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FA <br />West Pit Fill Inspection Certification <br />On December 12th, 2017, 1 inspected the area in which the West Pit Excess Spoil Fill was <br />constructed. The purpose of this inspection was to observe the surface rock drain that borders the <br />3H:1V Excess Fill Slope, inspect the areas dumped to final grade, inspect the revegetation on the <br />fill surface, inspect the fill for areas of water seepage or surface drainage, inspect the final grade <br />slopes, and satisfy the requirements of CDRMS Rule 4.09.1(1)(c) and Rule 4.09.1(11). At the time <br />of inspection, weather conditions were approximately 35°F and sunny. <br />Based upon my observations, the regraded fill was observed to be stable and unchanged. The <br />underdrain below the West Pit Fill was not seeping at the time of inspection. No other seeps, <br />slumps or signs of significant erosion were noted on the fill surface. <br />The current water level of the monitoring piezometer was obtained. The water level taken at the <br />time of inspection was 78.9 feet from the ground surface, a decrease in water level of 0.8 feet from <br />the previous quarterly inspection. <br />I reviewed the monument survey data collected on December 13th, 2017. This data was compared <br />to the survey data collected during the previous quarter on August 23, 2017. After review of the <br />December 13th, 2017 data, the largest indicated vertical displacement from the first quarter 2017 <br />survey was -0.027' at the 7150 West prism. All other prisms measured less than -0.021 feet of <br />vertical displacement. <br />Based on the prism data, the displacement of the monuments are not a concern with regard to the <br />stability of the fill. The degree of measured displacement can be caused by normal settlement, <br />survey variation, and monument disturbance from animal traffic, weather etc. During inspection, I <br />observed no evidence of structural weakness, slumps, seeps or other hazardous conditions <br />associated with this fill. The monument survey data is available for review upon request at the <br />Colowyo Mine site. <br />I am a Registered Professional Engineer in the State of Colorado. Being familiar with the Colowyo <br />operation, and relying on the information provided to me by Colowyo Personnel, the West Pit <br />Excess Spoil Fill is observed to be stable, at the time of inspection, and in compliance with CDRMS <br />Rule 4.09.1(1)(c) and Rule 4.09.1(11), and Permit C-1981-019. <br />CR- O 's� •.,cF� �� <br />AW <br />031 S <br />�� ��f2-IS-17 <br />0 •. .• �� <br />11111111"I ON������ <br />