"Got a boss? You need a union." (Steve Earle)

Below is a chart showing coal mining fatalities in the US per 1000 coal miners. In 1930, the United Mine Workers finally gained representation rights for most miners in the US, In 1970, the Mine Safety Act was signed into law. It got through Congress because of a full-court press by the UMWA and their allies in the labor movement--not because the Nixon administration cared particularly. (During WW2, mine safety rules sort of got ignored...)

 

The 1968 spike was the Farmington mine explosion (https://en.wikipedia.org/wiki/Farmington_Mine_disaster); the mine was 12 miles away from Fairmont, WV, but the blast was visible there. 78 miners were trapped in the mine and died. There were 233 other mine fatalities that year...roughly the same as in 1967 and 1969.

From 1900 to 2017, 104,866 miners have been killed in coal mines in the US. Worldwide the death toll is many times than much. As a comparison, about 110,000 coal miners died in the UK from 1900 to 2010. It appears that more than 1,000 mining fatalities per year are still occurring in China...