System and method of forming an underground slurry wall

A method of forming an underground slurry wall having the steps of: (a) providing a trencher having a trenching arm assembly with a cutting tooth track; (b) providing a dispensing tube proximate the cutting tooth track; (c) rotating the cutting tooth track; (d) extending the cutting tooth track below the outside surface, to, in turn, agitate the soil therebelow to a predetermined depth; (d) translating the trenching arm assembly across the outside surface so as to form an underground wall of agitated soil; (e) dispensing a clay-like material proximate the cutting tooth track; and (f) utilizing the cutting tooth track to mix the clay-like material into the soil while the cutting tooth track is rotating and translating, to, in turn, mix the clay-like material into the agitated soil. Systems are likewise disclosed.