By a calculation approach it was determined that in cleaning conditions of steel pipes, for example, 56×3 и 76×3 mm, at discharge in liquid, and all the more in sediments layer 5-8 mm thick, pressure amplitude in discharge filament is several times higher the breaking point on compression of solid sediments (σ >40 MPа). The deciding role in the process of sediments destruction belongs to the pressure pulse in the channel of primary discharge inside the sediments layer. There are three pipe sections typical for electrohydraulic refinement and two fissuring areas before the destruction front. The reasons of regrinding initiation, sediments cracks, primary and opposed destruction front rising and propagation were examined.