2016-11-23_REPORT - C1981019 (3)

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West Pit Fill Inspection Certification On November 10, 2016, 1 inspected the area in which the West Pit Excess Spoil Fill was constructed. The purpose of this inspection was to observe the surface rock drain that borders the 3H:1 V Excess Fill Slope, inspect the areas dumped to final grade, inspect the revegetation on the fill surface, inspect the fill for areas of water seepage or surface drainage, inspect the final grade slopes, and satisfy the requirements of CDRMS Rule 4.09.1(1)(c) and Rule 4.09.1(11). At the time of inspection, weather conditions were approximately 65°F and sunny. Based upon my observations, the regraded fill was observed to be stable and unchanged. The underdrain below the West Pit Fill was not seeping at the time of inspection. No other seeps, slumps or signs of significant erosion were noted on the fill surface. The current water level of the monitoring piezometer was obtained. The water level taken at the time of inspection was 83.0 feet from the ground surface, an decrease in water elevation of 0.2 feet from the previous quarterly inspection. I reviewed the monument survey data collected on November 15, 2016. This data was compared to the survey data collected during the previous quarter on September 20, 2016. After review of the November 15, 2016 data, the largest indicated vertical displacement from the third quarter 2016 survey was 0.116 feet at the 7150 West Prism. The displacement of the 7150 West Prism from the second quarter 2016 was 0.038, indicating a minor survey discrepancy of the 7150 West Prism during the third quarter 2016. The remaining prisms measured a displacement of -0.015 feet to 0.073 ft. Based on the prism data, the displacement of the monuments are not of concern with regard to the stability of the fill. The degree of measured displacement can be caused by normal settlement, survey variation, and monument disturbance from animal traffic, weather etc. During inspection, I observed no evidence of structural weakness, slumps, seeps or other hazardous conditions associated with this fill. The monument survey data is available for review upon request at the Colowyo Mine site. I am a Registered Professional Engineer in the State of Colorado. Being familiar with the Colowyo operation, and relying on the information provided to me by Colowyo Personnel, the West Pit Excess Spoil Fill is observed to be stable, at the time of inspection, and in compliance with CDRMS Rule 4.09.1(1)(c) and Rule 4.09.1(11) , and Permit C-1981-019. �P0 L CF,LV! • SAS 47031ess