The two most common methods of coal mining include surface and underground mining. The geology of the coal deposit is the primary factor that determines the preferred method. As of 2015, surface mining accounts for 67 percent of coal production in the United States.
The surface mining method typically recovers more than 90 percent of coal from coal seams, but it’s economically viable only when the seams are close to the surface. There are two ways of going about underground mining: room-and-pillar mining and longwall mining. The former involves cutting a network of spaces through the coal seam and leaving pillar-like sections of coal to support the roof of the mine. The latter involves using mechanical shearers to fully extract the coal from a specific section of the coal seam.