3 Coal Mining Methods
Open pit mining is used for approximately 40% of coal production. The used machinery equipment can be used to extract coal. Mining coal is less expensive if it is near the surface. Once the carbon is mined, the topsoil is replaced and native trees and vegetation are planted to restore the original condition. There are three different types of surface mining: contour, open pit, and mountaintop removal mining.
1- contour mining: Contour Mining is most commonly used in areas that have steep or undulating terrain. It involves digging the earth above the coal line, or coal seam, along the contours of the mountainous terrain. This method can be dangerous because it can cause landslides and erosion problems.
2- opencast mining: Open pit mining generally occurs on flat ground. The earth is excavated in long cuts or strips until the coal seam is exposed. Once the strip has been drilled and blasted and all the coal has been removed, a new strip is created right next to it and the process continues.
3- Mountaintop removal mining: Mountaintop removal mining involves the use of a combination of contour mining and open pit mining. The tops of the mountains are removed to expose the coal below and the coal is mined.
Underground mining methods
If the coal seams are too deep underground, then deep underground mining is necessary. Deep underground mining methods include continuous, longwall, blast, pullout, and shortwall mining.
Oh Continuous Mining: A machine having a large rotating steel drum with tungsten carbide teeth scrapes the coal from the seam. Conveyors are used to transport mined coal. About 5 tons of coal can be mined per minute. It represents about 45% of underground coal production.
Oh longwall mining: A sophisticated machine that has a rotating drum that mechanically moves back and forth along the seam. The loose coal falls into the tray line that carries the coal to the conveyor belt. It represents about 50% of coal production.
Oh Burst: An older mining method that uses dynamite and explosives to break the coal seam. It represents less than 5% of coal production.
Oh mining in retirement: One of the most dangerous methods of coal extraction. The pillars are used to support the roof of the mine while coal is mined. The pillars collapse as the miners retreat.
Oh short pit mining: Similar to longwall mining. It uses a continuous mining machine with movable roof supports. The machine cuts coal panels about 200 feet wide and half a mile long.