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.
United States. Th e United States has more coal that can be mined than the rest of the world has oil that can be pumped from the ground. We have enough to last more than 250 years! Currently, coal is mined in 25 of the 50 states. Fossil Energy Study Guide: Coal key