Why Coke Breeze Backfill?
With the right coke breeze backfill, anode-to-earth resistance is decreased, since the backfill column functions as the anode rather than just the anode material itself. Gas blockage and drying tendencies are decreased by the increased anodic reaction surface area. Anode life is increased by the shift of the oxidation reaction from the anode surface to the backfill surface. Also, the backfill maintains hole integrity and prevents cave-in.
Since the purpose of the carbonaceous backfill is to provide an electronic path for current flow, low resistivity, particle size, and specific gravity are important backfill properties. Low resistivity favors electronic current flow to the backfill / ground interface. Small particle size and high density favor electronic current flow between the anode material and backfill by improving contact between the anode material and the backfill.