Better hope they done have one set of 50mm bolts which are mild steel, and another set that are hardened high tensive steel that aren't clearly marked and the same length!
Or you're going to have quite an adventure when you go to do your thing and a random selection of bolt heads come pinging off at you at mach 5.
Anyone who has worked in a job classified 'unskilled' generally doesn't need a pejorative to feel unloved. It's the nature of the game.
Digging ditches generally sucks, same as I imagine being a striker, but most anyone can do it (until their body gives out, anyway, which in some cases is 'immediately').
HDPE is also what Nalgenes and the like are made of (or used to be anyway), and is very popular for storing chemicals as well. It is very nearly completely inert.