Longwall mining

Definition

Longwall mining is a method of underground coal mining that involves the use of a long wall of coal that is mined in a single slice, usually about 1.5 meters thick. This technique allows for the efficient extraction of large volumes of coal while minimizing surface disturbance and maximizing recovery rates, but it can also lead to significant environmental impacts.

5 Must Know Facts For Your Next Test

1. Longwall mining can extract up to 90% of the coal from a seam, making it one of the most efficient coal mining methods available.
2. The process involves a continuous miner that cuts the coal from the seam, which is then transported to the surface on conveyor belts.
3. Once the coal is removed, hydraulic supports are used to hold up the roof of the mine while the longwall face is being mined.
4. This method can cause subsidence above the mined area, leading to cracks in the ground and potential damage to surface structures and ecosystems.
5. Longwall mining operations require careful planning and monitoring to mitigate environmental impacts and ensure worker safety.

Review Questions

• How does longwall mining compare to other underground mining methods in terms of efficiency and environmental impact?
  • Longwall mining is often more efficient than other underground methods like room and pillar mining because it can recover a higher percentage of coal from a seam. However, this increased efficiency comes with significant environmental concerns, particularly related to subsidence and habitat disruption. While room and pillar methods leave more coal in place for structural support, they do not extract as much resource overall. Thus, longwall mining presents a trade-off between maximizing resource extraction and managing ecological effects.
• Discuss the technological advancements in longwall mining and their implications for worker safety and environmental management.
  • Technological advancements in longwall mining, such as automated continuous miners and advanced monitoring systems, have significantly improved both worker safety and environmental management. Automation reduces the number of workers exposed to hazardous conditions underground, while real-time data collection allows for better assessment of ground stability. Additionally, modern hydraulic support systems can be adjusted more effectively to minimize subsidence risks, leading to improved outcomes for both miners and surrounding communities.
• Evaluate the long-term consequences of longwall mining on local ecosystems and community health, considering regulatory frameworks.
  • Long-term consequences of longwall mining can include severe impacts on local ecosystems due to subsidence and water table changes, which affect plant and animal life. Communities may also experience health issues related to dust exposure and contaminated water supplies. Regulatory frameworks play a crucial role in mitigating these effects by enforcing environmental assessments and rehabilitation requirements. However, if regulations are not adequately enforced or updated to reflect technological changes and community needs, the risks associated with longwall mining could exacerbate over time.

Related terms

subsurface mining: A type of mining that involves the extraction of minerals and resources from beneath the earth's surface, typically using tunnels or shafts.

room and pillar mining: An underground mining method where pillars of coal are left standing to support the roof while rooms are mined out.

subsidence: The sinking or settling of the ground surface that can occur as a result of underground mining activities, particularly in longwall mining.