Mining can affect the environment in different ways, such as locally, regionally, and globally. This happens through both direct and indirect mining activities. Mining can cause erosion, sinkholes, loss of plant and animal life, and pollution of soil, groundwater, and surface water from chemicals used in mining. These activities also release carbon into the air, which contributes to climate change.
Some types of mining, such as lithium mining, phosphate mining, coal mining, mountaintop removal mining, and sand mining, can have serious effects on the environment and public health. Because of this, some countries require mining companies to follow strict rules to protect the environment and restore mined areas to their original condition. While mining can provide benefits to society, it can also cause conflicts, especially about how land is used both on the surface and underground.
Mining operations are demanding and disruptive, often harming local ecosystems and affecting Earth's overall environmental health. To build mines and related structures, large areas of land are cleared, using large amounts of energy and water. This process also releases air pollution and creates dangerous waste.
According to The World Counts, the amount of resources mined from Earth increased from 39.3 billion tons in 2002. This is a 55% increase in less than 20 years. This level of mining puts Earth's natural resources under heavy pressure. Currently, humans are extracting 75% more resources than Earth can naturally replace over time.
Erosion
Erosion of exposed hillsides, mine waste piles, and tailings dams can lead to sediment buildup in drainages, creeks, and rivers, which harms nearby areas. A well-known example is the large Ok Tedi Mine in Papua New Guinea. Soil erosion can reduce the amount of water available for plants to grow, which may cause a decrease in the number of plants in an ecosystem.
Soil erosion happens when mining activities, such as digging and blasting, disturb natural areas. These activities damage tree root systems, which are important for holding soil in place and preventing erosion. Eroded soil and rocks can be carried by rainwater into nearby water sources, creating sediment buildup. Changed water flow patterns from mining can also increase erosion and sediment buildup in rivers and streams. Over time, these effects lead to poor water quality, loss of animal and plant habitats, and lasting harm to the environment.
Sinkholes
A sinkhole near a mine is usually caused when the mine's roof collapses after resources are removed, when the layers of soil and rock above the mine are weak, or when there are cracks or weak spots in the ground. The layers of soil and rock above the mine can create empty spaces underground, which may fill with sand and soil from the layers above. These empty spaces can eventually collapse, forming a sinkhole on the surface. When the ground suddenly collapses, it creates a large hole that can be dangerous to people and buildings. To reduce the risk of sinkholes at a mine, structures like strong supports and walls can be built around areas that are likely to sink. Empty spaces in old underground mine areas can be filled with materials, and special liquids can be used to strengthen the ground.
Water pollution
Mining can harm nearby surface and groundwater. If steps are not taken to prevent it, very high amounts of harmful chemicals, such as arsenic, cyanide, sulfuric acid, and mercury, can spread into large areas of water. Water used for mine drainage, cooling, and other processes increases the chance of these chemicals polluting ground and surface water. Mining creates large amounts of wastewater, which is hard to dispose of because it contains harmful substances. Water runoff with these chemicals can damage nearby plants. Dumping this runoff into surface water or forests is the worst choice. Submarine tailings disposal, where waste is pumped to great depths, is considered a better option. Storing waste on land and refilling the mine after it is no longer used is even better if forests do not need to be cleared for storage. Chemical leaks from mining can pollute watersheds, which affects the health of people living nearby.
In well-managed mines, hydrologists and geologists carefully measure water to prevent contamination from mining activities. In the United States, federal and state laws require mining companies to follow standards that protect surface and groundwater from pollution. This is best done using non-toxic extraction methods, such as bioleaching. Protection from water contamination must also continue after a mine is closed, as water systems can still become polluted years later.
Air pollution
The mining industry adds about 4 to 7% of the world’s greenhouse gas emissions. These gases, such as carbon dioxide (CO₂) and methane (CH₄), are created both directly and indirectly during mining activities. These emissions can greatly affect the Earth’s climate.
Air pollutants harm plant growth by interfering with how plants collect resources. When leaves are exposed to the air, pollutants like ozone (O₃) and nitrogen oxides (NOx) can damage the leaves’ ability to produce food through photosynthesis. Pollutants that settle on soil, such as heavy metals, harm plant roots and reduce how well plants can take in water and nutrients. These changes reduce the plant’s ability to grow and can affect how resources are used by different parts of the plant. If air pollution happens at the same time as other stressors, like drought, the effects on plant growth depend on how the plant responds to multiple challenges. At the ecosystem level, air pollution can change which plant species compete best, altering the types of plants in an area. The effects of air pollution depend on the kind and amount of pollutant released. In farmland, this can lead to lower crop production.
