The mining industry has been a prominent part of the global economy for many decades. The extraction of mineral resources makes the mining sector important to many industries, from our use of metals to lithium for batteries to power our devices. While its resulting products and resources are now common, the mining process has negative environmental and social impacts.
Negative impacts of mining cut across all levels, from local to regional and global. It also affects humans, birds, and terrestrial and aquatic animals. In this article, we’ll explore the environmental impact of mining-related activities and dissect the effects of mining operations on ecological systems and natural conditions. It also delves into its impact on the world in which humans and all biota live.
The Global Mining Industry
Mining is the extraction of useful mineral resources from the earth and sea. The business of the mining industry is extracting precious minerals and other geological materials. Mined substances are those we can’t derive or produce through agricultural processes or manufacturing in a laboratory or industry.
The extracted minerals are inorganic substances occurring in nature with specific physical properties or molecular structures and precise chemical compositions. Minerals in the earth mix with other unwanted rocks minerals. However, they are only valuable in their pure forms.
The pure mineral form comes from the processing and refining of extracted substances to separate them from unwanted rocks and other minerals. Transforming these extracted substances into valuable materials boosts economies where they are mined and processed.
Additionally, the total quantity of minerals present in a deposit is the mineral inventory. On the other hand, the quantity that is mineable for profit is the ore reserve.
Some examples of substances we extract are gold, iron ore, copper, coal, oil shale, limestone, rock salt, and potash.
Mining is an important industry and one of the biggest contributors to the global economy. The development of mining industries impacts the resource acquisition potential and economic growth of a country. This makes it one of the most important earning sources of a country rich in mineral reserves that the mining industry can profitably extract.
Statistics show that the revenue of the leading 40 global mining companies, which represent the majority of the worldwide mining industry, summed up to 656 billion U.S. dollars in 2020.
Anything but new
Furthermore, the inception of the mining industry dates back to prehistoric times. The first mineral mined was flint, which was ideal for scrapers, knives, and arrowheads due to the natural pattern that makes it easy to break into sharp-edged shards. Also, metal mining of gold, ochre, and malachite - the copper mineral, dates back to prehistoric times, during the Neolithic Period or Stone Age.
Mining Industry Classifications
The mining industry falls under two classifications of industries, either the geophysical or chemical industry. This classification depends on the characteristics of the mining industry, with the relative depth of the mineral deposit and the economic value of the mineral all playing vital roles in determining the mining technique.
In addition, mining techniques have two categories. The first is the excavation type, which consists of surface, subsurface, or underground mining. The second is the target material category consisting of placer mining and in situ mining. Below we briefly explore the techniques of mining:
- Surface Mining
- Underground Mining
- In Situ Mining
- Placer Mining
Surface mining is extracting minerals close to the surface of the earth. It involves removing the vegetation on the surface, dirt, and even layers of bedrock. The purpose is the extraction of buried oil deposits.
Surface mining is a broad category of mining involving the removal of soil and overlying rock of a mineral deposit. Miners use surface mining to extract the most commonly mined minerals like coal, iron, and bauxite. This mining type has different techniques like strip mining, mountaintop removal mining, high wall mining, dredging, and open pit mining.
Open pit mining involves digging a large land area and bringing the ore to the surface using a conveyor belt. The extraction of gold, silver, and copper involves this technique.
Strip mining involves clearing vegetation and rocks on the land's surface before the extraction. Its usage is primarily for extracting coal and other hard minerals.
Mountaintop removal mining removes the top of the mountain and extracts the ore at the depth of the mountain.
Today, surface mining accounts for the extraction of two-thirds of the world's solid minerals. Its usage is predominant in obtaining gravel, crushed stone, sand, coal, phosphate, copper, iron, and aluminum. Moreover, many miners often prefer surface mining to underground mining because it’s cheaper and has fewer complications. It’s also safer in terms of electricity and water.
In contrast to surface mining, which undertakes the removal of surface terrain and overlying rocks, underground mining removes mineral deposits through shafts and tunnels. The overlying rock is left in place.
Underground or subsurface mining consists of excavating deep below the earth's crust at the location of the mineral resources. It involves digging subversive tunnels and rooms below the ground surface. Miners make use of devices such as drill rigs to dig through the rock and extract the oil from an already-dug tunnel.
Compared to surface mining, this mining method is expensive and dangerous. As a result, miners use it mainly in situations where there is a narrow vein concentration of valuable ores like gold.
There are different underground mining techniques when extracting valuables like coal, diamonds, and ore. Miners employ different techniques in hard and soft rock formations. A significant advantage of subsurface mining over surface mining is its possibility of underwater excavation.
