1 1 gram of SO 2 for every million mL of air (parts per million by mass per volume). 2  Write ppm in terms of cubic meters. 3  There are a million cubic centimeters in a cubic meter (1 cm 3 = (10 -2) 3 m 3 = 10 -6 m 3) so one part per million of SO 2 by volume in air is actually 1 cm 3 SO 2 / 1 m 3 of air. 1 gram of SO 2 for every million grams of air (parts per million by mass); 2  1 mL of SO 2 for every million mL of air (parts per million by volume); 3  1 gram of SO 2 for every million mL of air (parts per million by mass per volume). 4  Write ppm in terms of cubic meters.
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.
Carbon from burning coal reacts with air to form carbon dioxide. When carbon dioxide and other gases, such as those emitted from automobiles, accumulate in the earth's atmosphere, they form a shield that allows the sun's light and heat in, but doesn't let it out. This condition is called the greenhouse effect.here are two ways to remove coal from the ground: surface mining and underground mining. Surface mining is used when a coal seam is relatively close to the surface, usually within 200 feet. The first step in surface mining is to remove and store the soil and rock covering the coal (called the overburden).