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.
Coal mining in Wyoming. Coal mine in Wyoming. Coal mining in Wyoming has long been a significant part of the state's economy. Wyoming has been the largest producer of coal in the United States since 1988. In 2013, there were 17 active coal mines in Wyoming, which produced 388 million short tons, 39 percent of all the coal mined in the US, and more than three times the production of second-place West Virginia.