In Situ Mining
In situ leaching (ISL), also known as in situ recovery (ISR) or solution mining, is the technique of extricating valuable minerals from ores. This extrication is done without extracting the mix of ore and rocks to the surface for processing.
The technique involves injecting chemicals into an ore deposit to soften the metal and allow it to flow to the surface. ISR involves dissolving a mineral deposit in the ground and then processing it at the surface without excavating any rock.
In situ mining is often considered more environmentally friendly because it creates minimal noise, dust, and greenhouse emissions. It also causes minimal physical disruption and is cost-effective. Its usage is common in recovering uranium, gold, silver, zinc, lead, and other metals. Studies recorded that in 2019, 57% of world uranium mined was by in situ leaching.
The name placer comes from the Spanish word “placera,” meaning “alluvial sand.” Placers are particles that form from the exposure of sedimentary rock layers to the earth's surface due to tectonic movements.
Placer is a deposit of loosely distributed gravel that contains precious metals like gold or other heavy metals. We can find these placers in alluvial deposits, rock, sand, and gravel sediments in modern or ancient stream beds.
Placer mining is the method of retrieving valuable mineral deposits from loose river sediments. Experts use it to sift out valuable metals from sediments in river channels, beach sands, or other environments.
This mining technique mines precious metal deposits (mainly gold and gemstones) and ranges from small-scale gold mining on-site to larger-scale industrial-sized operations.
The placer mining technique is common in habitats with a natural accumulation of sediments. It’s also common in river beds and sands. Examples of minerals miners collect using placer mining include platinum, diamonds, and tin. Moreover, choosing any of these mining techniques depends on some considerations. These considerations include the site of the mineral deposits and the economic value of the deposit. Others are the chemical composition of the deposit and also environmental considerations.
Environmental Impacts of Mining Operations
Even though mining contributes significantly to the global economy, mining operations have a negative environmental impact. These impacts occur both before and after mining activity. In response, most of the world's countries have enacted regulations to decrease the impact.
However, owing to the ongoing demand for extracted mineral deposits, full enforcement of such regulation is impossible. Mining has the potential to release harmful substances into the air and water and can lead to soil damage. Also, it pollutes water and air, harms wildlife and nature, and permanently disrupts natural landscapes. Research reveals that over 40% of streams in Western watersheds are contaminated by acid mine drainage and heavy metals3.
Environmental impacts of mining operations occur at all levels and affect areas beyond mining sites. It occurs at the local, regional and global levels through direct and indirect mining techniques. These impacts lead to erosion, loss of biodiversity, and sinkholes. It also causes contamination of soil, soil water, and surface water through chemical releases during the mining process.
What are the negative impacts of mining?
Mining exploration and activities can affect the environment in numerous ways. These ways are:
- Water Pollution
- Air Pollution
- Land Pollution
- Effect of Mining on Wildlife and Biodiversity
- Effect on Human Health
Mining causes water pollution through acid mine drainage and increasing sediment levels in water bodies. Waste materials are environmental evidence of the role mining plays in water contamination.
Acid drainage is the leakage of sulphuric acid formed as a result of exposure to air of sulfide from ore mined into streams. This is the primary source of groundwater pollution from mining. Acid rock drainage occurs for decades and centuries, even after mining activities have ceased. Also, chemicals for dissolving ores, such as cyanide, sulfuric acid, arsenic, and mercury, find their way into streams and oceans, contaminating water bodies.
When there are increases in the concentration of toxic chemicals in streams and oceans, it poses a threat to aquatic animals. It also affects terrestrial species that depend on these animals for food.
Moreover, modern mining techniques consume high amounts of water for extraction, processing, and wastewater. Mining utilizes large quantities of water for mine drainage, mine cooling, aqueous extraction, and other mining processes. This high water consumption affects the availability and supply of water in the mine area.
Also, toxic wastewater from the extraction process and tailing ponds pollute water sources nearby. It also exhausts the clean water supply in the region close to the mine. Consequently, water pollution adversely affects domestic water supply, irrigation, swimming, and other activities that depend on water resources. It affects nearby ground and surface water.
Related: Read more water pollution facts.
Mining operations at a mine site affect air quality in the atmosphere. During mining, there is excavation, crushing, and moving of tons of rocks, all of which significantly increase the amount of dust and particles in the air.
Metal smelting also leads to the release of pollutants like sulfur dioxide. The release of unrefined materials into the air during the exposure of mineral deposits on the surface through mining is inevitable. Wind erosion and traffic from vehicles and other mining infrastructure make these materials airborne. These materials are associated with health problems. Further, all that machinery burns fossil fuels, emitting carbon dioxide and other greenhouse gas emissions.
