Post-ore faults in the Sadonskoye deposit are accompanied by white and black clays. In the specialized literature, a paste or vein clay (gouge) is a soft, clay-like material that occurs as a rim between the vein and side rocks. The paste is usually formed by crushing and abrasion of ore, or side rock, or both together. Previous researchers considered the black clay of the Sadonskoye deposit to be clay shales captured by the fault (Domarev, Skakovsky). As a result of geological, petrographic and mineralogical studies, black clay appears as ground rock, crushed by the western fault, the source material for which was the side rocks of the ore body and the ore body itself.