Longwall mining is a method used to extract coal from underground mines. It involves cutting a long, horizontal slice of coal from a seam, typically several hundred meters long. Specialized machinery, including a shearer, moves along the coal face, removing the coal and transporting it to the surface. As the coal is extracted, the roof of the mine is supported by hydraulic jacks, known as roof supports. Once the coal is removed, these supports are gradually retracted, allowing the roof to collapse in a controlled manner. This technique is efficient and can yield large amounts of coal while minimizing surface disruption.