Wiktionary
bluecaps
n. (plural of bluecap English)
Usage examples of "bluecaps".
Once a fortnight I go down the mine and leave payment for the knockers and the bluecaps in a solitary corner, keeping a bit back myself for cartage.
The underground creeping got to it, not long before the knockers and bluecaps moved in—so they say—and the mill subsided, but that was before we came here.