Mining can affect the environment in many ways, both near the mining site and far away. It 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 helps cause 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 people's health. In some countries, mining companies must follow strict rules to restore mined areas to their original condition. While mining can offer benefits to communities, it can also lead to disagreements, especially about how land is used above and below the ground.
Mining operations often cause major changes to local ecosystems and have long-term effects on the planet's health. To build mines and related structures, large areas of land are cleared, using a lot of energy and water. This process also releases air pollutants 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% rise in less than 20 years. This increase puts Earth's natural resources under great stress. 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 major example is the Ok Tedi Mine in Papua New Guinea. Soil erosion can reduce the amount of water available for plants to grow, causing a decline in plant populations.
Soil erosion happens when mining activities, such as digging and blasting, disturb natural areas. These actions damage tree root systems, which are important for holding soil in place and preventing erosion. Eroded soil can be carried by water runoff into nearby rivers and lakes, creating sediment buildup. Changed water flow patterns from mining also increase erosion and sediment buildup in water bodies. Over time, these effects harm water quality, destroy animal homes, and cause lasting damage to ecosystems.
Sinkholes
A sinkhole near a mine is usually caused by the collapse of the mine roof after removing resources, weak layers of soil or rock above the mine, or cracks 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 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 very dangerous for people and buildings. To reduce the risk of sinkholes, mine designs should include strong supports and walls around areas likely to sink. Empty spaces in old mine tunnels can be filled with materials, and special liquids called grout can be used to make the ground more stable.
Water pollution
Mining can harm nearby surface and groundwater. If steps are not taken to protect water, very high amounts of harmful chemicals, like arsenic, cyanide, sulfuric acid, and mercury, can spread into large areas of water. Mining uses a lot of water for drainage, cooling, and other processes, which increases the chance that these chemicals will pollute groundwater and surface water. Mining also creates large amounts of wastewater, which is hard to dispose of safely 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. Putting waste deep underwater in the ocean is considered a better option. Storing waste on land and filling the mine after it is finished is even better, if forests do not need to be cleared for storage. Chemicals leaking into water systems can also harm the health of people living nearby.
In well-managed mines, scientists like hydrologists and geologists carefully test water to prevent contamination from mining activities. In the United States, federal and state laws require mining companies to follow rules that protect surface and groundwater from pollution. This is best done by using safe extraction methods, such as bioleaching. Protection from water pollution should also continue after a mine is closed, because water systems can still become polluted years later.
Air pollution
The mining industry is responsible for 4 to 7% of all greenhouse gas emissions worldwide. Greenhouse gases, such as carbon dioxide (CO₂) and methane (CH₄), are released during mining activities both directly and indirectly. These gases contribute to changes in the Earth’s climate.
Air pollution harms plant growth by interfering with how plants absorb resources. Pollutants like ozone (O₃) and nitrogen oxides (NOx) damage leaves and reduce the ability of plants to capture carbon dioxide through photosynthesis. Heavy metals, which are released into the soil, harm plant roots and reduce the ability of plants to take in water and nutrients. These effects change how plants use their resources, which can slow their growth. When air pollution combines with other challenges, such as drought, the impact on plants becomes more complex. At the ecosystem level, air pollution can change which plant species grow best in an area. The effects of pollution depend on the type and amount of pollutants present. In farming areas, these changes can lead to lower crop yields.
To reduce air pollution from mining, efforts often focus on using cleaner energy. Switching from coal and diesel to gasoline can lower greenhouse gas emissions. Using renewable energy, such as solar or hydropower, can further reduce emissions. Improving the efficiency of mining operations and studying the full environmental impact of mining can also help reduce pollution.
Sub-surface mining occurs below the water table, so water must be pumped out to prevent flooding. When a mine is closed, pumping stops, and water fills the mine. This water is the first step in acid rock drainage, a process that can occur naturally but is worsened by mining activities. Acid rock drainage happens when rocks containing sulfide minerals are exposed to air and water, creating acidic water. This can happen in areas disturbed by mining, construction, or transportation. In some places, water from coal waste is highly acidic and is called acid mine drainage (AMD). Similar problems can occur in areas with acid sulfate soils, which are found in coastal or estuarine regions.
