Two major coal mining methods is underground coal mine and surface mine.
Underground Coal Mine
There are two methods of underground Coal mine, room-and-pillar mine and longwall mine. Room and pillar mining method is done by cutting coal mine area then conveys it to a waiting shuttle car which transports it to the conveyor belt to be moved to the surface and no explosion is needed. After reach a specified distance, the continuous miner is backed out and roof bolts are put in place. The process is repeated until the coal seam is mined.
Longwall method involves pulling a cutting machine of the coal seam. This machine has a revolving cylinder with tungsten bits that shear off the coal. Longwall mining involves making careful planning to ensure there is geological support before starting mining activities. Depth of coal surface varies in depth of 300 – 1000 feet. The mine roof is supported by large steel supports, attached to the longwall machine. As the machine moves forward, the roof supports are advanced and The coal falls into a conveyor system which carries it out of the mine to surface. Nearly 75 percent of the coal can be removed using this method. The remaining 25 percent of underground production is produced by conventional mining which uses explosives to break up the coal for removal.
Surface mine
Surface mine is also called a Open Mine, this method only has economic value when the coal near to the surface. To do this, company must gather an information about climate, soil composition, wildlife and government regulation of surface mine. With open mine method, about 90% of coal could be taken. Open mine involves lot of tools including dragline, hydraulic shovel, excavator, treadmill and mine trucks to transport the coal to the surface. The coal and soil separated with explosive, then the materials transported to the surface through a pulley puller or with shovels and trucks. Once the coal is removed, the land is returned to the desired contour and Native vegetation or trees are planted.
Coal Processing
The coal processing depending on the content and purpose. This coal may only need a simple process, or may require complex manufacturing processes to get specific coal quality. To separate coal and other material, the raw coal separated into fractions of various sizes then this raw material released into tank containing liquid with specific gravity, lighter materials will float and can be separated, stone and other materials which are heavier and will sink discarded as waste.
Smaller fraction is processed according to differences in density as the centrifuge. Centrifuge is a machine that reproduces an old very quickly, so that separates solid and liquid inside the container. Alternative methods using different surface content of coal and waste. In flotation, the carbon particles are separated in the bubbles produced by air blown into the immersion of water containing chemical reagents. Recent technology developments helps improve good quality of coal.
Underground Coal Mine
There are two methods of underground Coal mine, room-and-pillar mine and longwall mine. Room and pillar mining method is done by cutting coal mine area then conveys it to a waiting shuttle car which transports it to the conveyor belt to be moved to the surface and no explosion is needed. After reach a specified distance, the continuous miner is backed out and roof bolts are put in place. The process is repeated until the coal seam is mined.
Longwall method involves pulling a cutting machine of the coal seam. This machine has a revolving cylinder with tungsten bits that shear off the coal. Longwall mining involves making careful planning to ensure there is geological support before starting mining activities. Depth of coal surface varies in depth of 300 – 1000 feet. The mine roof is supported by large steel supports, attached to the longwall machine. As the machine moves forward, the roof supports are advanced and The coal falls into a conveyor system which carries it out of the mine to surface. Nearly 75 percent of the coal can be removed using this method. The remaining 25 percent of underground production is produced by conventional mining which uses explosives to break up the coal for removal.
Surface mine
Surface mine is also called a Open Mine, this method only has economic value when the coal near to the surface. To do this, company must gather an information about climate, soil composition, wildlife and government regulation of surface mine. With open mine method, about 90% of coal could be taken. Open mine involves lot of tools including dragline, hydraulic shovel, excavator, treadmill and mine trucks to transport the coal to the surface. The coal and soil separated with explosive, then the materials transported to the surface through a pulley puller or with shovels and trucks. Once the coal is removed, the land is returned to the desired contour and Native vegetation or trees are planted.
Coal Processing
The coal processing depending on the content and purpose. This coal may only need a simple process, or may require complex manufacturing processes to get specific coal quality. To separate coal and other material, the raw coal separated into fractions of various sizes then this raw material released into tank containing liquid with specific gravity, lighter materials will float and can be separated, stone and other materials which are heavier and will sink discarded as waste.
Smaller fraction is processed according to differences in density as the centrifuge. Centrifuge is a machine that reproduces an old very quickly, so that separates solid and liquid inside the container. Alternative methods using different surface content of coal and waste. In flotation, the carbon particles are separated in the bubbles produced by air blown into the immersion of water containing chemical reagents. Recent technology developments helps improve good quality of coal.
