Gypsum
Gypsum is derived from the Greek word gypsos which means plaster (Gypsum Meanings, Powers, and History). Gypsum is composed of oxygen, calcium, sulfur, and water (Properties and Uses of Gypsum). The chemical formula for gypsum is CaSO4•2H2O (Properties and Uses of Gypsum). Gypsum is the most common sulfate mineral, and also the most common evaporate (Gypsum Meanings, Powers, and History). Evaporation of water …show more content…
Coal can be mined in two different ways, either by surface mining or underground mining methods (Coal and the Environment). Surface mining is done when the coal is less than 200 m below the Earth’s surface, while underground mining is done when the coal is more than 200 m below the surface of the Earth (Coal and its Uses). Underground mining accounts for approximately 60% of the world’s coal production (Coal and the Environment). Some of these underground mines can go as deep as 1000 m below the Earth’s surface (Coal and its Uses). While some large surface mines can cover many squares kilometers in area and have the advantage of lower mining costs in comparison to underground mining (Coal and the Environment). Figures 7 and 8 below display a surface coal mine and an underground coal mine respectively. Figure 7. Surface coal mine Figure 8. Inside of an underground coal mine
After coal is mined it needs to be processed, first, the coal is washed or cleaned to remove contaminants and impurities, this is usually done a preparation plant (Coal and its Uses). By removing the impurities from coal, it burns significantly cleaner and is better for the environment (Coal and its Uses). The coal is combusted, releasing heat as energy, which is used to boil water and produce steam which operates a steam turbine and generator which produces electricity (Coal and its Uses). In Figure 9 below is a coal power plant that is located in Germany. Figure 9. German coal power plant