The mining sector supplies essential raw materials for domestic and industrial purposes, such as renewable energy technologies, modern electric vehicles, and novel energy storage systems. However, mining inherently disrupts the natural environment. Poorly regulated, large-scale operations can cause habitat destruction, pollution, soil degradation, resource depletion, toxic waste, and community disruption.1 This makes it necessary to integrate sustainable technologies in the mining industry.
Image Credit: Favious/Shutterstock.com
What Makes Mining a Major Threat to the Environment?
Land degradation and deforestation
Mining activities pose long-term harmful effects on the biophysical environment, as well as the social, cultural, and economic systems. Among all the different types of pollution, land degradation has accelerated the most due to mining activities.
The extraction of minerals leads to deforestation, and mining activities may lead to soil erosion. This leads to damaged water resources, contaminated soils, and increased land pollution.2 A prime example is Mongolia, where 77% of the land is classified as degraded or deforested, according to UNDP. In urban areas of Mongolia, coal combustion is a major issue for soil pollution releasing significant amounts of metal(loid) into the environment.3
Water pollution
Water pollution is another well-known issue in mining. A naturally occurring process called Acid Rock Drainage (ARD) produces sulfuric acid continuously drained from the rocks by rainwater or surface drainage, contaminating nearby rivers. Acid Mine Drainage is the most common and problematic form of water pollution in mining. Heavy metal contamination occurs when metals like arsenic, cadmium, lead, and zinc are exposed to water bodies. These metals leach from the rock and run into nearby water sources, polluting them.
Heavy-duty equipment causes erosion
Moreover, heavy-duty equipment at mining sites causes significant erosion, increasing sedimentation in nearby water sources.4 Mining-related water pollution is severely dangerous for human health and destroys the aquatic ecosystem.
Air pollution
The mining industry, along with land and water pollution, is a major source of air pollution. The mining of coal is attributed heavily to polluting the air. The oxidation of coal also produces harmful gaseous pollutants that are released into the air. Finally, the handling and transportation of coal also lead to excessive emissions of air pollutants.5
Mitigation Strategies and Sustainable Mining
The mining industry is establishing a solid framework to promote sustainable and eco-friendly procedures. Newer technologies like green energy sources, adequate air and water treatment methods, and advanced equipment for reprocessing tailing wastes are proving cost-effective in minimizing environmental impacts.
A robust, forward-thinking governance strategy that invests in these technologies as a core business pillar is the blueprint for a sustainable mining industry in the future.6
Digitalizing mines
Mine digitization significantly improves productivity and efficiency while reducing emissions and pollutant releases. With advanced analytics, mines can make data-driven decisions, identify inefficiencies, pollutant sources, and leakages, and implement targeted improvements.
Digitized mines use sensors and Internet of Things (IoT) devices to gather extensive data from various sources. This data is processed using artificial intelligence (AI) and machine learning algorithms to extract valuable insights, contributing to cost savings and sustainability. Automation in mines reduces labor costs, energy consumption, and waste generation. Optimized resource utilization ensures minimal environmental impact and promotes sustainable mining practices.7
Green energy sources and mine electrification
The advancement toward green energy sources will also significantly help promote environmental sustainability in mining industries across the globe. The mining industry has led to increased levels of CO2 emissions in the atmosphere. Transitioning to low-carbon or decarbonized electricity for powering processes, equipment, and power generation is crucial to reducing the industry's carbon footprint. Currently, efforts are primarily focused on electrifying mine equipment. For instance, diesel and gas-powered hauling trucks are now being replaced with electric trucks.
The Borden mine in Ontario, Canada, demonstrates that electrification is feasible without compromising performance. Newmont has converted its entire underground truck fleet from diesel-powered to battery-powered at the Borden mine. As a result of this change, a significant reduction in CO2 emissions has been recorded, proving the effectiveness of this strategy.8
Waste and tailing management
Globally, approximately 100 billion tons of waste, consisting of rocks and tailings, are generated annually by mining. Consequently, companies are developing effective strategies for efficient waste and tailings management.
Titanium mine with tailing ponds filled with technical fluids used in ore enrichment. Image Credit: mykhailo pavlenko/Shutterstock.com
Modern reclamation projects focusing on gold tailing are essential as they provide crucial raw materials and effectively reduce the total waste produced by mining. This results in a less toxic, more stable footprint, freeing up large land areas for productive use.
A classic example of waste management and utilization is arguably experienced in the production of aluminum, more specifically, bauxite mining.
Large quantities of bauxite residues are generated during aluminum extraction from bauxite ores. Microorganisms play an essential role in the bioremediation of pollutants by breaking them down into less toxic forms that are organic and useful to the environment.
Bioremediation, a potential technique employing microorganisms, alleviates the pollution problem since it involves microorganisms' adsorption, accumulation, degradation, and utilization of pollutants as nutrient sources. Managing bauxite mining sustainably and recycling metals from waste is important.9
Sustainable mining platform
Mining companies have also come to appreciate the fact that sustainable mining pays. A prominent example is the Brazilian company Gerdau, famous for mining iron and steel. Gerdau strategically plans to invest approximately $664.5 million to establish a new sustainable mining platform for Minas Gerais. This investment will be fully implemented by 2026 to support sustainable iron mining.
