(1) If historic or prehistoric properties or paleontological remains are identified during the course of the action the agency shall, in accordance with 22-3-435, MCA, notify the SHPO immediately, provide information on the property and stop any work that could harm the property. The SHPO shall assess the property's value as a heritage property or paleontological remains within two days. The time for evaluation may be extended upon request by SHPO and concurrence by the agency. The agency shall subsequently consider any adverse effects on heritage properties according to ARM 10.121.907(1) through (3) and report its mitigation plan to the SHPO immediately upon completion of that plan.