The article discusses the use of slightly soluble small size anodes as current lead to coke backfill. It is shown that the backfill is able to play the role of a porous electrode with developed surface area. Protective current density on the electrode and anodic potential gradually are decreased with the distance from the current lead. The method of calculating the conductivity of coke backfill based on percolation theory was used in this article, existing modeling concepts were developed and allowed to calculate the potential distribution depending on the physicochemical properties of the anodic zone.