Where an undesignated or otherwise unknown underground facility is discovered within a work area, the excavator shall report such discovery as follows:
(a) If the identity of the operator of the discovered underground facility is known or is obvious, the excavator shall report the discovery to such operator. The operator shall respond immediately and, in accordance with subdivision 753-4.9(d) of this Part, take any necessary action and advise the excavator as to whether he or she may proceed in the immediate area.
(b)
(1) If the identity of the operator of the discovered underground facility is not known or obvious, the excavator shall report the discovery to the one-call notification system and each operator notified by the one-call notification system shall respond immediately and, in accordance with section 753-4.9(d) of this Part, determine whether or not such discovered facility is his or hers.
(2) While awaiting a determination of ownership, the excavator may proceed with the excavation or demolition taking reasonable care to protect and prevent damage to such underground facility.