A method of operating a blast furnace enables substantial improvement of gas permeability and liquid permeability for stable operation of the blast furnace, involves packing the core section with solid high strength, carbonaceous blocks prior to ignition of the furnace. The carbon blocks resist wearing and high temperature reaction over very long periods of operating time, greatly stabilizing the furnace. Because of the improved stabilization, gas permeability and liquid permeability, a low grade solid reducing agent can be substituted for a quantity of the high quality coke normally used for operating the blast furnace and furthermore enables injection of pulverized coal at a rate of at least 200 Kg/ton-pig.