A pair of Colorado Department of Transportation workers place solar-powered Talon 90 sensors near the top of the rocky cliff face high above I-70 as they work on rock mitigation in De Beque Canyon on Monday. CDOT is placing the sensors that measure acceleration by using gravity to watch for rocks shifting on the cliff face, according to engineer Chris Robinson of Silent Solutions, the Conifer, Colo., company that designed and built the Talon 90s. The information gathered by the sensors, which will cover about a mile of the cliff above the road, will be transmitted to a site on top. Eastbound traffic on the interstate was narrowed to a single lane, and some delays due to the work occurred. Work and delays may continue today (Tuesday) if the job is not completed on Monday.