Coal mining.I come from a coal mining family Both of my Grandfathers were coal miners in WV.
The Darr Mine, at Van Meter, was the site of one of the worst coal mining disasters in the United States. On December 19, 1907 a gas and dust explosion killed 239 coal miners in the dark tunnels of the Darr Mine. An inquiry into the disaster afterwards concluded, as was usually the case in that period of Pennsylvania coal mining, that the Pittsburgh Coal Company was not at fault.
Canary Bird in the Coal Mine ~~~ One of coal mining’s earliest systems for warning of the presence of methane gas, the canary in the coal mine, though low-tech, was extremely effective and rather easy to read: if the bird died, miners had to get out of the shaft.