The Environmental Impact of Mining (Different Mining Methods Compared)

Mining remains an essential and growing part of the modern industry. By some estimates, it makes up nearly 45% of the total global economy, and mineral production continues to increase as demand for raw materials grows around the world.

However, many mining techniques still in use can have serious impacts on both the mining site itself and the surrounding environment.

Here are some general effects of mining on the environment, the impact of different mining methods, and ways in which the industry is trying to make itself more eco-friendly.

The Environmental Impact of Mining

Here’s a quick outline of the various environmental effects of mining, and why mining is bad for the environment.

Air Pollution

Ore dust and gases released by the mining process are bad for the health of miners as well as the environment. Over time, exposure to the dust created by mining operations can lead to disease and buildup of scar tissue in the lungs.

Diesel-powered equipment, which naturally creates carbon emissions, further contributes to air pollution produced by mining.

Water Pollution

Materials left over by the mining process can easily make their way into local water systems, leading to increased acidity and heavy metal contamination that can destroy wildlife and render water undrinkable.

Some forms of mining also require the draining of underground water reservoirs called aquifers, which can cause serious impacts — like drying up springs, cutting off rivers and degrading local ecosystems.

Soil Erosion

Pit mining, one of the most common techniques, hollows out land to extract raw materials. It blasts away land and strips vegetation, leaving the area vulnerable to soil erosion — the wearing away of the topsoil layer of time. Topsoil is necessary for plants to grow, and without it, mining sites can’t truly recover.

Worse, soil erosion can often spread, meaning that mining can lead to effects on the soil beyond the site.

Habitat Damage

All these different effects add up to serious on-site habitat damage. Mining also creates knock-on effects — like water pollution, air pollution and vegetation loss as a result of soil eruption. This can lead to greater habitat loss beyond the immediate location.

Habitats can be restored after mining operations are finished, but some impacts will linger. Even in sites that are rehabilitated, biodiversity will typically be lower than it was before.

Different Mining Methods and their Environmental Impact

Different methods of mining have a variety of environmental impacts, ranging from minor to major.

Open-Pit Mining

Open-pit mining, one of the most common forms, is one of the most damaging. Miners hollow out a section of land, digging down to create a workable area and extract valuable raw materials.

This method leaves behind large pits in the earth and can contaminate the groundwater with chemicals used in the mining process. 

The land left behind, if not rehabilitated, is typically vulnerable to further soil erosion, further scattering what little topsoil was left over. It’s often not suitable for plant or animal life. Without human intervention, it may take years or decades for the land to become usable again.

Underground Mining

Underground mining, where miners tunnel beneath the Earth’s surface to extract mineral deposits, is rarer than open-pit mining. In 2014, it made up about 5% of all American mining operations — and has less of an impact on the surface.

However, this doesn’t mean that underground mining doesn’t have an effect on the environment. In fact, its environmental impact is quite large.

With this mining method, rocks and minerals are brought to the surface from tunnels underground. There, toxic chemicals in the waste material can escape into the environment and local waterways if not properly disposed of.

Underground mines can also cause subsidence on the surface — the land above begins to sink, usually when underground supports fail in abandoned or inactive mines. This can shift buildings, destroy infrastructure and harm the surface environment.

Underground mining can also sometimes lower the water table. If miners need to dig through an aquifer or water-laden layer of earth, water will need to be pumped out of the mine for work to continue. This dewatering can dry up springs, cut off rivers and degrade local ecosystems.

Some studies even suggest that while underground mining typically has less of a surface impact than the open-pit variety, it may have a worse effect on the environment overall.

Other Mining Methods

Some mining techniques — like in-situ leaching, which uses acid and water to remove minerals from a site without significantly disturbing the surface — have much less environmental impact. In-situ mining techniques can use less water than open-pit mining and underground mining, and also reduce the risk of releasing ore dust into the atmosphere.

However, even low-impact mining techniques like in-situ mining aren’t consequence-free. The strong acids used to break down ore and rocks can result in acidification of the surrounding environment. The acids can also dissolve the metal and radioactive isotopes in these ores during the leaching process, both of which can find their way into nearby water sources.

The Lasting Impacts of Mining

Part of what makes the environmental impact of mining so severe is how long their side-effects can last after the initial mining operations have ended.

For example, disturbed soil will often continue to erode away for a long time into the future, especially if leftover waste or a scattered topsoil layer prevents new vegetation from growing.

Ore residue and acid leach heaps left by mining processes can also erode rock and eventually pollute waterways. At the Holden Mine Superfund Site, for example, more than 100 million metric tons of leftover materials are currently at risk of leaching into the Columbia River. 

The company that owns the mine invested in a remediation wall to prevent these toxic waste materials from leaching into the river, but the wall isn’t a permanent solution. Severe flooding could easily wash the waste elements into waterways, meaning the site will likely require further rehabilitation.

Plastic and rubber left by equipment like earth-mover tires will stick around if not directly addressed. This can pose other problems, too — like the air pollution created as a result of diesel-burning engines.

These negative environmental effects can continue long after a mining company has stopped operations, packed up its equipment and moved on.

What’s more, even though rehabilitation can prevent the effects of mining from getting worse over time, not all companies invest in rehabilitating their sites. As a result, many are left alone to pollute the nearby environment for years or even decades to come.

Possible Green Future of Mining

Companies may move in the direction of sustainability — especially as pressure from individuals and governments push them to comply with higher standards of environmental and social governance (ESG). Expert leaders on ESG and industry professionals from within mining predict operations will begin to think more seriously about sustainability.

For example, some mining companies are experimenting with advanced land rehabilitation schemes that can help reintroduce plant life to former sites. 

With the use of biosolids — nutrient-rich organics derived from sewage treatment processes that are often used as soil conditioners in agriculture — it may be possible to reintroduce plant life to former mining sites in as few as 12 weeks.

Other, even more ambitious rehabilitation plans are focused on the best possible stewardship of former mining sites. These plans look to not only rehabilitate the land, but also aim to reintroduce 100% of the species that were living there before operations began.

Equipment upgrades could also reduce the impact mining has on the environment.

Machines with electric engines are becoming increasingly popular, with some companies, like Swedish mining equipment manufacturer Epiroc, even going so far as to pledge using 100% electric products over the next few years. Widespread adoption of electric engines could easily help the industry reduce the amount of carbon dioxide it naturally produces.

Low-impact mining techniques are also becoming more popular. In-situ mining is seeing bigger use in countries like China, which is trying to grapple with growing mineral demand, the size of the mining industry and the significant impact on the environment. 

Social changes from outside the industry may also naturally reduce mining’s carbon footprint over time and encourage more environmentally friendly techniques. For example, as businesses turn away from nonrenewable resources, mining may naturally follow suit.

Conclusion

Mining continues to be a huge component of the global economy — and in the future, it’s likely to only grow larger as the demand for raw materials increases.

This is troubling for those who care about the environment. Mining can often be devastating — causing water acidification, soil erosion and the degradation of local ecosystems. While some methods have less impact than others, it almost always has a serious and lasting environmental impact.

Fortunately, there is some hope that mining will become more sustainable in the future. The adoption of low-impact techniques and more eco-friendly equipment — plus pressure from environmentally minded individuals and governments — may make the industry more eco-friendly over time.

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About the Author: Jenna Tsui

Jenna is a tech journalist who co-owns The Byte Beat and frequently writes about the latest news in technology, disruptive tech, and environmental science and more. Check out her work on TBB or follow her on Twitter @jenna_tsui!