The song was called "Sixteen Tons" and the final enduring lines captured the pathos of the miners' continuing struggle:
"You load sixteen tons, what do you get?
"Another day older and deeper in debt.
"St. Peter don't you call me "cause I can't go.
"I owe my soul to the company store."
Miners lived in company towns and purchased food and other goods from company stores. These stores charged usurious rates and miners were forever behind, striving to catch up, hence the line from "Sixteen Tons" about miners' souls being owed to the company store.
There was one period during what the "Hell no!" Republicans, Tea Baggers, Milton Friedman free marketers and Ayn Rand Objectivists regard as the Dark Age, the New Deal of Franklin Delano Roosevelt, when a spirit of cooperation existed between United Mine Workers President John L. Lewis and the nation's chief executive where safety regulations were put in place.
Meanwhile Lewis worked hard to obtain living wages for his workers, battling tenaciously against the wealthy, entrenched mining interests.