Five main methods are used to manage water flow at mining sites: diversion systems, containment ponds, groundwater pumping systems, subsurface drainage systems, and subsurface barriers. For AMD, contaminated water is often pumped to a treatment facility to neutralize harmful chemicals. A 2006 review found that predictions about water quality after pollution control efforts often underestimated the actual harm to groundwater, streams, and rivers.
Heavy metals are naturally occurring elements with high density and atomic weight. They do not break down easily and can remain in the environment for long periods. They can build up in living organisms, which raises concerns about their effects on human health and ecosystems. Naturally occurring heavy metals are often in forms that are not easily taken up by plants, such as in minerals or complex structures. They also stick strongly to soil, making them hard for organisms to access. However, how heavy metals interact with soil and living things depends on soil conditions and the types of organisms present. Heavy metals from natural sources bind more strongly to soil than those from human activities.
Mining can cause environmental problems, such as the movement of heavy metals through runoff and groundwater. For example, the Britannia Mine, a former copper mine near Vancouver, Canada, and Tar Creek, an abandoned mining area in Oklahoma, have heavy metal contamination. At Tar Creek, water from the mine leaked into groundwater, polluting it with heavy metals like lead and cadmium. Heavy metals in water can change its chemistry by affecting pH, buffering capacity, and oxygen levels. Storing mining waste, such as tailings and dust, can lead to pollution if wind carries it away, as seen at Skouriotissa, an abandoned copper mine in Cyprus. Environmental changes, such as global warming and increased mining, may raise heavy metal levels in stream sediments. These effects are often more severe in areas downstream from pollution sources.
Effect on biodiversity
Mining affects biodiversity in many ways, both near and far from the mining site. Close to the mine, habitats are destroyed directly when land is cleared for mining. On a larger scale, mining causes problems like pollution and climate change, which harm the environment across regions and even the whole world. To protect biodiversity, conservation efforts must address both the immediate damage at mining sites and the long-term environmental effects. Building a mine changes the habitat greatly, and smaller changes can spread over a large area. For example, waste from the mine can pollute the environment for a long time. Even after mining stops, the damage can last for many years. Destroying or changing the original habitat is the main reason biodiversity is lost, but harmful effects from mine materials can also poison animals, plants, and microorganisms through direct contact or through food and water. Changes in habitat, such as pH and temperature, can harm nearby communities. Species that live only in specific areas are especially at risk because they cannot survive if their habitat is altered. Habitats can also be damaged by things like large rocks left behind from mining, which disrupt natural environments.
Heavy metal levels usually get lower as you move away from the mine, and the effects on biodiversity often follow the same pattern. How much harm is caused depends on how easily the contaminant moves through the environment 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.
Toxins from mining can build up more in animals higher up the food chain, even if the levels are not high enough to kill the organisms directly. This process is called biomagnification.
The harm mining causes to biodiversity depends on the type of contaminant, how much of it is present, and the kind of ecosystem it affects. Some species can survive pollution, while others may disappear completely from the area. Over time, the habitat may not fully recover from contamination. Cleaning up the damage takes a long time, and in most cases, the original variety of life before mining is not restored.
Mining can harm aquatic life in several ways. One way is direct poisoning, which is more likely if the pollutants can move through water or sediment. Mine drainage can change water pH, making it hard to tell if the harm is from the chemicals or the pH changes. Still, the effects of pH changes can be proven. High levels of sediment in water can block sunlight, reducing algae growth. Metal deposits can also cover algae or their surfaces, stopping them from growing.
Conditions in areas with acid mine drainage change over time, depending on factors like temperature, rainfall, pH, salt levels, and metal amounts. These changes can affect how much metal is available for organisms to absorb. Contamination can last for many years. For example, even 90 years after a mine closed, water pH remained very low, and only acid-loving bacteria survived.
