Last year marked the 100th anniversary of the worst mining disaster in US mining history. An explosion at the Monongah coal mine in West Virginia officially killed 361 men and boys but the true figure will never be known. Some put it as high as 950. Most who died were immigrant workers. There are scores of web sites on the subject but I've added this link to the mine entry as it contains some interesting archive photos and highlights the subject of boys working down the mines. Dec. 1907 was a bad month for the US coal mining industry but a tragic one for the miners and their families.
http://einhornpress.com/Monongah.aspx
The past is a foreign country: they do things differently there.