Mining operations often rely on groundwater abstraction for various purposes and practises, including dewatering of the regional water level at underground and opencast operations, dust suppression, and ore processing. The process typically involves drilling wells or boreholes to extract groundwater from aquifers located beneath the earth's surface. This extraction can lead to a range of environmental consequences, which is summarized below:
- Lowering of the Water Table
One of the most immediate and direct impacts of groundwater abstraction from mines is the lowering of the water table. When water is pumped from underground aquifers, it reduces the groundwater level in the vicinity of the mine. This can result in:
- Drying of Springs and Wetlands: The reduced flow of groundwater to surface water bodies such as springs and wetlands, can lead to significant reduction in water levels or even dry completely. This can harm the unique ecosystems and biodiversity they support.
- Negative Impact on Riparian Vegetation: Lowered water tables can affect riparian vegetation along rivers and streams, disrupting habitat for wildlife and altering the ecology of these areas.
- Subsidence: Excessive groundwater abstraction can cause land subsidence, where the ground sinks due to the compaction of sediments. This can result in damage to infrastructure, including roads and buildings. In certain geological formations, the formation of sinkholes can also be aggravated.
Groundwater abstraction from mines can increase the risk of groundwater contamination. Mining activities often involve the use of chemicals and the release of potentially harmful substances into the environment for instance, explosives. These contaminants can infiltrate the groundwater system, posing risks to both human health and the environment. Scientists and especially, Geohydrologists play a crucial role in monitoring and mitigating these contamination risks through groundwater quality assessments and remediation efforts.
- Impact on Surface Water Bodies
The lowering in groundwater levels due to abstraction can also have indirect impacts on surface water bodies, such as rivers and lakes. Lower groundwater levels can reduce the baseflow that sustain these water bodies, potentially leading to decreased flow rates, altered water temperatures, and impaired aquatic ecosystems.
To minimize the environmental impact of groundwater abstraction from mines, it is essential to implement effective mitigation strategies:
- Sustainable Groundwater Management: Implement sustainable groundwater management practices that prioritize maintaining ecological flows and preventing excessive groundwater drawdown.
- Environmental Impact Assessments: Conduct comprehensive environmental impact assessments before mining operations start, to identify potential impacts and plan mitigation measures accordingly.
- Groundwater Monitoring: Continuously monitor groundwater levels, quality, and potential contamination sources to detect issues early and take corrective actions.
- Water Recycling and Treatment: Invest in water recycling and treatment technologies to minimize the use of fresh groundwater and reduce contamination risks.
- Ecosystem Restoration: Implement restoration projects to rehabilitate areas affected by mining activities, including wetlands and riparian zones.
Groundwater abstraction from mines has far-reaching environmental consequences that geohydrologists must study, manage, and mitigate. By understanding the impacts, monitoring groundwater systems, and implementing sustainable practices, we can strike a balance between mining activities and environmental preservation, ensuring the long-term health of our ecosystems and communities. Collaborative efforts from industry, regulators, and environmental scientists are essential to achieve this goal.
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• Department of Water and Sanitation, 1998. General Authorizations in terms of the National Water Act.
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