The lung tissue can absorb materials like riebeckite, lead, arsenic, cadmium, and other toxic metals. This causes problems like pneumoconiosis and silicosis, commonly known as black lung. Also, inhaling these particles trigger allergies in humans. The long-term effects of air pollution from mining1 include pulmonary insufficiency, chronic asthma, and cardiovascular immortality.
Furthermore, air pollutants harm plant growth. Air pollutants such as heavy metals in the soil affect the functioning of roots at first. It then later interferes with the production of carbohydrates through photosynthesis. This consequently affects plant growth through changes in the allocation of resources to the various plant structures. It also shows an aspect of how toxic materials can seep into the food chain.
Related: Read more air pollution facts
Since mine operations involve extracting mineral deposits from the soil, the ground for the excavation will suffer some damage. Mining is an innately invasive process that causes destruction and damage to a landscape larger than the mining site itself. The effect of mining on land continues even after mining is over and the mining site closure.
Digging landscapes for extraction destroys the land's physical properties at the mining site. The removal of soil layers and unearthing of soil in open pits destabilize the ground and cause subsidence and soil erosion. This threatens the future of roads and buildings on such lands in the future.
When mining affects the landscape, restoring it often requires a long time. In some cases, it never recovers.
Related: Read more land pollution facts
Effects of Mining on Wildlife and Biodiversity
Part of mining's environmental pollution problem is that it causes a loss of biodiversity. Mining leads to habitat loss for several animals, ranging from wildlife species to microorganisms. Also, it displaces indigenous animal species from their colony. It often affects indigenous animal species since even the slightest disturbance in their colony puts them at higher risk of extinction. In the worst case, toxins from mining can wipe out an entire population of sensitive species.
Mining is a heavy industrial activity that involves using heavy machinery for escalation. As a result, it dislocates wildlife and damages their habitats. It destroys the habitats of species like trout and others that depend on clear, cold, oxygen-rich water. This is a result of erosion and sedimentation.
In addition, aquatic animals, birds, and wildlife also suffer from water pollution caused by mining. Drinking contaminated water in ponds can poison them. Macroinvertebrates that aquatic animals consume often contain higher metal concentrations than surface water. This causes stunted growth for fish, if not death.
Human Health Risk Assessment
Besides mining pollution and its environmental damage, there are also human and community health impacts related to modern mines.
The U.S. Environmental Protection Agency publishes a public record of toxic waste and chemicals released via its Toxic Release Inventory (TRI), which finds that metal mining is the US’s leading toxic polluter.
Since water is indispensable to humans, surrounding human populations suffer from water pollution—mining waste and pollutants that end up in water cause poor water quality. In turn, this affects mining communities and the surrounding environment. Also, chemical deposits in water pose a great risk to human health as they accumulate in fish and water.
Apart from water pollution consequences, air pollution from mining also affects human health. Inhaling polluted air from mining activities is hazardous to our health. Many diseases result from water and air pollution discharges from the mining process.
For instance, while extracting ore, air pollutants like sulfide, cadmium, and arsenic particles make their way into the atmosphere. These can lead to various health effects like mental, cardiovascular, respiratory, and perinatal disorders. They result in infant mortality or chronic diseases in old age.
Furthermore, mining has many occupational health hazards and social impacts of mining and resource extraction. Miners suffer from respiratory and skin diseases such as black lung disease, silicosis - a lung disease resulting from inhaling crystalline silica dust, and asbestosis - an inflammatory lung disease caused by prolonged exposure to asbestos.
Many mined resources play an essential role in producing energy. Chemical industries also use them as raw materials. The mining industry works as the backbone for many other industries. The industry is significant to the economy despite the environmental impacts of mining activities and mine sites on social and environmental systems.
As we have outlined above, there are many reasons why mining is a problem. The negative impact of mining activities on the environment is its major shortcoming. Owing to its importance to industries, we can’t abolish it.
This is why mining companies need to adhere to environmental management codes that champion responsible and sustainable development in mining2. We can ensure the restoration of the mining regions, curb environmental problems and embrace responsible mining. These ensure the careful use of natural resources while establishing a safer society.
Entwistle, J.A., Hursthouse, A.S., Marinho Reis, P.A. et al. Metalliferous Mine Dust: Human Health Impacts and the Potential Determinants of Disease in Mining Communities. Curr Pollution Rep 5, 67–83 (2019). https://doi.org/10.1007/s40726-019-00108-5
Gavin Hilson, Barbara Murck, Sustainable development in the mining industry: clarifying the corporate perspective, Resources Policy, Volume 26, Issue 4, 2000, Pages 227-238, ISSN 0301-4207, https://doi.org/10.1016/S0301-4207(00)00041-6
Liquid Assets 2000: America's Water Resources as a Turning Point (pdf), United States Environmental Protection Agency, May 2000