The concept of securitization is generally associated with the Copenhagen school of security studies, which is generally taken to include Ole WÃ¦ver, Barry Buzan, and a range of other, more loosely associated, researchers.
Average annual number of employed coal miners in the United States, 1890-2014. US employment in coal mining peaked in 1923, when there were 863,000 coal miners. Since then, mechanization has greatly improved productivity in coal mining, so that employment has declined at the same time coal production increased. The average number of coal mining employees declined to 65,400 in 2015.
The United States has about a 235-year supply of coal, if it continues using coal at the same rate at which it uses coal today. Montana is the state with the most coal reserves (119 billion tons). But Wyoming is the top coal-producing stateâit produced over 400 million tons in 2012. Texas is the top coal-consuming state. It uses about 100 million tons each year. The average coal miner is 45 years old and has 16 years of experience. Coal ash, a byproduct of coal combustion, is used as filler for tennis rackets, golf balls, and linoleum. U.S. coal deposits contain more energy than that of all the worldâs conventional oil reserves.