In construction the unskilled people that we hire are the Laborers. They sweep up, they shovel dirt, they carry things, they clean the site. In union work they are paid the least, but they are in the same trade union as the operating engineers and they are training to eventually become OE's themselves. OE's operate the cranes and the earth moving machines like the front end loaders, the bulldozers, etc., literally the machines that have automated the laborers work over the years.
My grandfather was an old school UAW worker back in the 1960s and 1970s and once he was telling stories about how the more senior guys get to choose the jobs they wanted. He started to talk about some guys who had been around so long they got to be "sweepers". Being a young and naive teenager at the time I asked him "you mean like they go around working on whatever problem needs the most attention". And he said "no, they go around with a broom sweeping things".