affecting habitat beyond the immediate mining site. As with landfills, however, mines are eventually exhausted, at which point they can be closed and reclaimed to restore it to an ecologically useful landscape.
The social impacts of mining
It’s difficult to talk about environmental issues without also talking about social issues; the two go hand-in-hand. Mining is no different.
Historically, mines have been worked by slaves, indentured servants, children, and poor laborers. The unsafe conditions and toxic pollutants not only result in frequent (and potentially fatal) accidents, but health effects can be severe and long-lasting (e.g., black lung disease, a result of inhaling coal dust).
Today, U.S. miners are paid a relatively good wage, but the conditions are still considered highly unsafe, and accidents happen regularly. Plus, the environmental effects of mining, including air pollution and water pollution, often disproportionately affect low-income communities.
Unfortunately, in developing countries things look even worse. Child labor in mining continues to be a rampant issue, and conditions are often vastly more unsafe due to lack of proper infrastructure and technology.
Moving towards greener mining practices
Over the last decade, mining has received a lot of criticism from the environmental movement, and for good reason. But it would be hypocritical to discuss the negative impacts of mining without accepting that it’s a vital part of our society, one that we benefit from in many ways. In fact, demand for mining remains steady, and it won’t go away anytime soon so long as we continue to rely on vehicles, fossil fuels, batteries, cell-phones, and more.
But that doesn’t mean that mining can’t evolve to become more environmentally friendly. Pressure from environmentalists, governments, and the private sector can drive change in the mining industry for the better.
From improving land rehabilitation after a mine closes to electrifying mining vehicles, there are many ways to reduce the environmental effects of mining. For example, researchers have identified possible ways to make water usage in mining more efficient, especially in already arid environments. Additionally, improving recycling rates of various metals (especially valuable minerals used in EV battery production) can help reduce our reliance on the extraction of virgin materials.
What other questions do you have about the environmental impacts of the mining industry? Let us know in the comments below!
