On the other side of the Atlantic, Archie Green wrote extensively in Only A Miner about a certain class of American industrial folk songs. Unlike Lloyd, however, Green did not invent his sources. I don't doubt that 'industrial songs' were written in nineteenth-century Britain. If Lloyd wanted to write about them, he should have dug some up. There are any number of reasons why such songs might have been less likely to have gone into tradition than songs of love and loss, murder ballads, etc., but inventing sources shouldn't be necessary if the raw material is really out there waiting to be found.