Gerdau’s chief executive officer, Gustavo Werneck, said: “With this new commitment, Gerdau solidifies its responsibility to the social and economic progression of Minas Gerais, restart the bonds with the Minas Gerais public, with the creation of over five thousand direct jobs during the construction of the new investments in the state.”10
An Overview of the Different Rehabilitation Efforts Adopted by Mining Experts
Mining researchers have also focused on rehabilitation processes that seek to reverse lost resources as waste in the mining process. It is the most essential process of restoring the affected land through a mining project, such as replanting trees and disposing of the wastes once the project is over. The re-cultivation process of the mining site needs to be planned adequately to ensure it is successful.
The United Nations has provided a vision of the ten-year plan for ecosystem restoration from 2021 to 2030 to achieve large-scale conservation of the damaged ecosystems.11
Land restoration
Restoring landscapes affected by mining activities is a major interest in world environmental policy and has become integral in global environmental management policies.
Although the process is complex and involves studying geological, hydrological, soil, and vegetative conditions, integrating modern technologies is expected to make it more cost-effective and efficient.
Water treatment methods
Researchers have also prioritized water treatment methods. Various strategies have been devised for treating water affected by acid mine drainage. Adsorption treatment using zeolites, fly ash, biochar, activated carbon, clay-based minerals, and biomass-based adsorbents has proven effective for water treatment and heavy metal removal.
However, membrane separation processes like nanofiltration, reverse osmosis, and hybrid systems are often more effective than adsorption. Biological processes also show a wide range of performance due to the selectivity of different microorganisms. These methods have successfully treated water, removed heavy metals, significantly reduced pollution, and maintained biological diversity in various environments.12
Carbon capture and storage solutions
Although various mitigation and rehabilitation techniques are being researched, advanced carbon capture and storage methods could help the mining industry decarbonize. Some experts suggest emerging technologies may help miners transition to carbon-negative operations.
Conclusion
While the mining sector is necessary for supplying essential raw materials for various modern technologies, it poses significant environmental challenges.
Land degradation, water and air pollution, and the disruption of ecosystems are critical concerns that necessitate adopting sustainable practices.
The integration of advanced technologies like IoT and AI, along with green energy sources and efficient waste management, offers promising solutions for minimizing the environmental impact of mining.
Ensuring robust global policies and financial support for these innovations is crucial for achieving sustainable mineral extraction, vital for human survival and environmental preservation.
References and Further Reading
1. International Energy Forum (2024). How to make mining more sustainable? (Online). Available at: https://www.ief.org/news/how-to-make-mining-more-sustainable [Accessed on June 01, 2024].
2. Sahu, H, et. al. (2011). Land Degradation due to Mining in India and its Mitigation Measures. Proceedings of Second International Conference on Environmental Science and Technology. Singapore. Available at: https://www.researchgate.net/publication/260405156_Land_Degradation_due_to_Mining_in_India_and_its_Mitigation_Measures
3. Pecina, V. et al. (2023). The impacts of mining on soil pollution with metal(loid)s in resource-rich Mongolia. Sci Rep 13, 2763. Available at: https://doi.org/10.1038/s41598-023-29370-w
4. Mining Safety (2024). What To Do About Water Pollution in the Mining Industry? (Online). Available at: https://www.miningsafety.co.za/what-to-do-about-water-pollution-in-the-mining-industry/ [Accessed on: June 02, 2024].
5. Chu, Y. et. al. (2023). Air pollution and mortality impacts of coal mining: Evidence from coalmine accidents in China. Journal of Environmental Economics and Management, 121, 102846. Available at: https://doi.org/10.1016/j.jeem.2023.102846
6. Pan African Resources (2024). A Blueprint for Sustainable Mining. (Online). Available at: https://www.panafricanresources.com/sustainable-mining/ [Accessed on: June 03, 2024].
7. Groundhog Mine Digitization & Automation (2024). How Mine Digitization and Automation is Increasing Productivity and Safety in Mining? (Online). Available at: https://groundhogapps.com/mine-digitization-increasing-productivity/ [Accessed on: June 03, 2024].
8. Godemel, F. (2023). How will electrification reduce mining’s large carbon footprint? (Online). Available at: https://blog.se.com/industry/2023/09/14/how-will-electrification-reduce-minings-large-carbon-footprint/ [Accessed on: June 04, 2024].
9. Pradhan, G. et. al. (2023). Bauxite Mining Waste Pollution and Its Sustainable Management through Bioremediation. Geomicrobiology Journal, 41(4), 335–344. Available at: https://doi.org/10.1080/01490451.2023.2235353
10. Mining Technology (2023). Gerdau to spend $664.5m on sustainable mining in Brazil. (Online). Available at: https://www.mining-technology.com/news/gerdau-sustainable-mining-brazil/ [Accessed on: June 05, 2024].
11. Wang, H et. al. (2022). Ecological Management and Land Rehabilitation in Mining Areas from the Perspective of Actor-Network Theory—A Case Study of Lizuizi Coal Mine in China. Land. 11(12):2128. Available at: https://doi.org/10.3390/land11122128
12.Ighalo, J. et. al. (2022). A review of treatment technologies for the mitigation of the toxic environmental effects of acid mine drainage (AMD). Process Safety and Environmental Protection, 157, 37-58. Available at: https://doi.org/10.1016/j.psep.2021.11.008
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