But there's more in Sandburg:

SHOVELLIN' IRON ORE

Something happened the other day, that never happened before.
A man tried to get me to shovel iron ore.
Says I, "Old man, now what will you pay?"
Says he, "Two bits a ton."
Says I, "Old man, go diddle yourself,
I'd rather bum."

Notes: "I got a snootful of it and I'll never go back," a fellow coal shoveler told me once in Omaha. He was speaking of iron ore, heavier, dirtier, more infiltrating than coal dust...Those who sing this usually hook it up with "We Are Four Bums."

from Carl Sandburg, The American Songbag (1927), page 182