why is coal found in layers
EXPERT ANSWER. Coal if formed when dead animals and plants got buried inside the layer of Earth. The layers increase form time to time and more dead plants and animals get buried in the layers.Therefore, coal is found in layers.For example, let us consider the layers of sandwich, on the first bread we apply the toppings and cover it another slice. Then some more topping is added to second slice and is covered by third slide.XPERT ANSWER. Coal if formed when dead animals and plants got buried inside the layer of Earth. The layers increase form time to time and more dead plants and animals get buried in the layers.
Mining is classified by the method needed to reach the coal seam. When the coal is found close to the Earth's crust and taking away the overlying layers of material is not too expensive, surface mining is used to remove the top layers of materials and expose the coal.If coal is found in layers far from the surface, underground mining is the preferred technique.Vertical or slanted holes (shafts) are cut down to the mining area underground for ventilation for the workers and for transporting the miners, equipment, and coal.ining is classified by the method needed to reach the coal seam. When the coal is found close to the Earth's crust and taking away the overlying layers of material is not too expensive, surface mining is used to remove the top layers of materials and expose the coal.