Britannica
Sources used in this answer
How does longwall mining remove coal from a large underground block?
Created from Britannica articles
using AI.
AI can make mistakes, so verify using Britannica articles.
coal mining
Schematic diagram of an underground coal mine, showing surface facilities, access shafts, and room-and-pillar and longwall mining methods.
Longwall mining extracts coal by removing large blocks, typically 100 to 300 meters wide and 1,000 to 3,000 meters long, in sequential slices.1
Mechanized Extraction
In modern operations, the process is highly mechanized to create a continuous mining system:
- Cutting and Loading: Shearers or plows move along the coal face, cutting slices of coal and loading them onto a face conveyor.12
- Roof Support: Self-advancing, hydraulic steel shields protect the area. These supports are lowered, advanced, and reset against the roof as the mining equipment moves forward, providing a safe, prop-free workspace.13
- Cycle: The cycle of cutting, loading, and advancing the supports and conveyor is repeated until the entire block is extracted.1
Mining Methods
There are two primary approaches to this process:
* Retreating Method: The block is developed to its boundary first, then mined back toward the main haulage tunnel. This is the most common method in the United States.1
* Advancing Method: Development and mining proceed together toward the boundary, a practice more common in Europe.1