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.
This estimate of about 60,000 jobs in operations & maintenance in all U.S. coal-fired power plants seems reasonable, as 2006 U.S. Department of Labor data tells us that installation, maintenance, repair, and production occupations employed 160,980 people at all power plants in the U.S. in 2006.