Land Pollution: The Dark Side Of Mining Activities

Mining is an inherently invasive process that causes environmental damage at all levels, from local to global. It is a significant contributor to land pollution, with the potential to release harmful substances into the air, water, and soil, leading to soil erosion, water contamination, and the destruction of natural landscapes. The impact of mining operations on the surrounding land depends on the ecological setting of the mining sites, with some areas being more vulnerable to long-term ecological damage. While international regulations have reduced pollution from mining, it remains an issue in developing countries with illegal small-scale operations.

Strip mining and deforestation

Mining operations have a significant impact on the environment, and despite strict international regulations, they continue to cause land pollution in many parts of the world. One of the most prominent issues associated with mining is land use change, which includes not only the drilling and excavation of open-pit mines but also the development of surrounding infrastructure. This is particularly evident in the case of strip mining and deforestation, where large areas of forest are cleared to access the desired ore.

Strip mining is a type of surface mining where the top layers of soil and vegetation are removed to expose the ore below. This process can have detrimental effects on the environment if the mined area is not properly reclaimed after mining activities cease. Proper reclamation includes replacing and grading the soil and replanting vegetation. Without these measures, the exposed area is susceptible to erosion, and the risk of chemical reactions that can lead to water pollution increases.

The mixing of air, water, and sulfur-containing rocks, for example, can result in the formation of sulfuric acid and iron hydroxide. This acidic runoff can dissolve heavy metals such as copper, lead, and mercury, which then contaminate nearby streams and water bodies. In fact, water seeping out of abandoned mines can become highly acidic and contaminated with these metals, causing significant ecological damage, as seen in Colorado and the mid-Atlantic and Appalachian regions of the United States.

Forestry practices, such as clearcutting and the use of "skid trails", can also contribute to land pollution. These activities expose the soil, making it more vulnerable to erosion. Additionally, the improper construction and use of skid trails, which are temporary paths created to transport logs out of the forest, can further increase the risk of erosion, especially when constructed against the natural contour of a hillside.

The impact of mining on deforestation is significant, as evidenced by the Brazilian Amazon, where mining activities contributed to nearly 10% of deforestation between 2005 and 2015. This figure is even more striking when considering that it includes not only the deforestation caused by the mines themselves but also the ancillary infrastructure, such as roads, staff housing, and airports. The issue of mining-induced deforestation extends beyond the Brazilian Amazon, with similar concerns raised about the tropical rainforests of Gabon and the need to conserve biodiversity and regulate climate through reducing tropical deforestation.

Soil erosion and water pollution

Eroded materials, such as sediment, can be transported by runoff into nearby water bodies, leading to sedimentation. This process degrades water quality, causes habitat loss, and inflicts long-lasting ecological damage. Additionally, altered drainage patterns can redirect water flow, intensifying erosion and sedimentation in nearby water bodies.

The impact of mining on water pollution is also significant. Mining consumes, diverts, and pollutes water resources. Water pollution can occur through discharged mine effluent, seepage from tailings and waste rock impoundments, and the release of toxic chemicals used in mining processes. These chemicals, such as cyanide and sulfuric acid, can spill, leak, or leach into nearby water bodies, posing toxic threats to humans and wildlife.

Furthermore, abandoned subsurface mines can contribute to water pollution. Water seeping out of these mines can become highly acidic and contaminated with heavy metals such as copper, zinc, and arsenic. This acidic runoff can dissolve heavy metals and contaminate streams and other water bodies, rendering them devoid of life.

While international regulations have reduced pollution from mining, it remains an issue in developing countries with illegal small-scale operations, known as 'artisanal mining'. The environmental problems associated with mining include land use change, deforestation, and the emission of air pollutants and greenhouse gases.

Air pollution and health issues

Mining operations have a significant impact on air quality and, consequently, on the health of miners and surrounding communities. The extraction and processing of minerals, metals, and coal release fine particles and toxins into the air, contributing to air pollution and respiratory health issues.

