noun
Etymology: pug (III)
: a machine consisting of a shaft armed with blades revolving in a drum or trough and used for mixing or tempering a plastic substance into a desired consistency
brick-clay … might need sieving, weathering, and mincing in the pug mill before it could be worked — Katharine S. Woods
clay … and mixed by hand, foot, or pug mill to the right consistency for throwing — Bernard Leach
rubber compound … thinned down with naphtha to suitable consistency in a pug mill — H.P.Stevens & Clayton Beadle
especially : cement mixer