To reduce air pollution from mining, methods often focus on using cleaner energy. Switching from coal and diesel to gasoline can lower greenhouse gas levels. Using renewable energy sources, like solar or hydroelectric power, can further reduce emissions. Improving mine efficiency and using life-cycle assessments to plan for environmental effects can also help reduce pollution.
Subsurface mining happens below the water table, so water must be pumped out to avoid flooding. When a mine is closed, pumping stops, and water fills the mine. This is the first step in acid rock drainage, a process that occurs naturally in some areas but is worsened by mining activities. Acid rock drainage can happen in places where rocks with sulfide minerals are disturbed, such as construction sites or transportation routes. In areas with coal waste, water can become highly acidic and is called acid mine drainage (AMD). Similar issues can occur in coastal areas where acid sulfate soils are disturbed.
Five main technologies help manage water flow at mines: diversion systems, containment ponds, groundwater pumping systems, subsurface drainage systems, and subsurface barriers. For AMD, polluted water is usually sent to a treatment facility to remove harmful substances. A 2006 review found that predictions about water quality after using pollution controls often underestimated the actual damage to groundwater, streams, and lakes.
Heavy metals are naturally occurring elements with high density and weight. They are not easily broken down and can stay in the environment for a long time. They can build up in living things, which is a concern for human and environmental health. Heavy metals are used in many industries, leading to their widespread presence in the environment.
Naturally occurring heavy metals are often in forms that plants cannot easily take in, such as in minerals or complex structures. They are strongly held in soil and are not easily available to living organisms. However, how heavy metals interact with soil and organisms depends on the soil’s properties and the types of organisms present. Naturally occurring heavy metals bind tightly to soil, more so than those from human activities.
When heavy metals are carried by runoff or groundwater, they cause environmental problems. For example, the Britannia Mine, a former copper mine near Vancouver, Canada, and Tar Creek, an abandoned mining area in Oklahoma, both face heavy metal contamination. At Tar Creek, heavy metals like lead and cadmium leaked into groundwater. High levels of heavy metals in water can change pH, how well water resists pH changes, and the amount of oxygen in water. Storing mining waste for long periods can cause problems, as dust and waste can be blown away by wind, as seen at Skouriotissa, an abandoned copper mine in Cyprus. Climate change and increased mining may raise heavy metal levels in river sediments. These effects are often worse in areas near the source of heavy metals.
Effect on biodiversity
Mining affects biodiversity in many ways across different areas. Locally, mining directly destroys habitats where plants and animals live. On a larger scale, mining causes problems like pollution and climate change, which affect regions and the whole world. To protect biodiversity, conservation efforts must address both the direct harm at mining sites and the long-term environmental effects. Setting up a mine changes the habitat, and smaller changes can spread over large areas. For example, waste from mines can pollute the environment for a long time. Even after a mine stops operating, harm to biodiversity can continue. Destroying or changing the original habitat is the main cause of biodiversity loss, but harmful effects from mining materials, such as direct poisoning or contamination of food and water, also harm animals, plants, and microorganisms. Changes to the environment, like pH and temperature, can disrupt nearby communities. Endangered species are especially vulnerable because they need very specific living conditions. Even small changes to their habitat can put them at risk of disappearing. Habitats can be damaged when there is not enough natural material, such as when large rocks from mines are left in the environment without considering their impact.
Heavy metal pollution from mines decreases as distance from the mine increases, and the effects on biodiversity follow a similar pattern. The impact depends on how easily the contaminant moves and how much of it is taken up by living things. For example, the form of metals in sediments can change how harmful they are to aquatic life.
Biomagnification is important in polluted areas: even if mining does not kill organisms directly, the effects are often worse for animals higher up the food chain.
The harm mining causes to biodiversity depends on the type of contaminant, how much is present, and the type of ecosystem. Some species can survive pollution, while others may disappear. Time alone is not enough for habitats to fully recover from mining damage. Remediation efforts take a long time, and in most cases, the original variety of life before mining cannot be restored.
Mining can harm aquatic life in several ways. Direct poisoning is more likely when contaminants are easily moved through sediments or water. Mine drainage can change water pH, making it hard to tell if harm comes from the chemical itself or from pH changes. Still, effects from pH changes can be clearly seen. Contaminants can also harm aquatic life physically, such as when high levels of sediment in streams block sunlight, reducing algae growth. Metal deposits can cover algae or their surfaces, preventing them from growing.
