Mining

 https://fraser.stlouisfed.org/files/docs/publications/bls/bls_0454_1927.pdf

https://fraser.stlouisfed.org/files/docs/publications/bls/bls_1461_1965.pdf

https://en.wikipedia.org/wiki/History_of_coal_miners

https://en.wikipedia.org/wiki/History_of_coal_mining_in_the_United_States

https://ehistory.osu.edu/exhibitions/gildedage/content/MinersStory

https://www.iup.edu/library/departments/archives/coal/people-lives-stories/a-womans-day-work-and-worry.html

https://www.nps.gov/articles/000/introduction-to-the-west-virginia-mine-wars.htm

https://www.sciencedirect.com/science/article/abs/pii/S0014498317302437