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.
In 2015, the productivity capacity of U.S. coal mines decreased for the fourth year in a row to 1,165 MMst, a decline of 6.3% from the 2014 levels. The average number of employees at U.S. coal mines decreased 12.0% to 65,971 employees, the lowest on record since EIA began collecting data in 1978. U.S. coal consumption of 798 MMst in 2015 was 13.1% lower from the 2014 levels. The electric power sector consumed about 92.5% of the total U.S. coal consumption in 2014.