Conditions in areas with acid mine drainage change over time, such as temperature, rainfall, pH, salinity, and metal levels. These changes affect communities living there. For example, changes in pH or temperature can alter how much metal is dissolved and available to harm living things. Contamination can last for many years. For example, even 90 years after a pyrite mine closed, water remained very acidic, and only acid-loving bacteria survived.
A well-known example of mining harm is the contamination in Minamata Bay, Japan. Methylmercury from a chemical company was released into water, causing a disease called Minamata disease. This led to mercury poisoning in fish and shellfish, which harmed other animals and people who ate the contaminated seafood. Another example is phosphate mining near Christmas Island, which caused high phosphate levels in nearby coral reefs. This led to a decline in important reef-building species, like certain corals and algae, likely because the phosphate helped fast-growing algae outcompete them.
Algae communities in very acidic water with high zinc levels are less diverse, and mining pollution reduces their ability to produce food. Diatoms, a type of algae, are greatly affected by chemical changes, pH, and high metal levels. Some diatom species can survive in high-metal environments, but in very polluted areas, algae and plankton populations are much lower. Zooplankton, which are tiny animals, are also harmed by severe mining impacts. However, in some cases, the total amounts of phytoplankton and zooplankton may stay the same even if their types change.
When considering the risks of mining to marine life, it is important to look at other vulnerable communities, like those on the seafloor, which can be harmed by deep-sea mining. Microbial life is essential for ecosystems on the seafloor and supports important chemical processes. Deep-sea mining often targets areas like hydrothermal vents, where valuable minerals are found. Other mining areas include inactive vents, manganese-rich formations, and cobalt crusts on seamounts. These areas have extreme conditions, but mining can harm them by releasing toxic metals, changing water acidity, burying or harming bottom-dwelling life, and disrupting food sources. These changes can harm many species that rely on these environments.
Waste materials
Mining processes create a lot of waste materials called tailings. These materials are what remain after valuable parts of the ore are removed. Tailings are made of water, sand, clay, and leftover bitumen. They are stored in tailings ponds, which are either natural valleys or man-made dams and walls. These ponds can be used for 30–40 years to let tailings settle or to reuse water.
Tailings can harm the environment by releasing toxic metals through acid mine drainage or by harming water life. This means water near the ponds must be checked and treated regularly. The biggest danger from tailings ponds is if the dam breaks. Tailings ponds are built using materials from nearby mining areas, and the dam walls are made strong to hold more tailings. Weak rules for designing these ponds increase the risk of flooding and environmental harm.
Some heavy metals in tailings, like thorium, can increase cancer risk. At China's Bayan Obo mine, tailings contain 70,000 tons of thorium. Contaminated groundwater is moving toward the Yellow River because the tailings dam lacks a waterproof layer.
A spoil tip is a pile of waste rock and soil removed during mining. These materials may contain chemical waste. Spoil tips are different from tailings because they are not processed ore. Spoil tips can catch fire easily, especially older ones, because they are made of flammable materials. Fires can start from sparks or hot ashes and may burn for many years underground or within the piles.
Effects of mine pollution on humans
Mining affects humans in many ways. Pollutants released during mining can cause serious health problems. For example, during smelting processes, large amounts of air pollutants like tiny particles, sulfur compounds, arsenic, and cadmium are released into the air. Metals are often released as tiny particles in the air as well. Miners also face many health risks, such as respiratory and skin diseases, including asbestosis, silicosis, and black lung disease.
Water pollution from mining is a major concern. About 30% of the world’s population has access to renewable freshwater, which is used by industries that produce large amounts of waste containing chemicals. These chemicals can enter freshwater sources and harm human health by accumulating in water and fish. A study of the abandoned Dabaoshan mine in China showed that even after many years of being inactive, metals from the mine still polluted nearby water and soil, affecting neighboring villages. In Brazil, a study of the Tapajos basin found that 75% of people tested had unsafe levels of mercury in their blood. Poor waste management around mining sites has led to an estimated 56% mortality rate in nearby areas, with many people diagnosed with esophageal and liver cancer. The mine continues to harm human health through crops, showing the need for better cleanup efforts.
Long-term air pollution causes many health issues, such as chronic asthma, lung problems, and heart-related deaths. A study in Sweden found that long-term exposure to air pollution may increase the risk of diabetes. Air pollution also harms health early in life, causing problems like respiratory issues, heart conditions, mental health issues, and complications during pregnancy, which can lead to infant deaths or chronic diseases in adulthood. Air pollution mainly affects people in large cities, where vehicle emissions are a major source of poor air quality. Harmful haze from pollution can be deadly to nearby communities. The spread of pollutants depends on factors like weather conditions and wind patterns.