One major example of mining harm was in Minamata Bay, Japan. Methylmercury from an industrial chemical company polluted the water, leading to a disease called Minamata disease. This caused mercury poisoning in fish and shellfish, which harmed other animals and people who ate the contaminated seafood. Another example is the impact of phosphate mining on coral reefs near Christmas Island. Runoff from the mine carried high levels of phosphate to nearby reefs, reaching some of the highest levels ever recorded in Australian reefs. This led to a decline in important reef-building species like corals and algae, likely because the phosphate helped fast-growing algae outcompete these species.
Algae communities in water with high zinc levels are less diverse, and mining pollution can reduce their ability to produce food. Diatoms, a type of algae, are greatly affected by changes in water chemistry, pH, and metal levels. In very polluted areas, algae and plankton populations may drop significantly. Zooplankton, which eat plankton, are also harmed by severe mining effects. However, in some cases, the total amounts of phytoplankton and zooplankton might stay the same even if their types change.
When studying the risks of mining to ocean life, it is important to consider other vulnerable communities, such as those on the seafloor, which can be harmed by deep-sea mining. Microbial life is essential for many processes in seafloor ecosystems. Deep-sea mining often happens near hydrothermal vents, where minerals like sulfides are found. Other mining areas include inactive vents, manganese-rich formations, and cobalt crusts on seamounts. These areas support life in extreme conditions. As mining increases, it may harm microbial communities and the services they provide. Possible harms include acidification, heavy metal pollution, loss of slow-growing sea creatures, burial of organisms by sediment, and disruption of food sources. These changes can harm the balance of life in these environments, leading to declines in species that rely on hydrothermal vents.
Waste materials
Mining processes create extra waste materials called tailings. These materials remain after valuable parts of ore are separated from less valuable parts. Tailings are a mix of water, sand, clay, and leftover bitumen. They are stored in tailings ponds, which are either natural valleys or large man-made dams and walls. These ponds can stay in use for 30–40 years, allowing tailings to settle or for water to be reused.
Tailings can harm the environment by releasing toxic metals through acid mine drainage or by harming water life. Water near tailings ponds must be closely watched and treated to prevent damage. The biggest danger from tailings ponds is dam failure. These ponds are built using soil, waste, or rock from mining, and the dam walls are designed to hold large amounts of tailings. Poor rules for building tailings ponds increase the risk of flooding and environmental harm.
Some heavy metals in tailings, like thorium, can raise 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 barrier to stop water from leaking.
A spoil tip is a pile of overburden removed during mining for coal or ore. This waste includes soil and rocks that may contain chemical waste. Spoil tips differ 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, hot ashes, or other sources and may burn for years underground or within the pile.
Effects of mine pollution on humans
Mining affects humans. Many diseases can occur because of pollutants released into the air and water during mining. For example, during smelting processes, large amounts of air pollutants, such as tiny particles, sulfur dioxide, arsenic, and cadmium, are released. Metals are often released into the air as small particles. Miners also face health risks at work. Many miners develop breathing or skin problems, such as asbestosis, silicosis, or black lung disease.
Water pollution from mining causes poor water quality. About 30% of the world’s population has access to renewable freshwater used by industries that produce waste with chemicals. These chemicals can enter freshwater and harm human health by building up in water and fish. A study of the abandoned Dabaoshan mine in China showed that even after many years, metals from the mine remained in water and soil, harming nearby villages. In Brazil’s Tapajos basin, 75% of people tested had unsafe levels of mercury in their blood. Poor waste management near mining areas is linked to about 56% of deaths in those regions. Many people have been diagnosed with esophageal cancer and liver cancer. The mine still harms human health through crops, showing the need for cleanup efforts.
