How does longwall mining remove minerals from a seam?

Longwall mining is a highly efficient underground extraction method used for flat-lying deposits like coal, salt, and potash. The process involves removing minerals from a large rectangular block or panel, typically 100 to 300 meters wide.12

In modern mechanized operations, the extraction is performed by a continuous mining machine known as a shearer or a plow. These machines move back and forth along the longwall face, cutting a slice of the mineral from the seam. The extracted material is then loaded onto an armored conveyor that runs along the face to transport the product out of the panel.132

To ensure safety, the area is protected by self-advancing hydraulic supports, or shields, which provide a steel canopy for workers and equipment. As the machine advances and the mineral is removed, these supports are shifted forward, allowing the roof behind the canopy to cave in. In harder rock formations where machines cannot cut the material, the seam is instead removed through drilling and blasting.12