Energy Resources Questions Long
Coal formation is a complex geological process that takes millions of years to occur. It begins with the accumulation of organic matter, mainly plant material, in swampy environments. Over time, this organic matter undergoes a series of transformations, leading to the formation of coal.
The process of coal formation starts with the deposition of plant material in a swampy environment. As plants die, their remains settle at the bottom of the swamp, forming a layer of organic material known as peat. Peat is composed of partially decomposed plant matter, and it contains a high amount of carbon.
Over time, as more layers of plant material accumulate on top of the peat, the weight and pressure from the overlying sediments compress the peat. This compression causes the water content to be squeezed out, and the peat gradually transforms into a soft, brownish material called lignite. Lignite has a higher carbon content than peat and is considered the lowest rank of coal.
As the process continues, the lignite undergoes further compaction and heating, resulting in the formation of bituminous coal. Bituminous coal is black and shiny, with a higher carbon content than lignite. It is the most commonly mined coal worldwide.
If the process of coal formation continues, with increased heat and pressure, the bituminous coal can transform into anthracite coal. Anthracite coal is the highest rank of coal and has the highest carbon content. It is hard, black, and lustrous.
The extraction of coal involves various methods depending on the depth and location of the coal seam. The two primary methods of coal extraction are surface mining and underground mining.
Surface mining, also known as strip mining, is used when coal seams are close to the surface. In this method, large machinery, such as draglines, shovels, or bulldozers, remove the overlying soil and rock layers to expose the coal seam. The coal is then extracted using trucks or conveyor belts.
Underground mining is employed when coal seams are deeper underground. There are two main types of underground mining: room and pillar mining and longwall mining. In room and pillar mining, tunnels are excavated into the coal seam, leaving pillars of coal to support the roof. The coal is then extracted by removing the pillars. In longwall mining, a shearing machine called a longwall miner is used to extract coal in a continuous process. The machine moves along the coal seam, cutting and removing the coal as it progresses.
After extraction, the coal undergoes processing to remove impurities and improve its quality. This process, known as coal preparation or coal washing, involves crushing the coal into smaller sizes and separating it from rocks, minerals, and other impurities. The cleaned coal is then transported to power plants, industries, or used for various other purposes.
In summary, coal formation is a gradual process that involves the accumulation and transformation of plant material over millions of years. The extraction of coal involves surface mining or underground mining methods, depending on the depth and location of the coal seam. After extraction, the coal is processed to remove impurities before being used as a valuable energy resource.