Longwall mining is a method used to extract coal from underground mines. In this technique, a long wall of coal is mined in a single slice, typically around 1 to 2 meters thick. Specialized equipment, including a shearer, cuts the coal from the face, while hydraulic supports hold up the roof of the mine to prevent collapses. After the coal is extracted, the area behind the supports is allowed to collapse, which helps to minimize surface subsidence. This method is efficient and can produce large amounts of coal, making it a popular choice in many coal-producing regions around the world.