Mo. Rev. Stat. § 477.082
From January 1, 1972, the commissioners of the supreme court, in addition to their other duties, by order of the supreme court, may be temporarily assigned for the performance of judicial duties as special judges of the supreme court, of any district of the court of appeals, or of any circuit court when their services are required for the prompt and efficient administration of justice. During such temporary assignments, subject to the supervision of the regular judge or judges of the court, the commissioners shall exercise the same powers, duties, and responsibilities as are vested by law in the regular judges of the court to which they are assigned.
(L. 1971 S.B. 117 § 2)
Effective 1-1-72