Auger mining is a surface mining technique used to recover additional coal from a seam located behind a highwall produced either by excavation or previously mined areas. An auger is a drilling device that consists of a rotating helical screw blade called a “flighting” that is used to move granular material, such as coal, from the highwall back to the entrance of the mine.

The auger is mounted on a rig that is capable of moving horizontally along the highwall, and it is equipped with a cutting head that bores into the coal seam as the auger rotates. As the auger advances, the coal is broken up and carried back to the entrance of the mine by the flighting.

Auger mining is typically used to extract coal from seams that are too thin or steep to be mined using traditional surface mining techniques, or when the coal seam is located in an area that is not suitable for surface mining due to environmental or logistical constraints. It is a relatively low-cost and low-risk mining method, and it can be used to recover coal that would otherwise be left behind during traditional surface mining operations. However, auger mining can be less efficient than other surface mining methods, as it leaves much of the coal in place and can result in lower recovery rates