What types of coal deposits are accessed using the surface mining techniques of strip mining and mountaintop removal?

Strip mining is a surface mining technique in which large strips of earth and rock are removed to expose the underlying coal deposit. This method is used when the coal deposit lies relatively close to the surface, making it more efficient than accessing the coal through underground mining. The process involves removing overburden (rock, soil, and vegetation) and extracting the coal.

Mountaintop removal is another surface mining technique, where the tops of mountains are removed to expose coal seams. This method is usually employed in areas with steep terrain, where coal deposits are found in narrow seams running horizontally along the mountain sides. The mining process involves removing large amounts of rock and soil, which is then dumped into nearby valleys, potentially causing environmental damage.

Both strip mining and mountaintop removal techniques are used to extract coal deposits that lie near the surface. Specifically, these methods are applied to access the following types of coal deposits: 1. Lignite deposits: Lignite is a soft, brown coal with a high water content and low carbon content, making it less energy-dense than other types of coal. It is typically found close to the surface, making it suitable for surface mining techniques. 2. Bituminous coal deposits: Bituminous coal is a dense, hard black coal with higher carbon content than lignite. It releases more energy when burned and is used primarily for electricity generation and heating purposes. Bituminous coal deposits can sometimes be found near the surface and accessed through strip mining or mountaintop removal. In summary, strip mining and mountaintop removal techniques are used to access coal deposits, such as lignite and bituminous coal, that are located near the Earth's surface.