Long-term air pollution can cause chronic asthma, breathing 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 breathing, heart, mental, and pregnancy-related issues, which can lead to infant deaths or long-term health problems in adults. Air pollution mainly affects people in large cities, where vehicle emissions worsen air quality. Harmful haze from pollution can be deadly to nearby communities. How poisons spread depends on weather conditions, such as air stability and wind.
Deforestation
Open cast mining requires removing the overburden, which may include forests, before mining can begin. Even though deforestation from mining might be small compared to the total area, it can cause species to become extinct if many species are found only in that area.
Strip mining can harm landscapes, forests, and wildlife habitats near mining sites. Trees, plants, and topsoil are removed from the mining area, which stops forests from growing. After mining ends, environmental damage continues because the loss of plants and soil makes it difficult for natural ground cover to return to the area. Legal mining, although better controlled than illegal mining, still causes a significant amount of deforestation in tropical countries.
Open-pit nickel mining has caused environmental harm and pollution in countries like the Philippines and Indonesia. In 2024, nickel mining and processing were major causes of deforestation in Indonesia. Open-pit cobalt mining has led to deforestation and loss of animal homes in the Democratic Republic of Congo.
Impacts associated with specific types of mining
The environmental effects of the coal industry include air pollution, water management challenges, and land use changes. Burning coal releases harmful substances such as mercury, lead, sulfur dioxide, nitrogen oxides, and heavy metals. These pollutants cause breathing problems and harm wildlife that depends on clean air. The future of air pollution remains uncertain because the Environmental Protection Agency has limited control over all coal-related emissions. Water pollution occurs during coal mining, as coal waste is often washed into larger water sources by rain. Cleaning water sites affected by coal waste can take up to 10 years, making it harder to purify water.
Deep sea mining for resources like manganese nodules has raised concerns among scientists and environmental groups. Limited research on deep sea life makes it difficult to fully understand the potential impacts on these fragile ecosystems.
Lithium is not found as a pure metal because it reacts strongly with other elements. 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 widely used in batteries, but its production can release toxic chemicals that harm humans, soil, and marine life. Lithium production increased by 25% between 2000 and 2007, and major sources include brine deposits in salt lakes. Lithium is found in 150 different minerals, clays, brines, and seawater. Extracting lithium from rock is more expensive than extracting it from brine, but brine deposits are generally larger than rock deposits.
Phosphate-bearing rocks are mined to produce phosphorus, a key element in industry and agriculture. Mining removes surface vegetation, exposing phosphorus rocks and damaging land, which can lead to erosion. Mining produces waste and tailings, which can release harmful particles and toxic elements like cadmium, chromium, zinc, copper, and lead.
Oil shale is a type of rock that contains kerogen, a substance that can be turned into hydrocarbons. Mining oil shale harms the environment by damaging ecosystems and land. Heating and burning oil shale produce waste and greenhouse gases like carbon dioxide. Environmentalists oppose oil shale production because it releases large amounts of greenhouse gases. Water contamination is a major issue due to the interaction of oil shale with oxygen and hydrocarbons. Mining changes the landscape and can cause long-term ground instability from underground mining. Some areas may support plant growth, but 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 pollution from chemicals. Disturbed land from mining harms water quality in streams, affecting both marine and terrestrial ecosystems. It also changes how water moves in the environment over long periods.
Sand and gravel mining creates large pits and cracks in the Earth's surface. Mining can reach deep underground, affecting groundwater, springs, and wells. Major risks include erosion, river changes, and increased water turbidity. For example, sand mining near Lake Hongze in China has made the water more cloudy, harming the lake's environment.
Mitigation
Different methods are used to reduce the harm that mining causes to the environment. The method chosen often depends on the type of environment and how serious the damage is. To make sure that land is properly restored after mining, many governments and regulatory authorities require mining companies to place money in a secure account. This money is kept until the restored land is shown to be successfully used again. However, if the cost of cleaning up the land is higher than the amount in the account, the money might not be used. The success of these restoration efforts also depends on government rules, available resources, and the use of new technology. Since 1978, the mining industry in the United States has restored over 2 million acres (8,000 km) 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