Deforestation
Open-pit mining requires removing topsoil and rocks, which may cover forests, before mining can begin. Even though the amount of forest cleared by mining may be small compared to the total forest area, it can cause species to become extinct if those species are found only in that specific area.
Strip mining can harm landscapes, forests, and animal homes near mining sites. Trees, plants, and topsoil are removed from the mining area, which stops forests from growing again. After mining stops, the loss of plants and soil continues to harm the environment because it makes it harder for plants and animals to return to the area. Even legal mining, which follows environmental rules better than illegal mining, still contributes to some of the deforestation in tropical countries.
Open-pit mining for nickel has caused environmental damage and pollution in countries like the Philippines and Indonesia. In 2024, nickel mining and processing were major causes of deforestation in Indonesia. Open-pit mining for cobalt has also led to deforestation and loss of animal homes in the Democratic Republic of Congo.
Impacts associated with specific types of mining
Coal mining affects the environment in several ways, including air pollution, water contamination, and land use changes. Burning coal releases harmful substances such as mercury, lead, sulfur dioxide, nitrogen oxides, and heavy metals into the air. These pollutants can cause breathing problems in humans and harm wildlife that depends on clean air. The future of air pollution is uncertain because while the Environmental Protection Agency has worked to reduce some emissions, it does not have solutions for all coal plants. Water pollution also occurs during coal mining, as coal ash is often carried by rainwater into larger water sources. Cleaning water contaminated by coal waste can take up to 10 years, making it harder to purify water for use.
Deep sea mining for resources like manganese nodules has raised concerns among scientists and environmental groups. These activities may harm delicate ocean ecosystems, but scientists know less about the effects because there is limited research on deep sea life.
Lithium is not found as a pure metal in nature because it is highly reactive. Instead, it is found in small amounts in rocks, soil, and water. Extracting lithium from rock can expose it to air, water, and soil. Lithium is in demand for batteries used in manufacturing, but the chemicals involved in its production can harm humans, soil, and marine life. Between 2000 and 2007, lithium production increased by 25% due to battery demand. Most lithium comes from saltwater lakes, though it is also found in 150 types of minerals, clays, brines, and seawater. Extracting lithium from rock is more expensive than extracting it from brines, but brine deposits are usually larger than rock deposits.
Phosphate-bearing rocks are mined to produce phosphorus, which is used in industry and agriculture. Mining removes surface vegetation, exposing phosphorus rocks to the environment and causing land erosion. Mining produces waste materials and tailings, which can release toxic elements like cadmium, chromium, zinc, copper, and lead. These substances can harm human health through inhalation or contact.
Oil shale is a type of rock that contains kerogen, a substance from which hydrocarbons can be extracted. Mining oil shale harms the environment by damaging ecosystems and producing waste, including carbon dioxide and greenhouse gases. Environmentalists oppose oil shale production because it releases large amounts of greenhouse gases. Water contamination is a major issue due to the chemicals involved in oil shale processing. Mining also changes landscapes and causes long-term ground instability from underground mining. Some areas may become suitable for plant growth, but land rehabilitation may be needed.
Mountaintop removal mining involves cutting down trees and using machines and explosives to remove coal. This process makes the land more prone to flash flooding and can pollute water with chemicals. Mining disrupts the natural environment, leading to poor water quality in streams that affect both land and marine ecosystems. It also changes how water flows through the environment and impacts long-term watersheds.
Sand and gravel mining creates large pits and cracks in the Earth’s surface. Mining can reach deep enough to affect groundwater, springs, and underground wells. Major risks include erosion, river changes, and increased water turbidity, which makes water cloudy. In Lake Hongze, one of China’s largest freshwater lakes, sand mining has increased water turbidity in many areas.
Mitigation
Mining can harm the environment, but different methods are used to reduce this harm. The method chosen often depends on the type of environment and how serious the damage is. To make sure mining areas are restored for future use, many governments require mining companies to put money into a safe account. This money is kept until it is clear that the land has been successfully restored. However, if cleaning up the land costs more than the money in the account, the money might not be used. Successful restoration depends on government rules, available money, and the use of new technology. Since 1978, mining companies in the United States have restored over 2 million acres (8,000 km²) of land. This restored land now has plants and animals, and some areas are used for farming and raising livestock.
Specific sites
- Tui Mine located in New Zealand
- Stockton Mine located in New Zealand
- Northland Pyrite Mine located in Temagami, Ontario, Canada
- Sherman Mine located in Temagami, Ontario, Canada
- Ok Tedi Mine located in Western Province, Papua New Guinea
- The Berkeley Pit
- Wheal Jane Mines