During the mining process, blasting, excavation, and transportation release fine particles into the air, which may contain heavy metals and other pollutants. This mining dust affects air quality and the respiratory health of nearby residents. Additionally, the removal of vegetation and deforestation required for mining expose the soil to erosion, further contributing to air pollution as precipitation carries away loose topsoil.

Metal mining, in particular, is a significant source of air pollution. For instance, the smelting of metals, including gold, releases arsenic and other toxins. According to the U.S. Toxics Release Inventory, the metal mining industry in the United States was responsible for 92% of industrial mercury emissions, 94% of industrial arsenic emissions, and 73% of known carcinogenic waste in 2010. Exposure to mercury can lead to impaired vision, muscle weakness, and permanent kidney and nerve damage. Arsenic is a carcinogen. And high zinc exposure is also associated with various health risks.

Coal mining also contributes to air pollution and climate change. The burning of coal increases air pollution, adding toxins such as mercury, lead, sulfur dioxide, nitrogen oxides, and other heavy metals to the atmosphere. These pollutants cause breathing difficulties and impact the wildlife and ecosystems surrounding coal-mining sites.

The health consequences of air pollution from mining activities are significant and wide-ranging. A Swedish cohort study suggests that long-term exposure to air pollution may induce diabetes. Additionally, early-life exposure to air pollution has been linked to respiratory, cardiovascular, mental, and perinatal disorders, leading to increased infant mortality and chronic diseases in adulthood. The mortality rate within regions around mining sites is estimated to be 56%, with diagnoses of esophageal and liver cancer prevalent.

To mitigate these health risks, it is essential to prioritize environmental standards and regulations in mines to reduce pollution. Enhancing air quality monitoring and implementing sustainable mining practices are crucial steps to protect the health of miners, surrounding communities, and the broader environment.

Habitat loss and biodiversity

Mining has a significant impact on biodiversity, affecting it at multiple spatial scales (site, landscape, regional, and global) through direct and indirect processes. Direct impacts include mineral extraction, which can lead to habitat loss and degradation. Site preparation for mine expansion and waste management is a destructive process, changing abiotic and biotic conditions and, in some cases, single-handedly causing region-wide declines in rare and threatened species and ecosystems.

Indirect impacts occur when mining facilitates additional biodiversity loss. For example, mining-associated infrastructure development can attract human populations, causing new threats or exacerbating existing ones, such as over-exploitation (e.g., hunting, fishing), invasive species, and increased pollution.

The environmental impact of mining can occur at local, regional, and global levels through direct and indirect mining practices. Mining can cause erosion, sinkholes, and the contamination of soil, groundwater, and surface water by chemicals emitted from mining processes. These chemicals include mercury, arsenic, lead, and cyanide, which are used to extract gold and are released from oxidized minerals when ores are exposed to air.

Habitat destruction is one of the main issues of mining activity. Huge areas of natural habitat are destroyed during mine construction and exploitation, forcing animals to leave the site. This destruction of forest ecosystems, for example, displaces numerous birds, mammals, and insects, forcing them to migrate and often leading to conflicts with human settlements and other species.

The decline in wildlife populations caused by mining can lead to ecological imbalances, affecting soil health, climate regulation, and the resilience of natural disasters. Protecting endangered species and maintaining biodiversity is crucial for environmental health and human well-being. Sustainable mining practices and stringent regulations are essential to mitigate these impacts and preserve the planet for future generations.

Technological advancements in the mining sector can reduce the impacts of extraction through lower land-use methods such as in-situ leaching. However, technology can also pose additional threats from chemical pollution and must be carefully monitored for its potential costs and benefits for biodiversity conservation.

Illegal mining operations

Illegal mining is the extraction of precious metals without following the proper procedures to participate in legal mining activity. These procedures include permits and licences for the exploration of the land. Illegal mining is often undertaken by criminal groups and is considered a corruption of privately owned large-scale mining and artisanal small-scale mining operations.

Artisanal small-scale mining operations are labour-intensive as miners do not use machinery to extract the metals. Informal mining occurs when artisanal small-scale mining operations proceed without the proper legal licences. These operations are still illegal, but they are not an indictable offence like the criminal groups that organise illegal mining operations.

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