1. n. [Drilling Fluids]

A clay-based water mud that used tannates (from tannic acid) as clay deflocculant and mined lignite for fluid-loss control, usually with lime. The tannates were usually quebracho, which is red at high pH. Red muds were used extensively in the 1940s and 1950s.

Alternate Form: quebracho

See: deflocculant,  lime mud,  pH,  starch,  tannin