(1) All hearings shall be open to the public and conducted informally insofar as an orderly presentation will permit. Any interested party to the proceeding or a member of the commission may introduce any material evidence or examine or cross-examine any person present as a witness. The commission shall consider all evidence presented or introduced under oath at the hearing and all other pertinent documents, papers, or records available to it, and shall not be bound by any laws of evidence of this state.

(2) A full and complete record shall be kept of all proceedings and all testimony shall be recorded, but need not be transcribed unless the matter be further appealed.

(3) Four members of the commission shall constitute a quorum, one of whom must be the chairman. No member shall sit as a member of the commission to hear any matter in which he has a personal interest, nor shall he represent any interested party or witness at the hearing. Any interested party may challenge any member of the commission in writing, served upon the chairman of the commission, 5 days in advance of any scheduled appeal hearing, stating the reasons therefor, and if the commission shall find merit in the challenge, it shall disqualify the challenged member. The decision of any three commission members shall constitute the decision of the com-mision on any issue presented for its decision. The commission shall have continuing jurisdiction over all matters heard by it, to examine additional evidence or to hear additional testimony, and to revise, modify, alter, amend, or reverse all demands, findings, and decisions made by it at any time and shall not lose jurisdiction unless and until jurisdiction has been taken by a court of competent jurisdiction in a proceeding filed therein. The commission may postpone or continue a hearing from time to time as it deems necessary.

(4) As soon as possible after the hearing, the commission shall render its decision in writing, stating its findings and conclusions to be signed by all commission members joining in the decision. If the appellant or his representative fails to appear at the hearing after due notice, and good cause for continuance is not shown, the commission shall render its decision upon the evidence presented to it. Copies of such decision shall be mailed to the appellant or his representative and shall be kept on file in the office of the commission in Helena, Montana, open to public inspection. The decision of the commission shall become final upon mailing of the same to the appellant.