Underground Coal Mining

There are five types of underground coal mining; drift, shaft, room & pillar, continuous, and longwall.

Drift mining is when the mine enters the seam horizontally, following the coal and is possible where coal seams intersect the surface. An advantage of drift mining is that gravity helps pull the coal down but cave ins are a constant threat. http://www.greatmining.com/drift-mining.html

 

Shaft mining is the most common method used in W.V. Elevators provide access to mines which are commonly 1000+ ft below the surface. These mines reach some of the lowest seams of coal but there is always the threat of mine collapse.http://www.uky.edu/KGS/coal/coal_mining.htm

Room & Pillar mining leaves nearly half the coal behind to support the roof. Room and Pillar mining is fast and simple but pillars sometimes squeeze leading to roof collapse, which is a constant danger. http://www.wisegeek.com/what-is-a-room-and-pillar.htm

Continuous Mining is a form of room and pillar mining that uses a machine that has a rotating steel drum with tungsten carbine teeth and can mine 5 tons of coal per minute. These machines are paired with conveyor belts to transport coal to the surface. But as with regular room & pillar mines there is a constant danger of roof collapse. http://www.wisegeek.com/what-is-a-room-and-pillar.htm

Longwall mining or retreat mining is a very efficient method of mining. A huge machine supports the roof with hydraulics as it removes the coal. This removes more coal than room & pillar mining but as soon as the machine is removed the roof falls. http://www.uky.edu/KGS/coal/coal_mining.htm