The Commission shall make and publish a finding based upon the facts, testimony and evidence received at the public hearing together with any other relevant facts available from official publications of the United States or any state or any institution of recognized standing and the Commission is empowered to take "judicial notice" of such publications. Such findings shall be made upon every material point controverted at the hearing and required by this chapter and upon such matters and things as they may deem proper. The Commission shall issue a preliminary decision based upon the findings and such preliminary decision shall be delivered to all parties of record appearing at the hearing, or their representatives of record.