Merle Travis, "Sixteen Tons". It's Travis's song, although the most widely known versions of this are Tennessee Ernie Ford's version, which made it famous (and is one of the best uses of snapping fingers as a musical instrument), and Eric Burdon's soulful rock version, best known for being the opening song of Joe vs. the Volcano. In any case, it's Joe vs. the Volcano which brought the song to mind; an excellent, excellent movie (and in my opinion far and away the best Tom Hanks / Meg Ryan movie). Which came out thirty years ago, if I ever want to remind myself of how increasingly old I am, since I saw it almost as soon as it hit VHS.